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Sample records for fluid perfusion rate

  1. Effects of Initial Seeding Density and Fluid Perfusion Rate on Formation of Tissue-Engineered Bone

    OpenAIRE

    GRAYSON, WARREN L.; BHUMIRATANA, SARINDR; CANNIZZARO, CHRISTOPHER; CHAO, P.-H. GRACE; LENNON, DONALD P.; CAPLAN, ARNOLD I.; VUNJAK-NOVAKOVIC, GORDANA

    2008-01-01

    We describe a novel bioreactor system for tissue engineering of bone that enables cultivation of up to six tissue constructs simultaneously, with direct perfusion and imaging capability. The bioreactor was used to investigate the relative effects of initial seeding density and medium perfusion rate on the growth and osteogenic differentiation patterns of bone marrow–derived human mesenchymal stem cells (hMSCs) cultured on three-dimensional scaffolds. Fully decellularized bovine trabecular bon...

  2. Effects of Stirring and Fluid Perfusion on the In Vitro Degradation of Calcium Phosphate Cement/PLGA Composites

    NARCIS (Netherlands)

    An, J.; Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Jansen, J.A.

    2015-01-01

    In vitro degradation rates of calcium phosphate bioceramics are investigated using a large variation of soaking protocols that do not all match the dynamic conditions of the perfused physiological environment. Therefore, we studied the effect of stirring and fluid perfusion on the in vitro

  3. Effects of Constant Flow vs. Constant Pressure Perfusion on Fluid Filtration in Severe Hypothermic Isolated Blood-Perfused Rat Lungs.

    Science.gov (United States)

    Halsøy, Kathrine; Kondratiev, Timofey; Tveita, Torkjel; Bjertnaes, Lars J

    2016-01-01

    Victims of severe accidental hypothermia are prone to fluid extravasation but rarely develop lung edema. We hypothesize that combined hypothermia-induced increase in pulmonary vascular resistance (PVR) and a concomitant fall in cardiac output protect the lungs against edema development. Our aim was to explore in hypothermic-isolated blood-perfused rat lungs whether perfusion at constant pressure influences fluid filtration differently from perfusion at constant flow. Isolated blood-perfused rat lungs were hanging freely in a weight transducer for measuring weight changes (ΔW). Fluid filtration coefficient (Kfc), was determined by transiently elevating left atrial pressure (Pla) by 5.8 mmHg two times each during normothermia (37°C) and during hypothermia (15°C). The lung preparations were randomized to two groups. One group was perfused with constant flow (Constant flow group) and the other group with constant pulmonary artery pressure (Constant PPA group). Microvascular pressure (Pmv) was determined before and during elevation of Pla (ΔPmv) by means of the double occlusion technique. Kfc was calculated with the formula Kfc = ΔW/ΔPmv/min. All Kfc values were normalized to predicted lung weight (P LW ), which was based on body weight (BW) according to the formula: P LW  = 0.0053 BW - 0.48 and presented as Kfc PLW in mg/min/mmHg/g. At cessation, bronchoalveolar lavage (BAL) fluid/perfusate protein concentration (B/P) ratio was determined photometrically. Data were analyzed with parametric or non-parametric tests as appropriate. p  Kfc PLW and B/P ratio increased significantly by more than 10-fold during hypothermia concerted by visible signs of edema in the trachea. Hemoglobin and hematocrit increased within the Constant flow group and between the groups at cessation of the experiments. In hypothermic rat lungs perfused at constant flow, fluid filtration coefficient per gram P LW and B/P ratio increased more than 10-fold concerted by increased

  4. Achieving low anastomotic leak rates utilizing clinical perfusion assessment.

    Science.gov (United States)

    Kream, Jacob; Ludwig, Kirk A; Ridolfi, Timothy J; Peterson, Carrie Y

    2016-10-01

    Anastomotic leak after colorectal resection increases morbidity, mortality, and in the setting of cancer, increases recurrences rates and reduces survival odds. Recent reports suggest that fluorescence evaluation of perfusion after colorectal anastomosis creation is associated with low anastomotic leak rates (1.4%). The purpose of this work was to evaluate whether a similar low anastomotic leak rate after left-sided colorectal resections could be achieved using standard assessment of blood flow to the bowel ends. We performed a retrospective chart review at an academic tertiary referral center, evaluating 317 consecutive patients who underwent a pelvic anastomosis after sigmoid colectomy, left colectomy, or low anterior resection. All operations were performed by a single surgeon from March 2008 to January 2015 with only standard clinical measures used to assess perfusion to the bowel ends. The primary outcome measure was the anastomotic leak rate as diagnosed by clinical symptoms, exam, or routine imaging. The average patient age was 59.7 years with an average body mass index of 28.8 kg/m(2). Rectal cancer (128, 40.4%) was the most common indication for operation while hypertension (134, 42.3%) was the most common comorbidity. In total, 177 operations were laparoscopic (55.8%), 13 were reoperative resections (4.1%), and 108 were protected with a loop ileostomy (34.1%). Preoperative chemotherapy was administered to 25 patients (7.9%) while preoperative chemo/radiation was administered to 64 patients (20.2%). The anastomotic leak rate was 1.6% (5/317). Our data suggests that standard, careful evaluation of adequate blood flow via inspection and confirmation of pulsatile blood flow to the bowel ends and meticulous construction of the colorectal or coloanal anastomoses can result in very low leak rates, similar to the rate reported when intraoperative imaging is used to assess perfusion. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Fluid extravasation of the articular capsule as a complication of temporomandibular joint pumping and perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Kenichi; Watahiki, Ryuichirou; Tamura, Hidetoshi; Ogura, Motoi; Shibuya, Masayuki [Kameda General Hospital, Kamogawa, Chiba (Japan)

    2002-11-01

    This report is a retrospective study of fluid extravasation as a complication of temporomandibular joint pumping and perfusion. Contrast-enhanced 3D-CT of the upper joint compartment was performed for presurgical diagnosis before temporomandibular joint arthroscopic surgery in our hospital from 1996 to 2000. From these cases, 43 joints and 38 patients were selected because they had not improved under conservative treatment during the previous six months. Fluid extravasation of the articular capsule was recognized in 9 joints (20.9%) in 9 patients, 3 males and 6 females. Two of the nine patients had undergone arthroscopic observation before surgery. This test had revealed only thin articular capsule, not a perforation, in any of these cases. The data indicate only extremely tiny perforations or infiltration leakage due to the fluid pressure in the upper joint compartment during pumping or perfusion. Oral and maxillofacial surgeons should be aware of this complication. (author)

  6. Effects of fluids on microvascular perfusion in patients with severe sepsis.

    Science.gov (United States)

    Ospina-Tascon, Gustavo; Neves, Ana Paula; Occhipinti, Giovanna; Donadello, Katia; Büchele, Gustavo; Simion, Davide; Chierego, Maria-Luisa; Silva, Tatiana Oliveira; Fonseca, Adriana; Vincent, Jean-Louis; De Backer, Daniel

    2010-06-01

    To evaluate the effects of fluid administration on microcirculatory alterations in sepsis. With a Sidestream Dark Field device, we evaluated the effects of fluids on the sublingual microcirculation in 60 patients with severe sepsis. These patients were investigated either within 24 h (early, n = 37) or more than 48 h (late, n = 23) after a diagnosis of severe sepsis. Hemodynamic and microcirculatory measurements were obtained before and 30 min after administration of 1,000 ml Ringer's lactate (n = 29) or 400 ml 4% albumin (n = 31) solutions. Fluid administration increased perfused small vessel density from 3.5 (2.9-4.3) to 4.4 (3.7-4.9) n/mm (p density from 5.3 (4.4-5.9) to 5.6 (4.8-6.3) n/mm (p fluids were not related to changes in cardiac index (R(2) = 0.05, p = ns) or mean arterial pressure (R(2) = 0.04, p = ns). In this non-randomized trial, fluid administration improved microvascular perfusion in the early but not late phase of sepsis. This effect is independent of global hemodynamic effects and of the type of solution.

  7. Bernoulli's Principle Applied to Brain Fluids: Intracranial Pressure Does Not Drive Cerebral Perfusion or CSF Flow.

    Science.gov (United States)

    Schmidt, Eric; Ros, Maxime; Moyse, Emmanuel; Lorthois, Sylvie; Swider, Pascal

    2016-01-01

    In line with the first law of thermodynamics, Bernoulli's principle states that the total energy in a fluid is the same at all points. We applied Bernoulli's principle to understand the relationship between intracranial pressure (ICP) and intracranial fluids. We analyzed simple fluid physics along a tube to describe the interplay between pressure and velocity. Bernoulli's equation demonstrates that a fluid does not flow along a gradient of pressure or velocity; a fluid flows along a gradient of energy from a high-energy region to a low-energy region. A fluid can even flow against a pressure gradient or a velocity gradient. Pressure and velocity represent part of the total energy. Cerebral blood perfusion is not driven by pressure but by energy: the blood flows from high-energy to lower-energy regions. Hydrocephalus is related to increased cerebrospinal fluid (CSF) resistance (i.e., energy transfer) at various points. Identification of the energy transfer within the CSF circuit is important in understanding and treating CSF-related disorders. Bernoulli's principle is not an abstract concept far from clinical practice. We should be aware that pressure is easy to measure, but it does not induce resumption of fluid flow. Even at the bedside, energy is the key to understanding ICP and fluid dynamics.

  8. Fluid Power, Rate Training Manual.

    Science.gov (United States)

    Bureau of Naval Personnel, Washington, DC.

    Fundamentals of hydraulics and pneumatics are presented in this manual, prepared for regular navy and naval reserve personnel who are seeking advancement to Petty Officer Third Class. The history of applications of compressed fluids is described in connection with physical principles. Selection of types of liquids and gases is discussed with a…

  9. The effect of perfusion and irrigation flow rate variations on NaCl efflux from the isolated, perfused head of the marine teleost, Myoxocephalus octodecimspinosus

    International Nuclear Information System (INIS)

    Claiborne, J.B.; Evans, D.H.

    1981-01-01

    In vivo branchial blood pressure and unidirectional efflux values for NaCl were determined in the marine teleost, Myoxocephalus octodecimspinosus. Utilizing an isolated, perfused head preparation, perfused at in vivo pressure levels, NaCl efflux was measured and compared to in vivo values. The effect of variations in perfusion or irrigation rates on the ion efflux across the gills of the isolated head was also studied. The efflux of 22 Na from the isolated, perfused head was found to be similar to in vivo values and dependent on perfusion flow and pressure. In vitro 36 Cl efflux was lower than the efflux from intact animals and was determined to be flow/pressure independent. Irrigation rate changes at all rates tested did not affect the unidirectional efflux of either ion. (Auth.)

  10. Effect of perfusion and irrigation flow rate variations on NaCl efflux from the isolated, perfused head of the marine teleost, Myoxocephalus octodecimspinosus

    Energy Technology Data Exchange (ETDEWEB)

    Claiborne, J.B. (Miami Univ., Coral Gables, FL (USA)); Evans, D.H. (Mt. Desert Island Biological Laboratory, Salsbury Cove, ME, USA)

    1981-06-01

    In vivo branchial blood pressure and unidirectional efflux values for NaCl were determined in the marine teleost, Myoxocephalus octodecimspinosus. Utilizing an isolated, perfused head preparation, perfused at in vivo pressure levels, NaCl efflux was measured and compared to in vivo values. The effect of variations in perfusion or irrigation rates on the ion efflux across the gills of the isolated head was also studied. The efflux of /sup 22/Na from the isolated, perfused head was found to be similar to in vivo values and dependent on perfusion flow and pressure. In vitro /sup 36/Cl efflux was lower than the efflux from intact animals and was determined to be flow/pressure independent. Irrigation rate changes at all rates tested did not affect the unidirectional efflux of either ion.

  11. Parametric investigation of heating due to magnetic fluid hyperthermia in a tumor with blood perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Liangruksa, Monrudee [Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Ganguly, Ranjan [Department of Power Engineering, Jadavpur University, Kolkata 700098 (India); Puri, Ishwar K., E-mail: ikpuri@vt.ed [Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States)

    2011-03-15

    Magnetic fluid hyperthermia (MFH) is a cancer treatment that can selectively elevate the tumor temperature without significantly damaging the surrounding healthy tissue. Optimal MFH design requires a fundamental parametric investigation of the heating of soft materials by magnetic fluids. We model the problem of a spherical tumor and its surrounding healthy tissue that are heated by exciting a homogeneous dispersion of magnetic nanoparticles infused only into the tumor with an external AC magnetic field. The key dimensionless parameters influencing thermotherapy are the Peclet, Fourier, and Joule numbers. Analytical solutions for transient and steady hyperthermia provide correlations between these parameters and the portions of tumor and healthy tissue that are subjected to a threshold temperature beyond which they are damaged. Increasing the ratio of the Fourier and Joule numbers also increases the tumor temperature, but doing so can damage the healthy tissue. Higher magnetic heating is required for larger Peclet numbers due to the larger convection heat loss that occurs through blood perfusion. A comparison of the model predictions with previous experimental data for MFH applied to rabbit tumors shows good agreement. The optimal MFH conditions are identified based on two indices, the fraction I{sub T} of the tumor volume in which the local temperature is above a threshold temperature and the ratio I{sub N} of the damaged normal tissue volume to the tumor tissue volume that also lies above it. The spatial variation in the nanoparticle concentration is also considered. A Gaussian distribution provides efficacy while minimizing the possibility of generating a tumor hot spot. Varying the thermal properties of tumor and normal tissue alters I{sub T}and I{sub N} but the nature of the temperature distribution remains unchanged. - Research highlights: > Analytical model of magnetic fluid hyperthermia of tumor tissue perfused with magnetic nanoparticles that is surrounded

  12. Parametric investigation of heating due to magnetic fluid hyperthermia in a tumor with blood perfusion

    International Nuclear Information System (INIS)

    Liangruksa, Monrudee; Ganguly, Ranjan; Puri, Ishwar K.

    2011-01-01

    Magnetic fluid hyperthermia (MFH) is a cancer treatment that can selectively elevate the tumor temperature without significantly damaging the surrounding healthy tissue. Optimal MFH design requires a fundamental parametric investigation of the heating of soft materials by magnetic fluids. We model the problem of a spherical tumor and its surrounding healthy tissue that are heated by exciting a homogeneous dispersion of magnetic nanoparticles infused only into the tumor with an external AC magnetic field. The key dimensionless parameters influencing thermotherapy are the Peclet, Fourier, and Joule numbers. Analytical solutions for transient and steady hyperthermia provide correlations between these parameters and the portions of tumor and healthy tissue that are subjected to a threshold temperature beyond which they are damaged. Increasing the ratio of the Fourier and Joule numbers also increases the tumor temperature, but doing so can damage the healthy tissue. Higher magnetic heating is required for larger Peclet numbers due to the larger convection heat loss that occurs through blood perfusion. A comparison of the model predictions with previous experimental data for MFH applied to rabbit tumors shows good agreement. The optimal MFH conditions are identified based on two indices, the fraction I T of the tumor volume in which the local temperature is above a threshold temperature and the ratio I N of the damaged normal tissue volume to the tumor tissue volume that also lies above it. The spatial variation in the nanoparticle concentration is also considered. A Gaussian distribution provides efficacy while minimizing the possibility of generating a tumor hot spot. Varying the thermal properties of tumor and normal tissue alters I T and I N but the nature of the temperature distribution remains unchanged. - Research Highlights: →Analytical model of magnetic fluid hyperthermia of tumor tissue perfused with magnetic nanoparticles that is surrounded by healthy tissue

  13. Proteomic characterization of the interstitial fluid perfusing the breast tumor microenvironment

    DEFF Research Database (Denmark)

    Celis, Julio E; Gromov, Pavel; Cabezón, Teresa

    2004-01-01

    of biomarkers, the tumor interstitial fluid (TIF) that perfuses the breast tumor microenvironment. We collected TIFs from small pieces of freshly dissected invasive breast carcinomas and analyzed them by two-dimensional polyacrylamide gel electrophoresis in combination with matrix-assisted laser desorption....../ionization time-of-flight mass spectrometry, Western immunoblotting, as well as by cytokine-specific antibody arrays. This approach provided for the first time a snapshot of the protein components of the TIF, which we show consists of more than one thousand proteins--either secreted, shed by membrane vesicles...... synthesis, energy metabolism, oxidative stress, the actin cytoskeleton assembly, protein folding, and transport. As expected, the TIF contained several classical serum proteins. Considering that the protein composition of the TIF reflects the physiological and pathological state of the tissue, it should...

  14. Computational fluid dynamics modeling of momentum transport in rotating wall perfused bioreactor for cartilage tissue engineering.

    Science.gov (United States)

    Cinbiz, Mahmut N; Tığli, R Seda; Beşkardeş, Işil Gerçek; Gümüşderelioğlu, Menemşe; Colak, Uner

    2010-11-01

    In this study, computational fluid dynamics (CFD) analysis of a rotating-wall perfused-vessel (RWPV) bioreactor is performed to characterize the complex hydrodynamic environment for the simulation of cartilage development in RWPV bioreactor in the presence of tissue-engineered cartilage constructs, i.e., cell-chitosan scaffolds. Shear stress exerted on chitosan scaffolds in bioreactor was calculated for different rotational velocities in the range of 33-38 rpm. According to the calculations, the lateral and lower surfaces were exposed to 0.07926-0.11069 dyne/cm(2) and 0.05974-0.08345 dyne/cm(2), respectively, while upper surfaces of constructs were exposed to 0.09196-0.12847 dyne/cm(2). Results validate adequate hydrodynamic environment for scaffolds in RWPV bioreactor for cartilage tissue development which concludes the suitability of operational conditions of RWPV bioreactor. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Relationship between dynamic infrared thermal images and blood perfusion rate of the tongue in anaemia patients

    Science.gov (United States)

    Xie, Haiwei; Zhang, Yan

    2018-03-01

    The relationship between dynamic infrared (IR) thermal images and blood perfusion rate of the tongues of anaemia patients was investigated. Blood perfusion rates at multiple locations on the tongues of 62 anaemia patients and 70 control subjects were measured. For both groups of subjects, dynamic IR thermal images were also recorded within 16 s after the mouth opened. The results showed that the blood perfusion rates at different sites (apex, middle, left side and right side) on the tongues in anaemia patients (3.49, 3.71, 3.85 and 3.77 kg/s m-3) were significantly lower than those at the corresponding sites in control subjects (4.45, 4.66, 4.81 and 4.70 kg/s m-3). After the mouth opened, the tongue temperature decreased more rapidly in anaemia patients than in control subjects. To analyse the heat transfer mechanism, a transient heat transfer model of the tongue was developed. The tongue temperatures in anaemia patients and control subjects were calculated using this model and compared to the tongue temperatures measured by the IR thermal imager. The relationship between the tongue surface temperature and the tongue blood perfusion rate was analysed. The simulation results indicated that the low blood perfusion rate and the correlated changes in anaemia patients can cause faster temperature decreases of the tongue surface.

  16. Low predictive value of positive transplant perfusion fluid cultures for diagnosing postoperative infections in kidney and kidney-pancreas transplantation.

    LENUS (Irish Health Repository)

    Cotter, Meaghan P

    2012-12-01

    Infection following transplantation is a cause of morbidity and mortality. Perfusion fluid (PF) used to preserve organs between recovery and transplantation represents a medium suitable for the growth of microbes. We evaluated the relevance of positive growth from PF sampled before the implantation of kidney or kidney-pancreas (KP) allografts.

  17. Optimum solar collector fluid flow rates

    DEFF Research Database (Denmark)

    Furbo, Simon; Shah, Louise Jivan

    1996-01-01

    Experiments showed that by means of a standard electronically controlled pump, type UPE 2000 from Grundfos it is possible to control the flow rate in a solar collector loop in such a way that the flow rate is strongly influenced by the temperature of the solar collector fluid passing the pump....... The flow rate is increasing for increasing temperature.The flow rate at the high temperature level is typically 70 % greater than the flow rate at the low temperature level.Further, the energy consumption for the electronically controlled pump in a solar heating system will be somewhat smaller than...... the energy consumption of a normal ciculation pump in the solar heating system.Calculations showed that the highest thermal performances for small SDHW systems based on mantle tanks with constant volume flow rates in the solar collector loops are achieved if the flow rate is situated in the interval from 0...

  18. Variation in heart rate influences the assessment of transient ischemic dilation in myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Leslie, William D; Levin, Daniel P; Demeter, Sandor J

    2007-01-01

    Transient arrhythmias can affect transient ischemic dilation (TID) ratios. This study was initiated to evaluate the frequency and effect of normal heart rate change on TID measures in routine clinical practice. Consecutive patients undergoing stress/rest sestamibi gated myocardial perfusion scintigraphy were studied (N = 407). Heart rate at the time of stress and rest imaging were recorded. TID ratios were analyzed in relation to absolute change in heart rate (stress minus rest) for subjects with normal perfusion and systolic function (Group 1, N = 169) and those with abnormalities in perfusion and/or function (Group 2, N = 238). In Group 1, mean TID ratio was inversely correlated with the change in heart rate (r = -0.47, P < 0.0001). For every increase of 10 BPM in heart rate change, the TID ratio decreased by approximately 0.06 (95% confidence interval 0.04–0.07). In Group 2, multiple linear regression demonstrated that the change in heart rate (beta = -0.25, P < 0.0001) and the summed difference score (beta = 0.36, P < 0.0001) were independent predictors of the TID ratio. Normal variation in heart rate between the stress and rest components of myocardial perfusion scans is common and can influence TID ratios in patients with normal and abnormal cardiac scans

  19. Early effects of combretastatin-A4 disodium phosphate on tumor perfusion and interstitial fluid pressure

    DEFF Research Database (Denmark)

    Ley, C.D.; Horsman, Michael Robert; Kristjansen, P.E.G.

    2007-01-01

    /kg CA4DP by intraperitoneal injection. Tumor perfusion was recorded by laser Doppler flowmetry at separate time points, and IFP was recorded continuously by the wick-in-needle method. In this study, we found that CA4DP treatment resulted in a rapid reduction in tumor perfusion, followed by a decrease...

  20. Predictors of abnormal heart rate response to dipyridamole in patients undergoing myocardial perfusion SPECT

    International Nuclear Information System (INIS)

    De Souza Leao Lima, R.; Machado, L.; Azevedo, A.B.; De Lorenzo, A.

    2011-01-01

    The objective of this study was to identify predictors of abnormal HR response to dipyridamole (DIP) in patients undergoing myocardial perfusion SPECT (MPS). Patients with a reduced heart rate (HR) response to DIP have higher cardiac mortality, but the mechanism is unknown. We studied 432 patients who underwent dual-isotope gated MPS. DIP (0.56 mg/kg) was infused over 4 min, and Tc-99m tetrofosmin was injected 3 min after the end of the infusion. MPS was semiquantitatively interpreted. Left ventricular ejection fraction (LVEF) and volumes were automatically calculated. The population was categorized into quartiles according to HR ratio, and characteristics in each quartile were compared. Logistic regression analysis was performed to identify predictors of abnormal HR response, using the lowest quartile as the independent variable. Patients with abnormal HR response were more frequently without chest pain, with a history of chronic renal failure and taking digoxin. Baseline HR was higher and had fewer symptoms during stress. The stress and rest perfusion defects were greater, but reversibility was not; in addition, LVEF was lower. Multivariable logistic regression analysis demonstrated that the independent predictors of abnormal HR response were baseline HR and low LVEF. LV dysfunction is an independent predictor of abnormal HR response to DIP, and the association between low LVEF and low HR ratio may explain the link between abnormal HR ratio and increased mortality. (author)

  1. Glucose phosphorylation is not rate limiting for accumulation of glycogen from glucose in perfused livers from fasted rats

    International Nuclear Information System (INIS)

    Youn, J.H.; Ader, M.; Bergman, R.N.

    1989-01-01

    Incorporation of Glc and Fru into glycogen was measured in perfused livers from 24-h fasted rats using [6-3H]Glc and [U-14C]Fru. For the initial 20 min, livers were perfused with low Glc (2 mM) to deplete hepatic glycogen and were perfused for the following 30 min with various combinations of Glc and Fru. With constant Fru (2 mM), increasing perfusate Glc increased the relative contribution of Glc carbons to glycogen (7.2 +/- 0.4, 34.9 +/- 2.8, and 59.1 +/- 2.7% at 2, 10, and 20 mM Glc, respectively; n = 5 for each). During perfusion with substrate levels seen during refeeding (10 mM Glc, 1.8 mumol/g/min gluconeogenic flux from 2 mM Fru), Fru provided 54.7 +/- 2.7% of the carbons for glycogen, while Glc provided only 34.9 +/- 2.8%, consistent with in vivo estimations. However, the estimated rate of Glc phosphorylation was at least 1.10 +/- 0.11 mumol/g/min, which exceeded by at least 4-fold the glycogen accumulation rate (0.28 +/- 0.04 mumol of glucose/g/min). The total rate of glucose 6-phosphate supply via Glc phosphorylation and gluconeogenesis (2.9 mumol/g/min) exceeded reported in vivo rates of glycogen accumulation during refeeding. Thus, in perfused livers of 24-h fasted rats there is an apparent redundancy in glucose 6-phosphate supply. These results suggest that the rate-limiting step for hepatic glycogen accumulation during refeeding is located between glucose 6-phosphate and glycogen, rather than at the step of Glc phosphorylation or in the gluconeogenic pathway

  2. Study of magnetorheological fluids at high shear rates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaojie; Gordaninejad, Faramarz [University of Nevada, Department of Mechanical Engineering, Reno, NV (United States)

    2006-08-15

    The tunable rheological properties of magnetorheological (MR) materials at high shear rates are studied using a piston-driven flow-mode-type rheometer. The proposed method provides measurement of the apparent viscosity and yield stress of MR fluids for a shear rate range of 50 to 40,000 s{sup -1}. The rheological properties of a commercial MR fluid, as well as a newly developed MR polymeric gel, and a ferrofluid-based MR fluid are investigated. The results for apparent viscosity and dynamic and static shear stresses under different applied magnetic fields are reported. (orig.)

  3. Use of atropine in patients with submaximal heart rate during exercise myocardial perfusion SPECT.

    Science.gov (United States)

    De Lorenzo, Andrea; Foerster, James; Sciammarella, Maria G; Suey, Cathy; Hayes, Sean W; Friedman, John D; Berman, Daniel S

    2003-01-01

    Failure to reach 85% of maximal predicted heart rate (MPHR) during exercise may render a myocardial perfusion single photon emission computed tomography (MPS) study nondiagnostic for ischemia detection. Although commonly used to increase heart rate (HR) during dobutamine stress, the administration of atropine for patients failing to achieve 85% of MPHR during exercise performed for MPS is still infrequent. Patients undergoing dual-isotope MPS were considered candidates for the study when, during exercise treadmill testing, they had less than 85% of MPHR and were unable to continue because of fatigue, without an ischemic response. Forty-seven patients (aged 65.3 +/- 12.5 years, 78.7% men) received atropine (0.6-1.2 mg). Maximal HR achieved before and after atropine was 118.0 +/- 14.8 beats/min (76.3% +/- 6.2% of MPHR) and 146.4 +/- 12.6 beats/min (94.4% +/- 8.1% of MPHR), respectively (P < .001). Of patients, 44 (93.6%) reached at least 85% of MPHR after atropine and had diagnostic MPS studies. After atropine, arrhythmias occurred in 14 patients (29.8%) and other minor side effects in 1 (2.1%). Atropine allows patients initially failing to achieve 85% of MPHR during exercise to increase HR and have a diagnostic MPS study, without major complications. It may provide an alternative to pharmacologic stress for patients with a blunted HR response to exercise.

  4. Fluid intake rates in ants correlate with their feeding habits.

    Science.gov (United States)

    Paul, J; Roces, F

    2003-04-01

    This study investigates the techniques of nectar feeding in 11 different ant species, and quantitatively compares fluid intake rates over a wide range of nectar concentrations in four species that largely differ in their feeding habits. Ants were observed to employ two different techniques for liquid food intake, in which the glossa works either as a passive duct-like structure (sucking), or as an up- and downwards moving shovel (licking). The technique employed for collecting fluids at ad libitum food sources was observed to be species-specific and to correlate with the presence or absence of a well-developed crop in the species under scrutiny. Workers of ponerine ants licked fluid food during foraging and transported it as a droplet between their mandibles, whereas workers of species belonging to phylogenetically more advanced subfamilies, with a crop capable of storing liquids, sucked the fluid food, such as formicine ants of the genus Camponotus. In order to evaluate the performance of fluid collection during foraging, intake rates for sucrose solutions of different concentrations were measured in four ant species that differ in their foraging ecology. Scaling functions between fluid intake rates and ant size were first established for the polymorphic species, so as to compare ants of different size across species. Results showed that fluid intake rate depended, as expected and previously reported in the literature, on sugar concentration and the associated fluid viscosity. It also depended on both the species-specific feeding technique and the extent of specialization on foraging on liquid food. For similarly-sized ants, workers of two nectar-feeding ant species, Camponotus rufipes (Formicinae) and Pachycondyla villosa (Ponerinae), collected fluids with the highest intake rates, while workers of the leaf-cutting ant Atta sexdens (Myrmicinae) and a predatory ant from the Rhytidoponera impressa-complex (Ponerinae) did so with the lowest rate. Calculating the

  5. Fluid-flow-rate metrology: laboratory uncertainties and traceabilities

    Science.gov (United States)

    Mattingly, G. E.

    1991-03-01

    Increased concerns for improved fluid flowrate measurement are driving the fluid metering community-meter manufacturers and users alike-to search for better verification and documentation for their fluid measurements. These concerns affect both our domestic and international market places they permeate our technologies - aerospace chemical processes automotive bioengineering etc. They involve public health and safety and they impact our national defense. These concerns are based upon the rising value of fluid resources and products and the importance of critical material accountability. These values directly impact the accuracy needs of fluid buyers and sellers in custody transfers. These concerns impact the designers and operators of chemical process systems where control and productivity optimization depend critically upon measurement precision. Public health and safety depend upon the quality of numerous pollutant measurements - both liquid and gaseous. The performance testing of engines - both automotive and aircraft are critically based upon accurate fuel measurements - both liquid and oxidizer streams. Fluid flowrate measurements are established differently from counterparts in length and mass measurement systems because these have the benefits of " identity" standards. For rate measurement systems the metrology is based upon " derived standards" . These use facilities and transfer standards which are designed built characterized and used to constitute basic measurement capabilities and quantify performance - accuracy and precision. Because " identity standards" do not exist for flow measurements facsimiles or equivalents must

  6. Subchannel analysis with turbulent mixing rate of supercritical pressure fluid

    International Nuclear Information System (INIS)

    Wu, Jianhui; Oka, Yoshiaki

    2015-01-01

    Highlights: • Subchannel analysis with turbulent mixing rate law of supercritical pressure fluid (SPF) is carried out. • Turbulent mixing rate is enhanced, compared with that calculated by the law of pressurized water reactor (PWR). • Increase in maximum cladding surface temperature (MCST) is smaller comparing with PWR model. • The sensitivities of MCST on non-uniformity of subchannel area and power peaking are reduced by using SPF model. - Abstract: The subchannel analysis with turbulent mixing rate law of supercritical pressure fluid (SPF) is carried out for supercritical-pressurized light water cooled and moderated reactor (Super LWR). It is different from the turbulent mixing rate law of pressurized water reactor (PWR), which is widely adopted in Super LWR subchannel analysis study, the density difference between adjacent subchannels is taken into account for turbulent mixing rate law of SPF. MCSTs are evaluated on three kinds of fuel assemblies with different pin power distribution patterns, gap spacings and mass flow rates. Compared with that calculated by employing turbulent mixing rate law of PWR, the increase in MCST is smaller even when peaking factor is large and gap spacing is uneven. The sensitivities of MCST on non-uniformity of the subchannel area and power peaking are reduced

  7. Semiquantitative SPECT myocardial perfusion with dipyridamole in patients unable to exercise. Event rate during 4 years of follow up

    International Nuclear Information System (INIS)

    Balestrini, V.R.; Arja, V.J.; Sandrin, A.L.; Calvo, G.R.; Gomez Bosh, Z.; Quiroga, W.; Balestrini, C.E.; Joekes, S.

    2002-01-01

    The increasingly numbers of patients (P) that can't reach an adequate level of exercise in order to evaluate CAD, lead us to use pharmacological and technical tools available for this subgroup of P. Aim: evaluate the prognostic significance of myocardial perfusion SPECT imaging with pharmacological stress in P without LBBB, unable to exercise. Material and Methods: 209 P were included. Mean age: 65 years old (39-88), male 66%. Clinical: Pre test likelihood 8: 28%; SDS 0 and SRS 0: 31.7%; SDS 0 + SRS >=1: 21%; SDS >=1: 47.3%. III) Follow up: 13 patients were early re-vascularized induced by SPECT study results, 10 patients get lost and 186 were follow up by a mean 1086 days. Cumulative events rate: 1st year SCE 9.7%, HCE 1.6%; 2nd year SCE 14%, HCE 4.3%; 3rd year SCE 17.7%, HCE 5.4%; 4th year SCE 21%, HCE 5,4%. Scintigraphic indices and events rate relationship are presented. Conclusion: There was a relationship between scintigraphic indices and hard cardiac events. The semiquantitative myocardial perfusion with dipyridamole stress was a safe test and useful to discriminate groups of P with different risk of events

  8. Dependence of synchronized bursting activity on medium stirring and the perfusion rate in a cultured network of neurons

    Science.gov (United States)

    Heo, Ryoun; Kim, Hyun; Lee, Kyoung J.

    2016-05-01

    A cultured network of neurons coupled with a multi-electrode-array (MEA) recording system has been a useful platform for investigating various issues in neuroscience and engineering. The neural activity supported by the system can be sensitive to environmental fluctuations, for example, in the medium's nutrient composition, ph, and temperature, and to mechanical disturbances, yet this issue has not been the subject. Especially, a normal practice in maintaining neuronal cell cultures involves an intermittent sequence of medium exchanges, typically at a time interval of a few days, and one such sudden medium exchange is unavoidably accompanied by many unintended disturbances. Here, based on a quantitative time-series analysis of synchronized bursting events, we explicitly demonstrate that such a medium exchange can, indeed, bring a huge change in the existing neural activity. Subsequently, we develop a medium perfusion-stirring system and an ideal protocol that can be used in conjunction with a MEA recording system, providing long-term stability. Specifically, we systematically evaluate the effects of medium stirring and perfusion rates. Unexpectedly, even some vigorous mechanical agitations do not have any impacts on neural activity. On the other hand, too much replenishment ( e.g., 1.8 ml/day for a 1.8-ml dish) of neurobasal medium results in an excitotoxicity.

  9. Time required to achieve maximum concentration of amikacin in synovial fluid of the distal interphalangeal joint after intravenous regional limb perfusion in horses.

    Science.gov (United States)

    Kilcoyne, Isabelle; Nieto, Jorge E; Knych, Heather K; Dechant, Julie E

    2018-03-01

    OBJECTIVE To determine the maximum concentration (Cmax) of amikacin and time to Cmax (Tmax) in the distal interphalangeal (DIP) joint in horses after IV regional limb perfusion (IVRLP) by use of the cephalic vein. ANIMALS 9 adult horses. PROCEDURES Horses were sedated and restrained in a standing position and then subjected to IVRLP (2 g of amikacin sulfate diluted to 60 mL with saline [0.9% NaCl] solution) by use of the cephalic vein. A pneumatic tourniquet was placed 10 cm proximal to the accessory carpal bone. Perfusate was instilled with a peristaltic pump over a 3-minute period. Synovial fluid was collected from the DIP joint 5, 10, 15, 20, 25, and 30 minutes after IVRLP; the tourniquet was removed after the 20-minute sample was collected. Blood samples were collected from the jugular vein 5, 10, 15, 19, 21, 25, and 30 minutes after IVRLP. Amikacin was quantified with a fluorescence polarization immunoassay. Median Cmax of amikacin and Tmax in the DIP joint were determined. RESULTS 2 horses were excluded because an insufficient volume of synovial fluid was collected. Median Cmax for the DIP joint was 600 μg/mL (range, 37 to 2,420 μg/mL). Median Tmax for the DIP joint was 15 minutes. CONCLUSIONS AND CLINICAL RELEVANCE Tmax of amikacin was 15 minutes after IVRLP in horses and Cmax did not increase > 15 minutes after IVRLP despite maintenance of the tourniquet. Application of a tourniquet for 15 minutes should be sufficient for completion of IVRLP when attempting to achieve an adequate concentration of amikacin in the synovial fluid of the DIP joint.

  10. Nuclear magnetic resonance of perfused tissue

    International Nuclear Information System (INIS)

    Harpen, M.D.; Allison, R.C.

    1986-01-01

    The effect of perfusion on the NMR signal observed in NMR imaging is studied in a phantom and in two isolated perfused canine lungs. It is observed that perfusion in tissue has little effect on longitudinal relaxation times. Transverse relaxation rates are observed to correlate linearly with rates of perfusion, in accordance with a model presented. (author)

  11. Efficacy of perfusion cooling of the epidural space and cerebrospinal fluid drainage during repair of extent I and II thoracoabdominal aneurysm.

    Science.gov (United States)

    Tabayashi, K; Motoyoshi, N; Saiki, Y; Kokubo, H; Takahashi, G; Masuda, S; Shibuya, T; Akasaka, J; Oda, K; Kamata, M; Iguti, A

    2008-12-01

    The aim of this study was to evaluate spinal cord injury and mortality resulting from repair of extent I and II thoracoabdominal aneurysm. The authors compared patients operated under mild hypothermia with or without epidural perfusion cooling (EPC) and cerebrospinal fluid drainage (CSFD). From 1988 to 2007, 116 patients underwent replacement of the thoracoabdominal aorta; the procedure was performed in 38 patients with the aid of mild hypothermia alone (group A), and in 78 patients with the aid of EPC, mild hypothermia and CSFD (group B). Two catheters for epidural perfusion cooling were inserted in group B, in which one catheter was inserted into the epidural space to infuse chilled saline, and the other was inserted into the subdural space to drain the cerebrospinal fluid and to measure temperature and pressure. There were no significant differences in mean age, etiology of aortic disease, and aneurysm extent between the two groups. There were no significant differences in cardiopulmonary bypass time, the lowest nasopharyngeal temperature and operation time between the two study groups. The incidence of spinal cord injury in group A (16.2%) was significantly higher than in group B (3.8%, P=0.03). Hospital mortality in groups A and B was 10.5% and 2.6%, respectively (P=0.08). There was no significant difference in postoperative complications between the two study groups. The combination of EPC and CSFD was effective in lowering the incidence of postoperative spinal cord injury in the repair of extent I and II thoracoabdominal aortic aneurysm.

  12. Changes in ventilation–perfusion during and after an COPD exacerbation: an assessment using fluid dynamic modeling

    Directory of Open Access Journals (Sweden)

    Hajian B

    2018-03-01

    Full Text Available Bita Hajian,1 Jan De Backer,2 Wim Vos,2 Wouter H van Geffen,3 Paul De Winter,1 Omar Usmani,4 Tony Cahn,5 Huib AM Kerstjens,3 Massimo Pistolesi,6 Wilfried De Backer1 1Department of Respiratory Medicine, University Hospital Antwerp, Edegem, Belgium; 2FLUIDDA nv, Kontich, Belgium; 3Department of Respiratory Medicine, University Medical Center Groningen, Groningen, the Netherlands; 4Department of Pulmonology, Brompton Hospital, London, UK; 5GSK, London, UK; 6Department of Pulmonary Diseases, University of Firenze, Florence, Italy Introduction: Severe exacerbations associated with chronic obstructive pulmonary disease (COPD that require hospitalization significantly contribute to morbidity and mortality. Definitions for exacerbations are very broad, and it is unclear whether there is one predominant underlying mechanism that leads to them. Functional respiratory imaging (FRI with modeling provides detailed information about airway resistance, hyperinflation, and ventilation–perfusion (V/Q mismatch during and following an acute exacerbation. Materials and methods: Forty-two patients with COPD participating in a multicenter study were assessed by FRI, pulmonary function tests, and self-reported outcome measures during an acute exacerbation and following resolution. Arterial blood gasses and lung function parameters were measured. Results: A significant correlation was found between alveolar–arterial gradient and image-based V/Q (iV/Q, suggesting that iV/Q represents V/Q mismatch during an exacerbation (p<0.05. Conclusion: Recovery of an exacerbation is due to decreased (mainly distal airway resistance (p<0.05. Improvement in patient-reported outcomes were also associated with decreased distal airway resistance (p<0.05, but not with forced expiratory volume. FRI is, therefore, a sensitive tool to describe changes in airway caliber, ventilation, and perfusion during and after exacerbation. On the basis of the fact that FRI increased distal airway

  13. The effect of relaxing music on heart rate and heart rate variability during ECG GATED-myocardial perfusion scintigraphy.

    Science.gov (United States)

    Tan, Yusuf Ziya; Ozdemir, Semra; Temiz, Ahmet; Celik, Fatmanur

    2015-05-01

    The positive changes in human behavior caused by relaxing music demonstrate the psychological effect of music on human body. A meta-analytical study has shown that relaxing music affects blood pressure and heart rate in coronary heart patients and cancer patients. The aim of our study is to research whether there is a significant effect on heart rate and heart rate variability due to listening to relaxing music during ECG GATED MPS imaging under gamma camera. The music group (n = 50 patients) could choose from 15 different musical types including folk music (no lyric). The other 50 patients were placed in a "no music group" and did not get headphones or any music. There was a statistically significant reduction in the heart rate of patients in the music group compared to those in the control group. Relaxing music provides great benefits to both patient and clinician. There is close relationship between relaxing music and health procedure, can use every area of the health noninvasiv, safe, cheap and is a method don't have side effect. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Quantitative cerebral H215O perfusion PET without arterial blood sampling, a method based on washout rate

    International Nuclear Information System (INIS)

    Treyer, Valerie; Jobin, Mathieu; Burger, Cyrill; Buck, Alfred; Teneggi, Vincenzo

    2003-01-01

    The quantitative determination of regional cerebral blood flow (rCBF) is important in certain clinical and research applications. The disadvantage of most quantitative methods using H 2 15 O positron emission tomography (PET) is the need for arterial blood sampling. In this study a new non-invasive method for rCBF quantification was evaluated. The method is based on the washout rate of H 2 15 O following intravenous injection. All results were obtained with Alpert's method, which yields maps of the washin parameter K 1 (rCBF K1 ) and the washout parameter k 2 (rCBF k2 ). Maps of rCBF K1 were computed with measured arterial input curves. Maps of rCBF k2* were calculated with a standard input curve which was the mean of eight individual input curves. The mean of grey matter rCBF k2* (CBF k2* ) was then compared with the mean of rCBF K1 (CBF K1 ) in ten healthy volunteer smokers who underwent two PET sessions on day 1 and day 3. Each session consisted of three serial H 2 15 O scans. Reproducibility was analysed using the rCBF difference scan 3-scan 2 in each session. The perfusion reserve (PR = rCBF acetazolamide -rCBF baseline ) following acetazolamide challenge was calculated with rCBF k2* (PR k2* ) and rCBF K1 (PR K1 ) in ten patients with cerebrovascular disease. The difference CBF k2* -CBF K1 was 5.90±8.12 ml/min/100 ml (mean±SD, n=55). The SD of the scan 3-scan 1 difference was 6.1% for rCBF k2* and rCBF K1 , demonstrating a high reproducibility. Perfusion reserve values determined with rCBF K1 and rCBF k2* were in high agreement (difference PR k2* -PR K1 =-6.5±10.4%, PR expressed in percentage increase from baseline). In conclusion, a new non-invasive method for the quantitative determination of rCBF is presented. The method is in good agreement with Alpert's original method and the reproducibility is high. It does not require arterial blood sampling, yields quantitative voxel-by-voxel maps of rCBF, and is computationally efficient and easy to implement

  15. Note: A micro-perfusion system for use during real-time physiological studies under high pressure

    Science.gov (United States)

    Maltas, Jeff; Long, Zac; Huff, Alison; Maloney, Ryan; Ryan, Jordan; Urayama, Paul

    2014-10-01

    We construct a micro-perfusion system using piston screw pump generators for use during real-time, high-pressure physiological studies. Perfusion is achieved using two generators, with one generator being compressed while the other is retracted, thus maintaining pressurization while producing fluid flow. We demonstrate control over perfusion rates in the 10-μl/s range and the ability to change between fluid reservoirs at up to 50 MPa. We validate the screw-pump approach by monitoring the cyanide-induced response of UV-excited autofluorescence from Saccharomyces cerevisiae under pressurization.

  16. Fluid queues driven by a birth and death process with alternating flow rates

    OpenAIRE

    P. R. Parthasarathy; K. V. Vijayashree; R. B. Lenin

    2004-01-01

    Fluid queue driven by a birth and death process (BDP) with only one negative effective input rate has been considered in the literature. As an alternative, here we consider a fluid queue in which the input is characterized by a BDP with alternating positive and negative flow rates on a finite state space. Also, the BDP has two alternating arrival rates and two alternating service rates. Explicit expression for the distribution function of the buffer occupancy is obtained. The case where the s...

