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Sample records for myocardial flow tracer

  1. Kinetic analysis of 18F-fluorodihydrorotenone as a deposited myocardial flow tracer: Comparison to thallium-201.

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Robert C.; Powers-Risius, Patricia; Reutter, Bryan W.; O' Neil, James P.; La Belle, Michael; Huesman, Ronald H.; VanBrocklin, Henry F.

    2004-03-01

    The goal of this investigation was to assess the accuracy of 18F-fluorodihydrorotenone (18F-FDHR) as a new deposited myocardial flow tracer and compare the results to those for 201Tl. Methods. The kinetics of these flow tracers were evaluated in 22 isolated, erythrocyte- and albumin-perfused rabbit hearts over a flow range encountered in patients. The two flow tracers plus a vascular reference tracer (131I-albumin) were introduced as a bolus through a port just above the aortic cannula. Myocardial extraction, retention, washout, and uptake parameters were computed from the venous outflow curves using the multiple indicator dilution technique and spectral analysis. Results. The mean initial extraction fractions of 18F-FDHR (0.85 +- 0.07) and 201Tl (0.87 +- 0.05) were not significantly different, although the initial extraction fraction for 18F-FDHR declined with flow (P < 0.0001), whereas the initial extraction fraction of 201Tl did not. Washout of 201Tl was faster (P < 0.001) and more affected by flow (P < 0.05) than 18F-FDHR washout. Except for initial extraction fraction, 18F-FDHR retention was greater (P < 0.001) and less affected by flow (P < 0.05) than 201Tl retention. Reflecting its superior retention, net uptake of 18F-FDHR was better correlated with flow than 201Tl uptake at both one and fifteen minutes after tracer introduction (P < 0.0001 for both comparisons). Conclusion. The superior correlation of 18F-FDHR uptake with flow indicates that it is a better flow tracer than 201Tl in the isolated rabbit heart. Compared to the other currently available positron-emitting flow tracers (82Rb, 13N-ammonia, and 15O-water), 18F-FDHR has the potential of providing excellent image resolution without the need for an on-site cyclotron.

  2. SPECT Myocardial Blood Flow Quantitation Concludes Equivocal Myocardial Perfusion SPECT Studies to Increase Diagnostic Benefits.

    Science.gov (United States)

    Chen, Lung-Ching; Lin, Chih-Yuan; Chen, Ing-Jou; Ku, Chi-Tai; Chen, Yen-Kung; Hsu, Bailing

    2016-01-01

    Recently, myocardial blood flow quantitation with dynamic SPECT/CT has been reported to enhance the detection of coronary artery disease in human. This advance has created important clinical applications to coronary artery disease diagnosis and management for areas where myocardial perfusion PET tracers are not available. We present 2 clinical cases that undergone a combined test of 1-day rest/dipyridamole-stress dynamic SPECT and ECG-gated myocardial perfusion SPECT scans using an integrated imaging protocol and demonstrate that flow parameters are capable to conclude equivocal myocardial perfusion SPECT studies, therefore increasing diagnostic benefits to add value in making clinical decisions.

  3. Myocardial scintigraphy with /sup 201/Tl and quantitative assessment of myocardial blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Y; Kanbara, H; Yonekura, Y; Kadota, K; Fujita, T [Kyoto Univ. (Japan). Faculty of Medicine

    1976-12-01

    A newly introduced radionuclide for myocardial imaging, /sup 201/Tl, was studied. Twenty-two subjects consisting of 7 normals, 12 with ischemic heart disease and 3 with hypertrophic cardiomyopathy (HCM) were selected. On intravenous administration of /sup 201/Tl(1.5 to 20. mCi), initial transit of the tracer through the heart, as well as subsequent uptake by the myocardium, were recorded by a scintillation camera. The later process showed the distribution of the myocardial blood flow (MBF). A normal myocardial scintigraphy revealed the left-sided myocardial mass predominantly, whereas the right side or the septum predominated in the case of tetralogy of fallot (T/F) or idiopathic hypertrophic subuaortic stenosis (IHSS). An ischemic or infarcted area of the myocardium in ischemic heart disease (IHD) was compatible with electrocardiographic findings, and revealed defects even in an equivocal case on ECG. Since the ratio of radioactivity taken up by the myocardium (U) to the total injected dosis (I) is assumed to be proportional to the fractional MBF of cardiac output (CO), MBF/CO is calculated by ratio of the radioactivity selected from myocardial region on the later recording to that from the entire region on the initial transit of the tracer bolus. The average MBF/CO of normals was 4.4 +- 0.5%, IHD 4.0 +- 0.8% and HCM 5.5 +- 1.2%. On exercise loading, a significant increase of this value was observed in normals, whereas no change was observed in IHD.

  4. Regional myocardial blood flow, metabolism and function assessed noninvasively by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Schelbert, H.R.; Phelps, M.E.; Hoffman, E.; Huang, S.; Kuhl, D.E.

    1979-01-01

    Positron emission computed tomography is a new technique for the noninvasive measure of myocardial blood flow, mechanical function and, in particular, metabolism. The capability of this new study means is due to the technological innovations of the imaging device and the availability of radioactive tracers that are specific for blood flow and metabolism. The device permits recording of cross-sectional images of the left ventricular myocardium that reflect quantitatively regional tracer tissue concentrations. By employing tracer kinetic models this new technique permits the measurement of regional glucose and fatty acid metabolism of the heart. While already an important new tool for investigative studies into cardiac physiology and pathophysiology, the clinical utility of positron emission tomography remains to be defined.

  5. Regional myocardial blood flow, metabolism and function assessed noninvasively by positron emission tomography

    International Nuclear Information System (INIS)

    Schelbert, H.R.; Phelps, M.E.; Hoffman, E.; Huang, S.; Kuhl, D.E.

    1979-01-01

    Positron emission computed tomography is a new technique for the noninvasive measure of myocardial blood flow, mechanical function and, in particular, metabolism. The capability of this new study means is due to the technological innovations of the imaging device and the availability of radioactive tracers that are specific for blood flow and metabolism. The device permits recording of cross-sectional images of the left ventricular myocardium that reflect quantitatively regional tracer tissue concentrations. By employing tracer kinetic models this new technique permits the measurement of regional glucose and fatty acid metabolism of the heart. While already an important new tool for investigative studies into cardiac physiology and pathophysiology, the clinical utility of positron emission tomography remains to be defined

  6. Nuclear medicine and coronary artery disease: evaluation of tracers of myocardial perfusion and vulnerable atherosclerotic plaque

    International Nuclear Information System (INIS)

    Broisat, A.

    2005-04-01

    Coronary artery disease is one of the primary cause of mortality worldwide. Nuclear medicine is the major imaging technique for diagnosis and following of this disease. perfusion: nowadays, major radioactive agents used in clinical practice are myocardial perfusion tracers. The reference tracer is thallium-201. However, 201 Tl presents some drawbacks. 99m Tcn-noet has been proposed for its replacement. This study shows that in contrast with previous studies realized in vitro on cardio myocytes, verapamil, an l-type calcium channel inhibitor, does not inhibit myocardial fixation of 99m Tcn-noet in vivo in dog. This data is in agreement with the hypothesis of a non specific endothelial fixation of this tracer. Moreover, this study shows that as a pure tracer of myocardial perfusion, 99m Tcn-noet can also be used to assess myocardial viability on a model of myocardial chronic infarction in rat. atherosclerosis: disruption of vulnerable atherosclerotic plaques is the main event leading to coronary accidents. The second part of this study concerns the evaluation of new potential tracers of the vulnerable atherosclerotic plaque in an experimental model of rabbit with an inheritable hypercholesterolemia. The four tracers evaluated (b2702(r), b2702-I, b2702-Tc and Tc-raft-b2702) are synthetic peptides comprising the residues 75-84 of hla-b2702, a molecule known to link vcam-1, an adhesion molecule expressed in vulnerable atherosclerotic plaque. The autoradiography studies show that all tracers accumulate within atherosclerotic plaque expressing vcam- and that. i-b2702 shows the best plaque/control fixation ratio. (author)

  7. Quantitative assessment of myocardial blood flow by measurement of fractional myocardial uptake of 201Tl

    International Nuclear Information System (INIS)

    Yonekura, Yoshiharu; Ishii, Yasushi; Torizuka, Kanji; Kadota, Kazunori; Kambara, Hirofumi

    1980-01-01

    Fractional Myocardial uptake of 201 Tl was measured for the quantitative assessment of myocardial blood flow in coronary artery disease (CAD). 10 normals and 28 CAD, 7 of which have less than 50% stenosis (CAD I) and 21 of which have more than 50% stenosis (CAD II) in the proximal portion of coronary arteries, were studied at rest and with submaximal exercise loading by bicycle ergometer. After intravenous injection of 201 Tl, its rapid transport process was recorded during the initial 5 minutes by a scintillation camera and a minicomputer. Total injected dosage (T) was obtained from the counts of the entire chest region during the initial passage of the tracer through the heart and lung. Myocardial uptake (M) was counted with the same geometry from the subsequent accumulation within the myocardial region with subtraction of the background activities in the upper mediastinal region (B). The fractional myocardial uptake of 201 Tl ((M-B)/T) is assumed to be proportional to the fractional myocardial blood flow to cardiac output (MBF/CO) according to the indicator fractionation principle. The average value of MBF/CO at rest in CAD (4.11 +- 1.12%) was significantly greater than in normals (3.36 +- 0.49%), which may be caused by an increased left ventricular mass in CAD. Change rate of MBF/CO on the exercise loading was significantly less in CAD I (1.36 +- 0.14) and in CAD II (1.11 +- 0.21) than in normals (1.75 +- 0.11). MBF/CO increased proportionally to the increment of the double product of heart rate and systolic blood pressure by exercise loading in normals, whereas it didn't in CAD. The sensitivity of this method was superior to the stress electrocardiogram and the stress myocardial perfusion imaging, not only in CAD II but also in CAD I. This result indicated that this type of global assessment of the myocardial reserve capacity is valuable in addition to the simple stress myocardial perfusion imaging. (author)

  8. Myocardial uptake characteristics of three 99mTc-labeled tracers for myocardial perfusion imaging one hour after rest injection

    International Nuclear Information System (INIS)

    Manka-Waluch, A.; Palmedo, H.; Reinhardt, M.J.; Joe, A.Y.; Manka, C.; Guhlke, S.; Biersack, H.J.; Bucerius, J.

    2006-01-01

    99m Tc-tetrofosmin and 99m Tc-sestamibi are approved tracers for myocardial perfusion studies. Recently, a 99m Tc-methoxyisobutylisonitrile (MIBI) preparation from a different manufacturer ( 99m Tc-cardiospect-MIBI) has been introduced to the market. Therefore, the aim of this study was the evaluation of 99m Tc-tetrofosmin as well as of two different 99m Tc-labeled MIBI tracers with regard to differences in imaging quality under resting conditions. Sixty patients (mean age 63.8 years±1.25) with known or suspected coronary artery disease but without evidence of rest-ischemia were included. Twenty patients in each group were examined by a two-day-rest-stress protocol using the three 99m Tc-labeled tracers. Visual analysis of all images was performed by two experienced physicians blinded with regard to the applied tracer. Regions of interest (ROI) were defined over the heart, lung and whole body only in the rest imaging in order to calculate heart-to-lung, lung-to-whole body-, and heart-to-whole body-ratios. The heart-to-lung ratio was statistically significant higher for 99 m T c-cardiospect-MIBI as compared to 99m Tc-sestamibi as well as to 99m Tc-tetrofosmin. Furthermore, a significantly higher heart-to-lung ratio was found for 99m Tc-sestamibi as compared to 99m Tc-tetrofosmin. The heart-to-whole body-ratio and the lung-to-whole body-ratio were equivalent between all tracers. Visual analysis revealed only slight differences regarding image quality between all tracers. ROI analysis surprisingly revealed a significant higher myocardial uptake and consequently a higher heart-to-lung ratio for 99m Tc-cardiospect-MIBI. Whether this leads to a better visual image quality has to be evaluated in future studies with larger study populations as well as semiquantitative segmental analysis of the myocardial perfusion images. (author)

  9. Spectral analysis for evaluation of myocardial tracers for medical imaging

    International Nuclear Information System (INIS)

    Huesman, Ronald H.; Reutter, Bryan W.; Marshall, Robert C.

    2000-01-01

    Kinetic analysis of dynamic tracer data is performed with the goal of evaluating myocardial radiotracers for cardiac nuclear medicine imaging. Data from experiments utilizing the isolated rabbit heart model are acquired by sampling the venous blood after introduction of a tracer of interest and a reference tracer. We have taken the approach that the kinetics are properly characterized by an impulse response function which describes the difference between the reference molecule (which does not leave the vasculature) and the molecule of interest which is transported across the capillary boundary and is made available to the cell. Using this formalism we can model the appearance of the tracer of interest in the venous output of the heart as a convolution of the appearance of the reference tracer with the impulse response. In this work we parameterize the impulse response function as the sum of a large number of exponential functions whose predetermined decay constants form a spectrum, and each is required only to have a nonnegative coefficient. This approach, called spectral analysis, has the advantage that it allows conventional compartmental analysis without prior knowledge of the number of compartments which the physiology may require or which the data will support

  10. Quantitative myocardial blood flow with Rubidium-82 PET

    DEFF Research Database (Denmark)

    Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identificat......Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1...... global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability...

  11. Tracer dispersion in planar multipole flows

    International Nuclear Information System (INIS)

    Koplik, J.; Redner, S.; Hinch, E.J.

    1994-01-01

    We study the motion of passive Brownian tracer particles in steady two-dimensional potential flows between sources and sinks. Our primary focus is understanding the long-time properties of the transit time probability distribution for the tracer to reach the sink p(t) and the influence of the flow geometry on this probability. A variety of illustrative case studies is considered. For radial potential flow in an annular region, competition between convection and diffusion leads to nonuniversal decay of the transit time probability. Dipolar and higher multipole flows are found to exhibit generic features, such as a power-law decay in p(t) with an exponent determined by the multipole moment, an exponential cutoff related to stagnation points, and a ''shoulder'' in p(t) that is related to reflection from the system boundaries. For spatially extended sinks, it is also shown that the spatial distribution of the collected tracer is independent of the overall magnitude of the flow field and that p(t) decays as a power law with a geometry-dependent exponent. Our results may offer the possibility of using tracer measurements to characterize the flow geometry of porous media

  12. SPECT myocardial blood flow quantitation toward clinical use: a comparative study with {sup 13}N-Ammonia PET myocardial blood flow quantitation

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Bailing [University of Missouri-Columbia, Nuclear Science and Engineering Institute, Columbia, Missouri (United States); Hu, Lien-Hsin; Yang, Bang-Hung; Ting, Chien-Hsin; Huang, Wen-Sheng [Taipei Veterans General Hospital, Department of Nuclear Medicine, Taipei (China); Chen, Lung-Ching [Shin Kong Wu-Ho Su Memorial Hospital, Division of Cardiology, Taipei (China); Chen, Yen-Kung [Shin Kong Wu-Ho Su Memorial Hospital, Department of Nuclear Medicine, Taipei (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); Wu, Tao-Cheng [National Yang-Ming University, Cardiovascular Research Center, Taipei (China)

    2017-01-15

    The aim of this study was to evaluate the accuracy of myocardial blood flow (MBF) quantitation of {sup 99m}Tc-Sestamibi (MIBI) single photon emission computed tomography (SPECT) compared with {sup 13}N-Ammonia (NH3) position emission tomography (PET) on the same cohorts. Recent advances of SPECT technologies have been applied to develop MBF quantitation as a promising tool to diagnose coronary artery disease (CAD) for areas where PET MBF quantitation is not available. However, whether the SPECT approach can achieve the same level of accuracy as the PET approach for clinical use still needs further investigations. Twelve healthy volunteers (HVT) and 16 clinical patients with CAD received both MIBI SPECT and NH3 PET flow scans. Dynamic SPECT images acquired with high temporary resolution were fully corrected for physical factors and processed to quantify K1 using the standard compartmental modeling. Human MIBI tracer extraction fraction (EF) was determined by comparing MIBI K1 and NH3 flow on the HVT group and then used to convert flow values from K1 for all subjects. MIBI and NH3 flow values were systematically compared to validate the SPECT approach. The human MIBI EF was determined as [1.0-0.816*exp(-0.267/MBF)]. Global and regional MBF and myocardial flow reserve (MFR) of MIBI SPECT and NH3 PET were highly correlated for all subjects (global R{sup 2}: MBF = 0.92, MFR = 0.78; regional R{sup 2}: MBF ≥ 0.88, MFR ≥ 0.71). No significant differences for rest flow, stress flow, and MFR between these two approaches were observed (All p ≥ 0.088). Bland-Altman plots overall revealed small bias between MIBI SPECT and NH3 PET (global: ΔMBF = -0.03Lml/min/g, ΔMFR = 0.07; regional: ΔMBF = -0.07 - 0.06, ΔMFR = -0.02 - 0.22). Quantitation with SPECT technologies can be accurate to measure myocardial blood flow as PET quantitation while comprehensive imaging factors of SPECT to derive the variability between these two approaches were fully addressed and corrected

  13. SPECT myocardial blood flow quantitation toward clinical use: a comparative study with "1"3N-Ammonia PET myocardial blood flow quantitation

    International Nuclear Information System (INIS)

    Hsu, Bailing; Hu, Lien-Hsin; Yang, Bang-Hung; Ting, Chien-Hsin; Huang, Wen-Sheng; Chen, Lung-Ching; Chen, Yen-Kung; Hung, Guang-Uei; Wu, Tao-Cheng

    2017-01-01

    The aim of this study was to evaluate the accuracy of myocardial blood flow (MBF) quantitation of "9"9"mTc-Sestamibi (MIBI) single photon emission computed tomography (SPECT) compared with "1"3N-Ammonia (NH3) position emission tomography (PET) on the same cohorts. Recent advances of SPECT technologies have been applied to develop MBF quantitation as a promising tool to diagnose coronary artery disease (CAD) for areas where PET MBF quantitation is not available. However, whether the SPECT approach can achieve the same level of accuracy as the PET approach for clinical use still needs further investigations. Twelve healthy volunteers (HVT) and 16 clinical patients with CAD received both MIBI SPECT and NH3 PET flow scans. Dynamic SPECT images acquired with high temporary resolution were fully corrected for physical factors and processed to quantify K1 using the standard compartmental modeling. Human MIBI tracer extraction fraction (EF) was determined by comparing MIBI K1 and NH3 flow on the HVT group and then used to convert flow values from K1 for all subjects. MIBI and NH3 flow values were systematically compared to validate the SPECT approach. The human MIBI EF was determined as [1.0-0.816*exp(-0.267/MBF)]. Global and regional MBF and myocardial flow reserve (MFR) of MIBI SPECT and NH3 PET were highly correlated for all subjects (global R"2: MBF = 0.92, MFR = 0.78; regional R"2: MBF ≥ 0.88, MFR ≥ 0.71). No significant differences for rest flow, stress flow, and MFR between these two approaches were observed (All p ≥ 0.088). Bland-Altman plots overall revealed small bias between MIBI SPECT and NH3 PET (global: ΔMBF = -0.03Lml/min/g, ΔMFR = 0.07; regional: ΔMBF = -0.07 - 0.06, ΔMFR = -0.02 - 0.22). Quantitation with SPECT technologies can be accurate to measure myocardial blood flow as PET quantitation while comprehensive imaging factors of SPECT to derive the variability between these two approaches were fully addressed and corrected. (orig.)

  14. Effect of decreased blood flow and ischemia on myocardial thallium clearance

    International Nuclear Information System (INIS)

    Okada, R.D.; Pohost, G.M.

    1984-01-01

    To determine the effect of reduced coronary blood flow on myocardial thallium-201 clearance over a range of flows, miniature radiation detectors were inserted into the left ventricular apex and positioned against the anterior and posterior endocardial walls in 21 dogs. Thallium was administered intravenously and myocardial tracer activity was monitored continuously for 1 hour in both walls. A balloon occluder was then partially inflated around the left anterior descending coronary artery in 19 dogs, producing a range of anterior wall blood flow reductions as assessed by the microsphere technique. Thallium activity was monitored continuously for 3 hours in both walls. Two dogs served as control animals and had no coronary artery occlusion at 1 hour. At the end of the 4 hour experiment, the dogs were sacrificed and the hearts counted in a well counter. The 19 dogs with coronary artery stenosis were divided into three groups (mild, moderate and severe flow reduction groups) on the basis of their poststenosis anterior/posterior wall regional myocardial blood flow ratios. The two control dogs had similar thallium clearances in the anterior and posterior left ventricular walls during the 3 hour period, as assessed by the radiation detectors, and by a final anterior/posterior wall thallium ratio near unity. All three groups of dogs with coronary stenosis had comparable fractional thallium clearances from the anterior and posterior walls before and after the balloon occluder inflation. The final anterior/posterior left ventricular wall thallium ratios were not significantly different than unity for all three groups of dogs

  15. Characterization of 3D PET systems for accurate quantification of myocardial blood flow

    OpenAIRE

    Renaud, Jennifer M.; Yip, Kathy; Guimond, Jean; Trottier, Mikaël; Pibarot, Philippe; Turcotte, Éric; Maguire, Conor; Lalonde, Lucille; Gulenchyn, Karen; Farncombe, Troy; Wisenberg, Gerald; Moody, Jonathan; Lee, Benjamin; Port, Steven C.; Turkington, Timothy G

    2016-01-01

    Three-dimensional (3D) mode imaging is the current standard for positron emission tomography-computed tomography (PET-CT) systems. Dynamic imaging for quantification of myocardial blood flow (MBF) with short-lived tracers, such as Rb-82- chloride (Rb-82), requires accuracy to be maintained over a wide range of isotope activities and scanner count-rates. We propose new performance standard measurements to characterize the dynamic range of PET systems for accurate quantitative...

  16. Minimizing Patient-Specific Tracer Dose in Myocardial Perfusion Imaging Using CZT SPECT

    NARCIS (Netherlands)

    van Dijk, Joris David; Jager, Pieter L.; Ottervanger, Jan Paul; Slump, Cornelis H.; de Boer, Jaep; Oostdijk, Adrianus H.J.; van Dalen, Jorn A.

    Myocardial perfusion imaging (MPI) with SPECT is widely adopted in clinical practice but is associated with a relatively high radiation dose. The aim of this study was to determine the minimum product of tracer dose and scan time that will maintain diagnostic value for cadmium zinc telluride (CZT)

  17. Geologic flow characterization using tracer techniques

    International Nuclear Information System (INIS)

    Klett, R.D.; Tyner, C.E.; Hertel, E.S. Jr.

    1981-04-01

    A new tracer flow-test system has been developed for in situ characterization of geologic formations. This report describes two sets of test equipment: one portable and one for testing in deep formations. Equations are derived for in situ detector calibration, raw data reduction, and flow logging. Data analysis techniques are presented for computing porosity and permeability in unconfined isotropic media, and porosity, permeability and fracture characteristics in media with confined or unconfined two-dimensional flow. The effects of tracer pulse spreading due to divergence, dispersion, and porous formations are also included

  18. Our experience of blood flow measurements using radioactive tracers

    International Nuclear Information System (INIS)

    Danet, Bernard.

    1974-01-01

    A critical study of blood flow measuring methods is proposed. After a review of the various diffusible and non-diffusible radioactive tracers and the corresponding detector systems, the principles which allow to measure blood flow from the data so obtained, are studied. There is a different principle of flow measurement for each type of tracer. The theory of flow measurement using non-diffusible tracers (human serum albumin labelled with 131 I or sup(99m)Tc, 113 In-labelled siderophiline) and its application to cardiac flow measurement are described first. Then the theory of flow measurement using diffusible tracers ( 133 Xe, 85 Kr) and its application to measurement of blood flow through tissues (muscles and kidney particularly) are described. A personal experience of this various flow measurements is reported. The results obtained, the difficulties encountered and the improvments proposed are developed [fr

  19. Tracer technology modeling the flow of fluids

    CERN Document Server

    Levenspiel, Octave

    2012-01-01

    A vessel’s behavior as a heat exchanger, absorber, reactor, or other process unit is dependent upon how fluid flows through the vessel.  In early engineering, the designer would assume either plug flow or mixed flow of the fluid through the vessel.  However, these assumptions were oftentimes inaccurate, sometimes being off by a volume factor of 100 or more.  The result of this unreliable figure produced ineffective products in multiple reaction systems.   Written by a pioneering researcher in the field of chemical engineering, the tracer method was introduced to provide more accurate flow data.  First, the tracer method measured the actual flow of fluid through a vessel.  Second, it developed a suitable model to represent the flow in question.  Such models are used to follow the flow of fluid in chemical reactors and other process units, like in rivers and streams, or solid and porous structures.  In medicine, the tracer method is used to study the flow of chemicals—harmful  and harmless—in the...

  20. Reduced dose measurement of absolute myocardial blood flow using dynamic SPECT imaging in a porcine model

    International Nuclear Information System (INIS)

    Timmins, Rachel; Klein, Ran; Petryk, Julia; Marvin, Brian; Kemp, Robert A. de; Ruddy, Terrence D.; Wells, R. Glenn; Wei, Lihui

    2015-01-01

    Purpose: Absolute myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements provide important additional information over traditional relative perfusion imaging. Recent advances in camera technology have made this possible with single-photon emission tomography (SPECT). Low dose protocols are desirable to reduce the patient radiation risk; however, increased noise may reduce the accuracy of MBF measurements. The authors studied the effect of reducing dose on the accuracy of dynamic SPECT MBF measurements. Methods: Nineteen 30–40 kg pigs were injected with 370 + 1110 MBq of Tc-99m sestamibi or tetrofosmin or 37 + 111 MBq of Tl-201 at rest + stress. Microspheres were injected simultaneously to measure MBF. The pigs were imaged in list-mode for 11 min starting at the time of injection using a Discovery NM 530c camera (GE Healthcare). Each list file was modified so that 3/4, 1/2, 1/4, 1/8, 1/16, and 1/32 of the original counts were included in the projections. Modified projections were reconstructed with CT-based attenuation correction and an energy window-based scatter correction and analyzed with FlowQuant kinetic modeling software using a 1-compartment model. A modified Renkin-Crone extraction function was used to convert the tracer uptake rate K1 to MBF values. The SPECT results were compared to those from microspheres. Results: Correlation between SPECT and microsphere MBF values for the full injected activity was r ≥ 0.75 for all 3 tracers and did not significantly degrade over all count levels. The mean MBF and MFR and the standard errors in the estimates were not significantly worse than the full-count data at 1/4-counts (Tc99m-tracers) and 1/2-counts (Tl-201). Conclusions: Dynamic SPECT measurement of MBF and MFR in pigs can be performed with 1/4 (Tc99m-tracers) or 1/2 (Tl-201) of the standard injected activity without significantly reducing accuracy and precision

  1. Reduced dose measurement of absolute myocardial blood flow using dynamic SPECT imaging in a porcine model

    Energy Technology Data Exchange (ETDEWEB)

    Timmins, Rachel; Klein, Ran; Petryk, Julia; Marvin, Brian; Kemp, Robert A. de; Ruddy, Terrence D.; Wells, R. Glenn, E-mail: gwells@ottawaheart.ca [Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7 (Canada); Wei, Lihui [Nordion, Inc., Ottawa, Ontario K2K 1X8 (Canada)

    2015-09-15

    Purpose: Absolute myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements provide important additional information over traditional relative perfusion imaging. Recent advances in camera technology have made this possible with single-photon emission tomography (SPECT). Low dose protocols are desirable to reduce the patient radiation risk; however, increased noise may reduce the accuracy of MBF measurements. The authors studied the effect of reducing dose on the accuracy of dynamic SPECT MBF measurements. Methods: Nineteen 30–40 kg pigs were injected with 370 + 1110 MBq of Tc-99m sestamibi or tetrofosmin or 37 + 111 MBq of Tl-201 at rest + stress. Microspheres were injected simultaneously to measure MBF. The pigs were imaged in list-mode for 11 min starting at the time of injection using a Discovery NM 530c camera (GE Healthcare). Each list file was modified so that 3/4, 1/2, 1/4, 1/8, 1/16, and 1/32 of the original counts were included in the projections. Modified projections were reconstructed with CT-based attenuation correction and an energy window-based scatter correction and analyzed with FlowQuant kinetic modeling software using a 1-compartment model. A modified Renkin-Crone extraction function was used to convert the tracer uptake rate K1 to MBF values. The SPECT results were compared to those from microspheres. Results: Correlation between SPECT and microsphere MBF values for the full injected activity was r ≥ 0.75 for all 3 tracers and did not significantly degrade over all count levels. The mean MBF and MFR and the standard errors in the estimates were not significantly worse than the full-count data at 1/4-counts (Tc99m-tracers) and 1/2-counts (Tl-201). Conclusions: Dynamic SPECT measurement of MBF and MFR in pigs can be performed with 1/4 (Tc99m-tracers) or 1/2 (Tl-201) of the standard injected activity without significantly reducing accuracy and precision.

  2. Assessment of myocardial viability using 123I-labeled iodophenylpentadecanoic acid at sustained low flow or after acute infarction and reperfusion.

    Science.gov (United States)

    Yang, J Y; Ruiz, M; Calnon, D A; Watson, D D; Beller, G A; Glover, D K

    1999-05-01

    123I-labeled iodophenylpentadecanoic acid (IPPA) is a synthetic fatty acid that may be useful for determination of myocardial viability. We investigated the uptake and clearance kinetics of this tracer in canine models of ischemia and infarction. In protocol 1, 185 MBq (5 mCi) 123I-IPPA were injected intravenously in 19 dogs with 50% left anterior descending artery (LAD) flow reduction. In 9 dogs, 201TI was coinjected. In protocol 2, 5 dogs underwent LAD occlusion for 3 h, and 123I-IPPA was injected 60 min after reperfusion. All dogs had flow measured by microspheres, regional systolic thickening by ultrasonic crystals and measurements of postmortem risk area and infarct size. Tracer activities were quantified by gamma well counting and by serial imaging. In protocol 1 dogs with sustained low flow (50% +/- 4%) and absence of systolic thickening (-3.2% +/- 1%), 123I-IPPA defect magnitude (LAD/left circumflex artery [LCX] count ratios) decreased from 0.65 +/- 0.02 to 0.74 +/- 0.02 at 30 min and to 0.84 +/- 0.03 at 2 h (P < 0.01), indicative of rest redistribution. Final transmural 123I-IPPA LAD/LCX activity ratio (0.99 +/- 0.05) was significantly greater than the flow ratio (0.53 +/- 0.04) at injection, confirming complete rest redistribution. The final 123I-IPPA activity ratio was significantly greater than the 201TI ratio over the 2-h period (P < 0.01). In protocol 2 dogs that underwent 3 h of total LAD occlusion and reflow (infarct size = 51% +/- 13% of risk area), viability was overestimated with 123I-IPPA, because uptake averaged 64% of normal in the central necrotic region, where flow averaged < 10% of normal. These findings suggest that serial 123I-IPPA imaging may be useful for assessing myocardial viability under conditions of sustained low flow and myocardial asynergy, such as appears to exist in patients with chronic coronary artery disease and depressed left ventricular function. In contrast, 123I-IPPA given early after reperfusion following prolonged

  3. Regional Myocardial Blood Volume and Flow: First-Pass MR Imaging with Polylysine-Gd-DTPA

    Science.gov (United States)

    Wilke, Norbert; Kroll, Keith; Merkle, Hellmut; Wang, Ying; Ishibashi, Yukata; Xu, Ya; Zhang, Jiani; Jerosch-Herold, Michael; Mühler, Andreas; Stillman, Arthur E.; Bassingthwaighte, James B.; Bache, Robert; Ugurbil, Kamil

    2010-01-01

    The authors investigated the utility of an intravascular magnetic resonance (MR) contrast agent, poly-L-lysine-gadolinium diethylenetriaminepentaacetic acid (DTPA), for differentiating acutely ischemic from normally perfused myocardium with first-pass MR imaging. Hypoperfused regions, identified with microspheres, on the first-pass images displayed significantly decreased signal intensities compared with normally perfused myocardium (P < .0007). Estimates of regional myocardial blood content, obtained by measuring the ratio of areas under the signal intensity-versus-time curves in tissue regions and the left ventricular chamber, averaged 0.12 mL/g ± 0.04 (n = 35), compared with a value of 0.11 mL/g ± 0.05 measured with radiolabeled albumin in the same tissue regions. To obtain MR estimates of regional myocardial blood flow, in situ calibration curves were used to transform first-pass intensity-time curves into content-time curves for analysis with a multiple-pathway, axially distributed model. Flow estimates, obtained by automated parameter optimization, averaged 1.2 mL/min/g ± 0.5 [n = 29), compared with 1.3 mL/min/g ± 0.3 obtained with tracer microspheres in the same tissue specimens at the same time. The results represent a combination of T1-weighted first-pass imaging, intravascular relaxation agents, and a spatially distributed perfusion model to obtain absolute regional myocardial blood flow and volume. PMID:7766986

  4. Role of myocardial perfusion imaging in evaluating thrombolytic therapy for acute myocardial infarction

    International Nuclear Information System (INIS)

    Beller, G.A.

    1987-01-01

    Myocardial thallium-201 scintigraphy is being increasingly employed as a method for assessing the efficacy of coronary reperfusion in acute myocardial infarction. New thallium uptake after intracoronary tracer administration after successful recanalization indicates that nutrient blood flow has been successfully restored. One may also presume that some myocardial salvage occurred if thallium administered in this manner is transported intracellularly by myocytes with intact sarcolemmal membranes. However, if one injects thallium by way of the intracoronary route immediately after reperfusion, the initial uptake of thallium in reperfused myocardium may predominantly represent hyperemic flow and regional thallium counts measured may not be proportional to the mass of viable myocytes. When thallium is injected intravenously during the occlusion phase the degree of redistribution after thrombolysis is proportional to the degree of flow restoration and myocardial viability. When thallium is injected for the first time intravenously immediately after reperfusion, an overestimation of myocardial salvage may occur because of excess thallium uptake in the infarct zone consequent to significant hyperemia. Another approach to myocardial thallium scintigraphy in patients undergoing thrombolytic therapy is to administer two separate intravenous injections before and 24 hours or later after treatment. Finally, patients with acute myocardial infarction who receive intravenous thrombolytic therapy are candidates for predischarge exercise thallium-201 scintigraphy for risk stratification and detection of residual ischemia

  5. Natural stream flow-rates measurements by tracer techniques

    International Nuclear Information System (INIS)

    Cuellar Mansilla, J.

    1982-01-01

    This paper presents the study of the precision obtained measuring the natural stream flow rates by tracer techniques, especially when the system presents a great slope and a bed constituted by large and extended particle size. The experiences were realized in laboratory pilot channels with flow-rates between 15 and 130 [1/s]; and in natural streams with flow-rates from 1 to 25 m 3 /s. Tracer used were In-133m and Br-82 for laboratory and field measurements respectively. In both cases the tracer was injected as a pulse and its dilution measured collecting samples in the measured section, at constant flow-rates, of 5[1] in laboratory experiences and 60[1] of water in field experiences. Precisions obtained at a 95% confidence level were about 2% for laboratory and 3% for field. (I.V.)

  6. Rationale and radiopharmaceuticals for myocardial imaging

    International Nuclear Information System (INIS)

    Poe, N.D.

    1976-01-01

    Static radionuclide imaging procedures are now available for evaluating regional myocardial perfusion and for detecting acute myocardial infarction. Thallium-201, a radiopharmaceutical which possesses many of the characteristics of potassium analogs, at present is receiving the greatest attention as a regional blood flow indicator. Ischemic lesions appear as areas of decreased tracer uptake. Unfortunately, this agent is expensive, is in limited supply and has a photopeak which is low for optimum imaging. Positive infarct images can be obtained with various technetium-99m chelates. Pyrophosphate appears to be the best of the technetium compounds studied to date although the mechanism of uptake of the chelates has not yet been fully elucidated. Therefore, quantitative measurements of infarct size are not justified. As perfusion imaging and infarct imaging provide useful, complementary data, a dual tracer approach to evaluating patients with suspected coronary artery disease and/or myocardial infarction is probably justifiable

  7. Assessing preferential flow by simultaneously injecting nanoparticle and chemical tracers

    KAUST Repository

    Subramanian, S. K.; Li, Yan; Cathles, L. M.

    2013-01-01

    The exact manner in which preferential (e.g., much faster than average) flow occurs in the subsurface through small fractures or permeable connected pathways of other kinds is important to many processes but is difficult to determine, because most chemical tracers diffuse quickly enough from small flow channels that they appear to move more uniformly through the rock than they actually do. We show how preferential flow can be assessed by injecting 2 to 5 nm carbon particles (C-Dots) and an inert KBr chemical tracer at different flow rates into a permeable core channel that is surrounded by a less permeable matrix in laboratory apparatus of three different designs. When the KBr tracer has a long enough transit through the system to diffuse into the matrix, but the C-Dot tracer does not, the C-Dot tracer arrives first and the KBr tracer later, and the separation measures the degree of preferential flow. Tracer sequestration in the matrix can be estimated with a Peclet number, and this is useful for experiment design. A model is used to determine the best fitting core and matrix dispersion parameters and refine estimates of the core and matrix porosities. Almost the same parameter values explain all experiments. The methods demonstrated in the laboratory can be applied to field tests. If nanoparticles can be designed that do not stick while flowing through the subsurface, the methods presented here could be used to determine the degree of fracture control in natural environments, and this capability would have very wide ranging value and applicability.

  8. Tracer techniques for determination of groundwater flow parameters

    International Nuclear Information System (INIS)

    Drost, W.; Klotz, D.

    1988-05-01

    The most common one-borehole and multiple borehole methods using tracers for the direct determination of the groundwater flow parameters (velocity of flow, flow direction) and for the indirect determination of characteristic quantities of the aquifer (effective porosity, dispersivity, transmissivity) are presented methodically and their value is documented by practical examples. Especially, the properties of and measuring technique with suitable tracers are considered (e.g. T, Na-24, Cr-51, Co-58, Co-60, Br-82, Tc-99, I-125, I-131, Au-198). (orig./HP) [de

  9. Quantitation of myocardial blood flow and myocardial flow reserve with 99mTc-sestamibi dynamic SPECT/CT to enhance detection of coronary artery disease

    International Nuclear Information System (INIS)

    Hsu, Bailing; Chen, Fu-Chung; Chen, Chien-Cheng; Wu, Tao-Cheng; Huang, Wen-Sheng; Hou, Po-Nien; Hung, Guang-Uei

    2014-01-01

    Conventional dual-head single photon emission computed tomography (SPECT)/CT systems capable of fast dynamic SPECT (DySPECT) imaging have a potential for flow quantitation. This study introduced a new method to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) with DySPECT scan and evaluated the diagnostic performance of detecting coronary artery disease (CAD) compared with perfusion using invasive coronary angiography (CAG) as the reference standard. This study included 21 patients with suspected or known CAD who had received DySPECT, ECG-gated SPECT (GSPECT), and CAG (13 with ≥50 % stenosis in any vessel; non-CAD group: 8 with patent arteries or 99m Tc-sestamibi (MIBI) tracer at rest or dipyridamole-stress stages. DySPECT images were reconstructed with full physical corrections and converted to the physical unit of becquerels per milliliter. Stress MBF (SMBF), rest MBF (RMBF), and MFR were quantified by a one-tissue compartment flow model using time-activity curves derived from DySPECT images. Perfusion images were processed for GSPECT scan and interpreted to obtain summed stress score (SSS) and summed difference score (SDS). Receiver-operating characteristic (ROC) analyses were conducted to evaluate the diagnostic performance of flow and perfusion. Using the criteria of ≥50 % stenosis as positive CAD, areas under the ROC curve (AUCs) of flow assessment were overall significantly greater than those of perfusion. For patient-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.91 ± 0.07, 0.86 ± 0.09, 0.64 ± 0.12, and 0.59 ± 0.13. For vessel-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.81 ± 0.05, 0.76 ± 0.06, 0.62 ± 0.07, and 0.56 ± 0.08, respectively. The preliminary data suggest that MBF quantitation with a conventional SPECT/CT system and the flow quantitation method is a clinically effective approach to enhance CAD detection. (orig.)

  10. Tritium as tracer of flow in constructed wetlands

    International Nuclear Information System (INIS)

    Wachniew, P.; Czuprynski, P.; Maloszewski, P.

    2005-01-01

    Constructed wetlands technology is a cost-effective and environmentally friendly method used world-wide to treat waste waters of different origins. The soluble pollutants are transformed and removed mainly through the processes that occur at surfaces of plants, plant debris or filtering media. The efficiency of soluble pollutants removal is thus primarily related to the extent of contact between waste waters and the reactive surfaces. Residence time distributions function (RTD)is basic characteristic of wetland hydraulic properties and can be obtained by combined use of tracer technique and mathematical modelling. Tritium was used as to obtain RTD's of three parallel cells of a sub-surface flow constructed wetland overgrown with Pharagmites australis in Nowa Slupia. Tritium as a part of water molecule, is an ideal tracer of flow in the highly reactive environment of constructed wetlands. Results of the tracer test interpreted by the assumed model (Multi Flow Dispersion Model) of conservative solute transport revealed a complex structure of flow through the wetland. (author)

  11. Radioisotope tracers in industrial flow studies

    International Nuclear Information System (INIS)

    Easey, J.F.

    1987-01-01

    The scope of radioisotope tracer work carried out by ANSTO has involved most sectors of Australian industry including iron and steel coal, chemical, petrochemical, natural gas, metallurgical, mineral, power generation, liquified air plant, as well as port authorities, water and sewerage instrumentalities, and environmental agencies. A major class of such studies concerns itself with flow and wear studies involving industrial equipment. Some examples are discussed which illustrate the utility of radioisotope tracer techniques in these applications

  12. A comparison of resting images from two myocardial perfusion tracers

    International Nuclear Information System (INIS)

    Anagnostopoulos, C.; Laney, R.; Pennell, D.; Proukakis, H.; Underwood, R.

    1995-01-01

    We have compared stress-redistribution and delayed rest thallium-201 with rest technetium-99m methoxyisobutylisonitrile (MIBI) tomograms in order to compare the tracers for the assessment of myocardial viability and to validate a rapid protocol combining the two tracers. We studied 30 consecutive patients with known or suspected coronary artery disease [group 1: 16 with normal left ventricular function, mean left ventricular ejection fraction (LVEF) 55%, SD 6%; group 2: 14 with abnormal function, mean LVEF 28%, SD 8%]. 201 Tl was injected during infusion of adenosine followed by acquisition of conventional stress and redistribution tomograms. On a separate day, 201 Tl was injected at rest with imaging 4 h later. 99m Tc-MIBI was then given at rest and imaging was performed. Three images were compared: redistribution 201 Tl, rest 201 Tl, and rest 99m Tc-MIBI. Tracer activity was classified visually and quantitatively in nine segments and segments with>50% activity were defined as containing clinically significant viable myocardium. Mean global tracer uptake as a percentage of maximum was similar in group 1 (rest 201 Tl 69%±12%, redistribution 201 Tl 69%±15%, rest 99m Tc-MIBI 70%±13%), but in group 2 mean tracer uptake was significantly greater in the rest 201 Tl images (59%±16%) than in redistribution 201 Tl images (53%±17%) or rest 99m Tc-MIBI images (53%±19%). Overall agreement for regional uptake score was excellent (κ from 0.79 to 0.84), although there were a significant number of segments with less uptake shown by redistribution 201 Tl and by rest 99m Tc-MIBI than by rest 201 Tl in group 2. The number of segments with significant viable myocardium in group 1 was very similar between the three images but in group 2 rest 201 Tl identified significantly more segments as viable than the other images. (orig./MG) (orig.). With 1 fig., 7 tabs

  13. VO(2peak), myocardial hypertrophy, and myocardial blood flow in endurance-trained men.

    Science.gov (United States)

    Laaksonen, Marko S; Heinonen, Ilkka; Luotolahti, Matti; Knuuti, Juhani; Kalliokoski, Kari K

    2014-08-01

    Endurance training induces cardiovascular and metabolic adaptations, leading to enhanced endurance capacity and exercise performance. Previous human studies have shown contradictory results in functional myocardial vascular adaptations to exercise training, and we hypothesized that this may be related to different degrees of hypertrophy in the trained heart. We studied the interrelationships between peak aerobic power (V˙O2peak), myocardial blood flow (MBF) at rest and during adenosine-induced vasodilation, and parameters of myocardial hypertrophy in endurance-trained (ET, n = 31) and untrained (n = 17) subjects. MBF and myocardial hypertrophy were studied using positron emission tomography and echocardiography, respectively. Both V˙O2peak (P negatively with adenosine-stimulated MBF, but when LV mass was taken into account as a partial correlate, this correlation disappeared. The present results show that increased LV mass in ET subjects explains the reduced hyperemic myocardial perfusion in this subject population and suggests that excessive LV hypertrophy has negative effect on cardiac blood flow capacity.

  14. A quantitative index of regional blood flow in canine myocardium derived noninvasively with N-13 ammonia and dynamic positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nienaber, C.A.; Ratib, O.; Gambhir, S.S.; Krivokapich, J.; Huang, S.C.; Phelps, M.E.; Schelbert, H.R. (Univ. of California, Los Angeles School of Medicine (USA))

    1991-01-01

    To derive a quantitative index of regional myocardial blood flow, the arterial input function of the flow tracer N-13 ammonia and the regional myocardial N-13 activity concentrations were noninvasively determined in 29 experiments in eight dogs. N-13 ammonia was administered intravenously and cross-sectional images were acquired dynamically using an ECAT III positron emission tomograph with an effective in-plane resolution of 13.46 mm full-width half-maximum. Time-activity curves were derived from the serial images by assigning regions of interest to the left ventricular myocardium and left ventricular blood pool. Tracer net extractions were estimated from the myocardial time-activity concentrations at various times after tracer injection and the integral of the arterial input function. Myocardial blood flow was altered by intravenous dipyridamole, morphine, propranolol and partial or complete occlusion of the left anterior descending coronary artery, and ranged from 9 to 860 ml/min per 100 g. Estimates of tracer net extractions were most accurate when determined from the myocardial N-13 activity concentrations at 60 s divided by the integral of the arterial input function to that time. These estimates correlated with regional myocardial blood flows determined independently by the microsphere technique by y = x (1 - 0.64(e-114/x); SEE = 22.9; r = 0.94). First pass extraction fractions of N-13 ammonia determined noninvasively with this approach declined with higher flows in a nonlinear fashion and were similar to those determined invasively by direct intracoronary N-13 ammonia injections. The findings indicate that an accurate index of regional myocardial blood flow can be obtained noninvasively by high temporal sampling of arterial and myocardial tracer activity concentrations with positron emission tomography.

  15. Myocardial study with rubidium-82 using positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    De Landsheere, C.; Brihaye, C.; Chevigne, M.; Guillaume, M.; Lamotte, D.; Larock, M.P.; Quaglia, L.; Rigo, P. (Universite de Liege (Belgium))

    1982-01-01

    The rubidium-82 is eluted from a strontium-82/rubidium-82 generator. Its short half-life (78 sec.) enables the sequential repetition of dynamic studies. Myocardial ischemia produced in the dog by a stenosis of the left anterior descending artery is investigated. In this case, intravenous administration of rubidium demonstrates a decrease in the cation uptake in the anterior wall of the left ventricle. Through ischemia studies various parameters which are liked to modify the rubidium distribution according to the equation describing the cation exchanges, are considered. The generator strontium-82/rubidium-82 delivers a reference tracer for myocardial flow evaluation without requiring a cyclotron which is then available for the direct production of metabolic tracers.

  16. Flow-rate measurement using radioactive tracers and transit time method

    International Nuclear Information System (INIS)

    Turtiainen, Heikki

    1986-08-01

    The transit time method is a flow measurement method based on tracer techniques. Measurement is done by injecting to the flow a pulse of tracer and measuring its transit time between two detection positions. From the transit time the mean flow velosity and - using the pipe cross section area - the volume flow rate can be calculated. When a radioisotope tracer is used the measurement can be done from outside the pipe and without disturbing the process (excluding the tracer injection). The use of the transit time method has been limited because of difficulties associated with handling and availability of radioactive tracers and lack of equipment suitable for routine use in industrial environments. The purpose of this study was to find out if these difficulties may be overcome by using a portable isotope generator as a tracer source and automating the measurement. In the study a test rig and measuring equipment based on the use of a ''1''3''7Cs/''1''3''7''''mBa isotope generator were constructed. They were used to study the accuracy and error sources of the method and to compare different algorithms to calculate the transit time. The usability of the method and the equipment in industrial environments were studied by carrying out over 20 flow measurements in paper and pulp mills. On the basis of the results of the study, a project for constructing a compact radiatracer flowmeter for industrial use has been started. The application range of this kind of meter is very large. The most obvious applications are in situ calibration of flowmeters, material and energy balance studies, process equipment analyses (e.g. pump efficiency analyses). At the moment tracer techniques are the only methods applicable to these measurements on-line and with sufficient accuracy

  17. Rubidium-82 PET-CT for quantitative assessment of myocardial blood flow: validation in a canine model of coronary artery stenosis

    International Nuclear Information System (INIS)

    Lautamaeki, Riikka; Higuchi, Takahiro; Merrill, Jennifer; Voicu, Corina; Bengel, Frank M.; George, Richard T.; Kitagawa, Kakuya; DiPaula, Anthony; Lima, Joao A.C.; Nekolla, Stephan G.; Lardo, Albert C.

    2009-01-01

    Absolute quantification of myocardial blood flow expands the diagnostic potential of PET for assessment of coronary artery disease. 82 Rb has significantly contributed to increasing utilization of PET; however, clinical studies are still mostly analysed qualitatively. The aim of this study was to reevaluate the feasibility of 82 Rb for flow quantification, using hybrid PET-CT in an animal model of coronary stenosis. Nine dogs were prepared with experimental coronary artery stenosis. Dynamic PET was performed for 8 min after 82 Rb(1480-1850 MBq) injection during adenosine-induced vasodilation. Microspheres were injected simultaneously for reference flow measurements. CT angiography was used to determine the myocardial regions related to the stenotic vessel. Two methods for flow calculation were employed: a two-compartment model including a spill-over term, and a simplified retention index. The two-compartment model data were in good agreement with microsphere flow (y=0.84x+0.20; r=0.92, p 82 Rb. A simplified approach based on tracer retention is practicable in the physiological flow range. These results encourage further testing of the robustness and usefulness in the clinical context of cardiac hybrid imaging. (orig.)

  18. Characterization of 3-Dimensional PET Systems for Accurate Quantification of Myocardial Blood Flow.

    Science.gov (United States)

    Renaud, Jennifer M; Yip, Kathy; Guimond, Jean; Trottier, Mikaël; Pibarot, Philippe; Turcotte, Eric; Maguire, Conor; Lalonde, Lucille; Gulenchyn, Karen; Farncombe, Troy; Wisenberg, Gerald; Moody, Jonathan; Lee, Benjamin; Port, Steven C; Turkington, Timothy G; Beanlands, Rob S; deKemp, Robert A

    2017-01-01

    Three-dimensional (3D) mode imaging is the current standard for PET/CT systems. Dynamic imaging for quantification of myocardial blood flow with short-lived tracers, such as 82 Rb-chloride, requires accuracy to be maintained over a wide range of isotope activities and scanner counting rates. We proposed new performance standard measurements to characterize the dynamic range of PET systems for accurate quantitative imaging. 82 Rb or 13 N-ammonia (1,100-3,000 MBq) was injected into the heart wall insert of an anthropomorphic torso phantom. A decaying isotope scan was obtained over 5 half-lives on 9 different 3D PET/CT systems and 1 3D/2-dimensional PET-only system. Dynamic images (28 × 15 s) were reconstructed using iterative algorithms with all corrections enabled. Dynamic range was defined as the maximum activity in the myocardial wall with less than 10% bias, from which corresponding dead-time, counting rates, and/or injected activity limits were established for each scanner. Scatter correction residual bias was estimated as the maximum cavity blood-to-myocardium activity ratio. Image quality was assessed via the coefficient of variation measuring nonuniformity of the left ventricular myocardium activity distribution. Maximum recommended injected activity/body weight, peak dead-time correction factor, counting rates, and residual scatter bias for accurate cardiac myocardial blood flow imaging were 3-14 MBq/kg, 1.5-4.0, 22-64 Mcps singles and 4-14 Mcps prompt coincidence counting rates, and 2%-10% on the investigated scanners. Nonuniformity of the myocardial activity distribution varied from 3% to 16%. Accurate dynamic imaging is possible on the 10 3D PET systems if the maximum injected MBq/kg values are respected to limit peak dead-time losses during the bolus first-pass transit. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  19. The relationship between myocardial blood flow and myocardial viability after reperfusion. Myocardial viability assessed by 15O-water-PET

    International Nuclear Information System (INIS)

    Tsukagoshi, Joichi

    1994-01-01

    The purpose of this study was to examine the relationship between myocardial blood flow and myocardial viability in the ischemic canine myocardium after reperfusion. Transient ischemia was induced by 60-, 90-, and 180-minute occlusion of the left anterior descending coronary artery. Myocardial blood flow (MBF) was measured in the areas in which regional contractility was severely impaired (ehocardiographically akinetic or dyskinetic) in the early reperfusion period by 15 O-water positron emission tomography (PET) 12 hours and 4 weeks after reperfusion. An MBF ratio of ischemic to nonischemic regions 12 hours after reperfusion was inversely correlated with the amount of histologically determined tissue necrosis (r=-0.74). The regional contractility recovered 4 weeks later in the areas where an MBF ratio was 0.48 or greater, but did not recover in the areas with a lower MBF ratio. Thus, myocardial viability can be appropriately predicted in the early phase of myocardial perfusion by PET with 15 O-water even in the absence of metabolic imaging. (author)

  20. Use of tracers to quantify subsurface flow through a mining pit.

    Science.gov (United States)

    Schladow, S Geoffrey; Clark, Jordan F

    2008-12-01

    Three independent tracer experiments were conducted to quantify the through-flow of water from Herman Pit, an abandoned mercury (Hg) mine pit adjacent to Clear Lake, California, USA. The tracers used were Rhodamine-WT, sulfur hexafluoride, and a mixture of sulfur hexafluoride and neon-22. The tracers were injected into Herman Pit, a generally well-mixed water body of approximately 81,000 m2, and the concentrations were monitored in the mine pit, observation wells, and the lake for 2-3 months following each injection. The results for all three experiments showed that the tracer arrived at certain observation wells within days of injection. Comparing all the well data showed a highly heterogeneous response, with a small number of wells showing this near-instantaneous response and others taking months before the tracer was detectable. Tracer was also found in the lake on four occasions over a one-month period, too few to infer any pattern but sufficient to confirm the connection of the two water bodies. Using a simple mass balance model it was possible to determine the effective loss rate through advection for each of the tracers and with this to estimate the through-flow rate. The through-flow rate for all three experiments was approximately 630 L/s, at least 1-2 orders of magnitude larger than previous estimates, all of which had been based on geochemical inferences or other indirect measures of the pit through-flow.

  1. Diffusing passive tracers in random incompressible flows: Statistical topography aspects

    International Nuclear Information System (INIS)

    Klyatskin, V.I.; Woyczynski, W.A.; Gurarie, D.

    1996-01-01

    The paper studies statistical characteristics of the passive tracer concentrations and of its spatial gradient, in random incompressible velocity fields from the viewpoint of statistical topography. The statistics of interest include mean values, probability distributions, as well as various functionals characterizing topographic features of tracers. The functional approach is used. We consider the influence of the mean flow (the linear shear flow) and the molecular diffusion coefficient on the statistics of the tracer. Most of our analysis is carried out in the framework of the delta-correlated (in time) approximation and conditions for its applicability are established. But we also consider the diffusion approximation scheme for finite correlation radius. The latter is applied to a diffusing passive tracer that undergoes sedimentation in a random velocity field

  2. Measurement of radioactive tracer microsphere blood from with NaI(Tl)- and Ge-well type detectors

    International Nuclear Information System (INIS)

    Winkler, B.; Staemmler, G.; Schaper, W.; Frank, J.; Langsdorf, S.

    1982-01-01

    An intrinsic Ge-well type detector was applied for the detection of gamma rays from labeled tracer microspheres. The high energy resolution and the large peak-to-Compton ratio of this spectrometer ensures the application of all available differently labeled tracer microspheres in one experiment. The superior energy resolution of the Ge-detector was documented with the separated photopeak regions of 103-Ru and 85-Sr-labeled tracer microspheres, which result in a single photopeak when an NaI(Tl) detector is used. The Ge-well type detector was compared with an NaI(Tl) spectrometer by counting samples of cardiac muscle in either spectrometer systems. Regression analysis between both spectrometer systems demonstrate identical flow values in these samples for 5 differently labeled tracer microspheres which were administered in 5 dogs. The high sensitivity of the Ge-well-type detector together with a suitable technique for sampling of myocardial tissue accomplishes a high spatial resolution of myocardial perfusion for all available differently labeled tracer microspheres. (orig.)

  3. Quantitation of myocardial blood flow and myocardial flow reserve with {sup 99m}Tc-sestamibi dynamic SPECT/CT to enhance detection of coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Bailing [University of Missouri-Columbia, Nuclear Science and Engineering Institute, Columbia, MO (United States); Chen, Fu-Chung; Chen, Chien-Cheng [Show Chwan Memorial Hospital, Section of Cardiology, Department of Internal Medicine, Changhua (China); Wu, Tao-Cheng [Taipei Veterans General Hospital, Section of Cardiology, Department of Internal Medicine, Taipei (China); Huang, Wen-Sheng [Changhua Christian Hospital, Department of Medical Research and Department of Nuclear Medicine, Changhua (China); Hou, Po-Nien [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Lukong Town, Changhua Shien (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Lukong Town, Changhua Shien (China); Central Taiwan University of Science and Technology, Department of Medical Imaging and Radiological Science, Taichung (China); China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China)

    2014-12-15

    Conventional dual-head single photon emission computed tomography (SPECT)/CT systems capable of fast dynamic SPECT (DySPECT) imaging have a potential for flow quantitation. This study introduced a new method to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) with DySPECT scan and evaluated the diagnostic performance of detecting coronary artery disease (CAD) compared with perfusion using invasive coronary angiography (CAG) as the reference standard. This study included 21 patients with suspected or known CAD who had received DySPECT, ECG-gated SPECT (GSPECT), and CAG (13 with ≥50 % stenosis in any vessel; non-CAD group: 8 with patent arteries or <50 % stenosis). DySPECT and GSPECT scans were performed on a widely used dual-head SPECT/CT scanner. The DySPECT imaging protocol utilized 12-min multiple back-and-forth gantry rotations during injections of {sup 99m}Tc-sestamibi (MIBI) tracer at rest or dipyridamole-stress stages. DySPECT images were reconstructed with full physical corrections and converted to the physical unit of becquerels per milliliter. Stress MBF (SMBF), rest MBF (RMBF), and MFR were quantified by a one-tissue compartment flow model using time-activity curves derived from DySPECT images. Perfusion images were processed for GSPECT scan and interpreted to obtain summed stress score (SSS) and summed difference score (SDS). Receiver-operating characteristic (ROC) analyses were conducted to evaluate the diagnostic performance of flow and perfusion. Using the criteria of ≥50 % stenosis as positive CAD, areas under the ROC curve (AUCs) of flow assessment were overall significantly greater than those of perfusion. For patient-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.91 ± 0.07, 0.86 ± 0.09, 0.64 ± 0.12, and 0.59 ± 0.13. For vessel-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.81 ± 0.05, 0.76 ± 0.06, 0.62 ± 0.07, and 0.56 ± 0.08, respectively. The preliminary data suggest that MBF quantitation with a

  4. Effect of streptozotocin-induced diabetes on myocardial blood flow reserve assessed by myocardial contrast echocardiography in rats

    Directory of Open Access Journals (Sweden)

    Weytjens Caroline

    2008-09-01

    Full Text Available Abstract The role of structural and functional abnormalities of small vessels in diabetes cardiomyopathy remains unclear. Myocardial contrast echocardiography allows the quantification of myocardial blood flow at rest and during dipyridamole infusion. The aim of the study was to determine the myocardial blood flow reserve in normal rats compared with Streptozotocin-induced diabetic rats using contrast echocardiography. Methods We prospectively studied 40 Wistar rats. Diabetes was induced by intravenous streptozotocin in 20 rats. All rats underwent baseline and stress (dipyridamole: 20 mg/kg high power intermittent imaging in short axis view under anaesthesia baseline and after six months. Myocardial blood flow was determined and compared at rest and after dipyridamole in both populations. The myocardial blood flow reserve was calculated and compared in the 2 groups. Parameters of left ventricular function were determined from the M-mode tracings and histological examination was performed in all rats at the end of the study. Results At six months, myocardial blood flow reserve was significantly lower in diabetic rats compared to controls (3.09 ± 0.98 vs. 1.28 ± 0.67 ml min-1 g-1; p Conclusion In this animal study, diabetes induced a functional alteration of the coronary microcirculation, as demonstrated by contrast echocardiography, a decrease in capillary density and of the cardiac systolic function. These findings may offer new insights into the underlying mechanisms of diabetes cardiomyopathy.

  5. Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach

    Science.gov (United States)

    Abrantes, João R. C. B.; Moruzzi, Rodrigo B.; Silveira, Alexandre; de Lima, João L. M. P.

    2018-02-01

    The accurate measurement of shallow flow velocities is crucial to understand and model the dynamics of sediment and pollutant transport by overland flow. In this study, a novel triple-tracer approach was used to re-evaluate and compare the traditional and well established dye and salt tracer techniques with the more recent thermal tracer technique in estimating shallow flow velocities. For this purpose a triple tracer (i.e. dyed-salted-heated water) was used. Optical and infrared video cameras and an electrical conductivity sensor were used to detect the tracers in the flow. Leading edge and centroid velocities of the tracers were measured and the correction factors used to determine the actual mean flow velocities from tracer measured velocities were compared and investigated. Experiments were carried out for different flow discharges (32-1813 ml s-1) on smooth acrylic, sand, stones and synthetic grass bed surfaces with 0.8, 4.4 and 13.2% slopes. The results showed that thermal tracers can be used to estimate shallow flow velocities, since the three techniques yielded very similar results without significant differences between them. The main advantages of the thermal tracer were that the movement of the tracer along the measuring section was more easily visible than it was in the real image videos and that it was possible to measure space-averaged flow velocities instead of only one velocity value, with the salt tracer. The correction factors used to determine the actual mean velocity of overland flow varied directly with Reynolds and Froude numbers, flow velocity and slope and inversely with flow depth and bed roughness. In shallow flows, velocity estimation using tracers entails considerable uncertainty and caution must be taken with these measurements, especially in field studies where these variables vary appreciably in space and time.

  6. Myocardial metabolism of 123I-BMIPP during low-flow ischaemia in an experimental model: comparison with myocardial blood flow and 18F-FDG

    International Nuclear Information System (INIS)

    Hosokawa, Ryohei; Nohara, Ryuji; Hirai, Taku; Fujita, Masatoshi; Sasayama, Shigetake; Fujibayashi, Yasuhisa; Magata, Yasuhiro; Tadamura, Eiji; Konishi, Junji

    2001-01-01

    Risk stratification of coronary artery disease may provide a basis for selection of treatment to prevent myocardial events and to assist functional recovery. Iodine-123 (ρ-iodophenyl)-3-R,S-methylpentadecanoic acid ( 123 I-BMIPP) is a radioiodinated fatty acid analogue for single-photon emission tomographic (SPET) imaging, and several reports have demonstrated that the abnormal uptake of 123 I-BMIPP is associated with wall motion abnormality and severe coronary artery stenosis. Clarification of the contribution of fatty acids to myocardial metabolism would be highly valuable in recognising this critical condition. In this study, we investigated the myocardial uptake of 123 I-BMIPP under low-flow ischaemia, and compared it with the uptake of fluorine-18 fluorodeoxyglucose ( 18 F-FDG). Using open chest dogs, the flow of the left anterior descending coronary artery was controlled using a pneumatic occluder in order to maintain a 30%-40% reduction of Doppler flow. 123 I-BMIPP and 18 F-FDG were injected into the left atrium after 90 min of ischaemia (protocols 1 and 3). Canine hearts were excised after 120 min of ischaemia for the measurement of radioactivity. In protocol 2, 123 I-BMIPP alone was injected and hearts were excised 8 min after the injection. A time-course biopsy study was also performed at the same time (protocol 3). Wall thickening was evaluated using a wall tracker module. The uptake of 18 F-FDG increased significantly in the ischaemic region (232%±135% vs non-ischaemic, P 18 F-FDG did not correlate well with the severity of MBF. On the other hand, 123 I-BMIPP uptake decreased gradually (78.9%±23.6%, P 123 I-BMIPP was associated not only with wall motion abnormality but also with the severity of MBF. In the biopsy study (protocol 3), the radioactivity of either 123 I-BMIPP or 18 F-FDG correlated well with the MBF at the time of tracer injection and was similar to post-mortem analysis. It is concluded that 18 F-FDG is a valid tool for identifying

  7. Application of artificial radioactive tracers for groundwater flow

    International Nuclear Information System (INIS)

    Hamza, M.S.; Aly, A.I.M.; Swailem, F.M.; Nada, A.A.; Awad, M.A.

    1989-01-01

    In this work, the groundwater velocity was estimated by applying radioactive tracer techniques: the single well and the multiple well methods. In the first single well method, radioactive iodine-131 was injected in the well and the radioactivity was monitored with time. The groundwater flow was estimated as a function of the concentration dilution factor of the tracer taking into consideration the permeability of the filter screen and the aquifer. The second method (the multiple well technique) is based on direct measuring of the period of time the tracer needs to disperse from the injection well to one of receptor well arranged in a circle around the injection. The latter method was found to be more accurate and reliable and has also the advantage of determining the groundwater velocity and direction of flow as well. The limitations of the single well technique are discussed and a detailed comparison between single and multi-well techniques is given

  8. Myocardial imaging in the noninvasive evaluation of patients with suspected ischemic heart disease

    International Nuclear Information System (INIS)

    Pitt, B.; Strauss, H.W.

    1976-01-01

    Three noninvasive radioactive tracer techniques for evaluating patients with ischemic heart disease are described: (1) myocardial perfusion imaging, (2) acute infarct imaging, and (3) the gated blood pool scan. Myocardial perfusion imaging with tracers that distribute in the myocardium in relation to regional blood flow allows detection of patients with transmural and nontransmural infarction by the finding of decreased tracer concentration in the affected region of the myocardium. If these tracers are injected at the time of maximal stress to patients with significant coronary arterial stenosis but without infarction, areas of transient ischemia can be identified as zones of decreased tracer concentration not found when an examination is performed at rest. Acute infarct imaging with tracers that localize in acutely damaged tissue permits separation of patients with acute myocardial necrosis from those without infarction and those with more chronic damage. The gated blood pool scan permits assessment of left ventricular function and regional wall motion. The measurement of ventricular volumes, ejection fraction and regional wall motion adds significantly to the determination of hemodynamic variables in assessing patients with acute infarction. The technique also permits detection of right ventricular dysfunction. Performance of a combination of these radioactive tracer techniques is often advantageous, particularly in patients with suspected infarction. The techniques can establish whether infarction is present, whether it is acute, where the damage is located and how extensive it is; they can also provide a measure of the effect of this damage on left ventricular function

  9. Rubidium-82 PET-CT for quantitative assessment of myocardial blood flow: validation in a canine model of coronary artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Lautamaeki, Riikka; Higuchi, Takahiro; Merrill, Jennifer; Voicu, Corina; Bengel, Frank M. [Johns Hopkins Medical Institutions, Department of Radiology, Division of Nuclear Medicine, Baltimore, MD (United States); George, Richard T.; Kitagawa, Kakuya; DiPaula, Anthony; Lima, Joao A.C. [Johns Hopkins Medical Institutions, Department of Medicine, Division of Cardiology, Baltimore, MD (United States); Nekolla, Stephan G. [Technischen Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Munich (Germany); Lardo, Albert C. [Johns Hopkins Medical Institutions, Department of Medicine, Division of Cardiology, Baltimore, MD (United States); Johns Hopkins Medical Institutions, Department of Biomedical Engineering, Baltimore, MD (United States)

    2009-04-15

    Absolute quantification of myocardial blood flow expands the diagnostic potential of PET for assessment of coronary artery disease. {sup 82}Rb has significantly contributed to increasing utilization of PET; however, clinical studies are still mostly analysed qualitatively. The aim of this study was to reevaluate the feasibility of {sup 82}Rb for flow quantification, using hybrid PET-CT in an animal model of coronary stenosis. Nine dogs were prepared with experimental coronary artery stenosis. Dynamic PET was performed for 8 min after {sup 82}Rb(1480-1850 MBq) injection during adenosine-induced vasodilation. Microspheres were injected simultaneously for reference flow measurements. CT angiography was used to determine the myocardial regions related to the stenotic vessel. Two methods for flow calculation were employed: a two-compartment model including a spill-over term, and a simplified retention index. The two-compartment model data were in good agreement with microsphere flow (y=0.84x+0.20; r=0.92, p<0.0001), although there was variability in the physiological flow range <3 ml/g per minute (y=0.54x+0.53; r=0.53, p=0.042). Results from the retention index also correlated well with microsphere flow (y=0.47x+0.52; r=0.75, p=0.0004). Error increased with higher flow, but the correlation was good in the physiological range (y=0.62x+0.29; r=0.84, p=0.0001). Using current state-of-the-art PET-CT systems, quantification of myocardial blood flow is feasible with {sup 82}Rb. A simplified approach based on tracer retention is practicable in the physiological flow range. These results encourage further testing of the robustness and usefulness in the clinical context of cardiac hybrid imaging. (orig.)

  10. The relationship between myocardial blood flow and myocardial viability after reperfusion. Myocardial viability assessed by [sup 15]O-water-PET

    Energy Technology Data Exchange (ETDEWEB)

    Tsukagoshi, Joichi (Gunma Univ., Maebashi (Japan). School of Medicine)

    1994-09-01

    The purpose of this study was to examine the relationship between myocardial blood flow and myocardial viability in the ischemic canine myocardium after reperfusion. Transient ischemia was induced by 60-, 90-, and 180-minute occlusion of the left anterior descending coronary artery. Myocardial blood flow (MBF) was measured in the areas in which regional contractility was severely impaired (ehocardiographically akinetic or dyskinetic) in the early reperfusion period by [sup 15]O-water positron emission tomography (PET) 12 hours and 4 weeks after reperfusion. An MBF ratio of ischemic to nonischemic regions 12 hours after reperfusion was inversely correlated with the amount of histologically determined tissue necrosis (r=-0.74). The regional contractility recovered 4 weeks later in the areas where an MBF ratio was 0.48 or greater, but did not recover in the areas with a lower MBF ratio. Thus, myocardial viability can be appropriately predicted in the early phase of myocardial perfusion by PET with [sup 15]O-water even in the absence of metabolic imaging. (author).

  11. Tracer concentration curves and residence time analysis in technological flow systems. 2

    International Nuclear Information System (INIS)

    Pippel, W.

    1976-01-01

    Tracer concentration curves measured in flow systems by means of radioactive isotopes are treated as a two dimensional random process. Comparing them with the family distribution functions described in part I, it follows that only in case of ergodic behaviour of the system tracer curves can be considered as age distribution functions. The conception of ergodicity in residence time systems has been explained with the aid of a time function measurable by a special method of radioactive tracer technique and by the mean value of the residence time obtainable from this function. Furthermore, technological consequences in evaluating tracer concentration curves of real flow systems are discussed with respect to supposed ergodic or nonergodic behaviour. These considerations are of special importance for flow systems with temporary fluctuations in structure. (author)

  12. Radioiodinated tracers for myocardial imaging

    International Nuclear Information System (INIS)

    Kulkarni, P.V.; Corbett, J.R.

    1990-01-01

    Recent advances in the efficient production of high purity radioiodine (123I) and new efficient radiolabeling techniques have allowed the development of new classes of cardiovascular radiopharmaceuticals. These include 123I-labeled fatty acids to assess myocardial metabolism, 123I-metaiodobenzylguanidine (MIBG) for myocardial neuronal activity, labeled monoclonal antibodies for myocardial necrosis, and labeled lipoproteins for receptor concentration. 123I-labeled fatty acids and MIBG are under clinical investigation with encouraging results. 123I- and 111In-labeled fragments of monoclonal antibodies to myosin have been used for imaging myocardial necrosis in humans. The development of radiotracers for imaging of cholinergic and adrenergic receptors is still in the experimental stage. Recent advances in imaging instrumentation and radiopharmaceuticals have resulted in cardiac imaging applications beyond blood pool ventriculography, perfusion, and infarct-avid imaging. Developments of radioiodine (123I)-labeled agents promise to play an important role in the assessment of myocardial metabolism, neuronal activity, and receptor concentration. The chemistry of iodine is well defined compared with that of 99mTc; therefore, iodine isotopes are well suited for labeling biologically important molecules. Among the iodine isotopes, 123I has nearly ideal nuclear properties for nuclear medical applications with a 13.3-hour half-life (T1/2) and 159 keV gamma emission (83%). Despite the nearly ideal chemical and nuclear properties of 123I, the widespread application of 123I-based radiopharmaceuticals in clinical practice has been limited by high production costs (123I is produced in a cyclotron), relatively limited availability, and the presence of undesirable radionuclidic impurities (124I, T1/2 = 4.2 days; 125I, T1/2 = 60 days; 126I, T1/2 = 13.1 days). 77 references

  13. PET imaging of angiogenesis after myocardial infarction/reperfusion using a one-step labeled integrin-targeted tracer {sup 18}F-AlF-NOTA-PRGD2

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Haokao [The Fourth Military Medical University, Department of Cardiology, Xijing Hospital, Xi' an (China); National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Laboratory of Molecular Imaging and Nanomedicine (LOMIN), Bethesda, MD (United States); Lang, Lixin; Guo, Ning; Quan, Qimeng; Hu, Shuo; Kiesewetter, Dale O.; Niu, Gang; Chen, Xiaoyuan [National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Laboratory of Molecular Imaging and Nanomedicine (LOMIN), Bethesda, MD (United States); Cao, Feng [The Fourth Military Medical University, Department of Cardiology, Xijing Hospital, Xi' an (China)

    2012-04-15

    The {alpha}{sub v}{beta}{sub 3} integrin represents a potential target for noninvasive imaging of angiogenesis. The purpose of this study was to evaluate a novel one-step labeled integrin {alpha}{sub v}{beta}{sub 3}-targeting positron emission tomography (PET) probe, {sup 18}F-AlF-NOTA-PRGD2, for angiogenesis imaging in a myocardial infarction/reperfusion (MI/R) animal model. Male Sprague-Dawley rats underwent 45-min transient left coronary artery occlusion followed by reperfusion. The myocardial infarction was confirmed by ECG, {sup 18}F-fluorodeoxyglucose (FDG) imaging, and cardiac ultrasound. In vivo PET imaging was used to determine myocardial uptake of {sup 18}F-AlF-NOTA-PRGD2 at different time points following reperfusion. The control peptide RAD was labeled with a similar procedure and used to confirm the specificity. Ex vivo autoradiographic analysis and CD31/CD61 double immunofluorescence staining were performed to validate the PET results. Myocardial origin of the {sup 18}F-AlF-NOTA-PRGD2 accumulation was confirmed by {sup 18}F-FDG and autoradiography. PET imaging demonstrated increased focal accumulation of {sup 18}F-AlF-NOTA-PRGD2 in the infarcted area which started at day 3 (0.28 {+-} 0.03%ID/g, p < 0.05) and peaked between 1 and 3 weeks (0.59 {+-} 0.16 and 0.55 {+-} 0.13%ID/g, respectively). The focal accumulation decreased but still kept at a higher level than the sham group after 4 months of reperfusion (0.31 {+-} 0.01%ID/g, p < 0.05). Pretreatment with unlabeled arginine-glycine-aspartic acid (RGD) peptide significantly decreased tracer uptake, indicating integrin specificity of this tracer. At 1 week after MI/R, uptake of the control tracer {sup 18}F-AlF-NOTA-RAD that does not bind to integrin, in the infarcted area, was only 0.21 {+-} 0.01%ID/g. Autoradiographic imaging showed the same trend of uptake in the myocardial infarction area. The time course of focal tracer uptake was consistent with the pattern of vascular density and integrin {beta

  14. Evaluation in dogs of a new double-dose technique for imaging changes in myocardial perfusion

    International Nuclear Information System (INIS)

    Rothendler, J.A.; Okada, R.D.; Strauss, H.W.; Chesler, D.A.; Pohost, G.M.

    1984-01-01

    Assessment of myocardial perfusion with thallium immediately before and after an intervention that alters blood flow has been difficult due to presence of residual activity from the first tracer dose at the time of the second imaging. In a canine model the authors investigated a technique using two separate thallium injections during an intervention and after its reversal. Images were obtained after each injection, and a difference image was obtained by subtracting the first from the second image to correct for tracer persisting from the first injection. Interventions on coronary blood flow included: transient occlusion, subcritical stenosis with dipyridamole infusion, and permanent occlusion. The first images showed defects corresponding to the occlusion or stenosis, while the ''difference'' images correlated with myocardial perfusion at the time of the second injection

  15. Nuclear medicine and coronary artery disease: evaluation of tracers of myocardial perfusion and vulnerable atherosclerotic plaque; Medecine nucleaire et maladie coronarienne: evaluation de traceurs de la perfusion myocardique et de la plaque d'atherome vulnerable

    Energy Technology Data Exchange (ETDEWEB)

    Broisat, A

    2005-04-15

    Coronary artery disease is one of the primary cause of mortality worldwide. Nuclear medicine is the major imaging technique for diagnosis and following of this disease. perfusion: nowadays, major radioactive agents used in clinical practice are myocardial perfusion tracers. The reference tracer is thallium-201. However, {sup 201}Tl presents some drawbacks. {sup 99m}Tcn-noet has been proposed for its replacement. This study shows that in contrast with previous studies realized in vitro on cardio myocytes, verapamil, an l-type calcium channel inhibitor, does not inhibit myocardial fixation of {sup 99m}Tcn-noet in vivo in dog. This data is in agreement with the hypothesis of a non specific endothelial fixation of this tracer. Moreover, this study shows that as a pure tracer of myocardial perfusion, {sup 99m}Tcn-noet can also be used to assess myocardial viability on a model of myocardial chronic infarction in rat. atherosclerosis: disruption of vulnerable atherosclerotic plaques is the main event leading to coronary accidents. The second part of this study concerns the evaluation of new potential tracers of the vulnerable atherosclerotic plaque in an experimental model of rabbit with an inheritable hypercholesterolemia. The four tracers evaluated (b2702(r), b2702-I, b2702-Tc and Tc-raft-b2702) are synthetic peptides comprising the residues 75-84 of hla-b2702, a molecule known to link vcam-1, an adhesion molecule expressed in vulnerable atherosclerotic plaque. The autoradiography studies show that all tracers accumulate within atherosclerotic plaque expressing vcam- and that. i-b2702 shows the best plaque/control fixation ratio. (author)

  16. Effect of collateral circulation on myocardial protection in patients with acute myocardial infarction. Comparison of technetium-99m-tetrofosmin myocardial single photon emission computed tomography and coronary angiography

    International Nuclear Information System (INIS)

    Yoshida, Michi; Kondo, Makoto; Abe, Yoshiteru; Kubota, Tomoyuki; Matsuoka, Ryota; Araki, Makoto; Tanio, Hitoshi; Doyama, Kiyoshi

    2006-01-01

    Evaluation of myocardial blood flow from collateral vessels into the infarct area has been estimated by coronary angiography. In patients with acute myocardial infarction with Thrombolysis in Myocardial Infarction (TIMI) 0 flow, myocardial tracer uptake on single photon emission computed tomography (SPECT) images can predict the collateral blood flow in the infarct area if technetium (Tc)-99m-tetrofosmin was administered before recanalization. The present study investigated whether collateral blood flow evaluated by myocardial scintigraphy is a good predictor of myocardial salvage in patients with acute myocardial infarction. The study group consisted of 30 patients (mean age 65±14 years, 23 males, 7 females) with first acute myocardial infarction and coronary angiography evidence of total occlusion (TIMI 0) within 12 hr after the onset. All patients had one vessel disease related to infarction and TIMI 3 flow after percutaneous coronary intervention (PCI). Tc-99m-tetrofosmin was injected intravenously before the PCI. The regional severity score index (RSSI) was obtained from SPECT using the 17 segment method with the four-point scoring system. Myocardial viability was evaluated by the RSSI obtained from thallium-glucose-insulin infusion SPECT after 1 week and regional wall motion score index obtained from echocardiography during the chronic phase. The patients were divided into two groups according to the angiographic collateral finding. There were no differences in RSSI on thallium-glucose-insulin SPECT and regional wall motion score between the good collateral group (n=8) and poor collateral group (n=22). Myocardial Tc-99m-tetrofosmin RSSI was similar in these groups. On the other hand, the patients were divided according to Tc-99m-tetrofosmin scintigraphic evaluation before PCI. RSSI on thallium-glucose-insulin SPECT was significantly greater (0.7±0.5 vs 1.5±0.4, p<0.01) and regional wall motion score was significantly less (1.46±0.50 vs 2.08±0.78, p<0

  17. Nuclear medicine and coronary artery disease: evaluation of tracers of myocardial perfusion and vulnerable atherosclerotic plaque; Medecine nucleaire et maladie coronarienne: evaluation de traceurs de la perfusion myocardique et de la plaque d'atherome vulnerable

    Energy Technology Data Exchange (ETDEWEB)

    Broisat, A

    2005-04-15

    Coronary artery disease is one of the primary cause of mortality worldwide. Nuclear medicine is the major imaging technique for diagnosis and following of this disease. perfusion: nowadays, major radioactive agents used in clinical practice are myocardial perfusion tracers. The reference tracer is thallium-201. However, {sup 201}Tl presents some drawbacks. {sup 99m}Tcn-noet has been proposed for its replacement. This study shows that in contrast with previous studies realized in vitro on cardio myocytes, verapamil, an l-type calcium channel inhibitor, does not inhibit myocardial fixation of {sup 99m}Tcn-noet in vivo in dog. This data is in agreement with the hypothesis of a non specific endothelial fixation of this tracer. Moreover, this study shows that as a pure tracer of myocardial perfusion, {sup 99m}Tcn-noet can also be used to assess myocardial viability on a model of myocardial chronic infarction in rat. atherosclerosis: disruption of vulnerable atherosclerotic plaques is the main event leading to coronary accidents. The second part of this study concerns the evaluation of new potential tracers of the vulnerable atherosclerotic plaque in an experimental model of rabbit with an inheritable hypercholesterolemia. The four tracers evaluated (b2702(r), b2702-I, b2702-Tc and Tc-raft-b2702) are synthetic peptides comprising the residues 75-84 of hla-b2702, a molecule known to link vcam-1, an adhesion molecule expressed in vulnerable atherosclerotic plaque. The autoradiography studies show that all tracers accumulate within atherosclerotic plaque expressing vcam- and that. i-b2702 shows the best plaque/control fixation ratio. (author)

  18. Deuterium used as artificial tracer in column studies under saturated water flow conditions

    Science.gov (United States)

    Koeniger, P.; Geiges, M.; Leibundgut, Ch.

    2003-04-01

    In contrast to numerous investigations using deuterium as an environmental tracer, hydrological investigations with deuterium-labelled water are rather rare. Currently applications in groundwater studies are restricted due to increasing costs of spiking large water quantities but an application as intelligent tracer might be of advantage especially in combination with other tracers and under distinct environmental conditions. Therefore deuterium was applied as artificial tracer in column experiments that are well proved as a tool to characterise tracer behaviour in recent studies. Deuterium was tested in comparison to the more familiar conservative tracer fluorescein. Varying experimental conditions, e.g. column length (0.5, 1.0, 1.5 m), initial tracer concentration (0.01, 0.02, 0.2 mg) and flow velocity (1.5 to 6.0 m/d) were used to investigate tracer behaviour under saturated water flow conditions. Deuterium was analysed using an H/Device with chrome reduction connected to an isotope ratio mass spectrometer and expressed in relative concentrations [per mill V-SMOW]. Theoretical tracer breakthrough curves were calculated using a one dimensional dispersion model. The results indicate higher mean transport velocities and smaller dispersion for deuterium in all experiments. Due to different molecule properties that also determine the interaction of soil substrate and tracer, deuterium indicates a more conservative transport behaviour. Deuterium is non-toxic, completely soluble, chemically and biologically stable and not subject to light-influenced decay. Furthermore, it shows promise for investigations of water flow in the unsaturated zone, and of interactions of water in soil-plant-atmosphere systems. A further discussion of problems, together with possibilities for applying deuterium as an artificial tracer, will be presented.