  17. Peritoneal fluid transport in CAPD patients with different transport rates of small solutes.

    Science.gov (United States)

    Sobiecka, Danuta; Waniewski, Jacek; Weryński, Andrzej; Lindholm, Bengt

    2004-01-01

    Continuous ambulatory peritoneal dialysis (CAPD) patients with high peritoneal solute transport rate often have inadequate peritoneal fluid transport. It is not known whether this inadequate fluid transport is due solely to a too rapid fall of osmotic pressure, or if the decreased effectiveness of fluid transport is also a contributing factor. To analyze fluid transport parameters and the effectiveness of dialysis fluid osmotic pressure in the induction of fluid flow in CAPD patients with different small solute transport rates. 44 CAPD patients were placed in low (n = 6), low-average (n = 13), high-average (n = 19), and high (n = 6) transport groups according to a modified peritoneal equilibration test (PET). The study involved a 6-hour peritoneal dialysis dwell with 2 L 3.86% glucose dialysis fluid for each patient. Radioisotopically labeled serum albumin was added as a volume marker.The fluid transport parameters (osmotic conductance and fluid absorption rate) were estimated using three mathematical models of fluid transport: (1) Pyle model (model P), which describes ultrafiltration rate as an exponential function of time; (2) model OS, which is based on the linear relationship of ultrafiltration rate and overall osmolality gradient between dialysis fluid and blood; and (3) model G, which is based on the linear relationship between ultrafiltration rate and glucose concentration gradient between dialysis fluid and blood. Diffusive mass transport coefficients (K(BD)) for glucose, urea, creatinine, potassium, and sodium were estimated using the modified Babb-Randerson-Farrell model. The high transport group had significantly lower dialysate volume and glucose and osmolality gradients between dialysate and blood, but significantly higher K(BD) for small solutes compared with the other transport groups. Osmotic conductance, fluid absorption rate, and initial ultrafiltration rate did not differ among the transport groups for model OS and model P. Model G yielded

  18. A Review of Liver Perfusion Method in Toxicology Studies

    Directory of Open Access Journals (Sweden)

    M karami

    2014-06-01

    Full Text Available Introduction: The isolated perfused rat liver is an accepted method in toxicology studies. The isolated perfused rat liver (IPRL is a useful experimental system for evaluating hepatic function without the influence of other organ systems, undefined plasma constituents, and neural-hormonal effects. Methods: The untreated male rats (180-220gr body weight were anesthetised with ether and then surgery with proper method. The abdomen was opened through a midline and one transversal incision and the bile duct was cannulated. Heparin sodium solution (0.5 ml; 500 U/ml in 0.9% NaCl was injected via the abdominal vena cava to prevent blood clotting. The liver inferior venacava was cannulated with PE-10 tubing and secured. The portal vein was immediately cannulated with an 23gr catheter which was secured and then liver was perfused in situ by Krebs- Henseleit buffer (pH 7.4; saturated with 95% O2 and 5% CO2; 37°C at a flow rate of 20 ml/min for 3hr. Temperature, perfusion pressure, flow rate and perfusion fluid pH were closely monitored during the perfusion. Results: Transferase enzymes (ALT, AST alterations can be widely used as a measure of biochemical alterations in order to assess liver damage due to use of drugs such as isoniazid (INH and animal and plant toxins. Accumulated material in gallbladder are valuable samples to assess the level of Glutathione (GSH. Sections of perfused liver tissue can also be effectively analyzed for pathological aspects such as necrosis, fibrosis, cellularity. Conclusion: The isolated perfused rat liver (IPRL is a useful and Sutible experimental system for evaluating hepatic function. In this system, the effects of adjacent organs, on the liver is minimized

  19. Post-Exercise Rehydration Strategies: Rate of Fluid Intake and Beverage Type

    Directory of Open Access Journals (Sweden)

    María de Lourdes Mayol Soto

    2010-08-01

    Full Text Available The purpose of the present study was to investigate the effect of a high (H and a low (L rate of fluid consumption with plain water (W or a sports drink (SD on post-exercise fluid balance, and to evaluate whether the known differences between beverages depend on the fluid ingestion rate. Active male subjects (n=16 performed four trials in random order. The participants arrived to the trials euhydrated and were dehydrated to 2% of body weight (BW by cycling intermittently in a controlled climate room (30-35úC. After 30 min of rest, they ingested either W or SD in a volume equivalent to 150% of BW loss, in 45 min (high rate, R or 165 min (low rate, L. At the time point coinciding with the end of H, urine samples were collected every 30 min for four hours. BW loss was similar for all trials and resulted in a total fluid consumption of 2.48 + 0.4 l. Overall, urine output in W exceeded significantly that of SD in both rates of fluid consumption (p=0.001, but there were no differences between L and R (p=0.378. Subjects finished in negative fluid balance in all trials. It is concluded that SD resulted in better but incomplete restoration of fluid balance than W, independent of the rate of fluid consumption. Although overall fluid balance was the same with both ingestion rates (L and H, L was more comfortable to the subjects.

  20. Method and apparatus for simultaneous determination of fluid mass flow rate, mean velocity and density

    International Nuclear Information System (INIS)

    Hamel, W.R.

    1984-01-01

    This invention relates to a new method and new apparatus for determining fluid mass flow rate and density. In one aspect of the invention, the fluid is passed through a straight cantilevered tube in which transient oscillation has been induced, thus generating Coriolis damping forces on the tube. The decay rate and frequency of the resulting damped oscillation are measured, and the fluid mass flow rate and density are determined therefrom. In another aspect of the invention, the fluid is passed through the cantilevered tube while an electrically powered device imparts steady-state harmonic excitation to the tube. This generates Coriolis tube-damping forces which are dependent on the mass flow rate of the fluid. Means are provided to respond to incipient flow-induced changes in the amplitude of vibration by changing the power input to the excitation device as required to sustain the original amplitude of vibration. The fluid mass flow rate and density are determined from the required change in power input. The invention provides stable, rapid, and accurate measurements. It does not require bending of the fluid flow

  1. Male mating rate is constrained by seminal fluid availability in bedbugs, Cimex lectularius.

    Directory of Open Access Journals (Sweden)

    Klaus Reinhardt

    Full Text Available Sexual selection, differences in reproductive success between individuals, continues beyond acquiring a mating partner and affects ejaculate size and composition (sperm competition. Sperm and seminal fluid have very different roles in sperm competition but both components encompass production costs for the male. Theoretical models predict that males should spend ejaculate components prudently and differently for sperm and seminal fluid but empirical evidence for independent variation of sperm number and seminal fluid volume is scarce. It is also largely unknown how sperm and seminal fluid variation affect future mating rate. In bedbugs we developed a protocol to examine the role of seminal fluids in ejaculate allocation and its effect on future male mating rate. Using age-related changes in sperm and seminal fluid volume we estimated the lowest capacity at which mating activity started. We then showed that sexually active males allocate 12% of their sperm and 19% of their seminal fluid volume per mating and predicted that males would be depleted of seminal fluid but not of sperm. We tested (and confirmed this prediction empirically. Finally, the slightly faster replenishment of seminal fluid compared to sperm did not outweigh the faster decrease during mating. Our results suggest that male mating rate can be constrained by the availability of seminal fluids. Our protocol might be applicable to a range of other organisms. We discuss the idea that economic considerations in sexual conflict research might benefit from distinguishing between costs and benefits that are ejaculate dose-dependent and those that are frequency-dependent on the mating rate per se.

  2. Method of measuring the mass flow rate of a substance entering a cocurrent fluid stream

    International Nuclear Information System (INIS)

    Cochran, H.D. Jr.

    1978-01-01

    An improved method of monitoring the mass flow rate of a substance entering a coherent fluid stream is described. The method very basically consists of heating equal sections of the fluid stream above and below the point of entry of the substance to be monitored, and measuring and comparing the resulting change in temperature of the sections. Advantage is taken of the difference in thermal characteristics of the fluid and the substance to be measured to correlate temperature differences in the sections above and below the substance feed point for providing an indication of the mass flow rate of the substance

  3. Renal perfusion scintiscan

    Science.gov (United States)

    ... Radionuclide renal perfusion scan; Perfusion scintiscan - renal; Scintiscan - renal perfusion Images Kidney anatomy Kidney - blood and urine flow Intravenous pyelogram References Rottenberg G, Andi AC. Renal ...

  4. The Effect of Heart Rate on Exposure Window and Best Phase for Stress Perfusion Computed Tomography: Lessons From the CORE320 Study.

    Science.gov (United States)

    Steveson, Chloe; Schuijf, Joanne D; Vavere, Andrea L; Mather, Richard T; Caton, Teresa; Mehra, Vishal; Betoko, Aisha; Cox, Christopher; Lima, Joao Ac; George, Richard T

    The aim of this study is to evaluate the effect of heart rate on exposure window, best phase, and image quality for stress computed tomography perfusion (CTP) in the CORE320 study. The CTP data sets were analyzed to determine the best phase for perfusion analysis. A predefined exposure window covering 75% to 95% of the R-R cycle was used. Of the 368 patients included in the analysis, 93% received oral β blockade before the rest scan. The median heart rate during the stress acquisition was 69 bpm (interquartile range [IQR], 60-77). The median best phase was 81% (IQR, 76-90), and length of exposure window was 22% (IQR, 19-24). The best phase was significantly later in the cardiac cycle with higher heart rates (P stress scan was 5.3 mSv (IQR, 3.8-6.1). Stress myocardial CTP imaging can be performed using prospective electrocardiography triggering, an exposure window of 75% to 95%, and β-blockade resulting in good or excellent image quality in the majority (80%) of patients while maintaining a low effective radiation dose.

  5. First general solutions for unidirectional motions of rate type fluids over an infinite plate

    Directory of Open Access Journals (Sweden)

    Constantin Fetecau

    2015-09-01

    Full Text Available Based on a simple but important remark regarding the governing equation for the non-trivial shear stress corresponding to the motion of a fluid over an infinite plate, exact solutions are established for the motion of Oldroyd-B fluids due to the plate that applies an arbitrary time-dependent shear stress to the fluid. These solutions, that allow us to provide the first exact solutions for motions of rate type fluids produced by an infinite plate that applies constant, constantly accelerating or oscillating shears stresses to the fluid, can easily be reduced to the similar solutions for Maxwell, second grade or Newtonian fluids performing the same motion. Furthermore, the obtained solutions are used to develop general solutions for the motion induced by a moving plate and to correct or recover as special cases different known results from the existing literature. Consequently, the motion problem of such fluids over an infinite plate that is moving in its plane or applies a shear stress to the fluid is completely solved.

  6. Effect of endometrial cavity fluid on pregnancy rate of fresh versus frozen In Vitro fertilization cycle

    Directory of Open Access Journals (Sweden)

    Nitika Gupta

    2017-01-01

    Full Text Available Objective: This study aims to study the difference in etiology and outcome in terms of implantation rate and abortion rate in fresh (self-stimulated versus frozen (oocyte donation cycle in vitro fertilization (IVF and in transient versus persistent fluid. Material and Methods: This retrospective study was conducted in the Department of Reproductive Medicine of tertiary care center from January 2012 to November 2015. Data were collected retrospectively from the departmental files. Twenty-four patients from fresh IVF-stimulated cycles and 24 from frozen oocyte donation cycle with their endometrium prepared by hormone replacement treatment were included in the study. All patients selected in the study had grade-A embryo transfer of day 3–4 with maximum three embryo transferred. Pregnancy was defined by rising serum beta-human chorionic gonadotrophin levels performed after 14 days of embryo transfer and further confirmed by ultrasonographic visualization of gestational sac at 6 weeks. All biochemical pregnancies were included in implantation failure. All pregnant patients were followed till the termination of pregnancy and further noted as live birth or abortion. Results: Clinical pregnancy rate was seen more in self-stimulated cycle (62.5% with live birth rate of 50% than hormone replacement treatment cycle, in which clinical pregnancy rate was 45.83% with live birth rate of 33.33%. Clinical pregnancy rate was highest in group with very less fluid in cavity (1–2 mm 63% and with live birth of 52.63%. Clinical pregnancy was seen only in two patients of group B with anterior and posterior (AP diameter of fluid in cavity of 2–3 mm with live birth of only one, whereas in group C, with AP diameter of 3–5 mm, none of the patient conceived. This difference was statistically significant. Clinical pregnancy rate was 65.62% in transient fluid accumulation with live birth rate of 53.25%, which was significantly higher than persistent fluid accumulation

  7. Intravenous fluid rate for reduction of cesarean delivery rate in nulliparous women: a systematic review and meta-analysis.

    Science.gov (United States)

    Ehsanipoor, Robert M; Saccone, Gabriele; Seligman, Neil S; Pierce-Williams, Rebecca A M; Ciardulli, Andrea; Berghella, Vincenzo

    2017-07-01

    The National Institute of Child Health and Human Development, American College of Obstetricians and Gynecologists, and Society for Maternal-Fetal Medicine have emphasized the need to promote vaginal delivery and have offered recommendations to safely prevent primary cesarean delivery. However, there has been limited discussion regarding management of intravenous fluids and other aspects of labor management that may influence mode of delivery. Therefore the aim of our study was to determine whether an intravenous fluid rate of 250 vs. 125 mL/h is associated with a difference in cesarean delivery rate. Searches were performed in MEDLINE, OVID, Scopus, ClinicalTrials.gov, the PROSPERO International Prospective Register of Systematic Reviews, Embase, Web of Science, and the Cochrane Library for randomized controlled trials. We included all randomized controlled trials comparing intravenous fluid rates of 250 vs. 125 mL/h in nulliparous women in spontaneous labor at term with singleton pregnancies at ≥36 weeks. Studies were included regardless of the type of intravenous fluids used and regardless of whether oral intake was restricted during labor. Studies including multiparous women or women whose labor was induced were excluded. The primary outcome was the incidence of cesarean delivery. We planned to assess a subgroup analysis according to type of fluids used and according to restriction of oral fluid intake. Seven trials including 1215 nulliparous women in spontaneous labor at term were analyzed; 593 (48.8%) in the 250 mL/h group, and 622 (51.2%) in the 125 mL/h group. Five studies used lactated Ringer's solution, one used normal saline in dextrose water, and in one study it was unclear which intravenous fluid was used. Women who received intravenous fluids at 250 mL/h had a significantly lower incidence of cesarean delivery for any indication (12.5 vs. 18.1%; RR 0.70, 95% CI 0.53-0.92; seven studies, 1215 participants; I 2 = 0%) and for dystocia (4.9 vs. 7.7%; RR

  8. Pelvic endometriosis with peritoneal fluid reduces pregnancy rates in women undergoing intrauterine insemination.

    Science.gov (United States)

    Wu, Hong-Ming; Tzeng, Chii-Ruey; Chen, Chi-Hung; Chen, Pi-Hua

    2013-12-01

    This study investigated the occurrence of peritoneal fluid in women undergoing intrauterine insemination (IUI) and its correlation with the stage of pelvic endometriosis and its influence on pregnancy outcomes. A retrospective case-control design was used to recruit 272 infertile women with pelvic endometriosis. The treatment protocol consisted of controlled ovarian hyperstimulation with downregulation and gonadotropin for IUI treatment following ultrasound and laparoscopic intervention. The amount and color of the peritoneal fluid were determined during laparoscopy. The mean amount of peritoneal fluid with pelvic endometriosis that was detected using transvaginal ultrasound was ~ 15.1 mL. Women whose cycles contained more peritoneal fluid had significantly lower pregnancy rates (17.2% and 31.3%, respectively). The total clinical pregnancy rate was not significantly different between the two groups with reddish and yellowish peritoneal fluid who had pelvic endometriosis. Pelvic endometriosis and peritoneal fluid, detected through vaginal ultrasound, have negative effects on the pregnancy outcome of IUI treatment. Copyright © 2013. Published by Elsevier B.V.

  9. Increasing Biogas Production Rate from Cattle Manure Using Rumen Fluid as Inoculums

    Directory of Open Access Journals (Sweden)

    Budiyono Budiyono

    2013-10-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 In this study, rumen fluid of animal ruminant was used as inoculums to increase biogas production rate from cattle manure at mesophilic condition. A series of laboratory experiments using 400 ml biodigester were performed in batch operation mode. Given 100 grams of fresh cattle manure (M was fed to each biodigester and mixed with rumen fluid (R and tap water (W in several ratio resulting six different M:W:R ratio contents i.e. 1:1:0; 1:0.75:0.25; 1:0.5:0.5; 1:0.25:0.75; and 1:0:1 (correspond to 0; 12.5; 25, 37.5; 50, and 100 % rumen, respectively and six different total solid (TS contents i.e. 2.6, 4.6, 6.2, 7.4, 9.2, 12.3, and 18.4 %. The operating temperatures were at room temperature. The results showed that the rumen fluid inoculated to biodigester significantly effected the biogas production. Rumen fluid inoculums caused biogas production rate and efficiency increase more than two times in compare to manure substrate without rumen fluid inoculums. The best performance for biogas production was the digester with rumen fluid and TS content in the range of 25-50 % and 7.4 and 9.2 %, respectively. These results suggest that, based on TS content effects to biogas yield, rumen fluid inoculums exhibit the similar effect with other inoculums. Increasing rumen content will also increase biogas production. Due to the optimum total solid (TS content for biogas production between 7-9 % (or correspond to more and less manure and total liquid 1:1, the rumen fluid content of 50 % will give the best performance for biogas production. The future work will be carried out to study the dynamics of biogas production if both the rumen fluid inoculums and manure are fed in the continuous system Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Doi: 10.12777/ijse.6.1.31-38 [How to cite this article: Budiyono, Widiasa, I.N., Johari, S. and Sunarso. (2014. Increasing Biogas

  10. Development and evaluation of a meter for measuring return line fluid flow rates during drilling

    Energy Technology Data Exchange (ETDEWEB)

    Loeppke, G.E.; Schafer, D.M.; Glowka, D.A.; Scott, D.D.; Wernig, M.D. (Sandia National Labs., Albuquerque, NM (United States)); Wright, E.K. (Ktech Corp., Albuquerque, NM (United States))

    1992-06-01

    The most costly problem routinely encountered in geothermal drilling is lost circulation, which occurs when drilling fluid is lost to the formation rather than circulating back to the surface. The successful and economical treatment of lost circulation requires the accurate measurement of drilling fluid flow rate both into and out of the well. This report documents the development of a meter for measuring drilling fluid outflow rates in the return line of a drilling rig. The meter employs a rolling counterbalanced float that rides on the surface of the fluid in the return line. The angle of the float pivot arm is sensed with a pendulum potentiometer, and the height of the float is calculated from this measurement. The float height is closely related to the fluid height and, therefore, the flow rate in the line. The prototype rolling float meter was extensively tested under laboratory conditions in the Wellbore Hydraulics Flow Facility; results from these tests were used in the design of the field prototype rolling float meter. The field prototype meter was tested under actual drilling conditions in August and September 1991 at the Long Valley Exploratory Well near Mammoth Lakes, Ca. In addition, the performance of several other commercially available inflow and outflow meters was evaluated in the field. The tested inflow meters included conventional pump stroke counters, rotary pump speed counters, magnetic flowmeters, and an ultrasonic Doppler flowmeter. On the return flow line, a standard paddlemeter, an acoustic level meter, and the prototype rolling float meter were evaluated for measuring drilling fluid outflow rates.

  11. Reasons for the low flowback rates of fracturing fluids in marine shale

    Directory of Open Access Journals (Sweden)

    Yongjun Lu

    2018-02-01

    Full Text Available In this paper, marine shale cores taken from Zhaotong, Changning and Weiyuan Blocks in South China were used as samples to investigate the interaction between fracturing fluids and shale and the retention mechanisms. Firstly, adsorption, swelling, dissolution pore, dissolution fluid mineralization degree and ionic composition were experimentally studied to reveal the occurrence of water in shale and the reason for a high mineralization degree. Then, the mechanisms of water retention and mineralization degree increase were simulated and calculated. The scanning electron microscopy (SEM analysis shows that there are a large number of micro fractures originated from clay minerals in the shale. Mineral dissolution rates of shale immersed in ultrasonic is around 0.5–0.7%. The ionic composition is in accordance with that of formation water. The clay minerals in core samples are mainly composed of chlorites and illites with a small amount of illites/smectites, but no montmorillonites (SS, and its content is between 18% and 20%. It is verified by XRD and infrared spectroscopy that the fracturing fluid doesn't flow into the space between clay mineral layers, so it can't lead to shale swelling. Thus, the retention of fracturing fluids is mainly caused by the adsorption at the surface of the newly fractured micro fractures in shale in a mode of successive permeation, and its adsorptive saturation rates is proportional to the pore diameters. It is concluded that the step-by-step extraction of fracturing fluids to shale and the repulsion of nano-cracks to ion are the main reasons for the abrupt increase of mineralization degree in the late stage of flowing back. In addition, the liquid carrying effect of methane during the formation of a gas reservoir is also a possible reason. Based on the experimental and field data, fracturing fluid flowback rates and gas production rates of 9 wells were analyzed. It is indicated that the same block follows an overall

  12. Magnetic resonance perfusion imaging without contrast media

    International Nuclear Information System (INIS)

    Martirosian, Petros; Graf, Hansjoerg; Schick, Fritz; Boss, Andreas; Schraml, Christina; Schwenzer, Nina F.; Claussen, Claus D.

    2010-01-01

    Principles of magnetic resonance imaging techniques providing perfusion-related contrast weighting without administration of contrast media are reported and analysed systematically. Especially common approaches to arterial spin labelling (ASL) perfusion imaging allowing quantitative assessment of specific perfusion rates are described in detail. The potential of ASL for perfusion imaging was tested in several types of tissue. After a systematic comparison of technical aspects of continuous and pulsed ASL techniques the standard kinetic model and tissue properties of influence to quantitative measurements of perfusion are reported. For the applications demonstrated in this paper a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion preparation approach followed by true fast imaging with steady precession (true FISP) data recording was developed and implemented on whole-body scanners operating at 0.2, 1.5 and 3 T for quantitative perfusion measurement in various types of tissue. ASL imaging provides a non-invasive tool for assessment of tissue perfusion rates in vivo. Images recorded from kidney, lung, brain, salivary gland and thyroid gland provide a spatial resolution of a few millimetres and sufficient signal to noise ratio in perfusion maps after 2-5 min of examination time. Newly developed ASL techniques provide especially high image quality and quantitative perfusion maps in tissues with relatively high perfusion rates (as also present in many tumours). Averaging of acquisitions and image subtraction procedures are mandatory, leading to the necessity of synchronization of data recording to breathing in abdominal and thoracic organs. (orig.)

  13. Material Removal Rate for Magnetorheological Finishing (MRF) of Optical Glasses with Nanodiamond MR Fluid

    International Nuclear Information System (INIS)

    DeGroote, J.E.; Marino, A.E.; Wilson, J.P.; Bishop, A.L.; Jacobs, S.D.

    2007-01-01

    We present a material removal rate model for MRF of optical glasses using nanodiamond MR fluid. The new model incorporates terms for drag force, polishing particle properties, chemical durability and glass composition into an existing model that contains only terms for the glass mechanical properties. Experimental results for six optical glasses are given that support this model

  14. Flow rate control in pressure-programmed capillary supercritical fluid chromatography

    NARCIS (Netherlands)

    Janssen, J.G.M.; Rijks, J.A.; Cramers, C.A.M.G.

    1990-01-01

    A versatile and simple system is described that allows variation of the column flow rate in open-tubular capillary supercritical fluid chromatography using both on-column and postcolumn detection. The system is based on column-effluent splitting in a low-dead-volume T piece at the column exit just

  15. Material Removal Rate for Magnetorheological Finishing (MRF) of Optical Glasses with Nanodiamond MR Fluid

    Energy Technology Data Exchange (ETDEWEB)

    DeGroote, J.E.; Marino, A.E.; Wilson, J.P.; Bishop, A.L.; Jacobs, S.D.

    2007-07-13

    We present a material removal rate model for MRF of optical glasses using nanodiamond MR fluid. The new model incorporates terms for drag force, polishing particle properties, chemical durability and glass composition into an existing model that contains only terms for the glass mechanical properties. Experimental results for six optical glasses are given that support this model.

  16. Hydrostatic determinants of cerebral perfusion

    International Nuclear Information System (INIS)

    Wagner, E.M.; Traystman, R.J.

    1986-01-01

    We examined the cerebral blood flow response to alterations in perfusion pressure mediated through decreases in mean arterial pressure, increases in cerebrospinal fluid (CSF) pressure, and increases in jugular venous (JV) pressure in 42 pentobarbital anesthetized dogs. Each of these three pressures was independently controlled. Cerebral perfusion pressure was defined as mean arterial pressure minus JV or CSF pressure, depending on which was greater. Mean hemispheric blood flow was measured with the radiolabeled microsphere technique. Despite 30-mm Hg reductions in mean arterial pressure or increases in CSF or JV pressure, CBF did not change as long as the perfusion pressure remained greater than approximately 60 mm Hg. However, whenever perfusion pressure was reduced to an average of 48 mm Hg, cerebral blood flow decreased 27% to 33%. These results demonstrate the capacity of the cerebral vascular bed to respond similarly to changes in the perfusion pressure gradient obtained by decreasing mean arterial pressure, increasing JV pressure or increasing CSF pressure, and thereby support the above definition of cerebral perfusion pressure

  17. Fluid Flow Behaviour under Different Gases and Flow Rate during Gas Metal Arc Welding

    OpenAIRE

    Jaison Peter

    2013-01-01

    Gas metal arc welding (GMAW) is a highly efficient and fast process for fabricating high quality weld. High quality welds are fabricated by proper selection of consumable includes gas and filler metals. The optimum flow rate of gas will ensure the proper quality of weld. In this project, a fluid flow behavior of different flow rate is modeled and the change quality will be studied.

  18. Placental perfusion - a human alternative

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E

    2006-01-01

    Foetal exposures to environmental and medicinal products have impact on the growth of the foetus (e.g. cigarette smoke) and development of organs (e.g. methylmercury and Thalidomide). Perfusion studies of the human term placenta enable investigation of placental transport of chemical substances...... between the mother and foetus. Dual perfusion of a single cotyledon in the human placenta can contribute to a better understanding of the placental barrier, transport rate and mechanisms of different substances and placental metabolism. The perfusion system has recently been established in Copenhagen...

  19. Finite element approximation of flow of fluids with shear-rate- and pressure-dependent viscosity

    Czech Academy of Sciences Publication Activity Database

    Hirn, A.; Lanzendörfer, Martin; Stebel, Jan

    2012-01-01

    Roč. 32, č. 4 (2012), s. 1604-1634 ISSN 0272-4979 R&D Projects: GA ČR GA201/09/0917; GA AV ČR IAA100300802; GA MŠk LC06052 Institutional research plan: CEZ:AV0Z10300504; CEZ:AV0Z10190503 Keywords : non-Newtonian fluid * shear-rate- and pressure-dependent viscosity * finite element method * error analysis Subject RIV: BK - Fluid Dynamics Impact factor: 1.326, year: 2012

  20. Characterization of commercial magnetorheological fluids at high shear rate: influence of the gap

    Science.gov (United States)

    Golinelli, Nicola; Spaggiari, Andrea

    2018-07-01

    This paper reports the experimental tests on the behaviour of a commercial MR fluid at high shear rates and the effect of the gap. Three gaps were considered at multiple magnetic fields and shear rates. From an extended set of almost two hundred experimental flow curves, a set of parameters for the apparent viscosity are retrieved by using the Ostwald de Waele model for non-Newtonian fluids. It is possible to simplify the parameter correlation by making the following considerations: the consistency of the model depends only on the magnetic field, the flow index depends on the fluid type and the gap shows an important effect only at null or very low magnetic fields. This lead to a simple and useful model, especially in the design phase of a MR based product. During the off state, with no applied field, it is possible to use a standard viscous model. During the active state, with high magnetic field, a strong non-Newtonian nature becomes prevalent over the viscous one even at very high shear rate; the magnetic field dominates the apparent viscosity change, while the gap does not play any relevant role on the system behaviour. This simple assumption allows the designer to dimension the gap only considering the non-active state, as in standard viscous systems, and taking into account only the magnetic effect in the active state, where the gap does not change the proposed fluid model.

  1. Detecting subsurface fluid leaks in real-time using injection and production rates

    Science.gov (United States)

    Singh, Harpreet; Huerta, Nicolas J.

    2017-12-01

    CO2 injection into geologic formations for either enhanced oil recovery or carbon storage introduces a risk for undesired fluid leakage into overlying groundwater or to the surface. Despite decades of subsurface CO2 production and injection, the technologies and methods for detecting CO2 leaks are still costly and prone to large uncertainties. This is especially true for pressure-based monitoring methods, which require the use of simplified geological and reservoir flow models to simulate the pressure behavior as well as background noise affecting pressure measurements. In this study, we propose a method to detect the time and volume of fluid leakage based on real-time measurements of well injection and production rates. The approach utilizes analogies between fluid flow and capacitance-resistance modeling. Unlike other leak detection methods (e.g. pressure-based), the proposed method does not require geological and reservoir flow models to simulate the behavior that often carry significant sources of uncertainty; therefore, with our approach the leak can be detected with greater certainty. The method can be applied to detect when a leak begins by tracking a departure in fluid production rate from the expected pattern. The method has been tuned to detect the effect of boundary conditions and fluid compressibility on leakage. To highlight the utility of this approach we use our method to detect leaks for two scenarios. The first scenario simulates a fluid leak from the storage formation into an above-zone monitoring interval. The second scenario simulates intra-reservoir migration between two compartments. We illustrate this method to detect fluid leakage in three different reservoirs with varying levels of geological and structural complexity. The proposed leakage detection method has three novelties: i) requires only readily-available data (injection and production rates), ii) accounts for fluid compressibility and boundary effects, and iii) in addition to

  2. Seismicity rate surge on faults after shut-in: poroelastic response to fluid injection

    Science.gov (United States)

    Chang, K. W.; Yoon, H.; Martinez, M. J.

    2017-12-01

    Subsurface energy activities such as geological CO2 storage and wastewater injection require injecting large amounts of fluid into the subsurface, which will alter the states of pore pressure and stress in the storage formation. One of the main issues for injection-induced seismicity is the post shut-in increases in the seismicity rate, often observed in the fluid-injection operation sites. The rate surge can be driven by the following mechanisms: (1) pore-pressure propagation into distant faults after shut-in and (2) poroelastic stressing caused by well operations, depending on fault geometry, hydraulic and mechanical properties of the formation, and injection history. We simulate the aerial view of the target reservoir intersected by strike-slip faults, in which injection-induced pressure buildup encounters the faults directly. We examine the poroelastic response of the faults to fluid injection and perform a series of sensitivity tests considering: (1) permeability of the fault zone, (2) locations and the number of faults with respect to the injection point, and (3) well operations with varying the injection rate. Our analysis of the Coulomb stress change suggests that the sealing fault confines pressure diffusion which stabilizes or weakens the nearby conductive fault depending on the injection location. We perform the sensitivity test by changing injection scenarios (time-dependent rates), while keeping the total amount of injected fluids. Sensitivity analysis shows that gradual reduction of the injection rate minimizes the Coulomb stress change and the least seismicity rates are predicted. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.

  3. Nonlinear modeling and testing of magneto-rheological fluids in low shear rate squeezing flows

    International Nuclear Information System (INIS)

    Farjoud, Alireza; Ahmadian, Mehdi; Craft, Michael; Mahmoodi, Nima; Zhang, Xinjie

    2011-01-01

    A novel analytical investigation of magneto-rheological (MR) fluids in squeezing flows is performed and the results are validated with experimental test data. The squeeze flow of MR fluids has recently been of great interest to researchers. This is due to the large force capacity of MR fluids in squeeze mode compared to other modes (valve and shear modes), which makes the squeeze mode appropriate for a wide variety of applications such as impact dampers and engine mounts. Tested MR fluids were capable of providing a large range of controllable force along a short stroke in squeeze mode. A mathematical model was developed using perturbation techniques to predict closed-form solutions for velocity field, shear rate distribution, pressure distribution and squeeze force. Therefore, the obtained solutions greatly help with the design process of intelligent devices that use MR fluids in squeeze mode. The mathematical model also reduces the need for complicated and computationally expensive numerical simulations. The analytical results are validated by performing experimental tests on a novel MR device called an 'MR pouch' in an MR squeeze mode rheometer, both designed and built at CVeSS

  4. SEASONAL VARIATIONS IN HUMAN PAROTID FLUID FLOW RATE IN A SUBTROPICAL CLIMATE.

    Science.gov (United States)

    Parotid fluid was collected under conditions of very minimal stimulation from 3,868 systemically healthy young adult males over a period of two...calendar years. The study was carried out in a subtropical climate in which the only thermal discomfort resulted from the summer heat. Parotid flow rate...fall. During the summer months the mean rate of parotid flow was 0.031 ml./minute; during the winter the flow rate mean increased by 35% to 0.042 ml

  5. Flow Rates in Liquid Chromatography, Gas Chromatography and Supercritical Fluid Chromatography: A Tool for Optimization

    Directory of Open Access Journals (Sweden)

    Joris Meurs

    2016-08-01

    Full Text Available This paper aimed to develop a standalone application for optimizing flow rates in liquid chromatography (LC, gas chromatography (GC and supercritical fluid chromatography (SFC. To do so, Van Deemter’s equation, Knox’ equation and Golay’s equation were implemented in a MATLAB script and subsequently a graphical user interface (GUI was created. The application will show the optimal flow rate or linear velocity and the corresponding plate height for the set input parameters. Furthermore, a plot will be shown in which the plate height is plotted against the linear flow velocity. Hence, this application will give optimized flow rates for any set conditions with minimal effort.

  6. Influence of fluid properties, flow rate and aspect ratios on stratification in a cylindrical cavity

    International Nuclear Information System (INIS)

    Bouhdjar, A.; Benyoucef, B.; Harhad, A.

    2005-01-01

    Fluid flow and temperature field in a cavity are numerically simulated using finite volume techniques. The fluid flow in the vertical cylindrical cavity is assumed to be two-dimensional. Inflow occurs at the top through a ring like entrance and outflow takes place at the bottom through an exit of the same shape. The study considers a transient mixed convection flow. The governing equations are the conservation equations for laminar natural convection flow based on the Boussinesq approximation. Forced convection flow is superimposed through the appropriate boundary conditions (inflow and outflow conditions). The influence of the mass flow rate and of the fluid is made through the Reynolds number and the Prandtl number. Stratification analysis is made qualitatively through temperature distribution. In a previous study, consideration was given to low Reynolds numbers i.e. Re +4 ) in considering water (Pr=3.01) as the working fluid for the thermal energy storage. Correlations for the storage efficiency are deduced with respect to the Reynolds number and cavity aspect ratios of 1/0.5, 1/1 and 1/2. So the objective of the work is to get more information on the influence of flow rate on the storage efficiency as well as on the medium mean temperature. (author)

  7. Influence of fluid properties, flow rate and aspect ratios on stratification in a cylindrical cavity

    International Nuclear Information System (INIS)

    Bouhdjar, A.; Harhad, A.; Guerri, O.

    2003-01-01

    The fluid flow and temperature field in a cavity are numerically simulated using finite volume techniques. The fluid flow in the vertical cylindrical cavity is assumed to be two-dimensional. Inflow occurs at the top through a ring like entrance and outflow takes place at the bottom through an exit of the same shape. The study considers a transient mixed convection flow. The governing equations are the conservation equations for laminar natural convection flow based on the Boussinesq approximation. Forced convection flow is superimposed through the appropriate boundary conditions (inflow and outflow conditions). The influence of the mass flow rate and of the fluid is made through the Reynolds number and the Prandtl number. Stratification analysis is made qualitatively through temperature distribution. The study considers two fluids i.e. water (Pr=4.5) and ethylene glycol (Pr=51) and cavity aspect ratios of 1/0.5 and 1 /2. So the objective of the work is to get more information on the influence of flow rate on the performance of the thermal energy storage. Correlations for the storage efficiency are deduced with respect to the Reynolds number. (author)

  8. Perfusion CT in acute stroke

    International Nuclear Information System (INIS)

    Eckert, Bernd; Roether, Joachim; Fiehler, Jens; Thomalla, Goetz

    2015-01-01

    Modern multislice CT scanners enable multimodal protocols including non-enhanced CT, CT angiography, and CT perfusion. A 64-slice CT scanner provides 4-cm coverage. To cover the whole brain, a 128 - 256-slice scanner is needed. The use of perfusion CT requires an optimized scan protocol in order to reduce exposure to radiation. As compared to non-enhanced CT and CT angiography, the use of CT perfusion increases detection rates of cerebral ischemia, especially small cortical ischemic lesions, while the detection of lacunar and infratentorial stroke lesions remains limited. Perfusion CT enables estimation of collateral flow in acute occlusion of large intra- or extracranial arteries. Currently, no established reliable thresholds are available for determining infarct core and penumbral tissue by CT perfusion. Moreover, perfusion parameters depend on the processing algorithms and the software used for calculation. However, a number of studies point towards a reduction of cerebral blood volume (CBV) below 2 ml/100 g as a critical threshold that identifies infarct core. Large CBV lesions are associated with poor outcome even in the context of recanalization. The extent of early ischemic signs on non-enhanced CT remains the main parameter from CT imaging to guide acute reperfusion treatment. Nevertheless, perfusion CT increases diagnostic and therapeutic certainty in the acute setting. Similar to stroke MRI, perfusion CT enables the identification of tissue at risk of infarction by the mismatch between infarct core and the larger area of critical hypoperfusion. Further insights into the validity of perfusion parameters are expected from ongoing trials of mechanical thrombectomy in stroke.

  9. Quality assessment of a placental perfusion protocol

    DEFF Research Database (Denmark)

    Mathiesen, Line; Mose, Tina; Mørck, Thit Juul

    2010-01-01

    mlh(-1) from the fetal reservoir) when adding 2 (n=7) and 20mg (n=9) FITC-dextran/100ml fetal perfusion media. Success rate of the Copenhagen placental perfusions is provided in this study, including considerations and quality control parameters. Three checkpoints suggested to determine success rate...

  10. Influence of Reduced Mass Flow Rate and Chamber Backpressure on Swirl Injector Fluid Mechanics

    Science.gov (United States)

    Kenny, R Jeremy; Hulka, James R.

    2008-01-01

    Industry interest in variable-thrust liquid rocket engines places a demand on engine injector technology to operate over a wide range of liquid mass flow rates and chamber backpressures. One injection technology of current interest for variable thrust applications is an injector design with swirled fluids. Current swirl injector design methodologies do not take into account how swirl injector design parameters respond to elevated chamber backpressures at less than design mass flow rates. The current work was created to improve state-of-the-art swirl injector design methods in this area. The specific objective was to study the effects of elevated chamber backpressure and off-design mass flow rates on swirl injector fluid mechanics. Using a backpressure chamber with optical access, water was flowed through a swirl injector at various combinations of chamber backpressure and mass flow rates. The film thickness profile down the swirl injector nozzle section was measured through a transparent nozzle section of the injector. High speed video showed measurable increases in the film thickness profile with application of chamber backpressure and mass flow rates less than design. At prescribed combinations of chamber backpressure and injected mass flow rate, a discrete change in the film thickness profile was observed. Measured injector discharge coefficient values showed different trends with increasing chamber backpressure at low mass flow rates as opposed to near-design mass flow rates. Downstream spray angles showed classic changes in morphology as the mass flow rate was decreased below the design value. Increasing chamber backpressure decreased the spray angle at any injection mass flow rate. Experimental measurements and discussion of these results are reported in this paper.

  11. Assessments of fluid friction factors for use in leak rate calculations

    Energy Technology Data Exchange (ETDEWEB)

    Chivers, T.C. [Berkeley Technology Centre, Glos (United Kingdom)

    1997-04-01

    Leak before Break procedures require estimates of leakage, and these in turn need fluid friction to be assessed. In this paper available data on flow rates through idealized and real crack geometries are reviewed in terms of a single friction factor k It is shown that for {lambda} < 1 flow rates can be bounded using correlations in terms of surface R{sub a} values. For {lambda} > 1 the database is less precise, but {lambda} {approx} 4 is an upper bound, hence in this region flow calculations can be assessed using 1 < {lambda} < 4.

  12. Device for measuring the flow rate of a fluid moving through a pipe

    International Nuclear Information System (INIS)

    Barge, Gilles; Bouchard, Patrick; Chaix, J.E.; Rigaud, J.L.; Vivaldi, Andre.

    1981-01-01

    A device is described for measuring the flow rate, in particular through large section pipes, such as those found in water type nuclear reactors, thermal power stations and gas loops. This device includes a plate drilled with holes crossed by a fluid and held in the pipe by deformable components on which are secured strain gauges forming the detecting element of an electronic device for processing the signal emitted by the gauges. This device can be employed, for instance, for measuring the flow rate of a coolant in the primary system of a nuclear reactor [fr

  13. The effect of ascitic fluid hydrostatic pressure on albumin extravasation rate in patients with cirrhosis of the liver

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Parving, H H; Lassen, N A

    1981-01-01

    and pigs with posthepatic portal hypertension and intraperitoneally instilled fluid were studied before and after abdominal paracentesis in order to evaluate the effect of ascitic fluid hydrostatic pressure on the transvascular escape rate of albumin. TERalb of the ascitic patients (n = 6) were on average......, TERalb rose significantly to an average of 24.3% IVMalb.h-1. The increased albumin extravasation rate after removal of ascites is best explained by an increased sinusoidal-tissue pressure difference caused by a decreased hydrostatic fluid pressure in the liver interstitium (portal and subcapsular spaces......) due to the hydrostatic effect of the removed ascitic fluid....

  14. Regional cerebral metabolic rate for glucose and cerebrospinal fluid monoamine metabolites in subacute sclerosing panencephalitis

    International Nuclear Information System (INIS)

    Yanai, Kazuhiko; Miyabayashi, Shigeaki; Iinuma, Kazuie; Tada, Keiya; Fukuda, Hiroshi; Ito, Masatoshi; Matsuzawa, Taiju.

    1987-01-01

    Regional cerebral metabolic rate for glucose (rCMRglu) and cerebrospinal fluid monoamine metabolites were measured in two cases of subacute sclerosing panencephalitis (SSPE) with different clinical courses. A marked decrease in rCMRglu was found in the cortical gray matter of a patient with rapidly developing SSPE (3.6 - 4.2 mg/100 g brain tissue/min). However, the rCMRglu was preserved in the caudate and lenticular nuclei of the patient (7.7 mg/100 g/min). The rCMRglu in a patient with slowly developing SSPE revealed patterns and values similar to those of the control. Cerebrospinal fluid monoamine metabolites ; homovanilic acid and 5-hydroxyindoleacetic acid, were decreased in both rapidly and slowly developing SSPE. These data indicated that rCMRglu correlated better with the neurological and psychological status and that dopaminergic and serotonergic abnormalities have been implicated in pathophysiology of SSPE. (author)

  15. A randomized, double-blinded, controlled trial of the effects of fluid rate and/or presence of dextrose in intravenous fluids on the labor course of nulliparas.

    Science.gov (United States)

    Fong, Alex; Serra, Allison E; Caballero, Deysi; Garite, Thomas J; Shrivastava, Vineet K

    2017-08-01

    Prolonged labor has been demonstrated to increase adverse maternal and neonatal outcome. A practice that may decrease the risk of prolonged labor is the modification of fluid intake during labor. Several studies demonstrated that increased hydration in labor as well as addition of dextrose-containing fluids may be associated with a decrease in length of labor. The purpose of our study was to characterize whether high-dose intravenous fluids, standard-dose fluids with dextrose, or high-dose fluids with dextrose show a difference in the duration of labor in nulliparas. Nulliparous subjects with singletons who presented in active labor were randomized to 1 of 3 groups of intravenous fluids: 250 mL/h of normal saline, 125 mL/h of 5% dextrose in normal saline, or 250 mL/h of 2.5% dextrose in normal saline. The primary outcome was total length of labor from initiation of intravenous fluid in vaginally delivered subjects. Secondary outcomes included cesarean delivery rate and length of second stage of labor, among other maternal and neonatal outcomes. In all, 274 subjects who met inclusion criteria were enrolled. There were no differences in baseline characteristics among the 3 groups. There was no difference in the primary outcome of total length of labor in vaginally delivered subjects among the 3 groups. First stage of labor duration, second stage of labor duration, and cesarean delivery rates were also equivalent. There were no differences identified in other secondary outcomes including clinical chorioamnionitis, postpartum hemorrhage, blood loss, Apgar scores, or neonatal intensive care admission. There is no difference in length of labor or delivery outcomes when comparing high-dose intravenous fluids, addition of dextrose, or use of high-dose intravenous fluids with dextrose in nulliparous women who present in active labor. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Space-Time Dependent Transport, Activation, and Dose Rates for Radioactivated Fluids.

    Science.gov (United States)

    Gavazza, Sergio

    Two methods are developed to calculate the space - and time-dependent mass transport of radionuclides, their production and decay, and the associated dose rates generated from the radioactivated fluids flowing through pipes. The work couples space- and time-dependent phenomena, treated as only space- or time-dependent in the open literature. The transport and activation methodology (TAM) is used to numerically calculate space- and time-dependent transport and activation of radionuclides in fluids flowing through pipes exposed to radiation fields, and volumetric radioactive sources created by radionuclide motions. The computer program Radionuclide Activation and Transport in Pipe (RNATPA1) performs the numerical calculations required in TAM. The gamma ray dose methodology (GAM) is used to numerically calculate space- and time-dependent gamma ray dose equivalent rates from the volumetric radioactive sources determined by TAM. The computer program Gamma Ray Dose Equivalent Rate (GRDOSER) performs the numerical calculations required in GAM. The scope of conditions considered by TAM and GAM herein include (a) laminar flow in straight pipe, (b)recirculating flow schemes, (c) time-independent fluid velocity distributions, (d) space-dependent monoenergetic neutron flux distribution, (e) space- and time-dependent activation process of a single parent nuclide and transport and decay of a single daughter radionuclide, and (f) assessment of space- and time-dependent gamma ray dose rates, outside the pipe, generated by the space- and time-dependent source term distributions inside of it. The methodologies, however, can be easily extended to include all the situations of interest for solving the phenomena addressed in this dissertation. A comparison is made from results obtained by the described calculational procedures with analytical expressions. The physics of the problems addressed by the new technique and the increased accuracy versus non -space and time-dependent methods

  17. Preliminary rate expressions for analysis of radionuclide migration resulting from fluid flow through jointed media

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, K.L.

    1979-01-01

    A theoretical and experimental basis is being developed for analysis of radionuclide transport in jointed geologic media. Batch equilibration and rate experiments involving samples of Eleana argillite and tertiary silicic tuffs in contact with solutions containing Cs, Sr, or Pm indicated that most radionuclide sorption was associated with the surfaces of very small intergranular regions and that the rate of sorption was controlled by diffusion of the nuclides into such regions. Based on these experimental results, the continuity equations for radionuclides in the mobile and immobile phases were reduced to a model analogous to Rosen's equations for packed beds and were solved similarly. Using the model and experimental data, limited radionuclide transport analyses were made which indicated that important parameters controlling transport include the intergranular porosity and nuclide penetration depth, fracture plate spacing and length, fluid velocity and sorption distribution coefficient. Many of these parameters represent physical quantities or processes which can be quantified in the laboratory. However, fluid velocities and fracture plate spacings and lengths must be obtained from the field, and methods must be developed to establish reliable bounds for such field-determined parameters.

  18. Preliminary rate expressions for analysis of radionuclide migration resulting from fluid flow through jointed media

    International Nuclear Information System (INIS)

    Erickson, K.L.

    1979-01-01

    A theoretical and experimental basis is being developed for analysis of radionuclide transport in jointed geologic media. Batch equilibration and rate experiments involving samples of Eleana argillite and tertiary silicic tuffs in contact with solutions containing Cs, Sr, or Pm indicated that most radionuclide sorption was associated with the surfaces of very small intergranular regions and that the rate of sorption was controlled by diffusion of the nuclides into such regions. Based on these experimental results, the continuity equations for radionuclides in the mobile and immobile phases were reduced to a model analogous to Rosen's equations for packed beds and were solved similarly. Using the model and experimental data, limited radionuclide transport analyses were made which indicated that important parameters controlling transport include the intergranular porosity and nuclide penetration depth, fracture plate spacing and length, fluid velocity and sorption distribution coefficient. Many of these parameters represent physical quantities or processes which can be quantified in the laboratory. However, fluid velocities and fracture plate spacings and lengths must be obtained from the field, and methods must be developed to establish reliable bounds for such field-determined parameters

  19. Efficient Simulation of Compressible, Viscous Fluids using Multi-rate Time Integration

    Science.gov (United States)

    Mikida, Cory; Kloeckner, Andreas; Bodony, Daniel

    2017-11-01

    In the numerical simulation of problems of compressible, viscous fluids with single-rate time integrators, the global timestep used is limited to that of the finest mesh point or fastest physical process. This talk discusses the application of multi-rate Adams-Bashforth (MRAB) integrators to an overset mesh framework to solve compressible viscous fluid problems of varying scale with improved efficiency, with emphasis on the strategy of timescale separation and the application of the resulting numerical method to two sample problems: subsonic viscous flow over a cylinder and a viscous jet in crossflow. The results presented indicate the numerical efficacy of MRAB integrators, outline a number of outstanding code challenges, demonstrate the expected reduction in time enabled by MRAB, and emphasize the need for proper load balancing through spatial decomposition in order for parallel runs to achieve the predicted time-saving benefit. This material is based in part upon work supported by the Department of Energy, National Nuclear Security Administration, under Award Number DE-NA0002374.

  20. Near Wellbore Hydraulic Fracture Propagation from Perforations in Tight Rocks: The Roles of Fracturing Fluid Viscosity and Injection Rate

    Directory of Open Access Journals (Sweden)

    Seyed Hassan Fallahzadeh

    2017-03-01

    Full Text Available Hydraulic fracture initiation and near wellbore propagation is governed by complex failure mechanisms, especially in cased perforated wellbores. Various parameters affect such mechanisms, including fracturing fluid viscosity and injection rate. In this study, three different fracturing fluids with viscosities ranging from 20 to 600 Pa.s were used to investigate the effects of varying fracturing fluid viscosities and fluid injection rates on the fracturing mechanisms. Hydraulic fracturing tests were conducted in cased perforated boreholes made in tight 150 mm synthetic cubic samples. A true tri-axial stress cell was used to simulate real far field stress conditions. In addition, dimensional analyses were performed to correspond the results of lab experiments to field-scale operations. The results indicated that by increasing the fracturing fluid viscosity and injection rate, the fracturing energy increased, and consequently, higher fracturing pressures were observed. However, when the fracturing energy was transferred to a borehole at a faster rate, the fracture initiation angle also increased. This resulted in more curved fracture planes. Accordingly, a new parameter, called fracturing power, was introduced to relate fracture geometry to fluid viscosity and injection rate. Furthermore, it was observed that the presence of casing in the wellbore impacted the stress distribution around the casing in such a way that the fracture propagation deviated from the wellbore vicinity.

  1. Effects of fluid overload on heart rate variability in chronic kidney disease patients on hemodialysis.

    Science.gov (United States)

    Ferrario, Manuela; Moissl, Ulrich; Garzotto, Francesco; Cruz, Dinna N; Clementi, Anna; Brendolan, Alessandra; Tetta, Ciro; Gatti, Emanuele; Signorini, Maria G; Cerutti, Sergio; Ronco, Claudio

    2014-02-04

    While fluid overload (FO) and alterations in the autonomic nervous system (ANS) such as hypersympathetic activity, are known risk factors for cardiovascular morbidity and mortality in patients on chronic hemodialysis (HD), their relationship has not been thoroughly studied. In this observational study involving 69 patients on chronic HD, FO was assessed by whole body bioimpedance measurements before the midweek HD session and ANS activity reflected by Heart Rate Variability (HRV) was measured using 24-hour Holter electrocardiogram recordings starting before the same HD treatment. In total, 13 different HRV indices were analyzed, comprising a mixture of time domain, frequency domain and complexity parameters. A correlation analysis was performed between the HRV indices and hydration status indices. Successively, patients were retrospectively assigned to a high FO (H, FO > 2.5 L) or low FO (L, FO ≤ 2.5 L) group and these were further compared also after stratification by diabetes mellitus. Finally, a small number of patients without diabetes with significant and persistent FO were followed up for 3 months post-study to investigate how normalization of fluid status affects HRV. SDANN, VLF, LZC and HF% parameters significantly correlate with FO (correlation coefficients were respectively r = -0.40, r = -0.37, r = -0.28 and r = 0.26, p-value hydration status (correlation coefficients were respectively r = -0.31 and r = -0.33, p-value hydration status is accompanied by improved HRV.

  2. The Effect of Feed to Inoculums Ratio on Biogas Production Rate from Cattle Manure Using Rumen Fluid as Inoculums

    Directory of Open Access Journals (Sweden)

    S. Sunarso

    2010-12-01

    Full Text Available In this study, rumen fluid of animal ruminant was used as inoculums to increase biogas production rate from cattle manure at mesophilic condition. A series of laboratory experiments using 400 ml biodigester were performed in batch operation mode. Given 100 grams of fresh cattle manure was fed to each biodigester and mixed with rumen fluid and tap water resulting five different feed to inoculum (F/I ratios (i.e. 17.64, 23.51, 35.27, and 70.54. The operating temperatures were varied at room temperature. The results showed that the rumen fluid inoculated to biodigester significantly effected the biogas production. Rumen fluid inoculums caused biogas production rate and efficiency increase more than two times in compare to manure substrate without rumen fluid inoculums. At four F/Is tested, after 80 days digestion, the biogas yield were 191, 162, 144 and 112 mL/g VS, respectively. About 80% of the biogas production was obtained during the first 40 days of digestion. The best performance of biogas production will be obtained if F/I ratio is in the range of 17.64 to 35.27 (correspond to 25 – 50 % of rumen fluid. The future work will be carried out to study the dynamics of biogas production if both the rumen fluid inoculums and manure are fed in the continuous system

  3. Evaluation of fluid intake, weight loss and sweat rate in young triathletes

    Directory of Open Access Journals (Sweden)

    María Cristina Sellés López de Castro

    2015-10-01

    Full Text Available Introduction: Triathlon is an endurance sport comprising three disciplines: swimming, cycling and running. It is necessary to purpose guidelines in order to avoid dehydration during training or competition and keep good hydration before, during and after physical activity. The aim of this study is to evaluation of fluid intake, weight loss and sweat rate in young triathletes, during different trainings.Material and Methods: A descriptive-observational study in 14 triathletes (7 boys and 7 girls during a session of swimming, other session of cycling, another session of running. Fluid intake, weight loss, % of total body water, % dehydration and sweat rate, were assessed. Triathletes drank water in their drums of 750 ml and urine measurement was performed in containers.Results: The results of our study following the next order: swimming, cycling and running. Water intake 2.66±1.94ml/min, 7.91±7.69ml/min y 7.08±4.13ml/min in boys and 3.43±1.53ml/min, 6.39±5.36ml/min y 8.33±2.74ml/min in girls; weight loss 0.83±0.5kg, 0.47±0.3kg y 0.98±0.4kg in boys and 0.79±0.3kg, 0.47±0.58kg y 0.28±0.21kg in girls; and sweating rate 4.44±4.9ml/ min, 11.81±6.46ml/min y 5.29±3.13ml/min in boys and 3.89±2.4ml/min, 4.69±4.20ml/min and 7.96±5.06ml/min in girls.Conclusions: The percentage of body water and dehydration, loss of weight and sweat rate were compared with other studies and it´s shown that our results are lower than others studies, being below the recommendations of liquid intake in athletes.

  4. Clinical application of cerebral dynamic perfusion studies

    International Nuclear Information System (INIS)

    DeLand, F.H.

    1975-01-01

    Radionuclide cerebral perfusion studies are assuming a far greater importance in the detection and differential diagnosis of cerebral lesions. Perfusion studies not only contribute to the differential diagnosis of lesions but in certain cases are the preferred methods by which more accurate clinical interpretations can be made. The characteristic blood flow of arterio-venous malformations readily differentiates this lesion from neoplasms. The decreased perfusion or absent perfusion observed in cerebral infarctions is diagnostic without concurrent evidence from static images. Changes in rates and direction of blood flow contribute fundamental information to the status of stenosis and vascular occlusion and, in addition, offer valuable information on the competency and routes of collateral circulation. The degree of cerebral perfusion after cerebral vascular accidents appears to be directly related to patient recovery, particularly muscular function. Cerebral perfusion adds a new parameter in the diagnosis of subdural haematomas and concussion and in the differentiation of obscuring radioactivity from superficial trauma. Although pictorial displays of perfusion blood flow will offer information in most cerebral vascular problems, the addition of computer analysis better defines temporal relationships of regional blood flow, quantitative changes in flow and the detection of the more subtle increases or decreases in cerebral blood flow. The status of radionuclide cerebral perfusion studies has taken on an importance making it the primary modality for the diagnosis of cerebral lesions. (author)

  5. Effect of reference conditions on flow rate, modifier fraction and retention in supercritical fluid chromatography.

    Science.gov (United States)

    De Pauw, Ruben; Shoykhet Choikhet, Konstantin; Desmet, Gert; Broeckhoven, Ken

    2016-08-12

    When using compressible mobile phases such as fluidic CO2, the density, the volumetric flow rates and volumetric fractions are pressure dependent. The pressure and temperature definition of these volumetric parameters (referred to as the reference conditions) may alter between systems, manufacturers and operating conditions. A supercritical fluid chromatography system was modified to operate in two modes with different definition of the eluent delivery parameters, referred to as fixed and variable mode. For the variable mode, the volumetric parameters are defined with reference to the pump operating pressure and actual pump head temperature. These conditions may vary when, e.g. changing the column length, permeability, flow rate, etc. and are thus variable reference conditions. For the fixed mode, the reference conditions were set at 150bar and 30°C, resulting in a mass flow rate and mass fraction of modifier definition which is independent of the operation conditions. For the variable mode, the mass flow rate of carbon dioxide increases with system pump operating pressure, decreasing the fraction of modifier. Comparing the void times and retention factor shows that the deviation between the two modes is almost independent of modifier percentage, but depends on the operating pressure. Recalculating the set volumetric fraction of modifier to the mass fraction results in the same retention behaviour for both modes. This shows that retention in SFC can be best modelled using the mass fraction of modifier. The fixed mode also simplifies method scaling as it only requires matching average column pressure. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Does amnioinfusion reduce caesarean section rate in meconium-stained amniotic fluid.

    Science.gov (United States)

    Choudhary, Deepti; Bano, Imam; Ali, S M

    2010-07-01

    The purpose of our study was to evaluate the safety and efficacy of transcervical amnioinfusion during labour complicated by meconium-stained amniotic fluid, in a setting with limited peripartum facilities, to lower the incidence of caesarean section. A prospective study was conducted in a teaching hospital in north India, which enrolled 292 patients admitted in labour. Patients were randomly divided into two groups after taking their consent. One group received transcervical amnioinfusion, whilst in the other group amnioinfusion was not done. Caesarean sections were performed in either group if there were foetal heart rate abnormalities (bradycardia or irregularity for 10-20 min) or slow progress of labour. The outcomes studied were the incidence of caesarean sections, duration of maternal hospital stay, maternal febrile morbidity (temperature of >38 degrees C, 24 h after delivery), low Apgar score (at 1 and 5 min), respiratory death, MAS and perinatal mortality. There was a statistically significant reduction in the incidence of caesarean sections in the study group compared to the control group (31 vs. 61%). Amnioinfusion was associated with improved neonatal outcome as evidenced by statistically improved Apgar score at 1 min in newborns in the study group compared to the control group (10 vs. 37.2%). Amnioinfusion during labour was not associated with any significant maternal and neonatal complications. The mean hospital stay of the mother was decreased significantly in the study group patients compared to the control group. Transcervical amnioinfusion in labour for meconium-stained amniotic fluid is a simple, safe and easy-to-perform procedure. It can be performed safely in a setup with limited peripartum facilities, especially in developing countries, to decrease intrapartum operative intervention and reduce foetomaternal morbidity and mortality.

  7. Assessment of drug disposition in the perfused rat brain by statistical moment analysis

    International Nuclear Information System (INIS)

    Sakane, T.; Nakatsu, M.; Yamamoto, A.; Hashida, M.; Sezaki, H.; Yamashita, S.; Nadai, T.

    1991-01-01

    Drug disposition in the brain was investigated by statistical moment analysis using an improved in situ brain perfusion technique. The right cerebral hemisphere of the rat was perfused in situ. The drug and inulin were injected into the right internal carotid artery as a rapid bolus and the venous outflow curve at the posterior facial vein was obtained. The infusion rate was adjusted to minimize the flow of perfusion fluid into the left hemisphere. The obtained disposition parameters were characteristics and considered to reflect the physicochemical properties of each drug. Antipyrine showed a small degree of initial uptake. Therefore, its apparent distribution volume (Vi) and apparent intrinsic clearance (CLint,i) were small. Diazepam showed large degrees of both influx and efflux and, thus, a large Vi. Water showed parameters intermediate between those of antipyrine and those of diazepam. Imipramine, desipramine, and propranolol showed a large CLint,i compared with those of the other drugs. The extraction ratio of propranolol significantly decreased with increasing concentrations of unlabeled propranolol in the perfusion fluid. These findings may be explained partly by the tissue binding of these drugs. In conclusion, the present method is useful for studying drug disposition in the brain

  8. The effect of ascitic fluid hydrostatic pressure on albumin extravasation rate in patients with cirrhosis of the liver

    DEFF Research Database (Denmark)

    Henriksen, J H; Parving, H H; Christiansen, Lasse

    1981-01-01

    Overall transvascular escape rate of albumin [TERalb, i.e. the fraction of intravascular mass of albumin (IVMalb) passing to the extravascular space per unit time] was determined from the disappearance of i.v. injected radioiodinated serum albumin. Patients with tense ascites due to liver cirrhosis...... and pigs with posthepatic portal hypertension and intraperitoneally instilled fluid were studied before and after abdominal paracentesis in order to evaluate the effect of ascitic fluid hydrostatic pressure on the transvascular escape rate of albumin. TERalb of the ascitic patients (n = 6) were on average......, TERalb rose significantly to an average of 24.3% IVMalb.h-1. The increased albumin extravasation rate after removal of ascites is best explained by an increased sinusoidal-tissue pressure difference caused by a decreased hydrostatic fluid pressure in the liver interstitium (portal and subcapsular spaces...

  9. Aseismic and seismic slip induced by fluid injection from poroelastic and rate-state friction modeling

    Science.gov (United States)

    Liu, Y.; Deng, K.; Harrington, R. M.; Clerc, F.

    2016-12-01

    Solid matrix stress change and pore pressure diffusion caused by fluid injection has been postulated as key factors for inducing earthquakes and aseismic slip on pre-existing faults. In this study, we have developed a numerical model that simulates aseismic and seismic slip in a rate-and-state friction framework with poroelastic stress perturbations from multi-stage hydraulic fracturing scenarios. We apply the physics-based model to the 2013-2015 earthquake sequences near Fox Creek, Alberta, Canada, where three magnitude 4.5 earthquakes were potentially induced by nearby hydraulic fracturing activity. In particular, we use the relocated December 2013 seismicity sequence to approximate the fault orientation, and find the seismicity migration spatiotemporally correlate with the positive Coulomb stress changes calculated from the poroelastic model. When the poroelastic stress changes are introduced to the rate-state friction model, we find that slip on the fault evolves from aseismic to seismic in a manner similar to the onset of seismicity. For a 15-stage hydraulic fracturing that lasted for 10 days, modeled fault slip rate starts to accelerate after 3 days of fracking, and rapidly develops into a seismic event, which also temporally coincides with the onset of induced seismicity. The poroelastic stress perturbation and consequently fault slip rate continue to evolve and remain high for several weeks after hydraulic fracturing has stopped, which may explain the continued seismicity after shut-in. In a comparison numerical experiment, fault slip rate quickly decreases to the interseismic level when stress perturbations are instantaneously returned to zero at shut-in. Furthermore, when stress perturbations are removed just a few hours after the fault slip rate starts to accelerate (that is, hydraulic fracturing is shut down prematurely), only aseismic slip is observed in the model. Our preliminary results thus suggest the design of fracturing duration and flow

  10. Ventilation and perfusion display in a single image

    International Nuclear Information System (INIS)

    Lima, J.J.P. de; Botelho, M.F.R.; Pereira, A.M.S.; Rafael, J.A.S.; Pinto, A.J.; Marques, M.A.T.; Pereira, M.C.; Baganha, M.F.; Godinho, F.

    1991-01-01

    A new method of ventilation and perfusion display onto a single image is presented. From the data on regions of interest of the lungs, three-dimensional histograms are created, containing as parameters X and Y for the position of the pixels, Z for the perfusion and colour for local ventilation. The perfusion value is supplied by sets of curves having Z proportional to the local perfusion count rate. Ventilation modulates colour. Four perspective views of the histogram are simultaneously displayed to allow visualization of the entire organ. Information about the normal ranges for both ventilation and perfusion is also provided in the histograms. (orig.)

  11. Reduction of momentum transfer rates by parallel electric fields: A two-fluid demonstration

    International Nuclear Information System (INIS)

    Delamere, P.A.; Stenbaek-Nielsen, H.C.; Otto, A.

    2002-01-01

    Momentum transfer between an ionized gas cloud moving relative to an ambient magnetized plasma is a general problem in space plasma physics. Obvious examples include the Io-Jupiter interaction, comets, and coronal mass ejections. Active plasma experiments have demonstrated that momentum transfer rates associated with Alfven wave propagation are poorly understood. Barium injection experiments from the Combined Release and Radiation Effects Satellite (CRRES) have shown that dense ionized clouds are capable of ExB drifting over large distances perpendicular to the magnetic field. The CRRES 'skidding' distances were much larger than predicted by magnetohydrodynamic theory and it has been proposed that parallel electric fields were a key component in the skidding phenomenon. A two-fluid code was used to demonstrate the role of parallel electric fields in reducing momentum transfer between two distinct plasma populations. In this study, a dense plasma was initialized moving relative to an ambient plasma and perpendicular to B. Parallel electric fields were introduced via a friction term in the electron momentum equation and the collision frequency was scaled in proportion to the field-aligned current density. The simulation results showed that parallel electric fields decreased the decelerating magnetic tension force on the plasma cloud through a magnetic diffusion/reconnection process

  12. Dynamic contrast enhanced MRI for perfusion quantification

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke

    2002-01-01

    Magnetic resonance imaging, during bolus passage of a paramagnetic contrast agent, is used world-wide to obtain parameters that reflect the pathological state of tissue. Abnormal perfusion occurs in diseases such as stoke and tumour. Consequently, perfusion quantication could have signi cant...... clinical value both in diagnosis and treatment of such pathologies. One approach for perfusion quanti cation involves using the contrast mechanism that a ects the transverse relaxation rates of the magnetization, R2 or R 2 , since this provides the most pronounced effect. However, the linearity between...

  13. Application of high-frame-rate neutron radiography to fluid measurement

    International Nuclear Information System (INIS)

    Mishima, Kaichiro; Hibiki, Takashi

    1997-01-01

    To apply Neutron radiography (NR) technique to multiphase flow research, high frame-rate NR was developed by assembling up-to-date technologies for neutron source, scintillator, high-speed video and image intensifier. This imaging system has several advantages such as a long recording time (up to 21 minutes), high-frame-rate (up to 1000 frames/s) imaging and no need for triggering signal. Visualization studies of air-water two-phase flow in a metallic duct and molten metal-water interaction were performed at the recording speeds of 250, 500 and 1000 frames/s. The qualities of those consecutive images were good enough to observe the flow pattern and behavior. It was demonstrated also that some characteristics of two-phase flow could be measured from those images in collaboration with image processing techniques. By utilizing geometrical information extracted from NR images, data on flow regime, rising velocity of bubbles, and wave height and interfacial area in annular flow could be obtained. By utilizing attenuation characteristics of neutrons in materials, measurements of void profile and average void fraction could be performed. For this purpose, a quantification method, i.e. Σ-scaling method, was proposed based upon the consideration on the effect of scattered neutrons. This method was tested against known void profiles and compared with existing measurement methods and a correlation for void fraction. It was confirmed that this new technique has significant advantages both in visualizing and measuring high-speed fluid phenomena. (J.P.N.)

  14. Technical characterization of dialysis fluid flow and mass transfer rate in dialyzers with various filtration coefficients using dimensionless correlation equation.

    Science.gov (United States)

    Fukuda, Makoto; Yoshimura, Kengo; Namekawa, Koki; Sakai, Kiyotaka

    2017-06-01

    The objective of the present study is to evaluate the effect of filtration coefficient and internal filtration on dialysis fluid flow and mass transfer coefficient in dialyzers using dimensionless mass transfer correlation equations. Aqueous solution of vitamin B 12 clearances were obtained for REXEED-15L as a low flux dialyzer, and APS-15EA and APS-15UA as high flux dialyzers. All the other design specifications were identical for these dialyzers except for filtration coefficient. The overall mass transfer coefficient was calculated, moreover, the exponents of Reynolds number (Re) and film mass transfer coefficient of the dialysis-side fluid (k D ) for each flow rate were derived from the Wilson plot and dimensionless correlation equation. The exponents of Re were 0.4 for the low flux dialyzer whereas 0.5 for the high flux dialyzers. Dialysis fluid of the low flux dialyzer was close to laminar flow because of its low filtration coefficient. On the other hand, dialysis fluid of the high flux dialyzers was assumed to be orthogonal flow. Higher filtration coefficient was associated with higher k D influenced by mass transfer rate through diffusion and internal filtration. Higher filtration coefficient of dialyzers and internal filtration affect orthogonal flow of dialysis fluid.

  15. Method and Apparatus for Predicting Unsteady Pressure and Flow Rate Distribution in a Fluid Network

    Science.gov (United States)

    Majumdar, Alok K. (Inventor)

    2009-01-01

    A method and apparatus for analyzing steady state and transient flow in a complex fluid network, modeling phase changes, compressibility, mixture thermodynamics, external body forces such as gravity and centrifugal force and conjugate heat transfer. In some embodiments, a graphical user interface provides for the interactive development of a fluid network simulation having nodes and branches. In some embodiments, mass, energy, and specific conservation equations are solved at the nodes, and momentum conservation equations are solved in the branches. In some embodiments, contained herein are data objects for computing thermodynamic and thermophysical properties for fluids. In some embodiments, the systems of equations describing the fluid network are solved by a hybrid numerical method that is a combination of the Newton-Raphson and successive substitution methods.

  16. Perfusion dyssynchrony analysis

    NARCIS (Netherlands)

    Chiribiri, A.; Villa, A.D.M.; Sammut, E.; Breeuwer, M.; Nagel, E.

    2015-01-01

    AIMS: We sought to describe perfusion dyssynchrony analysis specifically to exploit the high temporal resolution of stress perfusion CMR. This novel approach detects differences in the temporal distribution of the wash-in of contrast agent across the left ventricular wall. METHODS AND RESULTS:

  17. Laser doppler perfusion imaging

    International Nuclear Information System (INIS)

    Waardell, K.

    1992-01-01

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

  18. Neurotensin releases norepinephrine differentially from perfused hypothalamus of sated and fasted rat

    International Nuclear Information System (INIS)

    Lee, T.F.; Rezvani, A.H.; Hepler, J.R.; Myers, R.D.

    1987-01-01

    The central injection of neurotensin (NT) has been reported to attenuate the intake of food in the fasted animal. To determine whether endogenous norepinephrine (NE) is involved in the satiating effect of NT, the in vivo activity of NE in circumscribed sites in the hypothalamus of the unanesthetized rat was examined. Bilateral guide tubes for push-pull perfusion were implanted stereotaxically to rest permanently above one of several intended sites of perfusion, which included the paraventricular nucleus (PVN), ventromedial nucleus (VMN), and the lateral hypothalamic (LH) area. After endogenous stores of NE at a specific hypothalamic locus were radiolabeled by microinjection of 0.02-0.5 μCi of [ 3 H]NE, an artificial cerebrospinal fluid was perfused at the site at a rate of 20 μl/min over successive intervals of 5.0 min. When 0.05 or 0.1 μg/μl NT was added to the perfusate, the peptide served either to enhance or educe the local release of NE at 50% of the sites of perfusion. In these experiments, the circumscribed effect of NT on the characteristics of catecholamine efflux depended entirely on the state of hunger or satiety of the rat. That is, when NT was perfused in the fully satiated rat, NE release was augmented within the PVn or VMN; conversely, NE release was inhibited in the LH. in the animal fasted for 18-22 h, NT exerted an opposite effect on the activity of NE within the same anatomical loci in that the efflux of NE was enhanced in the LH but attenuated or unaffected in the PVN or VMN. Taken together, these observations provide experimental support for the view-point that NT could act as a neuromodulator of the activity of hypothalamic noradrenergic neurons that are thought to play a functional role in the regulation of food intake

  19. Impact of irrigation flow rate and intrapericardial fluid on cooled-tip epicardial radiofrequency ablation.

    Science.gov (United States)

    Aryana, Arash; O'Neill, Padraig Gearoid; Pujara, Deep K; Singh, Steve K; Bowers, Mark R; Allen, Shelley L; d'Avila, André

    2016-08-01

    The optimal irrigation flow rate (IFR) during epicardial radiofrequency (RF) ablation has not been established. This study specifically examined the impact of IFR and intrapericardial fluid (IPF) accumulation during epicardial RF ablation. Altogether, 452 ex vivo RF applications (10 g for 60 seconds) delivered to the epicardial surface of bovine myocardium using 3 open-irrigated ablation catheters (ThermoCool SmartTouch, ThermoCool SmartTouch-SF, and FlexAbility) and 50 in vivo RF applications delivered (ThermoCool SmartTouch-SF) in 4 healthy adult swine in the presence or absence of IPF were examined. Ex vivo, RF was delivered at low (≤3 mL/min), reduced (5-7 mL/min), and high (≥10 mL/min) IFRs using intermediate (25-35 W) and high (35-45 W) power. In vivo, applications were delivered (at 9.3 ± 2.2 g for 60 seconds at 39 W) using reduced (5 mL/min) and high (15 mL/min) IFRs. Ex vivo, surface lesion diameter inversely correlated with IFR, whereas maximum lesion diameter and depth did not differ. While steam pops occurred more frequently at low IFR using high power (ThermoCool SmartTouch and ThermoCool SmartTouch-SF), tissue disruption was rare and did not vary with IFR. In vivo, charring/steam pop was not detected. Although there were no discernible differences in lesion size with IFR, surface lesion diameter, maximum diameter, depth, and volume were all smaller in the presence of IPF at both IFRs. Cooled-tip epicardial RF ablation created using reduced IFRs (5-7 mL/min) yields lesion sizes similar to those created using high IFRs (≥10 mL/min) without an increase in steam pop/tissue disruption, whereas the presence of IPF significantly reduces the lesion size. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  20. Safety actuator of the Cabri reactor as a function of its power and cooling fluid flow rate

    International Nuclear Information System (INIS)

    Bertrand, Jean; Da Costa Vieira, David; Tattegrain, Alain

    1969-04-01

    This report present a device which is to provide a stop command to the Cabri reactor when the rate of its power to the cooling fluid rate reaches a value determined with respect to water temperature in the circuit. The stop command is delivered by an actuator which opens a relay contact when the power reaches a specific value. The authors present the device, its characteristics, and principle. They also present the different amplifier circuits, the input and output circuits (flow rate input, temperature input, and output circuit), the energy supply, and the various adjustments

  1. Pulmonary perfusion ''without ventilation''

    International Nuclear Information System (INIS)

    Chapman, C.N.; Sziklas, J.J.; Spencer, R.P.; Rosenberg, R.J.

    1983-01-01

    An 88-yr-old man, with prior left upper lobectomy and phrenic nerve injury, had a ventilation/perfusion lung image. Both wash-in and equilibrium ventilation images showed no radioactive gas in the left lung. Nevertheless, the left lung was perfused. A similar result was obtained on a repeat study 8 days later. Delayed images, during washout, showed some radioactive gas in the left lung. Nearly absent ventilation (but continued perfusion) of that lung might have been related to altered gas dynamics brought about by the prior lobectomy, a submucosal bronchial lesion, phrenic nerve damage, and limited motion of the left part of the diaphragm. This case raises the issue of the degree of ventilation (and the phase relationship between the lungs) required for the entry of radioactive gas into a diseased lung, and the production of a ''reversed ventilation/perfusion mismatch.''

  2. Pelvic endometriosis with peritoneal fluid reduces pregnancy rates in women undergoing intrauterine insemination

    OpenAIRE

    Wu, Hong-Ming; Tzeng, Chii-Ruey; Chen, Chi-Hung; Chen, Pi-Hua

    2013-01-01

    Objective: This study investigated the occurrence of peritoneal fluid in women undergoing intrauterine insemination (IUI) and its correlation with the stage of pelvic endometriosis and its influence on pregnancy outcomes. Materials and Methods: A retrospective case–control design was used to recruit 272 infertile women with pelvic endometriosis. The treatment protocol consisted of controlled ovarian hyperstimulation with downregulation and gonadotropin for IUI treatment following ultrasoun...

  3. Continuous monitoring of fluid flow rate and contemporaneous biogeochemical fluxes in the sub-seafloor; the Mosquito flux meter

    Science.gov (United States)

    Culling, D. P.; Solomon, E. A.; Kastner, M.; Berg, R. D.

    2013-12-01

    Fluid flow through marine sediments and oceanic crust impacts seawater chemistry as well as diagenetic, thermal, seismic, and magmatic processes at plate boundaries, creates ore and gas hydrate deposits at and below seafloor, and establishes and maintains deep microbial ecosystems. However, steady-state fluid flow rates, as well as the temporal and spatial variability of fluid flow and composition are poorly constrained in many marine environments. A new, low-cost instrument deployable by ROV or submersible, named the Mosquito, was recently developed to provide continuous, long-term and campaign style monitoring of fluid flow rate and contemporaneous solute fluxes at multiple depths below the sea floor. The Mosquito consists of a frame that houses several osmotic pumps (Osmo-Samplers [OS]) connected to coils of tubing that terminate with an attachment to long thin titanium (Ti) needles, all of which are mounted to a release plate. The OS's consist of an acrylic housing which contains a brine chamber (BC) and a distilled water chamber (DWC) separated by semi permeable membranes. The osmotic gradient between the chambers drives the flow of distilled water into the BC. The DWC is connected to the Teflon tubing coil and a Ti needle, both of which are also filled with distilled water, thus the OS pulls fluid from the base of the needle through the tubing coil. One central Ti needle is attached to a custom-made tracer injection assembly, filled with a known volume of tracer, which is triggered, injecting a point source in the sediment. On a typical Mosquito, 4 needles are mounted vertically at varying depths with respect to the tracer injection needle, and 4 needles are mounted at equal depth but set at variable horizontal distances away from the tracer injection. Once the Mosquito has been placed on the seafloor, the release plate is manually triggered pushing the Ti needles into the sediment, then the tracer injection assembly is actuated. As the tracer is advected

  4. Ex-vivo machine perfusion for kidney preservation.

    Science.gov (United States)

    Hamar, Matyas; Selzner, Markus

    2018-06-01

    Machine perfusion is a novel strategy to decrease preservation injury, improve graft assessment, and increase organ acceptance for transplantation. This review summarizes the current advances in ex-vivo machine-based kidney preservation technologies over the last year. Ex-vivo perfusion technologies, such as hypothermic and normothermic machine perfusion and controlled oxygenated rewarming, have gained high interest in the field of organ preservation. Keeping kidney grafts functionally and metabolically active during the preservation period offers a unique chance for viability assessment, reconditioning, and organ repair. Normothermic ex-vivo kidney perfusion has been recently translated into clinical practice. Preclinical results suggest that prolonged warm perfusion appears superior than a brief end-ischemic reconditioning in terms of renal function and injury. An established standardized protocol for continuous warm perfusion is still not available for human grafts. Ex-vivo machine perfusion represents a superior organ preservation method over static cold storage. There is still an urgent need for the optimization of the perfusion fluid and machine technology and to identify the optimal indication in kidney transplantation. Recent research is focusing on graft assessment and therapeutic strategies.

  5. Hepatic arterial perfusion increases in the early stage of severe acute pancreatitis patients: Evaluation by perfusion computed tomography

    International Nuclear Information System (INIS)

    Koyasu, Sho; Isoda, Hiroyoshi; Tsuji, Yoshihisa; Yamamoto, Hiroshi; Matsueda, Kazuhiro; Watanabe, Yuji; Chiba, Tsutomu; Togashi, Kaori

    2012-01-01

    Purpose: Although hepatic perfusion abnormalities have been reported in patients with acute pancreatitis, hepatic perfusion with severe acute pancreatitis (SAP) has not been quantitatively evaluated in humans. Therefore, we investigated hepatic perfusion in patients with SAP using perfusion CT. Materials and methods: Hepatic perfusion CT was performed in 67 patients with SAP within 3 days after symptom onset. The patients were diagnosed as having SAP according to the Atlanta criteria. Fifteen cases were established as a control group. Perfusion CT was obtained for 54 s beginning with a bolus injection of 40 ml of contrast agent (600–630 mgI/kg) at a flow rate of 4 ml/s. Perfusion data were analyzed by the dual-input maximum slope method to obtain hepatic arterial perfusion (HAP) and hepatic portal perfusion (HPP). Finally, we compared HAP and HPP in SAP patients with those in the control group, respectively. Results: Average HAP was significantly higher in SAP patients than in the control group (75.1 ± 38.0 vs. 38.2 ± 9.0 ml/min/100 ml; p < 0.001). There was no significant difference in average HPP between SAP patients and the control group (206.7 ± 54.9 vs. 204.4 ± 38.5 ml/min/100 ml; p = 0.92). Conclusion: Using quantitative analysis on perfusion CT, we first demonstrated an increase of HAP in the right hepatic lobe in SAP patients.

  6. Modeling and design of optimal flow perfusion bioreactors for tissue engineering applications.

    Science.gov (United States)

    Hidalgo-Bastida, L Araida; Thirunavukkarasu, Sundaramoorthy; Griffiths, Sarah; Cartmell, Sarah H; Naire, Shailesh

    2012-04-01

    Perfusion bioreactors have been used in different tissue engineering applications because of their consistent distribution of nutrients and flow-induced shear stress within the tissue-engineering scaffold. A widely used configuration uses a scaffold with a circular cross-section enclosed within a cylindrical chamber and inlet and outlet pipes which are connected to the chamber on either side through which media is continuously circulated. However, fluid-flow experiments and simulations have shown that the majority of the flow perfuses through the center. This pattern creates stagnant zones in the peripheral regions as well as in those of high flow rate near the inlet and outlet. This non-uniformity of flow and shear stress, owing to a circular design, results in limited cell proliferation and differentiation in these areas. The focus of this communication is to design an optimized perfusion system using computational fluid dynamics as a mathematical tool to overcome the time-consuming trial and error experimental method. We compared the flow within a circular and a rectangular bioreactor system. Flow simulations within the rectangular bioreactor are shown to overcome the limitations in the circular design. This communication challenges the circular cross-section bioreactor configuration paradigm and provides proof of the advantages of the new design over the existing one. Copyright © 2011 Wiley Periodicals, Inc.

  7. The association between homocysteine in the follicular fluid with embryo quality and pregnancy rate in assisted reproductive techniques.

    Science.gov (United States)

    Ocal, Pelin; Ersoylu, Bilge; Cepni, Ismail; Guralp, Onur; Atakul, Nil; Irez, Tulay; Idil, Mehmet

    2012-04-01

    To investigate the association between follicular fluid homocysteine levels and embryo quality and pregnancy rates in patients undergoing assisted reproduction. Fifty infertile women who were admitted to our clinic were enrolled in the study. Ovulation induction was performed by using GnRH agonist and gonadotropins. For each patient, homocysteine level in the follicular fluid was measured by using nephelometric method after the oocyte pick-up. The association between the homocysteine concentration in the follicular fluid and the oocyte-embryo quality, pregnancy rates and hormone levels were investigated. Mean ± SD Hcy was 9.6 ± 2.02 μmol/L and 14.9 ± 2.93 μmol/L in pregnant and non-pregnant women, respectively (p Homocystein did not have any correlation with M2, late M2, and total number of oocytes, number of fertilized oocytes and transferred embryos, and embryo quality grade. Area under curve (AUC) of hcy for prediction of pregnancy failure was 0.922 (p = 0.0001, 95% Confidence interval 0.85-0.99). A threshold of 11.9 μmol/L of hcy had a sensitivity of 82%, specificity of 100%, positive predictive value of 100% and negative predictive value of 91.6% for prediction of pregnancy failure. The subgroup analysis in male factor infertility group (n = 28), showed that mean homocystein was 9.9 ± 2.44 μmol/L and 14.1 ± 2.72 μmol/L in pregnant and non-pregnant women, respectively (p = 0.002). Low follicular fluid homocysteine level is associated with a better chance of clinical pregnancy.

  8. Computational Fluid Dynamics (CFD) Modeling for High Rate Pulverized Coal Injection (PCI) to Blast Furnaces

    International Nuclear Information System (INIS)

    Zhou, Chenn

    2008-01-01

    Pulverized coal injection (PCI) into the blast furnace (BF) has been recognized as an effective way to decrease the coke and total energy consumption along with minimization of environmental impacts. However, increasing the amount of coal injected into the BF is currently limited by the lack of knowledge of some issues related to the process. It is therefore important to understand the complex physical and chemical phenomena in the PCI process. Due to the difficulty in attaining trus BF measurements, Computational fluid dynamics (CFD) modeling has been identified as a useful technology to provide such knowledge. CFD simulation is powerful for providing detailed information on flow properties and performing parametric studies for process design and optimization. In this project, comprehensive 3-D CFD models have been developed to simulate the PCI process under actual furnace conditions. These models provide raceway size and flow property distributions. The results have provided guidance for optimizing the PCI process

  9. Analysis of the influence of infeed rate and cutting fluid on cylindrical grinding processes using a conventional wheel

    Directory of Open Access Journals (Sweden)

    Bianchi Eduardo Carlos

    2004-01-01

    Full Text Available New worldwide trends such as globalization have rendered grinding processes increasingly important for industry, making it essential to perform in-depth studies of variations in grinding process parameters in the pursuit of greater cost effectiveness. This paper presents a comparative analysis of three different infeed rates, using a conventional grinding wheel on quenched and tempered D2 steel workpieces. Higher infeed rates are known to be correlated with shorter grinding times, rendering the process more economically attractive. Two different coolant fluids, 5% emulsion and pure oil, were used. The tests were carried out using the smallest possible amount of coolant and an optimized 5 mm diameter nozzle. The parameters analyzed were tangential force, specific energy, acoustic emission, roundness error and surface roughness. The surfaces of the workpieces were also examined by scanning electron microscopy (SEM. The results revealed that increased infeed rates could reduce processing times without compromising the quality of the workpiece profile, thereby reducing the cost of the process. The best cutting fluid, albeit more harmful to human health and less environmentally friendly, was found to be pure oil.

  10. Effect of Retarding Force on Mass Flow Rates of Fluid at Different ...

    African Journals Online (AJOL)

    ... mathematical model and software visualization to view the effect of retarding forces on the mass flow rate in term of visualization. C-sharp (C#) is the chosen program and this enable compares and us to determine the mass flow rates patterns in relation to retarding force in form of graphical tables at different temperature.

  11. Localization and Instability in Sheared Granular Materials: Role of Pore Fluids and Non-monotonic Rate Dependent Rheology

    Science.gov (United States)

    Ma, X.; Elbanna, A. E.; Kothari, K.

    2017-12-01

    Fault zone dynamics hold the key to resolving many outstanding geophysical problems including the heat flow paradox, discrepancy between fault static and dynamic strength, and energy partitioning. Most fault zones that generate tectonic events are gouge filled and fluid saturated posing the need for formulating gouge-specific constitutive models that capture spatially heterogeneous compaction and dilation, non-monotonic rate dependence, and transition between localized and distributed deformation. In this presentation, we focus primarily on elucidating microscopic underpinnings for shear banding and stick-slip instabilities in sheared saturated granular materials and explore their implications for earthquake dynamics. We use a non-equilibrium thermodynamics model, the Shear Transformation Zone theory, to investigate the dynamics of strain localization and its connection to stability of sliding in the presence and absence of pore fluids. We also consider the possible influence of self-induced mechanical vibrations as well as the role of external acoustic vibrations as analogue for triggering by a distant event. For the dry case, our results suggest that at low and intermediate strain rates, persistent shear bands develop only in the absence of vibrations. Vibrations tend to fluidize the granular network and de-localize slip at these rates. Stick-slip is only observed for rough grains and it is confined to the shear band. At high strain rates, stick-slip disappears and the different systems exhibit similar stress-slip response. Changing the vibration intensity, duration or time of application alters the system response and may cause long-lasting rheological changes. The presence of pore fluids modifies the stick slip pattern and may lead to both loss and development of slip instability depending on the value of the confining pressure, imposed strain rate and hydraulic parameters. We analyze these observations in terms of possible transitions between rate

  12. The growth of stem cells within {beta}-TCP scaffolds in a fluid-dynamic environment

    Energy Technology Data Exchange (ETDEWEB)

    Xu Shanglong [School of Mechatronics Engineering, University of Electronic Science and Technology, Chengdu (China); State Key Laboratory of Mechanical Manufacture System Engineering, Xi' an Jiaotong University, Xi' an (China); Li Dichen [State Key Laboratory of Mechanical Manufacture System Engineering, Xi' an Jiaotong University, Xi' an (China)], E-mail: dcli@mail.xjtu.edu.cn; Xie Youzhuan; Lu Jianxi; Dai Kerong [Department of Orthopaedic Surgery, Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China)

    2008-01-10

    A three-dimensional dynamic perfusion system was developed to provide mass transport and nutrient supply to permit the cell proliferation during the long-term culture inside a {beta}-tricalcium phosphate ({beta}-TCP) scaffold. Also the flow field throughout the scaffold was studied. The porous cylindrical scaffold with a central channel was seeded with the sheep mesenchymal stem cells (MSCs). Then the cell-seeded scaffolds were continuously perfused with the complete {alpha}-MEM medium by a peristaltic pump for 7, 14 and 28 days, respectively. Histological study showed that the cell proliferation rates were different throughout the whole scaffolds and the different cell coverage was shown in different positions of the scaffold. Unoccupied spaces were found in many macropores. A computational fluid dynamics (CFD) modeling was used to simulate the flow conditions within perfused cell-seeded scaffolds to give an insight into the mechanisms of these cell growth phenomena. Relating the simulation results to perfusion experiments, the even fluid velocity (approximately 0.52 mm/s) and shear stress (approximately 0.0055 Pa) were found to correspond to increased cell proliferation within the cell-scaffold constructs. Flow speeds were between 0.25 and 0.75 mm/s and shear stresses were between 0.003 and 0.008 Pa in approximately 75% of the regions. This method exhibits novel capabilities to compare the results obtained for different perfusion rates or different scaffold microarchitectures. It may allow specific fluid velocities and shear stresses to be determined to optimize the perfusion flow rate, porous scaffold architecture and distribution of in vitro tissue growth.

  13. The growth of stem cells within β-TCP scaffolds in a fluid-dynamic environment

    International Nuclear Information System (INIS)

    Xu Shanglong; Li Dichen; Xie Youzhuan; Lu Jianxi; Dai Kerong

    2008-01-01

    A three-dimensional dynamic perfusion system was developed to provide mass transport and nutrient supply to permit the cell proliferation during the long-term culture inside a β-tricalcium phosphate (β-TCP) scaffold. Also the flow field throughout the scaffold was studied. The porous cylindrical scaffold with a central channel was seeded with the sheep mesenchymal stem cells (MSCs). Then the cell-seeded scaffolds were continuously perfused with the complete α-MEM medium by a peristaltic pump for 7, 14 and 28 days, respectively. Histological study showed that the cell proliferation rates were different throughout the whole scaffolds and the different cell coverage was shown in different positions of the scaffold. Unoccupied spaces were found in many macropores. A computational fluid dynamics (CFD) modeling was used to simulate the flow conditions within perfused cell-seeded scaffolds to give an insight into the mechanisms of these cell growth phenomena. Relating the simulation results to perfusion experiments, the even fluid velocity (approximately 0.52 mm/s) and shear stress (approximately 0.0055 Pa) were found to correspond to increased cell proliferation within the cell-scaffold constructs. Flow speeds were between 0.25 and 0.75 mm/s and shear stresses were between 0.003 and 0.008 Pa in approximately 75% of the regions. This method exhibits novel capabilities to compare the results obtained for different perfusion rates or different scaffold microarchitectures. It may allow specific fluid velocities and shear stresses to be determined to optimize the perfusion flow rate, porous scaffold architecture and distribution of in vitro tissue growth

  14. Optimization of perfusion studies using Atropine

    International Nuclear Information System (INIS)

    Alvarado, A.N.; Valle, V.M.; Montoya, M.J.; Eskenazi, E.S.; Montiel, M.L.; Cueto, C.C.