  19. Influence of pre-infarction angina, collateral flow, and pre-procedural TIMI flow on myocardial salvage index by cardiac magnetic resonance in patients with ST-segment elevation myocardial infarction

    DEFF Research Database (Denmark)

    Lønborg, Jacob Thomsen; Kelbæk, Henning Skov; Vejlstrup, Niels Grove

    2012-01-01

    BACKGROUND: In patients with ST-segment elevation myocardial infarction (STEMI) pre-infarction angina, pre-procedural TIMI flow and collateral flow to the myocardium supplied by the infarct related artery are suggested to be cardioprotective. We evaluated the effect of these factors on myocardial...

  20. Effects of respiratory alkalosis and acidosis on myocardial blood flow and metabolism in patients with coronary artery disease.

    Science.gov (United States)

    Kazmaier, S; Weyland, A; Buhre, W; Stephan, H; Rieke, H; Filoda, K; Sonntag, H

    1998-10-01

    Variation of the arterial carbon dioxide partial pressure (PaCO2) is not uncommon in anesthetic practice. However, little is known about the myocardial consequences of respiratory alkalosis and acidosis, particularly in patients with coronary artery disease. The aim of the current study was to investigate the effects of variation in PaCO2 on myocardial blood flow (MBF), metabolism, and systemic hemodynamics in patients before elective coronary artery bypass graft surgery. In 10 male anesthetized patients, measurements of MBF, myocardial contractility, metabolism, and systemic hemodynamics were made in a randomized sequence at PaCO2 levels of 30, 40, and 50 mmHg, respectively. The MBF was measured using the Kety-Schmidt technique with argon as a tracer. End-diastolic left ventricular pressure and the maximal increase of left ventricular pressure were assessed using a manometer-tipped catheter. The cardiac index significantly changed with varying PaCO2 levels (hypocapnia, - 9%; hypercapnia, 13%). This reaction was associated with inverse changes in systemic vascular resistance index levels. The MBF significantly increased by 15% during hypercapnia, whereas no change was found during hypocapnia. Myocardial oxygen and glucose uptake and the maximal increase of left ventricular pressure were not affected by varying PaCO2 levels. In anesthetized patients with coronary artery disease, short-term variations in PaCO2 have significant effects on MBF but do not influence global myocardial oxygen and glucose uptake. Changes in systemic hemodynamics associated with respiratory alkalosis and acidosis are caused by changes in systemic vascular resistance rather than by alterations in myocardial contractility.

  1. The use of tracer techniques to measure water flow rates in steam turbines

    International Nuclear Information System (INIS)

    Whitfield, O.J.; Blaylock, G.; Gale, R.W.

    1979-01-01

    Radioactive and chemical tracers offer some unique advantages in detailed flow measurement on steam turbine plant. A series of experiments on a nuclear power station are reported where tracers successfully measured water flow rates and the initial steam moisture with an accuracy suitable for performance and commissioning tests. Both radioactive and chemical tracer methods produced identical results. Straightforward practical procedures were evolved that ensured repeatable accuracy and in addition a quantitative method of detecting heater leaks on load was established. (author)

  2. Rapid dual-tracer PTSM+ATSM PET imaging of tumour blood flow and hypoxia: a simulation study

    International Nuclear Information System (INIS)

    Rust, T C; Kadrmas, D J

    2006-01-01

    Blood flow and hypoxia are interrelated aspects of physiology that affect cancer treatment and response. Cu-PTSM and Cu-ATSM are related PET tracers for blood flow and hypoxia, and the ability to rapidly image both tracers in a single scan would bring several advantages over conventional single-tracer techniques. Using dynamic imaging with staggered injections, overlapping signals for multiple PET tracers may be recovered utilizing information from kinetics and radioactive decay. In this work, rapid dual-tracer PTSM+ATSM PET was simulated and tested as a function of injection delay, order and relative dose for several copper isotopes, and the results were compared relative to separate single-tracer data. Time-activity curves representing a broad range of tumour blood flow and hypoxia levels were simulated, and parallel dual-tracer compartment modelling was used to recover the signals for each tracer. The main results were tested further using a torso phantom simulation of PET tumour imaging. Using scans as short as 30 minutes, the dual-tracer method provided measures of blood flow and hypoxia similar to single-tracer imaging. The best performance was obtained by injecting PTSM first and using a somewhat higher dose for ATSM. Comparable results for different copper isotopes suggest that tracer kinetics with staggered injections play a more important role than radioactive decay in the signal separation process. Rapid PTSM+ATSM PET has excellent potential for characterizing both tumour blood flow and hypoxia in a single, fast scan, provided that technological hurdles related to algorithm development and routine use can be overcome

  3. Effect of glucose and insulin infusion on the myocardial extraction of a radioiodinated methyl-substituted fatty acid

    International Nuclear Information System (INIS)

    Bianco, J.A.; Elmaleh, D.R.; Leppo, J.A.; King, M.A.; Moring, A.; Livni, E.; Espinoza, E.; Alpert, J.S.; Strauss, H.W.; Massachusetts General Hospital, Boston

    1986-01-01

    We investigated the one-way. An extraction of 14-iodophenyl-tetradecanoic acid (BMTDA) in the canine heart under fasting conditions and during infusion of glucose plus insulin in eight an esthetized greyhound dogs. Myocardial extraction measurements were made with dual tracer approach, using Tc-99m albumin as reference tracer. Prior to, and during, infusion of 10% glucose and 25 units of regular insulin, heart rate, blood pressure, plasma glucose, insulin and free fatty acid levels were measured. Myocardial blood flow was determined using Sn-113 and Ru-103 radioactive microspheres. The mean extraction fraction of BMTDA was 0.38+-SEM 0.06 at baseline and increased to 0.44+-0.06 during hyperglycemia plus insulin (P<0.025). Plasma glucose and insulin were higher during the infusion (P<0.01) while plasma free fatty acids significantly declined (P<0.01). There were no changes in hemodynamics or myocardial blood flow during the infusion. We conclude that glucose and insulin infusion result in increased first-pass extraction fraction of radioiodinated BMTDA unaccompanied by changes in coronary flow or hemodynamics, implying an insulin-mediated augmented transport of BMTDA. (orig.)

  4. Dynamic interaction between myocardial contraction and coronary flow.

    Science.gov (United States)

    Beyar, R; Sideman, S

    1997-01-01

    Phasic coronary flow is determined by the dynamic interaction between central hemodynamics and myocardial and ventricular mechanics. Various models, including the waterfall, intramyocardial pump and myocardial structural models, have been proposed for the coronary circulation. Concepts such as intramyocardial pressure, local elastance and others have been proposed to help explain the coronary compression by the myocardium. Yet some questions remain unresolved, and a new model has recently been proposed, linking a muscle collagen fibrous model to a physiologically based coronary model, and accounting for transport of fluids across the capillaries and lymphatic flow between the interstitial space and the venous system. One of the unique features of this model is that the intramyocardial pressure (IMP) in the interstitial space is calculated from the balance of forces and fluid transport in the system, and is therefore dependent on the coronary pressure conditions, the myocardial function and the transport properties of the system. The model predicts a wide range of experimentally observed phenomena associated with coronary compression.

  5. Sequential topographical portrayal of myocardial blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Richeson, J.F.; Waag, R.C.; Zwierzynski, D.; Schenk, E.A. (Univ. of Rochester School of Medicine and Dentistry, NY (USA))

    1989-08-01

    Methods to portray myocardial blood flow in a two-dimensional continuum are advantageous in that they allow blood flow history to be overlaid on histological or histochemical descriptions of the consequences of ischemia. We describe here autoradiographic methods that allow such portrayals at three separate times during the evolution of ischemic injury. A computer-based image-analysis system was used to derive such flow maps by taking advantage of the physical characteristics of radioactive isotopes.

  6. Synthesis and preliminary evaluation of 18F-labeled 4-thia palmitate as a PET tracer of myocardial fatty acid oxidation

    International Nuclear Information System (INIS)

    DeGrado, Timothy R.; Wang Shuyan; Holden, James E.; Nickles, R. Jerome; Taylor, Michael; Stone, Charles K.

    2000-01-01

    Interest remains strong for the development of a noninvasive technique for assessment of regional fatty acid oxidation rate in the myocardium. 18 F-labeled 4-thia palmitate (FTP, 16-[ 18 F]fluoro-4-thia-hexadecanoic acid) has been synthesized and preliminarily evaluated as a metabolically trapped probe of myocardial fatty acid oxidation for positron emission tomography (PET). The radiotracer is synthesized by Kryptofix 2.2.2/K 2 CO 3 assisted nucleophilic radiofluorination of an iodo-ester precursor, followed by alkaline hydrolysis and by purification by reverse phase high performance liquid chromatography. Biodistribution studies in rats showed high uptake and long retention of FTP in heart, liver, and kidneys consistent with relatively high fatty acid oxidation rates in these tissues. Inhibition of carnitine palmitoyl-transferase-I caused an 80% reduction in myocardial uptake, suggesting the dependence of trapping on the transport of tracer into the mitochondrion. Experiments with perfused rat hearts showed that the estimates of the fractional metabolic trapping rate (FR) of FTP tracked inhibition of oxidation rate of palmitate with hypoxia, whereas the FR of the 6-thia analog 17-[ 18 F]fluoro-6-thia-heptadecanoic acid was insensitive to hypoxia. In vivo defluorination of FTP in the rat was evidenced by bone uptake of radioactivity. A PET imaging study with FTP in normal swine showed excellent myocardial images, prolonged myocardial retention, and no bone uptake of radioactivity up to 3 h, the last finding suggesting a species dependence for defluorination of the omega-labeled fatty acid. The results support further investigation of FTP as a potential PET tracer for assessing regional fatty acid oxidation rate in the human myocardium

  7. Characterization of two-phase flow regimes in horizontal tubes using 81mKr tracer experiments.

    Science.gov (United States)

    Oriol, Jean; Leclerc, Jean Pierre; Berne, Philippe; Gousseau, Georges; Jallut, Christian; Tochon, Patrice; Clement, Patrice

    2008-10-01

    The diagnosis of heat exchangers on duty with respect to flow mal-distributions needs the development of non-intrusive inlet-outlet experimental techniques in order to perform an online fault diagnosis. Tracer experiments are an example of such techniques. They can be applied to mono-phase heat exchangers but also to multi-phase ones. In this case, the tracer experiments are more difficult to perform. In order to check for the capabilities of tracer experiments to be used for the flow mal-distribution diagnosis in the case of multi-phase heat exchangers, we present here a preliminary study on the simplest possible system: two-phase flows in a horizontal tube. (81m)Kr is used as gas tracer and properly collimated NaI (TI) crystal scintillators as detectors. The specific shape of the tracer response allows two-phase flow regimes to be characterized. Signal analysis allows the estimation of the gas phase real average velocity and consequently of the liquid phase real average velocity as well as of the volumetric void fraction. These results are compared successfully to those obtained with liquid phase tracer experiments previously presented by Oriol et al. 2007. Characterization of the two-phase flow regimes and liquid dispersion in horizontal and vertical tubes using coloured tracer and no intrusive optical detector. Chem. Eng. Sci. 63(1), 24-34, as well as to those given by correlations from literature.

  8. Characterization of two-phase flow regimes in horizontal tubes using 81mKr tracer experiments

    International Nuclear Information System (INIS)

    Oriol, Jean; Leclerc, Jean Pierre; Berne, Philippe; Gousseau, Georges; Jallut, Christian; Tochon, Patrice; Clement, Patrice

    2008-01-01

    The diagnosis of heat exchangers on duty with respect to flow mal-distributions needs the development of non-intrusive inlet-outlet experimental techniques in order to perform an online fault diagnosis. Tracer experiments are an example of such techniques. They can be applied to mono-phase heat exchangers but also to multi-phase ones. In this case, the tracer experiments are more difficult to perform. In order to check for the capabilities of tracer experiments to be used for the flow mal-distribution diagnosis in the case of multi-phase heat exchangers, we present here a preliminary study on the simplest possible system: two-phase flows in a horizontal tube. 81m Kr is used as gas tracer and properly collimated NaI (TI) crystal scintillators as detectors. The specific shape of the tracer response allows two-phase flow regimes to be characterized. Signal analysis allows the estimation of the gas phase real average velocity and consequently of the liquid phase real average velocity as well as of the volumetric void fraction. These results are compared successfully to those obtained with liquid phase tracer experiments previously presented by Oriol et al. 2007. Characterization of the two-phase flow regimes and liquid dispersion in horizontal and vertical tubes using coloured tracer and no intrusive optical detector. Chem. Eng. Sci. 63(1), 24-34, as well as to those given by correlations from literature

  9. Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, J.H.; Martin, G.V.; Link, J.M.; Krohn, K.A.; Bassingthwaighte, J.B. (Seattle VA Medical Center, WA (USA))

    1990-01-01

    Imaging {sup 123}I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, {sup 131}I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 {plus minus} 0.43) was similar to that for microspheres (0.94 {plus minus} 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal.

  10. Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion

    International Nuclear Information System (INIS)

    Caldwell, J.H.; Martin, G.V.; Link, J.M.; Krohn, K.A.; Bassingthwaighte, J.B.

    1990-01-01

    Imaging 123 I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, 131 I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 ± 0.43) was similar to that for microspheres (0.94 ± 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal

  11. Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion.

    Science.gov (United States)

    Caldwell, J H; Martin, G V; Link, J M; Krohn, K A; Bassingthwaighte, J B

    1990-01-01

    Imaging 123I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, 131I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 +/- 0.43) was similar to that for microspheres (0.94 +/- 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal.

  12. Evaluation of Parameter Uncertainty Reduction in Groundwater Flow Modeling Using Multiple Environmental Tracers

    Science.gov (United States)

    Arnold, B. W.; Gardner, P.

    2013-12-01

    Calibration of groundwater flow models for the purpose of evaluating flow and aquifer heterogeneity typically uses observations of hydraulic head in wells and appropriate boundary conditions. Environmental tracers have a wide variety of decay rates and input signals in recharge, resulting in a potentially broad source of additional information to constrain flow rates and heterogeneity. A numerical study was conducted to evaluate the reduction in uncertainty during model calibration using observations of various environmental tracers and combinations of tracers. A synthetic data set was constructed by simulating steady groundwater flow and transient tracer transport in a high-resolution, 2-D aquifer with heterogeneous permeability and porosity using the PFLOTRAN software code. Data on pressure and tracer concentration were extracted at well locations and then used as observations for automated calibration of a flow and transport model using the pilot point method and the PEST code. Optimization runs were performed to estimate parameter values of permeability at 30 pilot points in the model domain for cases using 42 observations of: 1) pressure, 2) pressure and CFC11 concentrations, 3) pressure and Ar-39 concentrations, and 4) pressure, CFC11, Ar-39, tritium, and He-3 concentrations. Results show significantly lower uncertainty, as indicated by the 95% linear confidence intervals, in permeability values at the pilot points for cases including observations of environmental tracer concentrations. The average linear uncertainty range for permeability at the pilot points using pressure observations alone is 4.6 orders of magnitude, using pressure and CFC11 concentrations is 1.6 orders of magnitude, using pressure and Ar-39 concentrations is 0.9 order of magnitude, and using pressure, CFC11, Ar-39, tritium, and He-3 concentrations is 1.0 order of magnitude. Data on Ar-39 concentrations result in the greatest parameter uncertainty reduction because its half-life of 269

  13. Synthesis and preliminary evaluation of {sup 18}F-labeled 4-thia palmitate as a PET tracer of myocardial fatty acid oxidation

    Energy Technology Data Exchange (ETDEWEB)

    DeGrado, Timothy R. E-mail: trd@petsparc.mc.duke.edu; Wang Shuyan; Holden, James E.; Nickles, R. Jerome; Taylor, Michael; Stone, Charles K

    2000-04-01

    Interest remains strong for the development of a noninvasive technique for assessment of regional fatty acid oxidation rate in the myocardium. {sup 18}F-labeled 4-thia palmitate (FTP, 16-[{sup 18}F]fluoro-4-thia-hexadecanoic acid) has been synthesized and preliminarily evaluated as a metabolically trapped probe of myocardial fatty acid oxidation for positron emission tomography (PET). The radiotracer is synthesized by Kryptofix 2.2.2/K{sub 2}CO{sub 3} assisted nucleophilic radiofluorination of an iodo-ester precursor, followed by alkaline hydrolysis and by purification by reverse phase high performance liquid chromatography. Biodistribution studies in rats showed high uptake and long retention of FTP in heart, liver, and kidneys consistent with relatively high fatty acid oxidation rates in these tissues. Inhibition of carnitine palmitoyl-transferase-I caused an 80% reduction in myocardial uptake, suggesting the dependence of trapping on the transport of tracer into the mitochondrion. Experiments with perfused rat hearts showed that the estimates of the fractional metabolic trapping rate (FR) of FTP tracked inhibition of oxidation rate of palmitate with hypoxia, whereas the FR of the 6-thia analog 17-[{sup 18}F]fluoro-6-thia-heptadecanoic acid was insensitive to hypoxia. In vivo defluorination of FTP in the rat was evidenced by bone uptake of radioactivity. A PET imaging study with FTP in normal swine showed excellent myocardial images, prolonged myocardial retention, and no bone uptake of radioactivity up to 3 h, the last finding suggesting a species dependence for defluorination of the omega-labeled fatty acid. The results support further investigation of FTP as a potential PET tracer for assessing regional fatty acid oxidation rate in the human myocardium.

  14. Clinical evaluation of 123I-BMIPP myocardial scintigraphy in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Ohtsuki, Katsuichi; Sugihara, Hiroki; Umamoto, Ikuo

    1992-01-01

    123 I-β-methyl-p-iodophenylpentadecanoic acid ( 123 I-BMIPP) myocardial scintigraphy was performed in 13 patients with hypertrophic cardiomyopathy and compared with 201 Tl myocardial scintigraphy performed within 3 months for evaluating the clinical significance of 123 I-BMIPP myocardial scintigraphy. SPECT images were divided into 13 segments and segmental images were visually scored on a 4 (increased tracer uptake) to 0 (severely decreased tracer uptake) scale according to the tracer uptake. In comparison of 123 I-BMIPP early images and 201 Tl perfusion images, mismatches were seen in about 70% of all segments. The number of segments demonstrating lower myocardial uptake of 123 I-BMIPP was larger than that of 201 Tl. In hypertrophic regions, the tracer uptake of 123 I-BMIPP early images was significantly lower than that of 201 Tl images and the lower uptake of 123 I-BMIPP delayed images was more marked. In non-hypertrophic regions, no significant difference was seen between the tracer uptakes of 123 I-BMIPP early images and 201 Tl images but the tracer uptake of 123 I-BMIPP delayed images was significantly lower than that of 201 Tl images. The mismatch between the tracer uptakes of 123 I-BMIPP images and 201 Tl images was thought to be a reflection of disordered myocardial fatty acid metabolism. 'Washout', the difference between the tracer uptakes of 123 I-BMIPP early images and delayed images was also thought to be a reflection of disordered myocardial fatty acid metabolism. These results suggest that 123 I-BMIPP is a promising radiopharmaceutical for evaluating disordered myocardial fatty acid metabolism in patients with HCM. (author)

  15. Tracer responses and control of vessels with variable flow and volume

    International Nuclear Information System (INIS)

    Niemi, A.J.

    1990-01-01

    Continuous flow vessels which are subject to variation of flow and volume are characterized by time-variable parameters. It is shown that their residence time distributions and weighting functions obtained by tracer testing are made invariant with regard to the integrated flow variables which are introduced. Under variable flow but constant volume, one such integrated variable is sufficient. Under variable volume, two different variables are suggested for the residence time distribution and weighting function, while the appropriate variable of the perfect mixer differs distinctly from that of vessels with a distinct velocity profile. It is shown through a number of example cases, that an agreement with their mathematical models is reached. The approach is extended to include also arbitrary, non-analytic response functions obtained by tracer measurements. Applications of the derived models and their incorporation in automatic control algorithms is discussed. (orig.) [de

  16. Technetium and rhenium complexes with modified fatty acid ligands 4. Evaluation of two new classes of 99mTc-labelled fatty acids as potential tracers for myocardial metabolism imaging

    International Nuclear Information System (INIS)

    Heintz, A.; Kropp, J.; Deussen, A.; Jung, C.M.; Spies, H.

    2002-01-01

    99m Tc-labelled fatty acids were synthesized according to the '3+1' mixed-ligand approach and investigated as potential tracers for myocardial SPECT diagnostics on the model of the isolated guinea pig heart. The results indicate a low but specific myocardial uptake of the 99m Tc fatty acid derivatives subject to chain length and structure. (orig.)

  17. Flow-rate measurements in closed-conduits by tracer techniques

    International Nuclear Information System (INIS)

    Lund Plantat, C.

    1982-01-01

    This paper presents the study of the precision obtained measuring flow-rates in closed-conduits by tracer techniques. The flow-rates analyzed were in the range of 10 to 20 l/s and Reynolds numbers from 10 5 to 2 x 10 5 . Tracer used were fluoresceine and In-113 m; and the measurements were performed with the dilution method (punctual and continuous injection) and the Allen method. Precisions for the method of punctual and continuous injections were 6.25% and 9.45% for fluoresceine and 9.3% and 3% for In-113, respectively. For Allen method with In-113 m a precision of 5% was obtained; probably this value was affected by the short distance between detectors. In all cases the error corresponds with the expected value except in one measurement at a 68.3% confidence level. (I.V.)

  18. Assessment of myocardial perfusion and metabolism for assessment of myocardial viability

    International Nuclear Information System (INIS)

    Beller, G.

    1996-01-01

    Identifying preserved myocardial viability in the presence of severe regional left ventricular dysfunction is becoming increasingly more important for clinical decision-making to better select those patients with coronary artery disease who will benefit most from revascularization. 201 Tl remains the most commonly employed radionuclide for detecting both ischemia and viability. A severe persistent defect with 201 Tl uptake compared to peak to improved perfusion and corresponding improved function after revascularisation. Detection of defect reversibility on 201 Tl imaging is enhanced by 'reinjection' of a second 201 Tl dose after acquisition of redistribution images. Initial and 4-hour rest/redistribution imaging has proven most usefull for detection of viability in the resting state in patients with ischemic cardiomyopathy. The greater the extent of preoperative viability, the greater is the improvement in regional and global function after revascularisation. 99 Tc sestamibi has also been demonstrated to be extracted by myocardial cells in proportion to regional blood flow in the presence of viable myocities. Although this agrnt does not redistribute after intravenous injection, its >50% uptake of the tracer implies viablility and predicts improved regional function after revascularisation. Finally positron emission tomography with 18 F fluorodeoxoglucose (FDG) is perhaps the most sensitive noninvasive imaging technique for detection of viability in stunned or hibernating myocardium. A mismatch pattern between regional flow and FDG uptake as approximately an 80-85% positive preicted value for predicting improved function in asynergic myocardial regions after revascualarisation

  19. Characterization of two-phase flow regimes in horizontal tubes using {sup 81m}Kr tracer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Oriol, Jean [LPAC, CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France); Leclerc, Jean Pierre [Laboratoire des Sciences du Genie Chimique (LSGC), Nancy-Universite, CNRS, BP 20451, F-54001 Nancy (France)], E-mail: leclerc@ensic.inpl-nancy.fr; Berne, Philippe; Gousseau, Georges [L2T, CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France); Jallut, Christian [Universite de Lyon, Universite Lyon 1, LAGEP, UMR CNRS 5007, ESCPE, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Tochon, Patrice; Clement, Patrice [GRETh, CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2008-10-15

    The diagnosis of heat exchangers on duty with respect to flow mal-distributions needs the development of non-intrusive inlet-outlet experimental techniques in order to perform an online fault diagnosis. Tracer experiments are an example of such techniques. They can be applied to mono-phase heat exchangers but also to multi-phase ones. In this case, the tracer experiments are more difficult to perform. In order to check for the capabilities of tracer experiments to be used for the flow mal-distribution diagnosis in the case of multi-phase heat exchangers, we present here a preliminary study on the simplest possible system: two-phase flows in a horizontal tube. {sup 81m}Kr is used as gas tracer and properly collimated NaI (TI) crystal scintillators as detectors. The specific shape of the tracer response allows two-phase flow regimes to be characterized. Signal analysis allows the estimation of the gas phase real average velocity and consequently of the liquid phase real average velocity as well as of the volumetric void fraction. These results are compared successfully to those obtained with liquid phase tracer experiments previously presented by Oriol et al. 2007. Characterization of the two-phase flow regimes and liquid dispersion in horizontal and vertical tubes using coloured tracer and no intrusive optical detector. Chem. Eng. Sci. 63(1), 24-34, as well as to those given by correlations from literature.

  20. PIV measurement of a contraction flow using micro-bubble tracer

    International Nuclear Information System (INIS)

    Ishikawa, Masaaki; Irabu, Kunio; Teruya, Isao; Nitta, Munehiro

    2009-01-01

    Recently, a technique using the micro-bubbles is focused. It was applied to many fields such as purification of rivers and lakes, washing the industrial parts, growth of plants and marine products. The characteristics of micro-bubbles are small size, wide surface area, low terminal velocity, and so on. If this micro-bubble is available as tracer of PIV (Particle Image Velocimetry), environment load would become lower because it doesn't need to discard particle. In this paper, we make a micro-bubble generator with Venturi type mechanism. The generated micro-bubbles are applied to a vertical channel flow with contraction. We validate about traceability of the micro-bubble tracer in comparison with the particle tracer.

  1. Reduced coronary flow and resistance reserve in primary scleroderma myocardial disease

    International Nuclear Information System (INIS)

    Nitenberg, A.; Foult, J.M.; Kahan, A.; Perennec, J.; Devaux, J.Y.; Menkes, C.J.; Amor, B.

    1986-01-01

    The maximum coronary vasodilator capacity after intravenous dipyridamole (0.14 mg X kg-1 X min-1 X 4 minutes) was studied in seven patients with primary scleroderma myocardial disease and compared to that of seven control subjects. Hemodynamic data and left ventricular angiographic data were not different in the two groups. The coronary flow reserve was evaluated by the dipyridamole/basal coronary sinus blood flow ratio (D/B CSBF) and the coronary resistance reserve by the dipyridamole/basal coronary resistance ratio (D/B CR). Coronary reserve was greatly impaired in the group with primary scleroderma myocardial disease: D/B CSBF was lower than in the control group (2.54 +/- 1.37 vs 4.01 +/- 0.56, respectively; p less than 0.05) and D/B CR was higher than in the control group (0.47 +/- 0.25 vs 0.23 +/- 0.04, respectively; p less than 0.05). Such a decreased coronary flow and resistance reserve in patients with primary scleroderma myocardial disease was not explained by an alteration of left ventricular function. It may be an important contributing factor in the pathogenesis of primary scleroderma myocardial disease

  2. Application of 123I-labelled long-chained fatty acids for the study of myocardial metabolism

    International Nuclear Information System (INIS)

    Freundlieb, C.; Hoeck, A.; Vyska, F.; Feinendegen, L.E.; Machulla, H.J.; Stoecklin, G.

    1978-01-01

    Radioiodine-labelled fatty acids are useful tracers for myocardial imaging. The present study extends myocardial scintigraphy with ω-123-I-heptadecanoic acid to measuring myocardial metabolism. 4 normal individuals and 6 patients with cardiac disease received i.v. 1-2 mCi ω-123-I-heptadecanoic acid. Immediately fast serial scintigrams of the myocardium were taken for 30 minutes. Disappearance of the tracer, and appearance of anorganic 123-I, was measured in the peripheral blood. The myocardial images were of high quality later than 5 minutes after injection. By correcting for anorganic 123-I in the peripheral blood and the interstitium, the turnover of tracer in the myocardial cells could be measured. Activity was lost from the myocardium with a half time between 14 and 32 minutes. Within regions of old myocardials infarctions the half time of tracer loss was prolonged. The data clearly indicate the feasibility of using ω-123-I-heptadecanoic acid for measuring myocardial metabolism. (author)

  3. Transport of pesticides and artificial tracers in vertical-flow lab-scale wetlands

    Science.gov (United States)

    Durst, Romy; Imfeld, Gwenaël.; Lange, Jens

    2013-01-01

    Wetland systems can be hydrologically connected to a shallow aquifer and intercept upward flow of pesticide-contaminated water during groundwater discharge. However, pesticide transport and attenuation through wetland sediments (WSs) intercepting contaminated water is rarely evaluated quantitatively. The use of artificial tracers to evaluate pesticide transport and associated risks is a fairly new approach that requires evaluation and validation. Here we evaluate during 84 days the transport of two pesticides (i.e., isoproturon (IPU) and metalaxyl (MTX)) and three tracers (i.e., bromide (Br), uranine (UR), and sulforhodamine B (SRB)) in upward vertical-flow vegetated and nonvegetated lab-scale wetlands. The lab-scale wetlands were filled with outdoor WSs and were continuously supplied with tracers and the pesticide-contaminated water. The transport of IPU and UR was characterized by high solute recovery (approximately 80%) and low retardation compared to Br. The detection of desmethylisoproturon in the wetlands indicated IPU degradation. SRB showed larger retardation (>3) and lower recovery (approximately 60%) compared to Br, indicating that sorption controlled SRB transport. MTX was moderately retarded (approximately 1.5), and its load attenuation in the wetland reached 40%. In the vegetated wetland, preferential flow along the roots decreased interactions between solutes and sediments, resulting in larger pesticide and tracer recovery. Our results show that UR and IPU have similar transport characteristics under the tested subsurface-flow conditions, whereas SRB may serve as a proxy for less mobile and more persistent pesticides. Since UR and SRB are not significantly affected by degradation, their use as proxies for fast degrading pollutants may be limited. We anticipate our results to be a starting point for considering artificial tracers for investigating pesticide transport in environments at groundwater/surface-water interfaces.

  4. The effects of hypoxemia on myocardial blood flow during exercise.

    Science.gov (United States)

    Paridon, S M; Bricker, J T; Dreyer, W J; Reardon, M; Smith, E O; Porter, C B; Michael, L; Fisher, D J

    1989-03-01

    We evaluated the adequacy of regional and transmural blood flow during exercise and rapid pacing after 1 wk of hypoxemia. Seven mature mongrel dogs were made hypoxemic (mean O2 saturation = 72.4%) by anastomosis of left pulmonary artery to left atrial appendage. Catheters were placed in the left atrium, right atrium, pulmonary artery, and aorta. Atrial and ventricular pacing wires were placed. An aortic flow probe was placed to measure cardiac output. Ten nonshunted dogs, similarly instrumented, served as controls. Recovery time was approximately 1 wk. Cardiac output, mean aortic pressure, and oxygen saturation were measured at rest, with ventricular pacing, atrial pacing, and with treadmill exercise. Ventricular and atrial pace and exercise were at a heart rate of 200. Right ventricular free wall, left ventricular free wall, and septal blood flow were measured with radionuclide-labeled microspheres. Cardiac output, left atrial blood pressure, and aortic blood pressure were similar between the two groups of dogs in all testing states. Myocardial blood flow was significantly higher in the right and left ventricular free wall in the hypoxemic animals during resting and exercise testing states. Myocardial oxygen delivery was similar between the two groups of animals. Pacing resulted in an increase in myocardial blood flow in the control animals but not the hypoxemic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Extraction and myocardial distribution of IPBDA potentials of lipophylic cations for use as thallium substitutes

    International Nuclear Information System (INIS)

    Rigo, P.; Woo, D.V.; Tanaka, T.; Wong, D.F.; Dannals, R.; Wagner, H.N. Jr.; Becker, L.C.

    1984-01-01

    Potassium analogs have been used for several years as clinical indicators of myocardial blood flow, but the value of thallium is limited by its long half life and low energy photons. We have tested 4-iodiphenylbenzyldimethylammonium (IPBDA) a radio-iodinated cation as a potential thallium substitute in a series of 7 mongrel dogs. First pass myocardial and systemic extraction were determined using the double tracer technique, with technetium albumin as reference. Tissue iodine 125 IPBDA distributions were compared to microspheres under a variety of pathophysiological conditions (control, myocardial infarction, coronary artery stenosis, Dipyridamole infusion). First pass extraction averaged 73% in normal controls (3 determinations), 66.1% in dogs with LAD occlusion (4 determination) and 40.1% in dogs receiving persantine (with or without coronary stenosis or occlusion) (5 determinations). Tissue microspheres and IPBDA distribution correlated in each dog (r=.75, to .85) but the relationship was not linear, IPBDA underestimating myocardial blood flow at high flow. Iodinated IPBDA is a potential thallium substitute due to the better physical characteristics of iodine 123. It shares however the biological limitations of potassium and analogs: a variable extraction and a non linear relation to flow. (Author)

  6. Study on the flow state of groundwater by isotope tracer

    International Nuclear Information System (INIS)

    Lin Tong; Chen Jiansheng; Chen Liang

    2008-01-01

    Radioisotope logging technique is an effective method to evaluate groundwater movement. Moving with the water, the isotope tracer distributes differently in different flow states. According to the depth and time distribution of radioactivity, flow state of the groundwater can be determined. In this paper, different flow states, i.e. laminar flow, turbulent flow and mixing flow, are analyzed, and calculation of the flow velocity is discussed. Also, we discuss how to distinguish the laminar flow part and turbulent part in a mixing flow. If one judges the flow state incorrectly, the error of flow velocity will be huge, hence the importance of flow state analysis. Finally, some problems in the practical projects and measuring methods are concluded. (authors)

  7. The development of iodine-123-labeled-methyl-branched fatty acids for myocardial SPECT imaging

    International Nuclear Information System (INIS)

    Knapp, F.F. Jr.; Kropp, J.

    1994-01-01

    Iodine-123-labeled fatty acids represent unique metabolic probes for correlation of energy substrate metabolism with regional myocardial viability. Interest in the use of these agents results from differences which are often observed in various types of heart disease between regional myocardial fatty acid uptake patterns and flow tracer distribution. Although the physiological basis is not completely understood, differences between regional fatty acid and flow tracer distribution may reflect alterations in important parameters of metabolism which can be useful for patient management or therapeutic strategy decision making. The iodine-123-labeled 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) fatty acid analogue was developed at the Oak Ridge National Laboratory and was recently introduced as ''Cardiodine trademark'' in 1993 by Nihon Medi-Physics for commercial distribution in Japan. Iodine-123-BMPP is also being used in clinical studies on an institutional approval basis at several institutions in Europe and the US. This paper describes the development of the concept of fatty acid ''metabolic trapping'' of methyl-branched fatty acids and their use for single photon emission computerized tomographic cardiac imaging

  8. Relationship between segmental thallium-201 uptake and regional myocardial blood flow in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Nichols, A.B.; Weiss, M.B.; Sciacca, R.R.; Cannon, P.J.; Blood, D.K.

    1983-01-01

    The relationship between the spatial distribution of thallium-201 in myocardial perfusion scintigrams and the distribution of left ventricular regional myocardial blood flow was examined in 25 patients undergoing coronary arteriography. Thallium-201 myocardial scintigrams were obtained after symptom-limited exercise and after a 4 hr delay. Regional myocardial blood flow was measured by the xenon-133 clearance method in patients at rest and during rapid atrial pacing to a double product comparable with that achieved during exercise stress testing. Patterns of regional thallium-201 activity and regional myocardial blood flow, recorded in similar left anterior oblique projections, were compared for left ventricular segments supplied by the left anterior descending (LAD) and left circumflex (CIRC) arteries. In 11 patients without significant lesions of the left coronary artery (group 1), thallium-201 was homogeneously distributed in the LAD and CIRC distributions in scintigrams taken during peak exercise; these scintigrams correspond to homogeneous regional myocardial blood flow in the LAD and CIRC regions during pacing-induced stress. In 14 patients with significant lesions of the left coronary artery (group 2), ratios of regional thallium-201 activity in the LAD and CIRC distributions of exercise scintigrams correlated well (r . .84) with ratios of regional myocardial blood flow measured during rapid pacing. Background subtraction altered the relationship between relative thallium-201 uptake and regional myocardial blood flow, causing overestimation of the magnitude of flow reduction on exercise scintigrams

  9. Clinical evaluation of sup 123 I-BMIPP myocardial scintigraphy in patients with hypertrophic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsuki, Katsuichi; Sugihara, Hiroki; Umamoto, Ikuo (Kyoto Prefectural Univ. of Medicine (Japan)) (and others)

    1992-02-01

    {sup 123}I-{beta}-methyl-p-iodophenylpentadecanoic acid ({sup 123}I-BMIPP) myocardial scintigraphy was performed in 13 patients with hypertrophic cardiomyopathy and compared with {sup 201}Tl myocardial scintigraphy performed within 3 months for evaluating the clinical significance of {sup 123}I-BMIPP myocardial scintigraphy. SPECT images were divided into 13 segments and segmental images were visually scored on a 4 (increased tracer uptake) to 0 (severely decreased tracer uptake) scale according to the tracer uptake. In comparison of {sup 123}I-BMIPP early images and {sup 201}Tl perfusion images, mismatches were seen in about 70% of all segments. The number of segments demonstrating lower myocardial uptake of {sup 123}I-BMIPP was larger than that of {sup 201}Tl. In hypertrophic regions, the tracer uptake of {sup 123}I-BMIPP early images was significantly lower than that of {sup 201}Tl images and the lower uptake of {sup 123}I-BMIPP delayed images was more marked. In non-hypertrophic regions, no significant difference was seen between the tracer uptakes of {sup 123}I-BMIPP early images and {sup 201}Tl images but the tracer uptake of {sup 123}I-BMIPP delayed images was significantly lower than that of {sup 201}Tl images. The mismatch between the tracer uptakes of {sup 123}I-BMIPP images and {sup 201}Tl images was thought to be a reflection of disordered myocardial fatty acid metabolism. 'Washout', the difference between the tracer uptakes of {sup 123}I-BMIPP early images and delayed images was also thought to be a reflection of disordered myocardial fatty acid metabolism. These results suggest that {sup 123}I-BMIPP is a promising radiopharmaceutical for evaluating disordered myocardial fatty acid metabolism in patients with HCM. (author).

  10. Technetium and rhenium complexes with modified fatty acid ligands 4. Evaluation of two new classes of {sup 99m}Tc-labelled fatty acids as potential tracers for myocardial metabolism imaging

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, A.; Kropp, J.; Deussen, A. [TU Dresden, Medizinische Fakultaet Carl Gustav Carus (Germany); Jung, C.M.; Spies, H.

    2002-01-01

    {sup 99m}Tc-labelled fatty acids were synthesized according to the '3+1' mixed-ligand approach and investigated as potential tracers for myocardial SPECT diagnostics on the model of the isolated guinea pig heart. The results indicate a low but specific myocardial uptake of the {sup 99m}Tc fatty acid derivatives subject to chain length and structure. (orig.)

  11. Elevated admission microalbuminuria predicts poor myocardial blood flow and 6-month mortality in ST-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention.

    Science.gov (United States)

    Chen, Jia Wei; Wang, Yong Liang; Li, Hong Wei

    2012-04-01

    Microalbuminuria (MA) is considered a major risk factor predisposing to cardiovascular morbidity and mortality. Outcomes after percutaneous coronary intervention (PCI) for patients with acute myocardial infarction (AMI) complicated by MA have been well described. However, data regarding admission MA and coronary and myocardial flow are scant. The aims of this study were to evaluate the effects of admission MA on coronary blood flow and prognosis in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary PCI. Did elevated admission microalbuminuria predict poor myocardial blood flow and 6-month mortality in ST-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention? A total of 247 patients undergoing primary PCI for STEMI within 12 hours after symptom onset were studied. Patients were divided into 2 groups according to admission urinary albumin extraction rate (UAER): (1) an MA group (UAER 20-200 µg/min), and (2) a normoalbuminuria (NA) group (UAER < 20 µg/min). Microalbuminuria was observed in 108 patients. Univariate analyses showed statistical differences between the NA and MA groups in serum creatine level, plasma glucose level, and peak creatine kinase level on presentation. Thrombolysis In Myocardial Infarction (TIMI) flow grades (TFGs) 0-2 in the MA group were more frequent (9.4% vs 21.2%, P < 0.05) than in the NA group, and corrected TIMI frame count was higher (23.9 ± 18.5 vs 29.8 ± 23.5, P < 0.05). Admission MA was an independent predictor of poor myocardial perfusion (adjusted relative risk: 3.14, 95% confidence interval: 0.99-6.78) and a higher rate of 6-month mortality in STEMI patients undergoing primary PCI (adjusted relative risk: 1.58, 95% confidence interval: 0.74-3.39). Admission MA levels are associated with impaired myocardial flow and poor prognosis in STEMI patients undergoing primary PCI. © 2012 Wiley Periodicals, Inc.

  12. Interpretation of field experiments on the flow of water and tracers through crystalline rock

    International Nuclear Information System (INIS)

    Hodgkinson, D.P.; Lever, D.A.; Robinson, P.C.; Bourke, P.J.

    1983-01-01

    This paper reviews recent work at Harwell on the interpretation of field experiments on the flow of water and tracers through crystalline rock. First a model for the radial transport of tracers through an isolated fracture is outlined and used to analyse a recent Swedish experiment at Finnsjoen. Secondly, the theoretical and experimental approach that is being used to quantify flow and dispersion through networks of fractures is described

  13. Relationship of myocardial hibernation, scar, and angiographic collateral flow in ischemic cardiomyopathy with coronary chronic total occlusion.

    Science.gov (United States)

    Wang, Li; Lu, Min-Jie; Feng, Lei; Wang, Juan; Fang, Wei; He, Zuo-Xiang; Dou, Ke-Fei; Zhao, Shi-Hua; Yang, Min-Fu

    2018-03-07

    The relationship between myocardial viability and angiographic collateral flow is not fully elucidated in ischemic cardiomyopathy (ICM) with coronary artery chronic total occlusion (CTO). We aimed to clarify the relationship between myocardial hibernation, myocardial scar, and angiographic collateral flow in these patients. Seventy-one consecutive ICM patients with 122 CTOs and 652 dysfunctional segments within CTO territories were retrospectively analyzed. Myocardial hibernation (perfusion-metabolism mismatch) and the extent of 18 F-fluorodeoxyglucose (FDG) abnormalities were assessed using 99m Tc-sestamibi and 18 F-FDG imaging. Myocardial scar was evaluated by late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging. Collateral flow observed on coronary angiography was assessed using Rentrop classification. In these patients, neither the extent nor frequency of myocardial hibernation or scar was related to the status of collateral flow. Moreover, the matching rate in determining myocardial viability was poor between any 2 imaging indices. The extent of 18 F-FDG abnormalities was linearly related to the extent of LGE rather than myocardial hibernation. Of note, nearly one-third (30.4%) of segments with transmural scar still had hibernating tissue. Hibernation and non-transmural scar had higher sensitivity (63.0% and 66.7%) than collateral flow (37.0%) in predicting global functional improvement. Angiographic collateral cannot accurately predict myocardial viability, and has lower sensitivity in prediction of functional improvement in CTO territories in ICM patients. Hence, assessment of myocardial viability with non-invasive imaging modalities is of importance. Moreover, due to the lack of correlation between myocardial hibernation and scar, these two indices are complementary but not interchangeable.

  14. Changes in myocardial blood flow and S-T segment elevation following coronary artery occlusion in dogs

    International Nuclear Information System (INIS)

    Smith, H.J.; Singh, B.N.; Norris, R.M.; John, M.B.; Hurley, P.J.

    1975-01-01

    The relationship between regional blood flow and epicardial S-T segment elevation was studied in 26 open-chest anesthetized dogs with left anterior coronary artery ligations. Changes in myocardial blood flow, measured with 15 +- 5 μ (diameter) microspheres labeled with 141 Ce, 85 Sr, and 169 Yb, were correlated with summated S-T segment elevations 15 minutes, 1 hour, and 2 hours after coronary artery occlusion. In normal areas, myocardial blood flow was 113 +- 5 ml/min 100 g -1 and summated S-T segment elevation was 0.3 +- 0.2 mv. Fifteen minutes after coronary artery occlusion in 26 dogs, S-T segment elevation was 5.7 +- 0.7 mv over the center of the infarct and myocardial blood flow was 10 +- 1 ml/min 100 g -1 ; over the border zone, myocardial blood flow was 63 +- 4 ml/min 100 g -1 and S-T segment elevation was 3.1 +- 0.1 mv. One third of the areas with a myocardial blood flow of 10 ml/min 100 g -1 or less had no S-T segment elevation. In the center and border zones of the infarct in 9 dogs, myocardial blood flow increased from 11 +- 2 and 67 +- 8 ml/min 100 g -1 15 minutes after occlusion to 20 +- 4 and 84 +- 12 ml/min 100 g -1 , respectively, 2 hours after coronary artery occlusion. These increases were not associated with a significant reduction in summated S-T segment elevation. The results do not suggest a simple quantitative relationship between epicardial S-T segment elevation and myocardial blood flow following acute coronary artery occlusion

  15. Endoscopic retrograde cholangiopancreatography causes reduced myocardial blood flow

    DEFF Research Database (Denmark)

    Christensen, M; Hendel, H W; Rasmussen, V

    2002-01-01

    BACKGROUND AND STUDY AIMS: Previous studies have shown that up to 50% of healthy patients may develop ST-segment changes during upper gastrointestinal endoscopy. The aim of the study was to evaluate myocardial blood flow in patients during endoscopic retrograde cholangiopancreatography (ERCP...

  16. Serial Myocardial Imaging after a Single Dose of Thallium-201

    Directory of Open Access Journals (Sweden)

    Takahiko Kamata

    2014-10-01

    Full Text Available Although thallium-201 exercise scintigraphy has been established for the detection of myocardial ischemia and viability, little is known regarding the myocardial thallium-201 kinetics during angioplasty. Herein, we report a 77-year old man with angina pectoris, in whom serial myocardial imaging after a single dose of thallium-201 was helpful in identifying not only the culprit lesion and myocardial viability, but also the dynamic changes in myocardial perfusion during angioplasty. Thallium-201 images after exercise showed a perfusion defect in the inferior wall, with a trivial redistribution 3 hours after the exercise and a marked improvement 24 hours later. Coronary angiography, performed 27 hours after exercise scintigraphy, showed severe stenosis in the right coronary artery. Guidewire crossing of the lesion interrupted the antegrade flow, which was restored after balloon dilation and stent implantation. Thallium-201 images, 2 hours after angioplasty (i.e., 30 hours after exercise, showed a decreased tracer uptake in the inferior wall, which improved the next day (i.e., 48 hours after exercise. Cardiac biomarkers were negative in the clinical course.

  17. Suitability of tracers

    International Nuclear Information System (INIS)

    Klotz, D.

    1999-01-01

    Hydrological tracer techniques are a means of making statements on the direction and speed of underground water. One of the simpler tasks is to find out whether there is hydrological communication between two given points. This requires a determination of the direction of flow, which places less exacting demands on the properties of the tracer than does the task of determining the flow velocity of underground water. Tracer methods can serve to infer from flow velocity the distance (flow) velocity, which is defined as the ratio between the distance between two points located in flow direction and the actual time it takes water to flow from one to the other [de

  18. Cardiac metabolism of 15 (p-I-123 phenyl-) pentadecanoic acid after intracoronary tracer application

    Energy Technology Data Exchange (ETDEWEB)

    Reske, S.N.; Reichmann, K.; Knopp, R.; Winkler, C.; Koischwitz, D.; Machulla, H.J.; Simon, H.

    1984-05-01

    Myocardial turnover of ..omega..-(p/sup 123/I-Phenyl-) pentadecanoic acid and release of its metabolites into the coronary sinus and peripheral blood has been studied in patients with coronary artery and valvular heart disease. After intracoronary tracer injection myocardial extraction fractions of 45-53% in control subjects were observed. In patients with coronary artery disease (CAD) normal to reduced values (34-61%) were established. Hydrophilic catabolites of I-PPA, probably p/sup 123/I-benzoic and -hippuric acid as well as small amounts of the non-metabolized tracer were found in coronary sinus and peripheral blood. Myocardial tracer uptake and clearance patterns were clearly different in normal myocardium when compared to that obtained in patients with CAD. Thus, evaluation of myocardial I-PPA metabolism might provide a new diagnostic tool for assessment of integrity of the heart's muscular metabolic function.

  19. Accuracy of tracer stimulus response experiments in laminar flows

    Czech Academy of Sciences Publication Activity Database

    Chlup, Hynek; Novotný, Pavel; Žitný, R.

    2012-01-01

    Roč. 55, 23-24 (2012), s. 6458-6462 ISSN 0017-9310 Institutional research plan: CEZ:AV0Z20760514 Keywords : residence time distribution * tracer injection * laminar convective dominated flow Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 2.315, year: 2012 http://www.sciencedirect.com/science/article/pii/S001793101200470X

  20. PET and SPET tracers for mapping the cardiac nervous system

    International Nuclear Information System (INIS)

    Langer, Oliver; Halldin, Christer

    2002-01-01

    The human cardiac nervous system consists of a sympathetic and a parasympathetic branch with (-)-norepinephrine and acetylcholine as the respective endogenous neurotransmitters. Dysfunction of the cardiac nervous system is implicated in various types of cardiac disease, such as heart failure, myocardial infarction and diabetic autonomic neuropathy. In vivo assessment of the distribution and function of cardiac sympathetic and parasympathetic neurones with positron emission tomography (PET) and single-photon emission tomography (SPET) can be achieved by means of a number of carbon-11-, fluorine-18-, bromine-76- and iodine-123-labelled tracer molecules. Available tracers for mapping sympathetic neurones can be divided into radiolabelled catecholamines, such as 6-[ 18 F]fluorodopamine, (-)-6-[ 18 F]fluoronorepinephrine and (-)-[ 11 C]epinephrine, and radiolabelled catecholamine analogues, such as [ 123 I]meta-iodobenzylguanidine, [ 11 C]meta-hydroxyephedrine, [ 18 F]fluorometaraminol, [ 11 C]phenylephrine and meta-[ 76 Br]bromobenzylguanidine. Resistance to metabolism by monoamine oxidase and catechol-O-methyl transferase simplifies the myocardial kinetics of the second group. Both groups of compounds are excellent agents for an overall assessment of sympathetic innervation. Biomathematical modelling of tracer kinetics is complicated by the complexity of the steps governing neuronal uptake, retention and release of these agents as well as by their high neuronal affinity, which leads to partial flow dependence of uptake. Mapping of cardiac parasympathetic neurones is limited by a low density and focal distribution pattern of these neurones in myocardium. Available tracers are derivatives of vesamicol, a molecule that binds to a receptor associated with the vesicular acetylcholine transporter. Compounds like (-)-[ 18 F]fluoroethoxybenzovesamicol display a high degree of non-specific binding in myocardium which restricts their utility for cardiac neuronal imaging. (orig.)

  1. Flow visualization in superfluid helium-4 using He2 molecular tracers

    Science.gov (United States)

    Guo, Wei

    Flow visualization in superfluid helium is challenging, yet crucial for attaining a detailed understanding of quantum turbulence. Two problems have impeded progress: finding and introducing suitable tracers that are small yet visible; and unambiguous interpretation of the tracer motion. We show that metastable He2 triplet molecules are outstanding tracers compared with other particles used in helium. These molecular tracers have small size and relatively simple behavior in superfluid helium: they follow the normal fluid motion at above 1 K and will bind to quantized vortex lines below about 0.6 K. A laser-induced fluorescence technique has been developed for imaging the He2 tracers. We will present our recent experimental work on studying the normal-fluid motion by tracking thin lines of He2 tracers created via femtosecond laser-field ionization in helium. We will also discuss a newly launched experiment on visualizing vortex lines in a magnetically levitated superfluid helium drop by imaging the He2 tracers trapped on the vortex cores. This experiment will enable unprecedented insight into the behavior of a rotating superfluid drop and will untangle several key issues in quantum turbulence research. We acknowledge the support from the National Science Foundation under Grant No. DMR-1507386 and the US Department of Energy under Grant No. DE-FG02 96ER40952.

  2. Bromide as chemical tracer to measure the liquid effluent flow at IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    Silva, Douglas B.; Faustino, Mainara G.; Monteiro, Lucilena R.; Cotrim, Marycel E.B.; Pires, Maria Aparecida F.

    2013-01-01

    Due to recent changes in CONAMA Resolution 357, which occurred through the publication of Resolution 430, on May 13, 2011 that now set standards about the effluent release, IPEN-CNEN/SP initiated several actions to improve the Environmental Monitoring Program (PMA-Q) of stable chemical compounds. Besides various parameters (physical and chemical) established by CONAMA, the submission of an annual pollution inventory report became necessary. The liquid effluent flow measurement is required to implement this inventory. Thereby, this paper describes a study that uses bromide as a chemical tracer. This paper presents the results of 6 tracer releases in IPEN wastewater collection network between 2011 and 2012. Two tracer releases designs were performed: single pulse and continuous releases performed with 1 to 6 hours duration, done by using one single piston pump manufactured by DIONEX. After the release, one fraction of the effluent was collected every 15 minutes at IPEN effluent monitoring station. The tracer concentration in the effluent was analyzed by ion chromatography and flow was calculated considering the dilution in the system and pump flow set up for the release. The flow values were measured in 6 events were determined and evaluated as per Brazilian regulation requirements. Experimental designs to be implemented during 2013 monitoring were also discussed in this paper, contributing to legal compliance and to improve IPEN's Environmental Monitoring Program for stable chemical compounds (PMA-Q). (author)

  3. Multi-Scale Thermal Heat Tracer Tests for Characterizing Transport Processes and Flow Channelling in Fractured Media: Theory and Field Experiments

    Science.gov (United States)

    de La Bernardie, J.; Klepikova, M.; Bour, O.; Le Borgne, T.; Dentz, M.; Guihéneuf, N.; Gerard, M. F.; Lavenant, N.

    2017-12-01

    The characterization of flow and transport in fractured media is particularly challenging because hydraulic conductivity and transport properties are often strongly dependent on the geometric structure of the fracture surfaces. Here we show how thermal tracer tests may be an excellent complement to conservative solute tracer tests to infer fracture geometry and flow channeling. We performed a series of thermal tracer tests at different scales in a crystalline rock aquifer at the experimental site of Ploemeur (H+ observatory network). The first type of thermal tracer tests are push-pull tracer tests at different scales. The temporal and spatial scaling of heat recovery, measured from thermal breakthrough curves, shows a clear signature of flow channeling. In particular, the late time tailing of heat recovery under channeled flow is shown to diverge from the T(t) α t-1,5 behavior expected for the classical parallel plate model and follow the scaling T(t) α 1/t(logt)2 for a simple channel modeled as a tube. Flow channeling is also manifested on the spatial scaling of heat recovery as flow channeling affects the decay of the thermal breakthrough peak amplitude and the increase of the peak time with scale. The second type of thermal tracer tests are flow-through tracer tests where a pulse of hot water was injected in a fracture isolated by a double straddle packer while pumping at the same flow rate in another fracture at a distance of about 10 meters to create a dipole flow field. Comparison with a solute tracer test performed under the same conditions also present a clear signature of flow channeling. We derive analytical expressions for the retardation and decay of the thermal breakthrough peak amplitude for different fracture geometries and show that the observed differences between thermal and solute breakthrough can be explained only by channelized flow. These results suggest that heat transport is much more sensitive to fracture heterogeneity and flow

  4. The use of tracer techniques in the study of soil water flows and contaminant transport

    International Nuclear Information System (INIS)

    Reeves, A.D.; Beven, K.J.

    1990-04-01

    This report reviews the use of different types of tracers in the characterisation of soil water flows and the implications of tracer studies for modelling contaminant transport. The tracers considered are a number of different anions, stable isotopes, radioactive tracers, organic dyes, fluorocarbons, gases, solid particles and water temperature. The theoretical basis for modelling the results of tracer experiments in terms of the traditional convective-dispersion equation (CDE) is outlined. A number of alternative modelling strategies are reviewed: the mobile/immobile water extension of the CDE; the Jury Transfer Function Model (TFM); the Aggregated Mixing Zone (AMZ) model and Random Particle Tracking models. The first will form the basis of the Systeme Hydrologique Europeen (SHE) contaminant transport component. The Jury and AMZ models are both linear models and are consequently limited to applications in which the flows may be considered to be quasi-steady or repeatable. Random particle tracking models have the advantage of both flexibility and applicability to transient and spatially variable flow domains. A random particle model is being implemented on a transputer workstation at Lancaster and will be used to explore the effect of sub-grid scale complexities on effective grid-scale parameter values for distributed models such as SHE. (author)

  5. Journal: Efficient Hydrologic Tracer-Test Design for Tracer ...

    Science.gov (United States)

    Hydrological tracer testing is the most reliable diagnostic technique available for the determination of basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed to facilitate the design of tracer tests by root determination of the one-dimensional advection-dispersion equation (ADE) using a preset average tracer concentration which provides a theoretical basis for an estimate of necessary tracer mass. The method uses basic measured field parameters (e.g., discharge, distance, cross-sectional area) that are combined in functional relatipnships that descrive solute-transport processes related to flow velocity and time of travel. These initial estimates for time of travel and velocity are then applied to a hypothetical continuous stirred tank reactor (CSTR) as an analog for the hydrological-flow system to develop initial estimates for tracer concentration, tracer mass, and axial dispersion. Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to be necessary for descri

  6. How do preferential flow features connect? Combining tracers and excavation to examine hillslope flow pathways on Vancouver Island, British Columbia, Canada.

    Science.gov (United States)

    Anderson, A. E.; Weiler, M.

    2005-12-01

    Preferential flow is a complex process that influences water flow and solute transport in soils at different scales. Many studies have advanced our understanding about the physical structures of preferential pathways and their effects on water flow and solute transport at the column and plot scale. However, we still know very little about how preferential flow features connect over large distances and how they influence water flow and solute transport at the hillslope and catchment scale. Working in a forested watershed on northeast Vancouver Island in British Columbia, Canada, we conducted several artificial tracer experiments under natural and steady state flow conditions to investigate how water and solutes move through a hillslope section above a road cutbank. After these ``black-box'' tracer experiments we applied a blue food dye and excavated the hillslope to visualize the stained flow pathways. Under natural conditions two of the largest preferential features transmitted water at rates up to 30 liters/min. When a NaCl tracer was applied 12 m upslope of the road cutbank one soil pipe transmitted 97% of the recovered tracer during two large storms. When tracer was applied 30 m upslope of the road a more diffused response was observed. For the steady-state conditions we pumped water into trenches excavated at 12 m and 30 m above the road and then applied NaCl during constant outflow. Pumping water into the 12 m trench produced flow from only two preferential features, but a response in all preferential features was observed when water was pumped into the 30 m trench. The detailed excavations showed that the largest preferential feature was connected to the lower trench by large soil pipes at the interface of the organic and mineral soil horizons that were connected by flow through the organic soil. Other cross sections between 12 and 30 m upslope revealed concentrated flow through coarse mineral soil, diffused flow through mineral and organic soil, flow along

  7. A tracer liquid image velocimetry for multi-layer radial flow in bioreactors.

    Science.gov (United States)

    Gao, Yu-Bao; Liang, Jiu-Xing; Luo, Yu-Xi; Yan, Jia

    2015-02-13

    This paper presents a Tracer Liquid Image Velocimetry (TLIV) for multi-layer radial flow in bioreactors used for cells cultivation of tissue engineering. The goal of this approach is to use simple devices to get good measuring precision, specialized for the case in which the uniform level of fluid shear stress was required while fluid velocity varied smoothly. Compared to the widely used Particles Image Velocimetry (PIV), this method adopted a bit of liquid as tracer, without the need of laser source. Sub-pixel positioning algorithm was used to overcome the adverse effects of the tracer liquid deformation. In addition, a neighborhood smoothing algorithm was used to restrict the measurement perturbation caused by diffusion. Experiments were carried out in a parallel plates flow chamber. And mathematical models of the flow chamber and Computational Fluid Dynamics (CFD) simulation were separately employed to validate the measurement precision of TLIV. The mean relative error between the simulated and measured data can be less than 2%, while in similar validations using PIV, the error was around 8.8%. TLIV avoided the contradiction between the particles' visibility and following performance with tested fluid, which is difficult to overcome in PIV. And TLIV is easier to popularize for its simple experimental condition and low cost.

  8. Field studies of transport and dispersion of atmospheric tracers in nocturnal drainage flows

    Science.gov (United States)

    Paul H. Gudiksen; Gilbert J. Ferber; Malcolm M. Fowler; Wynn L. Eberhard; Michael A. Fosberg; William R. Knuth

    1984-01-01

    A series of tracer experiments were carried out as part of the Atmospheric Studies in Complex Terrain (ASCOT) program to evaluate pollutant transport and dispersion characteristics of nocturnal drainage flows within a valley in northern California. The results indicate that the degree of interaction of the drainage flows with the larger scale regional flows are...

  9. Nuclear Cardiology: Are We Using the Right Protocols and Tracers the Right Way?

    Science.gov (United States)

    Dondi, Maurizio; Pascual, Thomas; Paez, Diana; Einstein, Andrew J

    2017-12-01

    The field of nuclear cardiology has changed considerably over recent years, with greater attention paid to safety and radiation protection issues. The wider usage of technetium-99m (Tc-99m)-labeled radiopharmaceuticals for single-photon emission computed tomography (SPECT) imaging using gamma cameras has contributed to better quality studies and lower radiation exposure to patients. Increased availability of tracers and scanners for positron emission tomography (PET) will help further improve the quality of studies and quantify myocardial blood flow and myocardial flow reserve, thus enhancing the contribution of non-invasive imaging to the management of coronary artery disease. The introduction of new instrumentation such as solid state cameras and new software will help reduce further radiation exposure to patients undergoing nuclear cardiology studies. Results from recent studies, focused on assessing the relationship between best practices and radiation risk, provide useful insights on simple measures to improve the safety of nuclear cardiology studies without compromising the quality of results.

  10. Relationship between myocardial flow reserve by oxygen-15 water positron emission tomography in the subacute phase of myocardial infarction and left ventricular remodeling in the chronic phase

    International Nuclear Information System (INIS)

    Ohara, Minako; Yukiiri, Kazushi; Masugata, Hisashi

    2008-01-01

    The purposes of this study were to examine the effects of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) on myocardial flow reserve in patients with acute myocardial infarction (AMI) in the subacute phase using oxygen-15 positron emission tomography (PET) and to elucidate the relationship between the myocardial flow reserve and remodeling in the chronic phase. Sixty patients who had been treated with coronary angioplasty within 12 h after the onset of AMI were enrolled. Patients were divided into an enalapril (ACEI) group and a candesartan (ARB) group. The myocardial flow reserve was measured by oxygen-15 water PET in the subacute phase from the 20th to the 30th day after the onset of AMI. Left ventriculography was performed to measure the left ventricular ejection fraction in the chronic phase about 6 months after the onset. Ten patients (33%) in the enalapril group and 4 patients (13%) in the candesartan group stopped taking their respective medications within a few days of starting, because of side effects such as cough or hypotension. Thus, the prevalence of medication intolerance was higher in the enalapril group. The myocardial flow reserve in the subacute phase and the left ventricular ejection fraction in the chronic phase were lower in the enalapril group (2.08±0.30 and 42±6%) than in the candesartan group (2.25±0.20 and 49±5%) (p<0.05). The myocardial flow reserve significantly correlated with the left ventricular ejection fraction in all patients (r=0.45, p<0.01). The myocardial flow reserve assessed by PET in the subacute phase after AMI was found to be related to left ventricular remodeling in the chronic phase. (author)

  11. The use of vitamins as tracer dyes for laser-induced fluorescence in liquid flow applications

    Science.gov (United States)

    Zähringer, Katharina

    2014-04-01

    Tracers commonly used in experimental flow studies are mostly nocuous to the environment and human health. Particularly, in large flow installations, this can become a problem. In this study, a solution of this problem is presented, based on using water-soluble vitamins. Five of them are examined here for their applicability in flow studies. Vitamins B2 and B6 turned out to be the most promising candidates, and the dependency of their fluorescence intensity on parameters like concentration, laser energy, temperature, and pH are determined for two commonly used laser excitation wavelengths (532, 355 nm). Two examples of application in a static mixer and a spray flow are shown and demonstrate the applicability of the vitamin tracers.

  12. Quantifying biologically and physically induced flow and tracer dynamics in permeable sediments

    Directory of Open Access Journals (Sweden)

    F. J. R. Meysman

    2007-08-01

    Full Text Available Insight in the biogeochemistry and ecology of sandy sediments crucially depends on a quantitative description of pore water flow and the associated transport of various solutes and particles. We show that widely different problems can be modelled by the same flow and tracer equations. The principal difference between model applications concerns the geometry of the sediment-water interface and the pressure conditions that are specified along this boundary. We illustrate this commonality with four different case studies. These include biologically and physically induced pore water flows, as well as simplified laboratory set-ups versus more complex field-like conditions: [1] lugworm bio-irrigation in laboratory set-up, [2] interaction of bio-irrigation and groundwater seepage on a tidal flat, [3] pore water flow induced by rotational stirring in benthic chambers, and [4] pore water flow induced by unidirectional flow over a ripple sequence. The same two example simulations are performed in all four cases: (a the time-dependent spreading of an inert tracer in the pore water, and (b the computation of the steady-state distribution of oxygen in the sediment. Overall, our model comparison indicates that model development for sandy sediments is promising, but within an early stage. Clear challenges remain in terms of model development, model validation, and model implementation.

  13. Near-kHz 3D tracer-based LIF imaging of a co-flow jet using toluene

    International Nuclear Information System (INIS)

    Miller, V A; Troutman, V A; Hanson, R K

    2014-01-01

    This work demonstrates tracer-based, high-repetition-rate planar (15 kHz) and three-dimensional (940 Hz) laser-induced fluorescence imaging. An off-the-shelf, pulsed, frequency-quadrupled Nd:YAG laser at 266 nm is used as the excitation light source, and a high-frame-rate intensified relay optic with a slow P46 phosphor coupled to a CMOS camera is used to image the fluorescence. Four different tracers are investigated (3-pentanone, acetone, anisole, and toluene) and relative signal levels are measured in the potential core of a laminar co-flow jet. Resulting SNR values range from 6 to 44 for the different tracers, and relative signal levels and SNR for each tracer are provided as an engineering-basis for tracer-based imaging diagnostic design. It was found that signal levels from anisole (relative to toluene) are about ten times less than suggested by other literature, owing to uncertainty in the reported absorption cross sections. Using toluene as a tracer and a custom-made piezo-actuated steering optic to scan the laser sheet, 3D LIF imaging at 940 Hz is demonstrated by visualizing a co-flow jet mixing with ambient air. (paper)

  14. Experimental studies of the physiologic properties of technetium-99m agents: Myocardial transport of perfusion imaging agents

    International Nuclear Information System (INIS)

    Meerdink, D.J.; Leppo, J.A.

    1990-01-01

    The physiologic properties of new technetium-99m-labeled myocardial imaging agents (Tc-99m sestamibi, an isonitrile; and Tc-99m teboroxime, a boronic acid adduct of technetium dioxime) are discussed and compared to thallium-201 (Tl-201). Studies with isolated hearts, subcellular fractions and cell cultures indicate that Tc-99m sestamibi, Tc-99m teboroxime and Tl-201 do not share common transport or sequestration mechanisms. Although peak Tc-99m sestamibi myocardial extraction over time is about half that of Tl-201 at equivalent coronary blood flows, the amount of Tc-99m sestamibi that remains in the heart is similar to that of Tl-201 because of its higher retention efficiency. The high retention efficiency for Tc-99m sestamibi also results in minimal redistribution. In contrast, Tc-99m teboroxime myocardial extraction is higher than that of Tl-201, but its retention is less efficient, resulting in relatively rapid washout characteristics which may quickly result in tracer redistribution. During reperfusion after a no-flow period, Tc-99m sestamibi extraction and retention increase, but for Tc-99m teboroxime and Tl-201 these values tend to decrease. All tracers show adequate transport characteristics for perfusion imaging, and differences in transport and retention should lead to the development of new clinical protocols.27 references

  15. Anatomy and function relation in the coronary tree: from bifurcations to myocardial flow and mass.

    Science.gov (United States)

    Kassab, Ghassan S; Finet, Gerard

    2015-01-01

    The study of the structure-function relation of coronary bifurcations is necessary not only to understand the design of the vasculature but also to use this understanding to restore structure and hence function. The objective of this review is to provide quantitative relations between bifurcation anatomy or geometry, flow distribution in the bifurcation and degree of perfused myocardial mass in order to establish practical rules to guide optimal treatment of bifurcations including side branches (SB). We use the scaling law between flow and diameter, conservation of mass and the scaling law between myocardial mass and diameter to provide geometric relations between the segment diameters of a bifurcation, flow fraction distribution in the SB, and the percentage of myocardial mass perfused by the SB. We demonstrate that the assessment of the functional significance of an SB for intervention should not only be based on the diameter of the SB but also on the diameter of the mother vessel as well as the diameter of the proximal main artery, as these dictate the flow fraction distribution and perfused myocardial mass, respectively. The geometric and flow rules for a bifurcation are extended to a trifurcation to ensure optimal therapy scaling rules for any branching pattern.

  16. Joint interpretation of two tracer tests with reversed flow fields

    International Nuclear Information System (INIS)

    Kunstmann, H.; Kinzelbach, W.; Marschall, P.; Li, G.

    1995-01-01

    Two dipole tracer experiments were performed in a fractured rock at the Grimsel Test Site in February/March 1993. In both experiments NaCl was used as a tracer. The extraction rate was twice the injection rate. In the second experiment injection and extraction were interchanged (Reverse-Experiment). Long tailing was characteristic for the breakthrough curves in both experiments. The tests were interpreted using a single fracture flow model. Tracer transport is described by advection/dispersion along the fracture allowing for diffusion into an immobile matrix. The authors were able to interpret the breakthrough curves for both experiments by one unique set of parameters, describing transport and baseflow. Uniqueness could only be achieved when using the information of both experiments. The authors conclude that performing a Reverse-Experiment is an indispensable tool for parameter identification in dipole tracer tests. A sensitivity analysis suggested that not only matrix diffusion is responsible for the tailing in the breakthrough curves but also transversal dispersivity. Further, the typical exchange time between mobile and immobile media was too small to be attributed to matrix diffusion in the strict sense which will cause tailing even at large spatial and temporal scales. Analysis of the covariance matrices showed that the parameters have small errors but high correlation

  17. Effect of impaired fatty acid oxidation on myocardial kinetics of 11C- and 123I-labelled fatty acids

    International Nuclear Information System (INIS)

    Lerch, R.

    1986-01-01

    Positron emission tomography with palmitate 11 C and single photon imaging with terminally radioiodinated fatty acid analogues (FFA 123 I) were evaluated for the noninvasive assessment of regional myocardial fatty acid metabolism during ischaemia. Decreased uptake of tracer and delayed clearance of activity in the ischaemic myocardium were reported for both 11 C- and 123 I-labelled compounds. However, since during ischaemia both myocardial blood flow and oxidative metabolism are reduced concomitantly, either factor can be responsible for the changes observed. Experimental preparations in which fatty acid metabolism can be modified independently of flow are helpful for the characterization of the relationship between metabolism and myocardial kinetics of labelled fatty acids. Results obtained during flow-independent inhibition of fatty acid oxidation include the following observations: - In dogs with controlled coronary perfusion the rate of clearance of palmitate 11 C-activity is decreased during diminished delivery of oxygen, regardless of whether myocardial perfusion is concomitantly reduced or not. - In isolated rabbit hearts perfused at normal flow, the extraction of FFA 123 I is decreased during hypoxia. - During pharmacological inhibition of fatty acid oxidation the deiodination of FFA 123 I is markedly reduced in rat hearts in vivo and in vitro. (orig.)

  18. Numerical flow models and their calibration using tracer based ages: Chapter 10

    Science.gov (United States)

    Sanford, W.

    2013-01-01

    Any estimate of ‘age’ of a groundwater sample based on environmental tracers requires some form of geochemical model to interpret the tracer chemistry (chapter 3) and is, therefore, referred to in this chapter as a tracer model age. the tracer model age of a groundwater sample can be useful for obtaining information on the residence time and replenishment rate of an aquifer system, but that type of data is most useful when it can be incorporated with all other information that is known about the groundwater system under study. groundwater fl ow models are constructed of aquifer systems because they are usually the best way of incorporating all of the known information about the system in the context of a mathematical framework that constrains the model to follow the known laws of physics and chemistry as they apply to groundwater flow and transport. It is important that the purpose or objective of the study be identified first before choosing the type and complexity of the model to be constructed, and to make sure such a model is necessary. The purpose of a modelling study is most often to characterize the system within a numerical framework, such that the hydrological responses of the system can be tested under potential stresses that might be imposed given future development scenarios. As this manual discusses dating as it applies to old groundwater, most readers are likely to be interested in studying regional groundwater flow systems and their water resource potential.

  19. Validation of {sup 99m}Tc-labeled '4+1' fatty acids for myocardial metabolism and flow imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mirtschink, Peter [Institute of Physiology, Technical University Dresden, 01307 Dresden (Germany)], E-mail: peter_mirtschink@web.de; Stehr, Sebastian N. [Department of Anesthesiology, Technical University Dresden, 01307 Dresden (Germany); Walther, Martin; Pietzsch, Jens; Bergmann, Ralf; Pietzsch, Hans-Juergen [Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, 01314 Dresden (Germany); Weichsel, Johannes; Pexa, Annette; Dieterich, Peter [Institute of Physiology, Technical University Dresden, 01307 Dresden (Germany); Wunderlich, Gerd [Department of Nuclear Medicine, Technical University Dresden, 01307 Dresden (Germany); Binas, Bert [Department of Veterinary Pathobiology, Texas A and M University, College Station, TX 77843 (United States); Kropp, Joachim [Department of Nuclear Medicine Carl-Thiem Hospital Cottbus, 03048 Cottbus (Germany); Deussen, Andreas [Institute of Physiology, Technical University Dresden, 01307 Dresden (Germany)

    2009-10-15

    Introduction: {sup 13}C, {sup 18}F and {sup 123}I fatty acids (FA) are used for myocardial imaging. Recently, our group showed that [{sup 99m}Tc]-labeled '4+1' FA are extracted into the rat and guinea pig myocardium. The present study evaluates determinants of myocardial uptake and whole body biodistribution of these FA derivatives. Methods: Studies were performed with isolated perfused hearts of Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) with a FAT/CD36 deficiency, as well as with heart type FA binding protein knockout mice (H-FABP){sup -/-} and H-FABP{sup +/+}. Eight 4+1-{sup 99m}Tc-FA were applied for 3 min followed by 1-min washout. A mathematical model was used to analyze FA dynamics and binding to proteins. Whole-body distribution was studied in rats with and without Tween 80. In vitro fractionation studies with [{sup 99m}Tc]-FA assessed red blood cell uptake as well as association with plasma lipoproteins very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Results: Myocardial extraction was 19.0-33.0% of the infused dose in isolated WKY and 15.2-26.4% in SHR hearts. However, H-FABP{sup -/-} showed a marked reduction of tracer extraction [2.8{+-}0.6%ID (percent injected dose) vs. 17{+-}2%ID P<.001]. Uptake in red blood cells (<1.2%ID) and incorporation into lipoproteins were negligible. Incubation of {sup 99m}Tc-FA with albumin reduced ventricular extraction (P<.001) into the range of established iodinated FA tracers. polyoxyethylene(20) sorbitan monooleate improved the heart-to-liver ratio in the biodistribution studies. Conclusions: Myocardial uptake of [{sup 99m}Tc]-FA 4+1 derivatives is dependent on H-FABP. These substances may therefore provide a new tool to specifically assess regional myocardial changes of H-FABP.

  20. Scaling of Myocardial Mass to Flow and Morphometry of Coronary Arteries

    OpenAIRE

    Choy, Jenny Susana; Kassab, Ghassan S.

    2008-01-01

    There is no doubt that scaling relations exist between myocardial mass and morphometry of coronary vasculature. The purpose of this study is to quantify several morphological (diameter, length, and volume) and functional (flow) parameters of the coronary arterial tree in relation to myocardial mass. Eight normal porcine hearts of 117-244 g (mean of 177.5±32.7) were used in this study. Various coronary sub-trees of the Left Anterior Descending (LAD), Right Coronary (RCA) and Left Circumflex (L...

  1. Effect of loading-dose ticagrelor on coronary blood flow, left ventricular remodeling and myocardial enzyme spectrum in patients with acute myocardial infarction after interventional therapy

    Directory of Open Access Journals (Sweden)

    Xiao-Rui Xie

    2016-12-01

    Full Text Available Objective: To study the effect of loading-dose ticagrelor on coronary blood flow, left ventricular remodeling and myocardial enzyme spectrum in patients with acute myocardial infarction after interventional therapy. Methods: A total of 86 patients with acute myocardial infarction who received emergency PCI in our hospital between May 2013 and May 2016 were selected and randomly divided into two groups, ticagrelor group received perioperative ticagrelor therapy and clopidogrel group received perioperative clopidogrel therapy. After PCI, coronary blood flow reperfusion was evaluated, serum myocardial remodeling indexes and myocardial enzymes were determined, and cardiac color Doppler ultrasonography was conducted to determine the cardiac function indexes. Results: TIMI grading and TMPG grading of ticagrelor group after PCI were significantly higher than those of clopidogrel group; serum MMP9, BNP, CITP, PICP, PIIINP, CK, CK-MB, cTnI and cTnT content of ticagrelor group 24h after operation were significantly lower than those of clopidogrel group; LVEDD, LVSED and LVMI of ticagrelor group 2 weeks after operation were significantly lower than those of clopidogrel group while LVEF was significantly higher than that of clopidogrel group. Conclusion: Peri-PCI loading-dose ticagrelor can improve coronary blood perfusion and reduce ventricular remodeling and myocardial injury in patients with acute myocardial infarction.

  2. Radioiodinated BMIPP for myocardial imaging - current status and future perspectives

    International Nuclear Information System (INIS)

    Knapp, F.F. Jr.; Kropp, J.; Franken, P.R.

    1998-01-01

    Since the 1970's both basic research applications and clinical use of radioiodinated free fatty acids has continued to be of interest in nuclear cardiology. Clinical use of iodine-123-labeled fatty acids offers a unique opportunity for direct or indirect evaluation of alterations in myocardial metabolism by single photon computed tomography (SPECT). The relationship between the negative 'mismatches' often observed between regional fatty acid uptake and perfusion tracer distribution (i.e. BMIPP defect larger than flow tracer defect) has been an important observation which can often provide information on myocardial viability. Although the widespread use of the iodine-123-labeled 15-(p-iodophenyl)-3-(R, S)-methylpentadecanoic acid (BMIPP) analogue in Japan continues to provide extensive clinical data defining indications for the use of this agent, it remains to be seen, however, if iodine-123-labeled fatty acids such as BMIPP will enter routine clinical use in other countries, since their commercial availability as approved radiopharmaceuticals will be required. In this paper further studies describing the resolution and evaluation of the metabolism and myocardial uptake and release kinetics of the 3R- and 3S-BMIPP isomers are described. Although it is beyond the scope of this brief paper to review and discuss the voluminous data which have been published concerning both clincial applications and research studies with BMIPP over the last several years, the issues associated with the broader clinical use of BMIPP and other iodine-123-labeled fatty acid agents are discussed. (orig.) [de

  3. Scintigraphic anatomy of coronary artery disease in digital thallium-201 myocardial images

    International Nuclear Information System (INIS)

    Wainwright, R.J.

    1981-01-01

    One hundred and eight patients with single and multiple vessel coronary artery disease confirmed by arteriography were evaluated by exercise thallium-201 ( 201 Tl) myocardial scintigraphy to determine the scintigraphic appearances of specific coronary stenoses. In general proximal stenoses caused more widespread, but not necessarily more severe, myocardial tracer deficit, than distal stenoses. In particular, proximal dominant right coronary artery disease was specifically associated with extensive inferior wall tracer deficit in the anterior scintigram, whereas proximal left circumflex disease caused similar tracer depletion best visualised in the left lateral scintigram. A triad of uptake defects was caused by left anterior descending coronary artery disease; one of these defects called 'diagonal window tracer deficit' was the most useful scintigraphic sign distinguishing proximal from distal disease in the left anterior descending coronary artery. Certain scintigraphic patterns of 201 Tl myocardial accumulation appear invaluable in the noninvasive localisation of stenoses within specific coronary arteries and thus may be useful in predicting life-threatening coronary artery disease which should be confirmed by definitive coronary arteriography. The digital 201 Tl myocardial scintigram also provides an independent functional guide to the interpretation of coronary arteriograms and may be helpful in the planning of aortocoronary bypass graft surgery. (author)

  4. Reduction of myocardial blood flow reserve in idiopathic dilated cardiomyopathy without overt heart failure and its relation with functional indices: an echo-Doppler and positron emission tomography study.

    Science.gov (United States)

    Morales, Maria-Aurora; Neglia, Danilo; L'Abbate, Antonio

    2008-08-01

    Myocardial blood flow during pharmacological vasodilatation is depressed in patients with idiopathic dilated cardiomyopathy even the in absence of overt heart failure; the extent of myocardial blood flow abnormalities is not predictable by left ventricular ejection fraction (LVEF) and diastolic dimensions. To assess whether myocardial blood flow impairment in idiopathic dilated cardiomyopathy without overt heart failure can be related to Doppler-derived dP/dt and to echocardiographically determined left ventricular end systolic stress - which is linked to myocardial blood flow reserve in advanced disease. Twenty-six patients, New York Heart Association Class I-II, (LVEF 37.4 +/- 1.4%, left ventricular diastolic dimensions 62.6 +/- 0.9 mm) underwent resting/dipyridamole [13N]NH3 flow positron emission tomography and an ultrasonic study. Regional myocardial blood flow values (ml/min per g) were computed from positron emission tomography data in 13 left ventricular (LV) myocardial regions and averaged to provide mean myocardial blood flow and myocardial blood flow reserve, defined as dipyridamole/resting mean myocardial blood flow ratio. Resting myocardial blood flow was 0.686 +/- 0.045, dipyridamole myocardial blood flow 1.39 +/- 0.15 and myocardial blood flow reserve 2.12 +/- 0.2, lower than in controls (P < 0.01). The ratio dP/dt was directly related to dipyridamole myocardial blood flow and myocardial blood flow reserve (r = 0.552 and 0.703, P < 0.005 and P < 0.0001); no relation was found between myocardial blood flow and LVEF left ventricular diastolic dimensions, and left ventricular end systolic stress. In idiopathic dilated cardiomyopathy patients without overt heart failure, the extent of myocardial blood flow reserve impairment is related to dP/dt but not to more classical indices of left ventricular function.

  5. Quantifying sources of fine sediment supplied to post-fire debris flows using fallout radionuclide tracers

    Science.gov (United States)

    Smith, Hugh; Sheridan, Gary; Nyman, Petter; Child, David; Lane, Patrick; Hotchkis, Michael

    2013-04-01

    The supply of fine sediment and ash has been identified as an important factor contributing to the initiation of runoff-generated debris flows after fire. However, despite the significance of fines for post-fire debris flow generation, no investigations have sought to quantify sources of this material in debris flow affected catchments. In this study, we employ fallout radionuclides (Cs-137, excess Pb-210 and Pu-239,240) as tracers to measure proportional contributions of fine sediment (bank sources to levee and terminal fan deposits formed by post-fire debris flows in two forest catchments in southeastern Australia. While Cs-137 and excess Pb-210 have been widely used in sediment tracing studies, application of Pu as a tracer represents a recent development and was limited to only one catchment. The estimated range in hillslope surface contributions of fine sediment to individual debris flow deposits in each catchment was 22-69% and 32-74%, respectively. No systematic change in the source contributions to debris flow deposits was observed with distance downstream from channel initiation points. Instead, spatial variability in source contributions was largely influenced by the pattern of debris flow surges forming the deposits. Linking the sediment tracing with interpretation of depositional evidence allowed reconstruction of temporal sequences in sediment source contributions to debris flow surges. Hillslope source inputs dominated most elevated channel deposits such as marginal levees that were formed under peak flow conditions. This indicated the importance of hillslope runoff and sediment supply for debris flow generation in both catchments. In contrast, material stored within channels that was deposited during subsequent surges was predominantly channel-derived. The results demonstrate that fallout radionuclide tracers may provide unique information on the changing source contributions of fine sediment during debris flow events.