    2002-01-01

    The studies of myocardial perfusion require an adequate stress; exercise or pharmacological. Every day, more pharmacological studies are performed, specially in some group of patients (women, AMI, etc). There some drugs that are used for this purpose, as adenosine and dobutamine. However, their cost and the lack of availability and infrastructure in our country do not allow there routinely use. We performed dipyridamol as a pharmacological stress, however in some patients there is a doubt regarding if the pharmacological effect was adequate. Atropine is a drug that is frequently used for different purpose and it is well know its tachycardic response. We present and alternative technique, using dipyridamol-atropine as a protocol of stress perfusion study. Our goal was to correlate the standard dipyridamol -thallium perfusion study and the dipyridamol -atropine-perfusion in patients with chronic coronary disease. We evaluated 6 patients (5 males) with stable angina and chronic coronary disease. A standard dipyridamol-thallium study was performed in all of them. Dipyridamole was administered intravenously at a rate of 0.14 mg/kg/min over 6 min for a total of 0.84 mg/kg body weight. Blood pressure, heart rate, EKG and symptoms were monitored before, during and after the pharmacological infusion. Two minutes after the infusion was completed, the radiotracer was injected intravenously. In the next 6 months, without any modification of the clinical situation (symptoms and therapy) a new dipyridamol study was performed, using 1 mg of atropine after the administration of dipyridamol. There were no differences in the collateral effects and we observed and average increase of 30% in the heart rate in relation with the study using dipyridamol alone. The addition of atropine to the standard dipyridamol perfusion study is safe, cheaper and improved the detection of perfusion defects in patients with coronary artery disease

  15. Flow-perfusion interferes with chondrogenic and hypertrophic matrix production by mesenchymal stem cells

    NARCIS (Netherlands)

    Kock, Linda M; Malda, Jos; Dhert, Wouter J A; Ito, Keita; Gawlitta, Debby

    2014-01-01

    Flow-perfusion is being promoted as a way to grow tissue-engineered cartilage in vitro. Yet, there is a concern that flow-perfusion may induce unwanted mechanical effects on chondrogenesis and terminal differentiation. Therefore, the aim of this study is to evaluate the effect of fluid flow on

  16. A Comprehensive Prediction Model of Hydraulic Extended-Reach Limit Considering the Allowable Range of Drilling Fluid Flow Rate in Horizontal Drilling.

    Science.gov (United States)

    Li, Xin; Gao, Deli; Chen, Xuyue

    2017-06-08

    Hydraulic extended-reach limit (HERL) model of horizontal extended-reach well (ERW) can predict the maximum measured depth (MMD) of the horizontal ERW. The HERL refers to the well's MMD when drilling fluid cannot be normally circulated by drilling pump. Previous model analyzed the following two constraint conditions, drilling pump rated pressure and rated power. However, effects of the allowable range of drilling fluid flow rate (Q min  ≤ Q ≤ Q max ) were not considered. In this study, three cases of HERL model are proposed according to the relationship between allowable range of drilling fluid flow rate and rated flow rate of drilling pump (Q r ). A horizontal ERW is analyzed to predict its HERL, especially its horizontal-section limit (L h ). Results show that when Q min  ≤ Q r  ≤ Q max (Case I), L h depends both on horizontal-section limit based on rated pump pressure (L h1 ) and horizontal-section limit based on rated pump power (L h2 ); when Q min  drilling fluid flow rate, while L h2 keeps decreasing as the drilling fluid flow rate increases. The comprehensive model provides a more accurate prediction on HERL.

  17. Reverse ventilation--perfusion mismatch

    International Nuclear Information System (INIS)

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients

  18. Flow rate impacts on capillary pressure and interface curvature of connected and disconnected fluid phases during multiphase flow in sandstone

    Science.gov (United States)

    Herring, Anna L.; Middleton, Jill; Walsh, Rick; Kingston, Andrew; Sheppard, Adrian

    2017-09-01

    We investigate capillary pressure-saturation (PC-S) relationships for drainage-imbibition experiments conducted with air (nonwetting phase) and brine (wetting phase) in Bentheimer sandstone cores. Three different flow rate conditions, ranging over three orders of magnitude, are investigated. X-ray micro-computed tomographic imaging is used to characterize the distribution and amount of fluids and their interfacial characteristics. Capillary pressure is measured via (1) bulk-phase pressure transducer measurements, and (2) image-based curvature measurements, calculated using a novel 3D curvature algorithm. We distinguish between connected (percolating) and disconnected air clusters: curvatures measured on the connected phase interfaces are used to validate the curvature algorithm and provide an indication of the equilibrium condition of the data; curvature and volume distributions of disconnected clusters provide insight to the snap-off processes occurring during drainage and imbibition under different flow rate conditions.

  19. Hepatic artery perfusion imaging

    International Nuclear Information System (INIS)

    Thrall, J.H.; Gyves, J.W.; Ziessman, H.A.; Ensminger, W.D.

    1985-01-01

    Organ and region-selective intra-arterial chemotherapy have been used for more than two decades to treat malignant neoplasms in the extremities, head and neck region, pelvis, liver, and other areas. Substantial evidence of improved response to regional chemotherapy now exists, but there are stringent requirements for successful application of the regional technique. First, the chemotherapeutic agent employed must have appropriate pharmacokinetic and pharmacodynamic properties. Second, the drug must be reliably delivered to the tumor-bearing area. This typically requires an arteriographic assessment of the vascular supply of the tumor, followed by placement of a therapeutic catheter and confirmation that the ''watershed'' perfusion distribution from the catheter truly encompasses the tumor. Optimal catheter placement also minimizes perfusion of nontarget organs. Radionuclide perfusion imaging with technetium 99m-labeled particles, either microspheres or macroaggregates of albumin, has become the method of choice for making these assessments. Catheter placement itself is considered by many to represent a type of ''therapeutic'' intervention. However, once the catheter is in the hepatic artery the radionuclide perfusion technique can be used to assess adjunctive pharmacologic maneuvers designed to further exploit the regional approach to chemotherapy. This chapter presents the technetium Tc 99m macroaggregated albumin method for assessing catheter placement and the pharmacokinetic rationale for regional chemotherapy, and discusses two promising avenues for further intervention

  20. Extremity perfusion for sarcoma

    NARCIS (Netherlands)

    Hoekstra, Harald Joan

    2008-01-01

    For more than 50 years, the technique of extremity perfusion has been explored in the limb salvage treatment of local, recurrent, and multifocal sarcomas. The "discovery" of tumor necrosis factor-or. in combination with melphalan was a real breakthrough in the treatment of primarily irresectable

  1. Isolated limb perfusion.

    Science.gov (United States)

    Gillespie, Rosalyn; Chantier, Nariane

    1994-12-08

    Growing concern over the rising incidence of malignant melanoma has brought about a need for information on this disorder and the treatment available. Isolated limb perfusion is a relatively new technique used in only a few hospitals. An increased knowledge base will lead to a better understanding of the nursing care required and to a more in-depth care plan.

  2. Myocardial perfusion as an indicator of graft patency after coronary artery bypass surgery

    International Nuclear Information System (INIS)

    Kolibash, A.J.; Call, T.D.; Bush, C.A.; Tetalman, M.R.; Lewis, R.P.

    1980-01-01

    Stress and resting myocardial perfusion were assessed in 38 patients who received 96 grafts. Stress perfusion was evaluated with thallium-201 and resting myocardial blood flow distribution with radiolabeled particles. When both stress and rest perfusion were normal, graft patency was 82% (51 of 62 grafts). Graft patency was also high (81%, 13 of 16) in areas where stress perfusion abnormalities resolved or become less apparent at rest. However, when stress perfusion defects remained unchanged at rest, the graf was likely to be occuluded (73%, 11 of 15). Maintenance of normal rest perfusion or improvement of rest perfusion postoperatively was also associated with a high graft patency rate (80%, 35 of 44), whereas the development of new rest perfusion defects postoperatively implied graft occlusion

  3. Computational Fluid Dynamics Modeling to Improve Natural Flow Rate and Sweet Pepper Productivity in Greenhouse

    OpenAIRE

    W. Limtrakarn; P. Boonmongkol; A. Chompupoung; K. Rungprateepthaworn; J. Kruenate; P. Dechaumphai

    2012-01-01

    Natural flow rate and sweet peppers productivity in tropical greenhouse are improved by CFD simulation is the main objective of this research work. Most of the greenhouse types today are in the arch shape. To develop an improved greenhouse structure for the region, the arch type was built and used as the control model. Mae Sar Mai agriculture research station under the royal project foundation was selected as the field test site. Temperature sensors with data logger were installed to monitor ...

  4. Perfusion CT in childhood stroke—Initial observations and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Zebedin, D., E-mail: doris.zebedin@medunigraz.at [Division of Pediatric Radiology, Department of Radiology, University Hospital LKH Graz (Austria); Sorantin, E.; Riccabona, M. [Division of Pediatric Radiology, Department of Radiology, University Hospital LKH Graz (Austria)

    2013-07-15

    Introduction: To report the preliminary results of contrast-enhanced perfusion multi-detector CT for diagnoses of perfusion disturbances in children with clinical suspicion of stroke. Patients and methods: Within the last two years emergency perfusion CT was performed in ten children (age: 8–17 years, male:female = 3:7) for assessment of suspected childhood stroke. These intracranial perfusion CT, intracranial CT-digital subtraction angiography (CT-DSA) and extracranial CT-angiography (CTA) studies were retrospectively reviewed and compared with MRI, follow-up CT, catheter angiography and final clinical diagnosis. The total dose length product (DLP) for the entire examination was recorded. The image quality of perfusion CT-maps, CT-DSA and CTA were evaluated with a subjective three-point scale ranging from very good to non-diagnostic image quality rating perfusion disturbance, intracranial peripheral vessel depiction, and motion- or streak artifacts. Results: In nine of ten children perfusion CT showed no false positive or false negative results. In one of ten children suffering from migraine focal hypo-perfusion was read as perfusion impairment potentially indicating early stroke, but MRI and MRA follow-up were negative. Overall, perfusion-CT with CT-DSA was rated very good in 80% of cases for the detection of perfusion disturbances and vessel anatomy. Conclusions: In comparison to standard CT, contrast-enhanced perfusion CT improves CTs’ diagnostic capability in the emergency examination of children with a strong suspicion of ischemic cerebral infarction.

  5. Variation in supratentorial cerebrospinal fluid production rate in one day. Measurement by nontriggered phase-contrast magnetic resonance imaging

    International Nuclear Information System (INIS)

    Takahashi, Hiroto; Tanaka, Hisashi; Fujita, Norihiko; Murase, Kenya; Tomiyama, Noriyuki

    2011-01-01

    Measuring the cerebrospinal fluid (CSF) production rate is important for understanding the physiology related to normal conditions and neurological disorders. Triggered phase-contrast magnetic resonance imaging (MRI) has been used to measure CSF production rate, but the use of nontriggered phase-contrast MRI has not been reported. The purposes of this study were to assess the feasibility of using nontriggered phase-contrast MRI to measure CSF flow and to determine whether CSF production exhibits circadian rhythm. The feasibility of phase-contrast MRI was assessed with a phantom simulated human cerebral aqueduct. CSF flow through the cerebral aqueduct was measured with nontriggered phase-contrast MRI four times during 1 day in 10 normal volunteers. In the phantom study, linear regression analysis gave the following measured values (ml/h): 0.80 x (value of steady flow)-10.0 for triggered phase-contrast MRI and 1.27 x (value of steady flow)-12.2 for nontriggered phase-contrast MRI. One-factor analysis of variance showed no significant effect of the time of the measurements (P=0.47). The supratentorial CSF production rate was 510±549 ml/day (mean ± SD). Nontriggered phase-contrast MRI provided good estimates of the flow rate in the phantom study. We observed no circadian rhythm in CSF production. (author)

  6. Computational Fluid Dynamics Modeling to Improve Natural Flow Rate and Sweet Pepper Productivity in Greenhouse

    Directory of Open Access Journals (Sweden)

    W. Limtrakarn

    2012-01-01

    Full Text Available Natural flow rate and sweet peppers productivity in tropical greenhouse are improved by CFD simulation is the main objective of this research work. Most of the greenhouse types today are in the arch shape. To develop an improved greenhouse structure for the region, the arch type was built and used as the control model. Mae Sar Mai agriculture research station under the royal project foundation was selected as the field test site. Temperature sensors with data logger were installed to monitor variation of temperature inside the greenhouse. The measured temperature data were used as the boundary conditions for the CFD analysis. A new greenhouse model with two-step roof shape was designed and the air flow behavior was simulated by using CFD. Regarding CFD results the air flow rate of the new model is about 39% higher than that of old model. The maximum temperature of the new model is lower than that of the old one. The sweet paper growths in both greenhouse models were measured and compared. Results show that the new model obtains 4°C lower maximum temperature in day time, 97% in number and 90% in weight higher the first grade pepper productivity than the old one.

  7. Prognostic value of myocardial perfusion SPECT images in combination with the maximal heart rate at exercise testing in Japanese patients with suspected ischemic heart disease. A sub-analysis of J-ACCESS

    International Nuclear Information System (INIS)

    Ueshima, Kenji; Usami, Satoru; Yasuno, Shinji; Nakao, Kazuwa; Yamashina, Akira; Nishiyama, Osamu; Yamazaki, Takuya; Nishimura, Tsunehiko

    2009-01-01

    We assessed whether a combination of summed stress scores (SSS) using exercise myocardial perfusion single photon emission computed tomography (SPECT) (Ex-SPECT) and maximal heart rate accurately predicts cardiac events through a sub-analysis of J-ACCESS (Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT) which was conducted to evaluate the prognosis of Japanese patients with suspected ischemic heart disease. In J-ACCESS, 2,373 patients with suspected coronary artery disease not receiving beta-blocker treatment underwent Ex-SPECT. These patients were categorized into the following four groups: Group A [achieved target heart rate (THR) and SSS<4: n=631], B (did not achieve THR and SSS<4: n=612), C (achieved THR and SSS≥4: n=570), and D (did not achieve THR and SSS≥4: n=560). We evaluated the incidence rate of cardiac events including cardiac death, myocardial infarction, and heart failure requiring hospital admission during a 3-year period. In Group A, B, C, and D, 9 of 631 (1.4%), 15 of 612 (2.4%), 23 of 570 (4.0%) and 30 of 560 (5.4%) patients experienced cardiac events, respectively. Although the hazard ratio of the SSS≥4 was 2.45 (p<0.001) and that of the attained THR was 0.69 (p=0.10) in the multiple Cox regression analysis, Kaplan-Meier curves showed that the cardiac events rate was lower in the order of A, B, C, and D (p<0.001). The combination of SSS using Ex-SPECT and the maximal heart rate is a useful predictor of cardiac events in patients with suspected coronary artery disease. (author)

  8. Spatio-temporal analysis of blood perfusion by imaging photoplethysmography

    Science.gov (United States)

    Zaunseder, Sebastian; Trumpp, Alexander; Ernst, Hannes; Förster, Michael; Malberg, Hagen

    2018-02-01

    Imaging photoplethysmography (iPPG) has attracted much attention over the last years. The vast majority of works focuses on methods to reliably extract the heart rate from videos. Only a few works addressed iPPGs ability to exploit spatio-temporal perfusion pattern to derive further diagnostic statements. This work directs at the spatio-temporal analysis of blood perfusion from videos. We present a novel algorithm that bases on the two-dimensional representation of the blood pulsation (perfusion map). The basic idea behind the proposed algorithm consists of a pairwise estimation of time delays between photoplethysmographic signals of spatially separated regions. The probabilistic approach yields a parameter denoted as perfusion speed. We compare the perfusion speed versus two parameters, which assess the strength of blood pulsation (perfusion strength and signal to noise ratio). Preliminary results using video data with different physiological stimuli (cold pressure test, cold face test) show that all measures are influenced by those stimuli (some of them with statistical certainty). The perfusion speed turned out to be more sensitive than the other measures in some cases. However, our results also show that the intraindividual stability and interindividual comparability of all used measures remain critical points. This work proves the general feasibility of employing the perfusion speed as novel iPPG quantity. Future studies will address open points like the handling of ballistocardiographic effects and will try to deepen the understanding of the predominant physiological mechanisms and their relation to the algorithmic performance.

  9. The Use of an Acellular Oxygen Carrier in a Human Liver Model of Normothermic Machine Perfusion.

    Science.gov (United States)

    Laing, Richard W; Bhogal, Ricky H; Wallace, Lorraine; Boteon, Yuri; Neil, Desley A H; Smith, Amanda; Stephenson, Barney T F; Schlegel, Andrea; Hübscher, Stefan G; Mirza, Darius F; Afford, Simon C; Mergental, Hynek

    2017-11-01

    Normothermic machine perfusion of the liver (NMP-L) is a novel technique that preserves liver grafts under near-physiological conditions while maintaining their normal metabolic activity. This process requires an adequate oxygen supply, typically delivered by packed red blood cells (RBC). We present the first experience using an acellular hemoglobin-based oxygen carrier (HBOC) Hemopure in a human model of NMP-L. Five discarded high-risk human livers were perfused with HBOC-based perfusion fluid and matched to 5 RBC-perfused livers. Perfusion parameters, oxygen extraction, metabolic activity, and histological features were compared during 6 hours of NMP-L. The cytotoxicity of Hemopure was also tested on human hepatic primary cell line cultures using an in vitro model of ischemia reperfusion injury. The vascular flow parameters and the perfusate lactate clearance were similar in both groups. The HBOC-perfused livers extracted more oxygen than those perfused with RBCs (O2 extraction ratio 13.75 vs 9.43 % ×10 per gram of tissue, P = 0.001). In vitro exposure to Hemopure did not alter intracellular levels of reactive oxygen species, and there was no increase in apoptosis or necrosis observed in any of the tested cell lines. Histological findings were comparable between groups. There was no evidence of histological damage caused by Hemopure. Hemopure can be used as an alternative oxygen carrier to packed red cells in NMP-L perfusion fluid.

  10. Effect of bore fluid flow rate on formation and properties of hollow fibers

    Science.gov (United States)

    Alobaidy, Asrar A.; Sherhan, Bashir Y.; Barood, Areej D.; Alsalhy, Qusay F.

    2017-12-01

    In this work, for high performance and wide range of ultrafiltration applications, the effects of the most widely used values of internal coagulant flow rates (ICFR) (i.e., 2.6, 3.6, 4, 5, 7, 9, 11, and 13 ml/min) on the different features of the polyvinylchloride hollow fiber have been investigated. Both the idealized straight and the cylindrical pore with small effect of tortuosity were approximately obtained through the effect of ICFR. Atomic force microscope (AFM), scanning electron microscope (SEM), and ultrafiltration measurements were utilized to characterize the hollow fibers. The SEM and AFM results indicated that the cross-sectional morphology of the fibers is changed significantly with various ICFR. The structure of the inner surface was also changed from an open cellular structure to a porous structure by means of high pore density and small pore diameter. In addition, the membrane thickness was reduced by 314% with an increase in the ICFR from 2.6 to 13 ml/min. The pure water permeation flux was improved 17 times when ICFR was increased to 13 ml/min, while the BSA rejection remained within the acceptable range (from 93.4 to 90.4) when the ICFR was increased from 2.6 to 9 ml/min.

  11. 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.)

  12. Nuclear magnetic resonance studies of intracellular ions in perfused from heart

    International Nuclear Information System (INIS)

    Burnstein, D.; Fossel, E.T.

    1987-01-01

    Intracellular sodium, potassium, and lithium were observed in a perfused frog heart by nuclear magnetic resonance (NMR) spectroscopy. A perfusate buffer containing the shift reagent, dysprosium tripolyphosphate, was used in combination with mathematical filtering or presaturation of the extracellular resonance to separate the intra- and extracellular sodium NMR signals. Addition of 10 μM ouabain to the perfusate, perfusion with a zero potassium, low-calcium buffer, and replacement of 66% of the perfusate sodium with lithium resulted in changes in the intracellular sodium levels. An increase of 45% in the intracellular sodium was observed when changing the pacing rate from 0 to 60 beats/min (with proportional changes for intermediate pacing rates). The ratio of intracellular potassium to sodium concentration was determined to be 2.3 by NMR, indicating that a substantial amount of the intracellular potassium is undetectable with these NMR method. In addition, intracellular lithium was observed during perfusion with a lithium-containing perfusate

  13. Sill intrusion driven fluid flow and vent formation in volcanic basins: Modeling rates of volatile release and paleoclimate effects

    Science.gov (United States)

    Iyer, Karthik; Schmid, Daniel

    2016-04-01

    Evidence of mass extinction events in conjunction with climate change occur throughout the geological record and may be accompanied by pronounced negative carbon isotope excursions. The processes that trigger such globally destructive changes are still under considerable debate. These include mechanisms such as poisoning from trace metals released during large volcanic eruptions (Vogt, 1972), CO2 released from lava degassing during the formation of Large Igneous Provinces (LIPs) (Courtillot and Renne, 2003) and CH4 release during the destabilization of sub-seafloor methane (Dickens et al., 1995), to name a few. Thermogenic methane derived from contact metamorphism associated with magma emplacement and cooling in sedimentary basins has been recently gaining considerable attention as a potential mechanism that may have triggered global climate events in the past (e.g. Svensen and Jamtveit, 2010). The discovery of hydrothermal vent complexes that are spatially associated with such basins also supports the discharge of greenhouse gases into the atmosphere (e.g. Jamtveit et al., 2004; Planke et al., 2005; Svensen et al., 2006). A previous study that investigated this process using a fluid flow model (Iyer et al., 2013) suggested that although hydrothermal plume formation resulting from sill emplacement may indeed release large quantities of methane at the surface, the rate at which this methane is released into the atmosphere is too slow to trigger, by itself, some of the negative δ13C excursions observed in the fossil record over short time scales observed in the fossil record. Here, we reinvestigate the rates of gas release during sill emplacement in a case study from the Harstad Basin off-shore Norway with a special emphasis on vent formation. The presented study is based on a seismic line that crosses multiple sill structures emplaced around 55 Ma within the Lower Cretaceous sediments. A single well-defined vent complex is interpreted above the termination of the

  14. Vascular Endothelial Growth Factor Concentration in Chronic Subdural Hematoma Fluid Is Related to Computed Tomography Appearance and Exudation Rate

    Science.gov (United States)

    Weigel, Ralf; Hohenstein, Axel

    2014-01-01

    Abstract Chronic subdural hematoma (CSH) is characterized by a net increase of volume over time. Major underlying mechanisms appear to be hemorrhagic episodes and a continuous exudation, which may be studied using labeled proteins to yield an exudation rate in a given patient. We tested the hypothesis that the concentration of vascular endothelial growth factor (VEGF) in hematoma fluid correlates with the rate of exudation. Concentration of VEGF was determined in 51 consecutive patients with CSH by the sandwich immune enzyme-linked immunosorbent assay technique. Mean values were correlated with exudation rates taken from the literature according to the appearance of CSH on computed tomography (CT) images. The CT appearance of each CSH was classified as hypodense, isodense, hyperdense, or mixed density. Mean VEGF concentration was highest in mixed-density hematomas (22,403±4173 pg/mL; mean±standard error of the mean; n=27), followed by isodense (9715±1287 pg/mL; n=9) and hypodense (5955±610 pg/mL; n=18) hematomas. Only 1 patient with hyperdense hematoma fulfilled the inclusion criteria, and the concentration of VEGF found in this patient was 24,200 pg/mL. There was a statistically significant correlation between VEGF concentrations and exudation rates in the four classes of CT appearance (r=0.98). The current report is the first to suggest a pathophysiological link between the VEGF concentration and the exudation rate underlying the steady increase of hematoma volume and CT appearance.With this finding, the current report adds another piece of evidence in favor of the pathophysiological role of VEGF in the development of CSH, including mechanisms contributing to hematoma growth and CT appearance. PMID:24245657

  15. Gray matter perfusion correlates with disease severity in ALS.

    Science.gov (United States)

    Rule, Randall R; Schuff, Norbert; Miller, Robert G; Weiner, Michael W

    2010-03-09

    The goal of this study is to determine if regional brain perfusion, as measured by arterial spin labeling (ASL) MRI, is correlated with clinical measures of amyotrophic lateral sclerosis (ALS) disease severity. The presence of such a relationship would indicate a possible role for ASL perfusion as a marker of disease severity and upper motor neuron involvement in ALS. Disease severity was assessed in 16 subjects with ALS (age 54 +/- 11) using the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) and the pulmonary function measure, forced vital capacity (FVC). Upper motor neuron involvement was assessed by testing rapid tapping of the fingers and feet. Magnetic resonance perfusion images were coregistered with structural T1-weighted MRI, corrected for partial volume effects using the structural images and normalized to a study-specific atlas. Correlations between perfusion and ALS disease severity were analyzed, using statistical parametric mapping, and including age as a factor. Analyses were adjusted for multiple clusters. ALS severity, as measured by the ALSFRS and FVC, was correlated with gray matter perfusion. This correlation was predominantly observed in the hemisphere contralateral to the more affected limbs. ALSFRS scores correlated with perfusion in the contralateral frontal and parietal lobe (p frontal lobe (p frontal lobe (p Upper motor neuron involvement, as measured by rapid finger tapping, correlated bilaterally with perfusion in the middle cingulate gyrus (p < 0.001). Amyotrophic lateral sclerosis (ALS) severity is correlated with brain perfusion as measured by arterial spin labeling (ASL) perfusion. This correlation appears to be independent of brain atrophy. ASL perfusion may be a useful tool for monitoring disease progression and assessing treatment effects in ALS.

  16. [Significance of amnioinfusion and amniotic fluid exchange under continuous internal fetal heart rate monitoring for management of fetal distress during labor].

    Science.gov (United States)

    Zhao, S; Ai, L; Zhang, H

    2000-01-01

    To discuss the significance of amnioinfusion and amniotic fluid exchange under continuous internal fetal heart rate (FHR) monitoring for management of fetal distress during labor. 136 cases with frequent variable deceleration (VD) and meconium stained amniotic fluid during labor were divided into two groups: the study group (68 cases) and the control group (68 cases). The former were treated by amnioinfusion and amniotic fluid exchange, while oxygen inhalation, change of body position, and intravenous infusion for the control group. In the study group, VD disappeared or relieved in 62 cases obviously, and the efficacy rate reached 91.2% (62/68). 48 cases with II degree meconium stained amniotic fluid were treated by amniotic fluid exchange, amniotic fluid became clear or turned to I degree stained in 39 cases. In the control group, VD relieved in 20 cases, the efficacy rate was 19.4%, significantly lower than that of the study group (P 0.05). Amnioinfusion and AF exchange during labor are one of the effective treatment methods for fetal distress and prevention for MAS.

  17. Perfusion based cell culture chips

    DEFF Research Database (Denmark)

    Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

    2010-01-01

    Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures...... and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers....

  18. Dynamic perfusion CT: Optimizing the temporal resolution for the calculation of perfusion CT parameters in stroke patients

    Energy Technology Data Exchange (ETDEWEB)

    Kaemena, Andreas [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany)], E-mail: andreas.kaemena@charite.de; Streitparth, Florian; Grieser, Christian; Lehmkuhl, Lukas [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany); Jamil, Basil [Department of Radiotherapy, Charite-Medical University Berlin, Schumannstr. 20/21, D-10117 Berlin (Germany); Wojtal, Katarzyna; Ricke, Jens; Pech, Maciej [Department of Radiology, Charite-Medical University Berlin, Augustenburger Platz 1, D-13353 Berlin (Germany)

    2007-10-15

    Purpose: To assess the influence of different temporal sampling rates on the accuracy of the results from cerebral perfusion CTs in patients with an acute ischemic stroke. Material and methods: Thirty consecutive patients with acute stroke symptoms received a dynamic perfusion CT (LightSpeed 16, GE). Forty millilitres of iomeprol (Imeron 400) were administered at an injection rate of 4 ml/s. After a scan delay of 7 s, two adjacent 10 mm slices at 80 kV and 190 mA were acquired in a cine mode technique with a cine duration of 49 s. Parametric maps for the blood flow (BF), blood volume (BV) and mean transit time (MTT) were calculated for temporal sampling intervals of 0.5, 1, 2, 3 and 4 s using GE's Perfusion 3 software package. In addition to the quantitative ROI data analysis, a visual perfusion map analysis was performed. Results: The perfusion analysis proved to be technically feasible with all patients. The calculated perfusion values revealed significant differences with regard to the BF, BV and MTT, depending on the employed temporal resolution. The perfusion contrast between ischemic lesions and healthy brain tissue decreased continuously at the lower temporal resolutions. The visual analysis revealed that ischemic lesions were best depicted with sampling intervals of 0.5 and 1 s. Conclusion: We recommend a temporal scan resolution of two images per second for the best detection and depiction of ischemic areas.

  19. Fluid Replacement in Treatment of Hypovolemia and Shock: Crystalloids and Colloids

    Directory of Open Access Journals (Sweden)

    Fatih Yildiz

    2013-06-01

    Full Text Available Shock is a pathologic state with high mortality rate and characterized by a reduction of systemic tissue perfusion and decresead oxygen delivery. Absolute or relative hypovolemia is a common pathology of most shock types. Correction of hypovolemia might reverse the disturbance and increase the tissue perfusion. Fluid resuscitation with crystalloid and colloid solutions can carry the risk of increasing morbidity and mortality if not used properly. Although crystalloid and colloid solutions are considered to have equal efficacy and safety profile, recent studies showed that this assumption may not be correct. Early and effective management of hypovolemia is the cornerstone of shock resuscitation. Initial management of patients with septic shock and hypovolemia should be done with 30ml/kg of crystalloids. Proper fluid replacement and resuscitation algoritms might increase the survival rate. [Archives Medical Review Journal 2013; 22(3.000: 347-361

  20. Application of Fermat's Principle to Calculation of the Errors of Acoustic Flow-Rate Measurements for a Three-Dimensional Fluid Flow or Gas

    Science.gov (United States)

    Petrov, A. G.; Shkundin, S. Z.

    2018-01-01

    Fermat's variational principle is used for derivation of the formula for the time of propagation of a sonic signal between two set points A and B in a steady three-dimensional flow of a fluid or gas. It is shown that the fluid flow changes the time of signal reception by a value proportional to the flow rate independently of the velocity profile. The time difference in the reception of the signals from point B to point A and vice versa is proportional with a high accuracy to the flow rate. It is shown that the relative error of the formula does not exceed the square of the largest Mach number. This makes it possible to measure the flow rate of a fluid or gas with an arbitrary steady subsonic velocity field.

  1. Measurement of temporal regional cerebral perfusion with single-photon emission tomography predicts rate of decline in language function and survival in early Alzheimer`s disease

    Energy Technology Data Exchange (ETDEWEB)

    Claus, J.J.; Walstra, G.J.M.; Hijdra, A.; Gool, W.A. van [Department of Neurology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Royen, E.A. van [Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam (Netherlands); Verbeeten, B. Jr. [Department of Radiology, Academic Medical Center, University of Amsterdam (Netherlands)

    1999-03-01

    We determined the relationship between regional cerebral blood flow (rCBF) measured with single-photon emission tomography (SPET) and decline in cognitive function and survival in Alzheimer`s disease. In a prospective follow-up study, 69 consecutively referred patients with early probable Alzheimer`s disease (NINCDS/ADRDA criteria) underwent SPET performed at the time of initial diagnosis using technetium-99m-labelled hexamethylpropylene amine oxime. Neuropsychological function was assessed at baseline and after 6 months and survival data were available on all patients, extending to 5.5 years of follow-up. Lower left temporal (P<0.01) and lower left parietal (P<0.01) rCBF were statistically significantly related to decline in language function after 6 months. The association between left temporal rCBF and survival was also statistically significant (P<0.05) using Cox proportional hazards regression analysis. Performing analysis with quartiles of the distribution, we found a threshold effect for low left temporal rCBF (rCBF<73.7%, P<0.01) and high risk of mortality. In this lowest quartile, median survival time was 2.7 years (follow-up to 5.2 years), compared with 4.4 years in the other quartiles (follow-up to 5.5 years). Kaplan-Meier survival curves showed statistically significant (P<0.05, log rank test) survival curves for the lowest versus other quartiles of left temporal rCBF. All results were unaffected by adjustment for age, sex, dementia severity, duration of symptoms, education and ratings of local cortical atrophy. We conclude that left temporal rCBF predicts decline in language function and survival in patients with early probable Alzheimer`s disease, with a threshold effect of low rCBF and high risk of mortality. (orig.) With 3 figs., 3 tabs., 44 refs.

  2. Measurement of temporal regional cerebral perfusion with single-photon emission tomography predicts rate of decline in language function and survival in early Alzheimer's disease

    International Nuclear Information System (INIS)

    Claus, J.J.; Walstra, G.J.M.; Hijdra, A.; Gool, W.A. van; Royen, E.A. van; Verbeeten, B. Jr.

    1999-01-01

    We determined the relationship between regional cerebral blood flow (rCBF) measured with single-photon emission tomography (SPET) and decline in cognitive function and survival in Alzheimer's disease. In a prospective follow-up study, 69 consecutively referred patients with early probable Alzheimer's disease (NINCDS/ADRDA criteria) underwent SPET performed at the time of initial diagnosis using technetium-99m-labelled hexamethylpropylene amine oxime. Neuropsychological function was assessed at baseline and after 6 months and survival data were available on all patients, extending to 5.5 years of follow-up. Lower left temporal (P<0.01) and lower left parietal (P<0.01) rCBF were statistically significantly related to decline in language function after 6 months. The association between left temporal rCBF and survival was also statistically significant (P<0.05) using Cox proportional hazards regression analysis. Performing analysis with quartiles of the distribution, we found a threshold effect for low left temporal rCBF (rCBF<73.7%, P<0.01) and high risk of mortality. In this lowest quartile, median survival time was 2.7 years (follow-up to 5.2 years), compared with 4.4 years in the other quartiles (follow-up to 5.5 years). Kaplan-Meier survival curves showed statistically significant (P<0.05, log rank test) survival curves for the lowest versus other quartiles of left temporal rCBF. All results were unaffected by adjustment for age, sex, dementia severity, duration of symptoms, education and ratings of local cortical atrophy. We conclude that left temporal rCBF predicts decline in language function and survival in patients with early probable Alzheimer's disease, with a threshold effect of low rCBF and high risk of mortality. (orig.)

  3. Gammagraphy of cerebral perfusion

    International Nuclear Information System (INIS)

    Vazquez, Silvia

    2003-01-01

    Important aspects of the gammagraphy of cerebral perfusion and the diverse clinical applications in the neurological diseases are comment in this article. We focus in the usefulness of the photon emission cerebral tomography (SPECT) and its capacity to cross the hemato encephalic barrier through the use of radiopharmacons like 99 mTc-H M-PAO and 99mTc-EDC, thus managing to offer functional data on the captantes neurons of the radiopharmacon. The clinical applications of SPECT are studied; cerebrovascular disease, transient ischemic attacks, dementias, Alzheimer disease, as well as other neurological diseases are referred. (The author)

  4. Does flushing the endometrial cavity with follicular fluid after oocyte retrieval affect pregnancy rates in subfertile women undergoing intracytoplasmic sperm injection? A randomized controlled trial.

    Science.gov (United States)

    Hashish, N M; Badway, H S; Abdelmoty, H I; Mowafy, A; Youssef, M A F M

    2014-05-01

    Follicular fluid of mature oocytes is rich in growth factors and cytokines that may exert paracrine and autocrine effects on implantation. The aim of this study was to investigate if flushing the endometrial cavity with follicular fluid after oocyte retrieval improved pregnancy rates in subfertile women undergoing intracytoplasmic sperm injection (ICSI). One hundred subfertile women undergoing ICSI between April 2012 and September 2012 at the centre for reproductive medicine, Cairo University, Egypt were enrolled in this open label, parallel randomized controlled study. Patients were randomized into two groups at the start of treatment using a computer-generated programme and sealed opaque envelopes: the follicular fluid group (n=50) and the control group (n=50). Inclusion criteria were: age 20-38 years; basal follicle-stimulating hormone 1000pg/ml and failure in previous in-vitro fertilization/ICSI cycles; and severe male factor infertility. Clinical pregnancy and implantation rates were higher in the follicular fluid group compared with the control group [354% (17/48) vs 319% (15/47); p=0718] and (18.6% vs 11.3%; p=0.153), respectively. However, the difference was not statistically significant. Flushing the endometrial cavity with follicular fluid after oocyte retrieval neither improved nor adversely affected clinical pregnancy and implantation rates in subfertile women undergoing ICSI. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. The clearance concept with special reference to determination of glomerular filtration rate in patients with fluid retention

    DEFF Research Database (Denmark)

    Henriksen, Ulrik L; Henriksen, Jens H

    2014-01-01

    In subjects without fluid retention, the total plasma clearance of a renal filtration indicator (inulin, (99m) Tc-DTPA, (51) Cr-EDTA) is close to the urinary plasma clearance. Conversely, in patients with fluid retention (oedema, pleural effusions, ascites), there is a substantial discrepancy...

  6. Job analysis and student assessment tool: perfusion education clinical preceptor.

    Science.gov (United States)

    Riley, Jeffrey B

    2007-09-01

    The perfusion education system centers on the cardiac surgery operating room and the perfusionist teacher who serves as a preceptor for the perfusion student. One method to improve the quality of perfusion education is to create a valid method for perfusion students to give feedback to clinical teachers. The preceptor job analysis consisted of a literature review and interviews with preceptors to list their critical tasks, critical incidents, and cognitive and behavioral competencies. Behaviorally anchored rating traits associated with the preceptors' tasks were identified. Students voted to validate the instrument items. The perfusion instructor rating instrument with a 0-4, "very weak" to "very strong" Likert rating scale was used. The five preceptor traits for student evaluation of clinical instruction (SECI) are as follows: The clinical instructor (1) encourages self-learning, (2) encourages clinical reasoning, (3) meets student's learning needs, (4) gives continuous feedback, and (5) represents a good role model. Scores from 430 student-preceptor relationships for 28 students rotating at 24 affiliate institutions with 134 clinical instructors were evaluated. The mean overall good preceptor average (GPA) was 3.45 +/- 0.76 and was skewed to the left, ranging from 0.0 to 4.0 (median = 3.8). Only 21 of the SECI relationships earned a GPA SECI are methods to provide valid information to improve the quality of a perfusion education program.

  7. Development of an Extracorporeal Perfusion Device for Small Animal Free Flaps.

    Directory of Open Access Journals (Sweden)

    Andreas M Fichter

    Full Text Available Extracorporeal perfusion (ECP might prolong the vital storage capabilities of composite free flaps, potentially opening a wide range of clinical applications. Aim of the study was the development a validated low-cost extracorporeal perfusion model for further research in small animal free flaps.After establishing optimal perfusion settings, a specially designed extracorporeal perfusion system was evaluated during 8-hour perfusion of rat epigastric flaps followed by microvascular free flap transfer. Controls comprised sham-operation, ischemia and in vivo perfusion. Flaps and perfusate (diluted blood were closely monitored by blood gas analysis, combined laser Doppler flowmetry and remission spectroscopy and Indocyanine-Green angiography. Evaluations were complemented by assessment of necrotic area and light microscopy at day 7.ECP was established and maintained for 8 hours with constant potassium and pH levels. Subsequent flap transfer was successful. Notably, the rate of necrosis of extracorporeally perfused flaps (27% was even lower than after in vivo perfusion (49%, although not statistically significant (P = 0,083. After sham-operation, only 6% of the total flap area became necrotic, while 8-hour ischemia led to total flap loss (98%. Angiographic and histological findings confirmed these observations.Vital storage capabilities of microvascular flaps can be prolonged by temporary ECP. Our study provides important insights on the pathophysiological processes during extracorporeal tissue perfusion and provides a validated small animal perfusion model for further studies.

  8. Characterization of micro-invasive trabecular bypass stents by ex vivo perfusion and computational flow modeling

    Directory of Open Access Journals (Sweden)

    Hunter KS

    2014-03-01

    Full Text Available Kendall S Hunter,1 Todd Fjield,2 Hal Heitzmann,2 Robin Shandas,1 Malik Y Kahook3 1Department of Bioengineering, University of Colorado Denver, Aurora, CO, USA; 2Glaukos Corporation, Laguna Hills, CA, USA; 3University of Colorado Hospital Eye Center, Aurora, CO, USA Abstract: Micro-invasive glaucoma surgery with the Glaukos iStent® or iStent inject® (Glaukos Corporation, Laguna Hills, CA, USA is intended to create a bypass through the trabecular meshwork to Schlemm's canal to improve aqueous outflow through the natural physiologic pathway. While the iStent devices have been evaluated in ex vivo anterior segment models, they have not previously been evaluated in whole eye perfusion models nor characterized by computational fluid dynamics. Intraocular pressure (IOP reduction with the iStent was evaluated in an ex vivo whole human eye perfusion model. Numerical modeling, including computational fluid dynamics, was used to evaluate the flow through the stents over physiologically relevant boundary conditions. In the ex vivo model, a single iStent reduced IOP by 6.0 mmHg from baseline, and addition of a second iStent further lowered IOP by 2.9 mmHg, for a total IOP reduction of 8.9 mmHg. Computational modeling showed that simulated flow through the iStent or iStent inject is smooth and laminar at physiological flow rates. Each stent was computed to have a negligible flow resistance consistent with an expected significant decrease in IOP. The present perfusion results agree with prior clinical and laboratory studies to show that both iStent and iStent inject therapies are potentially titratable, providing clinicians with the opportunity to achieve lower target IOPs by implanting additional stents. Keywords: glaucoma, iStent, trabecular bypass, intraocular pressure, ab-interno, CFD

  9. PET imaging of cerebral perfusion and oxygen metabolism in stroke

    Energy Technology Data Exchange (ETDEWEB)

    Pointon, O.; Yasaka, M.; Berlangieri, S.U.; Newton, M.R.; Thomas, D.L.; Chan, C.G.; Egan, G.F.; Tochon-Danguy, H.J.; O``Keefe, G.; Donnan, G.A.; McKay, W.J. [Austin Hospital, Melbourne, VIC (Australia). Centre for PET and Depts of Nuclear Medicine and Neurology

    1998-03-01

    Full text: Stroke remains a devastating clinical event with few therapeutic options. In patients with acute stroke, we studied the cerebral perfusion and metabolic patterns with {sup 15}O-CO{sub 2} or H{sub 2}O and {sup 15}O-O{sub 2} positron emission tomography and correlated these findings to the clinical background. Forty three patients underwent 45 studies 0-23 days post-stroke (mean 7 days). Fifteen patients showed luxury perfusion (Group A), 10 had matched low perfusion and metabolism (B) and 3 showed mixed pattern including an area of misery perfusion (C). Seventeen showed no relevant abnormality (D) and there were no examples of isolated misery perfusion. Twelve of the 15 in Group A had either haemorrhagic transformation on CT, re-opening on angiography, or a cardioembolic mechanism. In contrast only 5/10 in Group B, 0/3 in Group C and 2/17 in Group D had these features. Although 7/10 in group B had moderate or large size infarcts on CT the incidence of haemorrhagic transformation was low (2/10) and significant carotid stenoses were more common in those studied (5/8) compared with the other groups. Misery perfusion was not seen beyond five days. Thus, luxury perfusion seems to be related to a cardio-embolic mechanism or reperfusion. Matched low perfusion and metabolism was associated with a low rate of haemorrhagic transformation despite a high incidence of moderate to large size infarcts. Misery perfusion is an early phenomenon in the evolution of ischaemic stroke.

  10. Intestinal perfusion in the study of intestinal absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Several techniques for studying absorption by means of intestinal perfusion have been developed. While the principle is simple, the practice is complicated by absorption of the solvent and by excretion of fluid into the lumen. To improve reliability a ''marker'' is incorporated into the system; it should behave as nearly as possible like the nutrient of interest, except that it should be unabsorbable. A great many markers, including several labelled with radionuclides, have been developed for use with numerous nutrients, and perfusion methods using double or triple tubes or occlusive balloons have been tested. The perfusion technique is too complicated for routine diagnostic use, but it offers at present the only possibility of studying the function of defined sections of the small intestine in the intact human. (author)

  11. Beyond Poiseuille: Preservation Fluid Flow in an Experimental Model

    Directory of Open Access Journals (Sweden)

    Saurabh Singh

    2013-01-01

    Full Text Available Poiseuille’s equation describes the relationship between fluid viscosity, pressure, tubing diameter, and flow, yet it is not known if cold organ perfusion systems follow this equation. We investigated these relationships in an ex vivo model and aimed to offer some rationale for equipment selection. Increasing the cannula size from 14 to 20 Fr increased flow rate by a mean (SD of 13 (12%. Marshall’s hyperosmolar citrate was three times less viscous than UW solution, but flows were only 45% faster. Doubling the bag pressure led to a mean (SD flow rate increase of only 19 (13%, not twice the rate. When external pressure devices were used, 100 mmHg of continuous pressure increased flow by a mean (SD of 43 (17% when compared to the same pressure applied initially only. Poiseuille’s equation was not followed; this is most likely due to “slipping” of preservation fluid within the plastic tubing. Cannula size made little difference over the ranges examined; flows are primarily determined by bag pressure and fluid viscosity. External infusor devices require continuous pressurisation to deliver high flow. Future studies examining the impact of perfusion variables on graft outcomes should include detailed equipment descriptions.

  12. In-vivo quantitative evaluation of perfusion zones and perfusion gradient in the deep inferior epigastric artery perforator flap

    Science.gov (United States)

    Saint-Cyr, Michel; Lakhiani, Chrisovalantis; Cheng, Angela; Mangum, Michael; Liang, Jinyang; Teotia, Sumeet; Livingston, Edward H.; Zuzak, Karel J.

    2013-03-01

    The selection of well-vascularized tissue during DIEP flap harvest remains controversial. While several studies have elucidated cross-midline perfusion, further characterization of perfusion to the ipsilateral hemiabdomen is necessary for minimizing rates of fat necrosis or partial fat necrosis in bilateral DIEP flaps. Eighteen patients (29 flaps) underwent DIEP flap harvest using a prospectively designed protocol. Perforators were marked and imaged with a novel system for quantitatively measuring tissue oxygenation, the Digital Light Hyperspectral Imager. Images were then analyzed to determine if perforator selection influenced ipsilateral flap perfusion. Flaps based on a single lateral row perforator (SLRP) were found to have a higher level of hemoglobin oxygenation in Zone I (mean %HbO2 = 76.1) compared to single medial row perforator (SMRP) flaps (%HbO2 = 71.6). Perfusion of Zone III relative to Zone I was similar between SLRP and SMRP flaps (97.4% vs. 97.9%, respectively). These differences were not statistically significant (p>0.05). Perfusion to the lateral edge of the flap was slightly greater for SLRP flaps compared SMRP flaps (92.1% vs. 89.5%, respectively). SMRP flaps had superior perfusion travelling inferiorly compared to SLRP flaps (88.8% vs. 83.9%, respectively). Overall, it was observed that flaps were better perfused in the lateral direction than inferiorly. Significant differences in perfusion gradients directed inferiorly or laterally were observed, and perforator selection influenced perfusion in the most distal or inferior aspects of the flap. This suggests broader clinical implications for flap design that merit further investigation.

  13. Focused Fluid Flow along Convergent Plate Boundaries - Deriving Flow Rates along Faults from Local Upwarping of the Base of the Gas Hydrate Stability Zone

    Science.gov (United States)

    Kunath, P.; Chi, W. C.; Liu, C. S.

    2017-12-01

    Convergent plate boundaries provide the ideal opportunity to examine the interactions of deformation, fluid flow and gas hydrate stability. However, there are still processes and parameters that remain unclear or scarce. This may be in part due to the fact that in situ determination of fluid flow rate is very difficult. Here, we present a newly developed 2-D hydrothermal model for (1) simulating the steady state, thermal effect of forced heat advection along a thin and shallow dipping fault and (2) quantifying fluid velocities required to deliver a thermal anomalies manifested at the bottom-simulating reflector (BSR) at its intersection with the fault zone. Assuming the horizontal thermal conduction is negligible, we derive our model using only a few crucial parameters: (a) the thermal conductivity structure between seafloor and fault; (b) the temperature at BSR depth and the seafloor; (c) fluid flow rate; (d) geometry of the fault conduit, including depth and thickness. Temperature disturbance is then described as a function of Peclet number and of the dip of the fault. Application of our model to Site 892 at Cascadia accretionary wedge (ODP Leg 146), where borehole data provide excellent thermal constraints on the hydrology, shows consistent results. By comparing the temperatures derived at the BSRs with the temperature field of our model, the results demonstrate that the temperature discrepancy is about 0 - 0.5 oC. We propose that this simple approach can provide, on the basis of a few parameters, rough estimate of the disturbance of the temperature caused by advecting fluid. Localized lateral BSR-based heat flow variations have been observed near thrust faults along many convergent plate boundaries around the world and are associated with strong localized fluid flow. We wish to further testing this approach using other seismic datasets to estimate first order of magnitude fluid migration patterns in other convergent boundaries.

  14. Dual-energy perfusion-CT of pancreatic adenocarcinoma

    International Nuclear Information System (INIS)

    Klauß, M.; Stiller, W.; Pahn, G.; Fritz, F.; Kieser, M.; Werner, J.; Kauczor, H.U.; Grenacher, L.

    2013-01-01

    Purpose: To evaluate the feasibility of dual-energy CT (DECT)-perfusion of pancreatic carcinomas for assessing the differences in perfusion, permeability and blood volume of healthy pancreatic tissue and histopathologically confirmed solid pancreatic carcinoma. Materials and methods: 24 patients with histologically proven pancreatic carcinoma were examined prospectively with a 64-slice dual source CT using a dynamic sequence of 34 dual-energy (DE) acquisitions every 1.5 s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). 80 kV p , 140 kV p , and weighted average (linearly blended M0.3) 120 kV p -equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool (Body-PCT, Siemens Medical Solutions, Erlangen, Germany) for estimating perfusion, permeability, and blood volume values. Color-coded parameter maps were generated. Results: In all 24 patients dual-energy CT-perfusion was. All carcinomas could be identified in the color-coded perfusion maps. Calculated perfusion, permeability and blood volume values were significantly lower in pancreatic carcinomas compared to healthy pancreatic tissue. Weighted average 120 kV p -equivalent perfusion-, permeability- and blood volume-values determined from DE image data were 0.27 ± 0.04 min −1 vs. 0.91 ± 0.04 min −1 (p −1 vs. 0.67 ± 0.05 *0.5 min −1 (p = 0.06) and 0.49 ± 0.07 min −1 vs. 1.28 ± 0.11 min −1 (p p the standard deviations of the kV p 120 kV p -equivalent values were manifestly smaller. Conclusion: Dual-energy CT-perfusion of the pancreas is feasible. The use of DECT improves the accuracy of CT-perfusion of the pancreas by fully exploiting the advantages of enhanced iodine contrast at 80 kV p in combination with the noise reduction at 140 kV p . Therefore using dual-energy perfusion data could improve the delineation of pancreatic carcinomas

  15. Enhanced magnetic resonance pulmonary perfusion imaging in diagnosing pulmonary embolism: preliminary investigation

    International Nuclear Information System (INIS)

    Huang Xiaoyong; Du Jing; Zhang Zhaoqi; Guo Xi; Yan Zixu; Jiang Hong; Wang Wei

    2005-01-01

    Objective: This study was designed to investigate the sensitivity and specificity of magnetic resonance pulmonary perfusion imaging (MRPP) in diagnosing pulmonary embolism (PE) compared with enhanced magnetic resonance pulmonary angiography (MRPA) and pulmonary radionuclide perfusion imaging. Methods: Fourteen patients were definitely diagnosed as PE, whose ages were from 19 to 71 years old and mean 45.5 ± 19.8 years old. All patients under went MRPA and MRPP and 3 patients were examined again after thrombolytic treatment. Five patients underwent pulmonary radionuclide perfusion imaging. Setting ROI in top, middle, bottom of lung area and abnormal area respectively, we detected signal intensity and time-signal curve to obtain the transformation rate of signal (TROS) during perfusion peak value. Results: In 14 pulmonary embolism patients, MRPA found 62 branches of pulmonary artery obstruction. Fifty-five abnormal pulmonary perfusion zones were found by MRPP, and the above results were very alike. The coincidence was 88.71%. In 14 cases, MRPP could show 25 subsegments lesion below segments. In 5 patients who had both results Of MRPP and ECT at the same time. MRPP shows 33 perfusion defect zones and 37 segments were found by ECT, the sensitivity was 89.19%. After thrombolytic treatment, both the status of the affected pulmonary artery improved markedly and perfusion defect zones reduced obviously in 3 cases by MRPP and MRPA. TROS in normal perfusion zones perfusion defect zones and low perfusion zones had significant difference (t=22.882, P<0.01). Conclusion: Contrast enhanced MR pulmonary perfusion can show both perfusion defect zones and low perfusion zones in pulmonary embolism. Time-signal curve can show the period of maximum no perfusion zones in pulmonary artery embolism zones. And the amplitude of fluctuation is small with miminum TROS. MRPP has significant values especially in showing pulmonary artery embolism in segments and subsegments. Using both MRPP and

  16. Perfusion lung scintigraphy in primary pulmonary hypertension

    International Nuclear Information System (INIS)

    Ogawa, Yoji; Nishimura, Tsunehiko; Kumita, Shin-ichirou; Hayashida, Kohei; Uehara, Toshiisa; Shimonagata, Tsuyoshi; Ohno, Akira

    1991-01-01

    Fifteen cases with primary pulmonary hypertension (PPH) were classified into two groups by using the perfusion lung scan pattern. Eight cases had multiple, small, ill-defined defects (mottled pattern), and remaining seven cases had no mottled pattern. These two groups were compared with mean pulmonary arterial pressure (mean PAP), right ventricular ejection fraction (RVEF), blood gas at room air (PaO 2 ), and alveolar-arterial O 2 difference (A-aDo 2 ). The cases with mottled pattern showed a significant increase in mean PAP. There were no significant differences in RVEF, PaO 2 , and A-aDo 2 , between the groups. The survival rate of the patients with mottled pattern was significantly lower than that without mottled pattern (p<0.05). We concluded that perfusion lung scan is very useful for evaluation of the prognosis in primary pulmonary hypertension. (author)

  17. Parent-Teacher Concordance in Rating Preschooler Difficulties in Behavioural and Cognitive Functioning and Their Dyadic Predicting of Fluid Intelligence

    Directory of Open Access Journals (Sweden)

    Orylska Anna

    2016-04-01

    Full Text Available Objective: Present research examined children’s behavioural and cognitive functioning by using data from a screening study based on reports given by parents and teachers, and investigated the strongest predictors of children’s fluid intelligence.

  18. Brain perfusion: computed tomography applications

    International Nuclear Information System (INIS)

    Miles, K.A.

    2004-01-01

    Within recent years, the broad introduction of fast multi-detector computed tomography (CT) systems and the availability of commercial software for perfusion analysis have made cerebral perfusion imaging with CT a practical technique for the clinical environment. The technique is widely available at low cost, accurate and easy to perform. Perfusion CT is particularly applicable to those clinical circumstances where patients already undergo CT for other reasons, including stroke, head injury, subarachnoid haemorrhage and radiotherapy planning. Future technical developments in multi-slice CT systems may diminish the current limitations of limited spatial coverage and radiation burden. CT perfusion imaging on combined PET-CT systems offers new opportunities to improve the evaluation of patients with cerebral ischaemia or tumours by demonstrating the relationship between cerebral blood flow and metabolism. Yet CT is often not perceived as a technique for imaging cerebral perfusion. This article reviews the use of CT for imaging cerebral perfusion, highlighting its advantages and disadvantages and draws comparisons between perfusion CT and magnetic resonance imaging. (orig.)

  19. Effects of angiotensin II and ionomycin on fluid and bicarbonate absorption in the rat proximal tubule

    International Nuclear Information System (INIS)

    Chatsudthipong, V.; Chan, Y.L.

    1986-01-01

    Microperfusion of proximal convoluted tubule(PCT) and peritubular capillaries was performed to examine the effects of angiotensin II(Ang II) and ionomycin on fluid and bicarbonate absorption. Bicarbonate was determined by microcalorimetry and C-14 inulin was used as a volume marker. The rates of bicarbonate absorption (JHCO 3 ) was 143 peq/min x mm and fluid absorption(Jv) was 2.70 nl/min x mm, when PCT and capillary perfusate contained normal Ringer solution. Addition of Ang II (10 -6 M) to the capillary perfusate caused reductions of JHCO 3 and Jv by 35%. A similar effect was observed when ionomycin was added to the capillary perfusate. Ang II antagonist, (Sar 1 , Ile 8 )-Angiotensin II(10 -6 M), completely blocked the inhibitory effect of Ang II on Jv and JHCO 3 . Removal of calcium from both luminal and capillary perfusate did not change the effect of Ang II on Jv and JHCO 3 . Our results indicate that Ang II inhibits the sodium-hydrogen exchanger in the proximal tubule via interacting with angiotensin receptor. The mechanism of Ang II action may involve mobilization of intracellular calcium

  20. Prediction of Liver Function by Using Magnetic Resonance-based Portal Venous Perfusion Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cao Yue, E-mail: yuecao@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Wang Hesheng [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Johnson, Timothy D. [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Pan, Charlie [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Hussain, Hero [Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Balter, James M.; Normolle, Daniel; Ben-Josef, Edgar; Ten Haken, Randall K.; Lawrence, Theodore S.; Feng, Mary [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2013-01-01

    Purpose: To evaluate whether liver function can be assessed globally and spatially by using volumetric dynamic contrast-enhanced magnetic resonance imaging MRI (DCE-MRI) to potentially aid in adaptive treatment planning. Methods and Materials: Seventeen patients with intrahepatic cancer undergoing focal radiation therapy (RT) were enrolled in institution review board-approved prospective studies to obtain DCE-MRI (to measure regional perfusion) and indocyanine green (ICG) clearance rates (to measure overall liver function) prior to, during, and at 1 and 2 months after treatment. The volumetric distribution of portal venous perfusion in the whole liver was estimated for each scan. We assessed the correlation between mean portal venous perfusion in the nontumor volume of the liver and overall liver function measured by ICG before, during, and after RT. The dose response for regional portal venous perfusion to RT was determined using a linear mixed effects model. Results: There was a significant correlation between the ICG clearance rate and mean portal venous perfusion in the functioning liver parenchyma, suggesting that portal venous perfusion could be used as a surrogate for function. Reduction in regional venous perfusion 1 month after RT was predicted by the locally accumulated biologically corrected dose at the end of RT (P<.0007). Regional portal venous perfusion measured during RT was a significant predictor for regional venous perfusion assessed 1 month after RT (P<.00001). Global hypovenous perfusion pre-RT was observed in 4 patients (3 patients with hepatocellular carcinoma and cirrhosis), 3 of whom had recovered from hypoperfusion, except in the highest dose regions, post-RT. In addition, 3 patients who had normal perfusion pre-RT had marked hypervenous perfusion or reperfusion in low-dose regions post-RT. Conclusions: This study suggests that MR-based volumetric hepatic perfusion imaging may be a biomarker for spatial distribution of liver function, which

  1. The zonal tidal effect on the variation in the rotation rate of the Earth with a fluid core I. Improvements on the theoretical formulae

    Science.gov (United States)

    Zhang, Han-Wei; Zheng, Yong; Du, Lan; Pan, Guan-Song

    The tidal variation in Earth's rotation rate is a periodical response to solar-lunar tide generating potential (TGP). In this article, the factor of the fluid core, which is related with the variation in the polar moment of inertia of the Earth, is considered and introduced distinctly into the theoretical formula of the variation in the Earth's rotational rate caused by lunar-solar tide-producing force based on the dynamics principle of the fluid core Earth. Different from previously work, some Doodson developments are given including the variation formulae of the Earth's rotational rate, LOD and UT1. The reasons are pointed why the moment of inertia for the scale should be the effective polar rotational moment of inertia of the mantle and the Love number should be the effective Love number of the mantle. It is also indicated that the factor of the fluid core is consistent with the effect of the effective Love number of the mantle due to fluid core.

  2. 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.)

  3. Quantitative lung perfusion evaluation using Fourier decomposition perfusion MRI.

    Science.gov (United States)

    Kjørstad, Åsmund; Corteville, Dominique M R; Fischer, Andre; Henzler, Thomas; Schmid-Bindert, Gerald; Zöllner, Frank G; Schad, Lothar R

    2014-08-01

    To quantitatively evaluate lung perfusion using Fourier decomposition perfusion MRI. The Fourier decomposition (FD) method is a noninvasive method for assessing ventilation- and perfusion-related information in the lungs, where the perfusion maps in particular have shown promise for clinical use. However, the perfusion maps are nonquantitative and dimensionless, making follow-ups and direct comparisons between patients difficult. We present an approach to obtain physically meaningful and quantifiable perfusion maps using the FD method. The standard FD perfusion images are quantified by comparing the partially blood-filled pixels in the lung parenchyma with the fully blood-filled pixels in the aorta. The percentage of blood in a pixel is then combined with the temporal information, yielding quantitative blood flow values. The values of 10 healthy volunteers are compared with SEEPAGE measurements which have shown high consistency with dynamic contrast enhanced-MRI. All pulmonary blood flow (PBF) values are within the expected range. The two methods are in good agreement (mean difference = 0.2 mL/min/100 mL, mean absolute difference = 11 mL/min/100 mL, mean PBF-FD = 150 mL/min/100 mL, mean PBF-SEEPAGE = 151 mL/min/100 mL). The Bland-Altman plot shows a good spread of values, indicating no systematic bias between the methods. Quantitative lung perfusion can be obtained using the Fourier Decomposition method combined with a small amount of postprocessing. Copyright © 2013 Wiley Periodicals, Inc.

  4. Protein profiling of cerebrospinal fluid

    DEFF Research Database (Denmark)

    Simonsen, Anja H

    2012-01-01

    The cerebrospinal fluid (CSF) perfuses the brain and spinal cord. CSF contains proteins and peptides important for brain physiology and potentially also relevant for brain pathology. Hence, CSF is the perfect source to search for new biomarkers to improve diagnosis of neurological diseases as well...

  5. Hepatic perfusion during hepatic artery infusion chemotherapy: Evaluation with perfusion CT and perfusion scintigraphy

    International Nuclear Information System (INIS)

    Miller, D.L.; Carrasquillo, J.A.; Lutz, R.J.; Chang, A.E.

    1989-01-01

    The standard method for the evaluation of hepatic perfusion during hepatic artery infusion (HAI) chemotherapy is planar hepatic artery perfusion scintigraphy (HAPS). Planar HAPS was performed with 2 mCi of [99mTc] macroaggregated albumin infused at 1 ml/min and compared with single photon emission CT (SPECT) HAPS and with a new study, CT performed during the slow injection of contrast material through the HAI catheter (HAI-CT). Thirteen patients underwent 16 HAI-CT studies, 14 planar HAPS studies, and 9 SPECT HAPS studies. In 13 of 14 studies (93%) HAI-CT and planar HAPS were in complete agreement as to the perfusion pattern of intrahepatic metastases and normal liver. In nine studies where all modalities were performed, the findings identified by HAI-CT and planar HAPS agreed in all cases, whereas the results of two SPECT scans disagreed with the other studies. With respect to perfusion of individual metastases, 14 of 14 HAI-CT studies, 12 of 13 planar HAPS studies, and 9 of 9 SPECT HAPS studies correctly demonstrated the perfusion status of individual lesions as indicated by the pattern of changes in tumor size determined on CT obtained before and after the perfusion studies. Hepatic artery infusion CT was superior for delineation of individual metastases, particularly small lesions, and for the evaluation of nonperfused portions of the liver. Planar HAPS detected extrahepatic perfusion in four patients, and this was not detected by HAI-CT. We conclude that HAI-CT and scintigraphy are complementary techniques. Hepatic artery infusion CT has advantages for the evaluation of intrahepatic perfusion, and planar HAPS is superior to HAI-CT for the detection of extrahepatic perfusion

  6. Role of myocardial perfusion SPECT in asymptomatic diabetic patients

    International Nuclear Information System (INIS)

    Cho, I.; Chun, K.; Won, K.; Lee, H.; Park, J.; Shin, D.; Kim, Y.; Shim, B.; Lee, J.

    2002-01-01

    Purpose: It is important that early diagnosis and treatment of coronary artery disease in diabetic patients, but there are few reports on the prevalence of stress-induced myocardial perfusion abnormalities and the rates of cardiac event in patients with type 2 diabetes. We evaluated the scan findings on gated myocardial perfusion SPECT in asymptomatic diabetic patients. Methods: We performed pharmacological stress test and gated perfusion SPECT in 69 diabetic patients without cardiovascular symptom (mean age: 65 year, male 31 and female 38). Patients underwent two-day imaging protocol and stress study was performed injection of Tc-99m MIBI during adenosine infusion. We followed up these patients by reviewing medical records. Results: Fifty-two of 69 patients (74.5%) showed normal scan findings and 17 patients (24.6%) showed reversible or fixed perfusion defects. Three of 52 patients with normal scan findings showed decreased LV ejection fraction and decreased wall motion. Twenty-three patients with normal scan findings were possible to follow up for more than 1yr (mean time: 18.3±3.3 mo.) and they all had no cardiac event. Three patients with reversible perfusion defects were performed coronary angioplasty. Conclusion: Myocardial perfusion SPECT is a noninvasive method and maybe useful in early diagnosis and predicting prognosis in diabetic patients

  7. Goal-directed-perfusion in neonatal aortic arch surgery.

    Science.gov (United States)

    Cesnjevar, Robert Anton; Purbojo, Ariawan; Muench, Frank; Juengert, Joerg; Rueffer, André

    2016-07-01

    Reduction of mortality and morbidity in congenital cardiac surgery has always been and remains a major target for the complete team involved. As operative techniques are more and more standardized and refined, surgical risk and associated complication rates have constantly been reduced to an acceptable level but are both still present. Aortic arch surgery in neonates seems to be of particular interest, because perfusion techniques differ widely among institutions and an ideal form of a so called "total body perfusion (TBP)" is somewhat difficult to achieve. Thus concepts of deep hypothermic circulatory arrest (DHCA), regional cerebral perfusion (RCP/with cardioplegic cardiac arrest or on the perfused beating heart) and TBP exist in parallel and all carry an individual risk for organ damage related to perfusion management, chosen core temperature and time on bypass. Patient safety relies more and more on adequate end organ perfusion on cardiopulmonary bypass, especially sensitive organs like the brain, heart, kidney, liver and the gut, whereby on adequate tissue protection, temperature management and oxygen delivery should be visualized and monitored.

  8. Myocardial perfusion SPECT imaging in patients with myocardial bridging

    International Nuclear Information System (INIS)

    Fang Wei; Qiu Hong; Yang Weixian; Wang Feng; He Zuoxiang

    2008-01-01

    Objective: Stress myocardial perfusion SPECT imaging was used to assess myocardial ischemia in patients with myocardial bridging. Methods: Ninety-six patients with myocardial bridging of the left anterior descending artery documented by coronary angiography were included in this study. All under- went exercise or pharmacological stress myocardial perfusion SPECT assessing myocardial ischemia. None had prior myocardial infarction. One year follow-up by telephone interview was performed in all patients. Results The mean stenotic severity of systolic phase on angiography was (65 ± 19)%. In the SPECT study, 20 of 96 (20.8%) patients showed abnormal perfusion. This percentage was significantly higher than that of stress electrocardiogram (ECG). The higher positive rate of SPECT perfusion images was showed in the group of patients with severe systolic narrowing (≥75%) than that with mild-to-moderate systolic narrowing (50% vs 6.3%, P<0.001). The prevalence of abnormal image was significantly higher in ELDERLY PEOPLE; patients with STT change on rest ECG than in those with normal rest ECG (54.2% vs 9.7%, P<0.001). During follow-up, one patient with abnormal SPECT perfusion image sustained angina and accepted percutaneous coronary intervention, and no cardiac event occurred in patients with normal images. Conclusions: Stress myocardial perfusion SPECT imaging can be used effectively for assessing myocardial ischemia and has potential prognostic value for patients with myocardial bridging. (authors)

  9. Measurement of single-kidney glomerular filtration function from magnetic resonance perfusion renography

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Meiying; Cheng, Yingsheng [Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Shanghai 200233 (China); Zhao, Binghui, E-mail: binghuizhao@163.com [Department of Radiology, Shanghai Tenth People' s Hospital, Tongji University, Shanghai 200072 (China)

    2015-08-15

    Highlights: • MRPR monitors the transit of contrast material through nephron. • MRPR could reveal renal physiological characteristics in quality and quantity. • This review outlines the basics and future challenges of DCE MRPR. - Abstract: Glomerular filtration rate (GFR) describes the flow rate of filtered fluid through the kidney, and is considered to be the reference standard in the evaluation of renal function. There are many ways to test the GFR clinically, such as serum creatinine concentration, blood urea nitrogen and SPECT renography, however, they’re all not a good standard to evaluate the early damage of renal function. In recent years, the improvement of MRI hardware and software makes it possible to reveal physiological characteristics such as renal blood flow or GFR by dynamic contrast enhancement magnetic resonance perfusion renography (DEC MRPR). MRPR is a method used to monitor the transit of contrast material, typically a gadolinium chelate, through the renal cortex, the medulla, and the collecting system. This review outlines the basics of DCE MRPR included acquisition of dynamic MR perfusion imaging, calculation of the contrast concentration from signal intensity and compartment models, and some challenges of MRPR method faced in prospective clinical application.

  10. Water permeability of acinar cell membranes in the isolated perfused rabbit mandibular salivary gland.

    Science.gov (United States)

    Steward, M C; Seo, Y; Rawlings, J M; Case, R M

    1990-01-01

    1. The diffusive water permeability of epithelial cell membranes in the perfused rabbit mandibular salivary gland was measured at 37 degrees C by a 1H nuclear magnetic resonance relaxation method using an extracellular relaxation reagent, gadolinium diethylenetriaminepentaacetic acid (Gd(DTPA)). 2. In glands perfused with a HEPES-buffered solution containing 10 mmol l-1 Gd(DTPA), the spin-lattice (T1) relaxation of the water protons showed two exponential components. The water compartment responsible for the slower component corresponded in magnitude to 71 +/- 5% of the wet weight of the gland, and was attributed to the exchangeable intracellular water of the acinar cells. 3. The rate constant for water efflux from the cells was estimated to be 4.1 +/- 0.1 s-1 which would be consistent with a diffusive membrane permeability (Pd) of approximately 3 x 10(-3) cm s-1. Stimulation with acetylcholine (10(-6) mol l-1) did not cause any detectable change in membrane water permeability. 4. Since the basolateral membrane probably provides the main pathway for water efflux, the osmotic water permeability of this barrier (expressed per gland) was estimated to be less than 6.2 cm3 s-1. This would be insufficient to account for the generation of a near-isosmotic fluid at the flow rates observed during secretion, and suggests that a substantial fraction of the flow of water occurs via a paracellular route. PMID:1966053

  11. Experimental determination of growth rate effect on U 6+ and Mg 2+ partitioning between aragonite and fluid at elevated U 6+ concentration

    Science.gov (United States)

    Gabitov, R. I.; Gaetani, G. A.; Watson, E. B.; Cohen, A. L.; Ehrlich, H. L.

    2008-08-01

    Results are reported from an experimental study in which the partitioning of U and Mg between aragonite and an aqueous solution were determined as a function of crystal growth rate. Crystals, identified as aragonite by X-ray diffractometry and micro-Raman spectroscopy, were grown by diffusion of CO 2 from an ammonium carbonate source into a calcium-bearing solution at temperatures of 22 and 53 °C. Hemispherical bundles (spherulites) of aragonite crystals were produced, the growth rates of which decreased monotonically from the spherulite interiors to the edges and thus provide the opportunity to examine the influence of growth rate on crystal composition. Element concentration ratios were measured using electron microprobe (EMP) and fluid composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS) and atomic absorption (AA). Growth rates were determined directly by addition of a Dy spike to the fluid during the experiment that was subsequently located in an experimentally precipitated spherulite using secondary ion mass spectrometry (SIMS). At 22 °C both U/Ca and Mg/Ca partition coefficients exhibited a strong growth rate dependence when crystal growth rates were low, and became independent of growth rate when crystal growth rates were high. The U/Ca ratios in aragonite increase between 22 and 53 °C; in contrast Mg/Ca ratios show inverse dependence on temperature.

  12. Corrosion rate of steel embedded in blended Portland and fluid catalytic cracking catalyst residue (FC3R cement mortars

    Directory of Open Access Journals (Sweden)

    Payá, J.

    2008-12-01

    Full Text Available This paper reports on a study of the corrosion levels in steel bars embedded in mortars made with a blend of Portland cement and (0-20% spent fluid catalytic cracking catalyst residue (FC3R, with a variable (0.3-0.7 water/binder (w/b ratio. The specimens were stored in the following conditions: relative humidity of 40, 80 or 100% and CO2 concentrations of 5 and 100%. The steel corrosion rate was measured with polarization resistance techniques. In the absence of aggressive agents, the steel was found to remain duly passivated in mortars with an FC3R content of up to 15% under all the conditions of relative humidity tested. The reinforcement corrosion level in mortars with a w/b ratio of 0.3 and 15% FC3R subjected to accelerated carbonation was similar to the level observed in the unblended Portland cement control mortar.En este trabajo se ha estudiado el nivel de corrosión de barras de acero embebidas en morteros de cemento Portland con relación agua/material cementante (a/mc variable (0,3-0,7, en los que parte del cemento (0-20% se sustituyó por catalizador de craqueo usado (FC3R. Las condiciones de conservación de las probetas elaboradas fueron las siguientes: distintas humedades relativas (40, 80 y 100% y dos concentraciones de CO2 (5 y 100%. La velocidad de corrosión de los aceros se midió mediante la técnica de resistencia de polarización. Se ha podido determinar que, bajo las distintas condiciones de humedad relativa y ausencia de agresivo, los aceros se mantuvieron correctamente pasivados en los morteros con contenidos de FC3R de hasta el 15%. El nivel de corrosión que presenta el refuerzo embebidos en morteros con sustitución de un 15% de cemento por FC3R y relación a/mc 0,3, al ser sometidos a un proceso de carbonatación acelerada, era muy similar al mostrado por el mortero patrón, sin FC3R.

  13. Regional cerebral perfusion in cardiovascular reflex syncope

    International Nuclear Information System (INIS)

    Toeyry, J.P.; Kuikka, J.T.; Laensimies, E.A.

    1997-01-01

    Little is known about the regional cerebral perfusion in subjects with presyncope or syncope, and the impact that autonomic nervous dysfunction has on it. Seven subjects with cardiovascular vasodepressor reflex syncope were studied. A baseline test was performed with the patients standing in the 70 upright position, while the passive head-up tilt table test with and without isoprenaline infusion was employed for provocation. Regional cerebral perfusion was assessed by means of single-photon emission tomography with technetium-99m labelled V-oxo-1,2-N,N 1 -ethylenedylbis-l-cysteine diethylester (baseline, and during blood pressure decline in the provocation test) and the autonomic nervous function by means of spectral analysis of heart rate variability (baseline, and before blood pressure decline in the provocation test). Every subject showed an abrupt decline in blood pressure in the provocation test (five with presyncope and two with syncope). The systolic and diastolic blood pressures decreased significantly (P<0.001) between the baseline and the provocation study time points (radiopharmaceutical injection and lowest systolic blood pressure). Mean cerebral perfusion as average count densities decreased upon provocation as compared with baseline (190±63 vs 307±90 counts/voxel, respectively, P=0.013). Hypoperfusion was most pronounced in the frontal lobe. These results suggest that cerebral perfusion decreases markedly during presyncope or syncope with systemic blood pressure decline in subjects with cardiovascular vasodepressor syncope. Furthermore, the autonomic nervous function remains unchanged before the systemic blood pressure decline. (orig.). With 3 figs., 2 tabs

  14. Fluid dynamics of dilatant fluid

    DEFF Research Database (Denmark)

    Nakanishi, Hiizu; Nagahiro, Shin-ichiro; Mitarai, Namiko

    2012-01-01

    of the state variable, we demonstrate that the model can describe basic features of the dilatant fluid such as the stress-shear rate curve that represents discontinuous severe shear thickening, hysteresis upon changing shear rate, and instantaneous hardening upon external impact. An analysis of the model...

  15. Production of acetone and conversion of acetone to acetate in the perfused rat liver

    International Nuclear Information System (INIS)

    Gavino, V.C.; Somma, J.; Philbert, L.; David, F.; Garneau, M.; Belair, J.; Brunengraber, H.

    1987-01-01

    The utilization of millimolar concentrations of [2- 14 C]acetone and the production of acetone from acetoacetate were studied in perfused livers from 48-h starved rats. We devised a procedure for determining, in a perfused liver system, the first-order rate constant for the decarboxylation of acetoacetate (0.29 +/- 0.09 h-1, S.E., n = 8). After perfusion of livers with [2- 14 C]acetone, labeled acetate was isolated from the perfusion medium and characterized as [1- 14 C]acetate. No radioactivity was found in lactate or 3-hydroxybutyrate. After 90 min of perfusion with [2- 14 C]acetone, the specific activity of acetate was 30 +/- 4% (n = 13) of the initial specific activity of acetone. We conclude that, in perfused livers from 2-day starved rats, acetone metabolism occurs for the most part via free acetate

  16. Comparing kidney perfusion using noncontrast arterial spin labeling MRI and microsphere methods in an interventional swine model.

    Science.gov (United States)

    Artz, Nathan S; Wentland, Andrew L; Sadowski, Elizabeth A; Djamali, Arjang; Grist, Thomas M; Seo, Songwon; Fain, Sean B

    2011-02-01

    The purpose of this study was to assess the ability of a flow-sensitive alternating inversion recovery-arterial spin labeling (FAIR-ASL) technique to track renal perfusion changes during pharmacologic and physiologic alterations in renal blood flow using microspheres as a gold standard. Fluorescent microsphere and FAIR-ASL perfusion were compared in the cortex of the kidney for 11 swine across 4 interventional time points: (1) under baseline conditions, (2) during an acetylcholine and fluid bolus challenge to increase perfusion, (3) initially after switching to isoflurane anesthesia, and (4) after 2 hours of isoflurane anesthesia. In 10 of the 11 swine, a bag of ice was placed on the hilum of 1 kidney at the beginning of isoflurane administration to further reduce perfusion in 1 kidney. Both ASL and microspheres tracked the expected cortical perfusion changes (P values were systematically lower compared with microsphere perfusion. Very good correlation (r = 0.81, P values in the expected physiologic range (microsphere perfusion values saturated for perfusion >550 mL/min/100 g. Cortical perfusion measured with ASL correlated with microspheres and reliably detected changes in renal perfusion in response to physiologic challenge.

  17. Clinical evaluation of non-invasive perfusion-weighted MRI

    International Nuclear Information System (INIS)

    Takasu, Miyuki

    2000-01-01

    A spin labeling method to measure cerebral blood flow without a contrast medium was developed and applied clinically to obtain a non-invasive perfusion-weighted image. The purpose of this study is to compare the non-invasive perfusion-weighted image using FAIR with the well-established PWI using a bolus injection of Gd-DTPA. Of 41 lesions which revealed decreased perfusion, 13 were shown to be low signal intensity areas on FAIR. Therefore, detection rate of FAIR for hypoperfusion was 32%. Of 8 lesions which revealed increased perfusion, 7 demonstrated high intensity on FAIR. Therefore, detection rate of FAIR for hyperperfusion was 88%. Seven lesions were found to have a mean pixel value of zero on PWI. Of these lesions, 5 lesions could be detected as high signal intensity area on FAIR. The rCBV- and rCBF index ratios of hypoperfused lesions detected on FAIR were significantly lower than those of lesions which were not detected on FAIR (p=0.007, p=0.01). As concerns the lesions detected of FAIR, there were positive correlation between rCBV- or rCBF index ratio and FAIR signal ratio (rCBV ratio: ρ=0.873, p=0.0002, rCBF index ratio: ρ=0.858, p=0.0003). FAIR is valuable clinical tool to detect perfusion abnormality semi-quantitatively without contrast medium, although it showed relatively low detection rate for hypoperfused lesions. (author)

  18. Feasibility of high-resolution quantitative perfusion analysis in patients with heart failure.

    Science.gov (United States)

    Sammut, Eva; Zarinabad, Niloufar; Wesolowski, Roman; Morton, Geraint; Chen, Zhong; Sohal, Manav; Carr-White, Gerry; Razavi, Reza; Chiribiri, Amedeo

    2015-02-12

    Cardiac magnetic resonance (CMR) is playing an expanding role in the assessment of patients with heart failure (HF). The assessment of myocardial perfusion status in HF can be challenging due to left ventricular (LV) remodelling and wall thinning, coexistent scar and respiratory artefacts. The aim of this study was to assess the feasibility of quantitative CMR myocardial perfusion analysis in patients with HF. A group of 58 patients with heart failure (HF; left ventricular ejection fraction, LVEF ≤ 50%) and 33 patients with normal LVEF (LVEF >50%), referred for suspected coronary artery disease, were studied. All subjects underwent quantitative first-pass stress perfusion imaging using adenosine according to standard acquisition protocols. The feasibility of quantitative perfusion analysis was then assessed using high-resolution, 3 T kt perfusion and voxel-wise Fermi deconvolution. 30/58 (52%) subjects in the HF group had underlying ischaemic aetiology. Perfusion abnormalities were seen amongst patients with ischaemic HF and patients with normal LV function. No regional perfusion defect was observed in the non-ischaemic HF group. Good agreement was found between visual and quantitative analysis across all groups. Absolute stress perfusion rate, myocardial perfusion reserve (MPR) and endocardial-epicardial MPR ratio identified areas with abnormal perfusion in the ischaemic HF group (p = 0.02; p = 0.04; p = 0.02, respectively). In the Normal LV group, MPR and endocardial-epicardial MPR ratio were able to distinguish between normal and abnormal segments (p = 0.04; p = 0.02 respectively). No significant differences of absolute stress perfusion rate or MPR were observed comparing visually normal segments amongst groups. Our results demonstrate the feasibility of high-resolution voxel-wise perfusion assessment in patients with HF.

  19. Hydrogen ion changes and contractile behavior in the perfused rat heart

    NARCIS (Netherlands)

    Cingolani, H.E.; Maas, A.H.J.; Zimmerman, A.N.E.; Meijler, F.L.

    1975-01-01

    The effect of acid-base alterations was analyzed using isolated rat hearts perfused at constant coronary perfusion pressure, and stimulated to contract at constant rate. The amount of shortening in the major axis and its derivative were measured to assess myocardial contractility. Both the

  20. A pump-free microfluidic 3D perfusion platform for the efficient differentiation of human hepatocyte-like cells.

    Science.gov (United States)

    Ong, Louis Jun Ye; Chong, Lor Huai; Jin, Lin; Singh, Pawan Kumar; Lee, Poh Seng; Yu, Hanry; Ananthanarayanan, Abhishek; Leo, Hwa Liang; Toh, Yi-Chin

    2017-10-01

    The practical application of microfluidic liver models for in vitro drug testing is partly hampered by their reliance on human primary hepatocytes, which are limited in number and have batch-to-batch variation. Human stem cell-derived hepatocytes offer an attractive alternative cell source, although their 3D differentiation and maturation in a microfluidic platform have not yet been demonstrated. We develop a pump-free microfluidic 3D perfusion platform to achieve long-term and efficient differentiation of human liver progenitor cells into hepatocyte-like cells (HLCs). The device contains a micropillar array to immobilize cells three-dimensionally in a central cell culture compartment flanked by two side perfusion channels. Constant pump-free medium perfusion is accomplished by controlling the differential heights of horizontally orientated inlet and outlet media reservoirs. Computational fluid dynamic simulation is used to estimate the hydrostatic pressure heads required to achieve different perfusion flow rates, which are experimentally validated by micro-particle image velocimetry, as well as viability and functional assessments in a primary rat hepatocyte model. We perform on-chip differentiation of HepaRG, a human bipotent progenitor cell, and discover that 3D microperfusion greatly enhances the hepatocyte differentiation efficiency over static 2D and 3D cultures. However, HepaRG progenitor cells are highly sensitive to the time-point at which microperfusion is applied. Isolated HepaRG cells that are primed as static 3D spheroids before being subjected to microperfusion yield a significantly higher proportion of HLCs (92%) than direct microperfusion of isolated HepaRG cells (62%). This platform potentially offers a simple and efficient means to develop highly functional microfluidic liver models incorporating human stem cell-derived HLCs. Biotechnol. Bioeng. 2017;114: 2360-2370. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  1. Differential physiologic effects of perfusion of scala tympani versus scala vestibuli in the ischemic cochlea.

    Science.gov (United States)

    Kobayashi, T; Rokugo, M; Takasaka, T; Thalmann, R

    1993-07-01

    The effectiveness of perilymphatic perfusion with oxygenated artificial media upon the endocochlear potential (EP) was measured during systemic ischemia in the guinea pig. Differences in the effects of perfusion of the two perilymphatic scalae were determined. Perfusion of scala vestibuli with oxygenated artificial perilymph at a high flow rate resulted in complete recovery of the EP to the pre-ischemic level, whereas perfusion of scala tympani with the same medium was unable to effect complete recovery. The recovery obtained by perfusion of scala tympani was about half that obtained of scala vestibuli. The pO2 in scala media was measured during perfusion by means of oxygen-sensitive microelectrodes. perfusion of scala vestibuli led to an approximately two-fold higher pO2 in scala media than perfusion of scala tympani. During perfusion, the pO2 in scala media varied dependent upon depth of electrode insertion, with a gradient decreasing toward the stria vascularis, a direction opposite to that seen under normal metabolic conditions. These findings suggest that, in the ischemic cochlea, oxygen enters scala media more easily from scala vestibuli across Reissner's membrane than from scala tympani via the basilar membrane/organ of Corti complex.

  2. Whole Ovine Ovaries as a Model for Human: Perfusion with Cryoprotectants In Vivo and In Vitro

    Directory of Open Access Journals (Sweden)

    Vladimir Isachenko

    2014-01-01

    Full Text Available These experiments were performed to test the perfusion of ovine as a model for human ovaries by cryoprotectants in vivo at high temperature when the permeability of capillaries is high and when blood is insensibly replaced by the solution of cryoprotectants. By our hypothetical supposition, ovaries could be saturated by cryoprotectants before their surgical removal. The objective was to examine the effectiveness of perfusion of ovine ovaries with vascular pedicle in vivo and in vitro. Arteria ovarica was cannuled and ovaries were perfused by Leibovitz L-15 medium + 100 IU/mL heparin + 5% bovine calf serum + 6% dimethyl sulfoxide + 6% ethylene glycol + 0.15 M sucrose + Indian ink in vivo and in vitro. In the first and second cycle of experiments, ovaries (n=13 and n=23 were perfused in vivo and in vitro, respectively, during 60 min with the rate of perfusion 50 mL/h (0.8 mL/min. It was established with in vivo perfusion that only about 10% of ovarian tissues were perfused due to an appearance of multiple anastomoses when the perfusion medium goes from arteria ovarica to arteria uterina without inflow into the ovaries. It was concluded that in vitro perfusion of ovine intact ovaries with vascular pedicle by freezing medium is more effective than this manipulation performed in vivo.

  3. Dynamic CT myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Caruso, Damiano; Eid, Marwen; Schoepf, U. Joseph; Jin, Kwang Nam; Varga-Szemes, Akos; Tesche, Christian; Mangold, Stefanie

    2016-01-01

    Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  4. Dynamic CT myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Caruso, Damiano [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiological Sciences, Oncological and Pathological Sciences, University of Rome “Sapienza”, Latina (Italy); Eid, Marwen [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States); Jin, Kwang Nam [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul (Korea, Republic of); Varga-Szemes, Akos [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Tesche, Christian [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich (Germany); Mangold, Stefanie [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen (Germany); and others

    2016-10-15

    Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  5. Lung perfusion scintigraphy by SPECT

    International Nuclear Information System (INIS)

    Hirayama, Takanobu

    1990-01-01

    The initial study reports the characteristic performance using lung segmental phantom filled in Tc-99m pertechnetate. To evaluate the segmental defect in lung perfusion scintigraphy, we applied Bull's-eye analysis in addition to planar image set. Bull's-eye analysis especially facilitated the interpretation in both middle and lower lobes. Subsequently, to evolute the clinical application of Bull's-eye analysis, pulmonary scintigraphy was performed on 10 normal subjects and 60 patients with several pulmonary diseases. Of interest, Bull's-eye analysis, however, encouraged the interpretation in both lower lobes. To calculate the extention and severity of perfusion defect, the present study describes Bull's-eye analysis. Quantitative scoring showed higher in patients with lung cancer than those with pulmonary tuberculosis. The present study focus that Bull's-eye analysis can be useful for evaluating perfusion in patients with a couple of pulmonary diseases. (author)

  6. Plasma-to-ascitic fluid transport rate of albumin in patients with decompensated cirrhosis. Relation to intraperitoneal albumin

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Ring-Larsen, H; Lassen, N A

    1983-01-01

    was on the average 0.22 of that of plasma and directly correlated to the plasma concentration (rlin = 0.68, P less than 0.01). The hydrostatic pressure difference across the splanchnic microvasculature (assessed as wedged hepatic vein minus inferior vena caval pressure) was directly correlated to the effective...... (plasma minus ascitic fluid) oncotic pressure (rlin = 0.74, P less than 0.001) but significantly higher than that (P less than 0.005), indicating a 'non-equilibrium' in the splanchnic Starling forces. The results point to a multivariate genesis and perpetuation of cirrhotic ascites as laid down...

  7. A Pilot Trial of Pioglitazone HCl and Tretinoin in ALS: Cerebrospinal Fluid Biomarkers to Monitor Drug Efficacy and Predict Rate of Disease Progression

    Directory of Open Access Journals (Sweden)

    Todd D. Levine

    2012-01-01

    Full Text Available Objectives. To determine if therapy with pioglitazone HCl and tretinoin could slow disease progression in patients with ALS. Levels of tau and pNFH in the cerebrospinal fluid were measured to see if they could serve as prognostic indicators. Methods. 27 subjects on stable doses of riluzole were enrolled. Subjects were randomized to receive pioglitazone 30 mg/d and tretinoin 10 mg/BID for six months or two matching placebos. ALSFRS-R scores were followed monthly. At baseline and at the final visit, lumbar punctures (LPs were performed to measure cerebrospinal fluid (CSF biomarker levels. Results. Subjects treated with tretinoin, pioglitazone, and riluzole had an average rate of decline on the ALSFRS-R scale of −1.02 points per month; subjects treated with placebo and riluzole had a rate of decline of -.86 (P=.18. Over six months of therapy, CSF tau levels decreased in subjects randomized to active treatment and increased in subjects on placebo. Further higher levels of pNF-H at baseline correlated with a faster rate of progression. Conclusion. ALS patients who were treated with tretinoin and pioglitazone demonstrated no slowing on their disease progression. Interestingly, the rate of disease progression was strongly correlated with levels of pNFH in the CSF at baseline.