  6. Results of myocardial SPECT with fatty acids in coronary artery disease

    International Nuclear Information System (INIS)

    Reske, S.N.; Kropp, J.; Reichmann, K.; Winkler, C.; Knapp, F.F.; Nitsch, J.

    1986-01-01

    New developments in radiopharmacology of 123 I-labeled metabolic tracers and single-photon emission computerized tomography (SPECT) allow now-a-days the assessment of parameters of cardiac energy metabolism in well-defined areas of the heart muscle. This article will present a brief outline of the basic pathophysiological principles used in the application of 123 I-labeled phenyl fatty acids for the evaluation of CAD. First clinical results suggest an important application of cardiac fatty acid metabolic imaging to the detection, localisation and conceivable quantitation of myocardial ischemia, myocardial infarction and assessment of tissue viability. In addition to the diagnostic applications in CAD, cardiac fatty acid metabolic imaging may provide new perspectives to pathophysiological investigations of the coupling of local flow and substrate utilisation in vivo and the effect of therapeutic interventions. (orig.) [de

  7. Methodology for the determination of underground water velocity, direction and flow, by using radioactive tracers

    International Nuclear Information System (INIS)

    Aoki, P.E.

    1983-01-01

    A basic route determining velocity and direction of ground water flow by using radioactive tracers is presented. Emphasis has been given to hydrology and nuclear energy concepts, to the construction of some specific equipment, to the calibration of radiation detectors and to the practical applications in borehole. 82 Br and 51 Cr have been chosen as tracers for the Darcy's velocity and direction determinations, respectively. From the obtained value of Darcy's velocity, the laminar flow was confirmed according to the admitted hypothesis. Comparisons of the Darcy's velocity values and flow direction have been made with values obtained using pumping tests and survey of the equipotential curves, where it can be concluded that they are of the same largeness and then, from a practical view, approximate. (Author) [pt

  8. Influence of pre-infarction angina, collateral flow, and pre-procedural TIMI flow on myocardial salvage index by cardiac magnetic resonance in patients with ST-segment elevation myocardial infarction.

    Science.gov (United States)

    Lønborg, Jacob; Kelbæk, Henning; Vejlstrup, Niels; Bøtker, Hans Erik; Kim, Won Yong; Holmvang, Lene; Jørgensen, Erik; Helqvist, Steffen; Saunamäki, Kari; Thuesen, Leif; Krusell, Lars Romer; Clemmensen, Peter; Engstrøm, Thomas

    2012-05-01

    In patients with ST-segment elevation myocardial infarction (STEMI) pre-infarction angina, pre-procedural TIMI flow and collateral flow to the myocardium supplied by the infarct related artery are suggested to be cardioprotective. We evaluated the effect of these factors on myocardial salvage index (MSI) and infarct size adjusting for area at risk in patients with STEMI treated with primary percutaneous coronary intervention. Cardiac magnetic resonance (CMR) was used to measure myocardial area at risk within 1-7 days and final infarct size 90 ± 21 days after the STEMI in 200 patients. MSI was calculated as (area-at-risk infarct size) / area-at-risk. Patients with pre-infarction angina had a median MSI of 0.80 (IQR 0.67 to 0.86) versus 0.72 (0.61 to 0.80) in those without pre-infarction angina, P = 0.004). In a regression analysis of the infarct size plotted against the area-at-risk there was a strong trend that the line for the pre-infarction angina group was below the one for the non-angina group (P = 0.05). Patients with pre-procedural TIMI flow 0/1, 2 and 3 had a median MSI of (0.69 (IQR 0.59 to 0.76), 0.78 (0.68 to 0.86) and 0.85 (0.77 to 0.91), respectively (PCollateral flow did not change MSI (P = 0.45) nor area-at-risk (P = 0.40) and no significant difference in infarct size adjusted for area at risk (P = 0.25) was observed. Pre-infarction angina increases MSI in patients with STEMI supporting the theory that pre-infarction angina leads to ischemic preconditioning. As opposed to the presence of angiographically visible collateral flow to the infarct area pre-procedural TIMI flow is strongly associated with MSI.

  9. Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation

    International Nuclear Information System (INIS)

    Mays, A.E. Jr.; Cobb, F.R.

    1984-01-01

    This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured. Curvilinear regression analyses between thallium-201 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second- as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-201 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow

  10. Tracer research in process engineering

    International Nuclear Information System (INIS)

    Iller, E.

    1992-01-01

    The book is a review of modern applications of tracer techniques in chemical and process engineering studies. The next topics have been extensively presented: 1) media flow through apparatus; 2) the tracers in the study of media flow dynamics through apparatus; 3) mathematical interpretation of experimental data from impulse-response method; 4) the models of media flow through chemical reactors and apparatus; 5) radiotracers in mass transport study; 6) examples of practical applications of tracer methods in industrial objects. 84 refs, 96 figs, 31 tabs

  11. Utility of bromide and heat tracers for aquifer characterization affected by highly transient flow conditions

    Science.gov (United States)

    Ma, Rui; Zheng, Chunmiao; Zachara, John M.; Tonkin, Matthew

    2012-08-01

    A tracer test using both bromide and heat tracers conducted at the Integrated Field Research Challenge site in Hanford 300 Area (300A), Washington, provided an instrument for evaluating the utility of bromide and heat tracers for aquifer characterization. The bromide tracer data were critical to improving the calibration of the flow model complicated by the highly dynamic nature of the flow field. However, most bromide concentrations were obtained from fully screened observation wells, lacking depth-specific resolution for vertical characterization. On the other hand, depth-specific temperature data were relatively simple and inexpensive to acquire. However, temperature-driven fluid density effects influenced heat plume movement. Moreover, the temperature data contained "noise" caused by heating during fluid injection and sampling events. Using the hydraulic conductivity distribution obtained from the calibration of the bromide transport model, the temperature depth profiles and arrival times of temperature peaks simulated by the heat transport model were in reasonable agreement with observations. This suggested that heat can be used as a cost-effective proxy for solute tracers for calibration of the hydraulic conductivity distribution, especially in the vertical direction. However, a heat tracer test must be carefully designed and executed to minimize fluid density effects and sources of noise in temperature data. A sensitivity analysis also revealed that heat transport was most sensitive to hydraulic conductivity and porosity, less sensitive to thermal distribution factor, and least sensitive to thermal dispersion and heat conduction. This indicated that the hydraulic conductivity remains the primary calibration parameter for heat transport.

  12. The development of radioiodinated fatty acids for myocardial imaging

    International Nuclear Information System (INIS)

    Knapp, F.F. Jr.

    1993-01-01

    Since free fatty acids are the principal energy source for the normally oxygenated myocardium, the use of iodine-123-labeled fatty acid analogues is an attractive approach for myocardial imaging. Interest in the use of these substances results from divergent fatty acid metabolic pathways in ischemic (triglyceride storage) versus normoxic tissue (β-oxidative clearance), following flow-dependent delivery. Iodine-123-labeled fatty acids may offer a unique opportunity to identity myocardial viability using single photon emission tomography. The development of structurally-modified fatty acids became of interest because of the relatively long acquisition periods required for SPECT. The significant time required by early generation single- or dual-head SPECT systems for data acquisition requires minimal redistribution during the acquisition period to ensure accurate evaluation of the regional fatty acid distribution pattern after re-construction. Research has focussed on the evaluation of structural modifications which can be introduced into the fatty acid chain which would inhibit the subsequent β-oxidative catabolism which normally results in rapid myocardial clearance. Introduction of a methyl group in position-3 of the fatty acid carbon chain has been shown to significantly delay myocardial clearance and iodine-123-labeled 15-(p-iodophenyl)-3- R,S-methylpentadecanoic acid (BMIPP) is a new tracer based on this strategy

  13. Neuromodulation therapy does not influence blood flow distribution or left-ventricular dynamics during acute myocardial ischemia.

    Science.gov (United States)

    Kingma, J G; Linderoth, B; Ardell, J L; Armour, J A; DeJongste, M J; Foreman, R D

    2001-08-13

    Electrical stimulation of the dorsal aspect of the upper thoracic spinal cord is used increasingly to treat patients with angina pectoris refractory to conventional therapeutic strategies. The purpose of this study was to determine whether spinal cord stimulation (SCS) in dogs affects regional myocardial blood flow and left-ventricular (LV) function before and during transient obstruction of the left anterior descending coronary artery (LAD). In anesthetized dogs, regional myocardial blood flow distribution was determined using radiolabeled microspheres and left-ventricular function was measured by impedance-derived pressure-volume loops. SCS was accomplished by stimulating the dorsal T1-T2 segments of the spinal cord using epidural bipolar electrodes at 90% of motor threshold (MT) (50 Hz, 0.2-ms duration). Effects of 5-min SCS were assessed under basal conditions and during 4-min occlusion of the LAD. SCS alone evoked no change in regional myocardial blood flow or cardiovascular indices. Transient LAD occlusion significantly diminished blood flow within ischemic, but not in non-ischemic myocardial tissue. Left ventricular pressure-volume loops were shifted rightward during LAD occlusion. Cardiac indices were altered similarly during LAD occlusion and concurrent SCS. SCS does not influence the distribution of blood flow within the non-ischemic or ischemic myocardium. Nor does it modify LV pressure-volume dynamics in the anesthetized experimental preparation.

  14. Use of myocardial imaging in the evaluation of patients with cardiovascular disease

    Energy Technology Data Exchange (ETDEWEB)

    Pitt, B.; Strauss, H.W.; Trhall, J.H.

    1980-01-01

    The role of radioisotope tracer techniques in the evaluation of patients with congenital heart disease, valvular heart disease, suspected myocardial infarction, ischemia or suspected ventricular dysfunction is reviewed. Thallium-201 myocardial imaging and exercise blood pool imaging and Technetium-88m pyrophosphate imaging of myocardial infarction are most commonly used.

  15. Relationship Between Coronary Contrast-Flow Quantitative Flow Ratio and Myocardial Ischemia Assessed by SPECT MPI.

    Science.gov (United States)

    Smit, Jeff M; Koning, Gerhard; van Rosendael, Alexander R; Dibbets-Schneider, Petra; Mertens, Bart J; Jukema, J Wouter; Delgado, Victoria; Reiber, Johan H C; Bax, Jeroen J; Scholte, Arthur J

    2017-10-01

    A new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called "contrast-flow quantitative flow ratio (cQFR)". Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). Patients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal. Two hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters.

  16. PET measurements of myocardial blood flow post myocardial infarction: Relationship to invasive and cardiac magnetic resonance studies and potential clinical applications.

    Science.gov (United States)

    Gewirtz, Henry

    2017-12-01

    This review focuses on clinical studies concerning assessment of coronary microvascular and conduit vessel function primarily in the context of acute and sub acute myocardial infarction (MI). The ability of quantitative PET measurements of myocardial blood flow (MBF) to delineate underlying pathophysiology and assist in clinical decision making in this setting is discussed. Likewise, considered are physiological metrics fractional flow reserve, coronary flow reserve, index of microvascular resistance (FFR, CFR, IMR) obtained from invasive studies performed in the cardiac catheterization laboratory, typically at the time of PCI for MI. The role both of invasive studies and cardiac magnetic resonance (CMR) imaging in assessing microvascular function, a key determinant of prognosis, is reviewed. The interface between quantitative PET MBF measurements and underlying pathophysiology, as demonstrated both by invasive and CMR methodology, is discussed in the context of optimal interpretation of the quantitative PET MBF exam and its potential clinical applications.

  17. Mapping fracture flow paths with a nanoscale zero-valent iron tracer test and a flowmeter test

    Science.gov (United States)

    Chuang, Po-Yu; Chia, Yeeping; Chiu, Yung-Chia; Teng, Mao-Hua; Liou, Sofia Ya Hsuan

    2018-02-01

    The detection of preferential flow paths and the characterization of their hydraulic properties are important for the development of hydrogeological conceptual models in fractured-rock aquifers. In this study, nanoscale zero-valent iron (nZVI) particles were used as tracers to characterize fracture connectivity between two boreholes in fractured rock. A magnet array was installed vertically in the observation well to attract arriving nZVI particles and identify the location of the incoming tracer. Heat-pulse flowmeter tests were conducted to delineate the permeable fractures in the two wells for the design of the tracer test. The nZVI slurry was released in the screened injection well. The arrival of the slurry in the observation well was detected by an increase in electrical conductivity, while the depth of the connected fracture was identified by the distribution of nZVI particles attracted to the magnet array. The position where the maximum weight of attracted nZVI particles was observed coincides with the depth of a permeable fracture zone delineated by the heat-pulse flowmeter. In addition, a saline tracer test produced comparable results with the nZVI tracer test. Numerical simulation was performed using MODFLOW with MT3DMS to estimate the hydraulic properties of the connected fracture zones between the two wells. The study results indicate that the nZVI particle could be a promising tracer for the characterization of flow paths in fractured rock.

  18. Myocardial blood flow assessment with 82rubidium-PET imaging in patients with left bundle branch block

    International Nuclear Information System (INIS)

    Falcao, Andrea; Chalela, William; Giorgi, Maria Clementina; Imada, Rodrigo; Soares Junior, Jose; Do Val, Renata; Oliveira, Marco Antonio; Izaki, Marisa; Kalil Filho, Roberto; Meneghetti, Jose C.

    2015-01-01

    Objectives: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. Objective: we sought to investigate rubidium-82 ( 82 Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. Methods: thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress 82 Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal 82 Rb-positron emission tomography studies and without left bundle branch block (GII). Results: stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p>0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). Conclusion: the data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by 82 Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients

  19. Flow pathways in the Slapton Wood catchment using temperature as a tracer

    Science.gov (United States)

    Birkinshaw, Stephen J.; Webb, Bruce

    2010-03-01

    SummaryThis study investigates the potential of temperature as a tracer to provide insights into flow pathways. The approach couples fieldwork and modelling experiments for the Eastergrounds Hollow within the Slapton Wood catchment, South Devon, UK. Measurements in the Eastergrounds Hollow were carried out for soil temperature, spring temperature, and the stream temperature and use was made of an existing 1989-1991 data set for the entire Slapton Wood catchment. The predominant flow in this hollow is a result of subsurface stormflow, and previous work has suggested that the water flows vertically down through the soil and then subsurface stormflow occurs at the soil/bedrock interface where the water is deflected laterally. The depth of the subsurface stormflow was previously thought to be around 2.2 m. However, analysis of the new spring, stream and soil temperature data suggests a deeper pathway for the subsurface stormflow. Modelling of water flow and heat transport was carried out using SHETRAN and this was calibrated to reproduce the water flow in the entire Slapton Wood catchment and soil temperatures in the Eastergrounds Hollow. The model was tested for the entire Eastergrounds Hollow with two different soil depths. A depth of 2.2 m, based on previous knowledge, was unable to reproduce the Eastergrounds spring temperature. A depth of 3.7 m produced an excellent comparison between measured and simulated stream and spring temperatures in the Eastergrounds Hollow. This work suggests that the depth of the flow pathways that produce the subsurface stormflow are deeper than previously thought. It also provides a demonstration on the use of temperature as a tracer to understand flow pathways.

  20. Using Dye Tracer for Visualization of Preferential Flow at Macro- and Microscales

    Czech Academy of Sciences Publication Activity Database

    Kodešová, R.; Němeček, K.; Kodeš, V.; Žigová, Anna

    2012-01-01

    Roč. 11, č. 1 (2012), s. 287-295 ISSN 1539-1663 R&D Projects: GA ČR GA526/08/0434 Institutional research plan: CEZ:AV0Z30130516 Keywords : dye tracer * preferential flow * soil types * macro- and microsccale Subject RIV: DF - Soil Science Impact factor: 2.200, year: 2012

  1. Myocardial blood flow during induced aortic hypertension in dogs

    International Nuclear Information System (INIS)

    Thai, B.N.; Levesque, M.J.; Nerem, R.M.

    1986-01-01

    Myocardial blood flow was measured in anesthetized dogs during control conditions and under conditions where the aortic pressure was increased due to aortic constriction or during infusion. Blood flow was measured using the radioactive microsphere technique. Radioactive microspheres (15 m Ce-141, Sr-85, and Sc-46) were injected under control, aortic constriction and arterenol infusion in four dogs and under control conditions in two others. All microsphere injections were performed under stabilized conditions. It was found that coronary blood flow rose by 80% during aortic constriction and by 158% during arterenol infusion (P < 0.05). This increase in blood flow was not uniform throughout the heart, and higher increases were observed in the middle and apex regions of the left ventricle. Furthermore, under hypertension the increase in blood flow in LAD (left anterior descending) perfused territories was slightly higher than that in CFX (left circumflex) perfused territories

  2. Studies of Tracer Dispersion and Fluid Flow in Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Rage, T.

    1996-12-31

    This doctoral thesis explores the connection between the topology of a porous medium and its macroscopic transport properties and is based on computerized simulation. In porous media, both diffusion and convection contribute to the dispersion of a tracer and their combined effect is emphasized. The governing equations are solved numerically, using finite differences and Monte Carlo technique. The influence of finite Reynolds number on the outcome of echo-experiments is discussed. Comparing experiments and simulations it is found that nonlinear inertial forces lead to a visible deformation of a returned tracer at surprisingly small Reynolds numbers. In a study of tracer dispersion and fluid flow in periodic arrays of discs it is demonstrated that the mechanisms of mechanical dispersion in periodic media and in natural (non-periodic) porous media are essentially different. Measurements of the percolation probability distribution of a sandstone sample is presented. Local porosity theory predicts that this simple geometric function of a porous medium is of dominant importance for its macroscopic transport properties. It is demonstrated that many aspects of transport through fractures can be studied by using simple but realistic models and readily available computer resources. An example may be the transport of hydrocarbon fluids from the source rock to a reservoir. 165 refs., 44 figs., 1 table

  3. Effects of spinal cord stimulation on myocardial blood flow assessed by positron emission tomography in patients with refractory angina pectoris

    NARCIS (Netherlands)

    Hautvast, RWM; Blanksma, PK; DeJongste, MJL; Pruim, J; vanderWall, EE; Vaalburg, W; Lie, KI

    1996-01-01

    Spinal cord stimulation in angina pectoris increases exercise capacity and reduces both anginal attacks and ischemic electrocardiographic signs. This suggests an anti-ischemic action, perhaps through changes in myocardial blood flow. In 9 patients, regional myocardial blood flow was studied with

  4. Relationship between coronary contrast-flow quantitative flow ratio and myocardial ischemia assessed by SPECT MPI

    Energy Technology Data Exchange (ETDEWEB)

    Smit, Jeff M.; Rosendael, Alexander R. van; Jukema, J.W.; Delgado, Victoria; Bax, Jeroen J.; Scholte, Arthur J. [Leiden University Medical Center, Department of Cardiology, Leiden (Netherlands); Koning, Gerhard [Medis Medical Imaging Systems B.V., Leiden (Netherlands); Dibbets-Schneider, Petra [Leiden University Medical Center, Department of Nuclear Medicine, Leiden (Netherlands); Mertens, Bart J. [Leiden University Medical Center, Department of Medical Statistics, Leiden (Netherlands); Reiber, Johan H.C. [Medis Medical Imaging Systems B.V., Leiden (Netherlands); Leiden University Medical Center, Department of Radiology, Leiden (Netherlands)

    2017-10-15

    A new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called ''contrast-flow quantitative flow ratio (cQFR)''. Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). Patients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal. Two hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p <0.001). A good relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters. (orig.)

  5. A Connection Machine implementation of tracer particle flow visulization

    International Nuclear Information System (INIS)

    Salem, J.B.; Sethian, J.A.

    1989-01-01

    In this paper, the authors describe the implementation of an interactive visualization environment for computational fluid mechanics. The environment simulates the advection of tracer particles in a precomputed, time- varying flow velocity field. The environment mimics the physical laboratory by allowing near real-time interactive animation of the simulation. The environment provides a valuable set of tools for probing the underlying physics of a computational model and for comparing results with physical experiment. The paper presents the algorithms and discusses their realization on the Connection Machine CM-2 data parallel computer. Storage issues and the user interface are discussed. The authors demonstrate the environment using two dimensional simulated flow within a closed cavity. In a typical simulation, a sustained animation rate of 9 frames per second is achieved on a 8,192 processor CM-2

  6. A protective role of early collateral blood flow in patients with ST-segment elevation myocardial infarction.

    Science.gov (United States)

    Kim, Eun Kyoung; Choi, Jin-Ho; Song, Young Bin; Hahn, Joo-Yong; Chang, Sung-A; Park, Sung-Ji; Lee, Sang-Chol; Choi, Seung-Hyuk; Choe, Yeon Hyeon; Park, Seung Woo; Gwon, Hyeon-Cheol

    2016-01-01

    Conflict persists regarding whether the presence of early collateral blood flow to the infarct-related artery has an effective role in reducing infarct size and improving myocardial salvage in patients with ST-segment elevation myocardial infarction (STEMI). We sought to investigate the impact of the collateral circulation on myocardial salvage and infarct size in STEMI patients. In 306 patients who were diagnosed with STEMI and underwent cardiac magnetic resonance within 1 week after revascularization, initial collateral flow to the infarct-related artery was assessed by coronary angiography. Using cardiac magnetic resonance imaging, myocardial infarct size and salvage were measured. Among 247 patients with preprocedural Thrombolysis in Myocardial Infarction flow 0/1, 54 (22%) patients had good collaterals (Rentrop grade ≥ 2, Collateral Connection Score ≥ 2). Infarct size and area at risk were significantly smaller in patients with good collaterals than those with poor collaterals (infarct size: 17.1 ± 10.1 %LV vs 21.8 ± 10.5 %LV, P = .003, area at risk: 33.8 ± 16.8 %LV vs 38.8 ± 15.5 %LV, P = .039). There was a significant difference of myocardial salvage index between 2 groups (50.9% ± 15.0% vs 43.8% ± 18.5%, P = .005). Poor collateralization was an independent predictor for large infarct size (odd ratio 2.48 [1.28-4.80], P = .007). In patients with STEMI, the presence of well-developed collaterals to occluded coronary artery from the noninfarct vessel and its extent were independently associated with reduced infarct burden and improved myocardial salvage. Our results help explain why MI patients with well-developed collateralization have reduced mortality and morbidity. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    Science.gov (United States)

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted. © 2016 American Heart Association, Inc.

  8. Effect of liraglutide on myocardial glucose uptake and blood flow in stable chronic heart failure patients

    DEFF Research Database (Denmark)

    Nielsen, Roni; Jorsal, Anders; Iversen, Peter

    2017-01-01

    BACKGROUND: The glucagon-like peptide-1 analog liraglutide increases heart rate and may be associated with more cardiac events in chronic heart failure (CHF) patients. We studied whether this could be ascribed to effects on myocardial glucose uptake (MGU), myocardial blood flow (MBF) and MBF rese...

  9. In vivo measurement of myocardial protein turnover using an indicator dilution technique

    International Nuclear Information System (INIS)

    Revkin, J.H.; Young, L.H.; Stirewalt, W.S.; Dahl, D.M.; Gelfand, R.A.; Zaret, B.L.; Barrett, E.J.

    1990-01-01

    We applied a nondestructive tracer technique, previously developed for measuring skeletal muscle protein turnover, to the measurement of myocardial protein turnover in vivo. During a continuous infusion of L-[ring-2,6-3H]phenylalanine to anesthetized, overnight-fasted dogs, we measured the uptake of radiolabeled phenylalanine from plasma and the release of unlabeled phenylalanine from myocardial proteolysis using arterial and coronary sinus catheterization and analytic methods previously applied to skeletal muscle. Using these measurements, together with a model of myocardial protein synthesis that assumes rapid equilibration of tracer specific activity between myocardial phenylalanyl-tRNA and circulating phenylalanine, we estimated the rates of heart protein synthesis and degradation. The rate of heart protein synthesis was also estimated directly from the incorporation of labeled phenylalanine into tissue protein. The use of [3H]phenylalanine was compared with L-[1-14C]leucine in the measurement of heart protein turnover in dogs given simultaneous infusion of both tracers. Leucine uptake and release by the myocardium exceeded that of phenylalanine by 3.1 +/- 0.4- and 1.7 +/- 0.3-fold, respectively, consistent with leucine's 2.4-fold greater abundance in heart protein and its metabolism via other pathways. Phenylalanine is the preferred tracer for use with this method because of its limited metabolic fate in muscle. One theoretical limitation to the method, slow equilibration of circulating labeled phenylalanine with myocardial phenylalanyl-tRNA, was resolved by comparison of these specific activities after a 30-minute infusion of labeled phenylalanine in the rat. A second, empirical limitation involves precision in the measurement of the small decrements in phenylalanine specific activity that occur with each pass of blood through the coronary circulation

  10. Using environmental tracer data to identify deep-aquifer, long-term flow patterns and recharge distributions in the Surat Basin, Queensland, Australia

    Science.gov (United States)

    Siade, A. J.; Suckow, A. O.; Morris, R.; Raiber, M.; Prommer, H.

    2017-12-01

    The calibration of regional groundwater flow models, including those investigating coal-seam gas (CSG) impacts in the Surat Basin, Australia, are not typically constrained using environmental tracers, although the use of such data can potentially provide significant reductions in predictive uncertainties. These additional sources of information can also improve the conceptualisation of flow systems and the quantification of groundwater fluxes. In this study, new multi-tracer data (14C, 39Ar, 81Kr, and 36Cl) were collected for the eastern recharge areas of the basin and within the deeper Hutton and Precipice Sandstone formations to complement existing environmental tracer data. These data were used to better understand the recharge mechanisms, recharge rates and the hydraulic properties associated with deep aquifer systems in the Surat Basin. Together with newly acquired pressure data documenting the response to the large-scale reinjection of highly treated CSG co-produced water, the environmental tracer data helped to improve the conceptualisation of the aquifer system, forming the basis for a more robust quantification of the long-term impacts of CSG-related activities. An existing regional scale MODFLOW-USG groundwater flow model of the area was used as the basis for our analysis of existing and new observation data. A variety of surrogate modelling approaches were used to develop simplified models that focussed on the flow and transport behaviour of the deep aquifer systems. These surrogate models were able to represent sub-system behaviour in terms of flow, multi-environmental tracer transport and the observed large-scale hydrogeochemical patterns. The incorporation of the environmental tracer data into the modelling framework provide an improved understanding of the flow regimes of the deeper aquifer systems as well as valuable information on how to reduce uncertainties in hydraulic properties where there is little or no historical observations of hydraulic

  11. Models for tracer flow

    International Nuclear Information System (INIS)

    Zuber, A.

    1983-01-01

    A review and discussion is given of mathematical models used for interpretation of tracer experiments in hydrology. For dispersion model, different initial and boundary conditions are related to different injection and detection modes. Examples of applications of various models are described and commented. (author)

  12. Tracer filamentation at an unstable ocean front

    Science.gov (United States)

    Feng, Yen Chia; Mahadevan, Amala; Thiffeault, Jean-Luc; Yecko, Philip

    2017-11-01

    A front, where two bodies of ocean water with different physical properties meet, can become unstable and lead to a flow with high strain rate and vorticity. Phytoplankton and other oceanic tracers are stirred into filaments by such flow fields, as can often be seen in satellite imagery. The stretching and folding of a tracer by a two-dimensional flow field has been well studied. In the ocean, however, the vertical shear of horizontal velocity is typically two orders of magnitude larger than the horizontal velocity gradient. Theoretical calculations show that vertical shear alters the way in which horizontal strain affects the tracer, resulting in thin, sloping structures in the tracer field. Using a non-hydrostatic ocean model of an unstable ocean front, we simulate tracer filamentation to identify the effect of vertical shear on the deformation of the tracer. In a complementary laboratory experiment, we generate a simple, vertically sheared strain flow and use dye and particle image velocimetry to quantify the filamentary structures in terms of the strain and shear. We identify how vertical shear alters the tracer filaments and infer how the evolution of tracers in the ocean will differ from the idealized two-dimensional paradigm. Support of NSF DMS-1418956 is acknowledged.

  13. Myocardial imaging by direct injection of thallium-201 into coronary artery

    International Nuclear Information System (INIS)

    Sugihara, Hiroki; Inagaki, Suetsugu; Kubota, Yasushi

    1988-01-01

    Myocardial perfusion images were evaluated by direct injection of Thallium (Tl)-201 into coronary artery. Approximately 0.5 - 1 mCi of Tl-201 were instilled into the right coronary artery and/or the left coronary artery after coronary arteriography. Three images were obtained in the anterior, left anterior oblique and left lateral projections. Myocardial perfusion images of single photon emission computed tomography were also acquired in some patients. An image of supreme quality could be obtained in spite of small dose of Tl-201 since there was a lack of interference from background activity. Myocardial perfusion images corresponded to areas which were supplied by left or right coronary artery respectively. And the regional myocardial blood flow distribution of a coronary artery bypass graft could be revealed by instilling Tl-201 into the graft. Further, contribution of collateral channels to myocardial perfusion was showed. Not only left ventricle but also right ventricle was clearly visualized by injection of Tl-201 into right coronary artery. But in a case with arrhythmogenic right ventricular dysplasia, there was an area of decreased tracer uptake in the apex of the right ventricle which was identified as the site of dysplasia by electrophysiologic study. We conclude that direct injection of Tl-201 into coronary artery is an useful method to clarify the correlation between coronary anatomical findings and coronary perfusion and contribution of collaterals to myocardial perfusion, and also to detect the right ventricular myopathic site. (author)

  14. Myocardial blood flow assessment with {sup 82}rubidium-PET imaging in patients with left bundle branch block

    Energy Technology Data Exchange (ETDEWEB)

    Falcao, Andrea; Chalela, William; Giorgi, Maria Clementina; Imada, Rodrigo; Soares Junior, Jose; Do Val, Renata; Oliveira, Marco Antonio; Izaki, Marisa; Kalil Filho, Roberto; Meneghetti, Jose C., E-mail: andrea.falcao@incor.usp.br [Universidade de Sao Paulo (InCor/USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Instituto do Coracao

    2015-11-15

    Objectives: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. Objective: we sought to investigate rubidium-82 ({sup 82}Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. Methods: thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress {sup 82}Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal {sup 82}Rb-positron emission tomography studies and without left bundle branch block (GII). Results: stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p>0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). Conclusion: the data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by {sup 82}Rb-positron emission tomography imaging may be useful in identifying coronary artery

  15. Increased myocardial infarct size because of reduced coronary collateral blood flow in beagles

    International Nuclear Information System (INIS)

    Uemura, N.; Knight, D.R.; Shen, Y.T.; Nejima, J.; Cohen, M.V.; Thomas, J.X. Jr.; Vatner, S.F.

    1989-01-01

    Effects of permanent left circumflex coronary artery occlusion (CAO) were examined in conscious purebred beagles and mongrel dogs, instrumented with miniature left ventricular (LV) pressure gauges, wall thickness gauges in the ischemic zone, catheters in left atrium and aorta, and snares around the left circumflex coronary artery. Blood flow was measured using the radioactive microsphere technique before CAO and at 5 min, 1, 3, and 24 h after CAO. Although CAO reduced myocardial blood flow similarly in beagles and mongrels, significantly less (P less than 0.05) recovery of myocardial blood flow was observed over the following 24-h period in beagles. Infarct size, as determined by triphenyltetrazolium chloride and expressed as percentage of area at risk, was larger (P less than 0.05) in beagles (62.0 ± 5.1%) than mongrels (42.5 ± 4.2%). Thus beagles do not tolerate ischemia as well as mongrel dogs and possess fewer functional coronary collaterals resulting in larger infarcts after CAO

  16. Noninvasive determination of myocardial blood flow, oxygen consumption and efficiency in normal humans by carbon-11 acetate positron emission tomography imaging

    International Nuclear Information System (INIS)

    Porenta, G.; Cherry, S.; Czernin, J.; Brunken, R.; Kuhle, W.; Hashimoto, T.; Schelbert, H.R.

    1999-01-01

    The aims of this study were: (1) to measure noninvasively and near simultaneously myocardial blood flow, oxygen consumption, and contractile function and (2) to analyze myocardial energy expenditure and efficiency at rest and during dobutamine stress in normal humans. Dynamic and gated carbon-11 acetate positron emission tomography (PET) imaging was performed in 11 normal subjects. The initial uptake of 11 C-acetate was measured to estimate myocardial blood flow. Oxygen consumption was derived from the monoexponential slope of the 11 C-clearance curve recorded during myocardial washout. ECG-gated systolic and diastolic images were acquired during the peak myocardial 11 C activity to measure left ventricular radius, myocardial wall thickness, and long axis length. Myocardial oxygen consumption and parameters of cardiac geometry were used to determine myocardial energetics and cardiac efficiency by tension-area area analysis. Myocardial blood flow averaged 0.8±0.06 ml min -1 g -1 at rest and 1.48±0.15 ml min -1 g -1 during dobutamine stress. Oxygen delivery and consumption were 151±13 and 88±15 μl O 2 min -1 g -1 at rest and increased to 291±31 and 216±31 μl O 2 min -1 g -1 , respectively, during pharmacological stress (P 11 C acetate imaging provides the unique capability to study noninvasively determinants of myocardial energy delivery, expenditure, and efficiency. (orig.)

  17. Relationship between HgbA1c and myocardial blood flow reserve in patients with type 2 diabetes mellitus: noninvasive assessment using real-time myocardial perfusion echocardiography.

    Science.gov (United States)

    Huang, Runqing; Abdelmoneim, Sahar S; Nhola, Lara F; Mulvagh, Sharon L

    2014-01-01

    To study the relationship between glycosylated hemoglobin (HgbA1c) and myocardial perfusion in type 2 diabetes mellitus (T2DM) patients, we prospectively enrolled 24 patients with known or suspected coronary artery disease (CAD) who underwent adenosine stress by real-time myocardial perfusion echocardiography (RTMPE). HgbA1c was measured at time of RTMPE. Microbubble velocity (β min(-1)), myocardial blood flow (MBF, mL/min/g), and myocardial blood flow reserve (MBFR) were quantified. Quantitative MCE analysis was feasible in all patients (272/384 segments, 71%). Those with HgbA1c > 7.1% had significantly lower βreserve and MBFR than those with HgbA1c ≤ 7.1% (P relationship was not significant (r = -0.117, P = 0.129). Using a MBFR cutoff value > 2 as normal, HgbA1c > 7.1% significantly increased the risk for abnormal MBFR, (adjusted odds ratio: 1.92, 95% CI: 1.12-3.35, P = 0.02). Optimal glycemic control is associated with preservation of MBFR as determined by RTMPE, in T2DM patients at risk for CAD.

  18. Transmural distribution of myocardial infarction: difference between the right and left ventricles in a canine model

    International Nuclear Information System (INIS)

    Ohzono, K.; Koyanagi, S.; Urabe, Y.; Harasawa, Y.; Tomoike, H.; Nakamura, M.

    1986-01-01

    The evolution of myocardial infarction 24 hours after ligating both the right coronary artery and the obtuse marginal branch of the left circumflex coronary artery was examined in 33 anesthetized dogs. Postmortem coronary angiography and a tracer microsphere technique were used to determine risk areas and their collateral blood flows, respectively. The mean weight of the risk areas was 11.3 +/- 0.5 g (mean +/- SEM) in the right ventricle and 10.5 +/- 0.9 g in the left ventricle (NS). The weight of infarcted tissue was 5.7 +/- 0.7 g in the right ventricle and 5.2 +/- 0.9 g in the left ventricle (NS). In both ventricles, infarct weight was linearly related to risk area size, and the percent of risk area necrosis was inversely correlated with the extent of collateral flow at 24 hours of coronary ligation, defined as the mean myocardial blood flow inside the central risk area. Ratios of infarct to risk area between the subendocardial and subepicardial layers were 0.76 +/- 0.06 and 0.28 +/- 0.05 in the right and left ventricles, respectively (p less than 0.01, between ventricles, n = 31), which coincided well with subendocardial-to-subepicardial-flow ratios at 24 hours, ie, 0.86 +/- 0.04 in the right ventricle and 0.32 +/- 0.06 in the left ventricle (p less than 0.01). The regional distribution of myocardial infarction correlated well with flow distribution inside the risk area; the slope of these relations was similar between the subendocardium and subepicardium in the right ventricle, whereas in the left ventricle it was larger in the subendocardium than in the subepicardium. Thus, in the dog, the inherent change in the regional distribution of coronary collateral blood flow is an important modifier in the evolution of myocardial infarction, especially in the left ventricle

  19. Myocardial temperature variation: effect on regional function and coronary flow in dogs

    International Nuclear Information System (INIS)

    D'Ambra, M.N.; Magrassi, P.; Lowenstein, E.; Kyo, S.; Austen, W.G.; Buckley, M.J.; LaRaia, P.J.

    1987-01-01

    Incremental changes in the temperature (28-42.5 0 C) of the anterior left ventricular wall in a canine, working, beating right heart bypass preparation (constant preload, afterload, and heart rate) were produced to measure the effect of regional temperature on myocardial function and blood flow. Circumferential-axis segment lengths were measured with sonomicrometry in both the temperature-varied, left-anterior descending coronary artery (LAD)-supplied myocardium and the normothermic (38 0 C) circumflex-supplied myocardium. Fast thermistors (time constant 0 C), regional systolic shortening decreased 42.2 +/- 10% at 41 0 C and increased 23.3 +/- 6% at 31 0 C. There was no significant change in coronary blood flow or distribution at the three temperatures. Pressure-length areas varied inversely with myocardial temperature. These data demonstrate that there is a reversible inverse relationship between midwall T and ventricular function when heart rate, preload, and afterload are controlled

  20. Transient integral boundary layer method to calculate the translesional pressure drop and the fractional flow reserve in myocardial bridges

    Directory of Open Access Journals (Sweden)

    Möhlenkamp Stefan

    2006-06-01

    Full Text Available Abstract Background The pressure drop – flow relations in myocardial bridges and the assessment of vascular heart disease via fractional flow reserve (FFR have motivated many researchers the last decades. The aim of this study is to simulate several clinical conditions present in myocardial bridges to determine the flow reserve and consequently the clinical relevance of the disease. From a fluid mechanical point of view the pathophysiological situation in myocardial bridges involves fluid flow in a time dependent flow geometry, caused by contracting cardiac muscles overlying an intramural segment of the coronary artery. These flows mostly involve flow separation and secondary motions, which are difficult to calculate and analyse. Methods Because a three dimensional simulation of the haemodynamic conditions in myocardial bridges in a network of coronary arteries is time-consuming, we present a boundary layer model for the calculation of the pressure drop and flow separation. The approach is based on the assumption that the flow can be sufficiently well described by the interaction of an inviscid core and a viscous boundary layer. Under the assumption that the idealised flow through a constriction is given by near-equilibrium velocity profiles of the Falkner-Skan-Cooke (FSC family, the evolution of the boundary layer is obtained by the simultaneous solution of the Falkner-Skan equation and the transient von-Kármán integral momentum equation. Results The model was used to investigate the relative importance of several physical parameters present in myocardial bridges. Results have been obtained for steady and unsteady flow through vessels with 0 – 85% diameter stenosis. We compare two clinical relevant cases of a myocardial bridge in the middle segment of the left anterior descending coronary artery (LAD. The pressure derived FFR of fixed and dynamic lesions has shown that the flow is less affected in the dynamic case, because the distal

  1. Radioisotope tracer applications in industry

    International Nuclear Information System (INIS)

    Rao, S.M.

    1987-01-01

    Radioisotope tracers have many advantages in industrial trouble-shooting and studies on process kinetics. The applications are mainly of two types: one leading to qualitative (Yes or No type) information and the other to quantitative characterisation of flow processes through mass balance considerations and flow models. ''Yes or No'' type methods are mainly used for leakage and blockage locations in pipelines and in other industrial systems and also for location of water seepage zones in oil wells. Flow measurements in pipelines and mercury inventory in electrolytic cells are good examples of tracer methods using the mass balance approach. Axial dispersion model and Tanks-in-Series model are the two basic flow models commonly used with tracer methods for the characterisation of kinetic processes. Examples include studies on flow processes in sugar crystallisers as well as in a precalcinator in a cement plant. (author). 18 figs

  2. Myocardial blood flow quantification for evaluation of coronary artery disease by positron emission tomography, cardiac magnetic resonance imaging, and computed tomography.

    Science.gov (United States)

    Waller, Alfonso H; Blankstein, Ron; Kwong, Raymond Y; Di Carli, Marcelo F

    2014-05-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging, and computed tomography, and its emerging clinical applications.

  3. Tracer dispersion - experiment and CFD

    International Nuclear Information System (INIS)

    Zitny, R.

    2004-01-01

    Description of tracer distribution by means of dispersion models is a method successfully used in process engineering for fifty years. Application of dispersion models in reactor engineering for characterization of flows in column apparatus, heat exchangers, etc. is summarized and experimental tracer techniques as well as CFD methods for dispersion coefficients evaluation are discussed. Possible extensions of thermal axial dispersion model (ADM) and a core-wall ADM model suitable for description of tracer dispersion in laminar flows are suggested as well as CFD implementation as 1D finite elements. (author)

  4. Fractional flow reserve-guided management in stable coronary disease and acute myocardial infarction: recent developments

    Science.gov (United States)

    Berry, Colin; Corcoran, David; Hennigan, Barry; Watkins, Stuart; Layland, Jamie; Oldroyd, Keith G.

    2015-01-01

    Coronary artery disease (CAD) is a leading global cause of morbidity and mortality, and improvements in the diagnosis and treatment of CAD can reduce the health and economic burden of this condition. Fractional flow reserve (FFR) is an evidence-based diagnostic test of the physiological significance of a coronary artery stenosis. Fractional flow reserve is a pressure-derived index of the maximal achievable myocardial blood flow in the presence of an epicardial coronary stenosis as a ratio to maximum achievable flow if that artery were normal. When compared with standard angiography-guided management, FFR disclosure is impactful on the decision for revascularization and clinical outcomes. In this article, we review recent developments with FFR in patients with stable CAD and recent myocardial infarction. Specifically, we review novel developments in our understanding of CAD pathophysiology, diagnostic applications, prognostic studies, clinical trials, and clinical guidelines. PMID:26038588

  5. Quantification of myocardial blood flow with {sup 82}Rb positron emission tomography: clinical validation with {sup 15}O-water

    Energy Technology Data Exchange (ETDEWEB)

    Prior, John O.; Allenbach, Gilles; Bischof Delaloye, Angelika [Centre Hospitalier Universitaire Vaudois and University of Lausanne, Nuclear Medicine Department, Lausanne (Switzerland); Valenta, Ines; Burger, Cyrill [Cardiac Imaging, Department of Radiology, Zurich (Switzerland); Kosinski, Marek [Centre Hospitalier Universitaire Vaudois and University of Lausanne, Nuclear Medicine Department, Lausanne (Switzerland); Centre Hospitalier Universitaire Vaudois and University of Lausanne, University Institute for Radiation Physics, Lausanne (Switzerland); Verdun, Francis R. [Centre Hospitalier Universitaire Vaudois and University of Lausanne, University Institute for Radiation Physics, Lausanne (Switzerland); Kaufmann, Philipp A. [Cardiac Imaging, Department of Radiology, Zurich (Switzerland); University of Zurich, Zurich Centre for Integrative Human Physiology (ZIHP), Zurich (Switzerland)

    2012-06-15

    Quantification of myocardial blood flow (MBF) with generator-produced {sup 82}Rb is an attractive alternative for centres without an on-site cyclotron. Our aim was to validate {sup 82}Rb-measured MBF in relation to that measured using {sup 15}O-water, as a tracer 100% of which can be extracted from the circulation even at high flow rates, in healthy control subject and patients with mild coronary artery disease (CAD). MBF was measured at rest and during adenosine-induced hyperaemia with {sup 82}Rb and {sup 15}O-water PET in 33 participants (22 control subjects, aged 30 {+-} 13 years; 11 CAD patients without transmural infarction, aged 60 {+-} 13 years). A one-tissue compartment {sup 82}Rb model with ventricular spillover correction was used. The {sup 82}Rb flow-dependent extraction rate was derived from {sup 15}O-water measurements in a subset of 11 control subjects. Myocardial flow reserve (MFR) was defined as the hyperaemic/rest MBF. Pearson's correlation r, Bland-Altman 95% limits of agreement (LoA), and Lin's concordance correlation {rho} {sub c} (measuring both precision and accuracy) were used. Over the entire MBF range (0.66-4.7 ml/min/g), concordance was excellent for MBF (r = 0.90, [{sup 82}Rb-{sup 15}O-water] mean difference {+-} SD = 0.04 {+-} 0.66 ml/min/g, LoA = -1.26 to 1.33 ml/min/g, {rho} {sub c} = 0.88) and MFR (range 1.79-5.81, r = 0.83, mean difference = 0.14 {+-} 0.58, LoA = -0.99 to 1.28, {rho} {sub c} = 0.82). Hyperaemic MBF was reduced in CAD patients compared with the subset of 11 control subjects (2.53 {+-} 0.74 vs. 3.62 {+-} 0.68 ml/min/g, p = 0.002, for {sup 15}O-water; 2.53 {+-} 1.01 vs. 3.82 {+-} 1.21 ml/min/g, p = 0.013, for {sup 82}Rb) and this was paralleled by a lower MFR (2.65 {+-} 0.62 vs. 3.79 {+-} 0.98, p = 0.004, for {sup 15}O-water; 2.85 {+-} 0.91 vs. 3.88 {+-} 0.91, p = 0.012, for {sup 82}Rb). Myocardial perfusion was homogeneous in 1,114 of 1,122 segments (99.3%) and there were no differences in MBF among the

  6. Contribution of radioactive tracers to sediment transport study in fluvial flows

    International Nuclear Information System (INIS)

    Wilson Junior, G.

    1995-01-01

    The uses of radioactive tracers in sediment transport studies are presented in this report to evidence the importance of: Open channel researches, to describe field applications in waterways; Simultaneous utilization of classical methods and radiotracer techniques, in fluvial and estuarine environments; Development of radiotracers techniques applied in dynamic sedimentology. The report illustrated with some experiments carried out in Brazil and France, in open channel and natural flows. (author). 5 refs, 4 figs

  7. Effect of motion-induced PET-CT misalignment on cardiac function and myocardial blood flow measured using dynamic 15O-water PET

    DEFF Research Database (Denmark)

    Lubberink, Mark; Ebrahimi, M; Harms, Hans

    -CT misalignment on MBF, transmural MBF (MBFt), perfusable tissue fraction (PTF), cardiac output (CO), stroke volume (SV) and left-ventricular ejection fraction (LVEF) based on dynamic 15O-water scans. Methods: 10 patients underwent 6 min PET scans after injection of 400 MBq 15O-water at rest and during adenosine......Aim: Motion-induced PET-CT misalignment artifacts are common in myocardial blood flow (MBF) measurements with 82Rb and 13N-ammonia. For 15O-water, MBF is based on the clearance rate rather than uptake of the tracer. The clearance rate is determined by the shape of the time-activity curve, not its...... amplitude, and is thus not affected by attenuation correction errors. Hence, misalignment is hypothesized not to affect 15O-water-based MBF to any large extent, but it may affect cardiac function measures derived from 15O-water scans. The aim of the present work was to assess the effect of PET...

  8. Dual myocardial scintigraphic imaging using 123I-BMIPP and 201Tl in patients with Duchenne's progressive muscular dystrophy

    International Nuclear Information System (INIS)

    Sasaki, Akira

    1996-01-01

    Dual single photon emission computed tomography (SPECT) was performed in 30 patients with Duchenne's muscular dystrophy (DMD) using 201 thallium (Tl) for myocardial perfusion 123 I-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) for myocardial fatty acid metabolism scintigraphy. The left ventricle was divided into 9 regions, and accumulation of the radiotracers was assessed visually for each region to calculate defect score for each tracer. There was some degree of decrease in the myocardial accumulation of both tracers in all DMD patients. Reduced accumulation was most common at the apex (BMIPP, 70%; Tl, 63%), followed by the posterior wall, lateral wall, and anterior wall. It was less common on the apical side of the ventricular septum for both tracers (BMIPP, 3%; Tl, 17%). Accumulation of Tl was lower than BMIPP in 18/30 patients (60%) and higher in 9 (30%), while both tracers showed equal accumulation in 3 (10%). BMIPP showed higher accumulation than Tl in all regions but the septum. A significant negative correlation was found between the defect scores for both tracers and the left ventricular ejection fraction (LVEF) (r=-0.629 for Tl; r=-0.567 for BMIPP). The strongest negative correlation was that between the sum of the Tl and BMIPP defect scores and the LVEF (r=-0.681). Dual SPECT myocardial scintigraphy with Tl and BMIPP provided an accurate evaluation of the progression of cardiac lesions in DMD by detecting abnormalities of the myocardial metabolism of each substance thereby enabling the assessment of left ventricular function. (author)

  9. Regional myocardial flow and capillary permeability-surface area products are nearly proportional.

    Science.gov (United States)

    Caldwell, J H; Martin, G V; Raymond, G M; Bassingthwaighte, J B

    1994-08-01

    Analyses of data on the transcapillary exchange and cellular uptake in the normal heart have generally been based on the assumption that local membrane conductances and volumes of distribution are everywhere the same. The question is whether such an assumption is justified in view of the marked (sixfold) heterogeneity of local blood flows per gram tissue. The method was to estimate both flow and capillary membrane permeability-surface area products (PS) locally in the heart. For each of five dogs running on a sloped treadmill, the deposition of tracer microspheres and of [131I]iodophenylpentadecanoic acid (IPPA), after left atrial injection, was determined in 256 pieces of left ventricular myocardium by killing the animals at approximately 100 s after radiotracer injection. A hydraulic occluder stopped the flow to a portion of the myocardium supplied by the left circumflex coronary artery 30 s before tracer injection. Regional flows ranged from 0.1 to 7.0 ml.g-1.min-1. IPPA extractions ranged from 20 to 49%. Using the known flows, we assumed the applicability of an axially distributed blood-tissue exchange model to estimate the PS for the capillary (PSc) and the parenchymal cell. It was impossible to explain the data if the PSc values for membrane transport were uniform throughout the organ. Rather, the only reasonable descriptors of the data required that local PSc values increase with local flow, almost in proportion. Current methods of analysis using data based on deposition methods need to be revised to take into account the near proportionality of PS to flow for at least some substrates.

  10. Unsaturated water flow and tracer transport modeling with Alliances

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, Alina, E-mail: alina.constantin@nuclear.ro [Institute for Nuclear Research, Campului Str, No. 1, PO Box 78, Postal Code 115400 Mioveni, Arges County (Romania); Genty, Alain, E-mail: alain.genty@cea.fr [CEA Saclay, DM2S/SFME/LSE, Gif-sur-Yvette 91191 cedex (France); Diaconu, Daniela; Bucur, Crina [Institute for Nuclear Research, Campului Str, No. 1, PO Box 78, Postal Code 115400 Mioveni, Arges County (Romania)

    2013-12-15

    Highlights: • Simulation of water flow and solute transport at Saligny site, Romania was done. • Computation was based on the available experimental data with Alliances platform. • Very good results were obtained for the saturation profile in steady state. • Close fit to experimental data for saturation profile at 3 m in transient state. • Large dispersivity coefficients were fitted to match tracer experiment. - Abstract: Understanding water flow and solute transport in porous media is of central importance in predicting the radionuclide fate in the geological environment, a topic of interest for the performance and safety assessment studies for nuclear waste disposal. However, it is not easy to predict transport properties in real systems because they are geologically heterogeneous from the pore scale upwards. This paper addresses the simulation of water flow and solute transport in the unsaturated zone of the Saligny site, the potential location for the Romanian low and intermediate level waste (LILW) disposal. Computation was based on the current available experimental data for this zone and was performed within Alliances, a software platform initially jointly developed by French organizations CEA, ANDRA and EDF. The output of the model developed was compared with the measured values in terms of saturation profile of the soil for water movement, in both steady and transient state. Very good results were obtained for the saturation profile in steady state and a close fit of the simulation over experimental data for the water saturation profile at a depth of 3 m in transient state. In order to obtain information regarding the solute migration in depth and the solute lateral dispersion, a tracer test was launched on site and dispersivity coefficients of the solute were fitted in order to match the experimental concentration determined on samples from different locations of the site. Results much close to the experiment were obtained for a longitudinal

  11. Persistent Tracers of Historic Ice Flow in Glacial Stratigraphy near Kamb Ice Stream, West Antarctica

    OpenAIRE

    Holschuh, Nicholas; Christianson, Knut; Conway, Howard; Jacobel, Robert W.; Welch, Brian C.

    2018-01-01

    Variations in properties controlling ice flow (e.g., topography, accumulation rate, basal friction) are recorded by structures in glacial stratigraphy. When anomalies that disturb the stratigraphy are fixed in space, the structures they produce advect away from the source, and can be used to trace flow pathways and reconstruct ice-flow patterns of the past. Here we provide an example of one of these persistent tracers: a prominent unconformity in the glacial layering that originates at Mt. Re...

  12. On the numerical simulation of tracer flows in porous media

    International Nuclear Information System (INIS)

    Aquino, J.; Pereira, F.; Amaral Souto, H.P.; Francisco, A.S.

    2007-01-01

    We discuss in detail a new Lagrangian, locally conservative procedure which has been proposed for the numerical solution of linear transport problems in porous media. The new scheme is computationally efficient, virtually free of numerical diffusion, and can be applied to investigate numerically the time evolution of radionuclide contaminant plumes. Results of two-dimensional simulations of tracer flows will be presented to show the influence on the computed solutions of distinct interpolation functions for evaluating the velocity field at any position of the physical domain, as required by the Lagrangian scheme. (author)

  13. Field tracer investigation of unsaturated zone flow paths and mechanisms in agricultural soils of northwestern Mississippi, USA

    Science.gov (United States)

    Perkins, K.S.; Nimmo, J.R.; Rose, C.E.; Coupe, R.H.

    2011-01-01

    In many farmed areas, intensive application of agricultural chemicals and withdrawal of groundwater for irrigation have led to water quality and supply issues. Unsaturated-zone processes, including preferential flow, play a major role in these effects but are not well understood. In the Bogue Phalia basin, an intensely agricultural area in the Delta region of northwestern Mississippi, the fine-textured soils often exhibit surface ponding and runoff after irrigation and rainfall as well as extensive surface cracking during prolonged dry periods. Fields are typically land-formed to promote surface flow into drainage ditches and streams that feed into larger river ecosystems. Downward flow of water below the root zone is considered minimal; regional groundwater models predict only 5% or less of precipitation recharges the heavily used alluvial aquifer. In this study transport mechanisms within and below the root zone of a fallow soybean field were assessed by performing a 2-m ring infiltration test with tracers and subsurface monitoring instruments. Seven months after tracer application, 48 continuous cores were collected for tracer extraction to define the extent of water movement and quantify preferential flow using a mass-balance approach. Vertical water movement was rapid below the pond indicating the importance of vertical preferential flow paths in the shallow unsaturated zone, especially to depths where agricultural disturbance occurs. Lateral flow of water at shallow depths was extensive and spatially non-uniform, reaching up to 10. m from the pond within 2. months. Within 1. month, the wetting front reached a textural boundary at 4-5. m between the fine-textured soil and sandy alluvium, now a potential capillary barrier which, prior to extensive irrigation withdrawals, was below the water table. Within 10. weeks, tracer was detectable at the water table which is presently about 12. m below land surface. Results indicate that 43% of percolation may be through

  14. Properties of iopamidol-incorporated poly(vinyl alcohol) microparticle as an X-ray imaging flow tracer.

    Science.gov (United States)

    Ahn, Sungsook; Jung, Sung Yong; Lee, Jin Pyung; Lee, Sang Joon

    2011-02-10

    We have recently reported on poly(vinyl alcohol) microparticles containing X-ray contrast agent, iopamidol, designed as a flow tracer working in synchrotron X-ray imaging ( Biosens. Bioelectron. 2010 , 25 , 1571 ). Although iopamidol is physically encapsulated in the microparticles, it displays a great contrast enhancement and stable feasibility in in vitro human blood pool. Nonetheless, a direct relation between the absolute amount of incorporated iopamidol and the enhancement in imaging efficiency was not observed. In this study, physical properties of the designed microparticle are systematically investigated experimentally with theoretical interpretation to correlate an enhancement in X-ray imaging efficiency. The compositional ratio of X-ray contrast agent in polymeric microparticle is controlled as 1/1 and 10/1 [contrast agent/polymer microparticle (w/w)] with changed degree of cross-linkings. Flory-Huggins interaction parameter (χ), retractive force (τ) and degree of swelling of the designed polymeric microparticles are investigated. In addition, the hydrodynamic size (D(H)) and ζ-potential are evaluated in terms of environment responsiveness. The physical properties of the designed flow tracer microparticles under a given condition are observed to be strongly related with the X-ray absorption efficiency, which are also supported by the Beer-Lambert-Bouguer law. The designed microparticles are almost nontoxic with a reasonable concentration and time period, enough to be utilized as a flow tracer in various biomedical applications. This study would contribute to the basic understanding on the physical property connected with the imaging efficiency of contrast agents.

  15. Reduction of the influence of the liver uptake to the myocardial uptake on technetium-99m myocardial SPECT. Usefulness and problems of a mask processing method

    Energy Technology Data Exchange (ETDEWEB)

    Takaki, Akihiro; Okada, Kazuhiro; Urata, Johji; Matsuda, Hirofumi; Takao, Yuji [Saiseikai Kumamoto Hospital (Japan)

    1999-07-01

    The aim of this study is to evaluate the usefulness of a mask processing method for obtaining the true myocardial tracer distribution by eliminating the influence of the liver uptake to the myocardial uptake on myocardial SPECT images by using technetium-99m ({sup 99m}Tc) blood flow agents. A SPECT imaging was performed with a two-head SPECT system (GCA-7200A/DI) in both phantom and clinical studies. The mask processing method was applied to the reconstructed and projection images. The phantom consisted of heart, lung, liver and spine. A defect was located in the inferior wall of the left ventricle and other parts of the heart and liver were filled with {sup 99m}Tc solution. For clinical study 10 patients with difficulty in the interpretation of the inferior wall were selected for the evaluation of usefulness of the mask method. In the phantom study, the mask processing method applied to the reconstructed images was able to remove the overlapped liver from the heart, but was not able to remove the influence of the liver uptake to the myocardial uptake. Nevertheless, the mask processing method applied to the projection images successfully eliminated not only the overlapped liver but also the influence of the liver uptake to the myocardial uptake. In the clinical study, the liver uptake could be removed from the uptake in the inferior wall in 8 of 10 patients with the mask processing methods. In 2 patients, the overlapped liver uptake could not be eliminated from the uptake in the inferior wall because the distance between the liver and heart was too short. The mask processing method applied to the projection images was thought to be superior to that applied to the reconstruction images in both phantom and clinical studies. The mask processing method, especially applied to the projection images, seems to be useful for the elimination of the liver uptake from the inferior wall of the myocardium on myocardial SPECT images using {sup 99m}Tc blood flow agents. (author)

  16. Reduction of the influence of the liver uptake to the myocardial uptake on technetium-99m myocardial SPECT. Usefulness and problems of a mask processing method

    International Nuclear Information System (INIS)

    Takaki, Akihiro; Okada, Kazuhiro; Urata, Johji; Matsuda, Hirofumi; Takao, Yuji

    1999-01-01

    The aim of this study is to evaluate the usefulness of a mask processing method for obtaining the true myocardial tracer distribution by eliminating the influence of the liver uptake to the myocardial uptake on myocardial SPECT images by using technetium-99m ( 99m Tc) blood flow agents. A SPECT imaging was performed with a two-head SPECT system (GCA-7200A/DI) in both phantom and clinical studies. The mask processing method was applied to the reconstructed and projection images. The phantom consisted of heart, lung, liver and spine. A defect was located in the inferior wall of the left ventricle and other parts of the heart and liver were filled with 99m Tc solution. For clinical study 10 patients with difficulty in the interpretation of the inferior wall were selected for the evaluation of usefulness of the mask method. In the phantom study, the mask processing method applied to the reconstructed images was able to remove the overlapped liver from the heart, but was not able to remove the influence of the liver uptake to the myocardial uptake. Nevertheless, the mask processing method applied to the projection images successfully eliminated not only the overlapped liver but also the influence of the liver uptake to the myocardial uptake. In the clinical study, the liver uptake could be removed from the uptake in the inferior wall in 8 of 10 patients with the mask processing methods. In 2 patients, the overlapped liver uptake could not be eliminated from the uptake in the inferior wall because the distance between the liver and heart was too short. The mask processing method applied to the projection images was thought to be superior to that applied to the reconstruction images in both phantom and clinical studies. The mask processing method, especially applied to the projection images, seems to be useful for the elimination of the liver uptake from the inferior wall of the myocardium on myocardial SPECT images using 99m Tc blood flow agents. (author)

  17. Chemical Tracer Methods: Chapter 7

    Science.gov (United States)

    Healy, Richard W.

    2017-01-01

    Tracers have a wide variety of uses in hydrologic studies: providing quantitative or qualitative estimates of recharge, identifying sources of recharge, providing information on velocities and travel times of water movement, assessing the importance of preferential flow paths, providing information on hydrodynamic dispersion, and providing data for calibration of water flow and solute-transport models (Walker, 1998; Cook and Herczeg, 2000; Scanlon et al., 2002b). Tracers generally are ions, isotopes, or gases that move with water and that can be detected in the atmosphere, in surface waters, and in the subsurface. Heat also is transported by water; therefore, temperatures can be used to trace water movement. This chapter focuses on the use of chemical and isotopic tracers in the subsurface to estimate recharge. Tracer use in surface-water studies to determine groundwater discharge to streams is addressed in Chapter 4; the use of temperature as a tracer is described in Chapter 8.Following the nomenclature of Scanlon et al. (2002b), tracers are grouped into three categories: natural environmental tracers, historical tracers, and applied tracers. Natural environmental tracers are those that are transported to or created within the atmosphere under natural processes; these tracers are carried to the Earth’s surface as wet or dry atmospheric deposition. The most commonly used natural environmental tracer is chloride (Cl) (Allison and Hughes, 1978). Ocean water, through the process of evaporation, is the primary source of atmospheric Cl. Other tracers in this category include chlorine-36 (36Cl) and tritium (3H); these two isotopes are produced naturally in the Earth’s atmosphere; however, there are additional anthropogenic sources of them.

  18. Are microbubbles free flowing tracers through the Myocardium? Comparison of indicator-dilution curves obtained from dye dilution and echo contrast using harmonic power Doppler imaging.

    Science.gov (United States)

    Tiemann, K; Schlosser, T; Pohl, C; Bimmel, D; Wietasch, G; Hoeft, A; Likungu, J; Vahlhaus, C; Kuntz, S; Nanda, N C; Becher, H; Lüderitz, B

    2000-01-01

    Harmonic power Doppler imaging (H-PDI) has been introduced into the field of contrast echocardiography as a contrast-specific imaging modality. However, there has been considerable skepticism as to whether H-PDI would be quantifiable, because it depends on the destruction of microbubbles and has more complex signal processing than gray scale imaging. The aim of the present study was to evaluate the relationship between the concentration of microbubbles and the resulting H-PDI signals even under conditions where bubble destruction is most likely. Furthermore, we evaluated whether microbubbles of Levovist freely pass the microcirculation, which is a prerequisite for the assessment of myocardial blood flow. A strong positive correlation was found between the H-PDI signals and the amount of microbubbles up to the onset of acoustic shadowing (r = 0. 968, Pgreen (ICG) in both a flow phantom and a working heart setup. The mean transit times (MTTs) through the myocardium of both agents were compared after a bolus injection into the left coronary artery. A close correlation was observed between 1/MTT and flow in both setups (r>0.98, Pgreen. We conclude that microbubbles fulfill the prerequisites of free flowing tracers through the myocardium. Furthermore, H-PDI technology allows a reliable assessment of time-concentration curves of air-filled microbubbles up to the onset of acoustic shadowing.

  19. Doublet Tracer Testing in Klamath Falls, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Gudmundsson, J S; Johnson, S E; Horne, R N; Jackson, P B [Pet. Eng. Dept., Stanford University; Culver, G G [Geo-Heat Center, Oregon Institute of Technology, Klamath Falls, OR

    0000-12-30

    A tracer test was carried out in a geothermal doublet system to study the injection behavior of a developed reservoir known to be fractured. The doublet produces about 320 gpm of 160 degrees Fahrenheit water that is used for space heating and then injected; the wells are spaced 250 ft apart. Tracer breakthrough was observed in 2 hours and 45 minutes in the production well, indicating fracture flow. However, the tracer concentrations were low and indicated porous media flow; the tracers mixed with a reservoir volume much larger than a fracture.

  20. Doublet Tracer Testing in Klamath Falls, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Gudmundsson, J.S.; Johnson, S.E.; Horne, R.N.; Jackson, P. B. [Pet. Eng. Dept., Stanford University; Culver, G.G. [Geo-Heat Center, Oregon Institute of Technology, Klamath Falls, OR

    0001-01-01

    A tracer test was carried out in a geothermal doublet system to study the injection behavior of a developed reservoir known to be fractured. The doublet produces about 320 gpm of 160 degrees Fahrenheit water that is used for space heating and then injected; the wells are spaced 250 ft apart. Tracer breakthrough was observed in 2 hours and 45 minutes in the production well, indicating fracture flow. However, the tracer concentrations were low and indicated porous media flow; the tracers mixed with a reservoir volume much larger than a fracture.

  1. Assessment of chest pain in hypertrophic cardiomyopathy using exercise thallium-201 myocardial scintigraphy

    International Nuclear Information System (INIS)

    Pitcher, D.; Wainwright, R.; Maisey, M.; Curry, P.; Sowton, E.

    1980-01-01

    Exercise thallium-201 myocardial scintigraphy was performed in 23 patients with hypertrophic cardiomyopathy. Eighteen patients presented with chest pain which was a persistent symptom in 11. Selective coronary arteriography was performed in 16 patients and showed normal coronary arteries in 15 and insignificant luminal irregularities in one patient. Eighteen patients had abnormal scintigrams. Three had an abnormal distribution of tracer entirely attributable to asymmetric septal hypertrophy, whereas 15 had discrete tracer uptake defects which could not be explained solely by myocardial hypertrophy. In this latter group of patients three scintigraphic patterns were identified: (1) in 10 patients defects were seen in scintigrams immediately after exercise but not in delayed images obtained four to six hours later. Eight of these patients had chest pain. (2) Four patients had uptake defects seen in both initial and delayed images. One patient had chest pain. (3) In three patients, one of whom had chest pain, tracer defects were seen only in delayed images and were not apparent in the initial scintigrams. Chest pain occurred in eight out of 10 patients with scintigraphic evidence of myocardial ischaemia but was present in only three out of 13 patients with non-ischaemic scintigrams. The value of exercise thallium-201 myocardial imaging as a diagnostic technique in hypertrophic cardiomyopathy appears limited. Scintigraphic evidence of regional myocardial ischaemia in the absence of significant coronary artery disease, however, contributes to an understanding of the mechanism of angina production in patients with hypertrophic cardiomyopathy. (author)

  2. Quantitative Myocardial Perfusion with Dynamic Contrast-Enhanced Imaging in MRI and CT: Theoretical Models and Current Implementation

    Directory of Open Access Journals (Sweden)

    G. J. Pelgrim

    2016-01-01

    Full Text Available Technological advances in magnetic resonance imaging (MRI and computed tomography (CT, including higher spatial and temporal resolution, have made the prospect of performing absolute myocardial perfusion quantification possible, previously only achievable with positron emission tomography (PET. This could facilitate integration of myocardial perfusion biomarkers into the current workup for coronary artery disease (CAD, as MRI and CT systems are more widely available than PET scanners. Cardiac PET scanning remains expensive and is restricted by the requirement of a nearby cyclotron. Clinical evidence is needed to demonstrate that MRI and CT have similar accuracy for myocardial perfusion quantification as PET. However, lack of standardization of acquisition protocols and tracer kinetic model selection complicates comparison between different studies and modalities. The aim of this overview is to provide insight into the different tracer kinetic models for quantitative myocardial perfusion analysis and to address typical implementation issues in MRI and CT. We compare different models based on their theoretical derivations and present the respective consequences for MRI and CT acquisition parameters, highlighting the interplay between tracer kinetic modeling and acquisition settings.

  3. Nanoparticle tracers in calcium carbonate porous media

    KAUST Repository

    Li, Yan Vivian; Cathles, Lawrence M.; Archer, Lynden A.

    2014-01-01

    the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles

  4. Investigation of Groundwater Flow Variations near a Recharge Pond with Repeat Deliberate Tracer Experiments

    Directory of Open Access Journals (Sweden)

    Jordan F Clark

    2014-06-01

    Full Text Available Determining hydraulic connections and travel times between recharge facilities and production wells has become increasingly important for permitting and operating managed aquifer recharge (MAR sites, a water supply strategy that transfers surface water into aquifers for storage and later extraction. This knowledge is critical for examining water quality changes and assessing the potential for future contamination. Deliberate tracer experiments are the best method for determining travel times and identifying preferential flow paths between recharge sites over the time scales of weeks to a few years. This paper compares the results of two deliberate tracer experiments at Kraemer Basin, Orange County, CA, USA. Results from the first experiment, which was conducted in October 1998, showed that a region of highly transmissive sedimentary material extends down gradient from the basin for more than 3 km [1]. Mean groundwater velocities were determined to be approximately 2 km/year in this region based on the arrival time of the tracer center of mass. A second experiment was initiated in January 2008 to determine if travel times from this basin to monitoring and production wells changed during the past decade in response to new recharge conditions. Results indicate that flow near Kraemer Basin was stable, and travel times to most wells determined during both experiments agree within the experimental uncertainty.

  5. Unexpected myocardial uptake on bone scintigraphy in an infant with Kawasaki disease

    International Nuclear Information System (INIS)

    Macdonald, W.B.G.; Troedson, R.G.

    2003-01-01

    Full text: A two-month-old female infant was admitted to hospital because of irritability and poor feeding over the preceding two weeks. There was no history of fever but serum inflammatory markers were elevated and a throat swab yielded a pure growth of Strep, pyogenes. There was no response to antibiotics. The nursing staff noted the infant disliked handling and skeletal pathology was suspected. A bone scan using Tc-99m hydroxymethylene diphosphonate (HDP) showed myocardial activity, with no evidence of abnormal skeletal activity. Subsequent echocardiography showed coronary artery ectasia, typical of Kawasaki disease, with papillary muscle dysfunction, indicating likely myocarditis. A diagnosis of myocarditis secondary to Kawasaki disease was made and the patient promptly improved following intravenous immunoglobulin therapy. Cardiac manifestations of Kawasaki disease included coronary artery aneurysms, myocardial infarction, regional perfusion abnormalities and myocarditis. Myocardial uptake of phosphate tracers is well known following myocardial infarction but there was no wall motion disturbance or ECG abnormality to suggest infarction in this patient and she was felt to have myocarditis. Myocardial uptake of phosphate tracers has not previously been reported in Kawasaki disease. Copyright (2003) The Australian and New Zealand Society of Nuclear Medicine Inc

  6. Using the dye tracer for visualization of preferential flow in macro and micro-scale

    Czech Academy of Sciences Publication Activity Database

    Kodešová, R.; Němeček, K.; Kodeš, V.; Fér, M.; Jirků, V.; Nikodem, A.; Žigová, Anna; Jakšík, O.; Kočárek, M.

    2010-01-01

    Roč. 12, - (2010) ISSN 1029-7006. [European Geosciences Union General Assembly 2010. 02.05.2010-07.05.2010, Wienna] R&D Projects: GA ČR GA526/08/0434 Institutional research plan: CEZ:AV0Z30130516 Keywords : dye tracer * preferential flow * micromorphology Subject RIV: DF - Soil Science

  7. Determination of Columbia River flow times from Pasco, Washington using radioactive tracers introduced by the Hanford reactors

    Science.gov (United States)

    Nelson, Jack L.; Perkins, R.W.; Haushild, W.L.

    1966-01-01

    Radioactive tracers introduced into the Columbia River in cooling water from the Hanford reactors were used to measure flow times downstream from Pasco, Washington, as far as Astoria, Oregon. The use of two tracer methods was investigated. One method used the decay of a steady release of Na24 (15-hour half-life) to determine flow times to various downstream locations, and flow times were also determined from the time required for peak concentration of instantaneous releases of I131 (8-day half-life) to reach these locations. Flow times determined from the simultaneous use of the two methods agreed closely. The measured flow times for the 224 miles from Pasco to Vancouver, Washington, ranged from 14.6 to 3.6 days, respectively, for discharges of 108,000 and 630,000 ft3/sec at Vancouver, Washington. A graphic relation for estimating flow times at discharges other than those measured and for several locations between Pasco and Vancouver was prepared from the data of tests made at four river discharges. Some limited data are also presented on the characteristics of dispersion of I131 in the Columbia River.

  8. Suitability of tracers; Eignung von Tracern

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, D. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany). Inst. fuer Hydrologie

    1999-02-01

    Hydrological tracer techniques are a means of making statements on the direction and speed of underground water. One of the simpler tasks is to find out whether there is hydrological communication between two given points. This requires a determination of the direction of flow, which places less exacting demands on the properties of the tracer than does the task of determining the flow velocity of underground water. Tracer methods can serve to infer from flow velocity the distance (flow) velocity, which is defined as the ratio between the distance between two points located in flow direction and the actual time it takes water to flow from one to the other. [Deutsch] Mit Hilfe der hydrologischen Markierungstechniken koennen Aussagen ueber die Richtung und die Geschwindigkeit von Bewegungen des unterirdischen Wassers gemacht werden. Der einfachere Fall liegt vor, wenn festgestellt werden soll, ob zwischen zwei Punkten eine hydrologische Verbindung besteht. Bei dieser Fliessrichtungsbestimmung sind die Forderungen an die Eigenschaften der einzusetzenden Tracer geringer als bei der Bestimmung der Geschwindigkeit des unterirdischen Wassers. Von den Geschwindigkeiten des unterirdischen Wassers ist die Abstands-(Fliess)geschwindigkeit, die definiert ist durch das Verhaeltnis aus dem Abstand und der wahren Fliesszeit zwischen zwei in Bewegungsrichtung gelegenen Punkten, durch Tracermethoden zu bestimmen. (orig.)

  9. Simulation and interpretation of inter-well tracer tests

    Directory of Open Access Journals (Sweden)

    Dugstad Øyvind

    2013-05-01

    Full Text Available In inter-well tracer tests (IWTT, chemical compounds or radioactive isotopes are used to label injection water and gas to establish well connections and fluid patterns in petroleum reservoirs. Tracer simulation is an invaluable tool to ease the interpretation of IWTT results and is also required for assisted history matching application of tracer data. In this paper we present a new simulation technique to analyse and interpret tracer results. Laboratory results are used to establish and test formulations of the tracer conservation equations, and the technique is used to provide simulated tracer responses that are compared with observed tracer data from an extensive tracer program. The implemented tracer simulation methodology use a fast post-processing of previously simulated reservoir simulation runs. This provides a fast, flexible and powerful method for analysing gas tracer behaviour in reservoirs. We show that simulation time for tracers can be reduced by factor 100 compared to solving the tracer flow equations simultaneously with the reservoir fluid flow equations. The post-processing technique, combined with a flexible built-in local tracer-grid refinement is exploited to reduce numerical smearing, particularly severe for narrow tracer pulses.

  10. Myocardial turnover of P-123I-phenylpentadecanoic acid (I-PPA) in patients with valvular heart and coronary artery disease

    International Nuclear Information System (INIS)

    Reske, S.N.; Biersack, H.J.; Knopp, R.; Winkler, C.; Aurich, D.; Simon, H.; Koischwitz, D.

    1982-01-01

    Myocardial p-I 123 -Phenylpentadecanoic acid (I-PPA) turnover has been evaluated in patients with coronary artery (CAD) and valvular heart disease (VHD) and normal coronaries. After intracoronary I-PPA application myocardial extraction fractions of 25 - 30% of applied radioactivity were observed in patients with VHD, compared to 8 - 35% in patients with CAD. 2 - 3 component myocardial radioactivity clearance with half times of 0.24 - 0.5, 6 - 10 and 40 - 60 min were observed in patients with VHD. Patients with CAD showed monoexponential myocardial radioactivity clearance with half times of 26 - 67 min. After peripheral i.v. tracer application myocardial segments supplied by coronary arteries with 80 - 100% stenosis showed clearly reduced tracer uptake and prolonged elimination half times. Combined evaluation of I-PPA uptake and turnover clearly separated normally perfused myocardial segments from those supplied by coronary arteries with 80 - 100% stenosis. (Author)

  11. Validation of 99mTc-labeled '4+1' fatty acids for myocardial metabolism and flow imaging

    International Nuclear Information System (INIS)

    Mirtschink, Peter; Stehr, Sebastian N.; Walther, Martin; Pietzsch, Jens; Bergmann, Ralf; Pietzsch, Hans-Juergen; Weichsel, Johannes; Pexa, Annette; Dieterich, Peter; Wunderlich, Gerd; Binas, Bert; Kropp, Joachim; Deussen, Andreas

    2009-01-01

    Introduction: 13 C, 18 F and 123 I fatty acids (FA) are used for myocardial imaging. Recently, our group showed that [ 99m Tc]-labeled '4+1' FA are extracted into the rat and guinea pig myocardium. The present study evaluates determinants of myocardial uptake and whole body biodistribution of these FA derivatives. Methods: Studies were performed with isolated perfused hearts of Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) with a FAT/CD36 deficiency, as well as with heart type FA binding protein knockout mice (H-FABP) -/- and H-FABP +/+ . Eight 4+1- 99m Tc-FA were applied for 3 min followed by 1-min washout. A mathematical model was used to analyze FA dynamics and binding to proteins. Whole-body distribution was studied in rats with and without Tween 80. In vitro fractionation studies with [ 99m Tc]-FA assessed red blood cell uptake as well as association with plasma lipoproteins very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Results: Myocardial extraction was 19.0-33.0% of the infused dose in isolated WKY and 15.2-26.4% in SHR hearts. However, H-FABP -/- showed a marked reduction of tracer extraction [2.8±0.6%ID (percent injected dose) vs. 17±2%ID P 99m Tc-FA with albumin reduced ventricular extraction (P 99m Tc]-FA 4+1 derivatives is dependent on H-FABP. These substances may therefore provide a new tool to specifically assess regional myocardial changes of H-FABP.

  12. Assessment of regional myocardial blood flow with N-13 ammonia PET

    International Nuclear Information System (INIS)

    Himi, Toshiharu

    1992-01-01

    Regional myocardial blood flow (RMBF) has been assessed with O-15 water, O-15 CO 2 and N-13 ammonia in Japan, and O-15 water has been used most commonly for quantitative measurement of RMBF with Iida's method. Though myocardial image quality with N-13 ammonia is superior to that with O-15 water or that with O-15 CO 2 , RMBF was not assessed quantitatively with N-13 ammonia. We have attempted to assess RMBF non-invasively with N-13 ammonia and dynamic PET. Yoshida et. al applied the first-pass flow model to N-13 ammonia dynamic PET for measurement of RMBF. We could measure RMBF of the patients with hypertrophic cardiomyopathy (HCM) and could assess effects of vaso-dilating agents on RMBF non-invasively with this method. But this method dose not take account of cross-contamination of recorded counts between myocardium and surrounding tissues, and hence we have applied factor analysis to dynamic PET for correction of that. It was suggested that cross-contamination in normal cases could be corrected by the factor analysis and there were few cross-contamination in the patients with HCM. (author)

  13. 3-D migration experiment - report 2: Instrumentation and tracers

    International Nuclear Information System (INIS)

    Abelin, H.; Birgersson, L.; Gidlund, J.

    1987-11-01

    This report is one of the four reports describing the Stripa 3D experiment where water and tracer flow has been monitored in a specially excavated drift in the Stripa mine. The experiment was performed in a specially excavated drift at the 360 m level in granite. The whole ceiling and upper part of the walls were covered with more than 350 individual plastic sheets where the water flow into the drift could be collected. 11 different tracers were injected at distances between 11 and 50 m from the ceiling of the drift. The flow rate and tracer monitoring was kept up for more than two years. The tracer breakthrough curves and flow rate distributions were used to study the flow paths, velocities, hydraulic conductivities, dispersivities and channeling effects in the rock. The report describes the instrumentation developed and used as well as the tracers that were tested and used in the experiment. (orig.)

  14. Enhanced Oil Recovery: Aqueous Flow Tracer Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Rovani; John Schabron

    2009-02-01

    A low detection limit analytical method was developed to measure a suite of benzoic acid and fluorinated benzoic acid compounds intended for use as tracers for enhanced oil recovery operations. Although the new high performance liquid chromatography separation successfully measured the tracers in an aqueous matrix at low part per billion levels, the low detection limits could not be achieved in oil field water due to interference problems with the hydrocarbon-saturated water using the system's UV detector. Commercial instrument vendors were contacted in an effort to determine if mass spectrometry could be used as an alternate detection technique. The results of their work demonstrate that low part per billion analysis of the tracer compounds in oil field water could be achieved using ultra performance liquid chromatography mass spectrometry.

  15. The constant rate injection tracer method - principle and application of a useful system for the investigation of single- and two-phase flows in thermal power plants

    International Nuclear Information System (INIS)

    Ederhof, A.; Lindberg, G.

    1985-01-01

    The ''tracer technique'', developed by Brown, Boveri and Company, permits measurement of water (liquid) mass flows, as part of the requested steam wetness, in steam turbine cycles. The additionally required steam mass flows can be calculated from mass flow balances (e.g. after condensation in a heater and subsequent measuring of the condensate flow) or energy balances. This measuring method is basically a dilution measurement using a radioactive or inactive tracer. If the radionuclide 24 Na is used, the measuring uncertainties will be typically 0.5-1.0%. The tracer technique was developed for largely automated parallel measurements on up to 30 lines of large capacity steam turbines. The example of the Ringhals 3 nuclear power plant illustrates that the tracer measuring method, applied during an acceptance test, yields better information on the functioning of the turbine cycle. (orig./GL) [de

  16. Environmental Tracers

    Directory of Open Access Journals (Sweden)

    Trevor Elliot

    2014-10-01

    Full Text Available Environmental tracers continue to provide an important tool for understanding the source, flow and mixing dynamics of water resource systems through their imprint on the system or their sensitivity to alteration within it. However, 60 years or so after the first isotopic tracer studies were applied to hydrology, the use of isotopes and other environmental tracers are still not routinely necessarily applied in hydrogeological and water resources investigations where appropriate. There is therefore a continuing need to promote their use for developing sustainable management policies for the protection of water resources and the aquatic environment. This Special Issue focuses on the robustness or fitness-for-purpose of the application and use of environmental tracers in addressing problems and opportunities scientifically, to promote their wider use and to address substantive issues of vulnerability, sustainability, and uncertainty in (groundwater resources systems and their management.

  17. Role of myocardial perfusion single photon emission computed tomography in pediatric cardiology practice

    Directory of Open Access Journals (Sweden)

    Sundaram P

    2009-01-01

    Full Text Available Diagnostic and prognostic power of myocardial perfusion imaging in patients with coronary artery disease has been demonstrated with planar imaging which was further improvised with addition of gated SPECT and newer Technetium labeled myocardial perfusion tracers like SestaMIBI, Tetrofosmin. Myocardial perfusion abnormalities at rest and after stress are considered to be the best predictors of cardiac event-free survival in adults with ischemic heart disease. This article highlights various myocardial perfusion imaging (MPIradiopharmaceuticals, exercise procedures, pharmacological stress protocols, indications for MPI and myocardial perfusion patterns in children with some of the common congenital and acquired heart diseases.