  8. Dynamic CT myocardial perfusion imaging identifies early perfusion abnormalities in diabetes and hypertension : Insights from a multicenter registry

    NARCIS (Netherlands)

    Vliegenthart, Rozemarijn; De Cecco, Carlo N.; Wichmann, Julian L.; Meinel, Felix G.; Pelgrim, Gert Jan; Tesche, Christian; Ebersberger, Ullrich; Pugliese, Francesca; Bamberg, Fabian; Choe, Yeon Hyeon; Wang, Yining; Schoepf, U. Joseph

    2016-01-01

    Background: To identify patients with early signs of myocardial perfusion reduction, a reference base for perfusion measures is needed. Objective: To analyze perfusion parameters derived from dynamic computed tomography perfusion imaging (CTPI) in patients with suspected coronary artery disease

  9. Automatic assessment of cardiac perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur; Stegmann, Mikkel Bille; Larsson, Henrik B.W.

    2004-01-01

    In this paper, a method based on Active Appearance Models (AAM) is applied for automatic registration of myocardial perfusion MRI. A semi-quantitative perfusion assessment of the registered image sequences is presented. This includes the formation of perfusion maps for three parameters; maximum up...

  10. Detachably assembled microfluidic device for perfusion culture and post-culture analysis of a spheroid array.

    Science.gov (United States)

    Sakai, Yusuke; Hattori, Koji; Yanagawa, Fumiki; Sugiura, Shinji; Kanamori, Toshiyuki; Nakazawa, Kohji

    2014-07-01

    Microfluidic devices permit perfusion culture of three-dimensional (3D) tissue, mimicking the flow of blood in vascularized 3D tissue in our body. Here, we report a microfluidic device composed of a two-part microfluidic chamber chip and multi-microwell array chip able to be disassembled at the culture endpoint. Within the microfluidic chamber, an array of 3D tissue aggregates (spheroids) can be formed and cultured under perfusion. Subsequently, detailed post-culture analysis of the spheroids collected from the disassembled device can be performed. This device facilitates uniform spheroid formation, growth analysis in a high-throughput format, controlled proliferation via perfusion flow rate, and post-culture analysis of spheroids. We used the device to culture spheroids of human hepatocellular carcinoma (HepG2) cells under two controlled perfusion flow rates. HepG2 spheroids exhibited greater cell growth at higher perfusion flow rates than at lower perfusion flow rates, and exhibited different metabolic activity and mRNA and protein expression under the different flow rate conditions. These results show the potential of perfusion culture to precisely control the culture environment in microfluidic devices. The construction of spheroid array chambers allows multiple culture conditions to be tested simultaneously, with potential applications in toxicity and drug screening. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The zonal tidal effect on the variation in the rotation rate of the Earth with a fluid core II. Numerical calculation and comparisons

    Science.gov (United States)

    Zhang, Han-Wei; Zheng, Yong; Du, Lan; Pan, Guan-Song

    The tidal variation in Earth rotation rate is a periodical response to solar-lunar tide generating potential (TGP). Some theoretical formulae are given here based on Doodson development of TGP including the variations in Earth rotation rate, LOD and UT1. Finally the zonal tidal effect on the variation in the fluid core Earth rotation rate is calculated according to the formula deduced by Xi Qinwen (1995). The calculation shows that the results in this paper are well consistent with the ones in IERS (96), which indicates the correctness of the theoretical formula we deduced. It is also shown that the effects from the high frequency parts are relatively small, within the observing precision so far; relatively large effects due to the lower parts, which should be able to be seperated from the observed data, are actually difficult to make because of the influence from some non-tidal factors as well as short time span data.

  12. Prognostic Value of Normal Perfusion but Impaired Left Ventricular Function in the Diabetic Heart on Quantitative Gated Myocardial Perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hwanjeong; Choi, Sehun; Han, Yeonhee [Research Institute of Chonbuk National Univ. Medical School and Hospitial, Jeonju (Korea, Republic of); Lee, Dong Soo; Lee, Hoyoung; Chung, Junekey [Seoul National Univ., Seoul (Korea, Republic of)

    2013-09-15

    This study aimed at identifying the predictive parameters on quantitative gated myocardial perfusion single-photon emission computed tomography (QG-SPECT) in diabetic patients with normal perfusion but impaired function. Methods Among the 533 consecutive diabetic patients, 379 patients with normal perfusion on rest Tl-201/dipyridamole-stress Tc-{sup 99m} sestamibi Gated SPECT were enrolled. Patients were grouped into those with normal post-stress left ventricular function (Group I) and those with impaired function (EF <50 or impaired regional wall motion, Group II). We investigated cardiac events and cause of death by chart review and telephone interview. Survival analysis and Cox proportional hazard model analysis were performed. Between the Group I and II, cardiac events as well as chest pain symptoms, smoking, diabetic complications were significantly different (P<0.05). On survival analysis, event free survival rate in Group II was significantly lower than in Group I (P=0.016). In univariate Cox proportional hazard analysis on overall cardiac event, Group (II over I), diabetic nephropathy, summed motion score (SMS), summed systolic thickening score (STS), numbers of abnormal segmental wall motion and systolic thickening predicted more cardiac events (P<0.05). Multivariate analysis showed that STS was the only independent predictor cardiac event. The functional parameter, especially summed systolic thickening score on QG-SPECT had prognostic values, despite normal perfusion, in predicting cardiac events in diabetic patients, and QG-SPECT provides clinically useful risk stratification in diabetic patients with normal perfusion.

  13. Feasibility study of the dissolution rates of uranium ore dust, uranium concentrates and uranium compounds in simulated lung fluid

    International Nuclear Information System (INIS)

    Robertson, R.

    1986-01-01

    A flow-through apparatus has been devised to study the dissolution in simulated lung fluid of aerosol materials associated with the Canadian uranium industry. The apparatus has been experimentally applied over 16 day extraction periods to approximately 2g samples of < 38um and 53-75um particle-size fractions of both Elliot Lake and Mid-Western uranium ores. The extraction of uranium-238 was in the range 24-60% for these samples. The corresponding range for radium-226 was 8-26%. Thorium-230, lead-210, polonium-210, and thorium-232 were not significantly extracted. It was incidentally found that the elemental composition of the ores studied varies significantly with particle size, the radionuclide-containing minerals and several extractable stable elements being concentrated in the smaller size fraction. Samples of the refined compounds uranium dioxide and uranium trioxide were submitted to similar 16 day extraction experiments. Approximately 0.5% of the uranium was extracted from a 0.258g sample of unsintered (fluid bed) uranium dioxide of particle size < 38um. The corresponding figure for a 0.292g sample of uranium trioxide was 97%. Two aerosol samples on filters were also studied. Of the 88ug uranium initially measured on stage 2 of a cascade impactor sample collected from the yellow cake packing area of an Elliot Lake mill, essentially 100% was extracted over a 16 day period. The corresponding figure for an open face filter sample collected in a fuel fabrication plant and initially measured at 288ug uranium was approximately 3%. Recommendations are made with regard to further work of a research nature which would be useful in this area. Recommendations are also made on sampling methods, analytical methods and extraction conditions for various aerosols of interest which are to be studied in a work of broader scope designed to yield meaningful data in connection with lung dosimetry calculations

  14. Compartmented pyruvate in perfused working heart

    International Nuclear Information System (INIS)

    Buenger, R.

    1985-01-01

    Pyruvate compartmentation and lactate dehydrogenase (LDH) were studied in isolated perfused working guinea pig hearts. The mean intracellular pyruvate (Pyr) contents increased with perfusate Pyr (0-2 mM) but varied only slightly with glucose (0-10 mM) and additional insulin (0.04-5 U/l), respectively. With 5-10 mM glucose plus 5 U/l insulin, but not with Pyr or lactate (Lac) as substrates, a near equilibrium between the LDH and the glycerol-3-phosphate dehydrogenase seemed to exist. Evidence for an inhibitory effect of Pyr on the activity of the LDH system of the perfused hearts was not obtained. With [U- 14 C]glucose as sole substrate, the specific activity of coronary venous Lac was near half that of precursor glucose. 14 CO 2 production was thus in quantitative agreement with rates of pyruvate oxidation that were determined as glucose uptake minus (Pyr + Lac) release. In contrast, with 0.2 mM [1- 14 C]Pyr plus 5 mM glucose, the ratio of 14 CO 2 production to specific activity of Lac overestimated Pyr oxidation judged from myocardial substrate balances and O 2 uptake, respectively; here, at least three pools of [ 14 C]HCO-3 and [ 14 C]lac, respectively, were kinetically demonstrable during washout of trace amounts of 14 C-labeled Pyr. Evidently, the specific activity of Lac was equivalent to that of mitochondrial oxidized Pyr provided [ 14 C]glucose was the sole or major precursor of cellular pyruvate. However, exogenously applied [1- 14 C]Pyr of high specific activity seemed to induce intracellular formation of both a highly and lowly labeled Pyr; the latter Pyr compartment did not seem in ready equilibrium with the cell physiologically prevailing highly labeled Pyr pool

  15. Controlling the Release of Indomethacin from Glass Solutions Layered with a Rate Controlling Membrane Using Fluid-Bed Processing. Part 1: Surface and Cross-Sectional Chemical Analysis.

    Science.gov (United States)

    Dereymaker, Aswin; Scurr, David J; Steer, Elisabeth D; Roberts, Clive J; Van den Mooter, Guy

    2017-04-03

    Fluid bed coating has been shown to be a suitable manufacturing technique to formulate poorly soluble drugs in glass solutions. Layering inert carriers with a drug-polymer mixture enables these beads to be immediately filled into capsules, thus avoiding additional, potentially destabilizing, downstream processing. In this study, fluid bed coating is proposed for the production of controlled release dosage forms of glass solutions by applying a second, rate controlling membrane on top of the glass solution. Adding a second coating layer adds to the physical and chemical complexity of the drug delivery system, so a thorough understanding of the physical structure and phase behavior of the different coating layers is needed. This study aimed to investigate the surface and cross-sectional characteristics (employing scanning electron microscopy (SEM) and time of flight secondary ion mass spectrometry (ToF-SIMS)) of an indomethacin-polyvinylpyrrolidone (PVP) glass solution, top-coated with a release rate controlling membrane consisting of either ethyl cellulose or Eudragit RL. The implications of the addition of a pore former (PVP) and the coating medium (ethanol or water) were also considered. In addition, polymer miscibility and the phase analysis of the underlying glass solution were investigated. Significant differences in surface and cross-sectional topography of the different rate controlling membranes or the way they are applied (solution vs dispersion) were observed. These observations can be linked to the polymer miscibility differences. The presence of PVP was observed in all rate controlling membranes, even if it is not part of the coating solution. This could be attributed to residual powder presence in the coating chamber. The distribution of PVP among the sample surfaces depends on the concentration and the rate controlling polymer used. Differences can again be linked to polymer miscibility. Finally, it was shown that the underlying glass solution layer

  16. Pulmonary ventilation/perfusion scan

    Science.gov (United States)

    ... to stop eating (fast), be on a special diet, or take any medicines before the test. A chest x-ray is usually done before or after a ventilation and perfusion scan. You wear a hospital gown or comfortable clothing that does not have ...

  17. Improvements in the technique of spinal subarachnoid recirculatory perfusion

    International Nuclear Information System (INIS)

    Sullivan, H.G.; Allison, J.D.; Kingsbury, T.B.; Goode, J.J.; Sims, W.L.

    1984-01-01

    With 14 C-labeled dextran as the tracer, studies of the original configuration of spinal recirculatory perfusion and the original model for data analysis demonstrated that this approach does not yield acceptable accuracy in determining cerebrospinal fluid (CSF) formation (Fcsf) and absorption (Acsf) rates. A significant component of this error was due to the fact that the method of data analysis used originally is not based on a realistic mathematical model of the system. A more realistic mathematical model resulted in two simultaneous differential equations that did not have simple analytical solutions and, therefore, could not be used easily for data analysis. By computer simulation, a comparison of the more realistic model with the original model demonstrated that, under ideal conditions, there was a 10% error inherent in the original data analysis method. A new system configuration and new data analysis methods have been developed. In the new system, the syringe is removed from the external circuit and intracranial pressure is controlled by infusion from a separate reservoir where the pressure head is maintained at any desired level by feedback control. Spectrophotometry is used to measure tracer concentration in the external circuit. Data collection and analysis are fully automated under computer control so that, during an experimental run, the investigators are updated at 1- to 2-second intervals as to the convergence of the data analysis routine. All of the data during the initial period of nonhomogeneous mixing are used to calculate Fcsf and Acsf. With the new system and a simple phantom of the CSF system, the mean error in finding Acsf was 1.7 +/- 1.2% for 27 determinations covering a wide range of absorption rates. Fcsf could be determined to within 0.001 ml/minute. In up to six sequential pressure plateaus, the magnitude of error did not increase with each subsequent run

  18. Detection of reactive oxygen species in isolated, perfused lungs by electron spin resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Schudt Christian

    2005-07-01

    Full Text Available Abstract Background The sources and measurement of reactive oxygen species (ROS in intact organs are largely unresolved. This may be related to methodological problems associated with the techniques currently employed for ROS detection. Electron spin resonance (ESR with spin trapping is a specific method for ROS detection, and may address some these technical problems. Methods We have established a protocol for the measurement of intravascular ROS release from isolated buffer-perfused and ventilated rabbit and mouse lungs, combining lung perfusion with the spin probe l-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CPH and ESR spectroscopy. We then employed this technique to characterize hypoxia-dependent ROS release, with specific attention paid to NADPH oxidase-dependent superoxide formation as a possible vasoconstrictor pathway. Results While perfusing lungs with CPH over a range of inspired oxygen concentrations (1–21 %, the rate of CP• formation exhibited an oxygen-dependence, with a minimum at 2.5 % O2. Addition of superoxide dismutase (SOD to the buffer fluid illustrated that a minor proportion of this intravascular ROS leak was attributable to superoxide. Stimulation of the lungs by injection of phorbol-12-myristate-13-acetate (PMA into the pulmonary artery caused a rapid increase in CP• formation, concomitant with pulmonary vasoconstriction. Both the PMA-induced CPH oxidation and the vasoconstrictor response were largely suppressed by SOD. When the PMA challenge was performed at different oxygen concentrations, maximum superoxide liberation and pulmonary vasoconstriction occurred at 5 % O2. Using a NADPH oxidase inhibitor and NADPH-oxidase deficient mice, we illustrated that the PMA-induced superoxide release was attributable to the stimulation of NADPH oxidases. Conclusion The perfusion of isolated lungs with CPH is suitable for detection of intravascular ROS release by ESR spectroscopy. We employed this technique to

  19. Tissue distribution of enrofloxacin after intramammary or simulated systemic administration in isolated perfused sheep udders.

    Science.gov (United States)

    López Cadenas, Cristina; Fernández Martínez, Nélida; Sierra Vega, Matilde; Diez Liébana, Maria J; Gonzalo Orden, Jose M; Sahagún Prieto, Ana M; García Vieitez, Juan J

    2012-11-01

    To determine the tissue distribution of enrofloxacin after intramammary or simulated systemic administration in isolated perfused sheep udders by measuring its concentration at various sample collection sites. 26 udders (obtained following euthanasia) from 26 healthy lactating sheep. For each isolated udder, 1 mammary gland was perfused with warmed, gassed Tyrode solution. Enrofloxacin (1 g of enrofloxacin/5 g of ointment) was administered into the perfused gland via the intramammary route or systemically via the perfusion fluid (equivalent to a dose of 5 mg/kg). Samples of the perfusate were obtained every 30 minutes for 180 minutes; glandular tissue samples were obtained at 2, 4, 6, and 8 cm from the teat base after 180 minutes. The enrofloxacin content of the perfusate and tissue samples was analyzed via high-performance liquid chromatography with UV detection. After intramammary administration, maximun perfusate enrofloxacin concentration was detected at 180 minutes and, at this time, mean tissue enrofloxacin concentration was detected and mean tissue enrofloxacin concentration was 123.80, 54.48, 36.72, and 26.42 μg/g of tissue at 2, 4, 6, and 8 cm from the teat base, respectively. Following systemic administration, perfusate enrofloxacin concentration decreased with time and, at 180 minutes, tissue enrofloxacin concentrations ranged from 40.38 to 35.58 μg/g of tissue. By 180 minutes after administration via the intramammary or systemic route in isolated perfused sheep mammary glands, mean tissue concentration of enrofloxacin was greater than the minimum inhibitory concentration required to inhibit growth of 90% of many common mastitis pathogens in sheep. Use of either route of administration (or in combination) appears suitable for the treatment of acute mastitis in sheep.

  20. Contralateral thalamic hypoperfusion on brain perfusion SPECT

    International Nuclear Information System (INIS)

    Lee, Seok Mo; Bae, Sang Kyun; Yoo, Kyung Moo; Yum, Ha Yong

    2000-01-01

    Brain perfusion single photon emission computed tomography (SPECT) is useful for the localization of cerebrovascular lesion and sometimes reveals more definite lesion than radiologic imaging modality such as CT or MRI does. The purpose of this study was to evaluate the diagnostic usefulness of brain perfusion SPECT in patients with hemisensory impairment. Thirteen consecutive patients (M:F= 8:5, mean age = 48) who has hemisensory impairment were included. Brain perfusion SPECT was performed after intravenous injection of 1110 MBq of Tc-99m ECD. The images were obtained using a dual-head gamma camera with ultra-high resolution collimator. Semiquantitative analysis was performed after placing multiple ROIs on cerebral cortex, basal ganglia, thalamus and cerebellum. There were 10 patients with left hemisensory impairment and 3 patients with right-sided symptom. Only 2 patients revealed abnormal signal change in the thalamus on MRI. But brain perfusion SPECT showed decreased perfusion in the thalamus in 9 patients. Six patients among 10 patients with left hemisensory impairment revealed decreased perfusion in the contralateral thalamus on brain SPECT. The other 4 patients revealed no abnormality. Two patients among 3 patients with right hemisensory impairment also showed decreased perfusion in the contralateral thalamus on brain SPECT. One patients with right hemisensory impairment showed ipsilateral perfusion decrease. Two patients who had follow-up brain perfusion SEPCT after treatment revealed normalization of perfusion in the thalamus. Brain perfusion SPECT might be a useful tool in diagnosing patients with hemisensory impairment

  1. Placental passage of benzoic acid, caffeine, and glyphosate in an ex vivo human perfusion system

    DEFF Research Database (Denmark)

    Mose, Tina; Kjaerstad, Mia Birkhoej; Mathiesen, Line

    2008-01-01

    group of compounds. Benzoic acid, caffeine, and glyphosate were chosen as model compounds because they are small molecules with large differences in physiochemical properties. Caffeine crossed the placenta by passive diffusion. The initial transfer rate of benzoic acid was more limited in the first part...... of the perfusion compared to caffeine, but reached the same steady-state level by the end of perfusion. The transfer of glyphosate was restricted throughout perfusion, with a lower permeation rate, and only around 15% glyphosate in maternal circulation crossed to the fetal circulation during the study period....

  2. Computational fluid dynamics (CFD) analysis of airlift bioreactor: effect of draft tube configurations on hydrodynamics, cell suspension, and shear rate.

    Science.gov (United States)

    Pawar, Sanjay B

    2018-01-01

    The biomass productivity of microalgae cells mainly depends on the hydrodynamics of airlift bioreactor (ABR). Thus, the hydrodynamics of concentric tube ABR was initially studied using two-phase three-dimensional CFD simulations with the Eulerian-Lagrangian approach. The performance of ABR (17 L) was examined for different configurations of the draft tube using various drag models such as Grace, Ishii-Zuber, and Schiller-Naumann. The gas holdups in the riser and the downcomer were well predicted using E-L approach. This work was further extended to study the dispersion of microalgae cells in the ABR using three-phase CFD simulations. In this model (combined E-E and E-L), the solid phase (microalgae cells) was dispersed into the continuous liquid phase (water), while the gas phase (air bubbles) was modeled as a particle transport fluid. The effect of non-drag forces such as virtual mass and lift forces was also considered. Flow regimes were explained on the basis of the relative gas holdup distribution in the riser and the downcomer. The microalgae cells were found in suspension for the superficial gas velocities of 0.02-0.04 m s -1 experiencing an average shear of 23.52-44.56 s -1 which is far below the critical limit of cell damage.

  3. Dynamic and rate-dependent yielding behavior of Co{sub 0.9}Ni{sub 0.1} microcluster based magnetorheological fluids

    Energy Technology Data Exchange (ETDEWEB)

    Arief, Injamamul; Mukhopadhyay, P.K., E-mail: pkm@bose.res.in

    2016-01-01

    In this paper we performed steady shear and oscillatory magnetorheological (MR) studies in magnetic fluids containing CoNi sub-micron sized clusters of 450 nm in diameter. Such Co-rich nanoclusters were synthesized by conventional homogeneous nucleation without any external surfactant or reducing agent in liquid polyol at elevated temperature. The x-ray diffraction, energy dispersive x-ray analysis, scanning and transmission electron microscopy studies were done for analyzing the sample composition and morphology. Two variants of fluid samples were prepared by dispersing 15 vol% and 20 vol% of CoNi powders in castor oil. Room temperature steady magnetoshear studies indicate viscoplastic behavior with stronger dependence of static yield stress on magnetization than a dipolar coupling that was operational in the dynamic yield stress. Magnetosweep measurements at constant shear rate showed interesting viscous relaxation at high magnetic fields. We also explored dynamical elastic behavior through oscillatory magnetorheological studies under both strain sweep and frequency sweep modes, and showed glass transition like phenomenon occurring in them above critical shear amplitudes. - Highlights: • A typical polymer/surfactant free polyol reduction method was used to synthesize large-scale Co{sub 0.9}Ni{sub 0.1} nanoclusters. • Room temperature rate-dependent magnetorheology of CoNi-nanoclusters based MR fluids revealed viscoplastic behavior. • Magnetic fields were replaced by powder particle magnetization (M) for better yield stress scaling. • In addition to previously reported M{sup 2}-dependence, higher order relations (~M{sup 3}) were also noted for static yield stress. • An interesting viscous relaxation phenomenon occurred at higher magnetic fields.

  4. Reactivity of the isolated perfused rat tail vascular bed

    Directory of Open Access Journals (Sweden)

    A.S. França

    1997-07-01

    Full Text Available Isolated segments of the perfused rat tail artery display a high basal tone when compared to other isolated arteries such as the mesenteric and are suitable for the assay of vasopressor agents. However, the perfusion of this artery in the entire tail has not yet been used for functional studies. The main purpose of the present study was to identify some aspects of the vascular reactivity of the rat tail vascular bed and validate this method to measure vascular reactivity. The tail severed from the body was perfused with Krebs solution containing different Ca2+ concentrations at different flow rates. Rats were anesthetized with sodium pentobarbital (65 mg/kg and heparinized (500 U. The tail artery was dissected near the tail insertion, cannulated and perfused with Krebs solution plus 30 µM EDTA at 36oC and 2.5 ml/min and the procedures were started after equilibration of the perfusion pressure. In the first group a dose-response curve to phenylephrine (PE (0.5, 1, 2 and 5 µg, bolus injection was obtained at different flow rates (1.5, 2.5 and 3.5 ml/min. The mean perfusion pressure increased with flow as well as PE vasopressor responses. In a second group the flow was changed (1.5, 2, 2.5, 3 and 3.5 ml/min at different Ca2+ concentrations (0.62, 1.25, 2.5 and 3.75 mM in the Krebs solution. Increasing Ca2+ concentrations did not alter the flow-pressure relationship. In the third group a similar protocol was performed but the rat tail vascular bed was perfused with Krebs solution containing PE (0.1 µg/ml. There was an enhancement of the effect of PE with increasing external Ca2+ and flow. PE vasopressor responses increased after endothelial damage with air and CHAPS, suggesting an endothelial modulation of the tone of the rat tail vascular bed. These experiments validate the perfusion of the rat tail vascular bed as a method to investigate vascular reactivity

  5. Evolução de variáveis hemodinâmicas e perfusionais durante o choque séptico experimental tratado com ressuscitação volêmica guiada por metas Hemodynamic and perfusion variables during experimental septic shock treated with goal-directed fluid resuscitation

    Directory of Open Access Journals (Sweden)

    Marcelo Park

    2011-09-01

    gold standard in sepsis therapy, few studies have described hemodynamic and perfusion parameters during this procedure. This study aims to describe these parameters during septic shock without resuscitation and after 12 hours of goal-directed resuscitation. METHODS: Thirteen anesthetized pigs (35-45 kg had peritonitis caused by fecal inoculation (0.75 g/kg. After developing persistent hypotension, both groups were given antibiotics and randomized either to the control group (n=7 or the experimental group (n=6. In the control group, hemodynamic control was optimized to maintain a central venous pressure of 8-12 mmHg, a urinary output above 0.5 mL/kg/hour and a mean arterial blood pressure above 65 mmHg. The experimental group received the above target therapy in addition to maintaining a SvO2 above 65%. The interventions included lactated Ringer's solution and norepinephrine for both groups and dobutamine in the SvO2 group. The animals were treated for 12 hours or until death. RESULTS: Untreated sepsis was associated with significant reductions in SvO2, PvO2, cardiac output and central venous pressure in addition to increased arteriovenous oxygen saturation and veno-arterial CO2 differences. Following resuscitation, these parameters were corrected in both groups. Goal-directed resuscitation was associated with a better hemodynamic profile, characterized by higher SvO2, cardiac output and central venous pressure. CONCLUSIONS: Non-resuscitated sepsis showed a hemodynamic profile suggesting hypovolemia, with worsened perfusion and hemodynamics, which is reversed upon fluid resuscitation. Goal-directed resuscitation is associated with significantly improved hemodynamic and perfusion parameters

  6. Method for the assessment of placental blood perfusion using /sup 99/Tc pertechnetate

    Energy Technology Data Exchange (ETDEWEB)

    Suonio, S; Olkkonen, H [Kuopio Central Hospital (Finland)

    1977-10-01

    A radioisotope method was developed for the measurement of placental blood flow using /sup 99/Tc pertechnetate as a tracer and a single detector as a measuring device. The results are given as placental perfusion rate (ml/min/ml) calculated from the tracer-appearance curve. The series consisted of 148 healthy pregnant women between the 28th and 42nd week and fifty pregnancies with a hypertensive disease. In healthy subjects the placental perfusion rate increased by about 32% in the period between 28th and 38th week, but there was a large variation. The perfusion rate showed a tendency to diminish at term. In a group of fifty hypertensive pregnancies a highly significant decrease in the perfusion rate was observed when compared with normal subjects. The conclusion drawn is that this method can be used for the quantitative measurement of placental blood supply.

  7. Differential and directional effects of perfusion on electrical and thermal conductivities in liver.

    Science.gov (United States)

    Podhajsky, Ronald J; Yi, Ming; Mahajan, Roop L

    2009-01-01

    Two different measurement probes--an electrical probe and a thermal conductivity probe--were designed, fabricated, calibrated, and used in experimental studies on a pig liver model that was designed to control perfusion rates. These probes were fabricated by photolithography and mounted in 1.5-mm diameter catheters. We measured the local impedance and thermal conductivity, respectively, of the artificially perfused liver at different flow rates and, by rotating the probes, in different directions. The results show that both the local electrical conductivity and the thermal conductivity varied location to location, that thermal conductivity increased with decreased distance to large blood vessels, and that significant directional differences exist in both electrical and thermal conductivities. Measurements at different perfusion rates demonstrated that both the local electrical and local thermal conductivities increased linearly with the square root of perfusion rate. These correlations may be of great value to many energy-based biomedical applications.

  8. Characterizing potential heart agents with an isolated perfused heart system

    International Nuclear Information System (INIS)

    Pendleton, D.B.; Sands, H.; Gallagher, B.M.; Camin, L.L.

    1984-01-01

    The authors have used an isolated perfused heart system for characterizing potential myocardial perfusion radiopharamaceuticals. Rabbit or guinea pig (GP) hearts are removed and perfused through the aorta with a blood-free buffer. Heart rate and ventricular pressure are monitored as indices of viability. Tc-99m-MAA is 96-100% retained in these hearts, and Tc-99m human serum albumin shows less than 5% extraction. Tl-201 is 30-40% extracted. It is known that in-vivo, Tc-99m(dmpe)/sub 2/Cl/sub 2//sup +/ is taken up by rabbit heart but not by GP or human heart. Analogous results are obtained with the isolated perfused heart model, where the complex is extracted well by the isolated rabbit heart (24%) but not by the GP heart (<5%). Values are unchanged if human, rabbit or GP blood is mixed and co-injected with the complex. Tc-99m)dmpe)/sub 3//sup +/ is also taken up by rabbit but not by GP hearts in-vivo. However, isolated perfused hearts of both species extract this complex well (45-52%). Heart uptake is diminished to <7% if the complex is pre-equilibrated with human blood. GP blood produces a moderate inhibition (in GP hearts only) and rabbit blood has no effect. This suggests that a human or GP blood factor may have a significant effect on heart uptake of this complex. Tc-99m(CN-t-butyl)/sub 6//sup +/ is taken up well by both rabbit and GP hearts in-vivo, and is extracted 100% by both isolated perfused hearts. Heart retention remains high (73-75%) in the presence of human blood

  9. Effect of brine flow rate on the performance of a spiral-jacketed thermal storage tank used for SDHW systems: A computational fluid dynamics study

    International Nuclear Information System (INIS)

    Baek, Seung Man; Nam, Jin Hyun; Hong, Hiki; Kim, Charn-Jung

    2011-01-01

    This study numerically investigates the effect of the brine flow rate on the thermal performance of a spiral-jacketed thermal storage tank (TST) installed in a solar domestic hot water (SDHW) system. The spiral-jacketed TST is a TST with a mantle heat exchanger, consisting of a vertical, cylindrical water tank for energy storage and a spiral brine flow path attached to the tank wall for heat transfer. A computational fluid dynamics (CFD) model was constructed based on the actual geometry of a spiral-jacketed TST. In addition, the boundary conditions were defined by considering solar radiation and ambient temperature data that were measured during experimental operation of the SDHW system. The numerical results demonstrated that an increase in the brine flow rate enhances the thermal efficiency of the TST due to higher heat transfer coefficients in the spiral path, and also leads to reduced thermal stratification in the TST. On the other hand, a lower brine flow rate increased the heat transfer rate at the inlet of the spiral path near the top of the TST, which resulted in enhanced thermal stratification. The optimal range for the rate of brine flow rate is discussed with respect to the thermal efficiency of the TST and the required pumping power for brine circulation in the spiral flow path. - Highlights: → A CFD model was developed for a spiral-jacketed thermal storage tank (TST) installed in a solar domestic hot water (SDHW) system. → Effects of brine flow rate on the overall performance of the spiral-jacketed TST were numerically investigated. → Higher brine flow rates slightly increased the solar energy acquired by the TST, but it also increased the pump power required to circulate the brine. → Lower brine flow rates were found to be a better option for the spiral-jacketed TST, by maximizing the exergy of the SDHW system.

  10. Doppler optical coherence tomography imaging of local fluid flow and shear stress within microporous scaffolds

    Science.gov (United States)

    Jia, Yali; Bagnaninchi, Pierre O.; Yang, Ying; Haj, Alicia El; Hinds, Monica T.; Kirkpatrick, Sean J.; Wang, Ruikang K.

    2009-05-01

    Establishing a relationship between perfusion rate and fluid shear stress in a 3D cell culture environment is an ongoing and challenging task faced by tissue engineers. We explore Doppler optical coherence tomography (DOCT) as a potential imaging tool for in situ monitoring of local fluid flow profiles inside porous chitosan scaffolds. From the measured fluid flow profiles, the fluid shear stresses are evaluated. We examine the localized fluid flow and shear stress within low- and high-porosity chitosan scaffolds, which are subjected to a constant input flow rate of 0.5 ml.min-1. The DOCT results show that the behavior of the fluid flow and shear stress in micropores is strongly dependent on the micropore interconnectivity, porosity, and size of pores within the scaffold. For low-porosity and high-porosity chitosan scaffolds examined, the measured local fluid flow and shear stress varied from micropore to micropore, with a mean shear stress of 0.49+/-0.3 dyn.cm-2 and 0.38+/-0.2 dyn.cm-2, respectively. In addition, we show that the scaffold's porosity and interconnectivity can be quantified by combining analyses of the 3D structural and flow images obtained from DOCT.

  11. Dual-energy CT perfusion and angiography in chronic thromboembolic pulmonary hypertension: diagnostic accuracy and concordance with radionuclide scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Dournes, Gael; Verdier, Damien; Montaudon, Michel; Laurent, Francois; Lederlin, Mathieu [Hopital Haut-Leveque, CHU Bordeaux, Department of Medical Imaging, Pessac (France); University Bordeaux Segalen, Bordeaux Cedex (France); Bullier, Eric; Riviere, Annalisa [Hopital Haut-Leveque, CHU Bordeaux, Department of Nuclear Medicine, Pessac (France); Dromer, Claire [Hopital Haut-Leveque, CHU Bordeaux, Department of Respiratory Diseases, Pessac (France); Picard, Francois [Hopital Haut-Leveque, CHU Bordeaux, Department of Cardiology, Pessac (France); Billes, Marc-Alain [Hopital Haut-Leveque, CHU Bordeaux, Department of Cardiac Surgery, Pessac (France); Corneloup, Olivier [Hopital Haut-Leveque, CHU Bordeaux, Department of Medical Imaging, Pessac (France)

    2014-01-15

    To evaluate the diagnostic accuracy of dual-energy computed tomography (DECT) perfusion and angiography versus ventilation/perfusion (V/Q) scintigraphy in chronic thromboembolic pulmonary hypertension (CTEPH), and to assess the per-segment concordance rate of DECT and scintigraphy. Forty consecutive patients with proven pulmonary hypertension underwent V/Q scintigraphy and DECT perfusion and angiography. Each imaging technique was assessed for the location of segmental defects. Diagnosis of CTEPH was established when at least one segmental perfusion defect was detected by scintigraphy. Diagnostic accuracy of DECT perfusion and angiography was assessed and compared with scintigraphy. In CTEPH patients, the per-segment concordance between scintigraphy and DECT perfusion/angiography was calculated. Fourteen patients were diagnosed with CTEPH and 26 with other aetiologies. DECT perfusion and angiography correctly identified all CTEPH patients with sensitivity/specificity values of 1/0.92 and 1/0.93, respectively. At a segmental level, DECT perfusion showed moderate agreement (κ = 0.44) with scintigraphy. Agreement between CT angiography and scintigraphy ranged from fair (κ = 0.31) to slight (κ = 0.09) depending on whether completely or partially occlusive patterns were considered, respectively. Both DECT perfusion and angiography show satisfactory performance for the diagnosis of CTEPH. DECT perfusion is more accurate than angiography at identifying the segmental location of abnormalities. (orig.)

  12. Dual-energy CT perfusion and angiography in chronic thromboembolic pulmonary hypertension: diagnostic accuracy and concordance with radionuclide scintigraphy

    International Nuclear Information System (INIS)

    Dournes, Gael; Verdier, Damien; Montaudon, Michel; Laurent, Francois; Lederlin, Mathieu; Bullier, Eric; Riviere, Annalisa; Dromer, Claire; Picard, Francois; Billes, Marc-Alain; Corneloup, Olivier

    2014-01-01

    To evaluate the diagnostic accuracy of dual-energy computed tomography (DECT) perfusion and angiography versus ventilation/perfusion (V/Q) scintigraphy in chronic thromboembolic pulmonary hypertension (CTEPH), and to assess the per-segment concordance rate of DECT and scintigraphy. Forty consecutive patients with proven pulmonary hypertension underwent V/Q scintigraphy and DECT perfusion and angiography. Each imaging technique was assessed for the location of segmental defects. Diagnosis of CTEPH was established when at least one segmental perfusion defect was detected by scintigraphy. Diagnostic accuracy of DECT perfusion and angiography was assessed and compared with scintigraphy. In CTEPH patients, the per-segment concordance between scintigraphy and DECT perfusion/angiography was calculated. Fourteen patients were diagnosed with CTEPH and 26 with other aetiologies. DECT perfusion and angiography correctly identified all CTEPH patients with sensitivity/specificity values of 1/0.92 and 1/0.93, respectively. At a segmental level, DECT perfusion showed moderate agreement (κ = 0.44) with scintigraphy. Agreement between CT angiography and scintigraphy ranged from fair (κ = 0.31) to slight (κ = 0.09) depending on whether completely or partially occlusive patterns were considered, respectively. Both DECT perfusion and angiography show satisfactory performance for the diagnosis of CTEPH. DECT perfusion is more accurate than angiography at identifying the segmental location of abnormalities. (orig.)

  13. Influence of Cutting Fluid Flow Rate and Cutting Parameters on the Surface Roughness and Flank Wear of TiAlN Coated Tool In Turning AISI 1015 Steel Using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Moganapriya C.

    2017-09-01

    Full Text Available This paper presents the influence of cutting parameters (Depth of cut, feed rate, spindle speed and cutting fluid flow rate on the surface roughness and flank wear of physical vapor deposition (PVD Cathodic arc evaporation coated TiAlN tungsten carbide cutting tool insert during CNC turning of AISI 1015 mild steel. Analysis of Variance has been applied to determine the critical influence of cutting parameters. Taguchi orthogonal test design has been employed to optimize the process parameters affecting surface roughness and tool wear. Depth of cut was found to be the most dominant factor contributing to high surface roughness (67.5% of the inserts. However, cutting speed, feed rate and flow rate of cutting fluid showed minimal contribution to surface roughness. On the other hand, cutting speed (45.6% and flow rate of cutting fluid (23% were the dominant factors influencing tool wear. The optimum cutting conditions for desired surface roughness constitutes the following parameters such as medium cutting speed, low feed rate, low depth of cut and high cutting fluid flow rate. Minimal tool wear was achieved for the following process parameters such as low cutting speed, low feed rate, medium depth of cut and high cutting fluid flow rate.

  14. Hyperventilation, cerebral perfusion, and syncope

    DEFF Research Database (Denmark)

    Immink, R V; Pott, F C; Secher, N H

    2014-01-01

    dioxide (PaCO2) and oxygen (PaO2) partial pressures so that hypercapnia/hypoxia increases and hypocapnia/hyperoxia reduces global cerebral blood flow. Cerebral hypoperfusion and TLOC have been associated with hypocapnia related to HV. Notwithstanding pronounced cerebrovascular effects of PaCO2...... the contribution of a low PaCO2 to the early postural reduction in middle cerebral artery blood velocity is transient. HV together with postural stress does not reduce cerebral perfusion to such an extent that TLOC develops. However when HV is combined with cardiovascular stressors like cold immersion or reduced...... cardiac output brain perfusion becomes jeopardized. Whether, in patients with cardiovascular disease and/or defect, cerebral blood flow cerebral control HV-induced hypocapnia elicits cerebral hypoperfusion, leading to TLOC, remains to be established....

  15. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...... turbo-FLASH (fast low-angle shot) sequence and Gd-DTPA has been presented. Here, an extension of the model is presented taking into account fast and slow water exchange between the compartments, enabling the calculation of the unidirectional influx constant (Ki) for Gd-DTPA, the distribution volume...... of Gd-DTPA (lambda), the vascular blood volume (Vb), and the time delay through the coronary arteries (delta T). The model was evaluated by computer simulation and used on experimental results from seven healthy subjects. The results in the healthy volunteers for a region of interest placed...

  16. Dosimetry in myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, Janine M.; Trindade, Bruno; Ribeiro, Tarcisio P.C. [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2011-07-01

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  17. Dosimetry in myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Toledo, Janine M.; Trindade, Bruno; Ribeiro, Tarcisio P.C.

    2011-01-01

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  18. Preservation of the Myofascial Cuff During Posterior Fossa Surgery to Reduce the Rate of Pseudomeningocele Formation and Cerebrospinal Fluid Leak: A Technical Note.

    Science.gov (United States)

    Felbaum, Daniel R; Mueller, Kyle; Anaizi, Amjad; Mason, Robert B; Jean, Walter C; Voyadzis, Jean M

    2016-12-28

     Suboccipital craniotomy is a workhorse neurosurgical operation for approaching the posterior fossa but carries a high risk of pseudomeningocele and cerebrospinal fluid (CSF) leak. We describe our experience with a simple T-shaped fascial opening that preserves the occipital myofascial cuff as compared to traditional methods to reduce this risk.  A single institution, retrospective review of prospectively collected database was performed of patients that underwent a suboccipital craniectomy or craniotomy. Patient data was reviewed for craniotomy or craniectomy, dural graft, and/or sealant use as well as CSF complications. A pseudomeningocele was defined as a subcutaneous collection of cerebrospinal fluid palpable clinically and confirmed on imaging. A CSF leak was defined as a CSF-cutaneous fistula manifested by CSF leaking through the wound. All patients underwent regular postoperative visits of two weeks, one month, and three months.  Our retrospective review identified 33 patients matching the inclusion criteria. Overall, our cohort had a 21% (7/33) rate of clinical and radiographic pseudomeningocele formation with 9% (3/33) requiring surgical revision or a separate procedure. The rate of clinical and radiographic pseudomeningocele formation in the myofascial cuff preservation technique was less than standard techniques (12% and 31%, respectively). Revision or further surgical procedures were also reduced in the myofascial cuff preservation technique vs. the standard technique (6% vs 13%).  Preservation of the myofascial cuff during posterior fossa surgery is a simple and adoptable technique that reduces the rate of pseudomeningocele formation and CSF leak as compared with standard techniques.

  19. Perfusion abnormalities in congenital and neoplastic pulmonary disease: comparison of MR perfusion and multislice CT imaging

    International Nuclear Information System (INIS)

    Boll, Daniel T.; Lewin, Jonathan S.; Young, Philip; Gilkeson, Robert C.; Siwik, Ernest S.

    2005-01-01

    The aim of this work was to assess magnetic resonance (MR) perfusion patterns of chronic, nonembolic pulmonary diseases of congenital and neoplastic origin and to compare the findings with results obtained with pulmonary, contrast-enhanced multislice computed tomography (CT) imaging to prove that congenital and neoplastic pulmonary conditions require MR imaging over the pulmonary perfusion cycle to successfully and directly detect changes in lung perfusion patterns. Twenty-five patients underwent concurrent CT and MR evaluation of chronic pulmonary diseases of congenital (n=15) or neoplastic (n=10) origin. Analysis of MR perfusion and contrast-enhanced CT datasets was realized by defining pulmonary and vascular regions of interest in corresponding positions. MR perfusion calculated time-to-peak enhancement, maximal enhancement and the area under the perfusion curve. CT datasets provided pulmonary signal-to-noise ratio measurements. Vessel centerlines of bronchial arteries were determined. Underlying perfusion type, such as pulmonary arterial or systemic arterial supply, as well as regions with significant variations in perfusion were determined statistically. Analysis of the pulmonary perfusion pattern detected pulmonary arterial supply in 19 patients; six patients showed systemic arterial supply. In pulmonary arterial perfusion, MR and multislice CT imaging consistently detected the perfusion type and regions with altered perfusion patterns. In bronchial arterial supply, MR perfusion and CT imaging showed significant perfusion differences. Patients with bronchial arterial supply had bronchial arteries ranging from 2.0 to 3.6 mm compared with submillimeter diameters in pulmonary arterial perfusion. Dynamic MR imaging of congenital and neoplastic pulmonary conditions allowed characterization of the pulmonary perfusion type. CT imaging suggested the presence of systemic arterial perfusion by visualizing hypertrophied bronchial arteries. (orig.)

  20. Perfusion of tumor-bearing kidneys as a model for scintigraphic screening of monoclonal antibodies

    International Nuclear Information System (INIS)

    van Dijk, J.; Oosterwijk, E.; van Kroonenburgh, M.J.; Jonas, U.; Fleuren, G.J.; Pauwels, E.K.; Warnaar, S.O.

    1988-01-01

    Tumor-bearing human kidneys were used in an ex vivo perfusion model to screen monoclonal antibodies, recognizing renal cell carcinoma-associated antigens for diagnostic potential in vivo. Perfusion of tumor-bearing kidneys with /sup 99m/Tc-labeled G250 and RC38 antibody resulted in visualization of the tumor, whereas perfusion with two other monoclonal antibodies, RC2 and RC4, did not lead to tumor visualization. Uptake of radiolabel in normal kidney tissue was low for G250 and RC38 antibody. Tumor-to-kidney tissue ratios after perfusion with G250 and RC38 antibody were 2.7 and 2.2, respectively. After rinsing for 3 hr with unlabeled perfusion fluid the tumor-to-kidney tissue ratios increased to 8.6 for G250 antibody and to 2.7 for RC38 antibody. We conclude that perfusion of tumor-bearing human kidneys with radiolabeled monoclonal antibodies is a relatively simple way to evaluate renal cell carcinoma associated monoclonal antibodies as diagnostic agents in vivo

  1. Brain perfusion SPECT correlates with CSF biomarkers in Alzheimer's disease

    Energy Technology Data Exchange (ETDEWEB)

    Habert, Marie-Odile [UMR-S 678, Universite Pierre et Marie Curie-Paris 6, INSERM, Paris (France); CHU Pitie-Salpetriere, AP-HP, Department of Nuclear Medicine, Paris (France); Hopital Pitie-Salpetriere, Department of Nuclear Medicine, Paris (France); Souza, Leonardo Cruz de; Dubois, Bruno; Sarazin, Marie [CHU Pitie-Salpetriere, AP-HP, Research and Resource Memory Centre and INSERM U610, Paris (France); Lamari, Foudil; Jardel, Claude [CHU Pitie-Salpetriere, AP-HP, Department of Metabolic Biochemistry, Paris (France); Daragon, Nelle; Desarnaud, Serge [CHU Pitie-Salpetriere, AP-HP, Department of Nuclear Medicine, Paris (France)

    2010-03-15

    Our aim was to study the correlations between cerebrospinal fluid (CSF) biomarker levels such as {beta}-amyloid 42 (A{beta}{sub 42}), total and phosphorylated tau protein (T-tau and P-tau) and brain perfusion SPECT in Alzheimer's disease (AD) using a voxel-based methodology. Patients (n = 31) with clinical features of AD (n = 25) or amnestic mild cognitive impairment (aMCI) (n = 6) were retrospectively included. All subjects underwent the same clinical, neuropsychological and neuroimaging tests. They had a lumbar puncture and a brain perfusion ({sup 99m}Tc-ECD) SPECT within a time interval of 10 ({+-}26) days. Correlations between CSF biomarker concentrations and perfusion were studied using SPM2 software. Individual normalised regional activity values were extracted from the eligible clusters for calculation of correlation coefficients. No significant correlation was found between A{beta}{sub 42} concentrations and brain perfusion. A significant correlation (p < 0.01, corrected) was found between T-tau or P-tau concentrations and perfusion in the left parietal cortex. Our results suggest a strong correlation between T-tau and P-tau levels and decreased brain perfusion in regions typically affected by neuropathological changes in AD. (orig.)