  18. Generator-produced rubidium-82 positron emission tomography myocardial perfusion imaging. From basic aspects to clinical applications

    International Nuclear Information System (INIS)

    Yoshinaga, Keiichiro; Klein, R.; Tamaki, Nagara

    2010-01-01

    Cardiovascular disease is the leading cause of death in modern industrialized countries with an aging population. This fact has fueled the need for innovative diagnostic testing intended to improve coronary artery disease (CAD) patient care. Detection of myocardial ischemia using myocardial perfusion imaging (MPI) plays an important role for CAD diagnosis and the prediction of future risk of cardiovascular events. Positron emission tomography (PET) MPI has high diagnostic accuracy and can estimate regional myocardial blood flow (MBF) in patients with CAD. Rubidium-82 ( 82 Rb) is a generator-produced PET myocardial perfusion tracer and has been widely used in North America in clinical practice. 82 Rb PET has recently become available in some cardiovascular centers in Europe and Japan. Clinical trials are expected in both regions. 82 Rb PET has high diagnostic accuracy and recent data have shown its prognostic value. Thus, 82 Rb PET would greatly contribute to CAD patients' care. 82 Rb PET can also be used to quantify MBF. This review describes the current status of 82 Rb MPI from basic principles to clinical implications. This paper also highlights the recent development of MBF quantification using 82 Rb PET. (author)

  19. Comparison between the summed difference score and myocardial blood flow measured by 13N-ammonia.

    Science.gov (United States)

    Giubbini, Raffaele; Peli, Alessia; Milan, Elisa; Sciagrà, Roberto; Camoni, Luca; Albano, Domenico; Bertoli, Mattia; Bonacina, Mattia; Motta, Federica; Statuto, Massimo; Rodella, Carlo Alberto; De Agostini, Antonio; Calabretta, Raffaella; Bertagna, Francesco

    2017-02-03

    Both the myocardial perfusion pattern and myocardial blood flow (MBF) are used to assess patients with suspected coronary artery disease (CAD). The aim of this study was to compare the perfusion pattern (using the summed difference score [SDS]) to MBF in a consecutive group of patients undergoing PET/CT with 13 N-ammonia ( 13 NH 3 ). 47 consecutive patients, aged 65 ± 12 years (42 men) with known or suspected CAD, underwent vasodilator stress/rest PET/CT with 13 NH 3 for clinical indications. The SDS was determined by a commercially available software based on a 17-segment model. MBF was measured at rest and during hyperemia by dynamic acquisition and single-compartment model analysis. From the rest and stress MBF, the absolute difference (stress-rest) in myocardial blood flow defined as difference in myocardial blood flow (DMBF) was derived. There were no significant differences between patients with no ischemia (SDS ≤ 1) and those with ischemia (SDS > 1) in CFR (2.84 ± 0.73 vs 2.63 ± 0.89, P = NS) and DMBF (1.34 ± 0.45 vs 1.24 ± 0.53 mL·minute -1 ·g -1 , P = NS). There were however significant regional differences (141 different vascular territories in 47 patients) between these two groups (CFR: 2.84 ± 0.95 vs 2.16 ± 0.57, P measurements (stress-rest) and it correlates better with regional DMBF, which is another measurement that reflects the difference between stress and rest. The correlation is better on regional than global basis.

  20. Dual myocardial scintigraphic imaging using {sup 123}I-BMIPP and {sup 201}Tl in patients with Duchenne`s progressive muscular dystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Akira [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    1996-03-01

    Dual single photon emission computed tomography (SPECT) was performed in 30 patients with Duchenne`s muscular dystrophy (DMD) using {sup 201} thallium (Tl) for myocardial perfusion {sup 123}I-{beta}-methyl-p-iodophenylpentadecanoic acid (BMIPP) for myocardial fatty acid metabolism scintigraphy. The left ventricle was divided into 9 regions, and accumulation of the radiotracers was assessed visually for each region to calculate defect score for each tracer. There was some degree of decrease in the myocardial accumulation of both tracers in all DMD patients. Reduced accumulation was most common at the apex (BMIPP, 70%; Tl, 63%), followed by the posterior wall, lateral wall, and anterior wall. It was less common on the apical side of the ventricular septum for both tracers (BMIPP, 3%; Tl, 17%). Accumulation of Tl was lower than BMIPP in 18/30 patients (60%) and higher in 9 (30%), while both tracers showed equal accumulation in 3 (10%). BMIPP showed higher accumulation than Tl in all regions but the septum. A significant negative correlation was found between the defect scores for both tracers and the left ventricular ejection fraction (LVEF) (r=-0.629 for Tl; r=-0.567 for BMIPP). The strongest negative correlation was that between the sum of the Tl and BMIPP defect scores and the LVEF (r=-0.681). Dual SPECT myocardial scintigraphy with Tl and BMIPP provided an accurate evaluation of the progression of cardiac lesions in DMD by detecting abnormalities of the myocardial metabolism of each substance thereby enabling the assessment of left ventricular function. (author).

  1. Measurement and simulation of the turbulent dispersion of a radioactive tracer in a two-phase flow system

    Energy Technology Data Exchange (ETDEWEB)

    Hensel, F; Rohde, U

    1998-10-01

    The turbulent dispersion of a radiotracer in an experimental setup with a natural convection liquid-gaseous flow was investigated. A liquid-gaseous bubbly flow was generated in a narrow tank by injection of pressurized air into water or by catalytic disintegration of H{sub 2}O{sub 2}. Turbulent Prandtl numbers for gas and tracer dispersion were varied. In the case of higher gas superficial velocities (J{sub gas}{approx}5-15 mm/s), a reasonable agreement was achieved between calculated and measured tracer transport velocity and dispersion coefficient values. A nearly linear correlation between j{sub gas} and D was found in agreement with other authors. The calculation results contribute to a better understanding of the phenomena and interpretation of the measurement results as well as to the validation of the CFD code for turbulent two-phase flow applications. Further investigations are necessary to improve the agreement in the cases of H{sub 2}O{sub 2} disintegration and low gas superficial velocities. (orig.)

  2. Measurement and simulation of the turbulent dispersion of a radioactive tracer in a two-phase flow system

    International Nuclear Information System (INIS)

    Hensel, F.; Rohde, U.

    1998-01-01

    The turbulent dispersion of a radiotracer in an experimental setup with a natural convection liquid-gaseous flow was investigated. A liquid-gaseous bubbly flow was generated in a narrow tank by injection of pressurized air into water or by catalytic disintegration of H 2 O 2 . Turbulent Prandtl numbers for gas and tracer dispersion were varied. In the case of higher gas superficial velocities (J gas ∼5-15 mm/s), a reasonable agreement was achieved between calculated and measured tracer transport velocity and dispersion coefficient values. A nearly linear correlation between j gas and D was found in agreement with other authors. The calculation results contribute to a better understanding of the phenomena and interpretation of the measurement results as well as to the validation of the CFD code for turbulent two-phase flow applications. Further investigations are necessary to improve the agreement in the cases of H 2 O 2 disintegration and low gas superficial velocities. (orig.)

  3. Field and Laboratory Tests of Chromium-51-EDTA and Tritium Water as a Double Tracer for Groundwater Flow

    International Nuclear Information System (INIS)

    Knutsson, G.; Uunggren, K.; Forsberg, H. G.

    1963-01-01

    Since 1958 field experiments and laboratory tests have been made in a study of groundwater flow in different geological and mineralogical environments by the use of gamma-emitting tracers ana tritium water. The velocity of groundwater flow in soil is rather low, and tracers with medium or long half-life must be chosen to trace the movement. A stable EDTA-complex of Cr 51 (half-life 28 d) was developed for this purpose and used together with tritium water. With this double tracer it was possible to follow the groundwater flow by measurement of the gamma radiation from Cr 51 directly in the field and thereby to reduce the number of water samples for precise laboratory assessment. By comparison of the measured activities of Cr 51 and tritium it was possible to determine whether there was any retardation or loss of the chromium complex as a result of adsorption. Six field investigations, each of about two months' duration, have been made in glacifluvial sand and gravel. The results from these show that the chromium complex is transported as rapidly as the tritium water is, even at low concentrations (0. 01 ppm) of the complex. 17 field investigations of one to three months' duration with this double tracer have been carried out in various till (moraine) soils for a study of certain hydrological problems. Laboratory tests with soil and water from the various areas of field investigations have shown that the chromium complex does not hydrolyse at concentrations above 0.01 ppm. Further laboratory tests of the reliability of the chromium complex in different mineralogical environments are in progress. A number of investigations of groundwater flow through fissures and channels have abo been made. When the velocity of flow was assumed to be very high, Br 82 as bromide ion or Rhodamine-B, a fluorescent organic dye, were used. EDTA-Cr 51 and tritium water were, however, used when the velocity was considered low or when, as in karst, a great number of channels or large

  4. Tracer transport in fractured rocks

    International Nuclear Information System (INIS)

    Tsang, C.F.; Tsang, Y.W.; Hale, F.V.

    1988-07-01

    Recent interest in the safety of toxic waste underground disposal and nuclear waste geologic repositories has motivated many studies of tracer transport in fractured media. Fractures occur in most geologic formations and introduce a high degree of heterogeneity. Within each fracture, the aperture is not constant in value but strongly varying. Thus for such media, tracer tends to flow through preferred flowpaths or channels within the fractures. Along each of these channels, the aperture is also strongly varying. A detailed analysis is carried out on a 2D single fracture with variable apertures and the flow through channels is demonstrated. The channels defined this way are not rigidly set pathways for tracer transport, but are the preferred flow paths in the sense of stream-tubes in the potential theory. It is shown that such variable-aperture channels can be characterized by an aperture probability distribution function, and not by the exact deterministic geometric locations. We also demonstrate that the 2D tracer transport in a fracture can be calculated by a model of a system of 1D channels characterized by this distribution function only. Due to the channeling character of tracer transport in fractured rock, random point measurements of tracer breakthrough curves may give results with a wide spread in value due to statistical fluctuations. The present paper suggests that such a wide spread can probably be greatly reduced by making line/areal (or multiple) measurements covering a few spatial correlation lengths. 13 refs., 11 figs., 1 tab

  5. Estimation of myocardial blood flow and myocardial flow reserve by 99mTc-sestamibi imaging: comparison with the results of [15O]H2O PET

    International Nuclear Information System (INIS)

    Ito, Yoshinori; Noriyasu, Kazuyuki; Kohya, Tetsuro; Kitabatake, Akira; Katoh, Chietsugu; Kuge, Yuji; Furuyama, Hideto; Morita, Koichi; Tamaki, Nagara

    2003-01-01

    We developed a noninvasive method to quantitatively estimate the myocardial blood flow (MBF) index and flow reserve (MFR) using dynamic and static data obtained with technetium-99m sestamibi, and compared the results with MBF and MFR measured by oxygen-15-labeled water ([ 15 O]H 2 O) PET. Twenty patients with coronary artery disease (CAD) and nine normal subjects underwent both 99m Tc-sestamibi and PET studies within 2 weeks. From the anterior view, dynamic data were acquired for 2 min immediately after the injection of 99m Tc-sestamibi, and planar static images were also obtained after 5 min at rest and during ATP stress (0.16 mg kg -1 min -1 for 5 min) on another day. The area under the time-activity curve on the aortic arch (Aorta ACU), myocardial weight with the SPET image (M), and the myocardial count on the planar image for 1 min (C m ) were obtained. The MBF index (MBFI) was calculated as follows: MBFI=C m /Aorta ACU x 100/M. MFR was measured by dividing the MBFI at ATP stress by MBFI at rest. The MBFI measured by 99m Tc-sestamibi was significantly correlated with MBF obtained using [ 15 O]H 2 O PET (MBFI=13.174+11.732 x MBF, r=0.821, P 99m Tc-sestamibi was well correlated with that obtained using [ 15 O]H 2 O PET, with some underestimation (r=0.845, P 99m Tc-sestamibi in patients with CAD was significantly lower than that in normal subjects (CAD: 1.484±0.256 vs normal: 2.127±0.308, P 99m Tc-sestamibi. This may be useful for the quantitative assessment of CAD, especially in those patients with diffuse coronary disease. (orig.)

  6. Correlation of myocardial p-(123)I-iodophenylpentadecanoic acid retention with (18)F-FDG accumulation during experimental low-flow ischemia.

    Science.gov (United States)

    Shi, Cindy Q; Young, Lawrence H; Daher, Edouard; DiBella, Edward V R; Liu, Yi-Hwa; Heller, Eliot N; Zoghbi, Sami; Wackers, Frans J Th; Soufer, Robert; Sinusas, Albert J

    2002-03-01

    Myocardial ischemia is associated with reduced free fatty acid (FFA) beta-oxidation and increased glucose utilization. This study evaluated the potential of dynamic SPECT imaging of a FFA analog, p-(123)I-iodophenylpentadecanoic acid (IPPA), for detection of ischemia and compares retention of IPPA with (18)F-FDG accumulation. In a canine model of regional low-flow ischemia (n = 9), serial IPPA SPECT images (2 min per image) were acquired over 52--90 min. In a subset of dogs (n = 6), (18)F-FDG was injected after completing SPECT imaging and allowed to accumulate for 40 min before killing the animals. Flow was assessed with radiolabeled microspheres. Myocardial metabolism was evaluated independently by selective coronary arterial and venous sampling. Serial IPPA SPECT images showed an initial defect in the ischemic region (0.70% plus minus 0.03% ischemic-to-nonischemic ratio), which normalized within 48 min because of the slower IPPA clearance from the ischemic region (t(1/2) = 54.2 plus minus 3.3 min) relative to the nonischemic region (t(1/2) = 36.7 plus minus 5.6 min) (P < 0.05). Delayed myocardial IPPA and (18)F-FDG activities were correlated (r = 0.70; n = 576 segments), and both were maximally increased in segments with a moderate flow reduction (IPPA, 151% of nonischemic; (18)F-FDG, 450% of nonischemic; P < 0.05). Serial SPECT imaging showed delayed myocardial clearance of IPPA in ischemic regions with moderate flow reduction, which lead to increased late myocardial retention of IPPA. Retention of IPPA correlated with (18)F-FDG accumulation, supporting the potential of IPPA as a noninvasive marker of ischemic myocardium.

  7. Tissue Clearance of {sup 131}I and Total Peripheral Resistance in Myocardial Infarction and Hypertension, and During Angiotensin Infusion

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, F. K.; Bors, K. J.; Long, T. E.; Lestina, J. [University of Southern California School of Medicine, Los Angeles, CA (United States)

    1971-02-15

    Tissue clearance of {sup 131}I from the thigh, cardiac output and peripheral resistance was determined in 25 patients: 13 normotensive with recent myocardial infarction but not in congestive heart failure, 7 with hypertension and 5 normotensive control subjects. The effect of the synthesized pressor agent Angiotensin II on the same three measurements was also studied. The present investigation continues a previous one of ours, where a tracer dose of {sup 131}I was injected into the thigh of patients with recent myocardial infarction without signs of heart failure, and its clearance was found to be longer than that of normal subjects. This was thought to be due to increased peripheral resistance or to reduced perfusion of the capillary bed secondary to lowered cardiac output, With the 25 subjects, injection into the thigh of tracer amounts of radioactive iodine was done by Hypospray, a method with distinct advantages over needle injection. After measuring tissue clearance of the tracer, cardiac output was determined by a method which records the transit of the injected radioactive bolus through the heart. The Angiotensin was administered by intravenous infusion to four of the normotensive and one of the hypertensive patients. Calculations of cardiac output, total peripheral resistance, mean blood pressure and blood volume were made by means of standard formulae. Results of the study confirmed expectations. Those patients with myocardial infarction who had delayed tissue clearance of {sup 131}I also had reduced cardiac output. The patients with hypertension had normal tissue clearance of {sup 131}I and normal cardiac output in the presence of increased peripheral resistance. Equivalent hypertension and increased peripheral resistance induced in normotensive subjects by Angiotensin resulted in lowered cardiac output and delayed tissue clearance of {sup 131}I. An increased sensitivity to Angiotensin was noted in hypertensive patients. The tissue clearance of {sup 131}I

  8. Beta-methyl[1-11C]heptadecanoic acid: a new myocardial metabolic tracer for positron emission tomography

    International Nuclear Information System (INIS)

    Livni, E.; Elmaleh, D.R.; Levy, S.; Brownell, G.L.; Strauss, W.H.

    1982-01-01

    We have tagged heptadecanoic acid with C-11 at the carboxyl group and have inserted a methyl radical in the beta position to inhibit beta oxidation of the fatty acid; we have then explored the tracer's potential as an indicator of myocardial metabolism for use with the positron tomograph. In this preliminary evaluation, biodistribution studies were made in rats and dogs, and imaging of normal and infarcted dogs was performed. At 30 min the tissue distribution studies in rats and dogs showed, respectively. 1.9% and 8.3% uptake in the heart. Sequential images of the canine heart exhibited a remarkable uptake, peaking at 16-18 min and retaining the same level of activity over the one-hour study period. Images of the heart after LAD ligation showed an area of diminished uptake corresponding to the region of infarction. Thus this agent has the basic properties required for potential use in the assessment and quantitation of free fatty-acid metabolism in the heart in a manner similar to the measurement of glucose metabolism in the brain with 2-[ 18 F]fluoro-2-deoxy-D-glucose

  9. Noninvasive quantification of myocardial perfusion heterogeneity by Markovian analysis in SPECT nuclear imaging

    International Nuclear Information System (INIS)

    Pons, G.

    2011-01-01

    Cardiovascular diseases are the leading cause of mortality worldwide, and third of these deaths are caused by coronary artery disease and rupture of vulnerable atherosclerotic plaques. The heterogeneous alteration of the coronary microcirculation is an early phenomenon associated with many cardiovascular risk factors that can strongly predict the subsequent development of coronary artery disease, and lead to the appearance of myocardial perfusion heterogeneity. Nuclear medicine allows the study of myocardial perfusion in clinical routine through scintigraphic scans performed after injection of a radioactive tracer of coronary blood flow. Analysis of scintigraphic perfusion images currently allows the detection of myocardial ischemia, but the ability of the technique to measure the perfusion heterogeneity in apparently normally perfused areas is unknown. The first part of this thesis focuses on a retrospective clinical study to determine the feasibility of myocardial perfusion heterogeneity quantification measured by Thallium-201 single photon emission computed tomography (SPECT) in diabetic patients compared with healthy subjects. The clinical study has demonstrated the ability of routine thallium-201 SPECT imaging to quantify greater myocardial perfusion heterogeneity in diabetic patients compared with normal subjects. The second part of this thesis tests the hypothesis that the myocardial perfusion heterogeneity could be quantified in small animal SPECT imaging by Thallium-201 and/or Technetium-99m-MIBI in an experimental study using two animal models of diabetes, and is correlated with histological changes. The lack of difference in myocardial perfusion heterogeneity between control and diabetic animals suggests that animal models are poorly suited, or that the technology currently available does not seem satisfactory to obtain similar results as the clinical study. (author)

  10. Absolute coronary blood flow measurement and microvascular resistance in ST-elevation myocardial infarction in the acute and subacute phase

    Energy Technology Data Exchange (ETDEWEB)

    Wijnbergen, Inge; Veer, Marcel van ' t [Department of Cardiology, Catharina Hospital, Eindhoven (Netherlands); Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven (Netherlands); Lammers, Jeroen; Ubachs, Joey [Department of Cardiology, Catharina Hospital, Eindhoven (Netherlands); Pijls, Nico H.J., E-mail: nico.pijls@cze.nl [Department of Cardiology, Catharina Hospital, Eindhoven (Netherlands); Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven (Netherlands)

    2016-03-15

    Background/Purpose: In a number of patients with acute myocardial infarction (AMI), myocardial hypoperfusion, known as the no-reflow phenomenon, persists after primary percutaneous intervention (PPCI). The aim of this study was to evaluate the feasibility and safety of a new quantitative method of measuring absolute blood flow and resistance within the perfusion bed of an infarct-related artery. Furthermore, we sought to study no-reflow by correlating these measurements to the index of microvascular resistance (IMR) and the area at risk (AR) as determined by cardiac magnetic resonance imaging (CMR). Methods: Measurements of absolute flow and myocardial resistance were performed in 20 patients with ST-segment elevation myocardial infarction (STEMI), first immediately following PPCI and then again after 3–5 days. These measurements used the technique of thermodilution during a continuous infusion of saline. Flow was expressed in ml/min per gram of tissue within the area at risk. Results: The average time needed for measurement of absolute flow, resistance and IMR was 20 min, and all measurements could be performed without complication. A higher flow supplying the AR correlated with a lower IMR in the acute phase. Absolute flow increased from 3.14 to 3.68 ml/min/g (p = 0.25) and absolute resistance decreased from 1317 to 1099 dyne.sec.cm-5/g (p = 0.40) between the first day and fifth day after STEMI. Conclusions: Measurement of absolute flow and microvascular resistance is safe and feasible in STEMI patients and may allow for a better understanding of microvascular (dys)function in the early phase of AMI. - Highlights: • We measured absolute coronary blood flow and microvascular resistance in STEMI patients in the acute phase and in the subacute phase, using the technique of thermodilution with low grade intracoronary continuous infusion of saline. • These measurements are safe and feasible during PPCI in STEMI patients. • In STEMI patients, absolute flow

  11. Study of flow characteristics in a secondary clarifier by numerical simulation and radioisotope tracer technique

    International Nuclear Information System (INIS)

    Kim, H.S.; Shin, M.S.; Jang, D.S.; Jung, S.H.; Jin, J.H.

    2005-01-01

    Numerical simulation in a 2-D rectangular coordinate and experimental study have been performed to figure out the flow characteristics and concentration distribution of a large-scale rectangular final clarifier in wastewater treatment facility located in Busan, S. Korea. The purpose of numerical calculation is to verify the experimentally measured data by radioisotope tracer technique and further to understand the important physical feature occurring in a large-scale clarifier, in many cases which is not sufficient by the aid of limited number of experimental data. To this end, a comprehensive computer program is basically made by SIMPLE algorithm by Patankar with the special emphasis on the parametric evaluation of the various phenomenological models. Calculation results are successfully evaluated against experimental data obtained by the method of radioisotope tracer. Detailed comparison is made on the calculated residence time distribution (RTD) curves with measurement inside the clarifier as well as the exhaust. Further the calculation results predict well the well-known characteristics of clarifier flow such as the waterfall phenomenon at the front end of the clarifier, the bottom density current in the settling zone and the upward flow in the withdrawal zone. Thus it is believed that the flow calculation program and the data incorporation technique of radioisotope measurement employed in this study show the high possibility as a complementary tool of experiment in this area

  12. Evaluation of nonradioactive, colored microspheres for measurement of regional myocardial blood flow in dogs

    International Nuclear Information System (INIS)

    Hale, S.L.; Alker, K.J.; Kloner, R.A.

    1988-01-01

    Measurement of regional myocardial blood flow (RMBF) is crucial in experimental studies of myocardial ischemia and reperfusion in dogs. The standard measurement technique uses radioactive microspheres; however, not all institutions are able to dispose of radioactive waste and therefore cannot make use of this method. We tested a new, nonradioactive microsphere, labeled with colors instead of nuclides. Simultaneous blood flow measurements with two nuclide-labeled and two colored microspheres were performed after coronary occlusion in dogs. Both techniques show a within-method correlation of r greater than 0.98. Duplicate variability for paired RMBF values in 80 samples was 8.7 +/- 0.1% when computed with radioactive microspheres and 13.2 +/- 1.8% when computed with colored microspheres. There was a good correlation in the measurement of RMBF between the radioactive- and colored-microsphere methods (r = 0.98). The best-fitting linear regression line was expressed by the formula: Colored-microsphere RMBF = 1.11 (radioactive-microsphere RMBF)-0.02. When measured by colored microspheres, RMBF was approximately 8% higher than when computed with radioactive microspheres for blood flow values of 0-2 ml/min/g. When blood flow was increased pharmacologically to levels of 2-7.5 ml/min/g, colored microspheres yielded blood flow values 39% higher than the values computed by radioactive microspheres. We conclude that the nonradioactive, colored-microsphere method correlates with the radioactive technique, but at high flows, it yields values greater than those obtained with radioactive microspheres

  13. Scintigraphic demonstration of acute myocardial infarcts

    International Nuclear Information System (INIS)

    Holman, B.L.; Lesch, M.

    1976-01-01

    The feasibility of acute infarct scintigraphy for the clinical evaluation of patients with known or suspected acute myocardial infarction is established. Further development of this methodologic approach may result in even better agents for the visualization of infarcts. Radiotracers with high affinity for the infarct, rapid blood clearance, and low concentrations in surrounding organs, such as liver and bone, would be more suitable than available radiopharmaceuticals for acute myocardial infarct scintigraphy. Ultimately, labeling these tracers and ultra-short-lived radionuclides will enable rapid sequential imaging to assess changes in the extent of infarction and to determine the efficacy of therapies aimed at limiting infarct size

  14. Simultaneous estimates of regional myocardial blood flow and metabolism by the developing chick heart using [201]thallium and [14C] 2-deoxyglucose autoradiography

    International Nuclear Information System (INIS)

    Kostreva, D.R.; Wood, J.D.

    1990-01-01

    Little is known about regional myocardial blood flow and metabolism in the developing heart. Simultaneous estimates of regional myocardial blood flow and glucose metabolism have been made in the adult rat by Yonekura et al using [ 201 ] Thallium (THAL) and [ 14 C]2-deoxyglucose (DG) autoradiography. Since glucose is the primary cardiac metabolic substrate during development, glucose utilization is also an estimate of myocardial metabolism. Examination and comparison of the THAL and DG autoradiographs revealed that there is an uncoupling of blood flow and metabolism in the developing chick heart. Areas of the heart which had marked glucose utilization did not always have marked blood flow. Regions of the heart which had marked blood flow but very little glucose utilization were the interventricular septum and the apex. One explanation for this disparity is that although blood flow may be established in these regions, normal cardiac function requiring significant substrate utilization may not be fully developed

  15. The use of 123I-labeled heptadecanoic acid (HDA) as metabolitic tracer

    International Nuclear Information System (INIS)

    Dudczak, R.; Kletter, K.; Frischauf, H.; Schmoliner, R.; Losert, U.; Angelberger, P.

    1984-01-01

    The feasibility of using 123 I-heptadecanoic acid (HDA) as a metabolic tracer was studied. Different administration routes of HDA were compared. An intracoronary bolus injection was given to calves (n=3), and an intravenous injection was given to patients (n=4). In addition, we examined the influence of 4-h halothane anesthesia in calves and in patients the impact of an isulin (1.5 IU/kg)+glucose (1.5 g/kg) infusion on the myocardial kinetics of HDA. Data were accumulated with a scintillation probe in calves (t=50 min) and a gamma camera in patients (t=70 min). In calves after an intracoronary bolus injection of HDA the myocardial time-activity curve could be described by two exponentials. The mean elimination half-time of the initial phase (tsub(a) 1/2) was 7.3 min and that of the second phase (tsub(b) 1/2) was 35 min. The ratio of the size of the initial and second component at t 0 was 0.93. Halothane anesthesia prolonged the elimination half-times and reduced the component ratio. The biphasic behavior of the myocardial time-activity curve was maintained in patients after intravenous administration of HDA under basal conditions (inital tsub(a) 1/2=8.4 min). However, during infusion of insulin+glucose the decline in the myocardial activity was prolonged and monoexponential. This data show that insulin glucose, interfering with fatty acid metabolism, influences the myocardial washout of HDA, and thus support it use as a metabolic tracer. (orig.)

  16. Efficacy of coronary artery reconstruction in maintaining myocardial viability. Quntitative determination of local myocardial circulation with 13NH3 myocardial positron emission tomography

    International Nuclear Information System (INIS)

    Kobayashi, Satoshi; Takaba, Toshihiro; Kume, Masato; Kashima, Toshitaka; Michihata, Tetsuro.

    1996-01-01

    Thirty patients (280 areas) whose bypass grafts remained patent after surgical reconstruction of the coronary artery were examined. Before and after reconstruction, local myocardial blood circulation in infarcted regions and post-stenotic regions was measured by 13 NH 3 myocardial positron emission computed tomography (PET) at rest or during physical exercise in order to evaluate the efficacy of coronary artery reconstruction. Before operation, mean blood flow in post-stenotic regions (n=198) was 65±15 ml/min/100 g at rest and 85±23 ml/min/100 g during exercise. After coronary artery bypass grafting (CABG), mean blood flow was increased to 78±21 ml/min/100 g at rest (p, 0.01) and 105±32 ml/min/100 g during exercise (p<0.01). In infarcted regions (n=82), mean blood flow before operation was 51±23 ml/min/100 g at rest and 69±23 ml/min/100 g during exercise. After CABG, it increased to 62±19 ml/min/100 g at rest (p<0.01) and 81±29 ml/min/100 g during exercise (p<0.01). Thus, significant increases in blood flow were observed in both post-stenotic and infarcted regions at rest and physical exercise after operation. The regions of infarction were divided into three groups based on local myocardial blood flow at rest before operation: Group I: greater than 45 ml/min/100 g (n=35); Group II: less than 45 ml/min/100 g (n=30) but greater than 30 ml/min/100 g; and Group III: less than 30 ml/min/100 g (n=30). The efficacy of reconstruction was compared among these groups. The group with preoperative myocardial blood flow greater than 30 ml/min/100 g had increased blood flow after operation, indicating myocardial viability. (author)

  17. Correlation between semiquantitative myocardial perfusion score and absolute myocardial flow in 13N-ammonia PET

    International Nuclear Information System (INIS)

    Lee, Byeong Il; Kim, Jung Young; Min, Jung Joon; Song, Ho Chun; Bom, Hee Seung; Kim, Kye Hun; Kim, Su Jin; Lee, Jae Sung

    2007-01-01

    13 N-ammonia is a well known radiopharmaceutical for the measurement of a myocardial blood flow (MBF) non-invasively using PET-CT. In this study, we investigated a correlation between MBF obtained from dynamic imaging and myocardial perfusion score (MPS) obtained from static imaging for usefulness of cardiac PET study. Twelve patients (11 males, 1 female, 57.9 ± 8.6 years old) with suspicious coronary artery disease underwent PET-CT scan. Dynamic scans (6 min: 5 sec X 12, 10 sec X 6, 20 sec X 3, and 30 sec X 6) were initiated simultaneously with bolus injection of 11 MBq/kg 13 N-ammonia to acquire rest and stress image. Gating image was acquired during 13 minutes continuously. Nine-segment model (4 basal walls, 4 mid walls, and apex) was used for a measurement of MBF. Time activity curve of input function and myocardium was extracted from ROI methods in 9 regions for quantification. The MPS were evaluated using quantitative analysis software. To compare between 20-segment model and 9-segment model, 6 basal segments were excluded and averaged segmental scores were used. There are weak correlation between MBF (rest, 0.18-2.38 ml/min/g; stress, 0.40-4.95 ml/min/g) and MPS (rest 22-91%, stress, 14-90%), however the correlation coefficient between corrected MBF and MPS in rest state was higher than stress state (rest r=0.59; stress r=0.80). As a thickening increased, correlation between MBF and MPS also showed good correlation at each segments. Corrected and translated MPS as its characteristics using 13 N-ammonia showed good correlation with absolute MBF measured by dynamic image in this study. Therefore, we showed MPS is one of good indices which reflect MBF. We anticipate PET-CT could be used as useful tool for evaluation of myocardial function in nuclear cardiac study

  18. Regional myocardial blood flow distribution during intracoronary infusion of parathyroid hormone

    International Nuclear Information System (INIS)

    Crass, M.F. III; Lust, R.M.

    1986-01-01

    Although low doses of the biologically-active fragment of parathyroid hormone PTH-(1-34), have been shown to produce potent dilation of the coronary circulation specific regional and transmural (endo/epi) myocardial blood flow (MBF) responses to the hormone have not been described. Anesthetized open-chest mongrel dogs were instrumented to quantitate coronary blood flow and other cardiodynamic parameters. PTH-(1-34) was infused into the left circumflex artery (.008 nmol kg -1 min -1 ). Using the reference withdrawal method, radionuclide-labeled microspheres were injected before (basal flow), during (8 min after new steady-state flow), and after (restoration of basal flow) a 20 min infusion of PTH-(1-34). MFB increased from 76 +- 1.9 to 152 +- 3.5 ml min -1 100 g -1 (P < .001) during PTH-(1-34) infusion. No differences in endo/epi flow ratio or regional coronary blood flow within the left ventricle were detected. Thus, in anesthetized dogs, the increase in MBF observed secondary to the PTH-(1-34)-induced decrease in coronary resistance appeared to be uniform transmurally and regionally, and is probably not the result of a shunting or steal phenomenon

  19. Investigations into the myocardial metabolism of 123-I-ω-HDA in patients showing the clinical signs and symptoms of mitral valve prolapse and previously proven to have no coronary heart disease

    International Nuclear Information System (INIS)

    Voth, E.

    1987-01-01

    In 53 patients showing the clinical signs and symptoms of mitral valve prolapse (MVP) where coronary heart disease (CHD) had previously been excluded by angiography the myocardial metabolism of fatty acids was examined at rest using metabolic myocardial scintigraphy (MMS) and 123-I-ω-HDA as tracer substance. The results were correlated with those obtained by other methods of investigation (findings at rest and during exercise from ECG recordings, tests using a flow-guided catheter and radionuclide ventriculography, further from echocardiography as well as myocardial Tl redistribution scintiscanning during exercise). For purposes of reference, MMS was additionally carried out in twelve normal individuals subjected to coronary angiography to exclude both MVP and CHD. The results of this study would appear to suggest that the pathological findings revealed by myocardial Tl scintigraphy in patients showing symptoms of MVP cannot invariably be classified as 'false' but are at least to some extent attributable to impaired myocardial perfusion, vitality or metabolism. (orig./MG) [de

  20. The stream flow rate measurement using tracer techniques at the Kemubu Agricultural Development Authority (KADA), Kelantan

    International Nuclear Information System (INIS)

    Daud Mohammad; Abd Razak Hamzah; Wan Abd Aziz Wan Mohamad; Juhari Yusoff; Wan Zakaria Wan Mohd Tahir

    1985-01-01

    Measuring the flow rate of a water course is one of the basic operations in hydrology, being of general relevance to water problems and of particular importance in the planning of water control schemes. The techniques commonly used in streamflow gauging are either by a current meter of tracer dilution method. This paper describes the latter technique in which radioisotope Tc-99m was used as a tracer in streamflow measurements performed in 1983 in a few selected irrigation canals and pump house under the Kemubu Agriculture Development Authority (KADA), Kelantan. Total count technique and peak-to-peak method were adopted in this study. (author)

  1. Cardiorespiratory fitness modifies the relationship between myocardial function and cerebral blood flow in older adults.

    Science.gov (United States)

    Johnson, Nathan F; Gold, Brian T; Bailey, Alison L; Clasey, Jody L; Hakun, Jonathan G; White, Matthew; Long, Doug E; Powell, David K

    2016-05-01

    A growing body of evidence indicates that cardiorespiratory fitness attenuates some age-related cerebral declines. However, little is known about the role that myocardial function plays in this relationship. Brain regions with high resting metabolic rates, such as the default mode network (DMN), may be especially vulnerable to age-related declines in myocardial functions affecting cerebral blood flow (CBF). This study explored the relationship between a measure of myocardial mechanics, global longitudinal strain (GLS), and CBF to the DMN. In addition, we explored how cardiorespiratory affects this relationship. Participants were 30 older adults between the ages of 59 and 69 (mean age=63.73years, SD=2.8). Results indicated that superior cardiorespiratory fitness and myocardial mechanics were positively associated with DMN CBF. Moreover, results of a mediation analysis revealed that the relationship between GLS and DMN CBF was accounted for by individual differences in fitness. Findings suggest that benefits of healthy heart function to brain function are modified by fitness. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Three-dimensional visualization of myocardial motion and blood flow with cine-MR images

    International Nuclear Information System (INIS)

    Oshiro, Osamu; Matani, Ayumu; Chihara, Kunihiro; Mikami, Taisei; Kitabatake, Akira.

    1997-01-01

    This paper describes a three-dimensional (3D) reconstruction and presentation method to visualize myocardial motion and blood flow in a heart using cine-MR (magnetic resonance) images. Firstly, the region of myocardium and blood were segmented with certain threshold gray values. Secondly, some slices were interpolated linearly to reconstruct a 3D static image. Finally, a 3D dynamic image was presented with displaying the 3D static images sequentially. The experimental results indicate that this method enables to visualize not only normal but also abnormal blood flow in cine-mode. (author)

  3. The use of 123I-labeled heptadecanoic acid (HDA) as metabolic tracer: preliminary report.

    Science.gov (United States)

    Dudczak, R; Kletter, K; Frischauf, H; Losert, U; Angelberger, P; Schmoliner, R

    1984-01-01

    The feasibility of using 123I-heptadecanoic acid (HDA) as a metabolic tracer was studied. Different administration routes of HDA were compared. An intracoronary bolus injection was given to calves (n = 3), and an intravenous injection was given to patients (n = 4). In addition, we examined the influence of 4-h halothane anesthesia in calves and in patients the impact of an insulin (1.5 IU/kg) + glucose (1.5 g/kg) infusion on the myocardial kinetics of HDA. Data were accumulated with a scintillation probe in calves (t = 50 min) and a gamma camera in patients (t = 70 min). In calves after an intracoronary bolus injection of HDA the myocardial time-activity curve could be described by two exponentials. The mean elimination half-time of the initial phase (ta 1/2) was 7.3 min and that of the second phase (tb 1/2) was 35 min. The ratio of the size of the initial and second component at to was 0.93. Halothane anesthesia prolonged the elimination half-times and reduced the component ratio. The biphasic behavior of the myocardial time-activity curve was maintained in patients after intravenous administration of HDA under basal conditions (initial ta 1/2 = 8.4 min). However, during infusion of insulin + glucose the decline in the myocardial activity was prolonged and monoexponential. This data shows that insulin glucose, interfering with fatty acid metabolism, influences the myocardial washout of HDA, and thus support its use as a metabolic tracer.

  4. Development of quantification methods for the myocardial blood flow using ensemble independent component analysis for dynamic H215O PET

    International Nuclear Information System (INIS)

    Lee, Byeong Il; Lee, Jae Sung; Lee, Dong Soo; Kang, Won Jun; Lee, Jong Jin; Kim, Soo Jin; Chung, June Key; Lee, Myung Chul; Choi, Seung Jin

    2004-01-01

    Factor analysis and independent component analysis (lCA) has been used for handling dynamic image sequences. Theoretical advantages of a newly suggested ICA method, ensemble ICA, leaded us to consider applying this method to the analysis of dynamic myocardial H 2 15 O PET data. In this study, we quantified patients, blood flow using the ensemble ICA method. Twenty subjects underwent H 2 15 O PET scans using ECAT EXACT 47 scanner and myocardial perfusion SPECT using Vertex scanner. After transmission scanning, dynamic emission scans were initiated simultaneously with the injection of 555∼740 MBq H 2 15 O. Hidden independent components can be extracted from the observed mixed data (PET image) by means of ICA algorithms. Ensemble learning is a variational Bayesian method that provides an analytical approximation to the parameter posterior using a tractable distribution. Variational approximation forms a lower bound on the ensemble likelihood and the maximization of the lower bound is achieved through minimizing the Kullback-Leibler divergence between the true posterior and the variational posterior. In this study, posterior pdf was approximated by a rectified Gaussian distribution to incorporate non-negativity constraint, which is suitable to dynamic images in nuclear medicine. Blood flow was measured in 9 regions - apex, four areas in mid wall, and four areas in base wall. Myocardial perfusion SPECT score and angiography results were compared with the regional blood flow. Major cardiac components were separated successfully by the ensemble ICA method and blood flow could be estimated in 15 among 20 patients. Mean myocardial blood flow was 1.2±0.40 ml/min/g in rest, 1.85±1.12 ml/min/g in stress state. Blood flow values obtained by an operator in two different occasion were highly correlated (r=0.99). In myocardium component image, the image contrast between left ventricle and myocardium was 1:2.7 in average. Perfusion reserve was significantly different between

  5. Tritium and deuterium as water tracers in hydrologic systems. Completion report

    International Nuclear Information System (INIS)

    Stewart, G.L.; Stetson, J.R.

    1975-05-01

    A study was conducted to evaluate the suitability of deuterium and tritium as tracers to depict water and pollutant movement in porous media. This involved studying the interaction of these tracers with soil materials and evaluating this interaction in terms of retardation in tracer flow velocity, compared to bulk water flow. Previous work had suggested that tritium and deuterium interact with soils and are removed from tracer solution during flow. The data presented clearly show that a tracing front becomes diluted in tracer during infiltration into oven-dried soil. There appears to be very little difference between the degree of tritium and deuterium interaction. The source of interaction is demonstrated to be primarily hydroxyl associated with the clay minerals. These exchange sites are destroyed by heating soil to 70C which eliminates tracer loss during infiltration

  6. Effect of {beta}{sub 1} adrenergic receptor blockade on myocardial blood flow and vasodilatory capacity

    Energy Technology Data Exchange (ETDEWEB)

    Boettcher, M.; Czernin, J.; Sun, K. [Univ. of California, Los Angeles, CA (United States)] [and others

    1997-03-01

    The {beta}{sub 1} receptor blockade reduces cardiac work and may thereby lower myocardial blood flow (MBF) at rest. The effect of {beta}{sub 1} receptor blockade on hyperemic MBF is unknown. To evaluate the effect of selective {beta}{sub 1} receptor blockade on MBF at rest and during dipyridamole induced hyperemia, 10 healthy volunteers (8 men, 2 women, mean age 24 {+-} 5 yr) were studied using {sup 13}N-ammonia PET (two-compartment model) under control conditions and again during metoprolol (50 mg orally 12 hr and 1 hr before the study). The resting rate pressure product (6628 {+-} 504 versus 5225 {+-} 807) and heart rate (63 {+-} 6-54 {plus_minus} 5 bpm) declined during metoprolol (p < 0.05). Similarly, heart rate and rate pressure product declined from the baseline dipyridamole study to dipyridamole plus metoprolol (p < 0.05). Resting MBF declined in proportion to cardiac work by approximately 20% from 0.61 {+-} 0.09-0.51 {+-} 0.10 ml/g/min (p < 0.05). In contrast, hyperemic MBF increased when metoprolol was added to dipyridamole (1.86 {plus_minus} 0.27 {+-} 0.45 ml/g/min; p<0.05). The decrease in resting MBF together with the increase in hyperemic MBF resulted in a significant increase in the myocardial flow reserve during metoprolol (3.14 {+-} 0.80-4.61 {+-} 0.68; p<0.01). The {beta}{sub 1} receptor blockade increases coronary vasodilatory capacity and myocardial flow reserve. However, the mechanisms accounting for this finding remain uncertain. 32 refs., 2 figs., 2 tabs.

  7. Biological tracer for waste site characterization

    International Nuclear Information System (INIS)

    Strong-Gunderson, J.

    1995-01-01

    Remediating hazardous waste sites requires detailed site characterization. In groundwater remediation, characterizing the flow paths and velocity is a major objective. Various tracers have been used for measuring groundwater velocity and transport of contaminants, colloidal particles, and bacteria and nutrients. The conventional techniques use dissolved solutes, dyes. and gases to estimate subsurface transport pathways. These tracers can provide information on transport and diffusion into the matrix, but their estimates for groundwater flow through fractured regions are very conservative. Also, they do not have the same transport characteristics as bacteria and suspended colloid tracers, both of which must be characterized for effective in-place remediation. Bioremediation requires understanding bacterial transport and nutrient distribution throughout the acquifer, knowledge of contaminants s mobile colloidal particles is just essential

  8. Repeatability of regional myocardial blood flow calculation in 82Rb PET imaging

    International Nuclear Information System (INIS)

    Knešaurek, Karin; Machac, Josef; Zhang, Zhuangyu

    2009-01-01

    We evaluated the repeatability of the calculation of myocardial blood flow (MBF) at rest and pharmacological stress, and calculated the coronary flow reserve (CFR) utilizing 82 Rb PET imaging. The aim of the research was to prove high repeatability for global MBF and CFR values and good repeatability for regional MBF and CFR values. The results will have significant impact on cardiac PET imaging in terms of making it more affordable and increasing its use. 12 normal volunteers were imaged at rest and during pharmacological stress, with 2220 MBq of 82 Rb each. A GE Advance PET system was used to acquire dynamic 50-frame studies. MBF was calculated with a 2-compartmental model using a modified PMOD program (PMOD; University Hospital Zurich, Zurich, Switzerland). Two differential equations, describing a 2-compartmental model, were solved by numerical integration and using Levenberg-Marquardt's method for fitting data. The PMOD program defines 16 standard segments and calculates myocardial flow for each segment, as well as average septal, anterior, lateral, inferior and global flow. Repeatability was evaluated according to the method of Bland and Altman. Global rest and stress MBF, as well as global CFR, showed very good repeatability. No significant differences were found between the paired resting global MBF (0.63 ± 0.13 vs. 0.64 ± 0.13 mL/min/g; mean difference, -1.0% ± 2.6%) and the stress global MBF (1.37 ± 0.23 vs. 1.37 ± 0.24; mean difference, 0.1% ± 2.3%). Global CFR was highly reproducible (2.25 ± 0.56 vs. 2.22 ± 0.54, P = not statistically significant; mean difference, 1.3% ± 14.3%). Repeatability coefficients for global rest MBF were 0.033 (5.2%) and stress MBF 0.062 (4.5%) mL/min/g. Regional rest and stress MBF and CFR have shown good reproducibility. The average per sector repeatability coefficients for rest MBF were 0.056 (8.5%) and stress MBF 0.089 (6.3%) mL/min/g, and average repeatability coefficient for CFR was 0.25 (10.6%). The results

  9. Myocardial imaging in acute myocardial infarction using β-methyl-p-(123I)-iodophenylpentadecanoic acid

    International Nuclear Information System (INIS)

    Naruse, Hitoshi; Itano, Midoriko; Kondo, Tomohiro

    1992-01-01

    Myocardial imaging using β-methyl-p-( 123 I)-iodophenylpentadecanoic acid (BMIPP) was performed in 11 patients with acute myocardial infarction. The left ventricular images were divided into 12 segments, and myocardial images with BMIPP were compared with coronary angiography (CAG), thallium-201 myocardial scintigraphy (Tl) and wall motion obtained by two-dimensional echocardiography (WM). When the culprit lesion was at the proximal point of the left anterior descending artery (LAD), all segments showed depressed uptake. In 3 cases with single vessel disease of the LAD, inferior wall of the basis showed reduced uptake of BMIPP despite the location of the culprit lesion. In cases with discordant uptake between the two tracers, BMIPP frequently showed more severely depressed uptake than Tl in the subacute phase, although the uptake of BMIPP correlated with that of Tl (τ=0.82, p<0.001). In such cases, the discordance was related to the improvement in WM from the acute phase to the convalescent phase. BMIPP uptake correlated with WM in the subacute phase (τ=0.50, p<0.001). BMIPP showed more severely depressed uptake while WM showed mild asynergy in most cases in which discordance was found between the BMIPP and WM findings. However, there was no correlation between the change in WM from the acute to subacute phases, or the uptakes of BMIPP and Tl alone. We concluded that the myocardial condition can be evaluated in detail in acute myocardial infarction by comparing the findings of BMIPP with those of Tl and WM. (author)

  10. Determination of regional flow by use of intravascular PET tracers: microvascular theory and experimental validation for pig livers

    DEFF Research Database (Denmark)

    Munk, O L; Bass, L; Feng, H

    2003-01-01

    Today, the standard approach for the kinetic analysis of dynamic PET studies is compartment models, in which the tracer and its metabolites are confined to a few well-mixed compartments. We examine whether the standard model is suitable for modern PET data or whether theories including more...... physiologic realism can advance the interpretation of dynamic PET data. A more detailed microvascular theory is developed for intravascular tracers in single-capillary and multiple-capillary systems. The microvascular models, which account for concentration gradients in capillaries, are validated and compared...... with the standard model in a pig liver study. METHODS: Eight pigs underwent a 5-min dynamic PET study after (15)O-carbon monoxide inhalation. Throughout each experiment, hepatic arterial blood and portal venous blood were sampled, and flow was measured with transit-time flow meters. The hepatic dual...

  11. Rapid computation of single PET scan rest-stress myocardial blood flow parametric images by table look up.

    Science.gov (United States)

    Guehl, Nicolas J; Normandin, Marc D; Wooten, Dustin W; Rozen, Guy; Ruskin, Jeremy N; Shoup, Timothy M; Woo, Jonghye; Ptaszek, Leon M; Fakhri, Georges El; Alpert, Nathaniel M

    2017-09-01

    We have recently reported a method for measuring rest-stress myocardial blood flow (MBF) using a single, relatively short, PET scan session. The method requires two IV tracer injections, one to initiate rest imaging and one at peak stress. We previously validated absolute flow quantitation in ml/min/cc for standard bull's eye, segmental analysis. In this work, we extend the method for fast computation of rest-stress MBF parametric images. We provide an analytic solution to the single-scan rest-stress flow model which is then solved using a two-dimensional table lookup method (LM). Simulations were performed to compare the accuracy and precision of the lookup method with the original nonlinear method (NLM). Then the method was applied to 16 single scan rest/stress measurements made in 12 pigs: seven studied after infarction of the left anterior descending artery (LAD) territory, and nine imaged in the native state. Parametric maps of rest and stress MBF as well as maps of left (f LV ) and right (f RV ) ventricular spill-over fractions were generated. Regions of interest (ROIs) for 17 myocardial segments were defined in bull's eye fashion on the parametric maps. The mean of each ROI was then compared to the rest (K 1r ) and stress (K 1s ) MBF estimates obtained from fitting the 17 regional TACs with the NLM. In simulation, the LM performed as well as the NLM in terms of precision and accuracy. The simulation did not show that bias was introduced by the use of a predefined two-dimensional lookup table. In experimental data, parametric maps demonstrated good statistical quality and the LM was computationally much more efficient than the original NLM. Very good agreement was obtained between the mean MBF calculated on the parametric maps for each of the 17 ROIs and the regional MBF values estimated by the NLM (K 1map LM  = 1.019 × K 1 ROI NLM  + 0.019, R 2  = 0.986; mean difference = 0.034 ± 0.036 mL/min/cc). We developed a table lookup method for fast

  12. A multicomponent tracer field experiment to measure the flow volume, surface area, and rectilinear spacing of fractures away from the wellbore

    Science.gov (United States)

    Cathles, L. M.; Sanford, W. E.; Hawkins, A.; Li, Y. V.

    2017-12-01

    The nature of flow in fractured porous media is important to almost all subsurface processes including oil and gas recovery, contaminant transport and remediation, CO2 sequestration, and geothermal heat extraction. One would like to know, under flowing conditions, the flow volume, surface area, effective aperture, and rectilinear spacing of fractures in a representative volume of rock away from the well bore, but no methods currently allow acquisition of this data. It could, however, be collected by deploying inert tracers with a wide range of aqueous diffusion constants (e.g., rapidly diffusing heat to non-diffusing nanoparticle) in the following fashion: The flow volume is defined by the heated volume measured by resistivity surveys. The fracture volume within this flow volume is indicate by the nanoparticle transit time. The average fracture spacing is indicated by the evolving thermal profile in the monitor and the production wells (measured by fiber optic cable), and by the retention of absorbing tracers. The average fracture aperture is determined by permeability measurements and the average fracture separation. We have proposed a field test to redundantly measure these fracture parameters in the fractured Dakota Sandstone where it approaches the surface in Ft Collins, Colorado. Five 30 m deep wells (an injection, production, and 3 monitor wells) cased to 20 m are proposed. The experiments will involve at least 9 different tracers. The planned field test and its potential significance will be described.

  13. Measurement of absolute myocardial blood flow with H215O and dynamic positron-emission tomography. Strategy for quantification in relation to the partial-volume effect

    International Nuclear Information System (INIS)

    Iida, H.; Kanno, I.; Takahashi, A.

    1988-01-01

    An in vivo technique was developed for measuring the absolute myocardial blood flow with H 2 15 O and dynamic positron-emission tomography. This technique was based on a new model involving the concept of the tissue fraction, which was defined as the fraction of the tissue mass in the volume of the region of interest. The myocardium was imaged dynamically by positron-emission tomography, starting at the time of intravenous bolus injection of H 2 15 O. The arterial input function was measured continuously with a beta-ray detector. A separate image after C 15 O inhalation was also obtained for correction of the H 2 15 O radioactivity in the blood. The absolute myocardial blood flow and the tissue fraction were calculated for 15 subjects with a kinetic technique under region-of-interest analysis. These results seem consistent with their coronary angiographic findings. The mean value of the measured absolute myocardial blood flows in normal subjects was 0.95 +/- 0.09 ml/min/g. This technique detected a diffuse decrease of myocardial blood flow in patients with triple-vessel disease

  14. Quantitative assessment of regional myocardial flow reserve using Tc-99m-sestamibi imaging. Comparison with results of O-15 water PET

    International Nuclear Information System (INIS)

    Tsukamoto, Takahiro; Ito, Yoshinori; Noriyasu, Kazuyuki; Morita, Koichi; Katoh, Chietsugu; Okamoto, Hiroshi; Tamaki, Nagara

    2005-01-01

    The aims of this study were to develop a method for quantitative estimation of the myocardial blood flow index (MBFI) and myocardial flow reserve (MFR) of the whole left ventricle using 99m technetium (Tc-99m)-sestamibi imaging. Twenty-two patients with suspected coronary artery disease and 7 controls underwent both Tc-99m-sestamibi imaging and O-15 water positron emission tomography (PET). The global MBFI was calculated on the basis of the microsphere model from the ratio of the myocardial count to the area under the time-activity curve on the aortic arch. The regional MBFI was calculated from the relative distributions of Tc-99m-sestamibi uptake values. The regional MBFI and MFR (Tc-MFR) obtained using single-photon emission computed tomography were compared with the myocardial blood flow (MBF) and MFR (PET-MFR) obtained using PET as the gold standard. Regional MBFI significantly correlated with the MBF obtained using PET. Regional Tc-MFR also correlated with the regional PET-MER, with some underestimation. These results indicate that regional MBF and MFR may be estimated by dynamic Tc-99m-sestamibi imaging and can be used for the early detection and estimation of the functional severity of coronary lesions without the need for a PET camera. (author)

  15. The European Tracer Experiment - experimental results and database

    International Nuclear Information System (INIS)

    Nodop, K.; Connolly, R.; Girardi, F.

    1997-01-01

    As part of the European Tracer Experiment (ETEX) two successful atmospheric experiments were carried out in October and November, 1994. Perfluorocarbon (PFC) tracers were released into the atmosphere in Monterfil, Brittany, and air samples were taken at 168 stations in 17 European countries for 72 hours after the release. Upper air tracer measurements were made from three aircraft. During the first experiment a westerly air flow transported the tracer plume north-eastwards across Europe. During the second release the flow was eastwards. The results from the ground sampling network allowed the determination of the cloud evolution as far as Sweden, Poland and Bulgaria. Typical background concentrations of the tracer used are around 5 to 7 fl/l in ambient air. Concentrations in the plume ranged from 10 to above 200 fl/l. The tracer release characteristics, the tracer concentrations at the ground and in upper air, the routine and additional meteorological observations at the ground level and in upper air, trajectories derived from constant-level balloons and the meteorological input fields for long-range transport (LRT) models are assembled in the ETEX database. The ETEX database is accessible via the Internet

  16. New software for raw data mask processing increases diagnostic ability of myocardial SPECT imaging.

    Science.gov (United States)

    Tanaka, Ryo; Yoshioka, Katsunori; Seino, Kazue; Ohba, Muneo; Nakamura, Tomoharu; Shimada, Katsuhiko

    2011-05-01

    Increased activity of myocardial perfusion tracer technetium-99m in liver and hepatobiliary system causes streak artifacts, which may affect clinical diagnosis. We developed a mask-processing tool for raw data generated using technetium-99m as a myocardial perfusion tracer. Here, we describe improvements in image quality under the influence of artifacts caused by high accumulation in other organs. A heart phantom (RH-2) containing 15 MBq of pertechnetate was defined as model A. Model B was designed in the same phantom containing ten times of cardiac radioactivity overlapping with other organs. Variance in the vertical profile count in the lower part of the myocardial inferior wall and in the myocardial circumferential profile curve were investigated in a phantom and clinical cases using our raw data masking (RDM) software. The profile variances at lower parts of myocardial inferior walls were 965.43 in model A, 1390.11 in model B and 815.85 in B-RDM. The mean ± SD of myocardial circumferential profile curves were 83.91 ± 7.39 in model A, 69.61 ± 11.45 in model B and 82.68 ± 9.71 in model B-RDM. For 11 clinical images with streak artifacts, the average of the variance significantly differed between with and without RDM (3.95 vs. 21.05; P software. The waiting time between infusion and image acquisition should be decreased, thus reducing patient burden and improving the diagnostic ability of the procedure.

  17. Quantitative perfusion parameters in a cohort of patients with no known ischemic heart disease and normal myocardial perfusion imaging studied by 82Rb-PET

    DEFF Research Database (Denmark)

    Hoff, Camilla; Balche, Abdallah; Majgaard, J

    Purpose 82Rb perfusion PET allows for visual as well as quantitative interpretation of myocardial function. Whereas visual interpretation relies on intra-individual redistribution of the tracer between rest and stress studies, quantitative interpretation of absolute flow values requires robust.......86 mL/g/min. Global coronary flow reserve (CFR) was 2.81 (±SD 0.71). EF at rest was 65.3% (±SD 10) and during stress 69% (±SD 12.3), yielding an EF reserve of 4.5%. TPD at rest and stress was 6% (±SD 4). Conclusion Based on a representative population of patients in which coronary artery disease...

  18. The impact of prompt gamma compensation on myocardial blood flow measurements with rubidium-82 dynamic PET.

    Science.gov (United States)

    Armstrong, Ian S; Memmott, Matthew J; Tonge, Christine M; Arumugam, Parthiban

    2018-04-01

    Rubidium-82 myocardial perfusion imaging is a well-established technique for assessing myocardial ischemia. With continuing interest on myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements, there is a requirement to fully appreciate the impact of technical aspects of the process. One such factor for rubidium-82 is prompt gamma compensation (PGC). This study aims to assess the impact of PGC on MBF and MFR calculated from dynamic Rb-82 data. Dynamic rest and stress images were acquired on a Siemens Biograph mCT and reconstructed with and without PGC in 50 patients (29 male). MBF and MFR were measured in the three main coronary territories as well as globally. With PGC, statistically significant reductions in MBF were observed in LAD (-6.9%), LCx (-4.8%), and globally (-6.5%) but only in obese patients. Significant increases in MBF were observed in RCA (+6.4%) in only nonobese patients. In very obese patients, differences of up to 40% in MBF were observed between PGC and non-PGC images. In nearly all cases, similar PGC differences were observed at stress and rest so there were no significant differences in MFR; however, in a small number of very obese patients, differences in excess of 20% were observed. PGC results in statistically significant changes in MBF, with the greatest reductions observed in the LAD and LCx territories of obese patients. In most cases, the impact on stress and rest data is of similar relative magnitudes and changes to MFR are small.

  19. Single-well tracer methods for hydrogeologic evaluation of target aquifers

    International Nuclear Information System (INIS)

    Hall, S.H.

    1994-11-01

    Designing an efficient well field for an aquifer thermal energy storage (ATES) project requires measuring local groundwater flow parameters as well as estimating horizontal and vertical inhomogeneity. Effective porosity determines the volume of aquifer needed to store a given volume of heated or chilled water. Ground-water flow velocity governs the migration of the thermal plume, and dispersion and heat exchange along the flow path reduces the thermal intensity of the recovered plume. Stratigraphic variations in the aquifer will affect plume dispersion, may bias the apparent rate of migration of the plume, and can prevent efficient hydraulic communication between wells. Single-well tracer methods using a conservative flow tracer such as bromide, along with pumping tests and water-level measurements, provide a rapid and cost-effective means for estimating flow parameters. A drift-and-pumpback tracer test yields effective porosity and flow velocity. Point-dilution tracer testing, using new instrumentation for downhole tracer measurement and a new method for calibrating the point-dilution test itself, yields depth-discrete hydraulic conductivity as it is affected by stratigraphy, and can be used to estimate well transmissivity. Experience in conducting both drift-and-pumpback and point-dilution tests at three different test sites has yielded important information that highlights both the power and the limitations of the single-well tracer methods. These sites are the University of Alabama Student Recreation Center (UASRC) ATES well field and the VA Medical Center (VA) ATES well field, both located in Tuscaloosa, Alabama, and the Hanford bioremediation test site north of Richland, Washington

  20. Myocardial distribution of I131-labeled hexadecenoic acid in relation to the dog local coronary flow

    International Nuclear Information System (INIS)

    Riche, F.; Busquet, G.; Pilichowski, P.; Wolf, J.E.; Mathieu, J.P.; Comet, M.; Pernin, C.; Vidal, M.; Vincens, M.; Godart, J.

    1981-01-01

    20 anesthetized and thoracotomized dogs are studied. The local myocardial blood flow is measured with sup(99m)Tc human albumin microspheres. The intramyocardial distribution of the 16-I(131)-9-hexadecenoic acid in relation to local blood flow is studied in basal conditions (7 dogs), after experimental infarction (6 dogs) and postischemic reactive hyperhemia (7 dogs). We conclude that during basal condition, after infarction but not during reactive hyperhemia, the distribution of the labeled fatty acid reflect the local variations of blood flow [fr

  1. Biological characterization of F-18-labeled rhodamine B, a potential positron emission tomography perfusion tracer.

    Science.gov (United States)

    Bartholomä, Mark D; He, Huamei; Pacak, Christina A; Dunning, Patricia; Fahey, Frederic H; McGowan, Francis X; Cowan, Douglas B; Treves, S Ted; Packard, Alan B

    2013-11-01

    Myocardial infarction is the leading cause of death in western countries, and positron emission tomography (PET) plays an increasing role in the diagnosis and treatment planning for this disease. However, the absence of an (18)F-labeled PET myocardial perfusion tracer hampers the widespread use of PET in myocardial perfusion imaging (MPI). We recently reported a potential MPI agent based on (18)F-labeled rhodamine B. The goal of this study was to more completely define the biological properties of (18)F-labeled rhodamine B with respect to uptake and localization in an animal model of myocardial infarction and to evaluate the uptake (18)F-labeled rhodamine B by cardiomyocytes. A total of 12 female Sprague Dawley rats with a permanent ligation of the left anterior descending artery (LAD) were studied with small-animal PET. The animals were injected with 100-150 μCi of (18)F-labeled rhodamine B diethylene glycol ester ([(18)F]RhoBDEGF) and imaged two days before ligation. The animals were imaged again two to ten days post-ligation. After the post-surgery scans, the animals were euthanized and the hearts were sectioned into 1mm slices and myocardial infarct size was determined by phosphorimaging and 2,3,5-triphenyltetrazolium chloride staining (TTC). In addition, the uptake of [(18)F]RhoBDEGF in isolated rat neonatal cardiomyocytes was determined by fluorescence microscopy. Small-animal PET showed intense and uniform uptake of [(18)F]RhoBDEGF throughout the myocardium in healthy rats. After LAD ligation, well defined perfusion defects were observed in the PET images. The defect size was highly correlated with the infarct size as determined ex vivo by phosphorimaging and TTC staining. In vitro, [(18)F]RhoBDEGF was rapidly internalized into rat cardiomyocytes with ~40 % of the initial activity internalized within the 60 min incubation time. Fluorescence microscopy clearly demonstrated localization of [(18)F]RhoBDEGF in the mitochondria of rat cardiomyocytes. Fluorine-18

  2. Biological characterization of F-18-labeled rhodamine B, a potential positron emission tomography perfusion tracer

    International Nuclear Information System (INIS)

    Bartholomä, Mark D.; He, Huamei; Pacak, Christina A.; Dunning, Patricia; Fahey, Frederic H.; McGowan, Francis X.; Cowan, Douglas B.; Treves, S. Ted; Packard, Alan B.

    2013-01-01

    Introduction: Myocardial infarction is the leading cause of death in western countries, and positron emission tomography (PET) plays an increasing role in the diagnosis and treatment planning for this disease. However, the absence of an 18 F-labeled PET myocardial perfusion tracer hampers the widespread use of PET in myocardial perfusion imaging (MPI). We recently reported a potential MPI agent based on 18 F-labeled rhodamine B. The goal of this study was to more completely define the biological properties of 18 F-labeled rhodamine B with respect to uptake and localization in an animal model of myocardial infarction and to evaluate the uptake 18 F-labeled rhodamine B by cardiomyocytes. Methods: A total of 12 female Sprague Dawley rats with a permanent ligation of the left anterior descending artery (LAD) were studied with small-animal PET. The animals were injected with 100–150 μCi of 18 F-labeled rhodamine B diethylene glycol ester ([ 18 F]RhoBDEGF) and imaged two days before ligation. The animals were imaged again two to ten days post-ligation. After the post-surgery scans, the animals were euthanized and the hearts were sectioned into 1 mm slices and myocardial infarct size was determined by phosphorimaging and 2,3,5-triphenyltetrazolium chloride staining (TTC). In addition, the uptake of [ 18 F]RhoBDEGF in isolated rat neonatal cardiomyocytes was determined by fluorescence microscopy. Results: Small-animal PET showed intense and uniform uptake of [ 18 F]RhoBDEGF throughout the myocardium in healthy rats. After LAD ligation, well defined perfusion defects were observed in the PET images. The defect size was highly correlated with the infarct size as determined ex vivo by phosphorimaging and TTC staining. In vitro, [ 18 F]RhoBDEGF was rapidly internalized into rat cardiomyocytes with ∼ 40 % of the initial activity internalized within the 60 min incubation time. Fluorescence microscopy clearly demonstrated localization of [ 18 F]RhoBDEGF in the mitochondria

  3. TracerLPM (Version 1): An Excel® workbook for interpreting groundwater age distributions from environmental tracer data

    Science.gov (United States)

    Jurgens, Bryant C.; Böhlke, J.K.; Eberts, Sandra M.

    2012-01-01

    TracerLPM is an interactive Excel® (2007 or later) workbook program for evaluating groundwater age distributions from environmental tracer data by using lumped parameter models (LPMs). Lumped parameter models are mathematical models of transport based on simplified aquifer geometry and flow configurations that account for effects of hydrodynamic dispersion or mixing within the aquifer, well bore, or discharge area. Five primary LPMs are included in the workbook: piston-flow model (PFM), exponential mixing model (EMM), exponential piston-flow model (EPM), partial exponential model (PEM), and dispersion model (DM). Binary mixing models (BMM) can be created by combining primary LPMs in various combinations. Travel time through the unsaturated zone can be included as an additional parameter. TracerLPM also allows users to enter age distributions determined from other methods, such as particle tracking results from numerical groundwater-flow models or from other LPMs not included in this program. Tracers of both young groundwater (anthropogenic atmospheric gases and isotopic substances indicating post-1940s recharge) and much older groundwater (carbon-14 and helium-4) can be interpreted simultaneously so that estimates of the groundwater age distribution for samples with a wide range of ages can be constrained. TracerLPM is organized to permit a comprehensive interpretive approach consisting of hydrogeologic conceptualization, visual examination of data and models, and best-fit parameter estimation. Groundwater age distributions can be evaluated by comparing measured and modeled tracer concentrations in two ways: (1) multiple tracers analyzed simultaneously can be evaluated against each other for concordance with modeled concentrations (tracer-tracer application) or (2) tracer time-series data can be evaluated for concordance with modeled trends (tracer-time application). Groundwater-age estimates can also be obtained for samples with a single tracer measurement at one

  4. Features of positron emission tomography as a probe for myocardial chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Schelbert, H R

    1986-08-01

    Until recently, the study of the living human heart remained elusive. Knowledge of human myocardial metabolism and biochemistry is still narrowly limited despite a vast array of available investigate techniques. Conventional methods focus primilary on the heart's structure, on coronary anatomy, blood flow, and global or regional function. Arteriovenous sampling approaches for the study of metabolism have shown patterns of substrate utilization and release of end products of metabolism, yet could not provide information on regional metabolism or its chanes in cardiac disease. In addition, these approaches were powerless to determine the metabolic fate of substrates on extracted by myocardium. To overcome these limitations, investigators resorted to radiolabeled tracers of substrates. With these tracers, they were able to determine arteriocoronary sinus activity concentration differences, as well as the chemical form containing the label after release from myocardium. With C-14 palmitate for example,the fractional distribution of palmitate between immediate oxidation and intermediate deposition in endogeneous lipid pools within the myocardium could be determined in vivo. Though representing an advance in investigative ability, these procedures are invasive, provide relatively limited information and remained confined to research domain.

  5. Evaluation of myocardial sympathetic nerve function in patients with mitral valve prolapse using iodine-123-metaiodobenzylguanidine myocardial scintigraphy

    International Nuclear Information System (INIS)

    Kishi, Fumiko; Nomura, Masahiro; Yukinaka, Michiko

    1996-01-01

    Mitral valve prolapse (MVP) is closely related to myocardial sympathetic nerve function. This study evaluated the presence of impaired myocardial sympathetic nerve function by Iodine-123-metaiodobenzylguanidine (MIBG) scintigraphy in nine patients with MVP. For comparison, 15 healthy subjects without heart disease were investigated (control group). Single photon emission computed tomography (SPECT) and anterior planar myocardial scintigraphy were performed 15 min (initial images) and 3 hours (delayed images) after injection of MIBG (111 MBq). The location and degrees of reduced tracer uptake were evaluated. Myocardial MIBG uptake was quantified by uptake ratio of the heart (H) to upper mediastinum (M) on the anterior planar images (H/M). Percentage washout of MIBG in nine sectors of all oblique slices along the short-axis was calculated. The washout rates were higher at the inferoposterior and septal segments in patients with anterior leaflet prolapse, and at inferoposterior and lateral segments in patients with posterior leaflet prolapse. The bull's eye map showed increased washout rate in the apical and posteroseptal basal segments. There was no significant difference in the H/M ratio between MVP patients and the control group. These results indicate that MIBG can be used to evaluate localized myocardial sympathetic nerve function in MVP. (author)

  6. Sci-Fri AM: Imaging - 09: Serial estimation of cross-talk for correction in dual-isotope imaging with dynamic tracers.

    Science.gov (United States)

    Wells, R G; Lockwood, J; Wei, L; Duan, D; Fernando, P; Bensimon, C; Ruddy, T D

    2012-07-01

    The recent radioisotope shortage has led to interest in non-Tc99m-based tracers. We have developed a novel I-123-labelled myocardial perfusion imaging tracer. We compare the I123-tracer to the clinical standard of Tc99m tetrofosmin in vivo in a rat model using a small-animal SPECT/CT camera. SPECT distinguishes different isotopes based on the different energies of the emitted gamma rays and thus allows simultaneous comparison of two tracer distributions in the same animal. Dual-isotope imaging is complicated by cross-talk between the energy windows of the isotopes. Standard energy-window-based correction methods are difficult to employ because of the proximity in energy of Tc99m (140keV) and I123 (159keV). Imaging the second tracer's energy window prior to its injection provides an estimate of the cross-talk. However, this estimate is only accurate if the tracer distribution is static. We use serial imaging prior to the introduction of the second tracer to estimate the dynamics of the first tracer and interpolate the cross-talk images to provide a more accurate correction. We used rat models of myocardial disease (n=3). I123 tracer was injected and imaged for one hour at 20min intervals. The Tc99m tetrofosmin was then injected and 30min later, a dual-isotope image was obtained. The impact of this approach is assessed by comparing the differences in the Tc99m-tetrofosmin image using this method with correction by simple correction for physical decay. The interpolative approach improves the accuracy of the correction by 2%-5% and thereby enhances the comparison of the two tracers. © 2012 American Association of Physicists in Medicine.

  7. Characterization of Japanese standards for myocardial sympathetic and metabolic imaging in comparison with perfusion imaging

    International Nuclear Information System (INIS)

    Matsuo, Shinro; Nakajima, Kenichi; Okuda, Koichi; Yamashina, Shohei; Sakata, Kazuyuki; Momose, Mitsuru; Hashimoto, Jun; Kumita, Shinichiro; Kawano, Masaya

    2009-01-01

    The standard patterns of myocardial radiotracer distribution of 123 I-metaiodobenzylguanidine (MIBG) and 123 I-β-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) should be defined in a Japanese population. The purpose of this study was to present and provide data on the characteristics of MIBG and BMIPP with respect to myocardial single photon emission computed tomography. The normal database included 123 I-MIBG and 123 I-BMIPP imaging and a 99 mTc-sestamibi/tetrofosmin myocardial perfusion study. The projection images were transferred by digital imaging and communications in medicine (DICOM) format and reconstructed and analyzed with polar maps. The projection data from multiple centers were successfully transferred to a common format for single photon emission computed tomography (SPECT) reconstruction. When the average values were analyzed using a 17-segment model, MIBG uptake in the inferior and apical wall appeared to be slightly lower than anterior uptake (P 99m Tc-tracer uptake (P<0.05). Myocardial sympathetic nerve and metabolic scintigraphy data that were specific for the Japanese population were generated and found to be different from that of perfusion tracers. The normal database can serve as a standard for nuclear cardiology work conducted in Japan. (author)

  8. Tracer migration experiments in the Stripa mine 1980-1991

    International Nuclear Information System (INIS)

    Birgersson, L.; Widen, H.; Aagren, T.; Neretnieks, I.

    1992-05-01

    During more than 10 years, tracer experiments have been performed in the Stripa mine as part of the Stripa project to investigate the properties of both 'average' fractured rock and fracture zones. Experiments have been performed that have ranged from a few decimeters, to examine the diffusion into the rock matrix, up to tracer migration to a drift more than 50 meters from the injection point. This report compiles the results and experience that have been gained from all these tracer experiments. The experiments that are described in this report are: * The in-situ diffusion experiment where simultaneous flow and diffusion of tracers in undisturbed rock were studied over more than 3 years to validate diffusivities obtained under laboratory conditions. * Migration in a single fracture where water flow distribution and tracer transport were studied using both conservative and sorbing tracers over migration distances up to 10 meters. * The 3-D migration experiment where water inflow and tracer transport to a drift covered with 350 plastic sheet were investigated to get information on flow porosity, dispersion and channeling. The transport distances were between 10 and 56 meters from the injection points to the drift. * The channeling experiments in which the aim was to examine the channeling properties of single fractures in detail. Pressure pulse tests and tracer experiments were performed over a distances of 2 meters. * The tracer migration experiment in the validation drift where the tracer were injected mainly in a fracture zone and the collection was inside both a drift covered with plastic sheets similar to in the 3-D experiment as well as in a borehole. The distances between injection and sampling location were between 10 and 25 meters. (57 refs.) (au)

  9. Dynamic HDA-123-I-myocardial scintigraphy after aortocoronary bypass grafting

    International Nuclear Information System (INIS)

    Fridrich, L.; Gassner, A.; Sommer, G.; Kneussl, M.; Pichler, M.; Klicpera, M.; Salomonowitz, E.

    1986-01-01

    In an attempt to evaluate the dynamics of fatty acid metabolism after aortocoronary bypass grafting (ACBG), ten patients were investigated after ACBG by HDA-I-123 myocardial scintigraphy. Tracer kinetics were followed for 90 min and compared to those of 36 non-grafted patients with different underlying heart diseases, including healthy volunteers. Regional analysis and mono-exponential curve fitting were used to evaluate tsub(1/2) (half-life of the early period of tracer elimination); biexponential curve analysis was used to calculate Ca/Cb, the ratio of a fast and a slow component of tracer elimination. Rest and stress MUGA-RNV served as discriminating parameters to discern between patient groups with normal and abnormal ventricular function. Group I (normal controls) encompassed ten patients with normal ventricular function, including three after ACBG, and group II seven patients after ACBG and with abnormal ventricular function. Group III had coronary artery disease (CAD) documented by angiography, and group IV by prior myocardial infarction. Group V included patients with cardiomyopathy. Regional analysis of group II revealed no significant differences to control regions (Gr I) for tsub(1/2) or Ca/Cb, but showed for Ca/Cb a nonsignificant shift toward group III values. However, group II differed significantly from group III and V. three patients with normal ventricular function after ACBG showed elimination values that were all well within the range of completely normal individuals. Thus our data support the assumption that a normal function is indicative of a normal metabolism. Following myocardial fatty acid metabolism during rest might be a helpful noninvasive tool for etiologic differentiation of disturbed ventricular function. (orig.)

  10. Correlation between thallium-201 myocardial perfusion defects and the functional severity of coronary artery stenosis as assessed by pressure-derived myocardial fractional flow reserve

    International Nuclear Information System (INIS)

    Yanagisawa, Hidefumi; Chikamori, Taishiro; Tanaka, Nobuhiro

    2002-01-01

    Although a relationship between the coronary pressure-derived fractional flow reserve (FFR) and the presence of myocardial ischemia as demonstrated by radionuclide imaging has been reported in a select group of patients, it remains to be established whether this relation also holds true in actual clinical settings with a heterogeneous group of patients. Accordingly, 194 coronary vessels and their supply territories were evaluated in 165 consecutive patients with suspected or known coronary artery disease. An FFR 201 Tl (p 201 Tl reversibility score (r=-0.62; p<0.0001). These results suggest that the FFR has a significant relationship with scintigraphic evidence of myocardial ischemia and can be regarded as a marker of its presence or absence in patients in actual clinical settings. (author)

  11. Myocardial blood flow and its transit time, oxygen utilization, and efficiency of highly endurance-trained human heart.

    Science.gov (United States)

    Heinonen, Ilkka; Kudomi, Nobuyuki; Kemppainen, Jukka; Kiviniemi, Antti; Noponen, Tommi; Luotolahti, Matti; Luoto, Pauliina; Oikonen, Vesa; Sipilä, Hannu T; Kopra, Jaakko; Mononen, Ilkka; Duncker, Dirk J; Knuuti, Juhani; Kalliokoski, Kari K

    2014-07-01

    Highly endurance-trained athlete's heart represents the most extreme form of cardiac adaptation to physical stress, but its circulatory alterations remain obscure. In the present study, myocardial blood flow (MBF), blood mean transit time (MTT), oxygen extraction fraction (OEF) and consumption (MVO2), and efficiency of cardiac work were quantified in highly trained male endurance athletes and control subjects at rest and during supine cycling exercise using [(15)O]-labeled radiotracers and positron emission tomography. Heart rate and MBF were lower in athletes both at rest and during exercise. OEF increased in response to exercise in both groups, but was higher in athletes (70 ± 21 vs. 63 ± 11 % at rest and 86 ± 13 vs. 73 ± 10 % during exercise). MTT was longer and vascular resistance higher in athletes both at rest and during exercise, but arterial content of 2,3-diphosphoglycerate (oxygen affinity) was unchanged. MVO2 per gram of myocardium trended (p = 0.08) lower in athletes both at rest and during exercise, while myocardial efficiency of work and MVO2 per beat were not different between groups. Arterial levels of free fatty acids were ~twofold higher in athletes likely leading to higher myocardial fatty acid oxidation and hence oxygen cost, which may have blunted the bradycardia-induced decrease in MVO2. Finally, the observed group differences in MBF, OEF, MTT and vascular resistance remained significant also after they were controlled for differences in MVO2. In conclusion, in highly endurance-trained human heart, increased myocardial blood transition time enables higher oxygen extraction levels with a lower myocardial blood flow and higher vascular resistance. These physiological adaptations to exercise training occur independently of the level of oxygen consumption and together with training-induced bradycardia may serve as mechanisms to increase functional reserve of the human heart.

  12. Myocardial perfusion imaging for the detection of coronary heart disease

    International Nuclear Information System (INIS)

    Strauss, H.W.; Cook, D.J.; Bailey, I.; Rouleau, J.; Pitt, B.

    1976-01-01

    A method of myocardial perfusion imaging using 201 Tl is described. Thallium is able to substitute for potassium in biological systems including transport by the sodium--potassium ATP-ase system. The high extraction efficiency of the heart for 201 Tl offers a method whereby a tracer may be administered intravenously and is concentrated to a significant degree by the heart. However, only about 3 to 4 percent of the dose administered lodges in the myocardium. Experiments with dogs indicated that the regional distribution of Tl in the heart reflects the regional distribution of blood flow. The goal is to develop a procedure that can detect those patients with significant disease prior to the onset of a catastrophic event and studies are being undertaken to improve the sensitivity of the method for the detection of smaller lesions in the myocardium

  13. A comparison of measurements and calculations for the Stripa tracer experiments

    International Nuclear Information System (INIS)

    Hodgkinson, D.P.; Copper, N.S.

    1992-03-01

    This paper presents a comparison of measurements and predictions for migration of tracers from boreholes to the validation drift and to other boreholes in the Site Characterisation and Validation (SCV) block. The comparison was carried out on behalf of the Stripa task force on fracture flow modelling. The paper summarises the radar/saline tracer experiments, the tracer migration experiment observations and reviews the fracture flow and tracer transport modelling approaches and predictions made by AEA Technology, Fracflow Consultants, Golder Associates and Lawrence Berkeley Laboratory. The predictions are compared with the observed breakthrough curves on the basis of the validation process and criteria defined by the task force. The results of all four modelling groups met the validation criteria, with the predictions of the tracer breakthrough concentrations and times being within an order of magnitude of the observations. Also the AEA and Golder approaches allow the spatial distribution of tracer breakthrough into the validation drift to be predicted and these predictions also showed reasonable accuracy. The successful completion of this project demonstrates the feasibility of discrete fracture flow and tracer transport modelling. (36 refs.) (au)

  14. Prognostic value of coronary blood flow velocity and myocardial perfusion in intermediate coronary Narrowings and multivessel disease

    NARCIS (Netherlands)

    Chamuleau, SAJ; Tio, RA; de Cock, CC; de Muinck, ED; Pijls, NHJ; van Eck-Smit, BLF; Koch, KT; Meuwissen, M; Dijkgraaf, MGW; Verberne, HJ; van Liebergen, RAM; Laarman, GJ; Tijssen, JGP; Piek, JJ; de Jong, A.

    2002-01-01

    OBJECTIVES This study aimed to investigate the roles of intracoronary derived coronary flow velocity reserve (CFVR) and myocardial perfusion scintigraphy (single photon emission computed tomography, or SPECT) for management of an intermediate lesion in patient, with multivessel coronary artery

  15. Hydraulic characterisation of karst systems with man-made tracers

    International Nuclear Information System (INIS)

    Werner, A.

    1998-01-01

    Tracer experiments using man-made tracers are common in hydrogeological exploration of groundwater aquifers in karst systems. In the present investigation, a convection-dispersion model (multidispersion model with consideration of several flow paths) and a single-cleft model (consideration of the diffusion between the cleft and the surrounding rock matrix) were used for evaluating tracer experiments in the main hydrological system of the saturated zone of karst systems. In addition to these extended analytical solutions, a numerical transport model was developed for investigating the influence of the transient flow rate on the flow and transport parameters. Comparative evaluations of the model approaches for the evaluation of tracer experiments were made in four different karst systems: Danube-Aach, Paderborn, Slowenia and Lurbach, of which the Danube-Aach system was considered as the most important. The investigation also comprised three supplementary experiments in order to enable a complete hydraulic characterisation of the system. (orig./SR) [de

  16. Quantification of myocardial area at risk in the absence of collateral flow: the validation of angiographic scores by myocardial perfusion single-photon emission computed tomography.

    Science.gov (United States)

    Rodríguez-Palomares, José F; Alonso, Albert; Martí, Gerard; Aguadé-Bruix, Santiago; González-Alujas, M T; Romero-Farina, Guillermo; Candell-Riera, Jaume; García del Blanco, Bruno; Evangelista, Artur; García-Dorado, David

    2013-02-01

    Our study aimed to compare the area at risk (AAR) determined by single-photon emission computed tomography (SPECT) with the Bypass Angioplasty Revascularization Investigation (BARI) and modified Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) angiographic scores in the setting of patients undergoing coronary angioplasty for either unstable angina or an STEMI. Radionuclide myocardial perfusion imaging prior to reperfusion has classically been the most widely practised technique for assessing the AAR and has been successfully used to compare the efficacy of various reperfusion strategies in patients with an ST-segment elevation myocardial infarction (STEMI). The BARI and modified APPROACH scores are angiographic methods widely used to provide a rapid estimation of the AAR; however, they have not been directly validated with myocardial perfusion single-photon emission computed tomography (SPECT). Fifty-five patients with no previous myocardial infarction who underwent coronary angioplasty for single-vessel disease (unstable angina: n = 25 or an STEMI: n = 30) with no evidence of collaterals (Rentrop Collateral Score collateral flow, BARI and APPROACH scores constitute valid methods for AAR estimation in current clinical practice, with more accurate results when used for the LAD territory; both are useful not only in STEMI patients but also in patients with unstable angina.

  17. Lumped parameter models for the interpretation of environmental tracer data

    Energy Technology Data Exchange (ETDEWEB)

    Maloszewski, P [GSF-Inst. for Hydrology, Oberschleissheim (Germany); Zuber, A [Institute of Nuclear Physics, Cracow (Poland)

    1996-10-01

    Principles of the lumped-parameter approach to the interpretation of environmental tracer data are given. The following models are considered: the piston flow model (PFM), exponential flow model (EM), linear model (LM), combined piston flow and exponential flow model (EPM), combined linear flow and piston flow model (LPM), and dispersion model (DM). The applicability of these models for the interpretation of different tracer data is discussed for a steady state flow approximation. Case studies are given to exemplify the applicability of the lumped-parameter approach. Description of a user-friendly computer program is given. (author). 68 refs, 25 figs, 4 tabs.

  18. Lumped parameter models for the interpretation of environmental tracer data

    International Nuclear Information System (INIS)

    Maloszewski, P.; Zuber, A.

    1996-01-01

    Principles of the lumped-parameter approach to the interpretation of environmental tracer data are given. The following models are considered: the piston flow model (PFM), exponential flow model (EM), linear model (LM), combined piston flow and exponential flow model (EPM), combined linear flow and piston flow model (LPM), and dispersion model (DM). The applicability of these models for the interpretation of different tracer data is discussed for a steady state flow approximation. Case studies are given to exemplify the applicability of the lumped-parameter approach. Description of a user-friendly computer program is given. (author). 68 refs, 25 figs, 4 tabs

  19. Kinetics of 13N-ammonia uptake in myocardial single cells indicating potential limitations in its applicability as a marker of myocardial blood flow

    International Nuclear Information System (INIS)

    Rauch, B.; Helus, F.; Grunze, M.; Braunwell, E.; Mall, G.; Hasselbach, W.; Kuebler, W.

    1985-01-01

    To study kinetics and principles of cellular uptake of 13 N-ammonia, a marker of coronary perfusion in myocardial scintigraphy, heart muscle cells of adult rats were isolated by perfusion with collagenase and hyaluronidase. Net uptake of 13 N, measured by flow dialysis, reached equilibrium within 20 sec in the presence of sodium bicarbonate and carbon dioxide (pH 7.4, 37 degrees C). Total extraction, 80 sec after the reaction start, was 786 +/- 159 mumol/ml cell volume. Cells destroyed by calcium overload were unable to extract 13 N-ammonia. Omission of bicarbonate and carbon dioxide reduced total extraction to 36% of control. 13 N-Ammonia uptake could also be reduced by 50 muM 4,4' diisothiocyanostilbene 2,2' disulfonic acid, by 100 micrograms/ml 1-methionine sulfoximine, and by preincubation with 5 muM free oleic acid. These results indicate that in addition to metabolic trapping by glutamine synthetase, the extraction of 13 N-ammonia by myocardial cells is influenced by cell membrane integrity, intracellular-extracellular pH gradient, and possibly an anion exchange system for bicarbonate. For this reason, the uptake of 13 N-ammonia may not always provide a valid measurement of myocardial perfusion

  20. Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 1, in-situ measurements of flow dynamics, tracer particle movement and video imagery from the summer of 2009

    Science.gov (United States)

    McCoy, Scott W.; Coe, Jeffrey A.; Kean, Jason W.; Tucker, Greg E.; Staley, Dennis M.; Wasklewicz, Thad A.

    2011-01-01

    Debris flows initiated by surface-water runoff during short duration, moderate- to high-intensity rainfall are common in steep, rocky, and sparsely vegetated terrain. Yet large uncertainties remain about the potential for a flow to grow through entrainment of loose debris, which make formulation of accurate mechanical models of debris-flow routing difficult. Using a combination of in situ measurements of debris flow dynamics, video imagery, tracer rocks implanted with passive integrated transponders (PIT) and pre- and post-flow 2-cm resolution digital terrain models (terrain data presented in a companion paper by STALEY et alii, 2011), we investigated the entrainment and transport response of debris flows at Chalk Cliffs, CO, USA. Four monitored events during the summer of 2009 all initiated from surface-water runoff, generally less than an hour after the first measurable rain. Despite reach-scale morphology that remained relatively constant, the four flow events displayed a range of responses, from long-runout flows that entrained significant amounts of channel sediment and dammed the main-stem river, to smaller, short-runout flows that were primarily depositional in the upper basin. Tracer-rock travel-distance distributions for these events were bimodal; particles either remained immobile or they travelled the entire length of the catchment. The long-runout, large-entrainment flow differed from the other smaller flows by the following controlling factors: peak 10-minute rain intensity; duration of significant flow in the channel; and to a lesser extent, peak surge depth and velocity. Our growing database of natural debris-flow events can be used to develop linkages between observed debris-flow transport and entrainment responses and the controlling rainstorm characteristics and flow properties.

  1. Myocardial ischemia in hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Lima Filho, Moyses de Oliveira; Figueiredo, Geraldo L.; Simoes, Marcus V.; Pyntia, Antonio O.; Marin Neto, Jose Antonio

    2000-01-01

    Myocardial ischemia in hypertrophic cardiomyopathy is multifactorial and explains the occurrence of angina, in about 50% of patients. The pathophysiology of myocardial ischemia may be explained by the increase of the ventricular mass and relative paucity of the coronary microcirculation; the elevated ventricular filling pressures and myocardial stiffness causing a compression of the coronary microvessels; the impaired coronary vasodilator flow reserve caused by anatomic and functional abnormalities; and the systolic compression of epicardial vessel (myocardial bridges). Myocardial ischemia must be investigated by perfusion scintigraphic methods since its presence influences the prognosis and has relevant clinical implications for management of patients. Patients with hypertrophic cardiomyopathy and documented myocardial ischemia usually need to undergo invasive coronary angiography to exclude the presence of concomitant atherosclerotic coronary disease. (author)

  2. Thallium-201 for myocardial imaging: appearance of the normal heart

    International Nuclear Information System (INIS)

    Cook, D.J.; Bailey, I.; Strauss, H.W.; Rouleau, J.; Wagner, H.N. Jr.; Pitt, B.

    1976-01-01

    Thallium-201 myocardial perfusion images were obtained from 13 healthy adults after tracer administration both at rest and at maximal stress. On the rest-injected scan, tracer was seen in left ventricular myocardium, liver, and spleen. In two subjects with resting tachycardia, the right ventricular myocardium was slightly visualized after tracer injection at rest. When tracer was administered at stress, the left ventricular activity was more nearly homogeneous and the left ventricle was better defined on the scan. The left-ventricle-to-lung-background activity ratio increased from 2.4 at rest to 3.4 at stress. The right ventricular myocardium was seen on the stress-injected scan. Phantom studies, performed to define the optimum position for visualization of lesions, showed that small lesions were best defined when seen either en face or in tangent. Scans should be performed at stress whenever possible and multiple views are essential

  3. Characterization of eco-friendly fluorescent nanoparticle-doped tracers for environmental sensing

    International Nuclear Information System (INIS)

    Tauro, Flavia; Rapiti, Emiliano; Al-Sharab, Jafar F.; Ubertini, Lucio; Grimaldi, Salvatore; Porfiri, Maurizio

    2013-01-01

    Particle tracers are extensively used in quantitative flow visualization and environmental sensing. In this paper, we provide a thorough characterization of the novel eco-friendly fluorescent particle tracers formulated in Tauro et al. (AIP Adv 3(3): 032108, 2013). The tracers are synthesized from natural beeswax and are functionalized by encapsulating nontoxic fluorophore nanoparticles in the beads’ matrix through an inexpensive thermal procedure. Visibility and durability studies are conducted through a wide array of techniques to investigate the tracers’ surface morphological microfeatures, crystal nature and size, chemical composition, fluorophore incorporation into the beeswax matrix, and fluorescence response under severe settings resembling exposure to natural environments. Our findings demonstrate that fluorescent nanoparticles ranging from 1.51 to 3.73 nm are homogeneously distributed in the superficial layer (12 nm) of the tracers. In addition, fluorescence emissions are observed up to 26 days of continuous exposure of the tracers to high energy radiation. To demonstrate the particles’ use in environmental flow sensing, a set of proof of concept outdoor tests are conducted, in which image analysis tools are utilized for detecting the fluorescent tracers. Experimental results suggest that fluorescent microparticles deployed in high flow-rate flows (2 m/s) and under direct sunlight can be sensed through commercially available cameras (frame rate set to 30 Hz)

  4. COMPARISON OF THREE TRACER TESTS AT THE RAFT RIVER GEOTHERMAL SITE

    Energy Technology Data Exchange (ETDEWEB)

    Earl D Mattson; Mitchell Plummer; Carl Palmer; Larry Hull; Samantha Miller; Randy Nye

    2011-02-01

    Three conservative tracer tests have been conducted through the Bridge Fault fracture zone at the Raft River Geothermal (RRG) site. All three tests were conducted between injection well RRG-5 and production wells RRG-1 (790 m distance) and RRG-4 (740 m distance). The injection well is used during the summer months to provide pressure support to the production wells. The first test was conducted in 2008 using 136 kg of fluorescein tracer. Two additional tracers were injected in 2010. The first 2010 tracer injected was 100 kg fluorescein disodium hydrate salt on June, 21. The second tracer (100 kg 2,6-naphthalene disulfonic acid sodium salt) was injected one month later on July 21. Sampling of the two productions wells is still being performed to obtain the tail end of the second 2010 tracer test. Tracer concentrations were measured using HPLC with a fluorescence detector. Results for the 2008 test, suggest 80% tracer recover at the two production wells. Of the tracer recovered, 85% of tracer mass was recovered in well RRG-4 indicating a greater flow pathway connection between injection well and RRG-4 than RRG-1. Fluorescein tracer results appear to be similar between the 2008 and 2010 tests for well RRG-4 with peak concentrations arriving approximately 20 days after injection despite the differences between the injection rates for the two tests (~950 gpm to 475 gpm) between the 2008 and 2010. The two 2010 tracer tests will be compared to determine if the results support the hypothesis that rock contraction along the flow pathway due to the 55 oC cooler water injection alters the flow through the ~140 oC reservoir.

  5. On the use of flow-storage repartitions derived from artificial tracer tests for geothermal reservoir characterization in the Malm-Molasse basin: a theoretical study

    Science.gov (United States)

    Dewi, Dina Silvia; Osaigbovo Enomayo, Augustine; Mohsin, Rizwan; Karmakar, Shyamal; Ghergut, Julia; Sauter, Martin

    2016-04-01

    Flow-storage repartition (FSR) analysis (Shook 2003) is a versatile tool for characterizing subsurface flow and transport systems. FSR can be derived from measured signals of inter-well tracer tests, if certain requirements are met - basically, the same as required for equivalence between fluid residence time distribution (RTD) and a measured inter-well tracer signal (pre-processed and de-convolved if necessary). Nominally, a FSR is derived from a RTD as a trajectory in normalized {1st, 0th}-order statistical moment space; more intuitively, as a parametric plot of 0th-order against 1st-order statistical moments of RTD truncated at time t, with t as a parameter running from the first tracer input to the latest available tracer sampling; 0th-order moments being normalized by the total tracer recovery, and 1st-order moments by the mean RT. Fracture-dominated systems plot in the upper left (high F , low S) region of FSR diagrams; a homogeneous single-continuum with no dispersion (infinite Peclet number) displays a straight line from {F ,S}={0,0} to {F ,S}={1,1}. This analysis tool appears particularly attractive for characterizing markedly-heterogeneous, porous-fissured-fractured (partly karstified) formations like those targeted by geothermal exploration in the Malm-Molasse basin in Southern Germany, and especially for quantifying flow and transport contributions from contrasting facies types ('reef' versus 'bedded'). However, tracer tests conducted in such systems with inter-well distances of some hundreds of metres (as required by economic considerations on geothermal reservoir sizing) face the problem of very long residence times - and thus the need to deal with incomplete (truncated) signals. For the geothermal well triplet at the Sauerlach site near Munich, tracer peak arrival times exceeding 2 years have been predicted, and signal tails decreasing by less than 50% over >10 years, which puts great uncertainty on the (extrapolation-based) normalizing factors

  6. Optimization of flow reserve measurement using SPECT technology to evaluate the determinants of coronary microvascular dysfunction in diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Marini, Cecilia [CNR Institute of Bioimages and Molecular Physiology, Milan, Section of Genoa (Italy); Bezante, GianPaolo; Modonesi, Elisa; Rollando, Daniela; Balbi, Manrico; Brunelli, Claudio [University of Genoa, Department of Internal Medicine, Cardiology, Genoa (Italy); Gandolfo, Patrizia; Morbelli, Silvia D.; Armonino, Riccardo [University of Genoa, Department of Internal Medicine, Nuclear Medicine, Genoa (Italy); DePascale, Angelo; Maggi, Davide; Albertelli, Manuela; Cordera, Renzo [University of Genoa, Department of Endocrinological Metabolic Sciences, Diabetology, Genoa (Italy); Sambuceti, Gianmario [University of Genoa, Department of Internal Medicine, Nuclear Medicine, Genoa (Italy); Advanced Biotechnology Center, Genoa (Italy)

    2010-02-15

    The aim of this study was to validate a new method to measure regional myocardial perfusion reserve (MPR) with technetium-labelled tracers in patients with type 2 diabetes mellitus (DM2). A total of 40 consecutive DM2 patients without history of coronary artery disease (CAD) and 7 control subjects were recruited. Dipyridamole myocardial blood flow index (MBF) was assessed by measuring first transit counts in the pulmonary artery and myocardial count rate from gated SPECT images using {sup 99m}Tc-labelled tracers. The corresponding MBF index was estimated 2 h later according to the same procedure. Regional myocardial perfusion reserve (MPR) was defined as the ratio between dipyridamole and baseline MBF using a 17-segment left ventricular (LV) model. Coronary flow reserve (CFR) was estimated by transthoracic contrast echo Doppler monitoring of flow velocity in the left anterior descending coronary artery (LAD) during the same session. Estimated MPR was higher in control subjects than in patients (3.36 {+-} 0.66 vs 1.91 {+-} 0.61, respectively, p < 0.01). In patients, LAD CFR and LAD MPR were 2.01 {+-} 0.78 vs 1.93 {+-} 0.63, respectively (p = ns). The agreement between the two techniques was documented by their close correlation (r = 0.92, p < 0.001) and confirmed by the Bland-Altman analysis. Reversible perfusion defects occurred in 13 patients (32%) who showed similar MPR values as the remaining 27 (2.10 {+-} 0.71 vs 1.83 {+-} 0.71, respectively, p = ns). Finally, MPR was closely correlated with age (r = -0.50, p < 0.01) and time elapsed from the diagnosis of DM2 (r = -0.51, p < 0.01). LV regional MPR can be accurately estimated with the broadly available single photon technology. Application of this method to DM2 patients documents the presence of a microvascular dysfunction homogeneously distributed throughout the LV walls and most frequently not associated with reversible perfusion defects. (orig.)

  7. Nanoparticle tracers in calcium carbonate porous media

    KAUST Repository

    Li, Yan Vivian

    2014-07-15

    Tracers are perhaps the most direct way of diagnosing subsurface fluid flow pathways for ground water decontamination and for natural gas and oil production. Nanoparticle tracers could be particularly effective because they do not diffuse away from the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles are not retained in the porous media as the result of aggregation or sticking to mineral surfaces. By screening eight nanoparticles (3-100 nm in diameter) for retention when passed through calcium carbonate packed laboratory columns in artificial oil field brine solutions of variable ionic strength we show that the nanoparticles with the least retention are 3 nm in diameter, nearly uncharged, and decorated with highly hydrophilic polymeric ligands. The details of these column experiments and the tri-modal distribution of zeta potential of the calcite sand particles in the brine used in our tests suggests that parts of the calcite surface have positive zeta potential and the retention of negatively charged nanoparticles occurs at these sites. Only neutral nanoparticles are immune to at least some retention. © 2014 Springer Science+Business Media.

  8. Myocardial distribution of I/sup 131/-labeled hexadecenoic acid in relation to the dog local coronary flow

    Energy Technology Data Exchange (ETDEWEB)

    Riche, F.; Busquet, G.; Pilichowski, P.; Wolf, J.E.; Mathieu, J.P.; Comet, M.; Pernin, C. (Centre Hospitalier Regional, 38 - Grenoble (France)); Vidal, M.; Vincens, M.; Godart, J. (Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires)

    1981-01-01

    20 anesthetized and thoracotomized dogs are studied. The local myocardial blood flow is measured with sup(99m)Tc human albumin microspheres. The intramyocardial distribution of the 16-I(131)-9-hexadecenoic acid in relation to local blood flow is studied in basal conditions (7 dogs), after experimental infarction (6 dogs) and postischemic reactive hyperhemia (7 dogs). We conclude that during basal condition, after infarction but not during reactive hyperhemia, the distribution of the labeled fatty acid reflect the local variations of blood flow.

  9. Modelling tracer transport in fractured rock at Stripa

    International Nuclear Information System (INIS)

    Herbert, A.

    1992-01-01

    We present the results of a modelling study, making predictions for tracer transport experiments carried out within the H-zone feature in the Stripa mine. We use a direct fracture network approach to represent the system of interconnected flow-conducting fractures comprising this zone. It is a highly fractured granite, and our fracture-network models include up to 60000 fractures. We have had to develop efficient algorithms to calculate the flow and transport through these networks; these techniques are described and justified. The first stage of modelling addressed two saline injection experiments. The results of these were known to us and so in addition to 'predicting' the results of these experiments, we used them to calibrate a flow model of the experimental site. This model was then used to make true 'blind' predictions for a set of tracer experiments carried out in the natural head-field, caused by an open drift. Where our flow model was good, our predictions were found to be very accurate, explaining the dispersion in the tracer breakthrough in terms of the fracture network geometry. Discrepancies for experiments in less well characterised regions of the H-zone are presented, and we suggest that the errors in these predictions are a consequence of the inaccuracies of the flow-field. We have demonstrated the use of large-scale fracture network modelling. It has proved very successful, and made very accurate predictions of field experiments carried out at the Stripa mine. The measured dispersion of tracers can be accounted for by the geometry of the fracture network flow system. (14 refs.) (au)

  10. Predictions of tracer transport in interwell tracer tests at the C-Hole complex. Yucca Mountain site characterization project report milestone 4077

    International Nuclear Information System (INIS)

    Reimus, P.W.

    1996-09-01

    This report presents predictions of tracer transport in interwell tracer tests that are to be conducted at the C-Hole complex at the Nevada Test Site on behalf of the Yucca Mountain Site Characterization Project. The predictions are used to make specific recommendations about the manner in which the tracer test should be conducted to best satisfy the needs of the Project. The objective of he tracer tests is to study flow and species transport under saturated conditions in the fractured tuffs near Yucca Mountain, Nevada, the site of a potential high-level nuclear waste repository. The potential repository will be located in the unsaturated zone within Yucca Mountain. The saturated zone beneath and around the mountain represents the final barrier to transport to the accessible environment that radionuclides will encounter if they breach the engineered barriers within the repository and the barriers to flow and transport provided by the unsaturated zone. Background information on the C-Holes is provided in Section 1.1, and the planned tracer testing program is discussed in Section 1.2

  11. Sodium bicarbonate-augmented stress thallium myocardial scintigraphy

    International Nuclear Information System (INIS)

    Sarin, Badal; Chugh, Pradeep Kumar; Kaushal, Dinesh; Soni, Nakse Lal; Sawroop, Kishan; Mondal, Anupam; Bhatnagar, Aseem

    2004-01-01

    It is well known that sodium bicarbonate in pharmacological doses induces transient alkalosis, causing intracellular transport of serum potassium. The aims of this study were (a) to investigate whether, in humans, myocardial thallium-201 uptake can be augmented by pretreatment with a single bolus of sodium bicarbonate at a pharmacological dose, (b) to verify general safety aspects of the intervention and (c) to evaluate the clinical implications of augmentation of 201 Tl uptake, if any. Routine exercise myocardial scintigraphy was performed twice in eight adult volunteers (five normal and three abnormal), once without intervention and the second time (within a week) following intravenous administration of sodium bicarbonate (88 mEq in 50 ml) as a slow bolus 1 h prior to the injection of 201 Tl. Conventional myocardial thallium study was compared with sodium bicarbonate interventional myocardial scintigraphy with respect to myocardial uptake (counts per minute per mCi injected dose), washout patterns in normal and abnormal myocardial segments, and overall clinical interpretation based on planar and single-photon emission tomographic (SPET) images. All patients remained asymptomatic after the intervention. A mean increase of 53% in myocardial uptake of thallium was noted in post-exercise acquisitions after the intervention, confirming uptake of the tracer via the potassium-hydrogen pump and its augmentation by transient alkalosis. The washout pattern remained unchanged. The visual quality of planar and SPET images improved significantly after the intervention. Out of the five abnormal myocardial segments identified in three cases, four showed significant filling-in after the intervention, causing the diagnosis to be upgraded from ''partial scar'' to ''ischaemia'', or from ''ischaemia'' to ''normal''. The overall scan impression changed in two out of three such cases. Sodium bicarbonate augmentation may have significant implications for stress-thallium scintigraphy

  12. CT myocardial perfusion imaging. Ready for prime time?

    Energy Technology Data Exchange (ETDEWEB)

    Takx, Richard A.P.; Celeng, Csilla [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Ashley River Tower, Heart and Vascular Center, Charleston, SC (United States)

    2018-03-15

    The detection of functional coronary artery stenosis with coronary CT angiography (CCTA) is suboptimal. Additional CT myocardial perfusion imaging (CT-MPI) may be helpful to identify patients with myocardial ischaemia in whom coronary revascularization therapy would be beneficial. CT-MPI adds incremental diagnostic and prognostic value over obstructive disease on CCTA. It allows for the quantitation of myocardial blood flow and calculation of coronary flow reserve and shows good correlation with {sup 15}O-H{sub 2}O positron emission tomography and invasive fractional flow reserve. In addition, patients prefer CCTA/CT-MPI over SPECT, MRI and invasive coronary angiography. CT-MPI is ready for clinical use for detecting myocardial ischaemia caused by obstructive disease. Nevertheless, the clinical utility of CT-MPI to identify ischaemia in patients with non-obstructive/microvascular disease still has to be established. (orig.)

  13. Serial thallium-201 imaging after dipyridamole for coronary disease detection: quantitative analysis using myocardial clearance

    International Nuclear Information System (INIS)

    Okada, R.D.; Dai, Y.H.; Boucher, C.A.; Pohost, G.M.

    1984-01-01

    After dipyridamole, canine studies have demonstrated a slower rate of myocardial thallium-201 clearance from zones distal to a coronary artery stenosis compared to normal zones. To determine if criteria based on canine myocardial thallium-201 clearance rates could be applied clinically, 40 patients with and 26 patients without coronary artery disease (CAD) had serial thallium-201 images obtained for 2 to 5 hours after dipyridamole. Regions of interest were manually placed over six left ventricular segments in two projections for each of three imaging times. The myocardial thallium-201 clearance rate was calculated for each of the six segments and, using the clearance rate criterion found in canine studies, was considered abnormal if less than 6.5%/hr. Using this criterion alone, 22 of 26 patients (85%) without CAD had normal and 30 of 40 patients (75%) with CAD had abnormal myocardial thallium-201 clearance rates. A quantitative analysis of regional inhomogeneity in tracer distribution (normal was greater than or equal to 25% difference between segments) was negative in 24 of 26 patients (92%) without CAD and positive in 20 of 40 patients (50%) with CAD. When both clearance rate and regional inhomogeneity were considered, 21 of 26 patients (81%) without CAD had negative and 36 of 40 patients (90%) with CAD had positive results. Thus, post-dipyridamole myocardial clearance rate criteria derived from canine studies can be applied to clinical thallium imaging. Quantitative analysis of serial thallium-201 images after dipyridamole is optimized by using myocardial thallium-201 clearance rates. Such an approach is independent of regional inhomogeneities in tracer distribution

  14. Segmental quantitative analysis of digital thallium-201 myocardial scintigrams in diagnosis of coronary artery disease

    International Nuclear Information System (INIS)

    Wainwright, R.J.; Maisey, M.N.; Sowton, E.

    1981-01-01

    One hundred and forty-nine patients with suspected ischaemic heart disease were evaluated by exercise thallium-201 myocardial scintigraphy ( 201 Tl SMS), single lead exercise electrocardiography, and coronary arteriography. Myocardial distribution of tracer was assessed semi-quantitatively from digital 201 Tl scintigrams and compared with tracer distribution in subjects with normal hearts. Fifty-two of 54 (96%) patients with normal coronary arteries had normal myocardial scintigrams whereas three patients had a positive ischaemic exercise electrocardiogram and were scan normal. Conversely, 36 of 95 (38%) patients with coronary artery disease had a positive ischaemic electrocardiogram compared with 94 of 95 (99%) patients who had a positive myocardial scintigram. Disease was predicted correctly in 76 out of 80 (95%) of left anterior descending coronary stenoses, in 48 out of 64 (75%) of right coronary artery stenoses, and in 55 out of 64 (85%) of left circumflex coronary artery stenoses, despite the presence of infarcted myocardium in other territories. 201 Tl SMS with segmental quantitative analysis is a highly sensitive and specific technique in the diagnosis of coronary artery disease and may be a useful screening procedure to select patients for further investigation, particularly those with evidence of life-threatening severe left coronary artery disease. (author)

  15. Transport of Perfluorocarbon Tracers in the Cranfield Geological Carbon Sequestration Project

    Science.gov (United States)

    Moortgat, J.; Soltanian, M. R.; Amooie, M. A.; Cole, D. R.; Graham, D. E.; Pfiffner, S. M.; Phelps, T.

    2017-12-01

    A field-scale carbon dioxide (CO2) injection pilot project was conducted by the Southeast Regional Sequestration Partnership (SECARB) at Cranfield, Mississippi. Two associated campaigns in 2009 and 2010 were carried out to co-inject perfluorocarbon tracers (PFTs) and sulfur hexafluoride (SF6) with CO2. Tracers in gas samples from two observation wells were analyzed to construct breakthrough curves. We present the compiled field data as well as detailed numerical modeling of the flow and transport of CO2, brine, and introduced tracers. A high-resolution static model of the formation geology in the Detailed Area Study (DAS) was used in order to capture the impact of connected flow pathways created by fluvial channels on breakthrough curves and breakthrough times of PFTs and SF6 tracers. We use the cubic-plus-association (CPA) equation of state, which takes into account the polar nature of water molecules, to describe the phase behavior of CO2-brine-tracer mixtures. We show how the combination of multiple tracer injection pulses with detailed numerical simulations provide a powerful tool in constraining both formation properties and how complex flow pathways develop over time.

  16. Detection technique of radioactive tracer and its application to the flow problems

    International Nuclear Information System (INIS)

    Sato, Otomaru; Kato, Masao

    1978-01-01

    With a radioactive tracer experiment the nature of the system and the precision are the two key factors to determine the amount of the required tracer. It should be kept as low as possible to meet environmental regulations. The former factor is concerned with the isotope dilution during the experiment and the latter with counting techniques. In part 1, some counting techniques are investigated while three field experiments are described in part 2. Chemical treatments of water sample are described firstly in part 1. Recovery of the order of 95% was achieved with 24 Na, 131 I and 82 Br by either ion exchange or precipitation technique. Three direct γ-ray counting techniques are investigated secondly, e.g. dip counting method, pipe counting technique, and plane source counting technique. Thirdly, counting characteristics of a moving radioactive source was investigated. A small source was stuck on a moving belt and the center of a GM tube was faced to the belt. The counting rates with or without a collimator were analyzed using a simple equation. In part 2, the first experiment is on the flow rate of the Sorachi river in summer 1961. Measurements by an underwater detector and from periodically collected samples were compared at every observing stations. The second experiment was on the sorption loss of the isotopes in the river in 1963. Very little sorption loss was recognized with 82 Br, while a sorption loss of 10% was found with 24 Na after 6 km downflow. Isotopes were found to mix transversely after 7 to 10 km flow. The third experiment is concerned with the investigation on the movement of sediments at Okuma coast in Fukushima prefecture. (J.P.N.)

  17. Regional glucose utilization and blood flow in experimental brain tumors studied by double tracer autoradiography

    Energy Technology Data Exchange (ETDEWEB)

    Kato, A.; Sako, K.; Diksic, M.; Yamamoto, Y.L.; Feindel, W.

    1985-01-01

    Coupling of regional glucose utilization (GLU) and blood flow (CBF) was examined in rats with implanted brain tumors (AA ascites tumor) by quantitative double tracer autoradiography using YF-2-fluorodeoxyglucose and 14C-iodoantipyrine. Four to 13 days after implantation, the animals were injected with the two tracers to obtain autoradiograms from the same brain section before and after the decay of YF. The autoradiograms were then analyzed by an image processor to obtain a metabolic coupling index (MCI = GLU/CBF). In the tumor, high GLU and low CBF were uncoupled to give a high MCI which implied anerobic glycolysis. In large tumors, the CBF was even lower. In the peri-tumoral region, GLU was reduced and reduction was lowest around the larger tumors. CBF in the peri-tumoral region was also reduced, but this reduction became less as the distance from the tumor margin increased. The GLU and CBF of white matter was little influenced by the presence of tumors except for some reduction in these values in relation to the larger tumors. The MCI in the tumor was higher than in the cortex of the same as well as the opposite hemisphere. These findings indicate that the metabolism and blood flow of the tumor and surrounding brain are variable and directly related to tumor size.

  18. Determination of the self purification of streams using tracers

    International Nuclear Information System (INIS)

    Salviano, J.S.

    1982-04-01

    A methodology for the 'in situ' evaluation of the self purification of streams is discussed. It consists of the simultaneous injection of two tracers into the stream. One of the tracers is oxidized by biochemical processes. It can be either artificially supplied to the stream or a naturally present component can be used. This tracer is used for the determination of the self purification parameters. The other tracer is conservative and allows for the hydrodynamic effects. Tests have been carried out in two streams with quite different hydrodynamic and physicochemical conditions. In the first stream, with a flow-rate of about 0.9 m 3 /s, urea was used as the nonconservative tracer. In the other stream, which had a flow-rate of about 5 m 3 /s, only a radioactive tracer has been used, and the rate of biochemical oxidation has been determined from BOD measurements. Calculations have been implemented on a digital computer. In both cases it was found that the reoxygenation rate is more conveniently determined by empirical formulas. Results from both tests have been deemed realistic by comparison with similar experiments. (Author) [pt

  19. Detection of viable myocardium in canine model with myocardial ischemia and ischemia-reperfusion by 125I-BMIPP: relation to regional blood flow

    International Nuclear Information System (INIS)

    Huang Gang; Zhao Huiyang; Shen Xuedong; Li Qing; Yuan Jimin; Zhu Cuiying

    1999-01-01

    Objective: The effects of BMIPP (β-methyl-iodophenyl pentadecanoic acid) on detecting viable myocardium and the relation between regional blood flow and the uptake of BMIPP were evaluated in canine model of myocardial ischemia and ischemia-reperfusion. Methods: 12 open-chest dogs under anesthesia were divided into two groups. Group I (ischemia group) had left circumflex coronary arterial occlusion for 2 h and group II (ischemia-reperfusion group) was occluded for 1 h and followed by 2 h reperfusion. Myocardial blood flow was measured with 99 Tc m -microspheres. 30 min after intravenous injection of 125 I-BMIPP and 99 Tc m -microspheres, the heart was excised rapidly and stained with Evans blue and NBT. Tissue samples (divided into approximately 1 g) of left ventricle were obtained, weighed and counted for 125 I and 99 Tc m . Regional blood flow and the uptake of BMIPP were expressed as percentages of average values in non-ischemic myocardium (two to three tissue samples) from the normal myocardium. Results: In ischemic myocardium (NBT positive samples), the uptake of BMIPP was relatively higher compared with regional blood flow [(67 +- 23)% vs (42 +- 19)%, P 0.05]. In ischemia-reperfusion group, regional blood flow was increased in ischemic and necrotic tissues, but the uptake of BMIPP was not enhanced with the increasing blood flow. Conclusions: BMIPP uptake seems to provide metabolic information independent of regional blood flow. The mismatching between regional blood flow and BMIPP uptake may indicate myocardial viability in the regions of hypoperfusion and the uptake of BMIPP in ischemic myocardium was related to existence of cellular metabolism

  20. Serial assessment of myocardial thallium perfusion and fatty acid utilization in spontaneously hypertensive rats

    International Nuclear Information System (INIS)

    Sago, Masayoshi; Nishimura, Tsunehiko

    1989-01-01

    To evaluate the advantage of free fatty acid imaging on the detection of hypertrophied myocardium, we compared sequentially myocardial thallium and BMIPP (15-(p-iodophenyl)-3-(R,S)-methyl pentadecanoic acid) distribution in spontaneously hypertensive rat (SHR) using dual tracer autoradiography and in vivo pin-hole imaging. Autoradiography and pin-hole imaging showed uniform myocardial distribution of BMIPP and thallium within less than 27 weeks age SHR. In 40 weeks age SHR, thallium myocardial distribution showed uniform, however, BMIPP had focal decrease. Quantitative analysis of pin-hole images showed that myocardial BMIPP and thallium uptake ratio decreased according to the ages of SHR. Our data suggest that hypertension is associated with uniform myocardial perfusion and focal alternation in the substrate used for the performance of myocardial work. Based on the above autoradiographic and in vivo pin-hole imagings, I-123 BMIPP imaging may have a potential for early detection on hypertrophic myocardium compared to thallium perfusion in clinically hypertensive patients. (author)

  1. Meta-Analysis of Stress Myocardial Perfusion Imaging

    Science.gov (United States)

    2017-06-06

    Coronary Disease; Echocardiography; Fractional Flow Reserve, Myocardial; Hemodynamics; Humans; Magnetic Resonance Imaging; Myocardial Perfusion Imaging; Perfusion; Predictive Value of Tests; Single Photon Emission Computed Tomography; Positron Emission Tomography; Multidetector Computed Tomography; Echocardiography, Stress; Coronary Angiography

  2. Measurement of absolute myocardial blood flow in humans using dynamic cardiac SPECT and 99mTc-tetrofosmin: Method and validation.

    Science.gov (United States)

    Shrestha, Uttam; Sciammarella, Maria; Alhassen, Fares; Yeghiazarians, Yerem; Ellin, Justin; Verdin, Emily; Boyle, Andrew; Seo, Youngho; Botvinick, Elias H; Gullberg, Grant T

    2017-02-01

    The objective of this study was to measure myocardial blood flow (MBF) in humans using 99m Tc-tetrofosmin and dynamic single-photon emission computed tomography (SPECT). Dynamic SPECT using 99m Tc-tetrofosmin and dynamic positron emission tomography (PET) was performed on a group of 16 patients. The SPECT data were reconstructed using a 4D-spatiotemporal iterative reconstruction method. The data corresponding to 9 patients were used to determine the flow-extraction curve for 99m Tc-tefrofosmin while data from the remaining 7 patients were used for method validation. The nonlinear tracer correction parameters A and B for 99m Tc-tefrofosmin were estimated for the 9 patients by fitting the flow-extraction curve [Formula: see text] for K 1 values estimated with 99m Tc-tefrofosmin using SPECT and MBF values estimated with 13 N-NH 3 using PET. These parameters were then used to calculate MBF and coronary flow reserve (CFR) in three coronary territories (LAD, RCA, and LCX) using SPECT for an independent cohort of 7 patients. The results were then compared with that estimated with 13 N-NH 3 PET. The flow-dependent permeability surface-area product (PS) for 99m Tc-tefrofosmin was also estimated. The estimated flow-extraction parameters for 99m Tc-tefrofosmin were found to be A = 0.91 ± 0.11, B = 0.34 ± 0.20 (R 2  = 0.49). The range of MBF in LAD, RCA, and LCX was 0.44-3.81 mL/min/g. The MBF between PET and SPECT in the group of independent cohort of 7 patients showed statistically significant correlation, r = 0.71 (P < .001). However, the corresponding CFR correlation was moderate r = 0.39 yet statistically significant (P = .037). The PS for 99m Tc-tefrofosmin was (0.019 ± 0.10)*MBF + (0.32 ± 0.16). Dynamic cardiac SPECT using 99m Tc-tetrofosmin and a clinical two-headed SPECT/CT scanner can be a useful tool for estimation of MBF.

  3. Flow dynamics and energy efficiency of flow in the left ventricle during myocardial infarction.

    Science.gov (United States)

    Vasudevan, Vivek; Low, Adriel Jia Jun; Annamalai, Sarayu Parimal; Sampath, Smita; Poh, Kian Keong; Totman, Teresa; Mazlan, Muhammad; Croft, Grace; Richards, A Mark; de Kleijn, Dominique P V; Chin, Chih-Liang; Yap, Choon Hwai

    2017-10-01

    Cardiovascular disease is a leading cause of death worldwide, where myocardial infarction (MI) is a major category. After infarction, the heart has difficulty providing sufficient energy for circulation, and thus, understanding the heart's energy efficiency is important. We induced MI in a porcine animal model via circumflex ligation and acquired multiple-slice cine magnetic resonance (MR) images in a longitudinal manner-before infarction, and 1 week (acute) and 4 weeks (chronic) after infarction. Computational fluid dynamic simulations were performed based on MR images to obtain detailed fluid dynamics and energy dynamics of the left ventricles. Results showed that energy efficiency flow through the heart decreased at the acute time point. Since the heart was observed to experience changes in heart rate, stroke volume and chamber size over the two post-infarction time points, simulations were performed to test the effect of each of the three parameters. Increasing heart rate and stroke volume were found to significantly decrease flow energy efficiency, but the effect of chamber size was inconsistent. Strong complex interplay was observed between the three parameters, necessitating the use of non-dimensional parameterization to characterize flow energy efficiency. The ratio of Reynolds to Strouhal number, which is a form of Womersley number, was found to be the most effective non-dimensional parameter to represent energy efficiency of flow in the heart. We believe that this non-dimensional number can be computed for clinical cases via ultrasound and hypothesize that it can serve as a biomarker for clinical evaluations.

  4. Interpretation of the tracer testing conducted in the Leuggern borehole

    International Nuclear Information System (INIS)

    McNeish, J.A.; Andrews, R.W.; Vomvoris, S.

    1990-12-01

    Tracer testing was conducted in the Leuggern borehole from July to December 1988 to evaluate the hydraulic properties of the crystalline host rock. The tested interval was an approximately 50 m section of fractured crystalline rock at a depth of greater than 1,600 m. The testing consisted of three tracer injection/recovery periods (uranin - 44 days, eosin - 30 days, and naphtionat -14 days), which utilized tracer injection/circulation rates, ranging between 25 and 50 ml/min. During these testing periods, tracer was injected in either of two 1/4 flow lines ported at the top or bottom of the interval and recovered from the other. Following the three tracer injection periods, a natural outflow tracer recovery test was conducted from the central tubing at an average outflow of 12 l/min. The central tubing was ported near the center of the test interval. Data collected during the testing periods included: continuous monitoring of fluid temperature, injection pressure, and electrical conductivity as well as discrete measurement of flow rates, electrical conductivity, fluid temperature, and tracer concentration. Testing results indicate a downward vertical flow of approximately 195-225 ml/min in the isolated interval, from an upper fracture inflow zone to a lower fracture outflow zone. Through analysis of the dilution levels of uranin and eosin during the injection/recovery periods, and review of field data, the top of the upper inflow zone was determined to be approximately 13 m below the top flow line and the bottom of the outflow zone to be approximately 3 to 5 meters above the bottom flow line. The calculated transmissivity value of 6E-05 m 2 /s from observed outflow rate and pressure recovery data, is consistent with results derived from previous hydraulic packer testing in the interval. The effective porosity was determined to be 0.1. Dispersion coefficient values ranged from 1.0 m to 5.0 m. The lateral hydraulic gradient value calculated from tracer recovery

  5. Tracer tests - possibilities and limitations. Experience from SKB fieldwork: 1977-2007

    Energy Technology Data Exchange (ETDEWEB)

    Loefgren, Martin; Crawford, James; Elert, Mark (Kemakta Konsult AB, Stockholm (SE))

    2007-09-15

    Tracer tests have played, and still play, a central role in investigations relating to the understanding of radionuclide retention processes in the field. At present there is a debate within the scientific community concerning how, and to what extent, tracer tests can be used to evaluate large-scale and long-term transport and retardation of radionuclides and other solutes of interest for Safety Assessment of repositories for spent nuclear fuel. In this report the SKB fieldwork on tracer tests performed at Swedish sites from 1977 to 2007 is described and discussed. Furthermore, the knowledge and process understanding evolved during the decades of radionuclide transport experiments and modelling within the SKB programme is summarised. One of the main objectives of this report is to discuss what data and knowledge can be extracted from different in situ tests in a robust fashion. Given the level of complexity associated with transport processes that may occur over the timescale of a tracer test, the utility of tracer tests is considered in the context of evidence-based interpretations of data which we characterise in the form of a sequence of questions of increasing complexity. The complexity of this sequence ranges from whether connection can be confirmed between injection and withdrawal points to whether quantitative data can be extrapolated from a tracer test to be subsequently used in Safety Assessment. The main findings of this report are that: Field scale tracer tests can confirm flow connectivity. Field scale tracer tests confirm the existence of retention. Field scale tracer tests alone can only broadly substantiate our process understanding. However, if performing extensive Site Characterisation and integrating the tracer test results with the full range of geoscientific information available, much support can be given to our process understanding. Field scale tracer tests can deliver the product of the material property group MPG and the F-factor, valid

  6. Recover Act. Verification of Geothermal Tracer Methods in Highly Constrained Field Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Matthew W. [California State University, Long Beach, CA (United States)

    2014-05-16

    The prediction of the geothermal system efficiency is strong linked to the character of the flow system that connects injector and producer wells. If water flow develops channels or “short circuiting” between injection and extraction wells thermal sweep is poor and much of the reservoir is left untapped. The purpose of this project was to understand how channelized flow develops in fracture geothermal reservoirs and how it can be measured in the field. We explored two methods of assessing channelization: hydraulic connectivity tests and tracer tests. These methods were tested at a field site using two verification methods: ground penetrating radar (GPR) images of saline tracer and heat transfer measurements using distributed temperature sensing (DTS). The field site for these studies was the Altona Flat Fractured Rock Research Site located in northeastern New York State. Altona Flat Rock is an experimental site considered a geologic analog for some geothermal reservoirs given its low matrix porosity. Because soil overburden is thin, it provided unique access to saturated bedrock fractures and the ability image using GPR which does not effectively penetrate most soils. Five boreholes were drilled in a “five spot” pattern covering 100 m2 and hydraulically isolated in a single bedding plane fracture. This simple system allowed a complete characterization of the fracture. Nine small diameter boreholes were drilled from the surface to just above the fracture to allow the measurement of heat transfer between the fracture and the rock matrix. The focus of the hydraulic investigation was periodic hydraulic testing. In such tests, rather than pumping or injection in a well at a constant rate, flow is varied to produce an oscillating pressure signal. This pressure signal is sensed in other wells and the attenuation and phase lag between the source and receptor is an indication of hydraulic connection. We found that these tests were much more effective than constant

  7. Wirelessly powered micro-tracer enabled by miniaturized antenna and microfluidic channel

    International Nuclear Information System (INIS)

    Duan, G; Zhao, X; Seren, H R; Chen, C; Zhang, X

    2015-01-01

    A miniaturized antenna, 380μm by 380μm in size, was fabricated and integrated with a commercialized passive RFID chip to form a micro-tracer, whose size was 2mm by 1mm in total. The micro-tracer was wirelessly powered and interrogated by a single layer spiral reader antenna through near field coupling. To maximize the working distance, the resonant frequency of micro-tracer and reader antenna were matched at 840MHz. Due to the ultra small size of the tracer antenna, power transfer efficiency decreased dramatically as the distance between tracer antenna and reader antenna increased, thus the working distance of the microtracer was limited within 1mm. To achieve massive operation of the micro-tracer, a microfluidic platform was fabricated with in channel focusing and separation. Acrylic sheets were laser cut to define the channel and cover structure, then bonded together layer by layer with a glass substrate, on which reader antenna was integrated. Pump oil was used as the fluidic media carrying the micro-tracer flowing inside the microfluidic channel. The wireless power transfer and real-time communication was demonstrated with the micro-tracer flowing above the reader antenna, as the ID of the micro-tracer was retrieved and displayed on a computer screen. (paper)

  8. Myocardial accumulation of a dopamine D[sub 2] receptor-binding radioligand, 2'-iodospiperone

    Energy Technology Data Exchange (ETDEWEB)

    Saji, Hideo; Yonekura, Yoshiharu; Tanahashi, Kiyoko; Iida, Yasuhiko; Iwasaki, Yasushi; Magata, Yasuhiro; Konishi, Junji; Yokoyama, Akira [Kyoto Univ. (Japan). Faculty of Medicine

    1993-08-01

    [sup 125]I-iodospiperone (2'-ISP), which has a high and selective affinity for dopamine D[sub 2] receptors, produced a high myocardial accumulation of radioactivity in the early phase after intravenous injection into mice. A human scintigraphic study also showed that the myocardium was clearly visualized soon after intravenous injection of the tracer. Analysis of the myocardial homogenate obtained from mice showed that [sup 125]I-2'-ISP was metabolically stable and was taken up by the myocardium in its intact form. Administration of spiperone significantly reduced the myocardial uptake of [sup 125]I-2'-ISP in mice. Treatment with haloperidol and (+) butaclamol, which have a high affinity for dopamine D[sub 2] receptors, also tended to reduce the myocardial uptake of radioactivity, while (-)-butaclamol, which has no affinity for dopamine D[sub 2] receptors, caused no change in uptake. These findings suggest that the myocardial accumulation of 2'-ISP occurred in association with dopamine D[sub 2] (DA[sub 2]) receptors. (author).

  9. Concentration dynamics in lakes and reservoirs. Studies using radioactive tracers

    International Nuclear Information System (INIS)

    Gilath, Ch.

    1983-01-01

    The use of radioactive tracers for the investigation of concentration dynamics of inert soluble matter in lakes and reservoirs is reviewed. Shallow and deep stratified lakes are considered. The mechanism of mixing in lakes, flow pattern and input - output response are discussed. The methodology of the use of radioactive tracers for concentration dynamic studies is described. Examples of various investigations are reviewed. The dynamics of shallow lakes can be found and expressed in terms of transfer functions, axial dispersion models, residence time distributions and sometimes only semiquantitative information about the flow pattern. The dynamics of deep, stratified lakes is more complex and difficult to investigate with tracers. Flow pattern, horizontal and vertical eddy diffusivities, mass transfer between the hypolimnion and epilimnion are tools used for describing this dynamics. (author)

  10. Investigation by tracer method of water balance in filling the gob with slurries

    International Nuclear Information System (INIS)

    Jureczko, J.; Skowronek, E.

    1977-01-01

    Results of investigations on the establishment of conditions of water flow in filling old workings with mud, in order to determine the degree of water hazard for mine workings in one of mines are given. For the inspection of flow, the stable tracer method and the neutron activation analysis were used. Chromium as a complex compound with EDTA was used as tracer. Geological and mining conditions in the area of investigations by tracers are given and the disposal of diluted stowing slurry is characterized. The method of interpretation of results is discussed in order to determine the water flow rate in the gob and to draw up the water balance on the basis of the curve of tracer travel. (author)

  11. Value of 201-thallium serial myocardial imaging in coronary heart disease

    International Nuclear Information System (INIS)

    Sauer, E.; Sebening, H.; Dressler, J.; Lutilsky, L.; Ulm, K.; Hoer, G.; Papst, H.W.; Bloemer, H.; Technische Univ. Muenchen; Technische Univ. Muenchen

    1979-01-01

    There has been clinical evidence that a perfusion defect on a stress image fills overtime. The diagnostic value of initial and 120 min post exercise redistribution thallium-201 myocardial images (RMI) was determined in 120 pts, with suspected coronary heart disease (CAD), all of whom had coronary arteriography. Significant (>= 75%) lesions were present in 88 pts. 30 pts. without CAD showed a normal tracer uptake immediately after exercise. Scintigrams taken 120 min after exercise revealed a decrease of 201-Tl concentration in every area of the myocardium. 80 pts. with CAD showed an area of decreased tracer uptake in the inital scans. 120 min RMI in 51 pts. revealed a significant increase (p > 0.01) of countrate time ratio in previous underperfused areas. In 37 pts. persistent defects were present, in every case the defect correlated with the site of a myocardial infarction as determined by the finding of an akinetic area in the left ventricular angiogram. Thus RMI following a single dose of 201 Tl can differentiate between scar- and exercise-induced transient ischemia. (orig.) 891 AJ/orig. 892 MB [de

  12. INTRAVAL Finnsjoen Test - modelling results for some tracer experiments

    International Nuclear Information System (INIS)

    Jakob, A.; Hadermann, J.

    1994-09-01

    This report presents the results within Phase II of the INTRAVAL study. Migration experiments performed at the Finnsjoen test site were investigated. The study was done to gain an improved understanding of not only the mechanisms of tracer transport, but also the accuracy and limitations of the model used. The model is based on the concept of a dual porosity medium, taking into account one dimensional advection, longitudinal dispersion, sorption onto the fracture surfaces, diffusion into connected pores of the matrix rock, and sorption onto matrix surfaces. The number of independent water carrying zones, represented either as planar fractures or tubelike veins, may be greater than one, and the sorption processes are described either by linear or non-linear Freundlich isotherms assuming instantaneous sorption equilibrium. The diffusion of the tracer out of the water-carrying zones into connected pore space of the adjacent rock is calculated perpendicular to the direction of the advective/dispersive flow. In the analysis, the fluid flow parameters are calibrated by the measured breakthrough curves for the conservative tracer (iodide). Subsequent fits to the experimental data for the two sorbing tracers strontium and cesium then involve element dependent parameters providing information on the sorption processes and on its representation in the model. The methodology of fixing all parameters except those for sorption with breakthrough curves for non-sorbing tracers generally worked well. The investigation clearly demonstrates the necessity of taking into account pump flow rate variations at both boundaries. If this is not done, reliable conclusions on transport mechanisms or geometrical factors can not be achieved. A two flow path model reproduces the measured data much better than a single flow path concept. (author) figs., tabs., 26 refs

  13. Usefulness of myocardial parametric imaging to evaluate myocardial viability in experimental and in clinical studies.

    Science.gov (United States)

    Korosoglou, G; Hansen, A; Bekeredjian, R; Filusch, A; Hardt, S; Wolf, D; Schellberg, D; Katus, H A; Kuecherer, H

    2006-03-01

    To evaluate whether myocardial parametric imaging (MPI) is superior to visual assessment for the evaluation of myocardial viability. Myocardial contrast echocardiography (MCE) was assessed in 11 pigs before, during, and after left anterior descending coronary artery occlusion and in 32 patients with ischaemic heart disease by using intravenous SonoVue administration. In experimental studies perfusion defect area assessment by MPI was compared with visually guided perfusion defect planimetry. Histological assessment of necrotic tissue was the standard reference. In clinical studies viability was assessed on a segmental level by (1) visual analysis of myocardial opacification; (2) quantitative estimation of myocardial blood flow in regions of interest; and (3) MPI. Functional recovery between three and six months after revascularisation was the standard reference. In experimental studies, compared with visually guided perfusion defect planimetry, planimetric assessment of infarct size by MPI correlated more significantly with histology (r2 = 0.92 versus r2 = 0.56) and had a lower intraobserver variability (4% v 15%, p < 0.05). In clinical studies, MPI had higher specificity (66% v 43%, p < 0.05) than visual MCE and good accuracy (81%) for viability detection. It was less time consuming (3.4 (1.6) v 9.2 (2.4) minutes per image, p < 0.05) than quantitative blood flow estimation by regions of interest and increased the agreement between observers interpreting myocardial perfusion (kappa = 0.87 v kappa = 0.75, p < 0.05). MPI is useful for the evaluation of myocardial viability both in animals and in patients. It is less time consuming than quantification analysis by regions of interest and less observer dependent than visual analysis. Thus, strategies incorporating this technique may be valuable for the evaluation of myocardial viability in clinical routine.

  14. Radioactive or natural tracer techniques for leak determining of dam abutment

    International Nuclear Information System (INIS)

    Chen Jiansheng; Du Guoping; Zheng Zheng; Sun Jing

    1995-01-01

    Infiltration and localization of preferential infiltration zones at the dam abutment are measured using radioactive tracer tests of flow in boreholes, meanwhile interconnection between boreholes and the observing water points is analysed. The theory and practice of radioactive tracer synthetic detective method are described to give methods and calculation formulae used under the condition of stable flow in single well to measure permeability coefficient and hydrostatic heads. Major single hole techniques including measurement for seepage line, velocity, rate of seepage flow and relationship of recharge of groundwater in aquifers are introduced briefly. The possibilities offered by natural tracers are analysed, including electric-conduct, ph-value and temperature of water as well as stable isotopes (D, 18 O) and tritium. Furthermore, the sensibilities of this theory and methods were confirmed by detecting seepage flow field of Xinanjiang Dam

  15. Dynamic 123-I-HDA myocardial scintigraphy: which parameters are useful

    International Nuclear Information System (INIS)

    Fridrich, L.; Gassner, A.; Sykora, J.; Mostbeck, G.; Vagner, M.; Pichler, M.

    1984-01-01

    32 patients underwent dynamic myocardial imaging using I-123-HDA at rest. Of these, 12 had undergone coronary angiography including 6 with coronary bypass; 8 were post myocardial infarction, 8 had cardiomyopathies and 6 were normal. As radionuclide ventriculography at rest and on exertion had been done throughout, fatty acid turnover and global as well as regional function data were available for comparison. In contrast to most of the earlier studies which did not go beyond the early phase of tracer kinetics, i.e. the first 40 minutes, and thus seem to be suggestive of a monoexponential pattern, the acquisition time in our study was extended to 90 minutes. In addition, the kinetic profile of the tracer was evaluated both mono-exponentially (early phase) and bi-exponentially. Unlike the 70-minute acquisition time, this provides for a better identification of the late phase. Mono-exponential evaluation showed half-lifes of 20 to 45 minutes. Using the be-exponential method, half-lifes of 5 to 19 minutes were found for the rapid elimination phase. The ratio between the rapid and the slow component of fatty acid elimination was equally determined. Ratios <1.0 sensitively predict the presence of CHD or CMP. In the latter condition the uncorrected early phase already shows a clearly prolonged elimination half-life. Computing the fast tracer elimination half-life alone after allowing for the slow component has sofar not been found to be a clinically useful criterion. (Author)

  16. Statistical dynamic imaging of RI-labeled tracer from list-mode PET data

    International Nuclear Information System (INIS)

    Tanimoto, Michiaki; Kuroda, Yoshihiro; Oshiro, Osamu; Watabe, Hiroshi; Kuroda, Tomohiro

    2009-01-01

    Positron emission tomography (PET) can be used in physiological analysis to illustrate physiological states by visualizing the accumulation of radioisotope (RI)-labeled tracer in specific organs or tissues. PET obtains spatio-temporal statistics in the form of list-mode data. However, conventional imaging techniques, which sum up list-mode data over a given time period, cannot depict detailed temporal dynamics of the RI-labeled tracer. In this study, a spatio-temporal analysis approach was employed to visualize the temporal flow dynamics of RI-labeled tracer from the obtained list-mode data. Experiments to assess the visualization of simulated RI-labeled tracer dynamics as well as RI-labeled tracer dynamics in a vascular phantom showed that the proposed method successfully depicted detailed temporal flow dynamics that could not be visualized using conventional methods. (author)

  17. Computed tomography myocardial perfusion vs {sup 15}O-water positron emission tomography and fractional flow reserve

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Michelle C.; Dweck, Marc R.; Golay, Saroj K. [University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Edinburgh (United Kingdom); Mirsadraee, Saeed; Weir, Nicholas W.; Fletcher, Alison; Lucatelli, Christophe; Reid, John H. [University of Edinburgh, Clinical Research Imaging Centre, Edinburgh (United Kingdom); MacGillivray, Tom; Van Beek, Edwin J.R.; Newby, David E. [University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Edinburgh (United Kingdom); University of Edinburgh, Clinical Research Imaging Centre, Edinburgh (United Kingdom); Cruden, Nicholas L.; Henriksen, Peter A.; Uren, Neal [Edinburgh Heart Centre, Royal Infirmary of Edinburgh, Edinburgh (United Kingdom); McKillop, Graham; Patel, Dilip [Department of Radiology, Royal Infirmary of Edinburgh, Edinburgh (United Kingdom); Lima, Joao A.C. [Johns Hopkins Hospital, Departments of Medicine and Radiology, Baltimore, MD (United States)

    2017-03-15

    Computed tomography (CT) can perform comprehensive cardiac imaging. We compared CT coronary angiography (CTCA) and CT myocardial perfusion (CTP) with {sup 15}O-water positron emission tomography (PET) and invasive coronary angiography (ICA) with fractional flow reserve (FFR). 51 patients (63 (61-65) years, 80 % male) with known/suspected coronary artery disease (CAD) underwent 320-multidetector CTCA followed by ''snapshot'' adenosine stress CTP. Of these 22 underwent PET and 47 ICA/FFR. Obstructive CAD was defined as CTCA stenosis >50 % and CTP hypoperfusion, ICA stenosis >70 % or FFR <0.80. PET hyperaemic myocardial blood flow (MBF) was lower in obstructive than non-obstructive territories defined by ICA/FFR (1.76 (1.32-2.20) vs 3.11 (2.44-3.79) mL/(g/min), P < 0.001) and CTCA/CTP (1.76 (1.32-2.20) vs 3.12 (2.44-3.79) mL/(g/min), P < 0.001). Baseline and hyperaemic CT attenuation density was lower in obstructive than non-obstructive territories (73 (71-76) vs 86 (84-88) HU, P < 0.001 and 101 (96-106) vs 111 (107-114) HU, P 0.001). PET hyperaemic MBF corrected for rate pressure product correlated with CT attenuation density (r = 0.579, P < 0.001). There was excellent per-patient sensitivity (96 %), specificity (85 %), negative predictive value (90 %) and positive predictive value (94 %) for CTCA/CTP vs ICA/FFR. CT myocardial attenuation density correlates with {sup 15}O-water PET MBF. CTCA and CTP can accurately identify obstructive CAD. (orig.)

  18. Long residence times - bad tracer tests?

    Science.gov (United States)

    Ghergut, Julia; Behrens, Horst; Sauter, Martin

    2015-04-01

    Tracer tests conducted at geothermal well doublets or triplets in the Upper Rhine Rift Valley [1] all face, with very few exceptions so far, one common issue: lack of conclusive tracer test results, or tracer signals still undetectable for longer than one or two years after tracer injection. While the reasons for this surely differ from site to site (Riehen, Landau, Insheim, Bruchsal, ...), its effects on how the usefulness of tracer tests is perceived by the non-tracer community are pretty much the same. The 'poor-signal' frustration keeps nourishing two major 'alternative' endeavours : (I) design and execute tracer tests in single-well injection-withdrawal (push-pull), 'instead of' inter-well flow-path tracing configurations; (II) use 'novel' tracer substances instead of the 'old' ones which have 'obviously failed'. Frustration experienced with most inter-well tracer tests in the Upper Rhine Rift Valley has also made them be regarded as 'maybe useful for EGS' ('enhanced', or 'engineered' geothermal systems, whose fluid RTD typically include a major share of values below one year), but 'no longer worthwhile a follow-up sampling' in natural, large-scale hydrothermal reservoirs. We illustrate some of these arguments with the ongoing Bruchsal case [2]. The inter-well tracer test conducted at Bruchsal was (and still is!) aimed at assessing inter-well connectivity, fluid residence times, and characterizing the reservoir structure [3]. Fluid samples taken at the geothermal production well after reaching a fluid turnover of about 700,000 m3 showed tracer concentrations in the range of 10-8 Minj per m3, in the liquid phase of each sample (Minj being the total quantity of tracer injected as a short pulse at the geothermal re-injection well). Tracer signals might actually be higher, owing to tracer amounts co-precipitated and/or adsorbed onto the solid phase whose accumulation in the samples was unavoidable (due to pressure relief and degassing during the very sampling

  19. GTS-LCS, in-situ experiment 2. Modeling of tracer test 09-03

    International Nuclear Information System (INIS)

    Manette, M.; Saaltink, M.W.; Soler, J.M.

    2015-02-01

    Within the framework of the GTS-LCS project (Grimsel Test Site - Long-Term Cement Studies), an in-situ experiment lasting about 5 years was started in 2009 to study water-cement-rock interactions in a fractured granite. Prior to the experiment, a tracer test was performed to characterize the initial flow and transport properties of the rock around the experimental boreholes. This study reports on the model interpretation of tracer test 09-03. The calculations were performed by means of a two-dimensional model (homogeneous fracture plane including 3 boreholes) using the Retraso-CodeBright software package. In the tracer test, Grimsel groundwater containing the tracer (uranine) was circulated in the emplacement borehole during 43 days (zero injection flow rate). Circulation continued without tracer afterwards. Water was extracted at the observation and extraction boreholes. Results from a model sensitivity analysis comparing model results with measured tracer concentrations showed 3 cases where the evolution of tracer concentrations in the 3 different boreholes was satisfactory. In these cases a low-permeability skin affected the emplacement and observation boreholes. No skin appeared to affect the extraction borehole. The background hydraulic gradient seems to have no effect on the results of the tracer test. These results will be applied in the calculation of the initial flow field for the reactive transport phase of in-situ experiment 2 (interaction between pre-hardened cement and fractured granite at Grimsel). (orig.)

  20. System identification by experimental data processing, application to turbulent transport of a tracer in pipe flow

    International Nuclear Information System (INIS)

    Burgos, Manuel; Getto, Daniel; Berne, Philippe

    2005-01-01

    System identification is the first, and probably the most important step in detecting abnormal behavior, control system design or performance improving. Data analysis is performed for studying the plant behavior, sensitivity of operation procedures and several other goals. In all these cases, the observed data is the convolution of an input function, and the system's impulse response. Practical discrete time convolutions may be performed multiplying a matrix built from the impulse response by the input vector, but for deconvolution it is necessary to invert the matrix which is singular in a causal system. Another method for deconvolution is by means of Fourier Transforms. Actual readings are usually corrupted by noise and, besides, their transform shows high low frequencies components and high frequency ones mainly due to additive noise. Subjective decisions as cut-off frequency should be taken as well. This paper proposes a deconvolution method based on parameters fitting of suitable models, where they exist, and estimation of values where analytical forms are not available. It is based on the global, non linear fitting of them, with a maximum likelihood criteria. An application of the method is shown using data from two fluid flow experiments. The experimental test rigs basically consist in a long section of straight pipe in which fluid is flowing. A pulse of tracer is injected at the entrance and detected at various locations along the pipe. An attempt of deconvolution of signals from successive probes using a classical model describing the flow of tracer as a plug moving with the average fluid velocity, plus some axial dispersion. The parameters are for instance the velocity of the plug and a dispersion coefficient. After parameter fitting, the model is found to reproduce the experimental data well. The flow rates deduced from the adjusted travel times are in very good agreement with the actual values. In addition, the flow dispersion coefficient is obtained

  1. Dissipation of hydrological tracers and the herbicide S-metolachlor in batch and continuous-flow wetlands.

    Science.gov (United States)

    Maillard, Elodie; Lange, Jens; Schreiber, Steffi; Dollinger, Jeanne; Herbstritt, Barbara; Millet, Maurice; Imfeld, Gwenaël

    2016-02-01

    Pesticide dissipation in wetland systems with regard to hydrological conditions and operational modes is poorly known. Here, we investigated in artificial wetlands the impact of batch versus continuous-flow modes on the dissipation of the chiral herbicide S-metolachlor (S-MET) and hydrological tracers (bromide, uranine and sulforhodamine B). The wetlands received water contaminated with the commercial formulation Mercantor Gold(®) (960 g L(-1) of S-MET, 87% of the S-enantiomer). The tracer mass budget revealed that plant uptake, sorption, photo- and presumably biodegradation were prominent under batch mode (i.e. characterized by alternating oxic-anoxic conditions), in agreement with large dissipation of S-MET (90%) under batch mode. Degradation was the main dissipation pathway of S-MET in the wetlands. The degradate metolachlor oxanilic acid (MOXA) mainly formed under batch mode, whereas metolachlor ethanesulfonic acid (MESA) prevailed under continuous-flow mode, suggesting distinct degradation pathways in each wetland. R-enantiomer was preferentially degraded under batch mode, which indicated enantioselective biodegradation. The release of MESA and MOXA by the wetlands as well as the potential persistence of S-MET compared to R-MET under both oxic and anoxic conditions may be relevant for groundwater and ecotoxicological risk assessment. This study shows the effect of batch versus continuous modes on pollutant dissipation in wetlands, and that alternate biogeochemical conditions under batch mode enhance S-MET biodegradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A multiple-tracer approach to understanding regional groundwater flow in the Snake Valley area of the eastern Great Basin, USA

    International Nuclear Information System (INIS)

    Gardner, Philip M.; Heilweil, Victor M.

    2014-01-01

    Highlights: • Age tracers and noble gases constrain intra- and inter-basin groundwater flow. • Tritium indicates modern (<60 yr) recharge occurring in all mountain areas. • Noble-gas data identify an important interbasin hydraulic discontinuity. • Further groundwater development may significantly impact Snake Valley springs. - Abstract: Groundwater in Snake Valley and surrounding basins in the eastern Great Basin province of the western United States is being targeted for large-scale groundwater extraction and export. Concern about declining groundwater levels and spring flows in western Utah as a result of the proposed groundwater withdrawals has led to efforts that have improved the understanding of this regional groundwater flow system. In this study, environmental tracers (δ 2 H, δ 18 O, 3 H, 14 C, 3 He, 4 He, 20 Ne, 40 Ar, 84 Kr, and 129 Xe) and major ions from 142 sites were evaluated to investigate groundwater recharge and flow-path characteristics. With few exceptions, δ 2 H and δ 18 O show that most valley groundwater has similar ratios to mountain springs, indicating recharge is dominated by relatively high-altitude precipitation. The spatial distribution of 3 H, terrigenic helium ( 4 He terr ), and 3 H/ 3 He ages shows that modern groundwater (<60 yr) in valley aquifers is found only in the western third of the study area. Pleistocene and late-Holocene groundwater is found in the eastern parts of the study area. The age of Pleistocene groundwater is supported by minimum adjusted radiocarbon ages of up to 32 ka. Noble gas recharge temperatures (NGTs) are generally 1–11 °C in Snake and southern Spring Valleys and >11 °C to the east of Snake Valley and indicate a hydraulic discontinuity between Snake and Tule Valleys across the northern Confusion Range. The combination of NGTs and 4 He terr shows that the majority of Snake Valley groundwater discharges as springs, evapotranspiration, and well withdrawals within Snake Valley rather than

  3. Sodium bicarbonate-augmented stress thallium myocardial scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Sarin, Badal; Chugh, Pradeep Kumar; Kaushal, Dinesh; Soni, Nakse Lal; Sawroop, Kishan; Mondal, Anupam; Bhatnagar, Aseem [Department of Nuclear Medicine, Institute of Nuclear Medicine and Allied Sciences, Brig. S. K. Mazumdar Road, 110054, Delhi (India)

    2004-04-01

    It is well known that sodium bicarbonate in pharmacological doses induces transient alkalosis, causing intracellular transport of serum potassium. The aims of this study were (a) to investigate whether, in humans, myocardial thallium-201 uptake can be augmented by pretreatment with a single bolus of sodium bicarbonate at a pharmacological dose, (b) to verify general safety aspects of the intervention and (c) to evaluate the clinical implications of augmentation of {sup 201}Tl uptake, if any. Routine exercise myocardial scintigraphy was performed twice in eight adult volunteers (five normal and three abnormal), once without intervention and the second time (within a week) following intravenous administration of sodium bicarbonate (88 mEq in 50 ml) as a slow bolus 1 h prior to the injection of {sup 201}Tl. Conventional myocardial thallium study was compared with sodium bicarbonate interventional myocardial scintigraphy with respect to myocardial uptake (counts per minute per mCi injected dose), washout patterns in normal and abnormal myocardial segments, and overall clinical interpretation based on planar and single-photon emission tomographic (SPET) images. All patients remained asymptomatic after the intervention. A mean increase of 53% in myocardial uptake of thallium was noted in post-exercise acquisitions after the intervention, confirming uptake of the tracer via the potassium-hydrogen pump and its augmentation by transient alkalosis. The washout pattern remained unchanged. The visual quality of planar and SPET images improved significantly after the intervention. Out of the five abnormal myocardial segments identified in three cases, four showed significant filling-in after the intervention, causing the diagnosis to be upgraded from ''partial scar'' to ''ischaemia'', or from ''ischaemia'' to ''normal''. The overall scan impression changed in two out of three such cases. Sodium

  4. Estimation of water flow velocity in small plants using cold neutron imaging with D 2O tracer

    Science.gov (United States)

    Matsushima, U.; Herppich, W. B.; Kardjilov, N.; Graf, W.; Hilger, A.; Manke, I.

    2009-06-01

    Water flow imaging may help to better understand various problems related to water stress of plants. It may help to fully understand the water relations of plants. The objective of this research was to estimate the velocity of water flow in plant samples. Cut roses ( Rosa hybrida, var. 'Milva') were used as samples. Cold neutron radiography (CNR) was conducted at CONRAD, Helmholtz Center Berlin for Materials and Energy, Berlin, Germany. D 2O and H 2O were interchangeably injected into the water feeding system of the sample. After the uptake of D 2O, the neutron transmission increased due to the smaller attenuation coefficient of D 2O compared to H 2O. Replacement of D 2O in the rose peduncle was clearly observed. Three different optical flow algorithms, Block Matching, Horn-Schunck and Lucas-Kanade, were used to calculate the vector of D 2O tracer flow. The quality of sequential images providing sufficient spatial and temporal resolution allowed to estimate flow vector.

  5. Effects of ranolazine on ischemic threshold, coronary sinus blood flow, and myocardial metabolism in coronary artery disease.

    Science.gov (United States)

    Bagger, J P; Bøtker, H E; Thomassen, A; Nielsen, T T

    1997-07-01

    Cytoprotection or metabolic modulation is a new principle in the treatment of angina pectoris. The effect of ranolazine (a cytoprotective drug) on ischemic threshold, coronary sinus blood flow, and myocardial metabolism was evaluated by means of two pacing sequences in nine male patients with coronary artery disease (CAD) and in eight male controls. Ranolazine was given as an intravenous bolus followed by continuous infusion; the mean total dose was 32.7 mg and 31.7 mg in patients and controls, respectively. Angina pectoris was relieved in two patients after ranolazine but pacing time to pain was unchanged in the remaining patients. Maximal ST depression was lower (p = 0.02), but pacing time to maximal and to 1-mm ST depression remained unchanged after the drug. Ranolazine had no overall influence on coronary sinus blood flow, cardiac oxygen consumption, blood pressure, and heart rate. Cardiac uptake of free fatty acids (FFA) was reduced (p = 0.01), and net uptakes of glucose (p = 0.07) and lactate (p = 0.06) tended to be lower after ranolazine in CAD patients and controls. Ranolazine had no direct influence on cardiac exchange of glutamate, alanine, and citrate or on the arterial concentration of any metabolite. In the present study ranolazine had minimal clinical effects. A decrease in myocardial FFA utilization, however, allows greater myocardial glucose oxidation, which may increase the energy production in relation to oxygen availability.

  6. Evaluating 10B-enriched Boric Acid, Bromide, and Heat as Tracers of Recycled Groundwater Flow near MAR Operations

    Science.gov (United States)

    Becker, T.; Clark, J. F.

    2012-12-01

    Coupled with the unpredictability of a changing climate, the projected growth in human population over the next century requires new and innovative ways to augment already-depleted water supplies. An increasingly popular and promising development is managed aquifer recharge (MAR), a cost-effective method of intentionally storing potable water in groundwater aquifers at engineered sites worldwide. Reclaimed (or recycled) water, defined as cleaned and treated wastewater, will account for a larger portion of MAR water in future years. A crucial component for managing groundwater recharged with reclaimed water is its subsurface travel time. The California Department of Public Health (CDPH), with the most recent draft of regulations issued on November 21, 2011, requires the application of groundwater tracers to demonstrate subsurface residence time. Residence time increases the quality of reclaimed water via soil-aquifer treatment (SAT), which includes mechanisms such as sorption, biological degradation, and microbial inactivation to remove potential contaminants or pathogens. This study addresses the need for an appropriate tracer to determine groundwater residence times near MAR facilities. Standard shallow groundwater dating techniques, such as T/3He and chlorofluorocarbon (CFC) methods, cannot be used because their uncertainties are typically ± 2 years, longer than the target CDPH retention time of ~6 months. These methods also cannot map preferential flow paths. Sulfur hexafluoride (SF6), a nonreactive synthetic gas, is well-established as a deliberate tracer for determining subsurface travel time; however, SF6 is a very strong greenhouse gas and the California Air Resources Board (CARB) is regulating its emission. Other tracers, such as noble gas isotopes, that have successfully determined subsurface retention times are impractical due to their high cost. A multi-tracer experiment at the San Gabriel Spreading Grounds test basin (Montebello Forebay, Los Angeles

  7. Groundwater Flow Computed with Modflow and Isotopic Age Tracer Data in the Continental Intercalaire (Sahara)

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, J. O.; Goncalves, J.; Deschamps, P.; Hamelin, B. [Centre Europeen de Recherche et d' Enseignement de Geosciences de l' Environnement, Aix-en-Provence (France); Zouari, K. [Laboratoire de Radio-Analyses et Environnement, Sfax (Tunisia); Guendouz, A. [University of Blida, Science Engineering Faculty, Soummaa Blida (Algeria); Michelot, J. -L. [Interactions et Dynamique des Environnements de Surface, Universite Paris-Sud, Orsay (France)

    2013-07-15

    In one of the largest confined aquifers of the world, the Continental Intercalaire (Sahara), which is located in an arid region (57 mm/y of mean of precipitation), groundwater flow patterns are rather complex. Coupling measurements of isotopic composition of water and age mass calculations obtained by numerical simulations can allow, to a greater extent than a simple comparison, to constrain and validate the recharge scenario, transport and age of groundwater. First, the multiple tracers {sup 14}C, {sup 36}Cl, or {sup 234}U/{sup 238}U used in this study including noble gases such as {sup 4}He, allow investigation of a large range of groundwater ages. Then a MODFLOW simulation is built using (i) the distribution of hydrological parameters, (ii) geometrical limits and iii) the concept of age mass of water, accounting for the tracers data. This approach improves the understanding of the hydrodynamics of this system. In particular, the mixing of old and young waters should be better constrained and the interpretation of paleohydrological conditions is permitted. (author)

  8. Myocardial perfusion imaging with a cadmium zinc telluride-based gamma camera versus invasive fractional flow reserve

    Energy Technology Data Exchange (ETDEWEB)

    Mouden, Mohamed [Isala klinieken, Department of Cardiology, Zwolle (Netherlands); Isala klinieken, Department of Nuclear Medicine, Zwolle (Netherlands); Ottervanger, Jan Paul; Timmer, Jorik R. [Isala klinieken, Department of Cardiology, Zwolle (Netherlands); Knollema, Siert; Reiffers, Stoffer; Oostdijk, Ad H.J.; Jager, Pieter L. [Isala klinieken, Department of Nuclear Medicine, Zwolle (Netherlands); Boer, Menko-Jan de [University Medical Centre Nijmegen, Department of Cardiology, Nijmegen (Netherlands)

    2014-05-15

    Recently introduced ultrafast cardiac SPECT cameras with cadmium zinc telluride-based (CZT) detectors may provide superior image quality allowing faster acquisition with reduced radiation doses. Although the level of concordance between conventional SPECT and invasive fractional flow reserve (FFR) measurement has been studied, that between FFR and CZT-based SPECT is not yet known. Therefore, we aimed to assess the level of concordance between CZT SPECT and FFR in a large patient group with stable coronary artery disease. Both invasive FFR and myocardial perfusion imaging with a CZT-based SPECT camera, using Tc-tetrofosmin as tracer, were performed in 100 patients with stable angina and intermediate grade stenosis on invasive coronary angiography. A cut-off value of <0.75 was used to define abnormal FFR. The mean age of the patients was 64 ± 11 years, and 64 % were men. SPECT demonstrated ischaemia in 31 % of the patients, and 20 % had FFR <0.75. The concordance between CZT SPECT and FFR was 73 % on a per-patient basis and 79 % on a per-vessel basis. Discordant findings were more often seen in older patients and were mainly (19 %) the result of ischaemic SPECT findings in patients with FFR ≥0.75, whereas only 8 % had an abnormal FFR without ischaemia as demonstrated by CZT SPECT. Only 20 - 30 % of patients with intermediate coronary stenoses had significant ischaemia as assessed by CZT SPECT or invasive FFR. CZT SPECT showed a modest degree of concordance with FFR, which is comparable with previous results with conventional SPECT. Further investigations are particularly necessary in patients with normal SPECT and abnormal FFR, especially to determine whether these patients should undergo revascularization. (orig.)

  9. Characterization of a managed aquifer recharge system using multiple tracers.

    Science.gov (United States)

    Moeck, Christian; Radny, Dirk; Popp, Andrea; Brennwald, Matthias; Stoll, Sebastian; Auckenthaler, Adrian; Berg, Michael; Schirmer, Mario

    2017-12-31

    Knowledge about the residence times of artificially infiltrated water into an aquifer and the resulting flow paths is essential to developing groundwater-management schemes. To obtain this knowledge, a variety of tracers can be used to study residence times and gain information about subsurface processes. Although a variety of tracers exists, their interpretation can differ considerably due to subsurface heterogeneity, underlying assumptions, and sampling and analysis limitations. The current study systematically assesses information gained from seven different tracers during a pumping experiment at a site where drinking water is extracted from an aquifer close to contaminated areas and where groundwater is artificially recharged by infiltrating surface water. We demonstrate that the groundwater residence times estimated using dye and heat tracers are comparable when the thermal retardation for the heat tracer is considered. Furthermore, major ions, acesulfame, and stable isotopes (δ 2 H and δ 18 O) show that mixing of infiltrated water and groundwater coming from the regional flow path occurred and a vertical stratification of the flow system exist. Based on the concentration patterns of dissolved gases (He, Ar, Kr, N 2 , and O 2 ) and chlorinated solvents (e.g., tetrachloroethene), three temporal phases are observed in the ratio between infiltrated water and regional groundwater during the pumping experiment. Variability in this ratio is significantly related to changes in the pumping and infiltration rates. During constant pumping rates, more infiltrated water was extracted, which led to a higher dilution of the regional groundwater. An infiltration interruption caused however, the ratio to change and more regional groundwater is extracted, which led to an increase in all concentrations. The obtained results are discussed for each tracer considered and its strengths and limitations are illustrated. Overall, it is demonstrated that aquifer heterogeneity and

  10. Laboratory and numerical investigations of kinetic interface sensitive tracers transport for immiscible two-phase flow porous media systems

    Science.gov (United States)

    Tatomir, Alexandru Bogdan A. C.; Sauter, Martin

    2017-04-01

    A number of theoretical approaches estimating the interfacial area between two fluid phases are available (Schaffer et al.,2013). Kinetic interface sensitive (KIS) tracers are used to describe the evolution of fluid-fluid interfaces advancing in two phase porous media systems (Tatomir et al., 2015). Initially developed to offer answers about the supercritical (sc)CO2 plume movement and the efficiency of trapping in geological carbon storage reservoirs, KIS tracers are tested in dynamic controlled laboratory conditions. N-octane and water, analogue to a scCO2 - brine system, are used. The KIS tracer is dissolved in n-octane, which is injected as the non-wetting phase in a fully water saturated porous media column. The porous system is made up of spherical glass beads with sizes of 100-250 μm. Subsequently, the KIS tracer follows a hydrolysis reaction over the n-octane - water interface resulting in an acid and phenol which are both water soluble. The fluid-fluid interfacial area is described numerically with the help of constitutive-relationships derived from the Brooks-Corey model. The specific interfacial area is determined numerically from pore scale calculations, or from different literature sources making use of pore network model calculations (Joekar-Niasar et al., 2008). This research describes the design of the laboratory setup and compares the break-through curves obtained with the forward model and in the laboratory experiment. Furthermore, first results are shown in the attempt to validate the immiscible two phase flow reactive transport numerical model with dynamic laboratory column experiments. Keywords: Fluid-fluid interfacial area, KIS tracers, model validation, CCS, geological storage of CO2

  11. Assessment of myocardial blood flow and coronary flow reserve with positron emission tomography in ischemic heart disease: current state and future directions.

    Science.gov (United States)

    Al Badarin, Firas; Aljizeeri, Ahmed; Almasoudi, Fatimah; Al-Mallah, Mouaz H

    2017-07-01

    Positron emission tomography (PET) is a versatile imaging technology that allows assessment of myocardial perfusion, both at a spatially relative scale and also in absolute terms, thereby enabling noninvasive evaluation of myocardial blood flow (MBF) and coronary flow reserve (CFR). Assessment of MBF using FDA-approved PET isotopes, such as 82 Rb and 13 N-ammonia, has been well validated, and several software packages are currently available, thereby allowing for MBF evaluation to be incorporated into routine workflow in contemporary nuclear laboratories. Incremental diagnostic and prognostic information provided with the knowledge of MBF has the potential for widespread applications. Improving the ability to identify the true burden of obstructive epicardial coronary stenoses and allowing for noninvasive assessment of coronary micro circulatory function can be achieved with MBF assessment. On the other hand, attenuated CFR has been shown to predict adverse cardiovascular prognosis in a variety of clinical settings and patient subgroups. With expanding applications of MBF, this tool promises to provide unique insight into the integrity of the entire coronary vascular bed beyond what is currently available with relative perfusion assessment. This review intends to provide an in-depth discussion of technical and clinical aspects of MBF assessment with PET as it relates to patients with ischemic heart disease.

  12. Impaired coronary flow reserve is the most important marker of viable myocardium in the myocardial segment-based analysis of dual-isotope gated myocardial perfusion single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Lee, Won Woo; So, Young; Kim, Ki Bong; Lee, Dong Soo

    2014-01-01

    The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), 201 Tl perfusion status at rest, 201 Tl 24 hours redistribution and systolic wall thickening of 99m Tc-methoxyisobutylisonitrile using a dual isotope gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with coronary artery disease (CAD) who were re-vascularized with a coronary artery bypass graft (CABG) surgery. A total of 39 patients with CAD was enrolled (34 men and 5 women), aged between 36 and 72 years (mean 58 ± 8 standard in years) who underwent both pre- and 3 months post-CABG myocardial SPECT. We analyzed 17 myocardial segments per patient. Perfusion status and wall motion were semi-quantitatively evaluated using a 4-point grading system. Viable myocardium was defined as dysfunctional myocardium which showed wall motion improvement after CABG. The left ventricular ejection fraction (LVEF) significantly increased from 37.8 ± 9.0% to 45.5 ± 12.3% (p 201 Tl rest perfusion status (p = 0.024) were significant predictors of wall motion improvement. However, in multiple logistic regression analysis, stress/rest reversibility alone was a significant predictor for post-CABG wall motion improvement (p < 0.001). Stress/rest reversibility (impaired CFR) during dual-isotope gated myocardial perfusion SPECT was the single most important predictor of wall motion improvement after CABG.

  13. Evaluation of cellular viability by quantitative autoradiographic study of myocardial uptake of a fatty acid analogue in isoproterenol-induced focal rat heart necrosis

    International Nuclear Information System (INIS)

    Humbert, T.; Luu-Duc, C.; Comet, M.; Demenge, P.

    1991-01-01

    Previous studies led us to hypothesize that a fatty acid analogue, 15-p-iodophenyl-β-methyl pentadecanoic acid (IMPPA or BMIPP), which is taken up but not quickly metabolized by heart cells, would be a more suitable tracer of cellular viability that 201 Tl. Biodistribution studies of 1- 14 C-IMPPA in conscious, freely moving rats showed that the concentration ratio of radioactivity in the heart with respect to the blood was about 8 for at least 60 min after intravenous administration, permitting its use as a putative tracer in these conscious, freely moving rats. Thereafter, the myocardial uptake of 14 C-IMPPA was studied in isoproterenol-treated rats (daily treatment for 10 days in order to induce cardiac hypertrophy and necrotic foci) with respect to control ones. Comparison of myocardial localizations by quantitative autoradiography of the uptake of 201 Tl and 14 C-IMPPA with that of triphenyltetrazolium chloride (TTC) staining enabled comparative evaluation of nutritional blood flow, localization and uptake of 14 C-IMPPA and necrotic foci size. Distributions of 14 C-IMPPA and 201 Tl in control rats' hearts were homogenous, like TTC staining. In infarcted hearts, areas of decreased 14 C-IMPPA uptake were nearly the same (100%±5%) as those unstained by TTC. These areas were larger than those showing a decrease in thallium uptake (about 70%±5% of the total scar size). Therefore, IMPPA seems to be a more accurate and sensitive indicator of necrosis localization compared with thallium. It may be a useful agent for assessment of myocardial viability by single photon emission tomography (SPET) imaging. (orig.)