  2. Predicting permeability of regular tissue engineering scaffolds: scaling analysis of pore architecture, scaffold length, and fluid flow rate effects.

    Science.gov (United States)

    Rahbari, A; Montazerian, H; Davoodi, E; Homayoonfar, S

    2017-02-01

    The main aim of this research is to numerically obtain the permeability coefficient in the cylindrical scaffolds. For this purpose, a mathematical analysis was performed to derive an equation for desired porosity in terms of morphological parameters. Then, the considered cylindrical geometries were modeled and the permeability coefficient was calculated according to the velocity and pressure drop values based on the Darcy's law. In order to validate the accuracy of the present numerical solution, the obtained permeability coefficient was compared with the published experimental data. It was observed that this model can predict permeability with the utmost accuracy. Then, the effect of geometrical parameters including porosity, scaffold pore structure, unit cell size, and length of the scaffolds as well as entrance mass flow rate on the permeability of porous structures was studied. Furthermore, a parametric study with scaling laws analysis of sample length and mass flow rate effects on the permeability showed good fit to the obtained data. It can be concluded that the sensitivity of permeability is more noticeable at higher porosities. The present approach can be used to characterize and optimize the scaffold microstructure due to the necessity of cell growth and transferring considerations.

  3. In situ monitoring of localized shear stress and fluid flow within developing tissue constructs by Doppler optical coherence tomography

    Science.gov (United States)

    Jia, Yali; Bagnaninchi, Pierre O.; Wang, Ruikang K.

    2008-02-01

    Mechanical stimuli can be introduced to three dimensional (3D) cell cultures by use of perfusion bioreactor. Especially in musculoskeletal tissues, shear stress caused by fluid flow generally increase extra-cellular matrix (ECM) production and cell proliferation. The relationship between the shear stress and the tissue development in situ is complicated because of the non-uniform pore distribution within the cell-seeded scaffold. In this study, we firstly demonstrated that Doppler optical coherence tomography (DOCT) is capable of monitoring localized fluid flow and shear stress in the complex porous scaffold by examining their variation trends at perfusion rate of 5, 8, 10 and 12 ml/hr. Then, we developed the 3D porous cellular constructs, cell-seeded chitosan scaffolds monitored during several days by DOCT. The fiber based fourier domain DOCT employed a 1300 nm superluminescent diode with a bandwidth of 52 nm and a xyz resolution of 20×20×15 μm in free space. This setup allowed us not only to assess the cell growth and ECM deposition by observing their different scattering behaviors but also to further investigate how the cell attachment and ECM production has the effect on the flow shear stress and the relationship between flow rate and shear stress in the developing tissue construct. The possibility to monitor continuously the constructs under perfusion will easily indicate the effect of flow rate or shear stress on the cell viability and cell proliferation, and then discriminate the perfusion parameters affecting the pre-tissue formation rate growth.

  4. Transplacental pharmacokinetics of diclofenac in perfused human placenta.

    Science.gov (United States)

    Shintaku, Kyohei; Hori, Satoko; Tsujimoto, Masayuki; Nagata, Hideaki; Satoh, Shoji; Tsukimori, Kiyomi; Nakano, Hitoo; Fujii, Tomoyuki; Taketani, Yuji; Ohtani, Hisakazu; Sawada, Yasufumi

    2009-05-01

    The aims of this study were to evaluate the transplacental transfer properties of diclofenac and to determine the effect of L-lactic acid on the transplacental transfer of diclofenac. The maternal and fetal vessels of human placenta were perfused in a single-pass mode with a solution containing diclofenac and antipyrine. The transplacental pharmacokinetic model was fitted to the time profiles of the drug concentrations in the effluent and placenta to obtain transplacental pharmacokinetic parameters. In addition, chloride ion in the perfusate was partially replaced with L-lactic acid to see the change in the transplacental transfer properties of diclofenac. The TPT(ss) value (ratio of the rate of amount transferred across the placenta to that infused in the steady state) of diclofenac was 2.22%, which was approximately one-third that of antipyrine and was significantly reduced in the presence of L-lactic acid. The transplacental pharmacokinetic model could adequately explain the transplacental transfer of diclofenac with influx clearances from maternal and fetal perfusates to placental tissue of 0.276 and 0.0345 ml/min/g cotyledon and efflux rate constants from placental tissue to maternal and fetal perfusates of 0.406 and 0.0337 min(-1), respectively. By taking into account protein binding, the placental tissue/plasma concentration ratio in humans for diclofenac was estimated to be 0.108 ml/g of cotyledon and was smaller than that of antipyrine. In conclusion, human placental perfusion and transplacental pharmacokinetic modeling allowed us to determine the transplacental transfer properties of diclofenac quantitatively. Diclofenac may share transplacental transfer system(s) with L-lactic acid.

  5. Scaling of cerebral blood perfusion in primates and marsupials.

    Science.gov (United States)

    Seymour, Roger S; Angove, Sophie E; Snelling, Edward P; Cassey, Phillip

    2015-08-01

    The evolution of primates involved increasing body size, brain size and presumably cognitive ability. Cognition is related to neural activity, metabolic rate and rate of blood flow to the cerebral cortex. These parameters are difficult to quantify in living animals. This study shows that it is possible to determine the rate of cortical brain perfusion from the size of the internal carotid artery foramina in skulls of certain mammals, including haplorrhine primates and diprotodont marsupials. We quantify combined blood flow rate in both internal carotid arteries as a proxy of brain metabolism in 34 species of haplorrhine primates (0.116-145 kg body mass) and compare it to the same analysis for 19 species of diprotodont marsupials (0.014-46 kg). Brain volume is related to body mass by essentially the same exponent of 0.70 in both groups. Flow rate increases with haplorrhine brain volume to the 0.95 power, which is significantly higher than the exponent (0.75) expected for most organs according to 'Kleiber's Law'. By comparison, the exponent is 0.73 in marsupials. Thus, the brain perfusion rate increases with body size and brain size much faster in primates than in marsupials. The trajectory of cerebral perfusion in primates is set by the phylogenetically older groups (New and Old World monkeys, lesser apes) and the phylogenetically younger groups (great apes, including humans) fall near the line, with the highest perfusion. This may be associated with disproportionate increases in cortical surface area and mental capacity in the highly social, larger primates. © 2015. Published by The Company of Biologists Ltd.

  6. Disposition kinetics of diclofenac in the dual perfused rat liver.

    Science.gov (United States)

    Sahin, Selma; Rowland, Malcolm

    2013-09-01

    This study investigates the hepatic disposition of diclofenac as a function of route of input: portal vein (PV) versus hepatic artery (HA) in the presence of its binding protein, albumin. The in situ dual perfused rat liver was performed using Krebs bicarbonate buffer containing human serum albumin (HSA, 0.25%-1%) at constant PV (12 mL/min) and HA (3 mL/min) flow rates. Bolus doses of [(14) C]-diclofenac and (125) I-labeled HSA were injected randomly into the HA or PV and then, after an appropriate interval, into the alternate vessel. Regardless of route of input and perfusion medium protein concentration, the hepatic outflow profile of diclofenac displayed a characteristic sharp peak followed by a slower eluting tail, indicating that its radial distribution is not instantaneous. Based on the estimated effective permeability-surface area product/blood flow ratio, hepatic uptake of diclofenac is governed by both perfusion and permeability. Fractional effluent recovery (F) increased as unbound diclofenac fraction in the perfusate decreased. Although no significant difference in hepatic clearance of diclofenac as a function of route of delivery at 0.5% and 1% HSA, it was demonstrable at 0.25% HSA (p < 0.001), when the extraction ratio is higher. Copyright © 2013 Wiley Periodicals, Inc.

  7. [Portal perfusion with right gastroepiploic vein flow in liver transplant].

    Science.gov (United States)

    Mendoza-Sánchez, Federico; Javier-Haro, Francisco; Mendoza-Medina, Diego Federico; González-Ojeda, Alejandro; Cortés-Lares, José Antonio; Fuentes-Orozco, Clotilde

    Liver transplantation in patients with liver cirrhosis, portal vein thrombosis, and cavernous transformation of the portal vein, is a complex procedure with high possibility of liver graft dysfunction. It is performed in 2-19% of all liver transplants, and has a significantly high mortality rate in the post-operative period. Other procedures to maintain portal perfusion have been described, however there are no reports of liver graft perfusion using right gastroepiploic vein. A 20 year-old female diagnosed with cryptogenic cirrhosis, with a Child-Pugh score of 7 points (class "B"), and MELD score of 14 points, with thrombosis and cavernous transformation of the portal vein, severe portal hypertension, splenomegaly, a history of upper gastrointestinal bleeding due to oesophageal varices, and left renal agenesis. The preoperative evaluation for liver transplantation was completed, and the right gastroepiploic vein of 1-cm diameter was observed draining to the infrahepatic inferior vena cava and right suprarenal vein. An orthotopic liver transplantation was performed from a non-living donor (deceased on January 30, 2005) using the Piggy-Back technique. Portal vein perfusion was maintained using the right gastroepiploic vein, and the outcome was satisfactory. The patient was discharged 13 days after surgery. Liver transplantation was performed satisfactorily, obtaining an acceptable outcome. In this case, the portal perfusion had adequate blood flow through the right gastroepiploic vein. Copyright © 2015 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  8. Pulmonary artery perfusion versus no pulmonary perfusion during cardiopulmonary bypass in patients with COPD

    DEFF Research Database (Denmark)

    Buggeskov, Katrine B; Sundskard, Martin M; Jonassen, Thomas

    2016-01-01

    INTRODUCTION: Absence of pulmonary perfusion during cardiopulmonary bypass (CPB) may be associated with reduced postoperative oxygenation. Effects of active pulmonary artery perfusion were explored in patients with chronic obstructive pulmonary disease (COPD) undergoing cardiac surgery. METHODS: 90...... perfusion with normothermic oxygenated blood during cardiopulmonary bypass appears to improve postoperative oxygenation in patients with COPD undergoing cardiac surgery. Pulmonary artery perfusion with hypothermic HTK solution does not seem to improve postoperative oxygenation. TRIAL REGISTRATION NUMBER...

  9. Analysis of transient and hysteresis behavior of cross-flow heat exchangers under variable fluid mass flow rate for data center cooling applications

    International Nuclear Information System (INIS)

    Gao, Tianyi; Murray, Bruce; Sammakia, Bahgat

    2015-01-01

    Effective thermal management of data centers is an important aspect of reducing the energy required for the reliable operation of data processing and communications equipment. Liquid and hybrid (air/liquid) cooling approaches are becoming more widely used in today's large and complex data center facilities. Examples of these approaches include rear door heat exchangers, in-row and overhead coolers and direct liquid cooled servers. Heat exchangers are primary components of liquid and hybrid cooling systems, and the effectiveness of a heat exchanger strongly influences the thermal performance of a cooling system. Characterizing and modeling the dynamic behavior of heat exchangers is important for the design of cooling systems, especially for control strategies to improve energy efficiency. In this study, a dynamic thermal model is solved numerically in order to predict the transient response of an unmixed–unmixed crossflow heat exchanger, of the type that is widely used in data center cooling equipment. The transient response to step and ramp changes in the mass flow rate of both the hot and cold fluid is investigated. Five model parameters are varied over specific ranges to characterize the transient performance. The parameter range investigated is based on available heat exchanger data. The thermal response to the magnitude, time period and initial and final conditions of the transient input functions is studied in detail. Also, the hysteresis associated with the fluid mass flow rate variation is investigated. The modeling results and performance data are used to analyze specific dynamic performance of heat exchangers used in practical data center cooling applications. - Highlights: • The transient performance of a crossflow heat exchanger was modeled and studied. • This study provides design information for data center thermal management. • The time constant metric was used to study the impacts of many variable inputs. • The hysteresis behavior

  10. Normal anatomy of lung perfusion SPECT scintigraphy

    International Nuclear Information System (INIS)

    Moskowitz, G.W.; Levy, L.M.

    1987-01-01

    Ten patients studies for possible pulmonary embolic disease had normal lung perfusion planar and SPECT scintigraphy. A computer program was developed to superimpose the CT scans on corresponding SPECT images. Superimposition of CT scans on corresponding SPECT transaxial cross-sectional images, when available, provides the needed definition and relationships of adjacent organs. SPECT transaxial sections provide clear anatomic definition of perfusion defects without foreground and background lung tissue superimposed. The location, shape, and size of the perfusion defects can be readily assessed by SPECT. An algorithm was developed for the differentiation of abnormal pulmonary perfusion patterns from normal structures on variation

  11. Fluid Redistribution and Heart Rate in Humans During Whole-Body Tilting, G(z) Centrifugation, and Lower Body Negative Pressure

    Science.gov (United States)

    Watenpaugh, D. E.; Breit, G. A.; Ballard, R. E.; Murthy, G.; Hargens, A. R.

    1994-01-01

    Gravity creates blood pressure gradients which redistribute body fluids towards the feet. Positive G(z) centrifugation and lower body negative pressure (LBNP) have been proposed to simulate these and other effects of gravity during long-term existence in microgravity. We hypothesized that the magnitude of upper-to-lower body fluid redistribution would increase according to the following order: short-arm centrifugation (SAC), long-arm centrifugation (LAC), head-up tilt (HUT), and LBNP. To test this hypothesis, we employed strain gauge plethysmography of the neck, thigh and calf during HUT and supine SAC and LAC up to lG(z) at the feet, and during supine LBNP to 100 mm Hg. Supine 100 mm Hg LBNP generates footward force and produces transmural blood pressures in the foot approximately equal to 1 G(z) (90 deg) HUT. Heart rate was measured via cardiotachometry. Control measurements were made while supine. SAC and LAC elicited similar increases in thigh volume at 1 G(z) (2.3 +/- 0.4 and 2.1 +/- 0.1%, respectively; mean +/- se, n greater than or equal to 7). At 100 mm Hg LBNP, thigh volume increased (3.4 +/- 0.3%) significantly more than during l G(z) centrifugation (p less than 0.05). Surprisingly, due to a paradoxical 0.6% reduction of thigh volume between 0.8 and 1.0 G(z) HUT, thigh volume was increased only 0.6 +/- 0.3% at 1 G(z) HUT. The calf demonstrated similar, although less definitive, responses to the various gravitational stimuli. Neck volume tended to decrease less during HUT than during the other stimuli. Heart rate increased similarly during HUT (18 +/- 2 beats/min) and LAC (12 +/- 2 beats/min), and exhibited still greater elevation during LBNP (29 +/- 4 beats/min), yet did not increase during SAC. These results suggest upright posture activates mechanisms that counteract footward fluid redistribution which are not activated during supine applications of simulated gravity. LAC more closely approximated effects of normal gravity (HUT) than LBNP. Therefore

  12. Study of therapeutic and histopathologic effects of corn silk\\'s aqueous and metanolic extract against dosage induced by MDMA in isolated rat liver perfusion system

    Directory of Open Access Journals (Sweden)

    Mohammad Karami

    2014-04-01

    Full Text Available Background: Corn silk is obtained from the plant Zea mays L. A traditional herbal medicine is in China. This has been used in many parts of the world to treat edema, kidney infections, gout, kidney stones, kidney diseases and prostate. Reports of the antioxidant effects of this material are available. Although little scientific resources are available to confirm its efficacy. In this study we tried to find out the antioxidant effect and preventing of hepatotoxicity effect of Corn silk with IRLP Isolated Rat Liver Perfusion system. Material and Methods: The aqueous and methanol extracts of dried Corn silk doses (10, 20, 40, 50 and 100 mg/kg was used. Albino Rats weighing 220-180 g were examined after anesthesia by diethyl ether, the abdominal cavity of the animal T-shaped pattern excision in the abdomen and around is opened.Then portal vein connected to the perfusion flow by using small scalp Vienna (No. 23 into the portal vein. After reaching perfusion flow rate to 20 ml per minute, extracts and fraction with above doses were added to perfusion buffer. Fluid outflows from the inferior vena cava, were collected for measurement of glutathione. One sample of the liver was removed for glutathione measurement and one sample was maintained in 10% formalin for histopathological examination. Differences between group means were estimated using oneway ANOVA followed by Duncan’s multiple range test. Results: The results showed that reduced glutathione level increased significantly by aqueous and methanol extract in comparison with controls. Pathology results confirmed that by increasing dose of extracts, severity of tissue damage (hemorrhage, fibrosis, and necrosis is reduced. In samples taken at intervals of 120 minutes, changes in the glutathione of case groups showed significant difference in comparison with the control group (p<0.01. Conclusion: Findings indicated that aqueous and methanolic extracts of corn fiber, reduced hepatic damages of MDMA

  13. Using a pulse oximeter to determine clinical depth of anesthesia-investigation of the utility of the perfusion index.

    Science.gov (United States)

    Krishnamohan, Anirudh; Siriwardana, Viraj; Skowno, Justin J

    2016-11-01

    Peripheral vasodilation is a well-recognized side effect of general anesthesia, and induces changes in the amplitude of the pulse plethysmograph (PPG) waveform. This can be continuously quantitaed using the Perfusion Index (PI), a ratio of the pulsatile to nonpulsatile signal amplitude in the PPG waveform. We hypothesized that the perfusion index would rise with the induction of anesthesia in children, and fall with emergence, and performed a prospective, observational study to test this. Our primary aim was to test whether the different clinical stages of anesthesia were associated with changes in the perfusion index, and the secondary aim was to test the correlation between the normalized perfusion index and the MAC value. Twenty-one patients between the ages of 1 and 18 undergoing minor procedures with no anticipated painful stimuli were recruited. Patients with significant illnesses were excluded. Data collection commenced with a preinduction baseline, and data were collected continuously, with event marking, until completion of the anesthesia and removal of the pulse oximeter. Data collected included perfusion index, heart rate, and anesthetic gas concentration values. A normalized perfusion index was calculated by subtracting the initial baseline perfusion index value from all perfusion index values, allowing changes, from a standardized initial baseline value of zero, to be analyzed. During induction, the mean normalized perfusion index rose from 0.0 to 4.2, and then declined to 0.470 when the patients returned to consciousness. P < 0.001 using repeated measures anova test. The normalized perfusion index was correlated with MAC values (r 2 = 0.33, 95% CI 0.18-0.47, P < 0.01). The perfusion index changed significantly during different stages of anesthesia. There is a significant correlation between the perfusion index, measured by pulse oximetry, and the MAC value, in pediatric patients undergoing minor procedures. © 2016 John Wiley & Sons Ltd.

  14. Impact of CT perfusion imaging on the assessment of peripheral chronic pulmonary thromboembolism: clinical experience in 62 patients.

    Science.gov (United States)

    Le Faivre, Julien; Duhamel, Alain; Khung, Suonita; Faivre, Jean-Baptiste; Lamblin, Nicolas; Remy, Jacques; Remy-Jardin, Martine

    2016-11-01

    To evaluate the impact of CT perfusion imaging on the detection of peripheral chronic pulmonary embolisms (CPE). 62 patients underwent a dual-energy chest CT angiographic examination with (a) reconstruction of diagnostic and perfusion images; (b) enabling depiction of vascular features of peripheral CPE on diagnostic images and perfusion defects (20 segments/patient; total: 1240 segments examined). The interpretation of diagnostic images was of two types: (a) standard (i.e., based on cross-sectional images alone) or (b) detailed (i.e., based on cross-sectional images and MIPs). The segment-based analysis showed (a) 1179 segments analyzable on both imaging modalities and 61 segments rated as nonanalyzable on perfusion images; (b) the percentage of diseased segments was increased by 7.2 % when perfusion imaging was compared to the detailed reading of diagnostic images, and by 26.6 % when compared to the standard reading of images. At a patient level, the extent of peripheral CPE was higher on perfusion imaging, with a greater impact when compared to the standard reading of diagnostic images (number of patients with a greater number of diseased segments: n = 45; 72.6 % of the study population). Perfusion imaging allows recognition of a greater extent of peripheral CPE compared to diagnostic imaging. • Dual-energy computed tomography generates standard diagnostic imaging and lung perfusion analysis. • Depiction of CPE on central arteries relies on standard diagnostic imaging. • Detection of peripheral CPE is improved by perfusion imaging.

  15. Correlation of the perfusion scintigram with pulmonary functions in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Kou; Ashitaka, Tsuyoshi; Uchibori, Shigeyasu [Toho Univ., Tokyo (Japan). School of Medicine; Takano, Masaaki

    1992-11-01

    The authors carried out ventilation-perfusion scintigraphy and pulmonary function tests in 21 patients with chronic obstructive pulmonary disease. It was used [sup 99m]Tc-macroaggregate for perfusion scintigram and [sup 133]Xe gas for ventilation scintigram. It was added the radioactivities of rebreathing phase and made lung volume image using a computer. Regions of interest (ROIs) were derived from radioactivities in each image. ROIs on lung volume image included each whole lung and those on perfusion image included the areas which had relatively high radioactivity. The authors counted the area of ROIs on lung volume (L) and perfusion (P) images. Then it was used the ratio of perfusion to lung volume (P/L) as a parameter of pulmonary perfusion. P/L had the significant correlations with the vital capacity, the actual FFV[sub 1.0], arterial oxygen partial pressure, diffusing capacity, RV/TLC and peak flow rate. These results suggested that P/L was a useful parameter of pulmonary perfusion in chronic obstructive pulmonary disease. (author).

  16. Aid in the detection of myocardial perfusion abnormality utilizing SPECT atlas and images registration: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Padua, Rodrigo Donizete Santana de [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Div. de Cardiologia]. E-mail: rodrigo_dsp@hcrp.fmrp.usp.br; Oliveira, Lucas Ferrari de [Universidade Federal de Pelotas (UFPel), RS (Brazil). Inst. de Fisica e Matematica. Dept. de Tecnologia da Informacao; Marques, Paulo Mazzoncini de Azevedo [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Centro de Ciencias das Imagens e Fisica Medica; Groote, Jean-Jacques Georges Soares de [Instituto de Ensino Superior COC, Ribeirao Preto, SP (Brazil). Lab. of Artifical Intelligence and Applications; Castro, Adelson Antonio de [Universidade de Sao Paulo (USP), Ribeirao Preto, SP, (Brazil). Faculdade de Medicina; Ana, Lauro Wichert [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Centro de Ciencias das Imagens e Fisica Medica; Simoes, Marcus Vinicius [Universidade de Sao Paulo (USP), Ribeirao Preto, SP, (Brazil). Faculdade de Medicina. Divisao de Cardiologia

    2008-11-15

    To develop an atlas of myocardial perfusion scintigraphy and evaluating its applicability in computer-aided detection of myocardial perfusion defects in patients with ischemic heart disease. The atlas was created with rest-stress myocardial perfusion scintigraphic images of 20 patients of both genders with low probability of coronary artery disease and considered as normal by two experienced observers. Techniques of image registration and mathematical operations on images were utilized for obtaining template images depicting mean myocardial uptake and standard deviation for each gender and physiological condition. Myocardial perfusion scintigraphy images of one male and one female patient were aligned with the corresponding atlas template image, and voxels with myocardial uptake rates two standard deviations below the mean voxel value of the respective region in the atlas template image were highlighted on the tomographic sections and confirmed as perfusion defects by both observe. The present study demonstrated the creation of an atlas of myocardial perfusion scintigraphy with promising results of this tool as an aid in the detection of myocardial perfusion defects. However, further prospective validation with a more representative sample is recommended. (author)

  17. Reversible defects on myocardial perfusion imaging early after coronary stent implantation: a predictor of late restenosis

    International Nuclear Information System (INIS)

    Kim, D. E.; Park, S. A.; Kim, C. K.; Chang, J. A.; Jeong, J. W.; Oh, S. G.; Lee, C.

    2007-01-01

    It appears logical that myocardial perfusion should be fixed and not reversible, in the territory supplied by a dilated coronary artery. However, several studies have demonstrated reversible perfusion in the territory supplied by a coronary artery with an optimally implanted stent. The main objective of this study was to evaluate the incidence of reversible defects detected by M-SPECT early after optimal PTCA with stent implantation. Its second objective was to determine the predictive value of detecting reversible defects after stent implantation for late restenosis. Sixty-six patients that underwent M-SPECT within 24 hours of successful PTCA with stent implantation were included. All patients were followed up clinically and angiographically. The incidence of reversible perfusion defects on M-SPECT and the rate of late restenosis in target coronary arteries were evaluated retrospectively. Reversible perfusion defects on M-SPECT were observed in 26% of the patients and in 36% of lesions following successful PTCA with stent implantation. The incidence of late restenosis was significantly higher in patients and lesions with reversible perfusion defects (47% vs. 18%). According to binary logistic regression analysis, the presence of a reversible perfusion defects was the only independent predictor of late restenosis. This study shows that the predictive value of reversible perfusion defects on M-SPECT early after stent implantation with respect to the incidence of late restenosis was 47% in patients with a reversible defect, and 18% in those without it

  18. Aid in the detection of myocardial perfusion abnormality utilizing SPECT atlas and images registration: preliminary results

    International Nuclear Information System (INIS)

    Padua, Rodrigo Donizete Santana de; Oliveira, Lucas Ferrari de; Marques, Paulo Mazzoncini de Azevedo; Groote, Jean-Jacques Georges Soares de; Castro, Adelson Antonio de; Ana, Lauro Wichert; Simoes, Marcus Vinicius

    2008-01-01

    To develop an atlas of myocardial perfusion scintigraphy and evaluating its applicability in computer-aided detection of myocardial perfusion defects in patients with ischemic heart disease. The atlas was created with rest-stress myocardial perfusion scintigraphic images of 20 patients of both genders with low probability of coronary artery disease and considered as normal by two experienced observers. Techniques of image registration and mathematical operations on images were utilized for obtaining template images depicting mean myocardial uptake and standard deviation for each gender and physiological condition. Myocardial perfusion scintigraphy images of one male and one female patient were aligned with the corresponding atlas template image, and voxels with myocardial uptake rates two standard deviations below the mean voxel value of the respective region in the atlas template image were highlighted on the tomographic sections and confirmed as perfusion defects by both observe. The present study demonstrated the creation of an atlas of myocardial perfusion scintigraphy with promising results of this tool as an aid in the detection of myocardial perfusion defects. However, further prospective validation with a more representative sample is recommended. (author)

  19. Operation characteristic of a R123-based organic Rankine cycle depending on working fluid mass flow rates and heat source temperatures

    International Nuclear Information System (INIS)

    Feng, Yong-Qiang; Hung, Tzu-Chen; Wu, Shang-Lun; Lin, Chih-Hung; Li, Bing-Xi; Huang, Kuo-Chen; Qin, Jiang

    2017-01-01

    Highlights: • The operation characteristic of an Organic Rankine Cycle using R123 and a scroll expander have been investigated. • The behaviors and detailed discussion for those four major components are examined. • The expander isentropic efficiency presents a slight decrease first and then a sharp increase with mass flow rate. • The maximum electrical power and system generation efficiency are 2.01 kW and 3.25%, respectively. - Abstract: The test and operation characteristic of an organic Rankine cycle using R123 and a scroll expander have been investigated. The steady-state operation characteristic is addressed with the varying working fluid mass flow rates ranging of 0.124–0.222 kg/s and heat source temperatures ranging of 383.15–413.15 K. The behaviors and detailed discussion for those four major components (pump, evaporator, expander and condenser) are examined. The experimental results show that the environmental temperature presents a higher influence on the pump behaviors. The range of pump power consumption, isentropic efficiency and back work ratio are 0.21–0.32 kW, 26.76–53.96%, and 14–32%, respectively. The expander isentropic efficiency presents a slight decrease first and then a sharp increase with mass flow rate, while a degree of superheating more than 3 K is necessary to avoid expander cavitation. The expander isentropic and generator efficiencies are in range of 69.10–85.17% and 60–73%, respectively, while the respective heat transfer coefficients for evaporator and condenser are ranging of 200–400 and 450–2000 W/m"2 K. The maximum expander shaft power and electrical power are 2.78 kW and 2.01 kW, respectively, while the maximum system generating efficiency is 3.25%. Moreover, the tested thermal efficiency presents a slight decrease trend with mass flow rate.

  20. 3D printing of microtube in solid phantom to simulate tissue oxygenation and perfusion (Conference Presentation)

    Science.gov (United States)

    Lv, Xiang; Xue, Yue; Wang, Haili; Shen, Shu Wei; Zhou, Ximing; Liu, Guangli; Dong, Erbao; Xu, Ronald X.

    2017-03-01

    Tissue-simulating phantoms with interior vascular network may facilitate traceable calibration and quantitative validation of many medical optical devices. However, a solid phantom that reliably simulates tissue oxygenation and blood perfusion is still not available. This paper presents a new method to fabricate hollow microtubes for blood vessel simulation in solid phantoms. The fabrication process combines ultraviolet (UV) rapid prototyping technique with fluid mechanics of a coaxial jet flow. Polydimethylsiloxane (PDMS) and a UV-curable polymer are mixed at the designated ratio and extruded through a coaxial needle device to produce a coaxial jet flow. The extruded jet flow is quickly photo-polymerized by ultraviolet (UV) light to form vessel-simulating solid structures at different sizes ranging from 700 μm to 1000 μm. Microtube structures with adequate mechanical properties can be fabricated by adjusting material compositions and illumination intensity. Curved, straight and stretched microtubes can be formed by adjusting the extrusion speed of the materials and the speed of the 3D printing platform. To simulate vascular structures in biologic tissue, we embed vessel-simulating microtubes in a gel wax phantom of 10 cm x10 cm x 5 cm at the depth from 1 to 2 mm. Bloods at different oxygenation and hemoglobin concentration levels are circulated through the microtubes at different flow rates in order to simulate different oxygenation and perfusion conditions. The simulated physiologic parameters are detected by a tissue oximeter and a laser speckle blood flow meter respectively and compared with the actual values. Our experiments demonstrate that the proposed 3D printing process is able to produce solid phantoms with simulated vascular networks for potential applications in medical device calibration and drug delivery studies.

  1. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S. [Samsung Medical Center, Seoul (Korea, Republic of); Lee, Kyung Han; Lee, Myung Chul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1996-03-15

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p<0.05). There was no correlation between the severity of the motor abnormality and any of the regional cerebral perfusion indices (p>0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  2. Computed Tomography (CT) Perfusion in Abdominal Cancer

    DEFF Research Database (Denmark)

    Hansen, Martin Lundsgaard; Norling, Rikke; Lauridsen, Carsten

    2013-01-01

    Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed...

  3. Effects of ethanol and hyperosmotic perfusates on albumin synthesis and release

    International Nuclear Information System (INIS)

    Rothschild, M.A.; Oratz, M.; Schreiber, S.S.; Mongelli, J.

    1986-01-01

    Sucrose and ethanol inhibit albumin synthesis; sucrose via an osmotic mechanism and ethanol during its metabolism. The present study was undertaken to compare the effects of both of these agents on albumin synthesis and secretion, and to see if ethanol inhibition could be related to an osmotic effect. Male, fed rabbits served as liver donors in all studies. There were a total of 35 studies: 13 control; 10 ethanol (39 to 52 mM); 4 cycloheximide (0.5 mM), and 8 sucrose (1%). Plasma volume was measured with 125 I-albumin (human) and extracellular volume measured with either /sup 99m/Tc diethylenetriamine pentaacetic acid or [ 14 C]sucrose. During perfusion, rabbit albumin content in the perfusate was measured immunologically every 15 to 30 min for 225 min. Interstitial albumin efflux was measured by the rate of appearance in the perfusate of 125 I-albumin given to 10 other rabbits 3 days prior to hepatic removal and perfusion. During the initial 75 min of perfusion, 74% of the in vivo equilibrated exchangeable 125 I-albumin appeared in the perfusate, and during this period the rabbit albumin that entered the perfusate was taken to represent efflux from the interstitial volume plus synthesis. Rabbit albumin appearing in the perfusate during the later period of 150 min was taken to represent mainly synthesis and was used to calculate the amount of albumin that would be synthesized in 75 min. The difference between these two values would be hepatic interstitial albumin appearing in the perfusate

  4. Myocardial perfusion abnormality and chest pain in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Narita, Michihiro; Kurihara, Tadashi; Murano, Kenichi; Usami, Masahisa

    1991-01-01

    To investigate the role of myocardial ischemia in the development of chest pain in patients with hypertrophic cardiomyopathy (HCM), exercise stress (Ex) redistribution myocardial single photon emission CT's (SPECT's) with thallium-201 (Tl) were obtained in 27 patients with HCM. In all patients, coronary arteries were normal arteriographically. Patients were classified into NYHA Class I, II and III according to the frequency and severity of the chest pain during daily life. In these 3 groups, age, sex and intraventricular septal thickness measured by echocardiography were not different. Types of myocardial perfusion obtained by myocardial SPECT's were divided into 5: (1) normal perfusion, (2) no perfusion defect with abnormal myocardial Tl washout rate (WOR) during 3 hours (<30%) [Def(-)/WORabn], (3) reversible perfusion defect (RD), (4) fixed defect with abnormal WOR (FD/WORabn), and (5) fixed defect with normal WOR (FD/WORnl). In 14 patients of Class I, 9 patients (64%) showed normal perfusion but the rest showed perfusion abnormality (def(-)/WORabn in 3 and RD in 2). In Class II and III, all patients showed perfusion abnormalities of RD, FD/WORabn or FD/WORnl. As the functional class progressed from Class II to III, the ratio of fixed defect (both WORnl and WORabn) to RD increased, but it was not statistically significant. In 2 patients in whom Ex SPECT's were repeated because of the progression of the chest pain, the severity of the perfusion abnormality also progressed. Perfusion abnormalities were observed most frequently in anterior (35%), then inferior/posterior (20%) and septal wall (18%). The frequency of Ex induced ECG abnormalities (ST-depression or T wave changes) increased as the NYHA Class progressed (Class III vs I p<0.05). These findings suggested the following: chest pain in patients with HCM relates to the myocardial ischemia which may originate in the myocardial small arteries, and when the lesions progress myocardial necrosis may ensue. (author)

  5. The incidence and functional consequences of RT-associated cardiac perfusion defects

    International Nuclear Information System (INIS)

    Marks, Lawrence B.; Yu Xiaoli; Prosnitz, Robert G.; Zhou Sumin; Hardenbergh, Patricia H.; Blazing, Michael; Hollis, Donna; Lind, Pehr; Tisch, Andrea; Wong, Terence Z.; Borges-Neto, Salvador

    2005-01-01

    Purpose: Radiation therapy (RT) for left-sided breast cancer has been associated with cardiac dysfunction. We herein assess the temporal nature and volume dependence of RT-induced left ventricular perfusion defects and whether these perfusion defects are related to changes in cardiac wall motion or alterations in ejection fraction. Methods: From 1998 to 2001, 114 patients were enrolled onto an IRB-approved prospective clinical study to assess changes in regional and global cardiac function after RT for left-sided breast cancer. Patients were imaged 30 to 60 minutes after injection of technetium 99m sestamibi or tetrofosmin. Post-RT perfusion scans were compared with the pre-RT studies to assess for RT-induced perfusion defects as well as functional changes in wall motion and ejection fraction. Two-tailed Fisher's exact test and the Cochran-Armitage test for linear trends were used for statistical analysis. Results: The incidence of new perfusion defects 6, 12, 18, and 24 months after RT was 27%, 29%, 38%, and 42%, respectively. New defects occurred in approximately 10% to 20% and 50% to 60% of patients with less than 5%, and greater than 5%, of their left ventricle included within the RT fields, respectively (p = 0.33 to 0.00008). The rates of wall motion abnormalities in patients with and without perfusion defects were 12% to 40% versus 0% to 9%, respectively; p values were 0.007 to 0.16, depending on the post-RT interval. Conclusions: Radiation therapy causes volume-dependent perfusion defects in approximately 40% of patients within 2 years of RT. These perfusion defects are associated with corresponding wall-motion abnormalities. Additional study is necessary to better define the long-term functional consequences of RT-induced perfusion defects

  6. MRI and MRA of kidney transplants - evaluation of vessels and perfusion

    International Nuclear Information System (INIS)

    Wiesner, W.; Pfammatter, T.; Krestin, G.P.; Debatin, J.F.

    1998-01-01

    Purpose: To document the value of fast contrast enhanced-sequences in the assessment of the vascular supply and parenchymal perfusion in renal transplants. Patients: 18 recipients of a renal transplant were examined with a 1.5-Tesla-MR-system. The protocol included fast contrast enhanced 3D MR angiography and coronal 2D GRE sequences. The transplant artery and vein were assessed as well as regional parenchymal perfusion. Results: 3D MRA detected three transplant artery stenoses and one occlusion. In addition, two renal vein thromboses and one compression were identified. Perfusion deficits were documented in 8 renal transplants: Renal infarction (n=4), cortical necrosis (n=2), acute tubular necrosis (n=1) and venous ischemia (n=1). Fluid collections were documented as well as dilatation of the collecting system and abnormalities of the surrounding tissues. Conclusion: Contrast enhanced MRI and MRA permit a comprehensive assessment of renal transplants without inducing nephrotoxicity. (orig.) [de

  7. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo

    2010-01-01

    radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators......Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over......, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices...

  8. Brain Perfusion Changes in Intracerebral Hemorrhage

    International Nuclear Information System (INIS)

    Mititelu, R.; Mazilu, C.; Ghita, S.; Rimbu, A.; Marinescu, G.; Codorean, I.; Bajenaru, O.

    2006-01-01

    Full text: Purpose: Despite the latest advances in medical treatment and neuro critical care, patients suffering spontaneous intracerebral hemorrhage (SICH) still have a very poor prognosis, with a greater mortality and larger neurological deficits at the survivors than for ischemic stroke. Many authors have shown that there are many mechanisms involved in the pathology of SICH: edema, ischemia, inflammation, apoptosis. All of these factors are affecting brain tissue surrounding hematoma and are responsible of the progressive neurological deterioration; most of these damages are not revealed by anatomical imaging techniques. The aim of our study was to asses the role of brain perfusion SPECT in demonstrating perfusion changes in SICH patients. Method: 17 SICH pts were studied. All pts underwent same day CT and brain SPECT with 99mTcHMPAO, 24h-5d from onset of stroke. Results: 14/17 pts showed a larger perfusion defect than expected after CT. In 2 pts hematoma diameter was comparable on CT and SPECT; 1pt had quasinormal aspect of SPECT study. In pts with larger defects, SPECT revealed a large cold spot with similar size compared with CT, and a surrounding hypo perfused area. 6/17 pts revealed cortical hyper perfusion adjacent to hypo perfused area and corresponding to a normal-appearing brain tissue on CT. In 3 pts we found crossed cerebellar diaskisis.In 2 pts we found cortical hypo perfused area in the contralateral cortex, with normal appearing brain tissue on CT. Conclusions: Brain perfusion SPECT revealed different types of perfusion changes in the brain tissue surrounding hematoma. These areas contain viable brain tissue that may be a target for future ne uroprotective strategies. Further studies are definitely required to demonstrate prognostic significance of these changes, but we can conclude that brain perfusion SPECT can play an important role in SICH, by early demonstrating functional changes responsible of clinical deterioration, thus allowing prompt

  9. Determining the spill flow discharge of combined sewer overflows using rating curves based on computational fluid dynamics instead of the standard weir equation.

    Science.gov (United States)

    Fach, S; Sitzenfrei, R; Rauch, W

    2009-01-01

    It is state of the art to evaluate and optimise sewer systems with urban drainage models. Since spill flow data is essential in the calibration process of conceptual models it is important to enhance the quality of such data. A wide spread approach is to calculate the spill flow volume by using standard weir equations together with measured water levels. However, these equations are only applicable to combined sewer overflow (CSO) structures, whose weir constructions correspond with the standard weir layout. The objective of this work is to outline an alternative approach to obtain spill flow discharge data based on measurements with a sonic depth finder. The idea is to determine the relation between water level and rate of spill flow by running a detailed 3D computational fluid dynamics (CFD) model. Two real world CSO structures have been chosen due to their complex structure, especially with respect to the weir construction. In a first step the simulation results were analysed to identify flow conditions for discrete steady states. It will be shown that the flow conditions in the CSO structure change after the spill flow pipe acts as a controlled outflow and therefore the spill flow discharge cannot be described with a standard weir equation. In a second step the CFD results will be used to derive rating curves which can be easily applied in everyday practice. Therefore the rating curves are developed on basis of the standard weir equation and the equation for orifice-type outlets. Because the intersection of both equations is not known, the coefficients of discharge are regressed from CFD simulation results. Furthermore, the regression of the CFD simulation results are compared with the one of the standard weir equation by using historic water levels and hydrographs generated with a hydrodynamic model. The uncertainties resulting of the wide spread use of the standard weir equation are demonstrated.

  10. Disposing of fluid wastes

    International Nuclear Information System (INIS)

    Bradley, J.S.

    1984-01-01

    Toxic liquid waste, eg liquid radioactive waste, is disposed of by locating a sub-surface stratum which, before removal of any fluid, has a fluid pressure in the pores thereof which is less than the hydrostatic pressure which is normal for a stratum at that depth in the chosen area, and then feeding the toxic liquid into the stratum at a rate such that the fluid pressure in the stratum never exceeds the said normal hydrostatic pressure. (author)

  11. Effect of myocardial perfusion and metabolic interventions on cardiac kinetics of phenylpentadecanoic acid (IPPA) I 123

    Energy Technology Data Exchange (ETDEWEB)

    Reske, S.N.; Schoen, S.; Schmitt, W.; Knopp, R.; Winkler, C.; Machulla, H.J.

    1986-08-01

    The effect of regional myocardial perfusion and flow-independent adrenergic stimulation, as well as lactate-mediated inhibition of cardiac lipolysis, on cardiac IPPA uptake and metabolism was examined in canine hearts (flow studies) and in the isolated perfused Langendorff rat heart (metabolic interventions). In both normal and ischaemic myocardium, local perfusion is a major determinant of cardiac IPPA uptake. In pacing-induced hyperaemia, the strict flow-dependence of cardiac IPPA uptake is not preserved. Adrenergic stimulation raises the rate of oxidation of both palmitic acid /sup 14/C and IPPA. This change is reflected by increased metabolite production released into the perfusate and radioactivity clearance recorded externally. Lactate in high concentrations exerts the opposite effect on cardiac free fatty acid oxidation. IPPA is stored in this condition preferentially in tissue phospholipids and triglycerides.

  12. Effect of myocardial perfusion and metabolic interventions on cardiac kinetics of phenylpentadecanoic acid (IPPA) I 123

    International Nuclear Information System (INIS)

    Reske, S.N.; Schoen, S.; Schmitt, W.; Knopp, R.; Winkler, C.; Machulla, H.J.

    1986-01-01

    The effect of regional myocardial perfusion and flow-independent adrenergic stimulation, as well as lactate-mediated inhibition of cardiac lipolysis, on cardiac IPPA uptake and metabolism was examined in canine hearts (flow studies) and in the isolated perfused Langendorff rat heart (metabolic interventions). In both normal and ischaemic myocardium, local perfusion is a major determinant of cardiac IPPA uptake. In pacing-induced hyperaemia, the strict flow-dependence of cardiac IPPA uptake is not preserved. Adrenergic stimulation raises the rate of oxidation of both palmitic acid 14 C and IPPA. This change is reflected by increased metabolite production released into the perfusate and radioactivity clearance recorded externally. Lactate in high concentrations exerts the opposite effect on cardiac free fatty acid oxidation. IPPA is stored in this condition preferentially in tissue phospholipids and triglycerides. (orig.)

  13. Assessment of right liver graft perfusion effectiveness between one and two-catheter infusion methods.

    Science.gov (United States)

    Jung, Bo-Hyun; Hwang, Shin; Ha, Tae-Yong; Song, Gi-Won; Jung, Dong-Hwan; Kim, Ki-Hun; Ahn, Chul-Soo; Moon, Deok-Bog; Park, Gil-Chun; Kang, Sung-Hwa; Yoon, Young-In; Lee, Sung-Gyu

    2014-05-01

    Conventional graft perfusion method using one small-caliber catheter takes a relatively long time for right liver graft perfusion, thus some modification is needed. In this study, we intended to assess the effectiveness of right liver graft perfusion methods through comparison of different infusion catheters. The study consisted of two parts including one bench experiment to obtain data of hydraulic infusion and one clinical trial of 40 cases on graft perfusion with one- versus two-catheter infusion methods. These two graft infusion methods were compared in terms of the perfusion time and washing-out efficiency. At bench experiment, the infusion flow rate and infusion pressure were 3.3 ml/sec and 1.9 cmH20 in one blood transfusion catheter group, and 11.7 ml/sec and 3.1 cmH20 in single transurethral resection of prostate irrigation catheter group, and 6.6 ml/sec and 2.0 cmH20 in two blood transfusion catheters group, respectively. In clinical trial with 40 right liver grafts, two-catheter group had a shorter graft portal perfusion time for the first 2 L of histidine-tryptophan-ketoglutarate (HTK) solution than the conventional one-catheter group (375±25 seconds vs. 662±34 seconds; p=0.001) and a lower rate of incomplete blood washing-out after the initial 2 L portal perfusion (40% vs. 85%; p=0.03). The two-catheter infusion method appears to be more effective than the conventional one-catheter infusion method for right liver graft perfusion at the back table. Large size of right liver grafts seems to be its good indication.