  14. The use of synthetic colloids in tracer transport experiments in saturated rock fractures

    International Nuclear Information System (INIS)

    Reimus, P.W.

    1995-08-01

    Studies of groundwater flow and contaminant transport in saturated, fractured geologic media are of great interest to researchers studying the potential long-term storage of hazardous wastes in or near such media. A popular technique for conducting such studies is to introduce tracers having different chemical and physical properties into a system and then observe the tracers at one or more downstream locations, inferring flow and transport mechanisms from the breakthrough characteristics of the different tracers. Many tracer studies have been conducted in saturated, fractured media to help develop and/or refine models capable of predicting contaminant transport over large scales in such media

  15. Tracers and Tracer Testing: Design, Implementation, Tracer Selection, and Interpretation Methods

    Energy Technology Data Exchange (ETDEWEB)

    G. Michael Shook; Shannon L.; Allan Wylie

    2004-01-01

    Conducting a successful tracer test requires adhering to a set of steps. The steps include identifying appropriate and achievable test goals, identifying tracers with the appropriate properties, and implementing the test as designed. When these steps are taken correctly, a host of tracer test analysis methods are available to the practitioner. This report discusses the individual steps required for a successful tracer test and presents methods for analysis. The report is an overview of tracer technology; the Suggested Reading section offers references to the specifics of test design and interpretation.

  16. Quantitative Myocardial Perfusion Imaging Versus Visual Analysis in Diagnosing Myocardial Ischemia: A CE-MARC Substudy.

    Science.gov (United States)

    Biglands, John D; Ibraheem, Montasir; Magee, Derek R; Radjenovic, Aleksandra; Plein, Sven; Greenwood, John P

    2018-05-01

    This study sought to compare the diagnostic accuracy of visual and quantitative analyses of myocardial perfusion cardiovascular magnetic resonance against a reference standard of quantitative coronary angiography. Visual analysis of perfusion cardiovascular magnetic resonance studies for assessing myocardial perfusion has been shown to have high diagnostic accuracy for coronary artery disease. However, only a few small studies have assessed the diagnostic accuracy of quantitative myocardial perfusion. This retrospective study included 128 patients randomly selected from the CE-MARC (Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease) study population such that the distribution of risk factors and disease status was proportionate to the full population. Visual analysis results of cardiovascular magnetic resonance perfusion images, by consensus of 2 expert readers, were taken from the original study reports. Quantitative myocardial blood flow estimates were obtained using Fermi-constrained deconvolution. The reference standard for myocardial ischemia was a quantitative coronary x-ray angiogram stenosis severity of ≥70% diameter in any coronary artery of >2 mm diameter, or ≥50% in the left main stem. Diagnostic performance was calculated using receiver-operating characteristic curve analysis. The area under the curve for visual analysis was 0.88 (95% confidence interval: 0.81 to 0.95) with a sensitivity of 81.0% (95% confidence interval: 69.1% to 92.8%) and specificity of 86.0% (95% confidence interval: 78.7% to 93.4%). For quantitative stress myocardial blood flow the area under the curve was 0.89 (95% confidence interval: 0.83 to 0.96) with a sensitivity of 87.5% (95% confidence interval: 77.3% to 97.7%) and specificity of 84.5% (95% confidence interval: 76.8% to 92.3%). There was no statistically significant difference between the diagnostic performance of quantitative and visual analyses (p = 0.72). Incorporating rest myocardial

  17. Application of myocardial perfusion quantitative imaging for the evaluation of therapeutic effect in canine with myocardial infarction

    International Nuclear Information System (INIS)

    Liang Hong; Chen Ju; Liu Sheng; Zeng Shiquan

    2000-01-01

    Myocardial blood perfusion (MBP) ECT and quantitative analysis were performed in 10 canines with experimental acute myocardial infarct (AMI). The accuracy of main myocardial quantitative index, including defect volume (DV) and defect fraction (DF), was estimated and correlated with histochemical staining (HS) of infarcted area. Other 21/AMI canines were divided into Nd:YAG laser trans-myocardial revascularization treated group LTMR and control group. All canines were performed MBP ECT after experimental AMI. Results found that the infarcted volume (IV) measured by HS has well correlated (r 0.88) with DV estimated by myocardial quantitative analysis. But the DF values calculated by both methods was not significantly different (t = 1.28 P > 0.05). In LTMR group 27.5% +- 3.9%, the DF is smaller than control group 32.1% +- 4.6% (t = 2.49 P 99m Tc-MIBI myocardial perfusion SPECT and quantitative study can accurately predict the myocardial blood flow and magnitude of injured myocardium. Nd:YAG LTMR could improve myocardial blood perfusion of ischemic myocardium and decrease effectively the infarct areas

  18. Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

    International Nuclear Information System (INIS)

    McCommis, Kyle S.; Goldstein, Thomas A.; Pilgram, Thomas; Abendschein, Dana R.; Misselwitz, Bernd; Gropler, Robert J.; Zheng, Jie

    2010-01-01

    To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and 99m Tc-labeled red blood cells were injected to obtain respective gold standards. Microsphere-measured MBF and 99m Tc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. (orig.)

  19. Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

    Science.gov (United States)

    McCommis, Kyle S.; Goldstein, Thomas A.; Abendschein, Dana R.; Misselwitz, Bernd; Pilgram, Thomas; Gropler, Robert J.

    2010-01-01

    Objective To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. Methods A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and 99mTc-labeled red blood cells were injected to obtain respective gold standards. Results Microsphere-measured MBF and 99mTc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. Conclusions MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. PMID:20182731

  20. Tracer tests Wairakei

    International Nuclear Information System (INIS)

    McCabe, W.J.; Manning, M.R.; Barry, B.J.

    1980-07-01

    The report summarises the radioactive tracer tests, using iodine-131 and bromine-82, made in the Wairakei geothermal field over the period 1978-80. Injection of tracer into three wells with strong cool water downflows at about 300-400m below ground level, produced strong rapid responses from the only deep wells feeding from about 800-1000m and lying in the south-westerly direction from the injection wells, i.e. parallel to the fault planes. Shallower wells, even though in some cases much closer to the injection well, reacted much more slowly. Velocities, as measured by peak arrival times, as high as 22m/h over 200m and 11m/h over 650m, were found. The flow patterns for the cool water feeds to the production area are discussed

  1. Simulation of variable-density flow and transport of reactive and nonreactive solutes during a tracer test at Cape Cod, Massachusetts

    Science.gov (United States)

    Zhang, Hubao; Schwartz, Frank W.; Wood, Warren W.; Garabedian, S.P.; LeBlanc, D.R.

    1998-01-01

    A multispecies numerical code was developed to simulate flow and mass transport with kinetic adsorption in variable-density flow systems. The two-dimensional code simulated the transport of bromide (Br−), a nonreactive tracer, and lithium (Li+), a reactive tracer, in a large-scale tracer test performed in a sand-and-gravel aquifer at Cape Cod, Massachusetts. A two-fraction kinetic adsorption model was implemented to simulate the interaction of Li+ with the aquifer solids. Initial estimates for some of the transport parameters were obtained from a nonlinear least squares curve-fitting procedure, where the breakthrough curves from column experiments were matched with one-dimensional theoretical models. The numerical code successfully simulated the basic characteristics of the two plumes in the tracer test. At early times the centers of mass of Br− and Li+ sank because the two plumes were closely coupled to the density-driven velocity field. At later times the rate of downward movement in the Br− plume due to gravity slowed significantly because of dilution by dispersion. The downward movement of the Li+ plume was negligible because the two plumes moved in locally different velocity regimes, where Li+ transport was retarded relative to Br−. The maximum extent of downward transport of the Li+ plume was less than that of the Br− plume. This study also found that at early times the downward movement of a plume created by a three-dimensional source could be much more extensive than the case with a two-dimensional source having the same cross-sectional area. The observed shape of the Br− plume at Cape Cod was simulated by adding two layers with different hydraulic conductivities at shallow depth across the region. The large dispersion and asymmetrical shape of the Li+ plume were simulated by including kinetic adsorption-desorption reactions.

  2. Climate proxy data as groundwater tracers in regional flow systems

    Science.gov (United States)

    Clark, J. F.; Morrissey, S. K.; Stute, M.

    2008-05-01

    The isotopic and chemical signatures of groundwater reflect local climate conditions. By systematically analyzing groundwater and determining their hydrologic setting, records of past climates can be constructed. Because of their chemistries and relatively uncomplicated source functions, dissolved noble gases have yielded reliable records of continental temperatures for the last 30,000 to 50,000 years. Variations in the stable isotope compositions of groundwater due to long term climate changes have also been documented over these time scales. Because glacial - interglacial climate changes are relatively well known, these climate proxies can be used as "stratigraphic" markers within flow systems and used to distinguish groundwaters that have recharged during the Holocene from those recharged during the last glacial period, important time scales for distinguishing regional and local flow systems in many aquifers. In southern Georgia, the climate proxy tracers were able to identify leakage from surface aquifers into the Upper Floridan aquifer in areas previously thought to be confined. In south Florida, the transition between Holocene and glacial signatures in the Upper Floridan aquifer occurs mid-way between the recharge area and Lake Okeechobee. Down gradient of the lake, the proxies are uniform, indicating recharge during the last glacial period. Furthermore, there is no evidence for leakage from the shallow aquifers into the Upper Floridan. In the Lower Floridan, the climate proxies indicate that the saline water entered the aquifer after sea level rose to its present level.

  3. Evaluation of modelling of the TRUE-1 radially converging and dipole tests with conservative tracers. The Aespoe task force on modelling of groundwater flow and transport of solutes. Tasks 4C and 4D

    International Nuclear Information System (INIS)

    Elert, M.

    1999-05-01

    The 'Aespoe task force on modelling of groundwater flow and transport of solutes' is a forum for the international organisations supporting the Aespoe HRL Project. The purpose of the Task Force is to interact in the area of conceptual and numerical modelling of groundwater flow and solute transport in fractured rock. Task 4 of the Aespoe Modelling Task Force consists of modelling exercises in support of the TRUE-1 tracer tests. In this report, the modelling work performed within Tasks 4C and 4D is evaluated, which comprised predictive modelling of the radially converging tracer tests and dipole tracer tests performed within the TRUE-1 tests using non-sorbing tracers. The tests were performed between packed off boreholes penetrating a water-conducting geological feature with a simple structure (Feature A). These tests are to a great extent preparatory steps for the subsequent tests with sorbing radioactive tracers. In Tasks 4E and 4F of the Aespoe Modelling Task Force predictive modelling of the sorbing tracer tests is performed. Eight modelling teams representing seven organisations have performed predictive modelling using different modelling approaches and models. The modelling groups were initially given data from the site characterisation and data on the experimental set-up of the tracer tests. Based on this information model predictions were performed of drawdown, tracer mass recovery and tracer breakthrough. The performed predictions shows that the concept of Feature A as a singular well-connected feature with limited connectivity to its surroundings is quite adequate for predictions of drawdown in boreholes and conservative tracer breakthrough. Reasonable estimates were obtained using relatively simple models. However, more elaborate models with calibration or conditioning of transmissivities and transport apertures are required for more accurate predictions. The general flow and transport processes are well understood, but the methodology to derive the

  4. Evaluation of modelling of the TRUE-1 radially converging and dipole tests with conservative tracers. The Aespoe task force on modelling of groundwater flow and transport of solutes. Tasks 4C and 4D

    Energy Technology Data Exchange (ETDEWEB)

    Elert, M. [Kemakta Konsult AB, Stockholm (Sweden)

    1999-05-01

    The `Aespoe task force on modelling of groundwater flow and transport of solutes` is a forum for the international organisations supporting the Aespoe HRL Project. The purpose of the Task Force is to interact in the area of conceptual and numerical modelling of groundwater flow and solute transport in fractured rock. Task 4 of the Aespoe Modelling Task Force consists of modelling exercises in support of the TRUE-1 tracer tests. In this report, the modelling work performed within Tasks 4C and 4D is evaluated, which comprised predictive modelling of the radially converging tracer tests and dipole tracer tests performed within the TRUE-1 tests using non-sorbing tracers. The tests were performed between packed off boreholes penetrating a water-conducting geological feature with a simple structure (Feature A). These tests are to a great extent preparatory steps for the subsequent tests with sorbing radioactive tracers. In Tasks 4E and 4F of the Aespoe Modelling Task Force predictive modelling of the sorbing tracer tests is performed. Eight modelling teams representing seven organisations have performed predictive modelling using different modelling approaches and models. The modelling groups were initially given data from the site characterisation and data on the experimental set-up of the tracer tests. Based on this information model predictions were performed of drawdown, tracer mass recovery and tracer breakthrough. The performed predictions shows that the concept of Feature A as a singular well-connected feature with limited connectivity to its surroundings is quite adequate for predictions of drawdown in boreholes and conservative tracer breakthrough. Reasonable estimates were obtained using relatively simple models. However, more elaborate models with calibration or conditioning of transmissivities and transport apertures are required for more accurate predictions. The general flow and transport processes are well understood, but the methodology to derive the

  5. Heat tracer methods

    Science.gov (United States)

    Healy, Richard W.; Scanlon, Bridget R.

    2010-01-01

    The flow of heat in the subsurface is closely linked to the movement of water (Ingebritsen et al., 2006). As such, heat has been used as a tracer in groundwater studies for more than 100 years (Anderson, 2005). As with chemical and isotopic tracers (Chapter 7), spatial or temporal trends in surface and subsurface temperatures can be used to infer rates of water movement. Temperature can be measured accurately, economically, at high frequencies, and without the need to obtain water samples, facts that make heat an attractive tracer. Temperature measurements made over space and time can be used to infer rates of recharge from a stream or other surface water body (Lapham, 1989; Stonestrom and Constantz, 2003); measurements can also be used to estimate rates of steady drainage through depth intervals within thick unsaturated zones (Constantz et al., 2003; Shan and Bodvarsson, 2004). Several thorough reviews of heat as a tracer in hydrologic studies have recently been published (Constantz et al., 2003; Stonestrom and Constantz, 2003; Anderson, 2005; Blasch et al., 2007; Constantz et al., 2008). This chapter summarizes heat-tracer approaches that have been used to estimate recharge.Some clarification in terminology is presented here to avoid confusion in descriptions of the various approaches that follow. Diffuse recharge is that which occurs more or less uniformly across large areas in response to precipitation, infiltration, and drainage through the unsaturated zone. Estimates of diffuse recharge determined using measured temperatures in the unsaturated zone are referred to as potential recharge because it is possible that not all of the water moving through the unsaturated zone will recharge the aquifer; some may be lost to the atmosphere by evaporation or plant transpiration. Estimated fluxes across confining units in the saturated zone are referred to as interaquifer flow (Chapter 1). Focused recharge is that which occurs directly from a point or line source, such

  6. Effects of Insulin Resistance on Myocardial Blood Flow and Arterial Peripheral Circulation in Patients with Polycystic Ovary Syndrome.

    Science.gov (United States)

    Aldrighi, José M; Tsutsui, Jeane M; Kowastch, Ingrid; Ribeiro, Alessandra L; Scapinelli, Alessandro; Tamanaha, Sonia; Oliveira, Ricardo M; Mathias, Wilson

    2015-08-01

    Polycystic ovary syndrome (PCOS) is associated with increased risk for cardiovascular disease. We sought to evaluate the effects of insulin resistance (IR) on myocardial microcirculation and peripheral artery function in patients with PCOS. We studied 55 women (28 with PCOS without IR, 18 with PCOS and IR and 11 normal controls) who underwent laboratorial analysis, high-resolution vascular ultrasound and real time myocardial contrast echocardiography (RTMCE). Intima-media thickness (IMT) and brachial artery flow-mediated dilation (FMD) were evaluated by vascular ultrasound. The replenishment velocity (β), plateau of acoustic intensity (A) and myocardial blood flow reserve (MBFR) were determined by quantitative dipyridamole stress RTMCE. β reserve in group PCOS + IR was lower than control (2.34 ± 0.55 vs. 3.60 ± 0.6; P PCOS without IR (2.34 ± 0.55 vs. 3.17 ± 0.65; P PCOS without IR did not differ from those of control (4.59 ± 1.59 vs. 5.30 ± 1.64; P = 0.22) or from patients with PCOS + IR (4.59 ± 1.59 vs. 3.70 ± 1.47; P = 0.07). When comparing with control group, patients with PCOS + IR had lower MBFR (5.30 ± 1.64 vs. 3.70 ± 1.47; P = 0.01). No significant differences were found between control, PCOS without IR and PCOS + IR for FMD (0.18 ± 0.05, 0.15 ± 0.04 and 0.13 ± 0.07; P =NS) or IMT (0.48 ± 0.05, 0.47 ± 0.05 and 0.49 ± 0.07; P = NS). Women with PCOS and IR had depressed β and MBFR as demonstrated by quantitative RTMCE, but no alteration in endothelial dysfunction or IMT. PCOS without IR showed isolated depression in β reserve, probably an earlier marker of myocardial flow abnormality. © 2014, Wiley Periodicals, Inc.

  7. Unit vent airflow measurements using a tracer gas technique

    Energy Technology Data Exchange (ETDEWEB)

    Adams, D.G. [Union Electric Company, Fulton, MO (United States); Lagus, P.L. [Lagus Applied Technology, Inc., San Diego, CA (United States); Fleming, K.M. [NCS Corp., Columbus, OH (United States)

    1997-08-01

    An alternative method for assessing flowrates that does not depend on point measurements of air flow velocity is the constant tracer injection technique. In this method one injects a tracer gas at a constant rate into a duct and measures the resulting concentration downstream of the injection point. A simple equation derived from the conservation of mass allows calculation of the flowrate at the point of injection. Flowrate data obtained using both a pitot tube and a flow measuring station were compared with tracer gas flowrate measurements in the unit vent duct at the Callaway Nuclear Station during late 1995 and early 1996. These data are presented and discussed with an eye toward obtaining precise flowrate data for release rate calculations. The advantages and disadvantages of the technique are also described. In those test situations for which many flowrate combinations are required, or in large area ducts, a tracer flowrate determination requires fewer man-hours than does a conventional traverse-based technique and does not require knowledge of the duct area. 6 refs., 10 figs., 6 tabs.

  8. In vivo study of myocardial elastography under graded ischemia conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wei-Ning; Provost, Jean; Konofagou, Elisa E [Department of Biomedical Engineering, Columbia University, New York, NY (United States); Fujikura, Kana [Department of Radiology, Columbia University, New York, NY (United States); Wang Jie, E-mail: ek2191@columbia.edu [Department of Medicine, Columbia University, New York, NY (United States)

    2011-02-21

    The capability of currently available echocardiography-based strain estimation techniques to fully map myocardial abnormality at early stages of myocardial ischemia is yet to be investigated. In this study, myocardial elastography (ME), a radio-frequency (RF)-based strain imaging technique that maps the full 2D transmural angle-independent strain tensor in standard echocardiographic views at both high spatial and temporal resolution is presented. The objectives were to (1) evaluate the performance of ME on mapping the onset, extent and progression of myocardial ischemia at graded coronary constriction levels (from partial to complete coronary flow reduction), and (2) validate the accuracy of the strain estimates against sonomicrometry (SM) measurements. A non-survival canine ischemic model (n = 5) was performed by gradually constricting the left anterior descending (LAD) coronary blood flow from 0% (baseline blood flow) to 100% (zero blood flow) at 20% increments. An open-architecture ultrasound system was used to acquire RF echocardiograms in a standard full short-axis view at the frame rate of 211 fps, at least twice higher than what is typically used in conventional echocardiographic systems, using a previously developed, fully automated composite technique. Myocardial deformation was estimated by ME and validated against sonomicrometry. ME estimates and maps transmural (1) 2D displacements using RF cross-correlation and recorrelation; and (2) 2D polar (radial and circumferential) strains, derived from 2D (i.e. both lateral and axial) displacement components, at high accuracy. Full-view strain images were shown and found to reliably depict decreased myocardial function in the region at risk at increased levels of coronary flow reduction. The ME radial strain was deemed to be a more sensitive, quantitative, regional measure of myocardial ischemia as a result of coronary flow reduction when compared to the conventional wall motion score index and ejection fraction

  9. Tumor necrosis factor-alpha increases myocardial microvascular transport in vivo

    DEFF Research Database (Denmark)

    Hansen, P R; Svendsen, Jesper Hastrup; Høyer, S

    1994-01-01

    Tumor necrosis factor-alpha (TNF-alpha) is a primary mediator in the pathogenesis of tissue injury, and high circulating levels of TNF-alpha are found in a variety of pathological conditions. In open-chest anesthetized dogs, the effects of intracoronary recombinant human TNF-alpha (rTNF-alpha; 100...... in cardiac output and was associated with the appearance of areas with myocardial necrosis in the regional left ventricular wall. The myocardial plasma flow rate and maximum plasma flow rate in response to a 30-s coronary occlusion were not influenced by rTNF-alpha, although a decrease in the myocardial...... ng/kg for 60 min) on myocardial microvascular transport of a small hydrophilic indicator was examined by the single-injection, residue-detection method. Intracoronary infusion of rTNF-alpha increased myocardial microvascular transport after 120 min. This increase was preceded by a sustained decline...

  10. Iodine-123-labeled meta-iodobenzylguanidine myocardial scintigraphy evaluation of Machado-Joseph disease

    International Nuclear Information System (INIS)

    Kazuta, Toshinari; Hayashi, Michiyuki; Yoshita, Mitsuhiro; Hirai, Shunsaku

    1998-01-01

    Iodine-123-labeled meta-iodobenzylguanidine (( 123 I)MIBG), an analogue of guanetidine, is used as a tracer for evaluation of the function of sympathetic neurons. To investigate cardiac sympathetic function in Machado-Joseph disease (MJD), ( 123 I)MIBG myocardial scintigraphy was performed in 12 patients with MJD and 20 controls. In planar imaging studies, the heart to the mediastinum of the average count ratio (H/M) was calculated for both early and delayed images. The mean values of H/M in delayed images of MJD was lower than those of controls (p 123 I)MIBG myocardial scintigraphy in MJD can be seen earlier than abnormal sudomotor system detected by SSR. (author)

  11. Discrete fracture modelling for the Stripa tracer validation experiment predictions

    International Nuclear Information System (INIS)

    Dershowitz, W.; Wallmann, P.

    1992-02-01

    Groundwater flow and transport through three-dimensional networks of discrete fractures was modeled to predict the recovery of tracer from tracer injection experiments conducted during phase 3 of the Stripa site characterization and validation protect. Predictions were made on the basis of an updated version of the site scale discrete fracture conceptual model used for flow predictions and preliminary transport modelling. In this model, individual fractures were treated as stochastic features described by probability distributions of geometric and hydrologic properties. Fractures were divided into three populations: Fractures in fracture zones near the drift, non-fracture zone fractures within 31 m of the drift, and fractures in fracture zones over 31 meters from the drift axis. Fractures outside fracture zones are not modelled beyond 31 meters from the drift axis. Transport predictions were produced using the FracMan discrete fracture modelling package for each of five tracer experiments. Output was produced in the seven formats specified by the Stripa task force on fracture flow modelling. (au)

  12. Nitrate administration increases blood flow in dysfunctional but viable myocardium, leading to improved assessment of myocardial viability : A PET study

    NARCIS (Netherlands)

    Slart, Riemer H. J. A.; Agool, Ali; van Veldhuisen, Dirk J.; Dierckx, Rudi A.; Bax, Jeroen J.

    SPECT with Tc-99m-labeled agents is better able to detect viability after nitrate administration. Nitrates induce vasoclilation and may increase blood flow to severely hypoperfused but viable myocardium, thereby enhancing tracer delivery and improving the detection of viability. Quantitative data on

  13. [Myocardial imaging in acute myocardial infarction using beta-methyl-p-(123I)-iodophenylpentadecanoic acid: comparison with 201Tl imaging and wall motion].

    Science.gov (United States)

    Naruse, H; Itano, M; Kondo, T; Kogame, T; Yamamoto, J; Morita, M; Kawamoto, H; Fukutake, N; Ohyanagi, M; Iwasaki, T

    1992-01-01

    Myocardial imaging using beta-methyl-p-(123I)-iodophenylpentadecanoic acid (BMIPP) was performed in 11 patients with acute myocardial infarction. The left ventricular images were divided into 12 segments, and myocardial imagings with BMIPP were compared with coronary angiography (CAG), thallium-201 myocardial scintigraphy (TL) and wall motion obtained by two-dimensional echocardiography (WM). When the culprit lesion was at the proximal point of the left anterior descending artery (LAD), all segments showed depressed uptake. In 3 cases with single vessel disease of the LAD, inferior wall of the basis showed reduced uptake of BMIPP despite the location of the culprit lesion. In cases with discordant uptake between the two tracers, BMIPP frequently showed more severely depressed uptake than TL in the subacute phase, although the uptake of BMIPP correlated with that of TL (tau = 0.82, p less than 0.001). In such cases, the discordance was related to the improvement in WM from the acute phase to the convalescent phase. BMIPP uptake correlated with WM in the subacute phase (tau = 0.50, p less than 0.001). BMIPP showed more severely depressed uptake while WM showed mild asynergy in most cases in which discordance was found between the BMIPP and WM findings. However, there was no correlation between the change in WM from the acute to subacute phases, or the uptakes of BMIPP and TL alone. We concluded that the myocardial condition can be evaluated in detail in acute myocardial infarction by comparing the findings of BMIPP with those of TL and WM.

  14. Assessment of endothelial function and myocardial flow reserve using 15O-water PET without attenuation correction

    International Nuclear Information System (INIS)

    Tuffier, Stephane; Joubert, Michael; Bailliez, Alban; Legallois, Damien; Belin, Annette; Redonnet, Michel; Agostini, Denis; Manrique, Alain

    2016-01-01

    Myocardial blood flow (MBF) measurement using positron emission tomography (PET) from the washout rate of 15 O-water is theoretically independent of tissue attenuation. The aim of this study was to evaluate the impact of not using attenuation correction in the assessment of coronary endothelial function and myocardial flow reserve (MFR) using 15 O-water PET. We retrospectively processed 70 consecutive 15 O-water PET examinations obtained at rest and during cold pressor testing (CPT) in patients with dilated cardiomyopathy (n = 58), or at rest and during adenosine infusion in heart transplant recipients (n = 12). Data were reconstructed with attenuation correction (AC) and without attenuation correction (NAC) using filtered backprojection, and MBF was quantified using a single compartmental model. The agreement between AC and NAC data was assessed using Lin's concordance correlation coefficient followed by Bland-Altman plot analysis. Regarding endothelial function, NAC PET showed poor reproducibility and poor agreement with AC PET data. Conversely, NAC PET demonstrated high reproducibility and a strong agreement with AC PET for the assessment of MFR. Non-attenuation-corrected 15 O-water PET provided an accurate measurement of MFR compared to attenuation-corrected PET. However, non-attenuation-corrected PET data were less effective for the assessment of endothelial function using CPT in this population. (orig.)

  15. Current status and prospects of cardiac PET

    International Nuclear Information System (INIS)

    Yoshida, Katuya

    1999-01-01

    With positron emission tomography (PET), noninvasive measurements of myocardial blood flow and metabolism have now become possible. 1) Myocardial blood flow: We developed a high-resolution PET system for rabbits and showed that myocardial N-13 ammonnia uptake correlated well with flow measure with microspheres. We also demonstrated that a simplified PET protocol using N-13 ammonia or Rb-82 provide noninvasive measurement of coronary flow reserve in dog experiments. This protocol enables to produce estimates of myocardial blood flow in man and that are well correlated with the complex compartment model. 2) Myocardial glucose metabolism: We validated experimentally a simple method to quantify tissue glucose utilization with the brain reference index (BRI) using C-14 deoxyglucose and assessed its clinical feasibility for myocardial PET. 3) Membrane integrity: Loss of cell membrane integrity for trapping the potassium or it's analog is a market of myocardial necrosis/viability. We recently synthetized potassium-38 as a PET tracer and started an experimental study. (author)

  16. Tl myocardial SPECT demonstrates importance of collateral circulation in patients with myocardial infarction

    International Nuclear Information System (INIS)

    Hattori, Fukunori

    1997-01-01

    The influence of collateral circulation on the preservation of myocardial viability and the efficacy of drug therapy and PTCA were evaluated by exercise 201 Tl myocardial SPECT before and after treatment. Thirty-five patients with a history of myocardial infarction resulting from total or subtotal obstruction of the responsible coronary artery were divided into four groups, according to the method of the treatment and the degree of collateral blood flow. Patients in groups A and B received drug therapy and displayed developed and undeveloped collateral circulation, respectively. Groups C and D received PTCA and displayed developed and undeveloped collateral circulation, respectively. Tl myocardial SPECT was performed before treatment to record the extent of redistribution to the occluded region, the degree of myocardial viability and the nature and extent of the ischemic lesion. In group A, myocardial perfusion improved, although redistribution remained in all cases, while in group B, 4 of 7 cases improved after drug therapy. In group C, myocardial perfusion improved in all cases, and redistribution disappeared in 7 of 12 cases. 5 of 6 cases improved in group D after PTCA. After drug therapy, the %Tl uptake in the infarcted region improved significantly in initial and delayed images of patients in group A. The differences in initial and delayed images in group B before and after drug therapy were not significant. In contrast, groups C and D both registered significant improvement in initial and delayed images after PTCA. The washout rate improved significantly in groups A, C and D after their respective treatments. These results suggest that developed collateral circulation helps to preserve myocardial viability in cases of myocardial infarction. Myocardial perfusion improved after drug therapy in cases with developed collateral circulation, and in patients with developed and undeveloped collateral circulation receiving PTCA. (K.H.)

  17. Myocardial blood flow quantification by Rb-82 cardiac PET/CT: A detailed reproducibility study between two semi-automatic analysis programs.

    OpenAIRE

    Dunet, V.; Klein, R.; Allenbach, G.; Renaud, J.; deKemp, R.A.; Prior, J.O.

    2016-01-01

    Background Several analysis software packages for myocardial blood flow (MBF) quantification from cardiac PET studies exist, but they have not been compared using concordance analysis, which can characterize precision and bias separately. Reproducible measurements are needed for quantification to fully develop its clinical potential. Methods Fifty-one patients underwent dynamic Rb-82 PET at rest and during adenosine stress. Data were processed with PMOD and FlowQuant (Lortie model). MBF and m...

  18. Impact of Admission Blood Glucose on Coronary Collateral Flow in Patients with ST-Elevation Myocardial Infarction.

    Science.gov (United States)

    Kurmus, Ozge; Aslan, Turgay; Ekici, Berkay; Baglan Uzunget, Sezen; Karaarslan, Sukru; Tanindi, Asli; Erkan, Aycan Fahri; Akgul Ercan, Ebru; Kervancıoglu, Celal

    2018-01-01

    In patients with acute myocardial infarction, glucose metabolism is altered and acute hyperglycemia on admission is common regardless of diabetes status. The development of coronary collateral is heterogeneous among individuals with coronary artery disease. In this study, we aimed to investigate whether glucose value on admission is associated with collateral flow in ST-elevation myocardial infarction (STEMI) patients. We retrospectively evaluated 190 consecutive patients with a diagnosis of first STEMI within 12 hours of onset of chest pain. Coronary collateral development was graded according to Rentrop classification. Rentrop 0-1 was graded as poor collateral development, and Rentrop 2-3 was graded as good collateral development. Admission glucose was measured and compared between two groups. Mean admission glucose level was 173.0 ± 80.1 mg/dl in study population. Forty-five (23.7%) patients had good collateral development, and 145 (76.3%) patients had poor collateral development. There were no statistically significant differences in demographic characteristics between two groups. Three-vessel disease was more common in patients with good collateral development ( p =0.026). Mean admission glucose level was higher in patients with poor collateral than good collateral (180.6 ± 84.9 mg/dl versus 148.7 ± 56.6 mg/dl, resp., p =0.008). In univariate analysis, higher admission glucose was associated with poor collateral development, but multivariate logistic regression analysis revealed a borderline result (odds ratio 0.994, 95% CI 0.989-1.000, p =0.049). Our results suggest that elevated glucose on admission may have a role in the attenuation of coronary collateral blood flow in acute myocardial infarction. Further studies are needed to validate our results.

  19. A New Kind of Single-Well Tracer Test for Assessing Subsurface Heterogeneity

    Science.gov (United States)

    Hansen, S. K.; Vesselinov, V. V.; Lu, Z.; Reimus, P. W.; Katzman, D.

    2017-12-01

    Single-well injection-withdrawal (SWIW) tracer tests have historically been interpreted using the idealized assumption of tracer path reversibility (i.e., negligible background flow), with background flow due to natural hydraulic gradient being an un-modeled confounding factor. However, we have recently discovered that it is possible to use background flow to our advantage to extract additional information about the subsurface. To wit: we have developed a new kind of single-well tracer test that exploits flow due to natural gradient to estimate the variance of the log hydraulic conductivity field of a heterogeneous aquifer. The test methodology involves injection under forced gradient and withdrawal under natural gradient, and makes use of a relationship, discovered using a large-scale Monte Carlo study and machine learning techniques, between power law breakthrough curve tail exponent and log-hydraulic conductivity variance. We will discuss how we performed the computational study and derived this relationship and then show an application example in which our new single-well tracer test interpretation scheme was applied to estimation of heterogeneity of a formation at the chromium contamination site at Los Alamos National Laboratory. Detailed core hole records exist at the same site, from which it was possible to estimate the log hydraulic conductivity variance using a Kozeny-Carman relation. The variances estimated using our new tracer test methodology and estimated by direct inspection of core were nearly identical, corroborating the new methodology. Assessment of aquifer heterogeneity is of critical importance to deployment of amendments associated with in-situ remediation strategies, since permeability contrasts potentially reduce the interaction between amendment and contaminant. Our new tracer test provides an easy way to obtain this information.

  20. Quantitative aspects of myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Vogel, R.A.

    1980-01-01

    Myocardial perfusion measurements have traditionally been performed in a quantitative fashion using application of the Sapirstein, Fick, Kety-Schmidt, or compartmental analysis principles. Although global myocardial blood flow measurements have not proven clinically useful, regional determinations have substantially advanced our understanding of and ability to detect myocardial ischemia. With the introduction of thallium-201, such studies have become widely available, although these have generally undergone qualitative evaluation. Using computer-digitized data, several methods for the quantification of myocardial perfusion images have been introduced. These include orthogonal and polar coordinate systems and anatomically oriented region of interest segmentation. Statistical ranges of normal and time-activity analyses have been applied to these data, resulting in objective and reproducible means of data evaluation

  1. Evaluation of modelling of the TRUE-1 radially converging tests with sorbing tracers. The Aespoe task force on modelling of groundwater flow and transport of solutes. Tasks 4E and 4F

    Energy Technology Data Exchange (ETDEWEB)

    Elert, M.; Svensson, Haakan [Kemakta Konsult AB, Stockholm (Sweden)

    2001-05-01

    The Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes is a forum for the international organisations supporting the Aespoe HRL Project. The purpose of the Task Force is to interact in the area of conceptual and numerical modelling of groundwater flow and solute transport in fractured rock. Task 4 of the Aespoe Modelling Task Force consists of modelling exercises in support of the TRUE-1 tracer tests. In this report, the modelling work performed within Tasks 4E and 4F is evaluated, which comprised predictive modelling of the tracer tests (STT-1, STT-1b and STT-2) performed within the TRUE-1 project using sorbing and non-sorbing tracers. The tests were made between packed off boreholes penetrating a water-conducting geological feature with a simple structure (Feature A). Nine modelling teams representing eight organisations have performed predictive modelling of the tracer tests using different modelling approaches and models. The modelling groups were initially given data from the site characterisation, data from preliminary tracer tests performed with non-sorbing tracers and data on the experimental set-up of the sorbing tracer tests. Based on this information, model predictions were made of drawdown, tracer mass recovery and tracer breakthrough. For the predictions of the STT-1b and STT-2 tests results from previous tracer tests with sorbing tracer were also available. The predictions of the sorbing tracer breakthrough in the initial tracer test (STT-1) generally underestimated the breakthrough time, suggesting the need to include additional processes and evaluate the application of the laboratory data. As a result of model calibration and modification the predictions were considerably improved for the latter tracer tests (STT-1b and STT-2). Task 4E and 4F have proved to be very valuable in increasing the understanding of non-sorbing tracer transport in fractured rock. There is a general consensus on the major processes responsible for

  2. Determination of dispersion coefficients and average flow velocities in rivers radioactive tracers

    International Nuclear Information System (INIS)

    Carvalho, M.A.G. de; Moreira, R.M.

    1984-01-01

    The determination of the dispersion characteristics and residence time distribution in a series of adjoining stretches of a river with one single tracer injection, are presented. The method allows minimizing the amount of work and tracer expenditure in the measurement of fluvial transport over long or heterogeneous river courses. (M.A.C.) [pt

  3. A tracer investigation of the atmospheric dispersion in the Dyrnaes Valley, Greenland

    International Nuclear Information System (INIS)

    Gryning, S.-E.; Lyck, E.

    1983-02-01

    Mining at Kvanefjeld, Greenland, will result in releases of air pollution gases. In order to measure the dilution of these gases tracer experiments were carried out in July-August 1981. Results from these experiments are described. The Kvanefjeld constitutes the northwestern side of a valley. The tracer was released at the Kvanefjeld during the night and sampled in the valley. The measured tracer concentrations were compared with those calculated by use of a conventional model of the dispersion of plumes. The dilution of the tracer was found to correspond to the dilution at ground level of a plume from a stack of 100-200 m height in atmospheric neutral conditions (wind speed 5 m/s). General aspects of the flow-field in the valley are discussed. It was observed that the flow direction in the valley shifts between downvalley and upvalley with a period of approximately 1 hour. It is suggested that this behaviour is caused by the interplay of a drainage flow and a sea-breeze. (author)

  4. Effect of beam hardening on transmural myocardial perfusion quantification in myocardial CT imaging

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Levi, Jacob; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    The detection of subendocardial ischemia exhibiting an abnormal transmural perfusion gradient (TPG) may help identify ischemic conditions due to micro-vascular dysfunction. We evaluated the effect of beam hardening (BH) artifacts on TPG quantification using myocardial CT perfusion (CTP). We used a prototype spectral detector CT scanner (Philips Healthcare) to acquire dynamic myocardial CTP scans in a porcine ischemia model with partial occlusion of the left anterior descending (LAD) coronary artery guided by pressure wire-derived fractional flow reserve (FFR) measurements. Conventional 120 kVp and 70 keV projection-based mono-energetic images were reconstructed from the same projection data and used to compute myocardial blood flow (MBF) using the Johnson-Wilson model. Under moderate LAD occlusion (FFR~0.7), we used three 5 mm short axis slices and divided the myocardium into three LAD segments and three remote segments. For each slice and each segment, we characterized TPG as the mean "endo-to-epi" transmural flow ratio (TFR). BH-induced hypoenhancement on the ischemic anterior wall at 120 kVp resulted in significantly lower mean TFR value as compared to the 70 keV TFR value (0.29+/-0.01 vs. 0.55+/-0.01 pvalues on segments moderately affected or unaffected by BH. In the entire ischemic LAD territory, 120 kVp mean endocardial flow was significantly reduced as compared to mean epicardial flow (15.80+/-10.98 vs. 40.85+/-23.44 ml/min/100g; p<1e-04). At 70 keV, BH was effectively minimized resulting in mean endocardial MBF of 40.85+/-15.3407 ml/min/100g vs. 74.09+/-5.07 ml/min/100g (p=0.0054) in the epicardium. We also found that BH artifact in the conventional 120 kVp images resulted in falsely reduced MBF measurements even under non-ischemic conditions.

  5. Myocardial thallium-201 kinetics in normal and ischemic myocardium

    International Nuclear Information System (INIS)

    Grunwald, A.M.; Watson, D.D.; Holzgrefe, H.H. Jr.; Irving, J.F.; Beller, G.A.

    1981-01-01

    The net myocardial accumulation of thallium-201 after injection depends upon the net balance between continuing myocardial extraction from low levels of recirculating thallium in the blood compartment and the net rate of efflux of thallium from the myocardium into the extracardiac blood pool. These experiments were designed to measure separately the myocardial extraction and intrinsic myocardial efflux of thallium-201 at normal and at reduced rates of myocardial blood flow. The average myocardial extraction fraction at normal blood flow in 10 anesthetized dogs was 82 +/- 6% (+/- SD) at normal coronary arterial perfusion pressures and increased insignificantly, to 85 +/- 7%, at coronary perfusion pressures of 10--35 mm Hg. At normal coronary arterial perfusion pressures in 12 additional dogs, the intrinsic thallium washout in the absence of systemic recirculation had a half-time (T 1/2) of 54 +/- 7 minutes. The intrinsic cellular washout rate began to increase as distal perfusion pressures fell below 60 mm Hg and increased markedly to a T 1/2 of 300 minutes at perfusion pressures of 25--30 mm Hg. A second, more rapid component of intrinsic thallium washout (T 1/2 2.5 minutes) representing approximately 7% of the total initially extracted myocardial thallium was observed. The faster washout component is presumed to be due to washout of interstitial thallium unextracted by myocardial cells, whereas the slower component is presumed due to intracellular washout. The net clearance time of thallium measured after i.v. injection is much longer than the intrinsic myocardial cellular washout rate because of continuous replacement of myocardial thallium from systemic recirculation. Myocardial redistribution of thallium-201 in states of chronically reduced perfusion cannot be the result of increased myocardial extraction efficiency, but rather, is the result of the slower intrinsic cellular washout rate at reduced perfusion levels

  6. Positron emission computed tomography

    International Nuclear Information System (INIS)

    Grover, M.; Schelbert, H.R.

    1985-01-01

    Regional mycardial blood flow and substrate metabolism can be non-invasively evaluated and quantified with positron emission computed tomography (Positron-CT). Tracers of exogenous glucose utilization and fatty acid metabolism are available and have been extensively tested. Specific tracer kinetic models have been developed or are being tested so that glucose and fatty acid metabolism can be measured quantitatively by Positron-CT. Tracers of amino acid and oxygen metabolism are utilized in Positron-CT studies of the brain and development of such tracers for cardiac studies are in progress. Methods to quantify regional myocardial blood flow are also being developed. Previous studies have demonstrated the ability of Positron-/CT to document myocardial infarction. Experimental and clinical studies have begun to identify metabolic markers of reversibly ischemic myocardium. The potential of Positron-CT to reliably detect potentially salvageable myocardium and, hence, to identify appropriate therapeutic interventions is one of the most exciting applications of the technique

  7. Using Tracer Technology to Characterize Contaminated Pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Maresca, Joseph, W., Jr., Ph.D.; Bratton, Wesley, L., Ph.D., P.E.; Dickerson, Wilhelmina; Hales, Rochelle

    2005-12-30

    The Pipeline Characterization Using Tracers (PCUT) technique uses conservative and partitioning, reactive or other interactive tracers to remotely determine the amount of contaminant within a run of piping or ductwork. The PCUT system was motivated by a method that has been successfully used to characterize subsurface soil contaminants and is similar in operation to that of a gas chromatography column. By injecting a ?slug? of both conservative and partitioning tracers at one end (or section) of the piping and measuring the time history of the concentration of the tracers at the other end (or another section) of the pipe, the presence, location, and amount of contaminant within the pipe or duct can be determined. The tracers are transported along the pipe or duct by a gas flow field, typically air or nitrogen, which has a velocity that is slow enough so that the partitioning tracer has time to interact with the contaminant before the tracer slug completely passes over the contaminate region. PCUT not only identifies the presence of contamination, it also can locate the contamination along the pipeline and quantify the amount of residual. PCUT can be used in support of deactivation and decommissioning (D&D) of piping and ducts that may have been contaminated with hazardous chemicals such as chlorinated solvents, petroleum products, radioactive materials, or heavy metals, such as mercury.

  8. Simultaneous velocity and pressure quantification using pressure-sensitive flow tracers in air

    Science.gov (United States)

    Zhang, Peng; Peterson, Sean; Porfiri, Maurizio

    2017-11-01

    Particle-based measurement techniques for assessing the velocity field of a fluid have advanced rapidly over the past two decades. Full-field pressure measurement techniques have remained elusive, however. In this work, we aim to demonstrate the possibility of direct simultaneous planar velocity and pressure measurement of a high speed aerodynamic flow by employing novel pressure-sensitive tracer particles for particle image velocimetry (PIV). Specifically, the velocity and pressure variations of an airflow through a converging-diverging channel are studied. Polystyrene microparticles embedded with a pressure-sensitive phosphorescent dye-platinum octaethylporphyrin (PtOEP)-are used as seeding particles. Due to the oxygen quenching effect, the emission lifetime of PtOEP is highly sensitive to the oxygen concentration, that is, the partial pressure of oxygen, in the air. Since the partial pressure of oxygen is linearly proportional to the air pressure, we can determine the air pressure through the phosphorescence emission lifetime of the dye. The velocity field is instead obtained using traditional PIV methods. The particles have a pressure resolution on the order of 1 kPa, which may be improved by optimizing the particle size and dye concentration to suit specific flow scenarios. This work was supported by the National Science Foundation under Grant Number CBET-1332204.

  9. Prediction of postpercutaneous coronary intervention myocardial infarction: insights from intravascular imaging, coronary flow, and biomarker evaluation.

    Science.gov (United States)

    Hoole, Stephen P; Hernández-Sánchez, Jules; Brown, Adam J; Giblett, Joel P; Bennett, Martin R; West, Nick E J

    2018-05-01

    Percutaneous coronary intervention-induced myocardial infarction (PMI) has prognostic significance. Identifying patients at high risk for PMI is desirable as it may alter strategy and facilitate early preventative therapy. We therefore sought to establish whether preprocedural demographic, interventional (plaque characteristics and coronary microcirculatory function), and inflammatory, endothelial damage, and platelet-derived biomarker data could predict the risk of PMI. We performed target vessel pressure wire to assess fractional flow reserve, index of microcirculatory resistance (IMR) and coronary flow reserve, plaque characterization by virtual histology intravascular ultrasound, and assayed peripheral biomarkers before uncomplicated PCI in 88 patients. We then analyzed post-PCI cardiac troponin level to adjudicate PMI based on the third universal definition of myocardial infarction. Overall incidence of PMI was 27%. Women [10/15 (66%) vs. 14/73 (19%), PPMI. Preprocedural coronary flow reserve was lower in individuals with a subsequent PMI (1.8±1.2 vs. 2.1±1.3. P=0.03), and patients with higher pre-PCI IMR were more likely to sustain PMI [IMR>22: 10/23 (44%) vs. ≤22: 14/65 (22%), P=0.04], although neither was predictive after multivariate analysis. Plaque characterization by virtual histology intravascular ultrasound did not discriminate those at risk of PMI. However, peripheral venous interleukin (IL)-18 and IL-8 levels were independently negatively and positively associated with PMI, respectively. Women and those with low BMI, particularly when associated with high IL-8 and low IL-18 levels, appear to be at increased risk of PMI.

  10. Calculation of left ventricular volume and ejection fraction from ECG-gated myocardial SPECT. Automatic detection of endocardial borders by threshold method

    International Nuclear Information System (INIS)

    Fukushi, Shoji; Teraoka, Satomi.

    1997-01-01

    A new method which calculate end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) of the left ventricle from myocardial short axis images of ECG-gated SPECT using 99m Tc myocardial perfusion tracer has been designed. Eight frames per cardiac cycle ECG-gated 180 degrees SPECT was performed. Threshold method was used to detect myocardial borders automatically. The optimal threshold was 45% by myocardial SPECT phantom. To determine if EDV, ESV and LVEF can also be calculated by this method, 12 patients were correlated ventriculography (LVG) for 10 days each. The correlation coefficient with LVG was 0.918 (EDV), 0.935 (ESV) and 0.900 (LVEF). This method is excellent at objectivity and reproductivity because of the automatic detection of myocardial borders. It also provides useful information on heart function in addition to myocardial perfusion. (author)

  11. Myocardial multilayer strain does not provide additional value for detection of myocardial viability assessed by SPECT imaging over and beyond standard strain.

    Science.gov (United States)

    Orloff, Elisabeth; Fournier, Pauline; Bouisset, Frédéric; Moine, Thomas; Cournot, Maxime; Elbaz, Meyer; Carrié, Didier; Galinier, Michel; Lairez, Olivier; Cognet, Thomas

    2018-05-14

    The aim of this study was to evaluate the value of multilayer strain analysis to the assessment of myocardial viability (MV) through the comparison of both speckle tracking echocardiography and single-photon emission computed tomography (SPECT) imaging. We also intended to determine which segmental longitudinal strain (LS) cutoff value would be optimal to discriminate viable myocardium. We included 47 patients (average age: 61 ± 11 years) referred to our cardiac imaging center for MV evaluation. All patients underwent transthoracic echocardiography with measures of LS, SPECT, and coronary angiography. In all, 799 segments were analyzed. We correlated myocardial tracer uptake by SPECT with sub-endocardial, sub-epicardial, and mid-segmental LS values with r = .514 P Multilayer strain analysis does not evaluate MV with more accuracy than standard segmental LS analysis. © 2018 Wiley Periodicals, Inc.

  12. Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

    2015-07-15

    To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

  13. Geostatistical and Stochastic Study of Flow and Tracer Transport in the Unsaturated Zone at Yucca Mountain

    International Nuclear Information System (INIS)

    Ye, Ming; Pan, Feng; Hu, Xiaolong; Zhu, Jianting

    2007-01-01

    Yucca Mountain has been proposed by the U.S. Department of Energy as the nation's long-term, permanent geologic repository for spent nuclear fuel or high-level radioactive waste. The potential repository would be located in Yucca Mountain's unsaturated zone (UZ), which acts as a critical natural barrier delaying arrival of radionuclides to the water table. Since radionuclide transport in groundwater can pose serious threats to human health and the environment, it is important to understand how much and how fast water and radionuclides travel through the UZ to groundwater. The UZ system consists of multiple hydrogeologic units whose hydraulic and geochemical properties exhibit systematic and random spatial variation, or heterogeneity, at multiple scales. Predictions of radionuclide transport under such complicated conditions are uncertain, and the uncertainty complicates decision making and risk analysis. This project aims at using geostatistical and stochastic methods to assess uncertainty of unsaturated flow and radionuclide transport in the UZ at Yucca Mountain. Focus of this study is parameter uncertainty of hydraulic and transport properties of the UZ. The parametric uncertainty arises since limited parameter measurements are unable to deterministically describe spatial variability of the parameters. In this project, matrix porosity, permeability and sorption coefficient of the reactive tracer (neptunium) of the UZ are treated as random variables. Corresponding propagation of parametric uncertainty is quantitatively measured using mean, variance, 5th and 95th percentiles of simulated state variables (e.g., saturation, capillary pressure, percolation flux, and travel time). These statistics are evaluated using a Monte Carlo method, in which a three-dimensional flow and transport model implemented using the TOUGH2 code is executed with multiple parameter realizations of the random model parameters. The project specifically studies uncertainty of unsaturated flow

  14. Methods of measurement of myocardial blood flow in patients: a critical review

    International Nuclear Information System (INIS)

    Marcus, M.L.; Wilson, R.F.; White, C.W.

    1987-01-01

    During the past decade, major progress has been made in the evolution of technology directed toward the accurate measurement of regional myocardial perfusion in patients. The deficiencies of some of the older methods (thermodilution and gas clearance) are better appreciated and improved approaches (Doppler catheters, positron-emission tomography, and digital subtraction angiography) have been developed. The new approaches should play a major role in research and for most applications the older methods will gradually be replaced. Efforts to bring these new methods to community hospitals and practicing cardiologists should be stimulated. Doppler catheters, positron-emission tomography, and digital-subtraction angiography are commercially available and Doppler catheters and digital-subtraction angiography could be easily incorporated into routine cardiac catheterization procedures. The Doppler catheter is the most inexpensive and probably the simplest to apply. In our opinion, routine measurements of coronary flow reserve will significantly improve the care of patients with coronary obstructive disease and other diseases that impair myocardial perfusion. If coronary reserve measurements are used frequently, patient selection for coronary angioplasty and bypass surgery will no longer depend entirely on visual assessment of percent diameter stenosis, a very poor criterion in many situations. Also, patients with chest pain syndromes, normal coronary vessels, and impaired coronary reserve will be identified and perhaps some effective treatment for this condition will be devised. 77 references

  15. Optimally Repeatable Kinetic Model Variant for Myocardial Blood Flow Measurements with 82Rb PET

    Directory of Open Access Journals (Sweden)

    Adrian F. Ocneanu

    2017-01-01

    Full Text Available Purpose. Myocardial blood flow (MBF quantification with Rb82 positron emission tomography (PET is gaining clinical adoption, but improvements in precision are desired. This study aims to identify analysis variants producing the most repeatable MBF measures. Methods. 12 volunteers underwent same-day test-retest rest and dipyridamole stress imaging with dynamic Rb82 PET, from which MBF was quantified using 1-tissue-compartment kinetic model variants: (1 blood-pool versus uptake region sampled input function (Blood/Uptake-ROI, (2 dual spillover correction (SOC-On/Off, (3 right blood correction (RBC-On/Off, (4 arterial blood transit delay (Delay-On/Off, and (5 distribution volume (DV constraint (Global/Regional-DV. Repeatability of MBF, stress/rest myocardial flow reserve (MFR, and stress/rest MBF difference (ΔMBF was assessed using nonparametric reproducibility coefficients (RPCnp = 1.45 × interquartile range. Results. MBF using SOC-On, RVBC-Off, Blood-ROI, Global-DV, and Delay-Off was most repeatable for combined rest and stress: RPCnp = 0.21 mL/min/g (15.8%. Corresponding MFR and ΔMBF RPCnp were 0.42 (20.2% and 0.24 mL/min/g (23.5%. MBF repeatability improved with SOC-On at stress (p<0.001 and tended to improve with RBC-Off at both rest and stress (p<0.08. DV and ROI did not significantly influence repeatability. The Delay-On model was overdetermined and did not reliably converge. Conclusion. MBF and MFR test-retest repeatability were the best with dual spillover correction, left atrium blood input function, and global DV.

  16. Regional myocardial perfusion assessed by N-13 labeled ammonia and positron emission computerized axial tomography

    International Nuclear Information System (INIS)

    Schelbert, H.R.; Phelps, M.E.; Hoffman, E.J.; Huang, S.C.; Selin, C.E.; Kuhl, D.E.

    1978-01-01

    The usefulness of 13 NH 3 as an indicator of regional myocardial perfusion suitable for positron emission computerized axial tomography (PCT) has been suggested. However, the relationship between myocardial blood flow and uptake of 13 NH 3 has not been examined quantitatively. It was therefore the purpose of the current investigation to quantitate the relationship of myocardial 13 NH 3 tissue concentration to myocardial blood flow and to examine its suitability for PCT imaging. Twelve open chest dogs were studied. In 8 of the dogs 25 imaging procedures with 13 NH 3 and PCT were performed. In the remaining four dogs the relationship between flow and myocardial 13 NH 3 tissue concentration was assessed by in vitro techniques. The PCT technique provided high quality cross-sectional images of the distribution of 13 NH 3 in left ventricular myocardium. No significant redistribution of 13 NH 3 in myocardium occurred with time. Alterations in regional myocardial blood flow resulted in changes of the regional distribution of 13 NH 3 that were readily appreciated on the PCT images

  17. The use of C-14 as tracer in the carbon flow assimilated by the plants (maize, sugar cane, bean)

    International Nuclear Information System (INIS)

    Paula Eduardo, B. de; Cerri, C.C.

    1988-01-01

    The flow of carbon in three different crops (maize, beans and sugar cane) was studied by use of C-14. The plants were exposed to an atmosphere with a constant concentration of the tracer for 12 hours in a biosynthesis chamber. The detection of the isotope permitted the distribution and concentration of the photosynthetates in the various organs of the plants to be followed. (M.A.C.) [pt

  18. Functional significance of coronary collateral circulation during dynamic exercise evaluated by thallium-201 myocardial scintigraphy

    International Nuclear Information System (INIS)

    Wainwright, R.J.; Maisey, M.N.; Edwards, A.C.; Sowton, E.

    1980-01-01

    Sixty-five patients with angiographically documented coronary artery disease were investigated by thallium-201 ( 201 Tl) scintigraphy to determine the role of the collateral circulation during dynamic exercise. Fifty-three patients had complete proximal occlusion of at least one major coronary artery. One patient had total occlusion of all three major coronary arteries. Sixty-four collateral channels were identified, graded, and compared with corresponding regions of the myocardial scintigram. Tracer uptake was also graded and classified as various degrees of protection from ischaemia. A significant correlation between good collaterals with complete protection and poor or absent collaterals with no protection was noted. Seventeen patients (20 occluded vessels) had total coronary occlusion without myocardial infarction. Collaterals conferred protection in 9/15 occlusions whereas no protection was seen in five occlusions without collaterals. There was no difference in the protective role of homocoronary and heterocoronary collateral vessels. Hypertrophy of the first septal left anterior descending perforator conferred significant protection from ischaemia in contrast to bridging collaterals and ghosting. During exercise the right coronary bed is preferentially protected from ischaemia, in contrast to the left anterior descending territory. This probably reflects the direction of a transmural flow gradient between left and right ventricles during exercise. (author)

  19. Heat tracer test in an alluvial aquifer: Field experiment and inverse modelling

    Science.gov (United States)

    Klepikova, Maria; Wildemeersch, Samuel; Hermans, Thomas; Jamin, Pierre; Orban, Philippe; Nguyen, Frédéric; Brouyère, Serge; Dassargues, Alain

    2016-09-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in an injection well and monitoring the evolution of groundwater temperature and tracer concentration in the pumping well and in measurement intervals. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells closely spaced along three transects were used. Temperature breakthrough curves in observation wells are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. The observed complex behavior of the heat plume is explained by the groundwater flow gradient on the site and heterogeneities in the hydraulic conductivity field. Moreover, due to high injection temperatures during the field experiment a temperature-induced fluid density effect on heat transport occurred. By using a flow and heat transport numerical model with variable density coupled with a pilot point approach for inversion of the hydraulic conductivity field, the main preferential flow paths were delineated. The successful application of a field heat tracer test at this site suggests that heat tracer tests is a promising approach to image hydraulic conductivity field. This methodology could be applied in aquifer thermal energy storage (ATES) projects for assessing future efficiency that is strongly linked to the hydraulic conductivity variability in the considered aquifer.

  20. The Influence of findings of coronary artery on myocardial salvage in acute myocardial infarction

    International Nuclear Information System (INIS)

    Itano, Midoriko; Naruse, Hitoshi; Morita, Masato; Kawamoto, Hideo; Yamamoto, Juro; Fukutake, Naoshige; Ohyanagi, Mitsumasa; Iwasaki, Tadaaki; Fukuchi, Minoru

    1992-01-01

    201 Tl stress myocardial scintigraphy was performed in convalescent patients with acute myocardial infarction, to evaluate the influence of stenosis and collateral circulation of coronary artery in acute phase, on myocardial salvage in chronic phase. In 14 cases of unsuccessful coronary revascularization (complete occlusion), a complete defect of thallium imaging in chronic phase was seen in only one case of four cases with good collateral circulation, while eight of 10 cases with poor collateral circulation. In 16 cases with collateral circulation, six cases showed a complete defect, although the target vessel had improved to less than 75% of stenosis. However, in cases of good collateral circulation, no case showed a complete defect when the target vessel had improved to less than 75% of stenosis. The myocardial salvage is quite possible (p<0.05), when the coronary angiography in acute phase showed the forward flow (99% or 90% of stenosis) before coronary revascularization and/or good collateral circulation (Rentrop 2deg or 3deg). (author)

  1. SURGERY OF SYMPTOMATIC MYOCARDIAL BRIDGING

    Directory of Open Access Journals (Sweden)

    N. Maghamipour N. Safaei

    2007-06-01

    Full Text Available Myocardial bridging with systolic compression of the left anterior descending coronary artery (LAD may be associated with myocardial ischemia. In symptomatic myocardial bridging unresponsive to medical treatment, surgical unroofing of the left LAD can be performed. Little information is available about the long-term prognosis of patients with this coronary anomaly after the surgical unroofing, so we decided to evaluate the result of this operation. A total of 26 patients underwent surgical unroofing of myocardial bridging. Patients had a myocardial bridge of at least 3 cm in length in the middle of LAD and with more than 70% compression during systole. Unroofing was performed with cardiopulmonary bypass in 16 and with off pump technique in 10 patients. In 6 patients repeat angiographies for control of myotomy were done. In one of them a nonsignificant 20% narrowing was seen. Postoperative scintigraphic and angiographic studies demonstrated restoration of coronary flow and myocardial perfusion without residual myocardial bridges under beta-stimulation in 24 patients. Two patients had residual narrowing. With off pump technique, 1 patient had perforation of the right ventricle and 1 patient underwent reoperation because of incomplete unroofing during the first operation. None of the patients with cardiopulmonary bypass technique had residual chest pain or other complications. Surgical unroofing of myocardial bridging with the aid of cardiopulmonary bypass is a safe and easy procedure with low operative risk and with excellent functional results.

  2. Thallium-201 myocardial imaging in the detection of coronary artery disease

    International Nuclear Information System (INIS)

    McKillop, J.H.; Murray, R.G.; Turner, J.G.; Gray, H.W.; Bessent, R.G.; Lorimer, A.R.; Greig, W.R.

    1978-01-01

    Thallium-201 myocardial imaging can detect abnormalities of myocardial perfusion. Visual interpretation of the images is complicated by some inhomogeneity of tracer uptake normally present. Using a quantitative approach we have established the regional variation of Thallium-201 uptake present in 23 normal controls and applied the same technique to 49 patients who had undergone selective coronary arteriography with left ventriculography because of chest pain. Half of the patients with significant coronary artery disease had abnormal rest Thallium-201 images, usually corresponding to areas of abnormal wall motion at ventriculography. Stress Thallium-201 images were abnormal in over 90% of patients with coronary artery disease. The stress image abnormalities and the arteriographic lesions correlated well in most patients with single and double vessel disease but in triple vessel disease the correspondence between the two studies was poor. Two of a group of patients with normal coronary arteriograms had abnormal Thallium-201 images due to other myocardial pathology. Our technique was highly sensitive in the non-invasive detection of significant coronary artery disease in a group of patients with chest pain. A small number of positive studies were also encountered due to other myocardial disorders. (author)

  3. Statistically Based Morphodynamic Modeling of Tracer Slowdown

    Science.gov (United States)

    Borhani, S.; Ghasemi, A.; Hill, K. M.; Viparelli, E.

    2017-12-01

    Tracer particles are used to study bedload transport in gravel-bed rivers. One of the advantages associated with using of tracer particles is that they allow for direct measures of the entrainment rates and their size distributions. The main issue in large scale studies with tracer particles is the difference between tracer stone short term and long term behavior. This difference is due to the fact that particles undergo vertical mixing or move to less active locations such as bars or even floodplains. For these reasons the average virtual velocity of tracer particle decreases in time, i.e. the tracer slowdown. In summary, tracer slowdown can have a significant impact on the estimation of bedload transport rate or long term dispersal of contaminated sediment. The vast majority of the morphodynamic models that account for the non-uniformity of the bed material (tracer and not tracer, in this case) are based on a discrete description of the alluvial deposit. The deposit is divided in two different regions; the active layer and the substrate. The active layer is a thin layer in the topmost part of the deposit whose particles can interact with the bed material transport. The substrate is the part of the deposit below the active layer. Due to the discrete representation of the alluvial deposit, active layer models are not able to reproduce tracer slowdown. In this study we try to model the slowdown of tracer particles with the continuous Parker-Paola-Leclair morphodynamic framework. This continuous, i.e. not layer-based, framework is based on a stochastic description of the temporal variation of bed surface elevation, and of the elevation specific particle entrainment and deposition. Particle entrainment rates are computed as a function of the flow and sediment characteristics, while particle deposition is estimated with a step length formulation. Here we present one of the first implementation of the continuum framework at laboratory scale, its validation against

  4. Myocardial imaging in acute myocardial infarction using. beta. -methyl-p-( sup 123 I)-iodophenylpentadecanoic acid; Comparison with sup 201 Tl imaging and wall motion

    Energy Technology Data Exchange (ETDEWEB)

    Naruse, Hitoshi; Itano, Midoriko; Kondo, Tomohiro (Hyogo College of Medicine, Nishinomiya (Japan)) (and others)

    1992-01-01

    Myocardial imaging using {beta}-methyl-p-({sup 123}I)-iodophenylpentadecanoic acid (BMIPP) was performed in 11 patients with acute myocardial infarction. The left ventricular images were divided into 12 segments, and myocardial images with BMIPP were compared with coronary angiography (CAG), thallium-201 myocardial scintigraphy (Tl) and wall motion obtained by two-dimensional echocardiography (WM). When the culprit lesion was at the proximal point of the left anterior descending artery (LAD), all segments showed depressed uptake. In 3 cases with single vessel disease of the LAD, inferior wall of the basis showed reduced uptake of BMIPP despite the location of the culprit lesion. In cases with discordant uptake between the two tracers, BMIPP frequently showed more severely depressed uptake than Tl in the subacute phase, although the uptake of BMIPP correlated with that of Tl ({tau}=0.82, p<0.001). In such cases, the discordance was related to the improvement in WM from the acute phase to the convalescent phase. BMIPP uptake correlated with WM in the subacute phase ({tau}=0.50, p<0.001). BMIPP showed more severely depressed uptake while WM showed mild asynergy in most cases in which discordance was found between the BMIPP and WM findings. However, there was no correlation between the change in WM from the acute to subacute phases, or the uptakes of BMIPP and Tl alone. We concluded that the myocardial condition can be evaluated in detail in acute myocardial infarction by comparing the findings of BMIPP with those of Tl and WM. (author).

  5. First technical report about tracer applications to processes assessment in a portable water potabilizing plant

    International Nuclear Information System (INIS)

    Suarez Antola, R.; Giosa Porley, P.

    1996-03-01

    Radioactive and fluorescent tracers were applied to measure the distribution of residence times in each of the four subsystems of a portable water purifying plant: the mechanical flocculation unit, the hydraulic flocculation unit, the sedimentation unit, and the sand filter. This report begins by a revision of the physicochemical processes produced in each of the above mentioned subsystems, connected in series. Then a mathematical model of residence time distribution for each unit is constructed, with free parameters that can be estimated from the experimental results obtained with tracers. Tracer methodology for this kind of field experiment is reviewed. Their possible short comes are briefly discussed for each of the intended tracers. The tracer experiments done with rhodamine and uranine are described. The experimental results are reported and the residence time distributions obtained with different tracers were carefully compared. In order to make the field experiments, five different values of global water flow were sustained, pumping in steady state: two under the nominal (design) value, two above the design flow and one equal to the nominal water flow. The model parameters were determined using a software package, D TR , made in France and supplied by the IAEA in the framework of the project. It was discovered that the diffuser in the sedimentation unit was not working as intended, and some guidelines for its re-design could be given to the process engineers. Also, process engineers received information about some amount of by-pass flow and death zones, as well as their variations with plant's global water flow

  6. Determining Near-Bottom Fluxes of Passive Tracers in Aquatic Environments

    Science.gov (United States)

    Bluteau, Cynthia E.; Ivey, Gregory N.; Donis, Daphne; McGinnis, Daniel F.

    2018-03-01

    In aquatic systems, the eddy correlation method (ECM) provides vertical flux measurements near the sediment-water interface. The ECM independently measures the turbulent vertical velocities w' and the turbulent tracer concentration c' at a high sampling rate (> 1 Hz) to obtain the vertical flux w'c'¯ from their time-averaged covariance. This method requires identifying and resolving all the flow-dependent time (and length) scales contributing to w'c'¯. With increasingly energetic flows, we demonstrate that the ECM's current technology precludes resolving the smallest flux-contributing scales. To avoid these difficulties, we show that for passive tracers such as dissolved oxygen, w'c'¯ can be measured from estimates of two scalar quantities: the rate of turbulent kinetic energy dissipation ɛ and the rate of tracer variance dissipation χc. Applying this approach to both laboratory and field observations demonstrates that w'c'¯ is well resolved by the new method and can provide flux estimates in more energetic flows where the ECM cannot be used.

  7. Tracer studies of flotation in laboratory and plant

    International Nuclear Information System (INIS)

    Niemi, A.J.; Thereska, J.; Plasari, E.; Kacaj, M.

    1992-01-01

    Froth flotation is used for the industrial extraction of valuable minerals from ores. Its progress depends on the properties of minerals being processed and on flotation practices. While flotation is basically a kinetic process, it functions industrially in continuous flow vessels whose flow patterns influence the separation effected. Radioisotope tracers have proven to be a necessary tool in the acquisition of both kinetic and flow pattern data

  8. Decreased myocardial 123I-MIBF uptake in Parkinson's disease

    International Nuclear Information System (INIS)

    Iwasa, K.; Takamori, M.; Nakajima, K.; Taki, J.; Yoshikawa, H.; Tada, A.

    1998-01-01

    We studied myocardial 123 I-metaiodobenzylguanidine (MIBG) accumulation in 12 patients with Parkinson's disease (PD). MIBG is an analog of norepinephrine (NE) and a tracer for sympathetic neuron integrity and function. MIBG uptake of the myocardium was significantly lower in PD than in controls. The heart to mediastinum ratio (H/M) was calculated by using the average count per pixel for the heart and mediastinum. In PD, H/M was lower than in controls (P<0.0001), while the washout ratio of the heart was higher (P<0.001). A decrease in myocardial accumulation of MIBG was observed in the early stage of PD. This suggests that the measurement of MIBF may help the diagnosis of early PD, and the causative factor underlying in PD may be operating the NE neuron as well as dopamine neuron. (au)

  9. Final report of the TRUE Block Scale project. 2. Tracer tests in the block scale

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Peter; Byegaard, Johan [Geosigma AB, Uppsala (Sweden); Winberg, Anders [Conterra AB, Partille (Sweden)

    2002-05-01

    The tracer test programme of the TRUE Block Scale Project involved 14 tracer tests campaigns, including performance of 32 tracer injections in 16 different combinations of source and sink sections (flow paths) varying in length between 10 to 130 metres, and involving one or more structures. Average, travel times varied between 1.5 and >2000 hours. Tracer dilution tests performed in conjunction with cross-hole hydraulic pumping tests were found to be a very important part of the pre-tests, where the results were used to identify and screen among possible injection points, and to verify the hydrostructural model valid at a given time. The main problem faced in the block scale tests was to select a test geometry, which gave a sufficiently high mass recovery, and at the same time enabled performance of cross-hole sorbing tracer tests within reasonable time frames. Three different injection methods were applied during the test programme; decaying pulse, finite pulse and forced pulse (unequal dipole). During the later phases of the tracer test programme it was identified that forced injection had to be employed in order to enable detection of tracer at the sink due to strong dilution, and also to avoid problems with artificially induced tailing in the injection signal. Sorbing (reactive) tracers were selected among the radioactive isotopes of the alkali and alkaline earth metals previously used in the TRUE- 1 experiments. It was decided that at least one slightly sorbing tracer and one strongly sorbing tracer should be used in each injection. Non-sorbing tracers were used for conservative reference, e.g., {sup 82}Br{sup -}, {sup 186}ReO{sub 4}, HTO (tritiated water) and {sup 131}I{sup -}. In two of the injections the radioactive non-sorbing tracers were rather short-lived and Uranine and Naphthionate were used as complementary conservative tracers. Surface distribution coefficients, K{sub a}, were evaluated from TRUE-1 and TRUE Block Scale data, making use of the

  10. Final report of the TRUE Block Scale project. 2. Tracer tests in the block scale

    International Nuclear Information System (INIS)

    Andersson, Peter; Byegaard, Johan; Winberg, Anders

    2002-05-01

    The tracer test programme of the TRUE Block Scale Project involved 14 tracer tests campaigns, including performance of 32 tracer injections in 16 different combinations of source and sink sections (flow paths) varying in length between 10 to 130 metres, and involving one or more structures. Average, travel times varied between 1.5 and >2000 hours. Tracer dilution tests performed in conjunction with cross-hole hydraulic pumping tests were found to be a very important part of the pre-tests, where the results were used to identify and screen among possible injection points, and to verify the hydrostructural model valid at a given time. The main problem faced in the block scale tests was to select a test geometry, which gave a sufficiently high mass recovery, and at the same time enabled performance of cross-hole sorbing tracer tests within reasonable time frames. Three different injection methods were applied during the test programme; decaying pulse, finite pulse and forced pulse (unequal dipole). During the later phases of the tracer test programme it was identified that forced injection had to be employed in order to enable detection of tracer at the sink due to strong dilution, and also to avoid problems with artificially induced tailing in the injection signal. Sorbing (reactive) tracers were selected among the radioactive isotopes of the alkali and alkaline earth metals previously used in the TRUE- 1 experiments. It was decided that at least one slightly sorbing tracer and one strongly sorbing tracer should be used in each injection. Non-sorbing tracers were used for conservative reference, e.g., 82 Br - , 186 ReO 4 , HTO (tritiated water) and 131 I - . In two of the injections the radioactive non-sorbing tracers were rather short-lived and Uranine and Naphthionate were used as complementary conservative tracers. Surface distribution coefficients, K a , were evaluated from TRUE-1 and TRUE Block Scale data, making use of the retardation noted in the injection

  11. Nitrate movement and removal along a shallow groundwater flow path in a riparian wetland within a sheep-grazed pastoral catchment : result of a tracer study

    International Nuclear Information System (INIS)

    Burns, D.A.; Nguyen, L.

    2002-01-01

    The movement and removal of nitrate (NO 3 ) along a groundwater flow path within a riparian wetland was investigated during a 24-day period in late autumn-early winter, using a lithium bromide (LiBr)-potassium nitrate (KNO 3 ) tracer solution containing 19 200 mg/litre as Br - and 193.8 mg/litre as NO 3 -N. The tracer solution was added as an instantaneous dose of tracer solution at a depth of 10-20 cm to four injection wells in two 1 m 2 plots within a sheep-grazed pastoral catchment at the Whatawhata Agricultural Research Centre near Hamilton, New Zealand. Bromide and NO 3- N concentrations were measured periodically in: (1) wetland groundwater samples from piezometers installed at 15 and 30 cm depths and located at 30, 60, and 100 cm down gradient from the injection wells; and (2) surface flow samples. Peak concentrations of 50-250 mg/litre of Br - and 0.2-1.1 mg/litre of NO 3 -N were reached within 1-2 days after application at most piezometers. Nitrate concentrations decreased thereafter more sharply than did those of Br - , resulting in decreased NO 3 -N/Br - ratios from Days 2 through 7. More than 99% of groundwater samples collected after the tracer application had NO 3 -N/Br - less than the value in the tracer solution indicating removal of NO 3 -N during transport. Mass flux estimates indicated removal of >90% of added NO 3 -N along the 100 cm flow path from the injection, with essentially all of the NO 3 - removed within the first 30 cm of transport. On Days 10 and 24, just after rain events, surface flow from the experimental plots had greatly elevated NO 3 -N concentrations that were not accompanied by correspondingly elevated Br - concentrations, indicating that NO 3 -N originating from the surrounding catchment was transported over the wetland surface with little penetration or mixing with wetland groundwater. Despite a significant capacity for NO 3 -N removal from shallow groundwater equivalent to an annualised value of 50 kg/ha in these wetland

  12. Fractional Flow Reserve-Guided Complete Revascularization Improves the Prognosis in Patients With ST-Segment-Elevation Myocardial Infarction and Severe Nonculprit Disease

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Engstrøm, Thomas; Kelbæk, Henning

    2017-01-01

    , and severity of the noninfarct-related stenosis on the effect of fractional flow reserve-guided complete revascularization. METHODS AND RESULTS: In the DANAMI-3-PRIMULTI study (Primary PCI in Patients With ST-Elevation Myocardial Infarction and Multivessel Disease: Treatment of Culprit Lesion Only or Complete...

  13. Performance Testing of Tracer Gas and Tracer Aerosol Detectors for use in Radionuclide NESHAP Compliance Testing

    Energy Technology Data Exchange (ETDEWEB)

    Fuehne, David Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lattin, Rebecca Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-28

    The Rad-NESHAP program, part of the Air Quality Compliance team of LANL’s Compliance Programs group (EPC-CP), and the Radiation Instrumentation & Calibration team, part of the Radiation Protection Services group (RP-SVS), frequently partner on issues relating to characterizing air flow streams. This memo documents the most recent example of this partnership, involving performance testing of sulfur hexafluoride detectors for use in stack gas mixing tests. Additionally, members of the Rad-NESHAP program performed a functional trending test on a pair of optical particle counters, comparing results from a non-calibrated instrument to a calibrated instrument. Prior to commissioning a new stack sampling system, the ANSI Standard for stack sampling requires that the stack sample location must meet several criteria, including uniformity of tracer gas and aerosol mixing in the air stream. For these mix tests, tracer media (sulfur hexafluoride gas or liquid oil aerosol particles) are injected into the stack air stream and the resulting air concentrations are measured across the plane of the stack at the proposed sampling location. The coefficient of variation of these media concentrations must be under 20% when evaluated over the central 2/3 area of the stack or duct. The instruments which measure these air concentrations must be tested prior to the stack tests in order to ensure their linear response to varying air concentrations of either tracer gas or tracer aerosol. The instruments used in tracer gas and aerosol mix testing cannot be calibrated by the LANL Standards and Calibration Laboratory, so they would normally be sent off-site for factory calibration by the vendor. Operational requirements can prevent formal factory calibration of some instruments after they have been used in hazardous settings, e.g., within a radiological facility with potential airborne contamination. The performance tests described in this document are intended to demonstrate the reliable

  14. Regional myocardial oxygen consumption determined noninvasively in humans with [1-11C]acetate and dynamic positron tomography

    International Nuclear Information System (INIS)

    Armbrecht, J.J.; Buxton, D.B.; Brunken, R.C.; Phelps, M.E.; Schelbert, H.R.

    1989-01-01

    Experimental studies of animals have previously demonstrated the validity of [1-11C]acetate as a tracer of oxidative metabolism for use with positron emission tomography. The present study was undertaken to define in normal human volunteers the relation between myocardial clearance kinetics of [1-11C]acetate, and the rate-pressure product as an index of myocardial oxygen consumption. Twenty-two studies were performed of 12 volunteers. The rate-pressure product was increased with continuous supine bicycle exercise in six studies. Of the 16 resting studies, seven were performed in the fasted state and nine following an oral glucose load, to define possible effects of substrate availability on the tracer-tissue kinetics. Myocardial tissue time-activity curves were biexponential. Clearance of activity was homogeneous throughout the myocardium. The rate constants k1, obtained from biexponential fitting, and kmono, obtained by monoexponential fitting of the initial linear portion of the time-activity curves, correlated well with the rate-pressure product. Although the correlation coefficient was higher for k1 than for kmono (0.95 vs. 0.91), analysis on a sectorial basis showed less regional variability in kmono. This suggests that kmono, which is more practical than k1 because it requires shorter acquisition times, may be more clinically and experimentally useful for detection of myocardial segments with abnormal oxygen consumption. Overall, changes in myocardial substrate supply were without significant effect on the relation between the rate constants (k1 and kmono) and the rate-pressure product, although a small decrease in kmono/rate-pressure product was observed following oral glucose by paired analysis in four subjects

  15. Myocardial Damage in Patients With Deferred Stenting After STEMI

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Engstrøm, Thomas; Ahtarovski, Kiril Aleksov

    2017-01-01

    BACKGROUND: Although some studies found improved coronary flow and myocardial salvage when stent implantation was deferred, the DANAMI-3-DEFER (Third DANish Study of Optimal Acute Treatment of Patients With ST-elevation Myocardial Infarction) did not show any improvement in clinical outcome in pa...

  16. Tracer techniques in karst hydrogeology. Application to the location of karst aquifers

    International Nuclear Information System (INIS)

    Mangin, A.; Molinari, J.

    1976-01-01

    From the recent progress in karst aquifer simulation techniques and the improved knowledge of tracers, the old-established tracer technique has become an invaluable instrument for hydrogeological survey work. Typical information obtainable includes karst system boundaries features and location of hydrodynamic discontinuities, flow variation in both space and time. Tracer methods are a basic requirement for investigation of karst groundwater supplies and determining protection zones for water supply points [fr

  17. Dual myocardial single photon emission computed tomography (SPECT) using thallium-201 and I-123-β-methyl-i-pentadecanoic acid in patients with Duchenne's progressive muscular dystrophy

    International Nuclear Information System (INIS)

    Shimoyama, Katsuya

    1999-01-01

    Dual single photon emission computed tomography (SPECT) was performed in 31 patients with Duchenne's progressive muscular dystrophy (DMD) using 123 I-β-methyl pentadecanoic acid (BMIPP) for myocardial fatty acid metabolism and 201 thallium (Tl)-chloride for myocardial perfusion. The left ventricle was divided into 9 segments, and accumulation of the radiotracers was assessed visually for each segment to calculate defect score for each tracer. There was some degree of decrease in myocardial accumulation of both tracers in all DMD patients. Reduced accumulation was most common at the apex (BMIPP: 67%, Tl: 63%), followed by the posterior wall, lateral wall, and anterior wall. On the other hand, reduced accumulation was less common at the septum. BMIPP showed a higher accumulation than Tl in all segments but the septum. When BMIPP defect score was larger than Tl defect score, BMIPP defect score tended to increase during 4 years follow-up (p Tl defect score revealed a slight fibrosis or normal myocardium. It can be concluded that the dual SPECT myocardial scintigraphy using BMIPP and Tl provides accurate information about disease progression of the heart in patients with DMD by detecting abnormalities of the myocardial metabolism of each substance, thereby enabling the assessment of left ventricular function. (author)

  18. Biodistribution and stability studies of [18F]Fluoroethylrhodamine B, a potential PET myocardial perfusion agent

    International Nuclear Information System (INIS)

    Gottumukkala, Vijay; Heinrich, Tobias K.; Baker, Amanda; Dunning, Patricia; Fahey, Frederic H.; Treves, S. Ted; Packard, Alan B.

    2010-01-01

    Introduction: Fluorine-18-labeled rhodamine B was developed as a potential positron emission tomography (PET) tracer for the evaluation of myocardial perfusion, but preliminary studies in mice showed no accumulation in the heart suggesting that it was rapidly hydrolyzed in vivo in mice. A study was therefore undertaken to further evaluate this hypothesis. Methods: [ 18 F]Fluoroethylrhodamine B was equilibrated for 2 h at 37 deg. C in human, rat and mouse serum and in phosphate-buffered saline. Samples were removed periodically and assayed by high-performance liquid chromatography. Based on the results of the stability study, microPET imaging and a biodistribution study were carried out in rats. Results: In vitro stability studies demonstrated that [ 18 F]fluoroethylrhodamine B much more stable in rat and human sera than in mouse serum. After 2 h, the compound was >80% intact in rat serum but 18 F-labeled rhodamines should accumulate in the heart. Conclusions: [ 18 F]Fluoroethylrhodamine B is more stable in rat and human sera than it is in mouse serum. This improved stability is demonstrated by the high uptake of the tracer in the rat heart in comparison to the absence of visible uptake in the mouse heart. These observations suggest that 18 F-labeled rhodamines are promising candidates for more extensive evaluation as PET tracers for the evaluation of myocardial perfusion.

  19. Some atmospheric tracer experiments in complex terrain at LASL: experimental design and data

    International Nuclear Information System (INIS)

    Archuleta, J.; Barr, S.; Clements, W.E.; Gedayloo, T.; Wilson, S.K.

    1978-03-01

    Two series of atmospheric tracer experiments were conducted in complex terrain situations in and around the Los Alamos Scientific Laboratory. Fluorescent particle tracers were used to investigate nighttime drainage flow in Los Alamos Canyon and daytime flow across the local canyon-mesa complex. This report describes the details of these experiments and presents a summary of the data collected. A subsequent report will discuss the analysis of these data

  20. Peak-counts blood flow model-errors and limitations

    International Nuclear Information System (INIS)

    Mullani, N.A.; Marani, S.K.; Ekas, R.D.; Gould, K.L.

    1984-01-01

    The peak-counts model has several advantages, but its use may be limited due to the condition that the venous egress may not be negligible at the time of peak-counts. Consequently, blood flow measurements by the peak-counts model will depend on the bolus size, bolus duration, and the minimum transit time of the bolus through the region of interest. The effect of bolus size on the measurement of extraction fraction and blood flow was evaluated by injecting 1 to 30ml of rubidium chloride in the femoral vein of a dog and measuring the myocardial activity with a beta probe over the heart. Regional blood flow measurements were not found to vary with bolus sizes up to 30ml. The effect of bolus duration was studied by injecting a 10cc bolus of tracer at different speeds in the femoral vein of a dog. All intravenous injections undergo a broadening of the bolus duration due to the transit time of the tracer through the lungs and the heart. This transit time was found to range from 4-6 second FWHM and dominates the duration of the bolus to the myocardium for up to 3 second injections. A computer simulation has been carried out in which the different parameters of delay time, extraction fraction, and bolus duration can be changed to assess the errors in the peak-counts model. The results of the simulations show that the error will be greatest for short transit time delays and for low extraction fractions

  1. Feasibility and diagnostic power of transthoracic coronary Doppler for coronary flow velocity reserve in patients referred for myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Nylander Eva

    2008-03-01

    Full Text Available Abstract Background Myocardial perfusion imaging (MPI, using single photon emission computed tomography (SPECT is a validated method for detecting coronary artery disease. Transthoracic Doppler echocardiography (TTDE of flow at rest and during adenosine provocation has previously been evaluated in selected patient groups. We therefore wanted to compare the diagnostic ability of TTDE in the left anterior descending coronary artery (LAD to that of MPI in an unselected population of patients with chest pain referred for MPI. Our hypothesis was that TTDE with high accuracy would identify healthy individuals and exclude them from the need for further studies, enabling invasive investigations to be reserved for patients with a high probability of disease. Methods Sixty-nine patients, 44 men and 25 women, age 61 ± 10 years (range 35–82, with a clinical suspicion of stress induced myocardial ischemia, were investigated. TTDE was performed at rest and during adenosine stress for myocardial scintigraphy. Results We found that coronary flow velocity reserve (CFVR determined from diastolic measurements separated normal from abnormal MPI findings with statistical significance. TTDE identified coronary artery disease, defined from MPI, as reversible ischemia and/or permanent defect, with a sensitivity of 60% and a specificity of 79%. The positive predictive value was 43% and the negative predictive value was 88%. There was an overlap between groups which could be due to abnormal endothelial function in patients with normal myocardial perfusion having either hypertension or diabetes. Conclusion TTDE is an attractive non-invasive method to evaluate chest pain without the use of isotopes, but the diagnostic power is strongly dependent on the population investigated. Even in our heterogeneous clinical cardiac population, we found that CFVR>2 in the LAD excluded significant coronary artery disease detected by MPI.

  2. Development and application of a modified wireless tracer for disaster prevention

    Science.gov (United States)

    Chung Yang, Han; Su, Chih Chiang

    2016-04-01

    Typhoon-induced flooding causes water overflow in a river channel, which results in general and bridge scour and soil erosion, thus leading to bridge failure, debris flow and landslide collapse. Therefore, dynamic measurement technology should be developed to assess scour in channels and landslide as a disaster-prevention measure against bridge failure and debris flow. This paper presents a wireless tracer that enables monitoring general scour in river channels and soil erosion in hillsides. The wireless tracer comprises a wireless high-power radio modem, various electronic components, and a self-designed printed circuit board that are all combined with a 9-V battery pack and an auto switch. The entire device is sealed in a jar by silicon. After it was modified, the wireless tracer underwent the following tests for practical applications: power continuation and durability, water penetration, and signal transmission during floating. A regression correlation between the wireless tracer's transmission signal and distance was also established. This device can be embedded at any location where scouring is monitored, and, in contrast to its counterparts that detect scour depth by identifying and analyzing received signals, it enables real-time observation of the scouring process. In summary, the wireless tracer developed in this study provides a dynamic technology for real-time monitoring of scouring (or erosion) and forecasting of landslide hazards. Keywords: wireless tracer; scour; real-time monitoring; landslide hazard.

  3. Comparison of myocardial blood flow induced by adenosine triphosphate and dipyridamole in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Mamede, M.; Tadamura, Eiji; Hosokawa, Ryohei

    2005-01-01

    Myocardial perfusion imaging with adenosine triphosphate (ATP) has been used increasingly to diagnose coronary artery disease (CAD) and assess risk for this disease. This study compared absolute myocardial blood flow (MBF) and myocardial flow reserve index (MFR) with ATP and dipyridamole (DIP) in patients with CAD. MBF was quantified by 15 O-H 2 O PET in 21 patients with CAD (17 male, 4 female), aged 55 to 81 years. MBF was measured at rest, during intravenous injection of ATP (0.16 mg/kg/min), and again after DIP infusion (0.56 mg/kg). Regions of interest were drawn in nonischemic and ischemic segments based on findings from thallium-201 ( 201 Tl) scintigraphy and coronary angiography (CAG). Absolute MBF values and indexes of MFR were calculated in nonischemic and ischemic segments. Intravenous injection of ATP and DIP significantly increased MBF in nonischemic (2.4±0.9 and 2.1±0.8 ml/g/min, respectively; p<0.01, for both) and in ischemic segments (1.3±0.4 and 1.5±0.4 ml/g/min, respectively; p<0.01, for both). There was a significant difference in MBF values between ATP and DIP in nonischemic segments (p<0.05), which was not observed in ischemic segments. In nonischemic segments, ATP produced higher MFR than DIP (2.1±0.8 and 1.8±0.7, respectively; p<0.05), while no significant difference was observed in ischemic segments (1.5±0.6 and 1.7±0.3, respectively). ATP produced a greater hyperemia than DIP between the ischemic and nonischemic myocardium in patients with CAD. ATP is as effective as DIP for the diagnosis of CAD. (author)

  4. Tumoral tracers

    International Nuclear Information System (INIS)

    Camargo, E.E.

    1979-01-01

    Direct tumor tracers are subdivided in the following categories:metabolite tracers, antitumoral tracers, radioactive proteins and cations. Use of 67 Ga-citrate as a clinically important tumoral tracer is emphasized and gallium-67 whole-body scintigraphy is discussed in detail. (M.A.) [pt

  5. A comparison between 99Tcm-tetrofosmin and 99Tcm-MIBI myocardial perfusion imaging in detection of silent myocardial ischemia

    International Nuclear Information System (INIS)

    Fu Wei; Tang Yi; Liu Xuemei; Fan Yan; Liu Tao

    2012-01-01

    Objective: To compare 99 Tc m -tetrofosmin (TF) and 99 Tc m -MIBI adenosine stress/resting MPI in detection of silent myocardial ischemia (SMI). Methods: According to the WHO diagnostic criteria for coronary heart disease (CHD), 306 SMI patients were classified to three groups as type Ⅰ (n=122), type Ⅱ (n=112) and type Ⅲ (n=72). The subjects of each type were randomly divided into 2 subgroups; one subgroup underwent adenosine stress/rest MPI with 99 Tc m -MIBI and another subgroup with 99 Tc m -TF. The clinical diagnosis of CHD was proven with electrocardiogram (46 cases), dynamic electrocardiogram (219 cases) or CAG (41 cases). Comparison factors between the two tracers included image quality and diagnostic efficacy. The image quality was graded into three classes:excellent, good and moderate. χ 2 test and analysis of variance were used to analyze data. Results: The sensitivities of detecting myocardial ischemia with 99 Tc m -MIBI MPI and 99 Tc m -TF MPI in group type Ⅰ were 57.38% (35/61) vs 60.66% (37/61) (χ 2 =0.136, P>0.05); in group type Ⅱ 69.64% (39/56) vs 64.29% (36/56) (χ 2 =0.363, P>0.05) and in group type Ⅲ 83.33% (30/36) vs 88.89% (32/36) (χ 2 =0.465, P>0.05), respectively. There was no significant difference between the sensitivities of the two imaging modalities in all three types of SMI patients.In image quality grading, 99 Tc m -MIBI and 99 Tc m -TF demonstrated excellent images with 41.18% (63/153) vs 48.37% (74/153) (χ 2 =1.599, P=0.206), good with 45.10% (69/153) vs 34.64% (53/153) (χ 2 =3.489, P=0.062) and moderate with 13.72% (21/153) vs 16.99%(26/153) (χ 2 =0.628, P=0.428). There was no unqualified image with either modality. 99 Tc m -TF displayed quicker radioactivity clearance in liver and lungs. Thereby there was less interference or pitfalls present in the ventricle base or interior wall that may result from higher liver radioactivity retention. The waiting time between the tracer injection and imaging was at least 1 h

  6. Using stable isotope tracers to assess hydrological flow paths, residence times and landscape influences in a nested mesoscale catchment

    Directory of Open Access Journals (Sweden)

    P. Rodgers

    2005-01-01

    Full Text Available δ18O measurements in precipitation and stream waters were used to investigate hydrological flow paths and residence times at nested spatial scales in the mesoscale (233 km2 River Feugh catchment in the northeast of Scotland over the 2001-2002 hydrological year. Precipitation δ18O exhibited strong seasonal variation, which although significantly damped within the catchment, was reflected in stream water at six sampling sites. This allowed δ18O variations to be used to infer the relative influence of soil-derived storm flows with a seasonally variable isotopic signature, and groundwater of apparently more constant isotopic composition. Periodic regression analysis was then used to examine the sub-catchment difference using an exponential flow model to provide indicative estimates of mean stream water residence times, which varied between approximately 3 and 14 months. This showed that the effects of increasing scale on estimated mean stream water residence time was minimal beyond that of the smallest (ca. 1 km2 headwater catchment scale. Instead, the interaction of catchment soil cover and topography appeared to be the dominant controlling influence. Where sub-catchments had extensive peat coverage, responsive hydrological pathways produced seasonally variable δ18O signatures in runoff with short mean residence times (ca. 3 months. In contrast, areas dominated by steeper slopes, more freely draining soils and larger groundwater storage in shallow valley-bottom aquifers, deeper flow paths allow for more effective mixing and damping of δ18O indicating longer residence times (>12 months. These insights from δ18O measurements extend the hydrological understanding of the Feugh catchment gained from previous geochemical tracer studies, and demonstrate the utility of isotope tracers in investigating the interaction of hydrological processes and catchment characteristics at larger spatial scales.

  7. Results of repeat tracer tests at Ohaaki, NZ

    International Nuclear Information System (INIS)

    McCabe, W.J.; Morris, C.

    1995-01-01

    During 20 years of tracer testing at Ohaaki a number of wells have been used more than once as tracer injection sites. In studying the various responses obtained it has been necessary to consider variations in the experimental test conditions before making comparisons which relate to field conditions. Some very significant changes have occurred in the field hydrology in recent years and water flow speeds as high as those encountered at Wairakei have been demonstrated. (author). 4 refs., 2 tabs., 10 figs

  8. Comparison of the myocardial blood flow response to regadenoson and dipyridamole: a quantitative analysis in patients referred for clinical 82Rb myocardial perfusion PET

    International Nuclear Information System (INIS)

    Goudarzi, Behnaz; Fukushima, Kenji; Bravo, Paco; Merrill, Jennifer; Bengel, Frank M.

    2011-01-01

    Regadenoson is a novel selective A 2A adenosine receptor agonist, which is administered as an intravenous bolus at a fixed dose. It is currently not clear if the absolute flow increase in response to this fixed dose is a function of distribution volume in individual patients or if it is generally comparable to the previous standard agents dipyridamole or adenosine, which are dosed based on weight. We used quantitative analysis of clinical 82 Rb PET/CT studies to obtain further insights. A total of 104 subjects with normal clinical rest/stress 82 Rb perfusion PET/CT were included in a retrospective analysis. To rule out confounding factors, none had evidence of prior cardiac disease, ischaemia or infarction, cardiomyopathy, diabetes with insulin use, calcium score >400, renal disease or other significant systemic disease. A group of 52 patients stressed with regadenoson were compared with a group of 52 patients stressed with dipyridamole before regadenoson became available. The groups were matched for clinical characteristics, risk factors and baseline haemodynamics. Myocardial blood flow (MBF) and myocardial flow reserve (MFR) were quantified using a previously validated retention model, after resampling of dynamic studies from list-mode 82 Rb datasets. At rest, heart rate, blood pressure and MBF were comparable between the groups. Regadenoson resulted in a significantly higher heart rate (34 ± 14 vs. 23 ± 10 beats per minute increase from baseline; p < 0.01) and rate-pressure product. Patients in the regadenoson group reported less severe symptoms and required less aminophylline. Stress MBF and MFR were not different between the groups (2.2 ± 0.6 vs. 2.1 ± 0.6 ml/min/g, p = 0.39, and 2.9 ± 0.8 vs. 2.8 ± 0.7, p = 0.31, respectively). In the regadenoson group, there was no correlation between stress flow or MFR and body weight or BMI. Despite its administration at a fixed dose, regadenoson results in an absolute increase in MBF which is comparable to that

  9. Hypertension impairs myocardial blood perfusion reserve in subjects without regional myocardial ischemia

    International Nuclear Information System (INIS)

    Nakajima, Hiroshi; Onishi, Katsuya; Kurita, Tairo

    2010-01-01

    Quantitative analysis of myocardial perfusion MRI can provide noninvasive assessments of myocardial perfusion reserve (MPR), which is associated with endothelial function. Endothelial function is influenced by various factors, including hypertension, diabetes, dyslipidemia, renal dysfunction and anemia. The purpose of this study was to evaluate which risk factor is the strongest effector of MPR in subjects without regional myocardial ischemia. We studied 110 patients (66 years ±10, male 68%, hypertension 76%, diabetes mellitus (DM) 40% and dyslipidemia 65%) without regional myocardial ischemia. Adenosine triphosphate (ATP) stress and rest first-pass perfusion magnetic resonance (MR) images were acquired with a 1.5-T MR system, and MPR was calculated as the ratio of stress to rest myocardial blood flow (MBF). Average rest MBF in 110 patients was 1.07±0.62 ml min -1 g -1 , whereas stress MBF was 3.15±1.93 ml min -1 g -1 and the MPR was 3.33±1.82. Rest MBF correlated significantly with hematocrit, whereas stress MBF showed a strong correlation with estimated glomerular filtration rate (e-GFR). MPR was associated with hypertension, age, e-GFR, hematocrit and left ventricular mass index (LVMI). In multiple regression analysis, hypertension (P=0.003, β=-0.274) showed the strongest correlation with MPR among other risk factors, such as diabetes (P=ns), dyslipidemia (P=ns), e-GFR (P=ns), LVMI (P=0.007, β=-0.248) and hematocrit (P=ns) after adjusting age and gender. Hypertension is the most important effector of MPR in subjects without myocardial ischemia. (author)

  10. Hypertension impairs myocardial blood perfusion reserve in subjects without regional myocardial ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Hiroshi; Onishi, Katsuya; Kurita, Tairo [Mie Univ., Graduate School of Medicine, Tsu, Mie (Japan)

    2010-11-15

    Quantitative analysis of myocardial perfusion MRI can provide noninvasive assessments of myocardial perfusion reserve (MPR), which is associated with endothelial function. Endothelial function is influenced by various factors, including hypertension, diabetes, dyslipidemia, renal dysfunction and anemia. The purpose of this study was to evaluate which risk factor is the strongest effector of MPR in subjects without regional myocardial ischemia. We studied 110 patients (66 years {+-}10, male 68%, hypertension 76%, diabetes mellitus (DM) 40% and dyslipidemia 65%) without regional myocardial ischemia. Adenosine triphosphate (ATP) stress and rest first-pass perfusion magnetic resonance (MR) images were acquired with a 1.5-T MR system, and MPR was calculated as the ratio of stress to rest myocardial blood flow (MBF). Average rest MBF in 110 patients was 1.07{+-}0.62 ml min{sup -1} g{sup -1}, whereas stress MBF was 3.15{+-}1.93 ml min{sup -1} g{sup -1} and the MPR was 3.33{+-}1.82. Rest MBF correlated significantly with hematocrit, whereas stress MBF showed a strong correlation with estimated glomerular filtration rate (e-GFR). MPR was associated with hypertension, age, e-GFR, hematocrit and left ventricular mass index (LVMI). In multiple regression analysis, hypertension (P=0.003, {beta}=-0.274) showed the strongest correlation with MPR among other risk factors, such as diabetes (P=ns), dyslipidemia (P=ns), e-GFR (P=ns), LVMI (P=0.007, {beta}=-0.248) and hematocrit (P=ns) after adjusting age and gender. Hypertension is the most important effector of MPR in subjects without myocardial ischemia. (author)

  11. Reverse redistribution phenomenon on rest 99mTc-tetrofosmin myocardial single photon emission computed tomography involves impaired left ventricular contraction in patients with acute myocardial infarction

    International Nuclear Information System (INIS)

    Kurokawa, Kazuyuki; Ohte, Nobuyuki; Miyabe, Hiromichi; Akita, Sachie; Yajima, Kazuhiro; Hayano, Junichiro; Kimura, Genjiro

    2003-01-01

    The purpose of this study was to investigate the clinical significance of the reverse redistribution (RR) phenomenon on technetium-99m ( 99m Tc)-tetrofosmin myocardial single photon emission computed tomography (SPECT) performed at rest. Twenty-five patients underwent myocardial SPECT 3 weeks after the onset of acute myocardial infarction. Myocardial images were acquired at 40 min (early) and 4 h (delayed) after the injection of 740 MBq of 99m Tc-tetrofosmin. The regional myocardial uptake of the tracer in 26 segments of the left ventricular (LV) wall was visually scored from 0 (no activity) to 3 (normal activity), and then the RR was defined as a decrease of more than 1 point in the activity score on the delayed image compared with that on the early image. Regions with an activity score of 3 on both the early and delayed images were defined as normal, and those with a score of 0 or 1 on the early image were considered to have a fixed defect. The regional myocardial 99m Tc-tetrofosmin uptake and washout rate were also quantitatively assessed in each region. In addition, exercise stress electrocardiograph-gated SPECT with 99m Tc-tetrofosmin was performed within 1 week of the rest study, and the percent count increase (%CI) during myocardial contraction in each corresponding region was studied. RR was observed in 18 of the 25 patients. The regional washout rate of 99m Tc-tetrofosmin was significantly higher in the RR regions (45.0±3.8%) than in either the normal regions (36.4±4.1%, p 99m Tc-tetrofosmin SPECT have severely impaired LV wall contraction after exercise. (author)

  12. Normal Myocardial Flow Reserve in HIV-Infected Patients on Stable Antiretroviral Therapy

    DEFF Research Database (Denmark)

    Knudsen, Andreas; Christensen, Thomas E; Ghotbi, Adam Ali

    2015-01-01

    . The HIV-infected patients had a mean age of 53 years (range 37-68 years) with 23% active smokers. The controls had a mean age of 52 years (range 36-68 years) and 26% active smokers. In the HIV-infected group 73% had a normal MFR, 17% borderline, and 10% low values of MFR. Among controls these values were...... 71%, 19%, and 10%, respectively (P = 0.99). However, the HIV-infected group had lower values of stress myocardial blood flow (MBF) (2.63 ± 0.09 mL/g/min vs 2.99 ± 0.14 mL/g/min; P = 0.03). We found no evidence of decreased MFR as assessed by 82Rb PET among HIV-infected patients on stable ART...

  13. Variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects

    DEFF Research Database (Denmark)

    Kofoed, Klaus F; Hove, Jens D; Freiberg, Jacob

    2002-01-01

    The aim of this study was to assess regional and global variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects and to evaluate potentially responsible factors. Twenty men with a mean age of 64 years, no history of cardiovascular disease, and normal blood pressure...... rest and hyperaemic blood flow during dipyridamole infusion were measured with nitrogen-13 ammonia and positron emission tomography in 16 left ventricular myocardial segments. Intra-individual and inter-individual variability of insulin-stimulated myocardial glucose uptake [relative dispersion...... = (standard deviation/mean)] was 13% and 29% respectively. Although inter-individual variability of glucose uptake and blood flow at rest was of the same magnitude, no correlation was found between these measures. Regional and global insulin-stimulated myocardial glucose uptake correlated linearly with whole...

  14. Using the tracer-dilution discharge method to develop streamflow records for ice-affected streams in Colorado

    Science.gov (United States)

    Capesius, Joseph P.; Sullivan, Joseph R.; O'Neill, Gregory B.; Williams, Cory A.

    2005-01-01

    Accurate ice-affected streamflow records are difficult to obtain for several reasons, which makes the management of instream-flow water rights in the wintertime a challenging endeavor. This report documents a method to improve ice-affected streamflow records for two gaging stations in Colorado. In January and February 2002, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, conducted an experiment using a sodium chloride tracer to measure streamflow under ice cover by the tracer-dilution discharge method. The purpose of this study was to determine the feasibility of obtaining accurate ice-affected streamflow records by using a sodium chloride tracer that was injected into the stream. The tracer was injected at two gaging stations once per day for approximately 20 minutes for 25 days. Multiple-parameter water-quality sensors at the two gaging stations monitored background and peak chloride concentrations. These data were used to determine discharge at each site. A comparison of the current-meter streamflow record to the tracer-dilution streamflow record shows different levels of accuracy and precision of the tracer-dilution streamflow record at the two sites. At the lower elevation and warmer site, Brandon Ditch near Whitewater, the tracer-dilution method overestimated flow by an average of 14 percent, but this average is strongly biased by outliers. At the higher elevation and colder site, Keystone Gulch near Dillon, the tracer-dilution method experienced problems with the tracer solution partially freezing in the injection line. The partial freezing of the tracer contributed to the tracer-dilution method underestimating flow by 52 percent at Keystone Gulch. In addition, a tracer-pump-reliability test was conducted to test how accurately the tracer pumps can discharge the tracer solution in conditions similar to those used at the gaging stations. Although the pumps were reliable and consistent throughout the 25-day study period

  15. Myocardial blood flow and V/sub O2/ in conscious lambs with an aortopulmonary shunt

    International Nuclear Information System (INIS)

    Toorop, G.P.; Hardjowijono, R.; Dalinghaus, M.; Gerding, A.M.; Koers, J.H.; Zijlstra, W.G.; Kuipers, J.R.G.

    1987-01-01

    The authors measured myocardial blood flow (q/sub LVFW/) using radioactively-labeled microspheres and O 2 consumption of the left ventricular free wall (V/sub O 2 , LVFW/) in 13 chronically instrumented, 7-wk-old lambs with an aortopulmonary left-to-right shunt (S) and in 10 control lamps without a shunt (C). The measured V/sub O 2 , LVFW/ was compared with the calculated values obtained by two predictive indexes, the rate-pressure product (RPP) and the pressure-work index (PWI). Measured V/sub O 2 , LVFW/ in S lambs was significantly higher than in C lambs. This was achieved by the significantly higher q/sub LVFW/, since the arteriovenous O 2 difference across the left ventricular free wall was similar in both groups of lambs. Total coronary blood flow per unit body mass in S lambs was higher than in C lambs, not only because of the increased V/sub O 2 , LVFW/ per unit muscle mass, but also because of the increased total heart weight. Correct estimation of V/sub O 2 /, LVFW/ by means of the RPP and the PWI was only possible in C lambs. In S lambs the estimated values were significantly lower than the measured ones. They conclude that since V/sub O 2 , LVFW/ in S lambs is twice as high as in C lambs, the data support the view that a volume load caused by a left-to-right shunt may have a more profound effect on myocardial O 2 consumption than could be anticipated on the basis of previous work

  16. Noninvasive quantification of regional myocardial perfusion with rubidium-82 and positron emission tomography. Exploration of a mathematical model

    International Nuclear Information System (INIS)

    Herrero, P.; Markham, J.; Shelton, M.E.; Weinheimer, C.J.; Bergmann, S.R.

    1990-01-01

    Positron emission tomography (PET) centers without cyclotrons use generator-produced rubidium-82 (82Rb) for assessment of myocardial perfusion. The aim of the present study was to determine whether myocardial blood flow could be assessed quantitatively with 82Rb and PET. Because the myocardial extraction fraction of 82Rb varies inversely and nonlinearly with flow and cannot be measured conveniently with PET, we used an experimentally derived mathematical function defining the relation between single-pass extraction fraction of 82Rb and flow to obviate the necessity of measuring the extraction fraction directly. Myocardial blood flow in absolute terms (ml/g/min) was estimated from dynamic PET scans after intravenous administration of 82Rb in intact dogs and compared with flows measured with radiolabeled microspheres. In 36 comparisons in 13 dogs studied at rest, or after coronary occlusion, reperfusion, or after coronary hyperemia induced with intravenous dipyridamole, over the flow range from 0.2 to 2.0 ml/g/min, estimates of perfusion with rubidium correlated well with flows measured concomitantly with microspheres, although there was a slight underestimation of flow with rubidium (flow by 82Rb = 0.92 x flow by microspheres-0.021, r = 0.83). In general, estimates of flow in ischemic regions were less reliable than estimates for regions with normal flow. Thus, although the relation between myocardial extraction and retention of 82Rb and flow can vary under a variety of physiological and pathophysiological conditions, this study demonstrates the ability to obtain quantitative estimates of myocardial blood flow with 82Rb and PET under carefully defined conditions without measuring the extraction fraction directly

  17. Myocardial blood flow quantification by Rb-82 cardiac PET/CT: A detailed reproducibility study between two semi-automatic analysis programs.

    Science.gov (United States)

    Dunet, Vincent; Klein, Ran; Allenbach, Gilles; Renaud, Jennifer; deKemp, Robert A; Prior, John O

    2016-06-01

    Several analysis software packages for myocardial blood flow (MBF) quantification from cardiac PET studies exist, but they have not been compared using concordance analysis, which can characterize precision and bias separately. Reproducible measurements are needed for quantification to fully develop its clinical potential. Fifty-one patients underwent dynamic Rb-82 PET at rest and during adenosine stress. Data were processed with PMOD and FlowQuant (Lortie model). MBF and myocardial flow reserve (MFR) polar maps were quantified and analyzed using a 17-segment model. Comparisons used Pearson's correlation ρ (measuring precision), Bland and Altman limit-of-agreement and Lin's concordance correlation ρc = ρ·C b (C b measuring systematic bias). Lin's concordance and Pearson's correlation values were very similar, suggesting no systematic bias between software packages with an excellent precision ρ for MBF (ρ = 0.97, ρc = 0.96, C b = 0.99) and good precision for MFR (ρ = 0.83, ρc = 0.76, C b = 0.92). On a per-segment basis, no mean bias was observed on Bland-Altman plots, although PMOD provided slightly higher values than FlowQuant at higher MBF and MFR values (P < .0001). Concordance between software packages was excellent for MBF and MFR, despite higher values by PMOD at higher MBF values. Both software packages can be used interchangeably for quantification in daily practice of Rb-82 cardiac PET.

  18. Myocardial ischemia in hypertrophic cardiomyopathy; Isquemia miocardica na cardiomiopatia hipertrofica

    Energy Technology Data Exchange (ETDEWEB)

    Lima Filho, Moyses de Oliveira; Figueiredo, Geraldo L.; Simoes, Marcus V.; Pyntia, Antonio O.; Marin Neto, Jose Antonio [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Div. de Cardiologia

    2000-08-01

    Myocardial ischemia in hypertrophic cardiomyopathy is multifactorial and explains the occurrence of angina, in about 50% of patients. The pathophysiology of myocardial ischemia may be explained by the increase of the ventricular mass and relative paucity of the coronary microcirculation; the elevated ventricular filling pressures and myocardial stiffness causing a compression of the coronary microvessels; the impaired coronary vasodilator flow reserve caused by anatomic and functional abnormalities; and the systolic compression of epicardial vessel (myocardial bridges). Myocardial ischemia must be investigated by perfusion scintigraphic methods since its presence influences the prognosis and has relevant clinical implications for management of patients. Patients with hypertrophic cardiomyopathy and documented myocardial ischemia usually need to undergo invasive coronary angiography to exclude the presence of concomitant atherosclerotic coronary disease. (author)

  19. Coronary grafts flow and cardiac pacing modalities: how to improve perioperative myocardial perfusion.

    LENUS (Irish Health Repository)

    D'Ancona, Giuseppe

    2012-02-03

    OBJECTIVE: Aim of this study was to investigate modifications of coronary grafts flow during different pacing modalities after CABG. MATERIALS AND METHODS: Two separate prospective studies were conducted in patients undergoing CABG and requiring intraoperative epicardial pacing. In a first study (22 patients) coronary grafts flows were measured during dual chamber pacing (DDD) and during ventricular pacing (VVI). In a second study (10 patients) flows were measured during DDD pacing at different atrio-ventricular (A-V) delay periods. A-V delay was adjusted in 25 ms increments from 25 to 250 ms and flow measurements were performed for each A-V delay increment. A transit time flowmeter was used for the measurements. RESULTS: An average of 3.4 grafts\\/patient were performed. In the first study, average coronary graft flow was 47.4+\\/-20.8 ml\\/min during DDD pacing and 41.8+\\/-18.2 ml\\/min during VVI pacing (P = 0.0004). Furthermore average systolic pressure was 94.3+\\/-10.1 mmHg during DDD pacing and 89.6+\\/-12.2 mmHg during VVV pacing (P = 0.0007). No significant differences in diastolic pressure were recorded during the two different pacing modalities. In the second study, maximal flows were achieved during DDD pacing with an A-V delay of 175 ms (54+\\/-9.6 ml\\/min) and minimal flows were detected at 25 ms A-V delay (38.1+\\/-4.7 ml\\/min) (P=ns). No significant differences in systolic or diastolic blood pressure were noticed during the different A-V delays. CONCLUSION: Grafts flowmetry provides an extra tool to direct supportive measures such as cardiac pacing after CABG. DDD mode with A-V delay around 175 ms. should be preferred to allow for maximal myocardial perfusion via the grafts.

  20. High dose naloxone does not improve cerebral or myocardial blood flow during cardiopulmonary resuscitation in pigs.

    Science.gov (United States)

    Gervais, H W; Eberle, B; Hennes, H J; Grimm, W; Kilian, A; Konietzke, D; Massing, C; Dick, W

    1997-06-01

    In a prospective, randomized, placebo-controlled, double-blind trial we tested the hypothesis that naloxone given during cardiopulmonary resuscitation (CPR) enhances cerebral and myocardial blood flow. Twenty-one anesthetized, normoventilated pigs were instrumented for measurements of right atrial and aortic pressures, and regional organ blood flow (radiolabeled microspheres). After 5 min of untreated fibrillatory arrest, CPR was commenced using a pneumatic chest compressor/ventilator. With onset of CPR, an i.v. bolus of 40 micrograms/kg b.w. of epinephrine was given, followed by an infusion of 0.4 micrograms/kg per min. After 5 min of CPR, either naloxone, 10 mg/kg b.w. (group N, n = 11) or normal saline (group S, n = 10) was given i.v. Prior to, and after 1, 15, and 30 min of CPR, hemodynamic and blood flow measurements were obtained. After 30 min of CPR, mean arterial pressure was significantly higher in group N (26 +/- 5 vs. 13 +/- 3 mmHg, P CPR.

  1. Assessment of endothelial function and myocardial flow reserve using {sup 15}O-water PET without attenuation correction

    Energy Technology Data Exchange (ETDEWEB)

    Tuffier, Stephane; Joubert, Michael; Bailliez, Alban [EA 4650, Normandie Universite, Caen (France); Legallois, Damien [EA 4650, Normandie Universite, Caen (France); Caen University Hospital, Department of Cardiology, Caen (France); Belin, Annette [Caen University Hospital, Department of Cardiac Surgery, Caen (France); Redonnet, Michel [Rouen University Hospital, Department of Cardiac Surgery, Rouen (France); Agostini, Denis [EA 4650, Normandie Universite, Caen (France); Caen University Hospital, Department of Nuclear Medicine, Caen (France); Manrique, Alain [EA 4650, Normandie Universite, Caen (France); Caen University Hospital, Department of Nuclear Medicine, Caen (France); Cyceron PET Centre, Caen (France)

    2016-02-15

    Myocardial blood flow (MBF) measurement using positron emission tomography (PET) from the washout rate of {sup 15}O-water is theoretically independent of tissue attenuation. The aim of this study was to evaluate the impact of not using attenuation correction in the assessment of coronary endothelial function and myocardial flow reserve (MFR) using {sup 15}O-water PET. We retrospectively processed 70 consecutive {sup 15}O-water PET examinations obtained at rest and during cold pressor testing (CPT) in patients with dilated cardiomyopathy (n = 58), or at rest and during adenosine infusion in heart transplant recipients (n = 12). Data were reconstructed with attenuation correction (AC) and without attenuation correction (NAC) using filtered backprojection, and MBF was quantified using a single compartmental model. The agreement between AC and NAC data was assessed using Lin's concordance correlation coefficient followed by Bland-Altman plot analysis. Regarding endothelial function, NAC PET showed poor reproducibility and poor agreement with AC PET data. Conversely, NAC PET demonstrated high reproducibility and a strong agreement with AC PET for the assessment of MFR. Non-attenuation-corrected {sup 15}O-water PET provided an accurate measurement of MFR compared to attenuation-corrected PET. However, non-attenuation-corrected PET data were less effective for the assessment of endothelial function using CPT in this population. (orig.)

  2. Concepts of flow in fractured rocks

    International Nuclear Information System (INIS)

    Black, J.H.

    1989-01-01

    The role of well testing is considered in the context of tracer tests in fractured rock. It is shown that the important information required by a tracer test includes not just the hydrogeological parameters (transmissivity and storage), but also the geometry of flow. This is usually implicit in well testing, perhaps because the tests are generally interpretationally insensitive to variations in flow geometry. It is also argued that both well and tracer tests change their flow geometry during their lifetime. They often start as pipe flow near a well and change to large scale, almost spherical, flow after long periods of time. The duration of a tracer test is compared with that of a well test and is found to reach an equivalent duration (of dimensionless time) that is at least 10 4 times longer. Care should be exercised in transposing flow geometries derived from mature well tests on to tracer tests which are not similar in dimensionless time. Finally, a 'sinusoidal flow test' is outlined which has prompted a new way of looking at well tests in terms of their flow geometry. The new analysis involves 'partial dimension' of flow and is probably highly appropriate to fissured rocks. Fissured rocks have, for too long, been seen as a regular system of planar, fully transmissive fissures. (author). 12 refs, 4 figs, 1 tab

  3. Estimation of myocardial flow reserve utilizing an ultrafast cardiac SPECT: Comparison with coronary angiography, fractional flow reserve, and the SYNTAX score.

    Science.gov (United States)

    Miyagawa, Masao; Nishiyama, Yoshiko; Uetani, Teruyoshi; Ogimoto, Akiyoshi; Ikeda, Shuntaro; Ishimura, Hayato; Watanabe, Emiri; Tashiro, Rami; Tanabe, Yuki; Kido, Teruhito; Kurata, Akira; Mochizuki, Teruhito

    2017-10-01

    Quantitative assessment of myocardial flow reserve (MFR) by single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is challenging but may facilitate evaluation of multi-vessel coronary artery disease (CAD). We enrolled 153 patients with suspected or known CAD, referred for pharmacological stress MPI. They underwent a 99m Tc-perfusion stress/rest SPECT with an ultrafast cadmium-zinc-telluride (CZT) camera. Dynamic data were acquired and time-activity curves fitted to a 1-tissue compartment analysis with input function. K1 was assigned for stress and rest data. The MFR index (MFRi) was calculated as K1 stress/K1 at-rest. The findings were validated by invasive coronary angiography in 69 consecutive patients. The global MFRi was 1.46 (1.16-1.76), 1.33 (1.12-1.54), and 1.18 (1.01-1.35), for 1-vessel disease (VD), 2-VD, and 3-VD, respectively. In the 3-VD, global MFRi was lower than that in 0-VD (1.63 [1.22-2.04], Pfraction (OR: 61.6 [57.5-66.0]), and global MFRi (OR: 119.6 [111.5-127.7], P=0.002). A cut-off value of 1.3 yielded 93.3% sensitivity and 75.9% specificity for diagnosing 3-VD. Fractional flow reserve positively correlated with regional MFRi (r=0.62, P=0.008), and the SYNTAX score correlated negatively with global MFRi (r=0.567, P=0.0003). We developed and validated a clinically available method for MFR quantification by dynamic 99m Tc-perfusion SPECT utilizing a CZT camera, which improves the detectability of multi-vessel CAD. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Comparison of the myocardial blood flow response to regadenoson and dipyridamole: a quantitative analysis in patients referred for clinical {sup 82}Rb myocardial perfusion PET

    Energy Technology Data Exchange (ETDEWEB)

    Goudarzi, Behnaz; Fukushima, Kenji; Bravo, Paco; Merrill, Jennifer [Johns Hopkins University, Division of Nuclear Medicine, Russell H Morgan Department of Radiology, Baltimore, MD (United States); Bengel, Frank M. [Johns Hopkins University, Division of Nuclear Medicine, Russell H Morgan Department of Radiology, Baltimore, MD (United States); Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany)

    2011-10-15

    Regadenoson is a novel selective A{sub 2A} adenosine receptor agonist, which is administered as an intravenous bolus at a fixed dose. It is currently not clear if the absolute flow increase in response to this fixed dose is a function of distribution volume in individual patients or if it is generally comparable to the previous standard agents dipyridamole or adenosine, which are dosed based on weight. We used quantitative analysis of clinical {sup 82}Rb PET/CT studies to obtain further insights. A total of 104 subjects with normal clinical rest/stress {sup 82}Rb perfusion PET/CT were included in a retrospective analysis. To rule out confounding factors, none had evidence of prior cardiac disease, ischaemia or infarction, cardiomyopathy, diabetes with insulin use, calcium score >400, renal disease or other significant systemic disease. A group of 52 patients stressed with regadenoson were compared with a group of 52 patients stressed with dipyridamole before regadenoson became available. The groups were matched for clinical characteristics, risk factors and baseline haemodynamics. Myocardial blood flow (MBF) and myocardial flow reserve (MFR) were quantified using a previously validated retention model, after resampling of dynamic studies from list-mode {sup 82}Rb datasets. At rest, heart rate, blood pressure and MBF were comparable between the groups. Regadenoson resulted in a significantly higher heart rate (34 {+-} 14 vs. 23 {+-} 10 beats per minute increase from baseline; p < 0.01) and rate-pressure product. Patients in the regadenoson group reported less severe symptoms and required less aminophylline. Stress MBF and MFR were not different between the groups (2.2 {+-} 0.6 vs. 2.1 {+-} 0.6 ml/min/g, p = 0.39, and 2.9 {+-} 0.8 vs. 2.8 {+-} 0.7, p = 0.31, respectively). In the regadenoson group, there was no correlation between stress flow or MFR and body weight or BMI. Despite its administration at a fixed dose, regadenoson results in an absolute increase in MBF

  5. Left Ventricular Myocardial Deformation Parameters Are Affected by Coronary Slow Flow Phenomenon: A Study of Speckle Tracking Echocardiography.

    Science.gov (United States)

    Gulel, Okan; Akcay, Murat; Soylu, Korhan; Aksan, Gokhan; Yuksel, Serkan; Zengin, Halit; Meric, Murat; Sahin, Mahmut

    2016-05-01

    The coronary slow flow phenomenon (CSFP) is defined as a delayed distal vessel contrast opacification in the absence of obstructive epicardial coronary artery disease during coronary angiography. There is conflicting data in medical literature regarding the effects of CSFP on the left ventricular functions assessed by conventional echocardiography or tissue Doppler imaging. Therefore, we aimed to evaluate whether there is any abnormality in the myocardial deformation parameters (strain, strain rate (SR), rotation, twist) of the left ventricle obtained by speckle tracking echocardiography (STE) in patients with CSFP. Twenty patients with CSFP were included prospectively in the study. Another 20 patients with similar demographics and cardiovascular risk factors as well as normal coronary angiography were used as the control group. Two-dimensional echocardiographic images of the left ventricle from the apical long-axis, two-chamber, four-chamber, and parasternal short-axis views were used for STE analysis. The analysis of left ventricular circumferential deformation parameters showed that the averaged peak systolic strain, systolic SR, and early diastolic SR values were significantly lower in patients with CSFP (P = 0.009, P = 0.02, and P = 0.02, respectively). Among the left ventricular rotation and twist values, apical rotation was significantly lower in patients with CSFP (P = 0.02). Further, the mean thrombolysis in myocardial infarction frame count value was found to be negatively correlated with the averaged peak circumferential early diastolic SR (r = -0.35, P = 0.03). It was positively correlated with the averaged peak circumferential systolic strain (r = 0.47, P = 0.003) and circumferential systolic SR (r = 0.46, P = 0.005). Coronary slow flow phenomenon leads to significant alterations in the myocardial deformation parameters of the left ventricle as assessed by STE. Specifically, circumferential deformation parameters are affected in CSFP patients. © 2015

  6. Investigation of intrarenal blood flow and urine flow aspects by scintillation camera

    International Nuclear Information System (INIS)

    Kawamura, J.; Hosokawa, S.; Yoshida, O.; Ishii, Y.; Torizuka, K.

    1977-01-01

    In order to clarify intrarenal dynamic processes related to regional distribution in patients with unilateral renal disease, two radioactive tracers, 133 Xe and /sup 99m/Tc-diethylenetriaminepentaacetic acid (/sup 99m/Tc-DTPA) were introduced into a renal artery and intrarenal blood flow and urine flow aspects were observed by scintillation camera. Cortical blood flow decreased and medullary blood flow relatively increased with the advance of renal damage. Urine flow curve from normal cortex showed two phasic patterns. One early phase might correspond to the appearance of the tracer through the proximal tubule and a second phase might correspond to the appearance of the tracer through the loop of Henle to the distal tubule. Under mannitol diuresis, two phasic urine flow curves from the cortex became obscured and the peak time of pelvic curve shifted to the earlier period. These studies were considered to be useful in evaluating unilateral renal function and might offer a good insight for intrarenal physiology concerning blood flow as well as urine flow

  7. Innovative use of a microbial tracer for measuring groundwater through a fractured matrix

    International Nuclear Information System (INIS)

    Strong-Gunderson, J.M.

    1995-01-01

    Site characterization for ground water remediation activities is limited by the one's ability to visualize the complexity of the subsurface environment. Currently, a variety of dyes, colloids, gases, etc., are used to monitor and estimate ground water flow and contaminant transport. The author has recently identified a new, innovative colloidal tracer that is a non-hazardous bacterium that is detectable at very low concentrations (ng/kg), and can provide real-time analysis (3--5 min) for measuring colloid transport. The tracer is the ice nucleating active (INA) bacterium Pseudomonas syringae. The assay conditions require measuring the freezing point of the sample (e.g., ground water and soil slurries). Typically, 10--100 microL drops of water will not freeze until -15 to -20 C. However, if the tracer is present the water will freeze at -3 to -7 C. This increase in the freezing point can only be due to the presence of the tracer and this phenomenon is well documented in the plant pathology and low-temperature biology literature but has only now been applied to site characterization and remediation activities. Laboratory experiments have identified the stability of the tracer in the presence of a variety of ground water contaminants (> 100 ppm) and it is stable over a pH range of 2.3--10.0. The tracer has been demonstrated in conjunction with other commonly used tracers at a variety of field sites: (1) a drilling tracer to identify potential cross contamination, and as a colloid/bacterial tracer in (2) a hydrofracturing demonstration, (3) a horizontal recirculation well system, (4) a fractured karst matrix, and (5) a radioactive contaminated site. The data from these demonstrations have provided additional information about site characteristics including faster ground water flow rates than previously identified and due to its low sensitivities better distribution into a clay matrix than estimated by the bromide tracer

  8. Fluorescence tracers as a reference for pesticide transport in wetland systems

    Science.gov (United States)

    Lange, Jens; Passeport, Elodie; Tournebize, Julien

    2010-05-01

    Two different fluorescent tracers, Uranine (UR) and Sulforhodamine (SRB), were injected as a pulse into surface flow wetlands. Tracer breakthrough curves were used to document hydraulic efficiencies, peak attenuation and retention capacities of completely different wetland systems. The tracers were used as a reference to mimic photolytic decay (UR) and sorption (SRB) of contaminants, since a real herbicide (Isoproturon, IPU) was injected in parallel to UR and SRB. Analysis costs limited IPU sampling frequency and single samples deviated from the tracer breakthrough curves. Still, a parallel behavior of IPU and SRB could be observed in totally different wetland systems, including underground passage through drainage lines. Similar recovery rates for IPU and SRB confirmed this observation. Hence, SRB was found to be an appropriate reference tracer to mimic the behavior of mobile pesticides (low KOC, without degradation) in wetland systems and the obtained wetland characteristics for SRB may serve as an indication for contaminant retention. Owing to the properties of IPU, the obtained results should be treated as worst case scenarios for highly mobile pesticides. A comparison of six different wetland types suggested that non-steady wetland systems with large variation in water level may temporally store relatively large amounts of tracers (contaminants), partly in areas that are not continuously saturated. This may lead to an efficient attenuation of peak concentrations. However, when large parts of these systems are flushed by natural storm events, tracers (contaminants) may be re-mobilized. In steady systems vegetation density and water depth were found to be the most important factors for tracer/contaminant retention. Illustrated by SRB, sorption on sediments and vegetation was a quick, almost instantaneous process which lead to considerable tracer losses even at high flow velocities and short contact times. Shallow systems with dense vegetation appeared to be the

  9. Tracer transport in fractures: analysis of field data based on a variable - aperture channel model

    International Nuclear Information System (INIS)

    Tsang, C.F.; Tsang, Y.W.; Hale, F.V.

    1991-06-01

    A variable-aperture channel model is used as the basis to interpret data from a three-year tracer transport experiment in fractured rocks. The data come from the so-called Stripa-3D experiment performed by Neretnieks and coworkers. Within the framework of the variable-aperture channel conceptual model, tracers are envisioned as travelling along a number of variable-aperture flow channels, whose properties are related to the mean b - and standard deviation σ b of the fracture aperture distribution. Two methods are developed to address the presence of strong time variation of the tracer injection flow rate in this experiment. The first approximates the early part of the injection history by an exponential decay function and is applicable to the early time tracer breakthrough data. The second is a deconvolution method involving the use of Toeplitz matrices and is applicable over the complete period of variable injection of the tracers. Both methods give consistent results. These results include not only estimates of b and σ, but also ranges of Peclet numbers, dispersivity and an estimate of the number of channels involved in the tracer transport. An interesting and surprising observation is that the data indicate that the Peclet number increases with the mean travel time: i.e., dispersivity decreasing with mean travel time. This trend is consistent with calculated results of tracer transport in multiple variable-aperture fractures in series. The meaning of this trend is discussed in terms of the strong heterogeneity of the flow system. (au) (22 refs.)

  10. The role of PET quantification in cardiovascular imaging.

    Science.gov (United States)

    Slomka, Piotr; Berman, Daniel S; Alexanderson, Erick; Germano, Guido

    2014-08-01

    Positron Emission Tomography (PET) has several clinical and research applications in cardiovascular imaging. Myocardial perfusion imaging with PET allows accurate global and regional measurements of myocardial perfusion, myocardial blood flow and function at stress and rest in one exam. Simultaneous assessment of function and perfusion by PET with quantitative software is currently the routine practice. Combination of ejection fraction reserve with perfusion information may improve the identification of severe disease. The myocardial viability can be estimated by quantitative comparison of fluorodeoxyglucose ( 18 FDG) and rest perfusion imaging. The myocardial blood flow and coronary flow reserve measurements are becoming routinely included in the clinical assessment due to enhanced dynamic imaging capabilities of the latest PET/CT scanners. Absolute flow measurements allow evaluation of the coronary microvascular dysfunction and provide additional prognostic and diagnostic information for coronary disease. Standard quantitative approaches to compute myocardial blood flow from kinetic PET data in automated and rapid fashion have been developed for 13 N-ammonia, 15 O-water and 82 Rb radiotracers. The agreement between software methods available for such analysis is excellent. Relative quantification of 82 Rb PET myocardial perfusion, based on comparisons to normal databases, demonstrates high performance for the detection of obstructive coronary disease. New tracers, such as 18 F-flurpiridaz may allow further improvements in the disease detection. Computerized analysis of perfusion at stress and rest reduces the variability of the assessment as compared to visual analysis. PET quantification can be enhanced by precise coregistration with CT angiography. In emerging clinical applications, the potential to identify vulnerable plaques by quantification of atherosclerotic plaque uptake of 18 FDG and 18 F-sodium fluoride tracers in carotids, aorta and coronary arteries

  11. Ratio of left ventricular peak E-wave velocity to flow propagation velocity assessed by color M-mode Doppler echocardiography in first myocardial infarction

    DEFF Research Database (Denmark)

    Møller, J E; Søndergaard, E; Seward, J B

    2000-01-01

    OBJECTIVES: To determine the ability of the ratio of peak E-wave velocity to flow propagation velocity (E/Vp) measured with color M-mode Doppler echocardiography to predict in-hospital heart failure and cardiac mortality in an unselected consecutive population with first myocardial infarction (MI...

  12. Tracer verification and monitoring of containment systems (II)

    International Nuclear Information System (INIS)

    Williams, C.V.; Dunn, S.D.; Lowry, W.E.

    1997-01-01

    A tracer verification and monitoring system, SEAtrace trademark, has been designed and field tested which uses gas tracers to evaluate, verify, and monitor the integrity of subsurface barriers. This is accomplished using an automatic, rugged, autonomous monitoring system combined with an inverse optimization code. A gaseous tracer is injected inside the barrier and an array of wells outside the barrier are monitored. When the tracer gas is detected, a global optimization code is used to calculate the leak parameters, including leak size, location, and when the leak began. The multipoint monitoring system operates in real-time, can be used to measure both the tracer gas and soil vapor contaminants, and is capable of unattended operation for long periods of time (months). The global optimization code searches multi-dimensional open-quotes spaceclose quotes to find the best fit for all of the input parameters. These parameters include tracer gas concentration histories from multiple monitoring points, medium properties, barrier location, and the source concentration. SEAtrace trademark does not attempt to model all of the nuances associated with multi-phase, multi-component flow, but rather, the inverse code uses a simplistic forward model which can provide results which are reasonably accurate. The system has calculated leak locations to within 0.5 meters and leak radii to within 0.12 meters

  13. Regional wall thickening in gated myocardial perfusion SPECT in a Japanese population: effect of sex, radiotracer, rotation angles and frame rates

    Energy Technology Data Exchange (ETDEWEB)

    Akhter, Nasima; Nakajima, Kenichi; Okuda, Koichi; Matsuo, Shinro; Yoneyama, Tatsuya; Taki, Junichi; Kinuya, Seigo [Kanazawa University Hospital, Department of Nuclear Medicine, Kanazawa, Ishikawa (Japan)

    2008-09-15

    Gated single-photon emission computed tomography (SPECT) imaging of myocardium by {sup 99m}Tc and {sup 201}Tl is used extensively to measure quantitative cardiac functional parameters. However, factors affecting normal values for myocardial functional parameters and population-specific standards have not yet been established. The aim of the study was to determine the effect of sex, radiotracer, rotation angles and frame rates on resting myocardial wall thickening (WT) and to develop a Japanese standard of normal values for WT. Data from a total of 202 patients with low possibility of having cardiac problems were collected from nine hospitals throughout Japan. Patients were divided into five groups according to study protocol, and WT was evaluated according to the 17-segment and four-region (basal, mid and apical regions and the apex) polar map distribution. WT was generally higher in women than in men irrespective of the use of radiotracers, rotation angles or frame rates, and the difference was highly significant in the mid and apical regions. In any protocol used, resting myocardial thickening in the apex was higher than in the mid and apical regions, and thickening was lowest in the basal region, suggesting heterogeneous regional myocardial thickening (%) in normal subjects. Different rotation angles showed no significant change on WT, but different frame rates and tracers showed significant WT change in both sexes. Percent thickening of the myocardium was significantly higher in imaging by {sup 99m}Tc-labelled tracers than in {sup 201}Tl. Sex, radiotracers and frame rates had a significant effect on myocardial thickening, and the importance of population-specific standards should be emphasized. A normal database can serve as a standard for gated SPECT evaluation of myocardial thickening in a Japanese population and might be applicable to Asian populations having a similar physique. (orig.)

  14. Tracer-tracer relations as a tool for research on polar ozone loss

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Rolf

    2010-07-01

    The report includes the following chapters: (1) Introduction: ozone in the atmosphere, anthropogenic influence on the ozone layer, polar stratospheric ozone loss; (2) Tracer-tracer relations in the stratosphere: tracer-tracer relations as a tool in atmospheric research; impact of cosmic-ray-induced heterogeneous chemistry on polar ozone; (3) quantifying polar ozone loss from ozone-tracer relations: principles of tracer-tracer correlation techniques; reference ozone-tracer relations in the early polar vortex; impact of mixing on ozone-tracer relations in the polar vortex; impact of mesospheric intrusions on ozone-tracer relations in the stratospheric polar vortex calculation of chemical ozone loss in the arctic in March 2003 based on ILAS-II measurements; (4) epilogue.

  15. Flow Rate Measurement in Multiphase Flow Rig: Radiotracer and Conventional

    International Nuclear Information System (INIS)

    Nazrul Hizam Yusoff; Noraishah Othman; Nurliyana Abdullah; Amirul Syafiq Mohd Yunos; Rasif Mohd Zain; Roslan Yahya

    2015-01-01

    Applications of radiotracer technology are prevalent throughout oil refineries worldwide, and this industry is one of the main users and beneficiaries of the technology. Radioactive tracers have been used to a great extent in many applications i.e. flow rate measurement, RTD, plant integrity evaluation and enhancing oil production in oil fields. Chemical and petrochemical plants are generally continuously operating and technically complex where the radiotracer techniques are very competitive and largely applied for troubleshooting inspection and process analysis. Flow rate measurement is a typical application of radiotracers. For flow measurements, tracer data are important, rather than the RTD models. Research is going on in refining the existing methods for single phase flow measurement, and in developing new methods for multiphase flow without sampling. The tracer techniques for single phase flow measurements are recognized as ISO standards. This paper presents technical aspect of laboratory experiments, which have been carried out using Molybdenum-99 - Mo99 (radiotracer) to study and determine the flow rate of liquid in multiphase flow rig. The multiphase flow rig consists of 58.7 m long and 20 cm diameter pipeline that can accommodate about 0.296 m 3 of liquid. Tap water was used as liquid flow in pipeline and conventional flow meters were also installed at the flow rig. The flow rate results; radiotracer and conventional flow meter were compared. The total count method was applied for radiotracer technique and showed the comparable results with conventional flow meter. (author)

  16. Safety of adenosine stress myocardial perfusion imaging by a one-route infusion protocol

    International Nuclear Information System (INIS)

    Kawai, Yuko; Kishino, Koh

    2006-01-01

    When adenosine stress testing is performed, a vein is generally accessed in each arm. To determine whether the one-route infusion protocol, that is, infusion via one upper arm vein, is safe, myocardial perfusion imaging was performed during adenosine stress testing in patients with angina pectoris. Sixty-six consecutive patients (43 men, 68±11 years of age) with suspected coronary artery disease were enrolled in this study. For the stress test, adenosine was injected at 120 μg/kg/min for 6 minutes. Systolic blood pressure, diastolic blood pressure, and heart rate did not show any significant changes after injection of the adenosine and radioisotope (RI) tracer. Adverse events during infusion of the adenosine were seen in 42 (64%) patients and included chest discomfort/oppression in 17 (26%) and dyspnea/throat discomfort in 15 (23%). On the other hand, adverse events just after infusion of the RI tracer occurred in 5 (8%) patients and included chest oppression in 2 (3%) and dyspnea in 1 (2%). Almost all adverse events disappeared quickly without treatment. Therefore, we concluded that adenosine stress myocardial perfusion imaging using a one-route infusion protocol is safe and useful to do for patients unable to secure veins in both arms. (author)

  17. Tracking groundwater discharge to a large river using tracers and geophysics.

    Science.gov (United States)

    Harrington, Glenn A; Gardner, W Payton; Munday, Tim J

    2014-01-01

    Few studies have investigated large reaches of rivers in which multiple sources of groundwater are responsible for maintaining baseflow. This paper builds upon previous work undertaken along the Fitzroy River, one of the largest perennial river systems in north-western Australia. Synoptic regional-scale sampling of both river water and groundwater for a suite of environmental tracers ((4) He, (87) Sr/(86) Sr, (222) Rn and major ions), and subsequent modeling of tracer behavior in the river, has enabled definition and quantification of groundwater input from at least three different sources. We show unambiguous evidence of both shallow "local" groundwater, possibly recharged to alluvial aquifers beneath the adjacent floodplain during recent high-flow events, and old "regional" groundwater introduced via artesian flow from deep confined aquifers. We also invoke hyporheic exchange and either bank return flow or parafluvial flow to account for background (222) Rn activities and anomalous chloride trends along river reaches where there is no evidence of the local or regional groundwater inputs. Vertical conductivity sections acquired through an airborne electromagnetic (AEM) survey provide insights to the architecture of the aquifers associated with these sources and general groundwater quality characteristics. These data indicate fresh groundwater from about 300 m below ground preferentially discharging to the river, at locations consistent with those inferred from tracer data. The results demonstrate how sampling rivers for multiple environmental tracers of different types-including stable and radioactive isotopes, dissolved gases and major ions-can significantly improve conceptualization of groundwater-surface water interaction processes, particularly when coupled with geophysical techniques in complex hydrogeological settings. © 2013, National Ground Water Association.

  18. L-[4-11C]aspartic acid: enzymatic synthesis, myocardial uptake, and metabolism

    International Nuclear Information System (INIS)

    Barrio, J.R.; Egbert, J.E.; Henze, E.; Schelbert, H.R.; Baumgartner, F.J.

    1982-01-01

    Sterile, pyrogen-free L-[4- 11 C]aspartic acid was prepared from 11 CO 2 using phosphoenolpyruvate carboxylase and glutamic/oxaloacetic acid transaminase immobilized on Sepharose supports to determine if it is a useful indicator for in vivo, noninvasive determination of myocardial metabolism. An intracoronary bolus injection of L-[4- 11 C]aspartic acid into dog myocardium showed a triexponential clearance curve with maximal production of 11 CO 2 100 s after injection. Inactivation of myocardial transaminase activity modified the tracer clearance and inhibited the production of 11 CO 2 . Positron-computed tomography imaging showed that the 11 C activities retained in rhesus monkey myocardium are higher than those observed in dog heart after intravenous injection of L-[4- 11 C]aspartic acid. These findings demonstrated the rapid incorporation of the carbon skeleton of L-aspartic acid into the tricarboxylic acid cycle after enzymatic transamination in myocardium and suggested that L-[4- 11 C]aspartic acid could be of value for in vivo, noninvasive assessment of local myocardial metabolism

  19. Myocardial blood flow reserve is impaired in patients with aortic valve calcification and unobstructed epicardial coronary arteries.

    Science.gov (United States)

    Nel, Karen; Nam, Michael C Y; Anstey, Chris; Boos, Christopher J; Carlton, Edward; Senior, Roxy; Kaski, Juan Carlos; Khattab, Ahmed; Shamley, Delva; Byrne, Christopher D; Stanton, Tony; Greaves, Kim

    2017-12-01

    Although calcific aortic valve disease (CAVD) is associated with coronary atherosclerosis, it is not known whether early CAVD is associated with coronary microcirculatory dysfunction (CMD). We sought to investigate the relationship between myocardial blood flow reserve (MBFR) - a measure of CMD, and early CAVD in the absence of obstructive epicardial coronary artery disease. We also determined whether this relationship was independent of coronary artery disease (CAD) and hs-CRP, a marker of systemic inflammation. 183 patients with chest pain and unobstructed coronary arteries were studied. Aortic valve calcification score (AVCS), coronary total plaque length (TPL), and coronary calcium score were quantified from multislice CT. MBFR was assessed using vasodilator myocardial contrast echocardiography. Hs-CRP was measured from venous blood using a particle-enhanced immunoassay. Mean (±SD) participant age was 59.8 (9.6) years. Mean AVCS was 68 (258) AU, TPL was 15.6 (22.2) mm, and median coronary calcification score was 43.5AU. Mean MBFR was 2.20 (0.52). Mean hs-CRP was 2.52 (3.86) mg/l. Multivariable linear regression modelling incorporating demographics, coronary plaque characteristics, MBFR, and inflammatory markers, demonstrated that age (β=0.05, 95% CI: 0.02, 0.08, P=0.007), hs-CRP (β=0.09, CI: 0.02, 0.16, P=0.010) and diabetes (β=1.03, CI: 0.08, 1.98, P=0.033), were positively associated with AVCS. MBFR (β=-0.87, CI: -1.44, -0.30, P=0.003), BMI (β=-0.11, CI: -0.21, -0.01, P=0.033), and LDL (β=-0.32, CI: -0.61, -0.03, P=0.029) were negatively associated with AVCS. TPL and coronary calcium score were not independently associated with AVCS when included in the regression model. Coronary microvascular function as determined by measurement of myocardial blood flow reserve is independently associated with early CAVD. This effect is independent of the presence of coronary artery disease and also systemic inflammation. Copyright © 2017 Elsevier B.V. All rights

  20. Fundamental study on the response analysis of liquid tracer in gas-liquid, two-phase steady flow in porous media; Takoshitsu sonai kieki niso teijoryu ni okeru ekiso tracer no oto kaiseki ni kansuru kisoteki kento

    Energy Technology Data Exchange (ETDEWEB)

    Haga, D; Niibori, Y; Chida, T [Tohoku University, Sendai (Japan)

    1998-10-25

    Fluids in geothermal reservoirs are not necessarily in the single phase but is occasionally in the gas-liquid double phase. This study aims to collect fundamental knowledge about the analysis of tracer responses in a gas-liquid two-phase flow, with special attention paid to the movement of substances in the liquid-phase portion of the two-phase flow. A tracer test is conducted in a glass bead-filled layer, and then it is found that the conventional mixture-diffusion model fails to explain the outcome of the test conducted using the said very simple apparatus. The failure is attributed to the coexistence of high-saturation and low-saturation layers throughout the glass bead-filled layer, and a mathematical model is formulated, which is a development from the two-fractured-layer (TFL) model. It turns out that the mathematical model excellently describes the test result that the mixture-diffusion model fails to explain. In the numerical solution of this problem, the validity is confirmed of the use of the SIMPLEX method for the estimation of the effect of the numerical dispersion term of the third-order accurate finite upstream difference method, and of unknown parameters. 31 refs., 7 figs., 1 tab.

  1. Myocardial Perfusion: Characteristics of Distal Intramyocardial Arteriolar Trees.

    Science.gov (United States)

    Zamir, Mair; Vercnocke, Andrew J; Edwards, Phillip K; Anderson, Jill L; Jorgensen, Steven M; Ritman, Erik L

    2015-11-01

    A combination of experimental, theoretical, and imaging methodologies is used to examine the hierarchical structure and function of intramyocardial arteriolar trees in porcine hearts to provide a window onto a region of myocardial microvasculature which has been difficult to fully explore so far. A total of 66 microvascular trees from 6 isolated myocardial specimens were analyzed, with a cumulative number of 2438 arteriolar branches greater than or equal to 40 μm lumen diameter. The distribution of flow rates within each tree was derived from an assumed power law relationship for that tree between the diameter of vessel segments and flow rates that are consistent with that power law and subject to conservation of mass along hierarchical structure of the tree. The results indicate that the power law index increases at levels of arteriolar vasculature closer to the capillary level, consistent with a concomitant decrease in shear stress acting on endothelial tissue. These results resolve a long standing predicament which could not be resolved previously because of lack of data about the 3D, interconnected, arterioles. In the context of myocardial perfusion, the results indicate that the coefficient of variation of flow rate in pre-capillary distal arterioles is high, suggesting that heterogeneity of flow rate in these arterioles is not entirely random but may be due at least in part to active control.

  2. Reverse 201Tl myocardial redistribution induced by coronary artery spasm

    International Nuclear Information System (INIS)

    Xiang Dingcheng; Yin Jilin; Gong Zhihua; Xie Zhenhong; Zhang Jinhe; Wen Yanfei; Yi Shaodong

    2010-01-01

    Objective: To investigate the mechanism of reverse redistribution (RR) on dipyridamole 201 Tl myocardial perfusion studies in the patients with coronary artery spasm. Methods: Twenty-six patients with coronary artery spasm and presented as RR on dipyridamole 201 Tl myocardial perfusion studies were enlisted as RR group, while other 16 patients with no coronary artery stenosis nor RR were enlisted as control group. Dipyridamole test was repeated during coronary angiography. Corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and TIMI myocardial perfusion grade (TMPG) were measured at RR related and non-RR related coronary arteries before and after dipyridamole infusion respectively. All of the data were analyzed by Student's t-test or χ 2 -test and correlation analysis. Results: Coronary artery angiography showed slower blood flow and lower myocardial perfusion in RR related vessels when compared with non-RR related vessels in RR group, but there was no significant difference among the main coronary arteries in control group. The perfusion defects of RR area at rest were positively related to slower blood velocity at corresponding coronary arteries (r = 0.79, t =10.18, P 0.05). Conclusion: RR is related to the decreased blood flow and myocardial perfusion induced by coronary artery spasm at rest, which may be improved by stress test such as intravenous dipyridamole infusion. (authors)

  3. Site characterization and validation - Tracer migration experiment in the validation drift, report 2, part 1: performed experiments, results and evaluation

    International Nuclear Information System (INIS)

    Birgersson, L.; Widen, H.; Aagren, T.; Neretnieks, I.; Moreno, L.

    1992-01-01

    This report is the second of the two reports describing the tracer migration experiment where water and tracer flow has been monitored in a drift at the 385 m level in the Stripa experimental mine. The tracer migration experiment is one of a large number of experiments performed within the Site Characterization and Validation (SCV) project. The upper part of the 50 m long validation drift was covered with approximately 150 plastic sheets, in which the emerging water was collected. The water emerging into the lower part of the drift was collected in short boreholes, sumpholes. Sex different tracer mixtures were injected at distances between 10 and 25 m from the drift. The flowrate and tracer monitoring continued for ten months. Tracer breakthrough curves and flowrate distributions were used to study flow paths, velocities, hydraulic conductivities, dispersivities, interaction with the rock matrix and channelling effects within the rock. The present report describes the structure of the observations, the flowrate measurements and estimated hydraulic conductivities. The main part of this report addresses the interpretation of the tracer movement in fractured rock. The tracer movement as measured by the more than 150 individual tracer curves has been analysed with the traditional advection-dispersion model and a subset of the curves with the advection-dispersion-diffusion model. The tracer experiments have permitted the flow porosity, dispersion and interaction with the rock matrix to be studied. (57 refs.)

  4. Myocardial uptake of Tc-99m MDP in chronic renal failure with cardiomyopathy

    International Nuclear Information System (INIS)

    Kim, Seung Eun; Sohn, Hyung Sun; Chung, Yong An; Park, Young Ha; Kim, Sung Hoon; Chung, Soo Kyo

    2000-01-01

    A uremic patient on hemodialysis, who had concurrent cardiomyopathy showed intense myocardial uptake of 99m Tc-methylene diphosphonate (MDP). The presumed cause of uptake in the myocardium is metastatic calcification due to hypercalcemia secondary to the renal failure. However, supplementary mechanism caused by cardiomyopathy should be considered. We describe a case with bone tracer uptake in the myocardium in the absence of infarction in a patient with chronic renal failure.=20

  5. TOWARD THE QUESTION OF ISCHEMIC MYOCARDIAL DYSFUNCTION

    Directory of Open Access Journals (Sweden)

    V. V. Kalyuzhin

    2014-01-01

    Full Text Available The authors of the review have analyzed papers published on the problem of ischemic myocardial dysfunction. They begin with a definition of the term “ischemia” (derived from two Greek words: ischō, meaning to hold back, and haima, meaning blood - a condition at which the arterial blood flow is insufficient to provide enough oxygen to prevent intracellular respiration from shifting from the aerobic to the anaerobic form. The poor rate of ATP generation from this process causes a decrease in cellular ATP, a concomitant rise in ADP, and ultimately, to depression inotropic (systolic and lusitropic (diastolic function of the affected segments of the myocardium. But with such simplicity of basic concepts, the consequences of ischemia so diverse. Influence of an ischemia on myocardial function so unequally at different patients, which is almost impossible to find two identical cases (as in the case of fingerprints. It depends on the infinite variety of lesions of coronary arteries, reperfusion (time and completeness of restoration of blood flow and reactions of a myocardium which, apparently, has considerable flexibility in its response. Ischemic myocardial dysfunction includes a number of discrete states, such as acute left ventricular failure in angina, acute myocardial infarction, ischemic cardiomyopathy, stunning, hibernation, pre- and postconditioning. There are widely differing underlying pathophysiologic states. The possibility exists that several of these states can coexist.

  6. Comparison of quantitative myocardial perfusion imaging CT to fluorescent microsphere-based flow from high-resolution cryo-images

    Science.gov (United States)

    Eck, Brendan L.; Fahmi, Rachid; Levi, Jacob; Fares, Anas; Wu, Hao; Li, Yuemeng; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) has the potential to provide quantitative measures of myocardial blood flow (MBF) which can aid the diagnosis of coronary artery disease. We evaluated the quantitative accuracy of MPI-CT in a porcine model of balloon-induced LAD coronary artery ischemia guided by fractional flow reserve (FFR). We quantified MBF at baseline (FFR=1.0) and under moderate ischemia (FFR=0.7) using MPI-CT and compared to fluorescent microsphere-based MBF from high-resolution cryo-images. Dynamic, contrast-enhanced CT images were obtained using a spectral detector CT (Philips Healthcare). Projection-based mono-energetic images were reconstructed and processed to obtain MBF. Three MBF quantification approaches were evaluated: singular value decomposition (SVD) with fixed Tikhonov regularization (ThSVD), SVD with regularization determined by the L-Curve criterion (LSVD), and Johnson-Wilson parameter estimation (JW). The three approaches over-estimated MBF compared to cryo-images. JW produced the most accurate MBF, with average error 33.3+/-19.2mL/min/100g, whereas LSVD and ThSVD had greater over-estimation, 59.5+/-28.3mL/min/100g and 78.3+/-25.6 mL/min/100g, respectively. Relative blood flow as assessed by a flow ratio of LAD-to-remote myocardium was strongly correlated between JW and cryo-imaging, with R2=0.97, compared to R2=0.88 and 0.78 for LSVD and ThSVD, respectively. We assessed tissue impulse response functions (IRFs) from each approach for sources of error. While JW was constrained to physiologic solutions, both LSVD and ThSVD produced IRFs with non-physiologic properties due to noise. The L-curve provided noise-adaptive regularization but did not eliminate non-physiologic IRF properties or optimize for MBF accuracy. These findings suggest that model-based MPI-CT approaches may be more appropriate for quantitative MBF estimation and that cryo-imaging can support the development of MPI-CT by providing spatial distributions of MBF.

  7. Myocardial perfusion in silent myocardial ischemia

    International Nuclear Information System (INIS)

    Narita, Michihiro; Kurihara, Tadashi; Murano, Kenichi; Usami, Masahisa

    1989-01-01

    To investigate myocardial perfusion in silent myocardial ischemia, we performed exercise stress myocardial tomography with thallium-201 (Tl) in 85 patients with coronary artery disease (CAD). Exercise stress myocardial tomography was obtained both immediately after exercise and three hours later. Patients were classified into two groups according to the presence (Symptomatic Group, n=36) or absence (Silent Group, n=49) of chest pain during exercise stress. Clinical features (age, gender and history of myocardial infarction) and arteriographically determined severity of CAD were the same in both groups. The extent of myocardial ischemia (% Ischemia) estimated by exercise stress myocardial tomography was the same in each group (30±10 % in Silent Group, 28±12 % in Symptomatic Group, NS). The severity of exercise-induced myocardial ischemia was expressed as a minimal value of myocardial Tl washout rate (minimal WOR) of each patient. Although exercise heart rate was identical in both groups, minimal WOR in Silent Group was significantly higher than that of Symptomatic Group (4±10% vs -16±14%, p<0.001). The study in patients who exhibited both silent and symptomatic ischemia showed the same results. These findings suggest that the severity of ischemia is a fundamental factor in determining the presence or absence of pain during exercise induced ischemia. (author)

  8. Regional myocardial perfusion of cardioplegic solutions

    International Nuclear Information System (INIS)

    Eugene, J.; Lyons, K.P.; Ott, R.A.; Gelezunas, V.L.; Chang, C.W.; Kowall, M.G.; Haiduc, N.J.

    1987-01-01

    We compared the regional myocardial perfusion of blood cardioplegic solution (BCP) and crystalloid cardioplegic solution (CCP) in 14 mongrel dogs. Cardiopulmonary bypass was established at 28 degrees C, and a hydraulic occluder was placed around the proximal left anterior descending (LAD) coronary artery. In group 1 (N = 7) collateral coronary arteries were ligated; in group 2 (N = 7) collateral coronary arteries were left in situ. After the aorta was clamped, BCP and CCP were alternately perfused at 200 ml/min. The occluder was inflated to produce moderate, severe, and critical LAD stenosis, and regional perfusion was measured by xenon-133 washout with the Silicon Avalanche Radiation Detector. BCP infusion produced a consistently higher aortic pressure, but CCP flow was better than BCP flow under all conditions, particularly without coronary collaterals. Regional myocardial perfusion of CCP is superior to BCP

  9. Assessment of a Geothermal Doublet in the Malm Aquifer Using a Push-Pull Tracer Test

    Science.gov (United States)

    Lafogler, Mark; Somogyi, Gabriella; Nießner, Reinhard; Baumann, Thomas

    2013-04-01

    Geothermal exploration of the Malm aquifer in Bavaria is highly successful. Data about the long-term operation, however, is still scarce, although detailed knowledge about the processes occurring in the aquifer is a key requirement to run geothermal facilities efficiently and economically. While there usually is a constant flow of data from the production well (temperatures, hydraulic data, hydrochemical conditions, gas composition) not even the temperatures in the immediate surrounding of the reinjection well are accessible or known. In 2011 the geothermal facility in Pullach was extended with a third geothermal well reaching into the Malm aquifer which is now used as a reinjection well. The former reinjection well was converted to a production well after 5 years of operation. This setting offers a unique opportunity to study the processes in the vicinity of a reinjection well and provides the data base to describe the hydraulic, thermal and hydrochemical performance of the reservoir. The viscosity of the reinjected cold water is increasing by 60% compared to the production well, thus one would expect an increase of the reinjection pressure as the cold water plume spreads around the reinjection well. Measurements, however, show a significant decrease of the reinjection pressure, suggesting processes in the aquifer which positively change the hydraulic properties and overcompensate the viscosity effects. Hydrochemical data and modeling indicate that a dissolution of the matrix along the flow pathways is responsible for the decreasing reinjection pressures. The change of the flow direction from reinjection to production was used to conduct a push-pull tracer test. Here, a series of fluorescent dye pulses was added to the reinjected water before the former reinjection well was shut down (push phase). These tracers included a conservative tracer (Fluorescein), surface-sensitive tracers (Eosin/Sulforhodamin B), and a NAPL-sensitive tracer (Na-Naphthionate). After

  10. Test-retest repeatability of myocardial blood flow and infarct size using 11C-acetate micro-PET imaging in mice

    International Nuclear Information System (INIS)

    Croteau, Etienne; Renaud, Jennifer M.; McDonald, Matthew; Klein, Ran; DaSilva, Jean N.; Beanlands, Rob S.B.; DeKemp, Robert A.

    2015-01-01

    Global and regional responses of absolute myocardial blood flow index (iMBF) are used as surrogate markers to assess response to therapies in coronary artery disease. In this study, we assessed the test-retest repeatability of iMBF imaging, and the accuracy of infarct sizing in mice using 11 C-acetate PET. 11 C-Acetate cardiac PET images were acquired in healthy controls, endothelial nitric oxide synthase (eNOS) knockout transgenic mice, and mice after myocardial infarction (MI) to estimate global and regional iMBF, and myocardial infarct size compared to 18 F-FDG PET and ex-vivo histology results. Global test-retest iMBF values had good coefficients of repeatability (CR) in healthy mice, eNOS knockout mice and normally perfused regions in MI mice (CR = 1.6, 2.0 and 1.5 mL/min/g, respectively). Infarct size measured on 11 C-acetate iMBF images was also repeatable (CR = 17 %) and showed a good correlation with the infarct sizes found on 18 F-FDG PET and histopathology (r 2 > 0.77; p < 0.05). 11 C-Acetate micro-PET assessment of iMBF and infarct size is repeatable and suitable for serial investigation of coronary artery disease progression and therapy. (orig.)

  11. Effect of nicorandil on the myocardial tissue perfusion and myocardial cell injury in patients with diabetes after PCI

    Directory of Open Access Journals (Sweden)

    Xue-Li Ren1

    2017-04-01

    Full Text Available Objective: To study the effect of nicorandil on the myocardial tissue perfusion and myocardial cell damage in patients with diabetes after percutaneous coronary intervention (PCI. Methods: 68 patients with coronary heart disease and type 2 diabetes mellitus who received PCI in our hospital between May 2011 and September 2015 were collected and then divided into observation group and control group (n=34 according to the single-blind randomized control method. Control group of patients received PCI alone, and the observation group of patients received nicorandil therapy after PCI. After treatment, real-time myocardial ultrasound contrast was used to evaluate the myocardial perfusion of two groups of patients; blood biochemical analyzer was used to detect the contents of peripheral blood myocardial enzyme spectrum indexes; the ELISA method was used to detect the contents of serum oxidative stress indicators; RIA method was used to detect the contents of serum apoptosis molecules. Results: After treatment, the myocardial tissue perfusion parameters plateau peak intensity (A, slope rate of curve (β and myocardial blood flow (A×β levels of observation group were significantly higher than those of control group (P<0.05; peripheral blood myocardial enzyme spectrum indexes creatine kinase (CK, lactate dehydrogenase (LDH, troponin I (cTnI and glutamic oxalacetic transaminase (GOT contents of observation group were significantly lower than those of control group (P<0.05; serum vitamin E (VitE and vitamin C (VitC contents of observation group were significantly higher than those of control group while malondialdehyde (MDA, advanced oxidation protein products (AOPPs, soluble apoptosis-associated factor (sFas and soluble apoptosis-associated factor ligand (sFasL contents were lower than those of control group (P<0.05. Conclusion: Adjuvant nicorandil therapy can improve the myocardial perfusion and reduce the myocardial cell injury in patients with coronary

  12. Groundwater Recharge and Flow Regime revealed by multi-tracers approach in a headwater, North China Plain

    Science.gov (United States)

    Sakakibara, Koichi; Tsujimura, Maki; Song, Xianfang; Zhang, Jie

    2014-05-01

    Groundwater recharge is a crucial hydrological process for effective water management especially in arid/ semi-arid regions. However, the insufficient number of specific research regarding groundwater recharge process has been reported previously. Intensive field surveys were conducted during rainy season, mid dry season, and end of dry season, in order to clarify comprehensive groundwater recharge and flow regime of Wangkuai watershed in a headwater, which is a main recharge zone of North China Plain. The groundwater, spring, stream water and lake water were sampled, and inorganic solute constituents and stable isotopes of oxygen 18 and deuterium were determined on all water samples. Also the stream flow rate was observed. The solute ion concentrations and stable isotopic compositions show that the most water of this region can be characterized by Ca-HCO3 type and the main water source is precipitation which is affected by altitude effect of stable isotopes. In addition, the river and reservoir of the area seem to recharge the groundwater during rainy season, whereas interaction between surface water and groundwater does not become dominant gradually after the rainy season. The inversion analysis applied in Wangkuai watershed using simple mixing model represents an existing multi-flow systems which shows a distinctive tracer signal and flow rate. In summary, the groundwater recharged at different locations in the upper stream of Wangkuai reservoir flows downward to alluvial fan with a certain amount of mixing together, also the surface water recharges certainly the groundwater in alluvial plain in the rainy season.

  13. New noninvasive diagnosis of myocardial ischemia of the left circumflex coronary artery using coronary flow reserve measurement by transthoracic Doppler echocardiography. Comparison with thallium-201 single photon emission computed tomography

    International Nuclear Information System (INIS)

    Fujimoto, Kohei; Watanabe, Hiroyuki; Hozumi, Takeshi; Otsuka, Ryo; Hirata, Kumiko; Yamagishi, Hiroyuki; Yoshiyama, Minoru; Yoshikawa, Junichi

    2004-01-01

    The usefulness of coronary flow reserve measurement in the left circumflex coronary artery by transthoracic Doppler echocardiography to detect myocardial ischemia was compared with exercise thallium-201 single photon emission computed tomography (SPECT). Transthoracic Doppler echocardiography was performed in 110 patients with suspected coronary artery disease. Color Doppler signals of the left circumflex coronary artery flow in the apical four-chamber view were identified, and the velocities at rest and during hyperemia recorded for calculation of coronary flow reserve by the pulsed Doppler method. All patients underwent SPECT within 1 week of the transthoracic Doppler echocardiographic study. Coronary flow reserve in the left circumflex coronary artery was measured in 79 (72%) of 110 patients. SPECT revealed reversible perfusion defect in the left circumflex coronary artery territories in 12 of 69 patients excluding those with multivessel disease. Coronary flow reserve <2.0 had a sensitivity of 92% and specificity of 96% for reversible perfusion defect detected by SPECT. Noninvasive coronary flow reserve measurement in the left circumflex coronary artery by transthoracic Doppler echocardiography can estimate myocardial ischemia in the left ventricular lateral regions. (author)

  14. Evaluation of TRUE-1 tests with sorbing tracers using CHAN3D

    International Nuclear Information System (INIS)

    Moreno, L.

    2001-01-01

    Three tracer tests (STT1a, STT1b and STT2) with sorbing species performed as a part of the TRUE-1 experiments are studied. The tests were carried out in a radially converging flow geometry with a travel distance of about 5 m The injected sorbing tracers were: Na + , Sr 2+ , Ca 2+ , Ba 2+ , Cs + , Co 2+ , Rb + . The sorption properties of the tracer cover a wide interval. The tracer tests were modelled using the Channel Network Model, which assumes that fluid flow and solute transport take place through a network of channels. It includes solute transport by advection, diffusion into the rock matrix, and sorption within the matrix and onto the channel surface. Sorption and diffusion data were obtained from laboratory measurements carried out over generic Aespoe material. Some measurements were made using material from the Feature A. Large differences are found between the experimental and the predicted breakthrough curves. The predicted times are much shorter than the experimental ones. An attempt is made to explain these differences using various possible retardation mechanisms. Finally, it is concluded that several mechanisms must act simultaneously in order to explain the large differences

  15. Proceedings of Tracer 3. International Conference on Tracers and Tracing Methods

    International Nuclear Information System (INIS)

    2004-01-01

    Tracer 3 conference is a continuation of former Tracer 1 (1998) and Tracer 2 (2001) conferences organized by CNRS - Nancy France. The objective of this 3rd conference is presentation of different aspects of tracer method applications and development of tracer methodology.The new field of activity presented at the Conference was application of stable isotopes as natural tracers for investigations of environmental processes. The conference gave the possibility for scientific information exchange between specialists from different fields of activity such as chemical engineering, chemistry, bioengineering, environmental engineering, hydrology, civil engineering, metallurgy, etc. The presentations were divided into groups covering the principal items of Conference. Section A. Fundamental development - RTD and tracer methodology, - RTD methodology and Computational Fluid Dynamics (CFD), - New tracers and detectors. Section B. Industrial applications - Environment, - Geology, hydrogeology and oil field applications, - Civil engineering, mineral engineering and metallurgy applications, - Food engineering and bioengineering, - Material engineering, - Chemical engineering. During the Conference INIS promotion materials were exposed by INIS liaison officer for Poland

  16. Proceedings of Tracer 3. International Conference on Tracers and Tracing Methods

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    Tracer 3 conference is a continuation of former Tracer 1 (1998) and Tracer 2 (2001) conferences organized by CNRS - Nancy France. The objective of this 3rd conference is presentation of different aspects of tracer method applications and development of tracer methodology.The new field of activity presented at the Conference was application of stable isotopes as natural tracers for investigations of environmental processes. The conference gave the possibility for scientific information exchange between specialists from different fields of activity such as chemical engineering, chemistry, bioengineering, environmental engineering, hydrology, civil engineering, metallurgy, etc. The presentations were divided into groups covering the principal items of Conference. Section A. Fundamental development - RTD and tracer methodology, - RTD methodology and Computational Fluid Dynamics (CFD), - New tracers and detectors. Section B. Industrial applications - Environment, - Geology, hydrogeology and oil field applications, - Civil engineering, mineral engineering and metallurgy applications, - Food engineering and bioengineering, - Material engineering, - Chemical engineering. During the Conference INIS promotion materials were exposed by INIS liaison officer for Poland.

  17. Radioisotope tracer instrument and its application to the detection of the groundwater parameters

    International Nuclear Information System (INIS)

    Chen Jiansheng

    1988-01-01

    The application of radioisotope tracer technique and probe can result in the detection of groundwater flow direction, flow velocity and vertical currents in one single well. The tracer probe consists of the source injector and the components related with direction detection, location and velocity measurement. The nuclear detector employs a thermoluminescence detector (TLD) and a direct reading ionization chamber (IC) for the detection of flow direction and also employs a new method of photofluorography location for the determination of the probe's northern or southern position in the well, thereby greatly simplifying the design of the direction-detecting probe. The velocity measuring section includes ground receiving instruments and meters for conducting point or whole-borehole measurement. It is also possible to carry out interconnection tests and dispersion tests. With the applications to the ascertaining of the groundwater distribution in the karst region as well as the execution of the dispersion tests related with environmental protection and so on, it has been confirmed that the radioisotope tracer instrument has a broad scope of application and practicability. (author). 5 refs, 6 figs

  18. Using Temperature as a Tracer to Study Fluid Flow Patterns On and Offshore Taiwan

    Science.gov (United States)

    Chi, W. C.

    2017-12-01

    Fluid flows are a dynamic system in the crust that affect crustal deformation and formation of natural resources. It is difficult to study fluid flow velocity instrumentally, but temperature data offers a quantitative tool that can be used as a tracer to study crustal hydrogeology. Here we present numerical techniques we have applied to study the fluid migration velocity along conduits including faults in on and offshore settings. Offshore SW Taiwan, we use a bottom-simulating reflector (BSR) from seismic profiles to study the temperature field at several hundred meters subbottom depth. The BSR is interpreted as the base of a gas hydrate stability zone under the seabed. Gas hydrates are solid-state water with gas molecules enclosed, which can be found where the temperature, pressure, and salinity conditions allow hydrates to be stable. Using phase diagrams and hydro pressure information we can derive the temperature at the BSR. BSRs are widespread in the study area, providing very dense temperature field information which shows upward bending of the BSR near faults. We have quantitatively estimated the 1D and 2D fluid flow patterns required to fit the BSR-based temperature field. This shows that fault zones can act as conduits with high permeability parallel to the fault planes. On the other hand, fault zones can also act as barriers to fluid flow, as demonstrated in our onland temperature data. We have collected temperature profiles at several bore holes onland that are very close together. The preliminary results show that the fault zones separate the ground water systems, causing very different geothermal gradients. Our results show that the physical properties of fault zones can be anisotropic, as demonstrated in previous work. Future work includes estimating the regional water expulsion budget offshore SW Taiwan, in particular for several gas hydrate sites.

  19. A new approach to tracer transport analysis: From fracture systems to strongly heterogeneous porous media

    International Nuclear Information System (INIS)

    Tsang, Chin-Fu.

    1989-02-01

    Many current development and utilization of groundwater resources include a study of their flow and transport properties. These properties are needed in evaluating possible changes in groundwater quality and potential transport of hazardous solutes through the groundwater system. Investigation of transport properties of fractured rocks is an active area of research. Most of the current approaches to the study of flow and transport in fractured rocks cannot be easily used for analysis of tracer transport field data. A new approach is proposed based on a detailed study of transport through a fracture of variable aperture. This is a two-dimensional strongly heterogeneous permeable system. It is suggested that tracer breakthrough curves can be analyzed based on an aperture or permeability probability distribution function that characterizes the tracer flow through the fracture. The results are extended to a multi-fracture system and can be equally applied to a strongly heterogeneous porous medium. Finally, the need for multi-point or line and areal tracer injection and observation tests is indicated as a way to avoid the sensitive dependence of point measurements on local permeability variability. 30 refs., 15 figs

  20. Tracers Reveal Recharge Elevations, Groundwater Flow Paths and Travel Times on Mount Shasta, California

    Directory of Open Access Journals (Sweden)

    Elizabeth Peters

    2018-01-01

    Full Text Available Mount Shasta (4322 m is famous for its spring water. Water for municipal, domestic and industrial use is obtained from local springs and wells, fed by annual snow melt and sustained perennially by the groundwater flow system. We examined geochemical and isotopic tracers in samples from wells and springs on Mount Shasta, at the headwaters of the Sacramento River, in order to better understand the hydrologic system. The topographic relief in the study area imparts robust signatures of recharge elevation to both stable isotopes of the water molecule (δ18O and δD and to dissolved noble gases, offering tools to identify recharge areas and delineate groundwater flow paths. Recharge elevations determined using stable isotopes and noble gas recharge temperatures are in close agreement and indicate that most snowmelt infiltrates at elevations between 2000 m and 2900 m, which coincides with areas of thin soils and barren land cover. Large springs in Mt Shasta City discharge at an elevation more than 1600 m lower. High elevation springs (>2000 m yield very young water (<2 years while lower elevation wells (1000–1500 m produce water with a residence time ranging from 6 years to over 60 years, based on observed tritium activities. Upslope movement of the tree line in the identified recharge elevation range due to a warming climate is likely to decrease infiltration and recharge, which will decrease spring discharge and production at wells, albeit with a time lag dependent upon the length of groundwater flow paths.

  1. CityFlux perfluorocarbon tracer experiments

    Science.gov (United States)

    Petersson, F. K.; Martin, D.; White, I. R.; Henshaw, S. J.; Nickless, G.; Longley, I.; Percival, C. J.; Gallagher, M.; Shallcross, D. E.

    2010-07-01

    In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m. The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site. Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail. The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this. The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

  2. Tracer theory

    International Nuclear Information System (INIS)

    Margrita, R.

    1988-09-01

    Tracers are used in many fields of science to investigate mass transfer. The scope of tracers applications in Service of Applications Radioisotopes (S.A.R.-France) is large and concerns natural and industrial systems such as Sciences of earth: hydrology - civil engineering - Sedimentology - environmental studies. Industrial field: chemical engineering - mechanical engineering. A general tracer methodology has been developed in our laboratories from these different applications fields and this paper shows these different points of view in using tracers; our wish is that the methods used in an experimental field can be employed in an another one

  3. Site characterization and validation - monitoring of saline tracer transport by borehole radar measurements

    International Nuclear Information System (INIS)

    Olsson, O.; Andersson, P.; Gustafsson, E.

    1991-08-01

    The objective of this experiment was to map tracer transport in fractured crystalline rock through a combination of radar difference tomography and measurements of tracer concentration in boreholes and the validation drift. The experiment was performed twice, first the D-boreholes were used as a sink and then they were replaced by the validation drift and the experiment repeated. In both experiments saline tracer (200 ml/min, 2% salinity) was injected into fracture zone H about 25 m from the validation drift. The experiment revealed an inhomogeneous transmissivity distribution in Zone H. A significant portion of the tracer is transported upwards along Zone H and towards boreholes T1, T2, and W1. The breakthrough data from both experiments indicate that there are two major transport paths from borehole C2 to the D-boreholes/validation drift. One slow and diluted path to the bottom of the drift which carries the bulk of the mass and one fast path to the crown of the drift with high tracer concentration. The radar difference tomograms show that some tracer is lost through Zone S which intersects Zone H and is nearly perpendicular to it. The intersection between the two zones seems to constitute a preferred flow path. The breakthrough data and the radar difference tomograms have also been used to estimate flow porosity. The estimate obtained area of the same order approximately 10 -4 . (au) (28 refs.)

  4. Leak detection and localization in natural and artificial dams using tracer techniques

    International Nuclear Information System (INIS)

    Molinari, J.

    1975-01-01

    Leak detection and localization procedures using often-unknown techniques of identification by natural or artificial tracers are reported. From the analysis of data supplied by natural tracers, or by artificial tracer methods which involve the direct observation of warning phenomena, it is possible to estimate the extent of the infiltrations, define their origin and under certain circumstances determine the main hydrodynamic flow parameters so that their development may be followed. The examples of application and interpretation were taken from the numerous studies carried out in this field by the CEA, where many original investigation methods have been employed [fr

  5. Environmental tracers as indicators of groundwater flow and evolution in a fractured rock aquifer, Clare Valley, South Australia

    International Nuclear Information System (INIS)

    Love, A.J.; Cook, P.G.; Herczeg, A.L.; Simmons, C.T.

    1999-01-01

    Environmental tracers, chemistry and hydraulic data have been used to develop a conceptual model for groundwater flow in a fractured rock aquifer, at Clare, South Australia. In the upper 36 m there is relatively high horizontal flow, closely spaced fractures and large apertures. Below 36 m, horizontal flow rates are less and apertures become smaller. A sub horizontal fracture at 36 m separates the upper system from flow systems below. There is minimum vertical connection of groundwater above and below 36 m as indicated by low hydraulic conductivity and a steep 14 C concentration gradient. The observed linear trends in chemistry and isotope data are a result of mixing between old saline water and relatively younger fresh water. Greater mixing has occurred in the upper 36 m, with the amount of mixing diminishing with depth. We propose that this mixing is a recent process that has been triggered as a result of increased recharge to the system since the clearing of native vegetation approximately 100 years ago. Increased recharge of lower salinity water has resulted in the establishment of concentration gradients between the matrix and the fractures. This has resulted in diffusion of relatively immobile water in the matrix into relatively fast moving water in the fractures. Greater flushing has occurred in the upper 36 m due greater fracture density and larger apertures and higher horizontal flow rates. (author)

  6. Regional myocardial metabolism in patients with acute myocardial infarction assessed by positron emission tomography

    International Nuclear Information System (INIS)

    Schwaiger, M.; Brunken, R.; Grover-McKay, M.; Krivokapich, J.; Child, J.; Tillisch, J.H.; Phelps, M.E.; Schelbert, H.R.

    1986-01-01

    Positron emission tomography has been shown to distinguish between reversible and irreversible ischemic tissue injury. Using this technique, 13 patients with acute myocardial infarction were studied within 72 hours of onset of symptoms to evaluate regional blood flow and glucose metabolism with nitrogen (N)-13 ammonia and fluorine (F)-18 deoxyglucose, respectively. Serial noninvasive assessment of wall motion was performed to determine the prognostic value of metabolic indexes for functional tissue recovery. Segmental blood flow and glucose utilization were evaluated using a circumferential profile technique and compared with previously established semiquantitative criteria. Relative N-13 ammonia uptake was depressed in 32 left ventricular segments. Sixteen segments demonstrated a concordant decrease in flow and glucose metabolism. Regional function did not change over time in these segments. In contrast, 16 other segments with reduced blood flow revealed maintained F-18 deoxyglucose uptake consistent with remaining viable tissue. The average wall motion score improved significantly in these segments (p less than 0.01), yet the degree of recovery varied considerably among patients. Coronary anatomy was defined in 9 of 13 patients: patent infarct vessels supplied 8 of 10 segments with F-18 deoxyglucose uptake, while 10 of 13 segments in the territory of an occluded vessel showed concordant decreases in flow and metabolism (p less than 0.01). Thus, positron emission tomography reveals a high incidence of residual tissue viability in ventricular segments with reduced flow and impaired function during the subacute phase of myocardial infarction. Absence of residual tissue metabolism is associated with irreversible injury, while preservation of metabolic activity identifies segments with a variable outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Thallium-201 myocardial imaging for evaluation of right-ventricular overloading

    International Nuclear Information System (INIS)

    Kondo, M.; Kubo, A.; Yamazaki, H.; Ohsuzu, F.; Handa, S.; Tsugu, T.; Masaki, H.; Kinoshita, F.; Hashimoto, S.

    1978-01-01

    This study evaluated the specificity and sensitivity of Tl-201 myocardial imaging in the detection of right-ventricular (RV) overloading. Right-ventricular visualization (RVV) after administration of Tl-201 chloride was studied on 99 patients with various heart diseases. Tracer uptake in the free wall of the RV was graded in four degrees. The degree of RVV was compared with the findings of cardiac catheterization. The comparisons indicated that the uptake increased in step with the inreases in RV systolic pressure, RV end-diastolic pressure, mean pulmonary arterial pressure, total pulmonary vascular resistance, and stroke-work index of the right ventricle (P < 0.05--P < 0.001). Of the patients with visible RV, all but three had RV overloading, and all but three of those without RVV had normal RV systolic pressure. Myocardial images also reflect the type of RV overloading. In patients with RV pressure overloading, the septum showed a tendency to appear straight. In patients with atrial septal defect leading to RV volume overloading, the RV cavity was dilated, the LV image small, and the septum convex toward the RV cavity. These results indicate that Tl-201 myocardial imaging is a sensitive and specific method for the study of RV overloading

  8. Instantaneous axial velocity of a radioactive tracer determined with radioactive particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Fraguio, Maria Sol; Cassanello, Miryan C., E-mail: miryan@di.fcen.uba.a [Universidad de Buenos Aires (Argentina). Facultad de Ciencias Exactas y Naturales. Programa de Investigacion y Desarrollo de Fuentes Alternativas de Materias Primas y Energia (PINMATE); Cardona, Maria Angelica; Hojman, Daniel, E-mail: cardona@tandar.cnea.gov.a [CONICET, Buenos Aires (Argentina); Somacal, Hector [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina). Centro Atomico Constituyentes. Dept. de Fisica

    2009-07-01

    Radioactive Particle Tracking (RPT) is a technique that has been successfully used to get features of the liquid and/or the solid motion in multiphase contactors. It is one of the rare techniques able to provide experimental data in dense and strongly turbulent multiphase media. Validation of the technique has always been based on comparing the estimated mean velocity to an imposed mean velocity although the extracted features are frequently related to the instantaneous velocities. The present work pursues the analysis, through calibration experiments, of the ability of RPT to get the actual tracer instantaneous velocities. With this purpose, the motion of a radioactive tracer attached to a moving rod driven by a pneumatic system is reconstructed from the combined response of an array of 10 NaI(Tl) scintillation detectors. Simultaneously, the tracer motion is registered through an encoder able to establish the axial tracer coordinate with high precision and high time resolution. The tracer is a gold particle, activated by neutron bombardment. The rod is moved at different velocities and it travels upwards and downwards close to the column centre. A mini-pilot scale bubble column is used as the test facility. The model liquid is tap water in batch mode and the gas is air, flowing at different gas velocities, spanning the homogeneous and the heterogeneous flow regimes. Time series of the entirety response of all the detectors, while the rod is moving at different imposed velocities within the two phase emulsion, are measured with a sampling period of 0.03 s during about 2 minutes. The instantaneous tracer positions and velocities reconstructed from RPT and the one obtained from the encoder response are compared under different operating conditions and for different tracer velocities. (author)

  9. Myocardial fatty acid utilisation during exercise induced ischemia in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Virtanen, K.S.; Nikkinen, P.; Lindroth, L.; Kuikka, J.T.

    2002-01-01

    Aim: Reversible or irreversible myocardial damage due to ischemia correlates with altered membrane functions of the cells. To compare myocardial free fatty acid (FFA) metabolism and flow during exercise induced ischemia we studied ten patients with coronary artery disease but without previous myocardial infarction. Methods: A series of post-exercise single-photon emission computed tomography (SPECT) measurements was performed after injection of 123 I labelled heptadecanoic acid (HDA). Myocardial perfusion was estimated from the separately performed exercise-redistribution thallium study. Fatty acid metabolic rate, thallium uptake and washout were calculated for anterior, lateral, posterior and septal segments. Results: The more reduced post-exercise FFA metabolic rate (-63±18%, mean ±1 SD) compared to flow (-36±16%) was related to the severity of myocardial ischemia and wall motion abnormalities. Conclusion: In this small group of patients, the reduced post-exercise FFA metabolic rate tentatively suggests a parsimonious workload of the exercising myocardium by reducing oxygen consumption in patients with coronary artery disease. (orig.) [de

  10. Assessment of maximal myocardial perfusion by ECG-triggered digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Pijls, N.H.J.; Uijen, G.J.H.; Werf, T. van der (Katholieke Univ. Nijmegen (Netherlands). Cardiology Dept.)

    1991-01-01

    Early studies about calculation of coronary blood flow by analysis of contrast agent passage on the coronary arteriogram were reported more than 2 decades ago by Rutishauser et al. and Smith et al. Thereafter is was shown that visualization of contrast passage through the myocardium could be enhanced by ECG-triggered digital subtraction imaging and it was suggested that myocardial flow could be calculated by studying the temporal changes in contrast intensity in a myocardial region of interest (ROI) as a function of time: the time density curve (TDC). (orig./GDG).

  11. Regional myocardial extraction of a radioiodinated branched chain fatty acid during right ventricular pressure overload due to acute pulmonary hypertension

    International Nuclear Information System (INIS)

    Hurford, W.; Lowenstein, E.; Zapol, W.; Barlai-Kovach, M.; Livni, E.; Elmaleh, D.R.; Strauss, H.W.

    1985-01-01

    To determine whether branched chain fatty acid extraction is reduced during right ventricular (RV) dysfunction due to acute pulmonary artery hypertension, studies were done in 6 anesthetized dogs. Regional branched chain fatty acid extraction was measured by comparing the myocardial uptake of I-125 labeled 15-[p-(iodophenyl)]-3-methylpentadecanoic acid (I-PDA) to myocardial blood flow. Acute pulmonary hypertension was induced by incremental intravenous injection of 100 micron diameter glass beads into six pentobarbital anesthetized, mechanically ventilated dogs. Myocardial blood flow was measured by radiolabeled microspheres both under baseline conditions and during pulmonary hypertension. Mean RV pressure rose from 12 +- 2 (mean +- SEM) to 30 +-3mmHg resulting in a 225 +- 16% increase in RV stroke work. RV ejection fraction, as assessed by gated blood pool scans fell from 39 +- 2 to 18 +- 2%. Left ventricular (LV) pressures, stroke work and ejection fraction were unchanged. Myocardial blood flow increased 132 + 59% in the RV free wall and 67 +- 22% in the RV septum. LV blood flow was unchanged. Despite increased RV work and myocardial blood flow, no differences were noted in the branched chain fatty acid extraction ratios among LV or RV free walls or septum. The authors conclude that early RV dysfunction associated with pulmonary artery hypertension is not due to inadequate myocardial blood flow or branched chain fatty acid extraction

  12. Comparison of clinical tools for measurements of regional stress and rest myocardial blood flow assessed with 13N-ammonia PET/CT.

    Science.gov (United States)

    Slomka, Piotr J; Alexanderson, Erick; Jácome, Rodrigo; Jiménez, Moises; Romero, Edgar; Meave, Aloha; Le Meunier, Ludovic; Dalhbom, Magnus; Berman, Daniel S; Germano, Guido; Schelbert, Heinrich

    2012-02-01

    Several models for the quantitative analysis of myocardial blood flow (MBF) at stress and rest and myocardial flow reserve (MFR) with (13)N-ammonia myocardial perfusion PET have been implemented for clinical use. We aimed to compare quantitative results obtained from 3 software tools (QPET, syngo MBF, and PMOD), which perform PET MBF quantification with either a 2-compartment model (QPET and syngo MBF) or a 1-compartment model (PMOD). We considered 33 adenosine stress and rest (13)N-ammonia studies (22 men and 11 women). Average age was 54.5 ± 15 y, and average body mass index was 26 ± 4.2. Eighteen patients had a very low likelihood of disease, with no chest pain, normal relative perfusion results, and normal function. All data were obtained on a PET/CT scanner in list mode with CT attenuation maps. Sixteen dynamic frames were reconstructed (twelve 10-s, two 30-s, one 1-min, and one 6-min frames). Global and regional stress and rest MBF and MFR values were obtained with each tool. Left ventricular contours and input function region were obtained automatically in system QPET and syngo MBF and manually in PMOD. The flow values and MFR values were highly correlated among the 3 packages (R(2) ranging from 0.88 to 0.92 for global values and from 0.78 to 0.94 for regional values. Mean reference MFR values were similar for QPET, syngo MBF, and PMOD (3.39 ± 1.22, 3.41 ± 0.76, and 3.66 ± 1.19, respectively) by 1-way ANOVA (P = 0.74). The lowest MFR in very low likelihood patients in any given vascular territory was 2.25 for QPET, 2.13 for syngo MBF, and 2.23 for PMOD. Different implementations of 1- and 2-compartment models demonstrate an excellent correlation in MFR for each vascular territory, with similar mean MFR values.

  13. Exploring Hydrofluorocarbons as Groundwater Age Tracers (Invited)

    Science.gov (United States)

    Haase, K. B.; Busenberg, E.; Plummer, L. N.; Casile, G.; Sanford, W. E.

    2013-12-01

    Groundwater dating tracers are an essential tool for analyzing hydrologic conditions in groundwater systems. Commonly used tracers for dating post-1940's groundwater include sulfur hexafluoride (SF6), chlorofluorocarbons (CFCs), 3H-3He, and other isotopic tracers (85Kr, δ2H and δ18O isotopes, etc.). Each tracer carries a corresponding set of advantages and limitations imposed by field, analytical, and interpretive methods. Increasing the number available tracers is appealing, particularly if they possess inert chemical properties and unique temporal emission histories from other tracers. Atmospherically derived halogenated trace gases continue to hold untapped potential for new tracers, as they are generally inert and their emission histories are well documented. SF5CF3, and CFC-13 were previously shown to have application as dating tracers, though their low mixing ratios and low solubility require large amounts of water to be degassed for their quantification. Two related groups of compounds, hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are hypothesized to be potential age tracers, having similar mixing ratios to the CFCs and relatively high solubility. However, these compounds yield gas chromatography electron capture detector (GC-ECD) responses that are 10-2 -10-5 less than CFC-12, making purge and trap or field stripping GC-ECD approaches impractical. Therefore, in order to use dissolved HCFCs and HFCs as age tracers, different approaches are needed. To solve this problem, we developed an analytical method that uses an atomic emission detector (GC-AED) in place of an ECD to detect fluorinated compounds. In contrast to the ECD, the AED is a universally sensitive, highly linear, elementally specific detector. The new GC-AED system is being used to measure chlorodifluoromethane (HCFC-22), 1,1,1,2-tetrafluoroethane (HFC-134a), and other fluorinated compounds in one liter water samples to study their potential as age dating tracers. HCFC-22 is a

  14. Scintigraphic characteristics of experimental myocardial infarct extension

    International Nuclear Information System (INIS)

    Kronenberg, M.W.; Wooten, N.E.; Friesinger, G.C.; Page, D.L.; Higgins, S.B.; Collins, J.C.; O'Connor, J.L.; Price, R.R.; Brill, A.B.

    1979-01-01

    Technetium-99m-stannous pyrophosphate scintiphotos were evaluated for diagnosing and quantitating myocardial infarct (MI) extension in sedated dogs. Infarction and extension were produced by serial left anterior descending coronary artery ligations at 0 and 48 hours. We compared serial scintiphoto data with regional myocardial blood flow (MBF) (microsphere technique) and infarct histopathology. In eight control dogs, the scintigraphic MI area was stable at 24, 48, and 72 hours. In each of 11 dogs undergoing extension, the MI area increased after the 48-hour occlusion, averaging a 48.9% increase (p < 0.001). Grossly, most extensions were mixtures of confluent necrosis and moderate (patchy) necrosis. MBF to confluent infarct tissue decreased significantly, allowing the documentation of extension by totaling the grams of newly flow-deprived tissue, but patchy infarct tissue had little flow deprivation, making it difficult to quantitate this type of extension accurately by flow criteria alone. Rarely, extension could be diagnosed using conventional histologic criteria. We concluded that the scintiphoto MI area was related quantitatively to infarct weight in both control and extension. However, it was not possible to determine that an increase in the MI scintiphoto area was an accurate predictor of the degree of extension using independent flow or pathologic criteria

  15. Oxygen diffusion in a network model of the myocardial microcirculation

    NARCIS (Netherlands)

    Wieringa, P. A.; Stassen, H. G.; van Kan, J. J.; Spaan, J. A.

    1993-01-01

    Oxygen supply was studied in a three-dimensional capillary network model of the myocardial microcirculation. Capillary networks were generated using one common strategy to locate the capillary branchings and segments, arterioles and venules. Flow paths developed with different capillary flow

  16. Biokinetics of radiolabeled Iodophenylpentadecanoic acid (I-123-IPPA) and thallium-201 in a rabbit model of chronic myocardial infarction measured using a series of thermoluminescent dosimeters

    Science.gov (United States)

    Medich, David Christopher

    1997-09-01

    The biokinetics of Iodophenylpentadecanoic acid (123I-IPPA) during a chronic period of myocardial infarction were determined and compared to 201Tl. IPPA was assessed as a perfusion and metabolic tracer in the scintigraphic diagnosis of coronary artery disease. The myocardial clearance kinetics were measured by placing a series of thermoluminescent dosimeters (TLDs) on normal and infarcted tissue to measure the local myocardial activity content over time. The arterial blood pool activity was fit to a bi-exponential function for 201Tl and a tri-exponential function for 123I-IPPA to estimate the left ventricle contribution to TLD response. At equilibrium, the blood pool contribution was estimated experimentally to be less than 5% of the total TLD response. The method was unable to resolve the initial uptake of the imaging agent due in part to the 2 minute TLD response integration time and in part to the 30 second lag time for the first TLD placement. A noticeable disparity was observed between the tracer concentrations of IPPA in normal and ischemic tissue of approximately 2:1. The fitting parameters (representing the biokinetic eigenvalue rate constants) were related to the fundamental rate constants of a recycling biokinetic model. The myocardial IPPA content within normal tissue was elevated after approximately 130 minutes post injection. This phenomenon was observed in all but one (950215) of the IPPA TLD kinetics curves.

  17. Effects of dipyridamole and aminophylline on hemodynamics, regional myocardial blood flow and thallium-201 washout in the setting of a critical coronary stenosis

    International Nuclear Information System (INIS)

    Granato, J.E.; Watson, D.D.; Belardinelli, L.; Cannon, J.M.; Beller, G.A.

    1990-01-01

    Experiments were performed to characterize the interaction of intravenous dipyridamole and aminophylline on thallium-201 transport kinetics, regional myocardial blood flow and systemic hemodynamics in the presence of a critical coronary artery stenosis. In 12 dogs with a critical left anterior descending coronary artery stenosis, arterial pressure decreased from a mean value (+/- SEM) of 107 +/- 6 to 94 +/- 3 mm Hg and distal left anterior descending artery pressure decreased from 70 +/- 7 to 55 +/- 4 mm Hg after intravenous administration of dipyridamole. In the left anterior descending perfusion zone, the endocardial/epicardial flow ratio decreased from 0.70 to 0.36 and the intrinsic thallium washout rate was significantly prolonged. Intravenous aminophylline reversed the dipyridamole-induced systemic hypotension and transmural coronary steal and restored the thallium washout rate to baseline values. In six other dogs, aminophylline alone resulted in no alterations in systemic and coronary hemodynamics or regional myocardial blood flow. As expected, dipyridamole-induced vasodilation and coronary steal were prevented by aminophylline pretreatment. These data show that in a canine model of partial coronary stenosis, systemic hypotension, adverse regional flow effects and prolonged thallium-201 washout consequent to intravenously administered dipyridamole are promptly reversed by intravenous aminophylline administration. Aminophylline alone had no significant hemodynamic and coronary flow effects. This study provides further insight into the altered thallium kinetics occurring as a consequence of dipyridamole-induced vasodilation and suggests that the prompt reversal of symptoms and signs of ischemia with aminophylline in patients receiving intravenous dipyridamole for clinical imaging studies probably reflects the reversal of transmural coronary steal

  18. Test-retest repeatability of myocardial blood flow and infarct size using {sup 11}C-acetate micro-PET imaging in mice

    Energy Technology Data Exchange (ETDEWEB)

    Croteau, Etienne; Renaud, Jennifer M.; McDonald, Matthew; Klein, Ran; DaSilva, Jean N.; Beanlands, Rob S.B.; DeKemp, Robert A. [University of Ottawa Heart Institute, National Cardiac PET Centre, Ottawa, Ontario (Canada)

    2015-09-15

    Global and regional responses of absolute myocardial blood flow index (iMBF) are used as surrogate markers to assess response to therapies in coronary artery disease. In this study, we assessed the test-retest repeatability of iMBF imaging, and the accuracy of infarct sizing in mice using {sup 11}C-acetate PET. {sup 11}C-Acetate cardiac PET images were acquired in healthy controls, endothelial nitric oxide synthase (eNOS) knockout transgenic mice, and mice after myocardial infarction (MI) to estimate global and regional iMBF, and myocardial infarct size compared to {sup 18}F-FDG PET and ex-vivo histology results. Global test-retest iMBF values had good coefficients of repeatability (CR) in healthy mice, eNOS knockout mice and normally perfused regions in MI mice (CR = 1.6, 2.0 and 1.5 mL/min/g, respectively). Infarct size measured on {sup 11}C-acetate iMBF images was also repeatable (CR = 17 %) and showed a good correlation with the infarct sizes found on {sup 18}F-FDG PET and histopathology (r{sup 2} > 0.77; p < 0.05). {sup 11}C-Acetate micro-PET assessment of iMBF and infarct size is repeatable and suitable for serial investigation of coronary artery disease progression and therapy. (orig.)

  19. Waste tank ventilation rates measured with a tracer gas method

    International Nuclear Information System (INIS)

    Huckaby, J.L.; Evans, J.C.; Sklarew, D.S.; Mitroshkov, A.V.

    1998-08-01

    Passive ventilation with the atmosphere is used to prevent accumulation of waste gases and vapors in the headspaces of 132 of the 177 high-level radioactive waste Tanks at the Hanford Site in Southeastern Washington State. Measurements of the passive ventilation rates are needed for the resolution of two key safety issues associated with the rates of flammable gas production and accumulation and the rates at which organic salt-nitrate salt mixtures dry out. Direct measurement of passive ventilation rates using mass flow meters is not feasible because ventilation occurs va multiple pathways to the atmosphere (i.e., via the filtered breather riser and unsealed tank risers and pits), as well as via underground connections to other tanks, junction boxes, and inactive ventilation systems. The tracer gas method discussed in this report provides a direct measurement of the rate at which gases are removed by ventilation and an indirect measurement of the ventilation rate. The tracer gas behaves as a surrogate of the waste-generated gases, but it is only diminished via ventilation, whereas the waste gases are continuously released by the waste and may be subject to depletion mechanisms other than ventilation. The fiscal year 1998 tracer studies provide new evidence that significant exchange of air occurs between tanks via the underground cascade pipes. Most of the single-shell waste tanks are connected via 7.6-cm diameter cascade pipes to one or two adjacent tanks. Tracer gas studies of the Tank U-102/U-103 system indicated that the ventilation occurring via the cascade line could be a significant fraction of the total ventilation. In this two-tank cascade, air evidently flowed from Tank U-103 to Tank U-102 for a time and then was observed to flow from Tank U-102 to Tank U-103

  20. Tracer preparate and method for its production

    International Nuclear Information System (INIS)

    Pratt, F.P.; Gagnon, D.

    1978-01-01

    The injectable tracer preparate for investigations to determine the blood flow in organs or the effect of drugs on the blood flow consists of a core of ion exchanger resin coated with polyfuran or a polymer which is the reaction product of a monomer catalysable by acid or base. The nuclei have a diameter of 10 to 200 micron, the coating thickness is between 1 and 3 micron. Ions of Ce 141, Cr 51, Sr 85, Sr 46 or Co 57 of strength 0.1-100 millicurie are adsorbed on the nucleus. (DG) [de

  1. The review of myocardial positron emission computed tomography and positron imaging by gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Ohtake, Tohru [Tokyo Univ. (Japan). Faculty of Medicine

    1998-04-01

    To measure myocardial blood flow, Nitrogen-13 ammonia, Oxygen-15 water, Rubidium-82 and et al. are used. Each has merit and demerit. By measuring myocardial coronary flow reserve, the decrease of flow reserve during dipyridamole in patients with hypercholesterolemia or diabetes mellitus without significant coronary stenosis was observed. The possibility of early detection of atherosclerosis was showed. As to myocardial metabolism, glucose metabolism is measured by Fluorine-18 fluorodeoxyglucose (FDG), and it is considered as useful for the evaluation of myocardial viability. We are using FDG to evaluate insulin resistance during insulin clamp in patients with diabetes mellitus by measuring glucose utilization rate of myocardium and skeletal muscle. FFA metabolism has been measured by {sup 11}C-palmitate, but absolute quantification has not been performed. Recently the method for absolute quantification was reported, and new radiopharmaceutical {sup 18}F-FTHA was reported. Oxygen metabolism has been estimated by {sup 11}C-acetate. Myocardial viability, cardiac efficiency was evaluated by oxygen metabolism. As to receptor or sympathetic nerve end, cardiac insufficiency or cardiac transplantation was evaluated. Imaging of positron emitting radiopharmaceutical by gamma camera has been performed. Collimator method is clinically useful for cardiac imaging of viability study. (author). 54 refs.

  2. Development of radioisotope tracer technology and nucleonic control system

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Joon Ha; Lee, Myun Joo; Jung, Sung Hee and others

    1999-04-01

    The purpose of this study is to develop the radioisotope tracer technology, which can be used in solving industrial and environmental problems and basic technology of nuclear control systems that are widely used for automation of industrial plants, and to build a strong tracer group to support the local industries. In relation to the tracer technology, the data acquisition system, the column scanning equipment and the detection pig for a leakage test have been developed. In order to use in analyzing data of tracer experiments, a computer program for the analysis of residence time distribution has been created as well. These results were utilized in developing the tracer technologies, such as the column scanning, the flow measurement using the dilution method, the simultaneous monitoring rotational movement of piston rings and the optimization of a waste water treatment facility, and the technologies were successfully demonstrated in the local industrial. The stripper of RFCC reactor has been examined to find an unwanted structure in it by imminent request from the industry. Related to the development of nucleonic control system, the state of art report on the technology has been written and an equipment for the analysis of asphalt content has been developed. (author)

  3. Deep groundwater flow systems and their characterization in single-well settings by ''push-pull'' tracer tests

    International Nuclear Information System (INIS)

    Hebig-Schubert, Klaus

    2014-01-01

    This thesis demonstrates the growing importance of deep groundwater research and the increasing demand for the development of suitable single-well test methods. At the forefront of the research on groundwater in the deep underground, radioactive waste disposal in deep geological repositories, CO 2 storage, geothermal energy supply, and aquifer storage and recovery systems (ASR) are on the agenda. The developments of suitable methods for investigating these resources are a main target. Currently available methods show considerable limitations. Accordingly, comprehensive methods for the hydraulic and hydrochemical characterization of deeper aquifers with single-well access are needed. Therefore, the goal of this PhD thesis was to identify, test, and enhance potentially suitable single-well methods for characterization of groundwater flow and solute transport in such settings. For this, several Single-Well Injection-Withdrawal (''push-pull'') tracer tests were applied at the Hamasato field site (Horonobe, Japan) in a ∝100 m deep groundwater monitoring well. Aim was to characterize the impact of a dynamic saltwater-freshwater interface on a coastal aquifer. Based on the experiences of the first methodological test, a second field campaign was conducted. This campaign focused on a systematic evaluation of the push-pull tracer test method for the first time at all. The experiments focused on the investigation of the so-called ''chaser'' and its impact on the test results. The chaser is a specific part of many push-pull tracer tests setups. From these experiments, a specific test design for the investigation of the saltwater-freshwater interface in a single-well setting was developed. The application of this design on questions regarding different fluids within the same system, e.g. different mineralized fluids (saltwater-freshwater-interface, ASR) or temperatures (geothermal research), are promising future approaches for this

  4. Deep groundwater flow systems and their characterization in single-well settings by ''push-pull'' tracer tests

    Energy Technology Data Exchange (ETDEWEB)

    Hebig-Schubert, Klaus

    2014-11-21

    This thesis demonstrates the growing importance of deep groundwater research and the increasing demand for the development of suitable single-well test methods. At the forefront of the research on groundwater in the deep underground, radioactive waste disposal in deep geological repositories, CO{sub 2} storage, geothermal energy supply, and aquifer storage and recovery systems (ASR) are on the agenda. The developments of suitable methods for investigating these resources are a main target. Currently available methods show considerable limitations. Accordingly, comprehensive methods for the hydraulic and hydrochemical characterization of deeper aquifers with single-well access are needed. Therefore, the goal of this PhD thesis was to identify, test, and enhance potentially suitable single-well methods for characterization of groundwater flow and solute transport in such settings. For this, several Single-Well Injection-Withdrawal (''push-pull'') tracer tests were applied at the Hamasato field site (Horonobe, Japan) in a ∝100 m deep groundwater monitoring well. Aim was to characterize the impact of a dynamic saltwater-freshwater interface on a coastal aquifer. Based on the experiences of the first methodological test, a second field campaign was conducted. This campaign focused on a systematic evaluation of the push-pull tracer test method for the first time at all. The experiments focused on the investigation of the so-called ''chaser'' and its impact on the test results. The chaser is a specific part of many push-pull tracer tests setups. From these experiments, a specific test design for the investigation of the saltwater-freshwater interface in a single-well setting was developed. The application of this design on questions regarding different fluids within the same system, e.g. different mineralized fluids (saltwater-freshwater-interface, ASR) or temperatures (geothermal research), are promising future approaches for

  5. Development of activable tracers for application in secondary recovering in petroleum reservoirs

    International Nuclear Information System (INIS)

    Martins, Polyana Fabricia Fernandes; Moreira, Rubens Martins . Servico de Meio Ambiente e Tecnicas Nucleares.

    2007-01-01

    Nuclear methods are instrumental in describing detailed flow patterns and other features of oil reservoirs that are unattainable to other methods. Tracer studies in oil fields are performed in a net of injection and producing wells. Thus, the use of only one tracer species would not discriminate the contributions of distinct injection wells to the output of a given production well. Hence, a multi-tracer experiment is required, and the use of activable tracers, capable of being measured by neutron activation analysis (NAA) is here proposed. As additional tracer choices lanthanum (La) and europium (Eu) were chosen from the rare earth series due to their large neutron cross sections and general availability. In order to decrease losses to the oil phase and the retardation of the tracer relatively to the aqueous phase, these elements were complexed with organic chelating ligands: the polyaminocarboxylic acids EDTA, DTPA and DOTA. Infrared spectrometry was used to check complexation. In order to check the partition of the tracer between the aqueous and organic phases, tests were carried stirring the two phases together and measuring the tracer concentrations in the aqueous phase; the partition coefficient (Kao) was then calculated for all the combinations of the two lanthanides and the three ligands. Tests in which the tracer was continuously pumped through reservoir rock samples were also carried out using tritiated water as a reference tracer and the complexed lanthanides. (author)

  6. Perfusion scintigraphy in acute myocardial infarction

    International Nuclear Information System (INIS)

    Schricke, U.; Schwaiger, M.; Kastrati, A.; Schoemig, A.

    1999-01-01

    The Tc-99m sestamibi perfusion SPECT scintigraphy in acute myocardial infarction is a feasible method to assess the size of area at risk and the residual blood flow to this area as the most important determinants of final infarct size without any delay in treatment. In combination with a follow-up study final infarct size as well as myocardial salvage can be quantified. Clinical indications for the use of Tc-99m sestamibi scintigraphy are the noninvasive identification of arterial occlusion in patients suspected to acute myocardial infarction without electrocardiographic ST-elevation and the assessment of reperfusion success. In clinical trials Tc-99m sestamibi scintigraphy has proven to be a useful method to assess the impact of varying reperfusion therapies. The present review article discusses the indication, the study protocol, the interpretation of results and the clinical and scientifically importance of this method. (orig.) [de

  7. Sex differences in the tracer distribution on stress thallium-201 imaging, (1)

    International Nuclear Information System (INIS)

    Tamaki, Nagara; Koda, Hideki; Adachi, Yukihide; Sugihara, Takao; Kato, Mihoko; Tanaka, Nobuyuki; Tamari, Kimimasa.

    1988-01-01

    To determine the sex differences in the tracer distribution on stress thallium-201 imaging, the studies of 18 normal males and 18 normal females were subjected to quantitative circumferential profile analysis in each projection image. Although the exercise duration was shorter in females (11±3 min) than in males (14±3 min) (p<0.01), the peak heart rate, peak systolic pressure and the lung-to-myocardial count ratio were similar between them. The averaged profile curves in female showed a significant reduction in tracer uptake in anterior and upper septal regions, particularly in the study of lateral view, which may be attributed to breast attenuation. In addition, the percent washout of thallium in 3 hours was higher in females (48±8%) than in males (43±7%) (p<0.01), particularly in the study of anterior view. We conclude that important differences in the pattern of thallium uptake and washout between males and females should be considered for interpretation of stress thallium imaging. (author)

  8. High fat diet-induced glucose intolerance impairs myocardial function, but not myocardial perfusion during hyperaemia: a pilot study

    Directory of Open Access Journals (Sweden)

    van den Brom Charissa E

    2012-06-01

    Full Text Available Abstract Background Glucose intolerance is a major health problem and is associated with increased risk of progression to type 2 diabetes mellitus and cardiovascular disease. However, whether glucose intolerance is related to impaired myocardial perfusion is not known. The purpose of the present study was to study the effect of diet-induced glucose intolerance on myocardial function and perfusion during baseline and pharmacological induced hyperaemia. Methods Male Wistar rats were randomly exposed to a high fat diet (HFD or control diet (CD (n = 8 per group. After 4 weeks, rats underwent an oral glucose tolerance test. Subsequently, rats underwent (contrast echocardiography to determine myocardial function and perfusion during baseline and dipyridamole-induced hyperaemia (20 mg/kg for 10 min. Results Four weeks of HFD feeding resulted in glucose intolerance compared to CD-feeding. Contractile function as represented by fractional shortening was not altered in HFD-fed rats compared to CD-fed rats under baseline conditions. However, dipyridamole increased fractional shortening in CD-fed rats, but not in HFD-fed rats. Basal myocardial perfusion, as measured by estimate of perfusion, was similar in CD- and HFD-fed rats, whereas dipyridamole increased estimate of perfusion in CD-fed rats, but not in HFD-fed rats. However, flow reserve was not different between CD- and HFD-fed rats. Conclusions Diet-induced glucose intolerance is associated with impaired myocardial function during conditions of hyperaemia, but myocardial perfusion is maintained. These findings may result in new insights into the effect of glucose intolerance on myocardial function and perfusion during hyperaemia.

  9. Quantitative myocardial perfusion by O-15-water PET

    DEFF Research Database (Denmark)

    Thomassen, Anders; Petersen, Henrik; Johansen, Allan

    2015-01-01

    AIMS: Reporting of quantitative myocardial blood flow (MBF) is typically performed in standard coronary territories. However, coronary anatomy and myocardial vascular territories vary among individuals, and a coronary artery may erroneously be deemed stenosed or not if territorial demarcation...... disease (CAD). METHODS AND RESULTS: Forty-four patients with suspected CAD were included prospectively and underwent coronary CT-angiography and quantitative MBF assessment with O-15-water PET followed by invasive, quantitative coronary angiography, which served as reference. MBF was calculated...

  10. A Systematic Method For Tracer Test Analysis: An Example Using Beowawe Tracer Data

    Energy Technology Data Exchange (ETDEWEB)

    G. Michael Shook

    2005-01-01

    Quantitative analysis of tracer data using moment analysis requires a strict adherence to a set of rules which include data normalization, correction for thermal decay, deconvolution, extrapolation, and integration. If done correctly, the method yields specific information on swept pore volume, flow geometry and fluid velocity, and an understanding of the nature of reservoir boundaries. All calculations required for the interpretation can be done in a spreadsheet. The steps required for moment analysis are reviewed in this paper. Data taken from the literature is used in an example calculation.

  11. Dynamic myocardial perfusion in a porcine balloon-induced ischemia model using a prototype spectral detector CT

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Fares, Anas; Levi, Jacob; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2015-03-01

    Myocardial CT perfusion (CTP) imaging is an application that should greatly benefit from spectral CT through the significant reduction of beam hardening (BH) artifacts using mono-energetic (monoE) image reconstructions. We used a prototype spectral detector CT (SDCT) scanner (Philips Healthcare) and developed advanced processing tools (registration, segmentation, and deconvolution-based flow estimation) for quantitative myocardial CTP in a porcine ischemia model with different degrees of coronary occlusion using a balloon catheter. The occlusion severity was adjusted with fractional flow reserve (FFR) measurements. The SDCT scanner is a single source, dual-layer detector system, which allows simultaneous acquisitions of low and high energy projections, hence enabling accurate projection-based material decomposition and effective reduction of BH-artifacts. In addition, the SDCT scanner eliminates partial scan artifacts with fast (0.27s), full gantry rotation acquisitions. We acquired CTP data under different hemodynamic conditions and reconstructed conventional 120kVp images and projection-based monoenergetic (monoE) images for energies ranging from 55keV-to-120keV. We computed and compared myocardial blood flow (MBF) between different reconstructions. With balloon completely deflated (FFR=1), we compared the mean attenuation in a myocardial region of interest before iodine arrival and at peak iodine enhancement in the left ventricle (LV), and we found that monoE images at 70keV effectively minimized the difference in attenuation, due to BH, to less than 1 HU compared to 14 HU with conventional 120kVp images. Flow maps under baseline condition (FFR=1) were more uniform throughout the myocardial wall at 70keV, whereas with 120kVp data about 12% reduction in blood flow was noticed on BH-hypoattenuated areas compared to other myocardial regions. We compared MBF maps at different keVs under an ischemic condition (FFR < 0.7), and we found that flow

  12. Tracer tests and image analysis of biological clogging in a two-dimentsional sandbox experiment

    DEFF Research Database (Denmark)

    Kildsgaard, J.; Engesgaard, Peter Knudegaard

    2002-01-01

    A two-dimensional flow experiment on biological clogging was carried out by biostimulating a sandbox packed with sand inoculated with bacteria. Biostimulation. consisted of continuously injecting nutrients (acetate and nitrate). Clogging was visualized by frequently carrying out colored tracer...... experiments using Brilliant Blue. The tracer experiments were recorded with a digital camera and converted to concentration maps using an image-analysis method that revealed in detail the complex spreading pattern surrounding clogged areas. Clogging resulted in a finger-like spreading of the tracer around...

  13. Transdiaphragmatic transport of tracer albumin from peritoneal to pleural liquid measured in rats.

    Science.gov (United States)

    Lai-Fook, Stephen J; Houtz, Pamela K; Jones, Philip D

    2005-12-01

    In conscious Wistar-Kyoto rats, we studied the uptake of radioactive tracer (125)I-albumin into the pleural space and circulation after intraperitoneal (IP) injections with 1 or 5 ml of Ringer solution (3 g/dl albumin). Postmortem, we sampled pleural liquid, peritoneal liquid, and blood plasma 2-48 h after IP injection and measured their radioactivity and protein concentration. Tracer concentration was greater in pleural liquid than in plasma approximately 3 h after injection with both IP injection volumes. This behavior indicated transport of tracer through the diaphragm into the pleural space. A dynamic analysis of the tracer uptake with 5-ml IP injections showed that at least 50% of the total pleural flow was via the diaphragm. A similar estimate was derived from an analysis of total protein concentrations. Both estimates were based on restricted pleural capillary filtration and unrestricted transdiaphragmatic transport. The 5-ml IP injections did not change plasma protein concentration but increased pleural and peritoneal protein concentrations from control values by 22 and 30%, respectively. These changes were consistent with a small (approximately 8%) increase in capillary filtration and a small (approximately 20%) reduction in transdiaphragmatic flow from control values, consistent with the small (3%) decrease in hydration measured in diaphragm muscle. Thus the pleural uptake of tracer via the diaphragm with the IP injections occurred by the near-normal transport of liquid and protein.

  14. Prevalence of silent myocardial ischaemia during exercise stress testing. Its relation to effort tolerance and myocardial perfusion abnormalities.

    Science.gov (United States)

    Fragasso, G; Sciammarella, M G; Rossetti, E E; Xuereb, R G; Xuereb, M; Bonetti, F; Carandente, O M; Margonato, A; Chierchia, S L

    1992-07-01

    The number of underperfused myocardial segments, the extent of coronary artery disease and the severity of impairment of coronary flow reserve were compared in 147 consecutive patients exhibiting painful or painless ischaemic ST segment depression on exercise testing. Of 147 patients, only 61 (41%) experienced angina (group 1) whilst 86 (59%) did not (group 2). In the two groups coronary disease was comparable for both extent and distribution, and neither the location of transient perfusion defects nor their relation to areas of old myocardial necrosis appeared to influence the presence or absence of chest pain. However, exercise duration, exercise time and rate-pressure product at the beginning of ischaemia were lower in group 1. Furthermore, a greater proportion of asymptomatic patients had only one ischaemic segment on 99mTc-MIBI perfusion scintigraphy. We conclude that: (1) in patients with effort angina and coronary disease, the incidence of electrocardiographic silent ischaemic events induced by exercise is similar to that observed in studies based on continuous ECG monitoring. (2) Exertional angina is more frequently associated with greater ischaemic areas and with more severe degrees of impairment of residual coronary flow reserve. (3) The presence of an old myocardial infarction does not appear to influence the incidence of ischaemic cardiac pain.

  15. Tagging moisture sources with Lagrangian and inertial tracers: application to intense atmospheric river events

    Directory of Open Access Journals (Sweden)

    V. Pérez-Muñuzuri

    2018-06-01

    Full Text Available Two Lagrangian tracer tools are evaluated for studies on atmospheric moisture sources and pathways. In these methods, a moisture volume is assigned to each particle, which is then advected by the wind flow. Usual Lagrangian methods consider this volume to remain constant and the particle to follow flow path lines exactly. In a different approach, the initial moisture volume can be considered to depend on time as it is advected by the flow due to thermodynamic processes. In this case, the tracer volume drag must be taken into account. Equations have been implemented and moisture convection was taken into account for both Lagrangian and inertial models. We apply these methods to evaluate the intense atmospheric rivers that devastated (i the Pacific Northwest region of the US and (ii the western Iberian Peninsula with flooding rains and intense winds in early November 2006 and 20 May 1994, respectively. We note that the usual Lagrangian method underestimates moisture availability in the continent, while active tracers achieve more realistic results.

  16. Clinical usefulness of {sup 123}I-BMIPP myocardial SPECT in collagen disease

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Kazuki; Zen, Kan [Asahi Univ., Gifu (Japan). Murakami Memorial Hospital; Sugihara, Hiroki (and others)

    2000-07-01

    This study was designed to evaluate the clinical usefulness of {sup 123}I-BMIPP myocardial SPECT for detecting cardiac involvement in patients with collagen disease. We studied 12 patients with systemic lupus erythematosus (SLE), 8 with progressive systemic sclerosis (PSS), 6 with polymyositis/dermatomyositis (PM/DM) and 3 with allergic granulomatosis and angiitis (AGA). A 111 MBq of {sup 123}I-BMIPP was intravenously injected at rest, and SPECT images were obtained at 15 min after the injection. Seven of 12 SLE, 6 of 8 PSS, 3 of 6 PM/DM and all 3 AGA patients showed an abnormal tracer uptake. The left ventricular ejection fraction was inversely correlated with a BMIPP abnormality. The regional wall motion abnormality was reduced in regions with reduced tracer uptake. These findings suggest that {sup 123}I-BMIPP imaging could be useful for assessment of cardiac involvement in patients with collagen disease. (author)

  17. Simultaneous 3D tracking of passive tracers and microtubule bundles in an active gel

    Science.gov (United States)

    Fan, Yi; Breuer, Kenneth S.; Fluids Team

    Kinesin-driven microtubule bundles generate a spontaneous flow in unconfined geometries. They exhibit properties of active matter, including the emergence of collective motion, reduction of apparent viscosity and consumption of local energy. Here we present results from 3D tracking of passive tracers (using Airy rings and 3D scanning) synchronized with 3D measurement of the microtubule bundles motion. This technique is applied to measure viscosity variation and collective flow in a confined geometry with particular attention paid to the self-pumping system recently reported by Wu et al. (2016). Results show that the viscosity in an equilibrium microtubule network is around half that of the isotropic unbundled microtubule solution. Cross-correlations of the active microtubule network and passive tracers define a neighborhood around microtubule bundles in which passive tracers are effectively transported. MRSEC NSF.

  18. Description and results of tracer tests conducted for a deep fracture zone within granitic rock at the Leuggern borehole

    International Nuclear Information System (INIS)

    Spane, F.A. jr.

    1990-09-01

    A tracer test program was planned at the Leuggern borehole, to provide hydrogeologic information concerning the fracture zone(s) intersected within the depth interval 1,634.9 - 1,688.9 m. The original design of the tracer-dilution test was to: establish a uniform tracer concentration within the test system, and then monitor (at ground surface) the decline of tracer concentration within the circulated test system fluid. Analysis of the tracer concentration decline pattern was expected to provide an estimate of the natural lateral flux and lateral hydraulic gradient for the isolated test interval. A later pump-back test was also designed to recover tracer that had been 'flushed' into the test section, during the previous closed-circulation period. Analysis of the tracer recovery pattern was expected to provide an estimate of the dispersivity within the intersected fracture system. Results obtained from 'arrival-time' information during the Eosin and Naphtionat injection/recovery phases indicate a downward vertical flow of approximately 195-225 ml/min in the isolated interval, from an analysis of the dilution levels of Uranin and Eosin during the injection/recovery periods, and review of field data, the top of the upper inflow zone was determined to be approximately 13 m below the top flow line and the bottom of the outflow zone to be approximately 3 to 5 meters above the bottom flow line. (author) 30 figs., tabs., 42 refs

  19. Estimation of time-variable fast flow path chemical concentrations for application in tracer-based hydrograph separation analyses

    Science.gov (United States)

    Kronholm, Scott C.; Capel, Paul D.

    2016-01-01

    Mixing models are a commonly used method for hydrograph separation, but can be hindered by the subjective choice of the end-member tracer concentrations. This work tests a new variant of mixing model that uses high-frequency measures of two tracers and streamflow to separate total streamflow into water from slowflow and fastflow sources. The ratio between the concentrations of the two tracers is used to create a time-variable estimate of the concentration of each tracer in the fastflow end-member. Multiple synthetic data sets, and data from two hydrologically diverse streams, are used to test the performance and limitations of the new model (two-tracer ratio-based mixing model: TRaMM). When applied to the synthetic streams under many different scenarios, the TRaMM produces results that were reasonable approximations of the actual values of fastflow discharge (±0.1% of maximum fastflow) and fastflow tracer concentrations (±9.5% and ±16% of maximum fastflow nitrate concentration and specific conductance, respectively). With real stream data, the TRaMM produces high-frequency estimates of slowflow and fastflow discharge that align with expectations for each stream based on their respective hydrologic settings. The use of two tracers with the TRaMM provides an innovative and objective approach for estimating high-frequency fastflow concentrations and contributions of fastflow water to the stream. This provides useful information for tracking chemical movement to streams and allows for better selection and implementation of water quality management strategies.

  20. Neural network approaches to tracer identification as related to PIV research

    International Nuclear Information System (INIS)

    Seeley, C.H. Jr.

    1992-12-01

    Neural networks have become very powerful tools in many fields of interest. This thesis examines the application of neural networks to another rapidly growing field flow visualization. Flow visualization research is used to experimentally determine how fluids behave and to verify computational results obtained analytically. A form of flow visualization, particle image velocimetry (PIV). determines the flow movement by tracking neutrally buoyant particles suspended in the fluid. PIV research has begun to improve rapidly with the advent of digital imagers, which can quickly digitize an image into arrays of grey levels. These grey level arrays are analyzed to determine the location of the tracer particles. Once the particles positions have been determined across multiple image frames, it is possible to track their movements, and hence, the flow of the fluid. This thesis explores the potential of several different neural networks to identify the positions of the tracer particles. Among these networks are Backpropagation, Kohonen (counter-propagation), and Cellular. Each of these algorithms were employed in their basic form, and training and testing were performed on a synthetic grey level array. Modifications were then made to them in attempts to improve the results

  1. Neural network approaches to tracer identification as related to PIV research

    Energy Technology Data Exchange (ETDEWEB)

    Seeley, C.H. Jr.

    1992-12-01

    Neural networks have become very powerful tools in many fields of interest. This thesis examines the application of neural networks to another rapidly growing field flow visualization. Flow visualization research is used to experimentally determine how fluids behave and to verify computational results obtained analytically. A form of flow visualization, particle image velocimetry (PIV). determines the flow movement by tracking neutrally buoyant particles suspended in the fluid. PIV research has begun to improve rapidly with the advent of digital imagers, which can quickly digitize an image into arrays of grey levels. These grey level arrays are analyzed to determine the location of the tracer particles. Once the particles positions have been determined across multiple image frames, it is possible to track their movements, and hence, the flow of the fluid. This thesis explores the potential of several different neural networks to identify the positions of the tracer particles. Among these networks are Backpropagation, Kohonen (counter-propagation), and Cellular. Each of these algorithms were employed in their basic form, and training and testing were performed on a synthetic grey level array. Modifications were then made to them in attempts to improve the results.

  2. Direct parametric reconstruction in dynamic PET myocardial perfusion imaging: in vivo studies

    Science.gov (United States)

    Petibon, Yoann; Rakvongthai, Yothin; El Fakhri, Georges; Ouyang, Jinsong

    2017-05-01

    Dynamic PET myocardial perfusion imaging (MPI) used in conjunction with tracer kinetic modeling enables the quantification of absolute myocardial blood flow (MBF). However, MBF maps computed using the traditional indirect method (i.e. post-reconstruction voxel-wise fitting of kinetic model to PET time-activity-curves-TACs) suffer from poor signal-to-noise ratio (SNR). Direct reconstruction of kinetic parameters from raw PET projection data has been shown to offer parametric images with higher SNR compared to the indirect method. The aim of this study was to extend and evaluate the performance of a direct parametric reconstruction method using in vivo dynamic PET MPI data for the purpose of quantifying MBF. Dynamic PET MPI studies were performed on two healthy pigs using a Siemens Biograph mMR scanner. List-mode PET data for each animal were acquired following a bolus injection of ~7-8 mCi of 18F-flurpiridaz, a myocardial perfusion agent. Fully-3D dynamic PET sinograms were obtained by sorting the coincidence events into 16 temporal frames covering ~5 min after radiotracer administration. Additionally, eight independent noise realizations of both scans—each containing 1/8th of the total number of events—were generated from the original list-mode data. Dynamic sinograms were then used to compute parametric maps using the conventional indirect method and the proposed direct method. For both methods, a one-tissue compartment model accounting for spillover from the left and right ventricle blood-pools was used to describe the kinetics of 18F-flurpiridaz. An image-derived arterial input function obtained from a TAC taken in the left ventricle cavity was used for tracer kinetic analysis. For the indirect method, frame-by-frame images were estimated using two fully-3D reconstruction techniques: the standard ordered subset expectation maximization (OSEM) reconstruction algorithm on one side, and the one-step late maximum a posteriori (OSL-MAP) algorithm on the other

  3. Direct parametric reconstruction in dynamic PET myocardial perfusion imaging: in-vivo studies

    Science.gov (United States)

    Petibon, Yoann; Rakvongthai, Yothin; Fakhri, Georges El; Ouyang, Jinsong

    2017-01-01

    Dynamic PET myocardial perfusion imaging (MPI) used in conjunction with tracer kinetic modeling enables the quantification of absolute myocardial blood flow (MBF). However, MBF maps computed using the traditional indirect method (i.e. post-reconstruction voxel-wise fitting of kinetic model to PET time-activity-curves -TACs) suffer from poor signal-to-noise ratio (SNR). Direct reconstruction of kinetic parameters from raw PET projection data has been shown to offer parametric images with higher SNR compared to the indirect method. The aim of this study was to extend and evaluate the performance of a direct parametric reconstruction method using in-vivo dynamic PET MPI data for the purpose of quantifying MBF. Dynamic PET MPI studies were performed on two healthy pigs using a Siemens Biograph mMR scanner. List-mode PET data for each animal were acquired following a bolus injection of ~7-8 mCi of 18F-flurpiridaz, a myocardial perfusion agent. Fully-3D dynamic PET sinograms were obtained by sorting the coincidence events into 16 temporal frames covering ~5 min after radiotracer administration. Additionally, eight independent noise realizations of both scans - each containing 1/8th of the total number of events - were generated from the original list-mode data. Dynamic sinograms were then used to compute parametric maps using the conventional indirect method and the proposed direct method. For both methods, a one-tissue compartment model accounting for spillover from the left and right ventricle blood-pools was used to describe the kinetics of 18F-flurpiridaz. An image-derived arterial input function obtained from a TAC taken in the left ventricle cavity was used for tracer kinetic analysis. For the indirect method, frame-by-frame images were estimated using two fully-3D reconstruction techniques: the standard Ordered Subset Expectation Maximization (OSEM) reconstruction algorithm on one side, and the One-Step Late Maximum a Posteriori (OSL-MAP) algorithm on the other

  4. Impaired exercise-related myocardial uptake of technetium-99m-tetrofosmin in relation to coronary narrowing and diabetic state

    International Nuclear Information System (INIS)

    Sasao, Hisataka; Nakata, Tomoaki; Tsuchihashi, Kazufumi; Wakabayashi, Takeru; Nakahara, Norifumi; Doi, Atsushi; Hashimoto, Akiyoshi; Kobayashi, Hiroshi; Shimamoto, Kazuaki

    2001-01-01

    Despite the diagnostic efficacy of stress myocardial perfusion imaging, the correlation between the actual perfusion tracer activity and diseased state of a coronary artery has not been studied in detail. We estimated exercise-related perfusion augmentation in relation to disease states of a coronary artery in diabetic and non-diabetic patients by a newly developed quantitative technetium (Tc)-99m-tetrofosmin myocardial imaging technique. Tc-99m-tetrofosmin tomographic imaging with an exercise-rest protocol was performed in 26 stable coronary patients and in 8 age-matched controls. Percent increase (%IR) in myocardial count during symptom-limited submaximal exercise-stress was calculated in 16 non-infarcted polar map segments and in each coronary territory by a subtraction technique with corrections for physical decay and injected tracer doses, and the results were compared with those of angiographically quantified coronary diameter stenosis (%DS). Percent IR and peak heart rate during exercise showed a positive linear correlation both in coronary territories with significant stenosis (%DS≥75%) and in control or non-stenotic (%DS<75%) territories. The regression line in stenotic regions was, however, significantly (p<0.01) shifted downward compared to that in non-stenotic regions. Percent IR in stenotic regions showed a significant inverse correlation with %DS. Coronary stenosis of 75% or more was identified by a %IR cutoff value of 40% with 77% sensitivity, 70% specificity, and an accuracy of 72%. In coronary territories with a %DS of less than 75%, %IR in diabetic patients was significantly lower (46±15%) than that in non-diabetic patients (61±25%). Thus, blunted exercise-related augmentation of myocardial uptake of Tc-99m-tetrofosmin correlates with the severity of coronary narrowing and diabetic state. (author)

  5. Measurement of extracellular volume and transit time heterogeneity using contrast-enhanced myocardial perfusion MRI in patients after acute myocardial infarction.

    Science.gov (United States)

    Kunze, Karl P; Rischpler, Christoph; Hayes, Carmel; Ibrahim, Tareq; Laugwitz, Karl-Ludwig; Haase, Axel; Schwaiger, Markus; Nekolla, Stephan G

    2017-06-01

    To assess the ability of dynamic contrast-enhanced myocardial perfusion MRI to measure extracellular volume (ECV) and to investigate the possibility of estimating capillary transit time heterogeneity (CTH) in patients after myocardial infarction and successful revascularization. Twenty-four perfusion data sets were acquired on a 3 Tesla positron emission tomography (PET)/MRI scanner. Three perfusion models of different complexity were implemented in a hierarchical fashion with an Akaike information criterion being used to determine the number of fit parameters supported by the data. Results were compared sector-wise to ECV from an equilibrium T 1 mapping method (modified look-locker inversion recovery (MOLLI)). ECV derived from the perfusion analysis correlated well with equilibrium measurements (R² = 0.76). Estimation of CTH was supported in 16% of sectors (mostly remote). Inclusion of a nonzero CTH parameter usually led to lower estimates of first-pass extraction and slightly higher estimates of blood volume and flow. Estimation of the capillary permeability-surface area product was feasible in 81% of sectors. Transit time heterogeneity has a measurable effect on the kinetic analysis of myocardial perfusion MRI data, and Gd-DTPA extravasation in the myocardium is usually not flow-limited in infarct-related pathology. Measurement of myocardial ECV using perfusion imaging could provide a scan-time efficient alternative to methods based on T 1 mapping. Magn Reson Med 77:2320-2330, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  6. Tracer disposition kinetics in the determination of local cerebral blood flow by a venous equilibrium model, tube model, and distributed model

    International Nuclear Information System (INIS)

    Sawada, Y.; Sugiyama, Y.; Iga, T.; Hanano, M.

    1987-01-01

    Tracer distribution kinetics in the determination of local cerebral blood flow (LCBF) were examined by using three models, i.e., venous equilibrium, tube, and distributed models. The technique most commonly used for measuring LCBF is the tissue uptake method, which was first developed and applied by Kety. The measurement of LCBF with the 14 C-iodoantipyrine (IAP) method is calculated by using an equation derived by Kety based on the Fick's principle and a two-compartment model of blood-tissue exchange and tissue concentration at a single data point. The procedure, in which the tissue is to be in equilibrium with venous blood, will be referred to as the tissue equilibration model. In this article, effects of the concentration gradient of tracer along the length of the capillary (tube model) and the transverse heterogeneity in the capillary transit time (distributed model) on the determination of LCBF were theoretically analyzed for the tissue sampling method. Similarities and differences among these models are explored. The rank order of the LCBF calculated by using arterial blood concentration time courses and the tissue concentration of tracer based on each model were tube model (model II) less than distributed model (model III) less than venous equilibrium model (model I). Data on 14 C-IAP kinetics reported by Ohno et al. were employed. The LCBFs calculated based on model I were 45-260% larger than those in models II or III. To discriminate among three models, we propose to examine the effect of altering the venous infusion time of tracer on the apparent tissue-to-blood concentration ratio (lambda app). A range of the ratio of the predicted lambda app in models II or III to that in model I was from 0.6 to 1.3

  7. Weak-strong clustering transition in renewing compressible flows

    OpenAIRE

    Dhanagare, Ajinkya; Musacchio, Stefano; Vincenzi, Dario

    2014-01-01

    International audience; We investigate the statistical properties of Lagrangian tracers transported by a time-correlated compressible renewing flow. We show that the preferential sampling of the phase space performed by tracers yields significant differences between the Lagrangian statistics and its Eulerian counterpart. In particular, the effective compressibility experienced by tracers has a non-trivial dependence on the time correlation of the flow. We examine the consequence of this pheno...

  8. Myocardial Bridge

    Science.gov (United States)

    ... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

  9. Diagnosis of coronary stenosis using thallium-201 myocardial emission computed tomography

    International Nuclear Information System (INIS)

    Ito, Tsunaaki; Takeda, Hiroshi; Maeda, Hisato; Nakagawa, Tsuyoshi; Yamaguchi, Nobuo; Makino, Katsutoshi; Futagami, Yasuo; Konishi, Tokuji

    1985-01-01

    Thallium-201 myocardial emission computed tomography (ECT) was described with respect to methods of correcting ECT data and reconstructing the images, qualitative and quantitative diagnosis in the detection of coronary stenosis. Although 201 Tl myocardial ECT (using circumferential profile method combined with washout method) has relatively high diagnostic sensitivity, the correction of absorption is not satisfactory yet. Inside absorption coefficient is considered uniform by regarding the human body as oval shape. However, the chest, including the heart, lungs, vertebrae and thoracic wall, has four different absorption coefficients. If absorption can be corrected accurately, it will be possible to completely assess the myocardial blood flow by measuring the regional myocardial uptake of thallium-201. (Namekawa, K.)

  10. A comparative modeling study of a dual tracer experiment in a large lysimeter under atmospheric conditions

    Science.gov (United States)

    Stumpp, C.; Nützmann, G.; Maciejewski, S.; Maloszewski, P.

    2009-09-01

    SummaryIn this paper, five model approaches with different physical and mathematical concepts varying in their model complexity and requirements were applied to identify the transport processes in the unsaturated zone. The applicability of these model approaches were compared and evaluated investigating two tracer breakthrough curves (bromide, deuterium) in a cropped, free-draining lysimeter experiment under natural atmospheric boundary conditions. The data set consisted of time series of water balance, depth resolved water contents, pressure heads and resident concentrations measured during 800 days. The tracer transport parameters were determined using a simple stochastic (stream tube model), three lumped parameter (constant water content model, multi-flow dispersion model, variable flow dispersion model) and a transient model approach. All of them were able to fit the tracer breakthrough curves. The identified transport parameters of each model approach were compared. Despite the differing physical and mathematical concepts the resulting parameters (mean water contents, mean water flux, dispersivities) of the five model approaches were all in the same range. The results indicate that the flow processes are also describable assuming steady state conditions. Homogeneous matrix flow is dominant and a small pore volume with enhanced flow velocities near saturation was identified with variable saturation flow and transport approach. The multi-flow dispersion model also identified preferential flow and additionally suggested a third less mobile flow component. Due to high fitting accuracy and parameter similarity all model approaches indicated reliable results.

  11. Certification of flow measurement methods and calibration of flowmeters in oil and gas industry using radioactive tracers

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, L. E. E.; Kenup, H.O. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Nóbrega, Armi W.; Gonçalves, E.R.; Dualibi Filho, J.C.; Malheiro, R.L., E-mail: brandaos@ien.gov.br, E-mail: atomum@atomum.com.br [ATOMUM Serviços Tecnológicos Ltda, Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Oil and gas, mineral and water supply plants are the typical example of industrial facilities where they need accuracy in fluid flow measurement's procedures. In these installations, large quantities of materials are moving daily inside pipes, and one of the major problems of these industries is the safety of operations in transport of these materials. In order to monitor the transference processes many flowmeters are installed in the pipes to measure constantly the condition of the transported fluid. These flowmeters must be periodically calibrated, and one of the problems in this standardization is that these instruments need to be removed from the pipelines where they are operating and transported to the accredited laboratories to be calibrated. To remove a flowmeter from a pipe is not an easy operation, and in most of the cases, it is a very expensive operation, and in addition, any changes in the pipeline configuration can provoke leaks and when a leak occurs, it is impossible to operate the whole line and provokes accidents. Radiotracer technique is noninvasive fluid flow measure and using proper radiotracers is possible to measure organic, aqueous and gaseous flows without any disturbance in the normal operation of the pipeline. In this work, we present the ATOMUM{sub T}RACER, a software used to determine geometrical and technical procedures to calculate the Residence Time Curves using radiotracer techniques to accurately measure flow of fluids in pipelines with uncertainties around 0.7%. (author)

  12. Prediction of functional recovery after primary PCI using the estimate of myocardial salvage in gated SPECT early after acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Calabretta, Raffaella; Castello, Angelo; Linguanti, Flavia; Tutino, Francesca; Ciaccio, Alfonso; Sciagra, Roberto [University of Florence, Nuclear Medicine Unit, Department of Experimental and Clinical Biomedical Sciences ' ' Mario Serio' ' , Florence (Italy); Giglioli, Cristina [Careggi University Hospital, Cardiothoracovascular Department, Florence (Italy)

    2018-04-15

    Primary percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) aims to achieve myocardial salvage (MS). Because the reference method for measuring MS requires myocardial perfusion imaging (MPI) after tracer injection before PCI, alternative approaches have been proposed, but none has gained wide acceptance. Gated SPECT MPI can assess infarct size (IS), but can also show myocardial stunning. Thus, we compared functional and perfusion abnormalities early after AMI to estimate MS, and to predict left ventricular ejection fraction (LVEF) recovery at follow-up. We studied 120 patients with AMI. Gated SPECT MPI was performed early (before hospital discharge) and at 6 months after AMI to measure IS, MS and functional outcome. MS was defined as the difference between the number of segments with abnormal thickening (i.e. the stunned area or area at risk) and the number of segments with abnormal perfusion (i.e. the final IS), expressed as a percentage of the total number of segments in the AHA model. LVEF was calculated using quantitative gated SPECT. The area at risk was 40 ± 25%, IS was 17.3 ± 16% and MS was 22 ± 19%. Early LVEF was 46.6 ± 11.6% and late LVEF was 51.4 ± 11.6%, with 54 patients showing at least an increase in LVEF of more than 5 units. ROC analysis showed that MS was able to predict LVEF recovery with an area under the curve (AUC) of 0.79 (p < 0.0001), and using a cut off >23% detected LVEF recovery with 74% sensitivity and 71% specificity. Conversely, IS was associated with an AUC 0.53 (not significant). MS assessed by a single early gated SPECT MPI study can accurately predict LVEF evolution after primary PCI for AMI. (orig.)

  13. The usefulness of the nuclear cardiology in the cellular implant in patients with severe myocardial damage

    International Nuclear Information System (INIS)

    Omelas A, M.; Arguero S, R.; Garrido G, M.H.; Rodriguez C, A.; Careaga, G.; Castano G, R.; Nambo, M.J.; Pascual P, J.; Ortega R, A.; Gaxiola A, A.; Magana S, J.A.; Estrada A, H.; Equipo de Tecnicos en Medicina Nuclear

    2005-01-01

    The recent therapeutic advances as the cellular implant as well as those different protocols of image acquisition in the field of the Nuclear Cardiology its have allowed that the patient with severe myocardial damage and without some possibility of revascularization is benefited with these advances. Doubtless the Tl-201 par excellence has an important paper for standardize the more appropriate therapeutic behavior for the heart attack patient; reason by this investigation protocol was developed. The objective of the study was to identify the heart attack regions without viable tissue with SPECT in patient with important myocardial damage without some possibility of traditional revascularization; for the 'Stem cell' cellular implantation therapy. The methodology it was carried out by a study of myocardial perfusion in 10 patients with important myocardial damage previous cellular implants, with PICANUC/ SPECT methodology and using a software (Emory Tool Box) for the image processing validated by the University of Emory Atlanta GA; and using as tracer the Tl - 201 to identify the heart attack regions without presence of viable tissue with an analysis model of 17 segments standardized for the left ventricle; qualifying this way the myocardial perfusion in: 0 (normal), 1 (light), 2 (moderate), 3 (severe), 4 (absent) and x (bad technique). The conclusions were that the SPECT study with PICANUC methodology with Tl-201 is safe and effective for the precise localization for the cellular implantation via direct intra myocardial. (Author)

  14. Dynamics and mechanics of bed-load tracer particles

    Directory of Open Access Journals (Sweden)

    C. B. Phillips

    2014-12-01

    Full Text Available Understanding the mechanics of bed load at the flood scale is necessary to link hydrology to landscape evolution. Here we report on observations of the transport of coarse sediment tracer particles in a cobble-bedded alluvial river and a step-pool bedrock tributary, at the individual flood and multi-annual timescales. Tracer particle data for each survey are composed of measured displacement lengths for individual particles, and the number of tagged particles mobilized. For single floods we find that measured tracer particle displacement lengths are exponentially distributed; the number of mobile particles increases linearly with peak flood Shields stress, indicating partial bed load transport for all observed floods; and modal displacement distances scale linearly with excess shear velocity. These findings provide quantitative field support for a recently proposed modeling framework based on momentum conservation at the grain scale. Tracer displacement is weakly negatively correlated with particle size at the individual flood scale; however cumulative travel distance begins to show a stronger inverse relation to grain size when measured over many transport events. The observed spatial sorting of tracers approaches that of the river bed, and is consistent with size-selective deposition models and laboratory experiments. Tracer displacement data for the bedrock and alluvial channels collapse onto a single curve – despite more than an order of magnitude difference in channel slope – when variations of critical Shields stress and flow resistance between the two are accounted for. Results show how bed load dynamics may be predicted from a record of river stage, providing a direct link between climate and sediment transport.

  15. Using tracers to understand the hydrology of an abandoned underground coal mine

    International Nuclear Information System (INIS)

    Canty, G.A.; Everett, J.W.

    1998-01-01

    Flooded underground mines pose a difficult problem for remediation efforts requiring hydrologic information. Mine environments are hydraulically complicated due to sinuous travel paths and variable hydraulic gradients. For an acidic mine remediation project, conducted by the University of Oklahoma in conjunction with the Oklahoma Conservation Commission, a tracer study was undertaken to identify basic hydrologic properties of a flooded coal mine. The study was conducted to investigate the possibility of in-situ remediation of acidic mine water with the use of alkaline coal combustion by-products. Information on the rate of flow and ''connectiveness'' of injection wells with the discharge point was needed to develop a treatment strategy. Fluorescent dyes are not typically used in mine tracer studies because of the low pH values associated with certain mines and a tendency to adsorb ferric iron precipitates. However, Rhodamine WT was used in one tracer test because it can be detected at low concentrations. Due to poor recovery, a second tracer test was undertaken using a more conservative tracer-chloride. Each tracer produced similar travel time results. Findings from this study suggest that Rhodamine WT can be used under slightly acidic conditions, with mixed results. The more conservative tracer provided somewhat better results, but recovery was still poor. Use of these tracers has provided some valuable information with regard to mine hydrology, but additional questions have been raised

  16. Noninvasive assessment of canine myocardial oxidative metabolism with carbon-11 acetate and positron emission tomography

    International Nuclear Information System (INIS)

    Brown, M.A.; Myears, D.W.; Bergmann, S.R.

    1988-01-01

    Noninvasive quantification of regional myocardial metabolism would be highly desirable to evaluate pathogenetic mechanisms of heart disease and their response to therapy. It was previously demonstrated that the metabolism of radiolabeled acetate, a readily utilized myocardial substrate predominantly metabolized to carbon dioxide (CO2) by way of the tricarboxylic acid cycle, provides a good index of oxidative metabolism in isolated perfused rabbit hearts because of tight coupling between the tricarboxylic acid cycle and oxidative phosphorylation. In the present study, in a prelude to human studies, the relation between myocardial clearance of carbon-11 (11C)-labeled acetate and myocardial oxygen consumption was characterized in eight intact dogs using positron emission tomography. Anesthetized dogs were studied during baseline conditions and again during either high or low work states induced pharmacologically. High myocardial extraction and rapid blood clearance of tracer yielded myocardial images of excellent quality. The turnover (clearance) of 11C radioactivity from the myocardium was biexponential with the mean half-time of the dominant rapid phase averaging 5.4 +/- 2.2, 2.8 +/- 1.3 and 11.1 +/- 1.3 min in control, high and low work load studies, respectively. No significant difference was found between the rate of clearance of 11C radioactivity from the myocardium measured noninvasively with positron emission tomography and the myocardial efflux of 11CO2 measured directly from the coronary sinus. The rate of clearance of the 11C radioactivity from the heart correlated closely with myocardial oxygen consumption (r = 0.90, p less than 0.001) as well as with the rate-pressure product (r = 0.95, p less than 0.001). Hence, the rate of oxidation of 11C-acetate can be determined noninvasively with positron emission tomography, providing a quantitative index of oxidative metabolism under diverse conditions

  17. Story of rubidium-82 and advantages for myocardial perfusion PET imaging

    Directory of Open Access Journals (Sweden)

    Jean-Francois eChatal

    2015-09-01

    Full Text Available Rubidium-82 has a long story, starting in 1954. After preclinical studies in dogs showing that myocardial uptake of this radionuclide was directly proportional to myocardial blood flow, clinical studies were performed in the 80s leading to an approval in the USA in 1989. From that time thousands of patients have been tested and their results have been reported in 3 meta-analyses. Pooled patient-based sensitivity and specificity were respectively 0.91 and 0.90. By comparison with 99mTc-SPECT, 82Rb-PET had a much better diagnostic accuracy, especially in obese patients with BMI (Body Mass Index ≥30 kg/m2 (85% versus 67% with SPECT and in women with large breasts. A great advantage of 82Rb-PET is its capacity to accurately quantify myocardial blood flow. Quite importantly it has been recently shown that coronary flow reserve is associated with adverse cardiovascular events independently of luminal angiographic severity. Moreover coronary flow reserve is a functional parameter particularly useful in the estimate of microvascular dysfunction such as in diabetes mellitus. Due to the very short half-life of rubidium-82, the effective dose calculated for a rest/stress test is roughly equivalent to the annual natural exposure and even less when stress-only is performed with a low activity compatible with a good image quality with the last generation 3D PET scanners.There is still some debate on the relative advantages of 82Rb-PET with regard to 99mTc-SPECT. For the last ten years, great technological advances substantially improved performances of SPECT with its accuracy getting closer to this of 82Rb/PET. Currently the main advantages of PET are its capacity to accurately quantify myocardial blood flow and to deliver a low radiation exposure.

  18. 18F-labelled annexin V: a PET tracer for apoptosis imaging

    International Nuclear Information System (INIS)

    Murakami, Yoshihiro; Tatsumi, Mitsuyoshi; Ichise, Rikiya; Nishimura, Shintaro; Takamatsu, Hiroyuki; Noda, Akihiro; Taki, Junichi; Tait, Jonathan F.

    2004-01-01

    Annexin V can be used to detect apoptotic cells in vitro and in vivo, based on its ability to identify extracellular phosphatidylserine, which arises during apoptosis. In the present study, we examined the synthesis of fluorine-18 labelled annexin V as a positron emission tomography tracer for apoptosis imaging. The distribution of [ 18 F]annexin V and technetium-99m labelled annexin V, a well-characterised SPET tracer for apoptosis imaging, was compared. [ 18 F]annexin V was synthesised using N-succinimidyl 4-[ 18 F]fluorobenzoate as an 18 F labelling reagent. Synthesised and purified [ 18 F]annexin V was confirmed by SDS-PAGE. In an ex vivo imaging experiment, [ 18 F]annexin V was intravenously injected into rats 24 h after the induction of myocardial ischaemia, and accumulation in the left ventricle was examined. [ 18 F]annexin V accumulated in the infarct area of the left ventricle, where apoptotic cells were observed. In separate experiments, [ 18 F]annexin V or [ 99m Tc]annexin V was intravenously injected into ischaemic or normal animals, and the distribution of the tracers was compared. In ischaemic animals, accumulation of [ 18 F]annexin V and [ 99m Tc]annexin V in the infarct area was about threefold higher than in the non-infarct area. Furthermore, the ratio of accumulation in the normal heart to the blood radioactivity was not significantly different between the tracers. In normal animals, however, the uptake of [ 18 F]annexin V in the liver, spleen and kidney was much lower than that of [ 99m Tc]annexin V. The low uptake of [ 18 F]annexin V in these organs might represent an advantage over [ 99m Tc]annexin V. (orig.)

  19. Interface flow process audit: using the patient's career as a tracer of quality of care and of system organisation

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Unger

    2004-05-01

    Full Text Available Objectives: This case study aims to demonstrate the method's feasibility and capacity to improve quality of care. Several drawbacks attached to tracer condition and selected procedure audits oblige clinicians to rely on external evaluators. Interface flow process audit is an alternative method, which also favours integration of health care across institutions divide. Methods: An action research study was carried out to test the feasibility of interface flow process audit and its impact on quality improvement. An anonymous questionnaire was carried out to assess the participants' perception of the process. Results: In this study, interface flow process audit brought together general practitioners and hospital doctors to analyse the co-ordination of their activities across the primary-secondary interface. Human factors and organisational characteristics had a clear influence on implementation of the solutions. In general, the participants confirmed that the interface flow process audit helped them to analyse the quality of case management both at primary and secondary care level. Conclusions: The interface flow process audit appears a useful method for regular in-service self-evaluation. Its practice enabled to address a wide scope of clinical, managerial and economical problems. Bridging the primary-secondary care gap, interface flow process audit's focus on the patient's career combined with the broad scope of problems that can be analysed are particularly powerful features. The methodology would benefit from an evaluation of its practice on larger scale.

  20. Using environmental tracers in modeling flow in a complex shallow aquifer system

    DEFF Research Database (Denmark)

    Troldborg, Lars; Jensen, Karsten Høgh; Engesgaard, Peter Knudegaard

    2008-01-01

    shapes and sizes without being similar to the assumed age distributions used in the analytical approach. The shape of age distribution to some extent depends on sampling size and on whether the system is modeled in a transient or in a steady state, but shape and size were largely driven......Using environmental tracers in groundwater dating partly relies on the assumption that groundwater age distribution can be described analytically. To investigate the applicability of age dating in complex multiaquifer systems, a methodology for simulating well specific groundwater age distribution...... was developed. Using a groundwater model and particle tracking we modeled age distributions at screen locations. By enveloping modeled age distributions and estimated recharge concentrations, environmental tracer breakthroughs were simulated for specific screens. Simulated age distributions are of irregular...