  14. Vasoactive mediators and splanchnic perfusion.

    Science.gov (United States)

    Reilly, P M; Bulkley, G B

    1993-02-01

    To provide an overview of the splanchnic hemodynamic response to circulatory shock. Previous studies performed in our own laboratory, as well as a computer-assisted search of the English language literature (MEDLINE, 1966 to 1991), followed by a selective review of pertinent articles. Studies were selected that demonstrated relevance to the splanchnic hemodynamic response to circulatory shock, either by investigating the pathophysiology or documenting the sequelae. Article selection included clinical studies as well as studies in appropriate animal models. Pertinent data were abstracted from the cited articles. The splanchnic hemodynamic response to circulatory shock is characterized by a selective vasoconstriction of the mesenteric vasculature mediated largely by the renin-angiotensin axis. This vasospasm, while providing a natural selective advantage to the organism in mild-to-moderate shock (preserving relative perfusion of the heart, kidneys, and brain), may, in more severe shock, cause consequent loss of the gut epithelial barrier, or even hemorrhagic gastritis, ischemic colitis, or ischemic hepatitis. From a physiologic standpoint, nonpulsatile cardiopulmonary bypass, a controlled form of circulatory shock, has been found experimentally to significantly increase circulating levels of angiotensin II, the hormone responsible for this selective splanchnic vasoconstriction. While angiotensin II has been viewed primarily as the mediator responsible for the increased total vascular resistance seen during (and after) cardiopulmonary bypass, it may also cause the disproportionate decrease in mesenteric perfusion, as measured in human subjects by intraluminal gastric tonometry and galactose clearance by the liver, as well as the consequent development of the multiple organ failure syndrome seen in 1% to 5% of patients after cardiac surgery.

  15. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    International Nuclear Information System (INIS)

    Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S.; Lee, Kyung Han; Lee, Myung Chul

    1996-01-01

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p 0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  16. Computerized analysis of brain perfusion parameter images

    International Nuclear Information System (INIS)

    Turowski, B.; Haenggi, D.; Wittsack, H.J.; Beck, A.; Aurich, V.

    2007-01-01

    Purpose: The development of a computerized method which allows a direct quantitative comparison of perfusion parameters. The display should allow a clear direct comparison of brain perfusion parameters in different vascular territories and over the course of time. The analysis is intended to be the basis for further evaluation of cerebral vasospasm after subarachnoid hemorrhage (SAH). The method should permit early diagnosis of cerebral vasospasm. Materials and Methods: The Angiotux 2D-ECCET software was developed with a close cooperation between computer scientists and clinicians. Starting from parameter images of brain perfusion, the cortex was marked, segmented and assigned to definite vascular territories. The underlying values were averages for each segment and were displayed in a graph. If a follow-up was available, the mean values of the perfusion parameters were displayed in relation to time. The method was developed under consideration of CT perfusion values but is applicable for other methods of perfusion imaging. Results: Computerized analysis of brain perfusion parameter images allows an immediate comparison of these parameters and follow-up of mean values in a clear and concise manner. Values are related to definite vascular territories. The tabular output facilitates further statistic evaluations. The computerized analysis is precisely reproducible, i. e., repetitions result in exactly the same output. (orig.)

  17. Relations between passage rates of rumen fluid and particulate matter and foam production in rumen contents of cattle fed on different diets ad lib.

    Science.gov (United States)

    Okine, E K; Mathison, G W; Hardin, R T

    1989-03-01

    1. A group of six cattle, three of which had a non-bloating history (group A) and had been ruminally cannulated for the previous 2 years, and three with a history of being bloat-prone (group B) and which had been ruminally cannulated only 3 months before the study, were fed ad lib. on chopped lucerne (Medicago sativa) hay, lucerne pellets, or a 100 g chopped hay and 900 g rolled barley grain/kg diet over three periods of 30 d each. Flow of rumen digesta, by reference to CoEDTA and chromium-mordanted fibres, and foam production from samples of rumen contents were measured. 2. Samples of rumen contents (50 ml) from group A produced foam heights of 150 and 60 mm, 2 and 4 h after feeding respectively, compared with 240 and 150 mm for group B (P less than 0.05). 3. The fractional passage rate of the 1-2 mm particles mordanted with Cr did not differ (P greater than 0.05) between groups. 4. The fractional outflow rates (FOR) for CoEDTA 0-2 h and 2-7 h after feed was offered were 0.205 and 0.160/h for group A and 0.093 and 0.086/h for group B respectively (P less than 0.05). 5. Rumen-fluid FOR 0-2 h and 2-7 h after provision of feed were significantly (P less than 0.05) inversely correlated (r -0.74 and -0.85 respectively) with the amount of foam produced from rumen contents at these times.

  18. 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)

  19. Perfusion-induced changes in cardiac contractility depend on capillary perfusion.

    Science.gov (United States)

    Dijkman, M A; Heslinga, J W; Sipkema, P; Westerhof, N

    1998-02-01

    The perfusion-induced increase in cardiac contractility (Gregg phenomenon) is especially found in heart preparations that lack adequate coronary autoregulation and thus protection of changes in capillary pressure. We determined in the isolated perfused papillary muscle of the rat whether cardiac muscle contractility is related to capillary perfusion. Oxygen availability of this muscle is independent of internal perfusion, and perfusion may be varied or even stopped without loss of function. Muscles contracted isometrically at 27 degrees C (n = 7). During the control state stepwise increases in perfusion pressure resulted in all muscles in a significant increase in active tension. Muscle diameter always increased with increased perfusion pressure, but muscle segment length was unaffected. Capillary perfusion was then obstructed by plastic microspheres (15 microns). Flow, at a perfusion pressure of 66.6 +/- 26.2 cmH2O, reduced from 17.6 +/- 5.4 microliters/min in the control state to 3.2 +/- 1.3 microliters/min after microspheres. Active tension developed by the muscle in the unperfused condition before microspheres and after microspheres did not differ significantly (-12.8 +/- 29.4% change). After microspheres similar perfusion pressure steps as in control never resulted in an increase in active tension. Even at the two highest perfusion pressures (89.1 +/- 28.4 and 106.5 +/- 31.7 cmH2O) that were applied a significant decrease in active tension was found. We conclude that the Gregg phenomenon is related to capillary perfusion.

  20. Hepatic Arterial Perfusion Scintigraphy with '99mTc-Macroaggregated Albumin in Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Kim, Gang Deuk; Sohn, Kwang Joon; Min, Kyung Yoon; Kwon, Young Mi; Kim, Chang Guhn; Noh, Byung Suk; Won, Jong Jin

    1994-01-01

    Hepatic arterial perfusion scintigraphy with '9 9m Tc macroggregated albumin (HAPS) study was carried out in 16 patients with hepatocellular carcinoma (HCC) and in six patients without liver tumor to evaluate HAPS findings of hepatocellular carcinoma and use fullness of HAPS. HAPS with planar and SPECT study were performed in 22 patients after conventional hepatic or celiac arteriography. For HAPS study, 4 5 mCi of MAA mixed with 2 ml of saline was injected into proper hepatic artery or its distal branches at the rate of approximately 1 ml/sec. We analysed 21 HCCs over 2 cm in diameter(average diameter: 6.4 cm) and 17 of 21 HCCs were over 4 cm in diameter. CT, sonography and angiography were performed within two week in all 16 patients and liver scan was performed in 12 patients. Three different pattern of tumor perfusion were observed in 16 patients with HCC. 1) diffuse increased perfusion in 16 of 21(76%) 2) increased peripheral perfusion in 4 of 21(19%) 3) diffuse decreased perfusion in 1 of 21 (5%) Arteriovenous shunt indicated by lung uptake of MAA were observed in 9 of 16 (56% ). In contrast, angiography demonstrates arteriovenous shunt in 2 of 16 (13%). There was no accumulation of radioactivity on RRC blood pool scan in all six patients with HCC examined. HAPS is useful study in evaluation of perfusion pattern or vascularity of HCC and in detection of arteriovenous shunt.

  1. Discrepancy between microsphere and diffusible tracer estimates of perfusion to ischemic myocardium

    International Nuclear Information System (INIS)

    Yoshida, S.; Akizuki, S.; Gowski, D.; Downey, J.M.

    1985-01-01

    This study critically tests the ability of microspheres to accurately measure perfusion to ischemic myocardium. The left anterior descending coronary artery was cannulated and perfused with arterial blood. The perfusion line was clamped, and a sidearm between the clamp and the cannula was opened to the atmosphere, allowing blood to flow retrograde from the distal segment of the artery. Measurement of regional blood flow during retrograde flow diversion with 15-micron microspheres revealed essentially zero flow to the perfused segment (0.005 ml X min-1 X g-1). Measurements under the same conditions by either 86 Rb uptake or 133 Xe washout revealed that an appreciable perfusion of the tissue persisted during retrograde flow diversion (0.043 and 0.11 ml X min-1 X g-1, respectively, for the 2 methods). Thus, the authors have identified a condition during which microspheres indicate zero flow to the tissue but diffusible tracers can both be washed in and washed out at a brisk rate. They conclude that with simple occlusion there is a hidden component of perfusion to an ischemic zone that cannot be measured by microspheres, causing them to underestimate flow by about 25% in that condition

  2. Pulmonary O2 transfer during pulsatile and non-pulsatile perfusion.

    Science.gov (United States)

    Hauge, A; Nicolaysen, G

    1980-07-01

    The importance of the perfusion pattern for the oxygen transfer has been examined in isolated rabbit lungs perfused with plasma at constant volume inflow. The lungs were ventilated with constant tidal volume and constant end-expiratory pressure. Following a standardized rise in FIO2 the rate of rise in pulmonary venous PO2 (delta PO2/delta t) was measured during alternately pulsatile and non-pulsatile perfusion in normal lungs and in lungs made edematous by elevation of left atrial pressure. In normal lungs there was no difference in delta PO2/delta t when the two modes of perfusion were compared. In edematous lungs delta PO/delta t was statistically higher during pulsatile perfusion, indicating a beneficial effect of flow- and pressure pulsations, e.g. a better distribution of V/Q ratios throughout the lungs. In a separate series of expts. the advancement of a high O2 front through the airways was measured, and the two perfusion patterns compared. Since no difference was found, we suggest that the phenomenon of "cardiogenic gas mixing" in the airways in vivo is a result of a direct action of the heart on the lungs rather than arterial pulsations.

  3. Myocardial perfusion scintigraphy - possibilities of diagnosing CAD

    International Nuclear Information System (INIS)

    Tsonevska, A.

    1998-01-01

    A reviewing the diagnostic methods used in the intricate process of evaluating CAD patients in a attempt to establish the role played by radionuclide methods in the diagnostic strategy is done. The perfusion cardiotropic radiopharmaceuticals used and the various methods of evaluating myocardial are discussed. Although 210 Tl-chloride is the most widely used myocardial perfusion agent, recently 99m Tc-MIBI is proposed as an alternative because of its advantages. Myocardial perfusion assessment is done by various techniques depending on the specific aim, each of them having its proper advantages and shortcomings. The inference is reached that regardless of the routine practical implementation of myocardial perfusion scintigraphy and comprehensive studies along this line in course, there are problems still not well enough clarified awaiting solution

  4. 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

  5. MRI of pulmonary perfusion; MRT der Lungenperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Fink, C. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen (Germany). Institut fuer Klinische Radiologie; Deutsches Krebsforschungszentrum (DKFZ), Abteilung Radiologie, Heidelberg (Germany); Risse, F.; Semmler, W. [Deutsches Krebsforschungszentrum (DKFZ), Abteilung Medizinische Physik in der Radiologie, Heidelberg (Germany); Schoenberg, S.O.; Reiser, M.F. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen (Germany). Institut fuer Klinische Radiologie; Kauczor, H.-U. [Deutsches Krebsforschungszentrum (DKFZ), Abteilung Radiologie, Heidelberg (Germany)

    2006-04-15

    Lung perfusion is a crucial prerequisite for effective gas exchange. Quantification of pulmonary perfusion is important for diagnostic considerations and treatment planning in various diseases of the lungs. Besides disorders of pulmonary vessels such as acute pulmonary embolism and pulmonary hypertension, these also include diseases of the respiratory tract and lung tissue as well as pulmonary tumors. This contribution presents the possibilities and technical requirements of MRI for diagnostic work-up of pulmonary perfusion. (orig.) [German] Die Perfusion der Lunge ist eine entscheidende Voraussetzung fuer einen effektiven Gasaustausch. Die Bestimmung der Lungenperfusion ist bei verschiedenen Erkrankungen der Lunge fuer Diagnostik und Therapieplanung bedeutsam. Hierzu zaehlen neben Erkrankungen der Lungengefaesse wie akute Lungenembolie und pulmonale Hypertension ebenso Erkrankungen der Atemwege, des Lungengeruests und Lungentumoren. In diesem Beitrag werden die Moeglichkeiten und technischen Voraussetzungen der MRT zur Diagnostik der Lungenperfusion dargestellt. (orig.)

  6. Ictal cerebral perfusion patterns in partial epilepsy: SPECT subtraction

    International Nuclear Information System (INIS)

    Lee, Hyang Woon; Hong, Seung Bong; Tae, Woo Suk; Kim, Sang Eun; Seo, Dae Won; Jeong, Seung Cheol; Yi, Ji Young; Hong, Seung Chyul

    2000-01-01

    To investigate the various ictal perfusion patterns and find the relationships between clinical factors and different perfusion patterns. Interictal and ictal SPECT and SPECT subtraction were performed in 61 patients with partial epilepsy. Both positive images showing ictal hyperperfusion and negative images revealing ictal hypoperfusion were obtained by SPECT subtraction. The ictal perfusion patterns of subtracted SPECT were classified into focal hyperperfusion, hyperperfusion-plus, combined hyperperfusion-hypoperfusion, and focal hypoperfusion only. The concordance rates with epileptic focus were 91.8% in combined analysis of ictal hyperperfusion and hypoperfusion images of subtracted SPECT, 85.2% in hyperperfusion images only of subtracted SPECT, and 68.9% in conventional ictal SPECT analysis. Ictal hypoperfusion occurred less frequently in temporal lobe epilepsy (TLE) than extratemporal lobe epilepsy. Mesial temporal hyperperfusion alone was seen only in mesial TLE while lateral temporal hyperperfusion alone was observed only in neocortical TLE. Hippocampal sclerosis had much lower incidence of ictal hypoperfusion than any other pathology. Some patients showed ictal hypoperfusion at epileptic focus with ictal hyperperfusion in the neighboring brain regions where ictal discharges propagated. Hypoperfusion as well as hyperperfusion in ictal SPECT should be considered for localizing epileptic focus. Although the mechanism of ictal hypoperfusion could be an intra-ictal early exhaustion of seizure focus or a steal phenomenon by the propagation of ictal discharges to adjacent brain areas, further study is needed to elucidate it.=20

  7. Ictal cerebral perfusion patterns in partial epilepsy: SPECT subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyang Woon; Hong, Seung Bong; Tae, Woo Suk; Kim, Sang Eun; Seo, Dae Won; Jeong, Seung Cheol; Yi, Ji Young; Hong, Seung Chyul [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    2000-06-01

    To investigate the various ictal perfusion patterns and find the relationships between clinical factors and different perfusion patterns. Interictal and ictal SPECT and SPECT subtraction were performed in 61 patients with partial epilepsy. Both positive images showing ictal hyperperfusion and negative images revealing ictal hypoperfusion were obtained by SPECT subtraction. The ictal perfusion patterns of subtracted SPECT were classified into focal hyperperfusion, hyperperfusion-plus, combined hyperperfusion-hypoperfusion, and focal hypoperfusion only. The concordance rates with epileptic focus were 91.8% in combined analysis of ictal hyperperfusion and hypoperfusion images of subtracted SPECT, 85.2% in hyperperfusion images only of subtracted SPECT, and 68.9% in conventional ictal SPECT analysis. Ictal hypoperfusion occurred less frequently in temporal lobe epilepsy (TLE) than extratemporal lobe epilepsy. Mesial temporal hyperperfusion alone was seen only in mesial TLE while lateral temporal hyperperfusion alone was observed only in neocortical TLE. Hippocampal sclerosis had much lower incidence of ictal hypoperfusion than any other pathology. Some patients showed ictal hypoperfusion at epileptic focus with ictal hyperperfusion in the neighboring brain regions where ictal discharges propagated. Hypoperfusion as well as hyperperfusion in ictal SPECT should be considered for localizing epileptic focus. Although the mechanism of ictal hypoperfusion could be an intra-ictal early exhaustion of seizure focus or a steal phenomenon by the propagation of ictal discharges to adjacent brain areas, further study is needed to elucidate it.

  8. Vicarious audiovisual learning in perfusion education.

    Science.gov (United States)

    Rath, Thomas E; Holt, David W

    2010-12-01

    Perfusion technology is a mechanical and visual science traditionally taught with didactic instruction combined with clinical experience. It is difficult to provide perfusion students the opportunity to experience difficult clinical situations, set up complex perfusion equipment, or observe corrective measures taken during catastrophic events because of patient safety concerns. Although high fidelity simulators offer exciting opportunities for future perfusion training, we explore the use of a less costly low fidelity form of simulation instruction, vicarious audiovisual learning. Two low fidelity modes of instruction; description with text and a vicarious, first person audiovisual production depicting the same content were compared. Students (n = 37) sampled from five North American perfusion schools were prospectively randomized to one of two online learning modules, text or video.These modules described the setup and operation of the MAQUET ROTAFLOW stand-alone centrifugal console and pump. Using a 10 question multiple-choice test, students were assessed immediately after viewing the module (test #1) and then again 2 weeks later (test #2) to determine cognition and recall of the module content. In addition, students completed a questionnaire assessing the learning preferences of today's perfusion student. Mean test scores from test #1 for video learners (n = 18) were significantly higher (88.89%) than for text learners (n = 19) (74.74%), (p audiovisual learning modules may be an efficacious, low cost means of delivering perfusion training on subjects such as equipment setup and operation. Video learning appears to improve cognition and retention of learned content and may play an important role in how we teach perfusion in the future, as simulation technology becomes more prevalent.

  9. Improved exercise myocardial perfusion during lidoflazine therapy

    International Nuclear Information System (INIS)

    Shapiro, W.; Narahara, K.A.; Park, J.

    1983-01-01

    Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a study of 6 patients with severe classic angina pectoris, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise

  10. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Jensen, L.T.; Larsson, H.B.

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...... myocardial perfusion imaging with MR contrast agents: methods, validation and experiences from clinical studies. Unresolved issues still restrict the use of these techniques to research although clinical applications are within reach Udgivelsesdato: 2008/12/8...

  11. Ventilation-perfused studies using SPECT

    International Nuclear Information System (INIS)

    Zwijnenburg, A.

    1989-01-01

    A method for the quantitative analysis of ventilation-perfusion SPECT studies is decribed and an effort is made to evaluate its usefullness. The technical details of the emthod are described. In the the transaxial reconstructions of the tomographic studies the contour of the lungs is detected and regional values of lung volume, ventilation, perfusion and ventilation-perfusion ratios are calculated. The method is operator independent. The lung volume calculations from the SPECT studies are validated by comparing them with lung volume measurements using the helium dilution technique. A good correlation (r=0.91) was found between the two volumes. SPECT volume was greater than the volume measured with helium dilution, which was attributed to non-gas-containing structures in the. lungs. The use of ventilation-perfusion ratio SPECT is described to evaluate the effect of ionizing radiation on the lungs in patients treated with mantle field irradiation for Hodgkin's disease. Perfusion changes appear as early as 2 months after the start of irradiation. Ventilation changes appear later and relatively minor. No changes are seen outside the radiation portals. The ventilation-perfusion inequality in pulmonary sarcoidosis is treated. It is suggested that the decrease D LCO in these patients may be partly due to an even distribution of ventilation perfusion ratios. An effort is made to establish the properties of a new tracer used for the assessment of the metabolic function of the pulmonary endothelium. The lung uptake of I-123 IMP mimics the distribution of a perfusion tracer and it is suggested that this tracer may be useful for the early detection of pulmonary vascular damage, even when blood flow is still intact. Some aspects of the use of Kr-81m as a ventilation tracer are discussed as well as the effect of noise on Kr-81m SPECT reconstructions. (author). 146 refs.; 39 figs.; 8 tabs

  12. Rapid gated Thallium-201 perfusion SPECT - clinically feasible?

    International Nuclear Information System (INIS)

    Wadhwa, S.S.; Mansberg, R.; Fernandes, V.B.; Wilkinson, D.; Abatti, D.

    1998-01-01

    Full text: Standard dose energy window optimised Thallium-201 (Tl-201) SPECT has about half the counts of a standard dose from Technetium-99m Sestamibi (Tc99m-Mibi) gated perfusion SPECT. This study investigates the clinical feasibility of rapid energy window optimised Tl-201 gated perfusion SPECT (gated-TI) and compares quantitative left ventricular ejection fraction (LVEF) and visually assessed image quality for wall motion and thickening to analogous values obtained from Tc99m-Mibi gated perfusion SPECT (gated - mibi). Methods: We studied 60 patients with a rest gated Tl-201 SPECT (100 MBq, 77KeV peak, 34% window, 20 sec/projection) followed by a post stress gated Sestamibi SPECT (1GBq, 140KeV, 20% window, 20 sec/projection) separate dual isotope protocol. LVEF quantitation was performed using commercially available software (SPECTEF, General Electric). Visual grading of image quality for wall thickening and motion was performed using a three-point scale (excellent, good and poor). Results: LVEF for gated Tl-201 SPECT was 59.6 ± 12.0% (Mean ± SD). LVEF for gated Sestamibi SPECT was 60.4 ±11.4% (Mean ± SD). These were not significantly different (P=0.27, T-Test). There was good correlation (r=0.9) between gated-TI and gated-mibi LVEF values. The quality of gated-Tl images was ranked as excellent, good and poor in 12, 50 and 38% of the patients respectively. Image quality was better in gated-mibi SPECT, with ratings of 12, 62 and 26% respectively. Conclusion: Rapid gated Thallium-201 acquisition with energy window optimisation can be effectively performed on majority of patients and offers the opportunity to assess not only myocardial perfusion and function, as with Technetium based agents, but also viability using a single day one isotope protocol

  13. Tumor Vessel Compression Hinders Perfusion of Ultrasonographic Contrast Agents

    Directory of Open Access Journals (Sweden)

    Mirco Galiè

    2005-05-01

    Full Text Available Contrast-enhanced ultrasound (CEUS is an advanced approach to in vivo assessment of tumor vascularity and is being increasingly adopted in clinical oncology. It is based on 1- to 10 μm-sized gas microbubbles, which can cross the capillary beds of the lungs and are effective echo enhancers. It is known that high cell density, high transendothelial fluid exchange, and poorly functioning lymphatic circulation all provoke solid stress, which compresses vessels and drastically reduces tumor blood flow. Given their size, we supposed that the perfusion of microbubbles is affected by anatomic features of tumor vessels more than are contrast agents traditionally used in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI. Here, we compared dynamic information obtained from CEUS and DCE-MRI on two experimental tumor models exhibiting notable differences in vessel anatomy. We found that tumors with small, flattened vessels show a much higher resistance to microbubble perfusion than to MRI contrast agents, and appear scarcely vascularized at CEUS examination, despite vessel volume adequate for normal function. Thus, whereas CEUS alone could induce incorrect diagnosis when tumors have small or collapsed vessels, integrated analysis using CEUS and DCE-MRI allows in vivo identification of tumors with a vascular profile frequently associated with malignant phenotypes.

  14. Tumor Vessel Compression Hinders Perfusion of Ultrasonographic Contrast Agents1

    Science.gov (United States)

    Galiè, Mirco; D'Onofrio, Mirko; Montani, Maura; Amici, Augusto; Calderan, Laura; Marzola, Pasquina; Benati, Donatella; Merigo, Flavia; Marchini, Cristina; Sbarbati, Andrea

    2005-01-01

    Abstract Contrast-enhanced ultrasound (CEUS) is an advanced approach to in vivo assessment of tumor vascularity and is being increasingly adopted in clinical oncology. It is based on 1- to 10 µm-sized gas microbubbles, which can cross the capillary beds of the lungs and are effective echo enhancers. It is known that high cell density, high transendothelial fluid exchange, and poorly functioning lymphatic circulation all provoke solid stress, which compresses vessels and drastically reduces tumor blood flow. Given their size, we supposed that the perfusion of microbubbles is affected by anatomic features of tumor vessels more than are contrast agents traditionally used in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we compared dynamic information obtained from CEUS and DCE-MRI on two experimental tumor models exhibiting notable differences in vessel anatomy. We found that tumors with small, flattened vessels show a much higher resistance to microbubble perfusion than to MRI contrast agents, and appear scarcely vascularized at CEUS examination, despite vessel volume adequate for normal function. Thus, whereas CEUS alone could induce incorrect diagnosis when tumors have small or collapsed vessels, integrated analysis using CEUS and DCE-MRI allows in vivo identification of tumors with a vascular profile frequently associated with malignant phenotypes. PMID:15967105

  15. Quantitative perfusion imaging in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Zoellner, F.G.; Gaa, T.; Zimmer, F.; Ong, M.M.; Riffel, P.; Hausmann, D.; Schoenberg, S.O.; Weis, M.

    2016-01-01

    Magnetic resonance imaging (MRI) is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation. Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible. One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. Perfusion imaging by MRI can be performed by two approaches, arterial spin labeling (ASL) and dynamic contrast-enhanced (DCE) MRI. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium (Gd), as a tracer for calculating hemodynamic parameters. Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels. Such efforts are being promoted by the respective professional bodies. (orig.) [de

  16. Insulin degradation products from perfused rat kidney

    International Nuclear Information System (INIS)

    Duckworth, W.C.; Hamel, F.G.; Liepnieks, J.; Peavy, D.; Frank, B.; Rabkin, R.

    1989-01-01

    The kidney is a major site for insulin metabolism, but the enzymes involved and the products generated have not been established. To examine the products, we have perfused rat kidneys with insulin specifically iodinated on either the A14 or the B26 tyrosine. Labeled material from both the perfusate and kidney extract was examined by Sephadex G50 and high-performance liquid chromatography (HPLC). In perfusate from a filtering kidney, 22% of the insulin-sized material was not intact insulin on HPLC. With the nonfiltering kidney, 10.6% was not intact insulin. Labeled material from HPLC was sulfitolyzed and reinjected on HPLC. By use of 125 I-iodo(A14)-insulin, almost all the degradation products contained an intact A-chain. By use of 125 I-iodo(B26)-insulin, several different B-chain-cleaved products were obtained. The material extracted from the perfused kidney was different from perfusate products but similar to intracellular products from hepatocytes, suggesting that cellular metabolism by kidney and liver are similar. The major intracellular product had characteristics consistent with a cleavage between the B16 and B17 amino acids. This product and several of the perfusate products are also produced by insulin protease suggesting that this enzyme is involved in the degradation of insulin by kidney

  17. CT perfusion study of neck lymph nodes

    International Nuclear Information System (INIS)

    Zhong Jin; Liu Jun; Hua Rui; Qiao Hui; Gong Yi

    2011-01-01

    Objective: To study the CT perfusion features of various lymph nodes in the neck. Methods: Dynamic perfusion CT scanning was performed in 83 neck lymph nodes proved by pathology, including tuberculosis lymph nodes, lymphoma and metastatic lymph nodes. The shapes, blood flow modes, and perfusion parameters of these lymph nodes were compared among 3 groups. Statistical analysis of L/T and CT perfusion parameters was performed by one-way ANOVA and LSD test. Results: The values of MTT of tuberculosis lymph nodes, lymphoma and metastatic lymph nodes were (28.13±5.08), (31.08±5.82), and (11.24±5.31) s, respectively. The MTT of metastatic lymph nodes was statistically lower than that of tuberculosis lymph nodes and lymphoma (P -1 · 100 g -1 , respectively. The values of BV were (24.68±2.84), (25.30±3.16), and (25.15± 8.81) ml·100 g -1 respectively. The values of TTP were (40.90±8.85), (40.67±6.45), and (40.98±6.62) s, respectively. There were no significant differences in L/T, BF, BV and TTP among tuberculosis lymph nodes, lymphoma and metastatic lymph nodes (P>0.05). Conclusion: CT perfusion, especially combination functional imaging with perfusion images may be helpful in judging the nature of neck lymph nodes. (authors)

  18. Uterine artery embolization for leiomyomas. Examination of correlation between degree of leiomyoma perfusion determined by enhanced MR i-Drive method and leiomyoma volume change on MR image

    International Nuclear Information System (INIS)

    Arimoto, Hiroshi; Yamamoto, Kazuhiro; Yamaguchi, Hiroyuki; Terai, Yoshito; Ohmichi, Masahide; Narabayashi, Isamu

    2007-01-01

    The objective of this study was to evaluate the correlations of leiomyoma volume reduction with the perfusion pattern of leiomyomas and signal intensity on T2-weighted images. Magnetic resonance (MR) imaging was performed on 11 patients with 35 symptomatic uterine leiomyomas before and 3 and 6 months after uterine artery embolization (UAE). The correlation between leiomyoma perfusion pattern and percent leiomyoma volume reduction was assessed. The mean percent leiomyoma volume reductions were 41.1% 3 months and 58.4% 6 months after UAE. The mean percent volume reductions of highly perfused leiomyomas were 58.6% 3 months and 85.7% 6 months after UAE. The reduction rates of poorly perfused leiomyomas were 37.9% 3 months and 49.1% 6 months after UAE. Well-perfused leiomyomas are more likely to reduce in leiomyoma volume. It is thought that a patient with a well-perfusion myoma is a good candidate for UAE. (author)

  19. Fluid Mechanics.

    Science.gov (United States)

    Drazin, Philip

    1987-01-01

    Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)

  20. Factors influencing cerebrospinal fluid and plasma HIV-1 RNA detection rate in patients with and without opportunistic neurological disease during the HAART era

    Directory of Open Access Journals (Sweden)

    Aleixo Agdemir W

    2007-12-01

    Full Text Available Abstract Background In the central nervous system, HIV replication can occur relatively independent of systemic infection, and intrathecal replication of HIV-1 has been observed in patients with HIV-related and opportunistic neurological diseases. The clinical usefulness of HIV-1 RNA detection in the cerebrospinal fluid (CSF of patients with opportunistic neurological diseases, or the effect of opportunistic diseases on CSF HIV levels in patients under HAART has not been well defined. We quantified CSF and plasma viral load in HIV-infected patients with and without different active opportunistic neurological diseases, determined the characteristics that led to a higher detection rate of HIV RNA in CSF, and compared these two compartments. Methods A prospective study was conducted on 90 HIV-infected patients submitted to lumbar puncture as part of a work-up for suspected neurological disease. Seventy-one patients had active neurological diseases while the remaining 19 did not. Results HIV-1 RNA was quantified in 90 CSF and 70 plasma samples. The HIV-1 RNA detection rate in CSF was higher in patients with neurological diseases, in those with a CD4 count lower than 200 cells/mm3, and in those not receiving antiretroviral therapy, as well as in patients with detectable plasma HIV-1 RNA. Median viral load was lower in CSF than in plasma in the total population, in patients without neurological diseases, and in patients with toxoplasmic encephalitis, while no significant difference between the two compartments was observed for patients with cryptococcal meningitis and HIV-associated dementia. CSF viral load was lower in patients with cryptococcal meningitis and neurotoxoplasmosis under HAART than in those not receiving HAART. Conclusion Detection of HIV-1 RNA in CSF was more frequent in patients with neurological disease, a CD4 count lower than 200 cells/mm3 and detectable plasma HIV-1. Median HIV-1 RNA levels were generally lower in CSF than in

  1. Determination of cerebral perfusion using magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ropele, S.

    1997-01-01

    This thesis deals with various magnetic resonance imaging methods to quantify cerebral blood flow. Special attention has been drawn to noninvasive methods. A new method based on the T1-shortening due to perfusion was developed using a multipoint inversion recovery sequence with alternating slice selective and non selective preparation. To study the influence of errors arising from partial volume effects with cerebrospinal fluid and from brain motion, numerous investigations have been performed on a clinical 1.5 Tesla scanner. In a second approach, the IVIM-method, which treats isotropic movement in the capillary network like diffusion, has been investigated. Since artifacts in phase encoding direction caused by brain motion are a common problem to most diffusion imaging techniques, a significant improvement has been achieved by the development and optimization of a single shot STEAM-sequence. This sequence proved to be less sensitive for motion artifacts, although a high signal to noise ratio has been preserved. (author)

  2. Thyroid perfusion imaging as a diagnostic tool in Graves' disease. Arterial spin labeling magnetic resonance imaging vs. colour-coded Doppler ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Muessig, K. [University Hospital of Duesseldorf (Germany). Dept. of Metabolic Diseases; Leibniz Center for Diabetes Research, Duesseldorf (Germany). Inst. for Clinical Diabetology; University Hospital of Tuebingen (Germany). Div. of Endocrinology, Diabetes, Nephrology, Angiology, and Clinical Chemistry; Schraml, C.; Schwenzer, N.F. [University Hospital of Tuebingen (Germany). Dept. of Radiology, Section on Experimental Radiology; University Hospital of Tuebingen (Germany). Dept. of Radiology, Diagnostic and Interventional Radiology; Rietig, R.; Balletshofer, B. [University Hospital of Tuebingen (Germany). Div. of Endocrinology, Diabetes, Nephrology, Angiology, and Clinical Chemistry; Martirosian, P.; Haering, H.U.; Schick, F. [University Hospital of Tuebingen (Germany). Dept. of Radiology, Section on Experimental Radiology; Claussen, C.D. [University Hospital of Tuebingen (Germany). Dept. of Radiology, Diagnostic and Interventional Radiology

    2012-12-15

    Purpose: Though increased thyroid perfusion assessed by colour-coded Doppler ultrasound (CDUS) is characteristic of Graves' disease (GD), sometimes perfusion assessment by CDUS is not possible. In these cases, arterial spin labelling (ASL), a novel magnetic resonance imaging (MRI) technique allowing non-invasive thyroid perfusion quantification, may have additional diagnostic value. We aimed to evaluate the potential of ASL-MRI for assessment of increased blood perfusion in patients with GD compared to CDUS. Materials and Methods: Thyroid perfusion was measured by CDUS (volume flow rate calculated from pulsed wave Doppler signals and vessel diameter) and ASL-MRI at 1.5 T in 7 patients with GD and 10 healthy controls. Results: In patients with GD, average perfusion in both thyroid lobes was markedly increased compared to controls. Both techniques applied for volume related perfusion as well as absolute volume flow in thyroid feeding vessels provided similar results (all p = 0.0008). Using a cut-off value of 22 ml/min for the volume flow rate assessed by CDUS in the four feeding vessels allowed discrimination between patients with GD and controls in all cases. After adjusting thyroid perfusion for the differences in organ volume, both CDUS and ASL revealed also complete discrimination between health and disease. Conclusion: Thyroid perfusion measurement by ASL-MRI reliably discriminate GD from normal thyroid glands. In patients in whom thyroid arteries cannot be depicted by CDUS for technical or anatomical reasons, ASL-MRI may have additional diagnostic value. (orig.)

  3. Exercise, Insulin Absorption Rates, and Artificial Pancreas Control

    Science.gov (United States)

    Frank, Spencer; Hinshaw, Ling; Basu, Rita; Basu, Ananda; Szeri, Andrew J.

    2016-11-01

    Type 1 Diabetes is characterized by an inability of a person to endogenously produce the hormone insulin. Because of this, insulin must be injected - usually subcutaneously. The size of the injected dose and the rate at which the dose reaches the circulatory system have a profound effect on the ability to control glucose excursions, and therefore control of diabetes. However, insulin absorption rates via subcutaneous injection are variable and depend on a number of factors including tissue perfusion, physical activity (vasodilation, increased capillary throughput), and other tissue geometric and physical properties. Exercise may also have a sizeable effect on the rate of insulin absorption, which can potentially lead to dangerous glucose levels. Insulin-dosing algorithms, as implemented in an artificial pancreas controller, should account accurately for absorption rate variability and exercise effects on insulin absorption. The aforementioned factors affecting insulin absorption will be discussed within the context of both fluid mechanics and data driven modeling approaches.

  4. Glycopyrrolate abolishes the exercise-induced increase in cerebral perfusion in humans

    DEFF Research Database (Denmark)

    Seifert, Thomas; Fisher, James P; Young, Colin N

    2010-01-01

    Brain blood vessels contain muscarinic receptors that are important for cerebral blood flow (CBF) regulation, but whether a cholinergic receptor mechanism is involved in the exercise-induced increase in cerebral perfusion or affects cerebral metabolism remains unknown. We evaluated CBF and cerebral......(mean) during ergometer cycling (n = 8). Separate, randomized and counterbalanced trials were performed in control (no drug) conditions and following muscarinic cholinergic receptor blockade by glycopyrrolate. Glycopyrrolate increased resting heart rate from approximately 60 to approximately 110 beats min(-1...... abolished by glycopyrrolate (P important for the exercise-induced increase in cerebral perfusion without affecting the cerebral metabolic rate for oxygen....

  5. Hepatic blood perfusion estimated by dynamic contrast-enhanced computed tomography in pigs

    DEFF Research Database (Denmark)

    Winterdahl, Michael; Sørensen, Michael; Keiding, Inger Susanne

    2012-01-01

    The aim of this study was to determine whether dynamic contrast-enhanced computed tomography (DCE-CT) and the slope method can provide absolute measures of hepatic blood perfusion from the hepatic artery (HA) and portal vein (PV) at experimentally varied blood flow rates.......The aim of this study was to determine whether dynamic contrast-enhanced computed tomography (DCE-CT) and the slope method can provide absolute measures of hepatic blood perfusion from the hepatic artery (HA) and portal vein (PV) at experimentally varied blood flow rates....

  6. The biphasic effect of extracellular glucose concentration on carbachol-induced fluid secretion from mouse submandibular glands.

    Science.gov (United States)

    Terachi, Momomi; Hirono, Chikara; Kitagawa, Michinori; Sugita, Makoto

    2018-06-01

    Cholinergic agonists evoke elevations of the cytoplasmic free-calcium concentration ([Ca 2+ ] i ) to stimulate fluid secretion in salivary glands. Salivary flow rates are significantly reduced in diabetic patients. However, it remains elusive how salivary secretion is impaired in diabetes. Here, we used an ex vivo submandibular gland perfusion technique to characterize the dependency of salivary flow rates on extracellular glucose concentration and activities of glucose transporters expressed in the glands. The cholinergic agonist carbachol (CCh) induced sustained fluid secretion, the rates of which were modulated by the extracellular glucose concentration in a biphasic manner. Both lowering the extracellular glucose concentration to less than 2.5 mM and elevating it to higher than 5 mM resulted in decreased CCh-induced fluid secretion. The CCh-induced salivary flow was suppressed by phlorizin, an inhibitor of the sodium-glucose cotransporter 1 (SGLT1) located basolaterally in submandibular acinar cells, which is altered at the protein expression level in diabetic animal models. Our data suggest that SGLT1-mediated glucose uptake in acinar cells is required to maintain the fluid secretion by sustaining Cl - secretion in real-time. High extracellular glucose levels may suppress the CCh-induced secretion of salivary fluid by altering the activities of ion channels and transporters downstream of [Ca 2+ ] i signals. © 2018 Eur J Oral Sci.

  7. Regional cortical hyper perfusion on perfusion CT during postical motor deficit: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Hye Jin [Dept. of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of)

    2013-08-15

    Postictal neurologic deficit is a well-known complication mimicking the manifestation of a stroke. We present a case of a patient with clinical evidence of Todd's paralysis correlating with reversible postictal parenchymal changes on perfusion CT and magnetic resonance (MR) imaging. In this case, perfusion CT and MR imaging were helpful in the differential diagnosis of stroke-mimicking conditions.

  8. The Groningen hypothermic liver perfusion pump : Functional evaluation of a new machine perfusion system

    NARCIS (Netherlands)

    van der Plaats, A.; Maathuis, M. H. J.; Hart, N. A. 't; Bellekom, A. A.; Hofker, H. S.; van der Houwen, E. B.; Verkerke, G. J.; Leuvenink, H. G. D.; Verdonck, P.; Ploeg, R. J.; Rakhorst, G.

    2006-01-01

    To improve preservation of donor livers, we have developed a portable hypothermic machine perfusion (HMP) system as an alternative for static cold storage. A prototype of the system was built and evaluated on functionality. Evaluation criteria included 24 h of adequate pressure controlled perfusion,

  9. Effects of Steroid Hormones on Sex Differences in Cerebral Perfusion.

    Directory of Open Access Journals (Sweden)

    Carmen Ghisleni

    Full Text Available Sex differences in the brain appear to play an important role in the prevalence and progression of various neuropsychiatric disorders, but to date little is known about the cerebral mechanisms underlying these differences. One widely reported finding is that women demonstrate higher cerebral perfusion than men, but the underlying cause of this difference in perfusion is not known. This study investigated the putative role of steroid hormones such as oestradiol, testosterone, and dehydroepiandrosterone sulphate (DHEAS as underlying factors influencing cerebral perfusion. We acquired arterial spin labelling perfusion images of 36 healthy adult subjects (16 men, 20 women. Analyses on average whole brain perfusion levels included a multiple regression analysis to test for the relative impact of each hormone on the global perfusion. Additionally, voxel-based analyses were performed to investigate the sex difference in regional perfusion as well as the correlations between local perfusion and serum oestradiol, testosterone, and DHEAS concentrations. Our results replicated the known sex difference in perfusion, with women showing significantly higher global and regional perfusion. For the global perfusion, DHEAS was the only significant predictor amongst the steroid hormones, showing a strong negative correlation with cerebral perfusion. The voxel-based analyses revealed modest sex-dependent correlations between local perfusion and testosterone, in addition to a strong modulatory effect of DHEAS in cortical, subcortical, and cerebellar regions. We conclude that DHEAS in particular may play an important role as an underlying factor driving the difference in cerebral perfusion between men and women.

  10. Perfusion MRI in CNS disease: current concepts

    International Nuclear Information System (INIS)

    Essig, M.; Giesel, F.; Le-Huu, M.; Stieltjes, B.; Tengg, H. von; Weber, M.-A.

    2004-01-01

    Today there are several indications for cerebral perfusion MRI. The major indications routinely used in increasing numbers of imaging centers include cerebrovascular disease, tumor imaging and recently psychiatric disorders. Perfusion MRI is based on the injection of a gadolinium chelate and the rapid acquisition of images as the bolus of contrast agent passes through the blood vessels in the brain. The contrast agent causes a signal change; this signal change over time can be analysed to measure cerebral hemodynamics. The quality of brain perfusion studies is very dependent on the contrast agent used: a robust and strong signal decrease with a compact bolus is needed. MultiHance (gadobenate dimeglumine, Gd-BOPTA) is the first of a new class of paramagnetic MR contrast agents with a weak affinity for serum proteins. Due to the interaction of Gd-BOPTA with serum albumin, MultiHance presents with significantly higher T1- and T2-relaxivities enabling a sharper bolus profile. This article reviews the indications of perfusion MRI and the performance of MultiHance in MR perfusion of different diseases. Previous studies using perfusion MRI for a variety of purposes required the use of double dose of contrast agent to achieve a sufficiently large signal drop to enable the acquisition of a clear input function and the calculation of perfusion rCBV and rCBF maps of adequate quality. Recent studies with Multi-Hance suggest that only a single dose of this agent is needed to cause a signal drop of about 30% which is sufficient to allow the calculation of high quality rCBV and rCBF maps. (orig.)

  11. Fluid therapy in small ruminants and camelids.

    Science.gov (United States)

    Jones, Meredyth; Navarre, Christine

    2014-07-01

    Body water, electrolytes, and acid-base balance are important considerations in the evaluation and treatment of small ruminants and camelids with any disease process, with restoration of these a priority as adjunctive therapy. The goals of fluid therapy should be to maintain cardiac output and tissue perfusion, and to correct acid-base and electrolyte abnormalities. Hypoglycemia, hyperkalemia, and acidosis are the most life-threatening abnormalities, and require most immediate correction. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Fluids engineering

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Fluids engineering has played an important role in many applications, from ancient flood control to the design of high-speed compact turbomachinery. New applications of fluids engineering, such as in high-technology materials processing, biotechnology, and advanced combustion systems, have kept up unwaining interest in the subject. More accurate and sophisticated computational and measurement techniques are also constantly being developed and refined. On a more fundamental level, nonlinear dynamics and chaotic behavior of fluid flow are no longer an intellectual curiosity and fluid engineers are increasingly interested in finding practical applications for these emerging sciences. Applications of fluid technology to new areas, as well as the need to improve the design and to enhance the flexibility and reliability of flow-related machines and devices will continue to spur interest in fluids engineering. The objectives of the present seminar were: to exchange current information on arts, science, and technology of fluids engineering; to promote scientific cooperation between the fluids engineering communities of both nations, and to provide an opportunity for the participants and their colleagues to explore possible joint research programs in topics of high priority and mutual interest to both countries. The Seminar provided an excellent forum for reviewing the current state and future needs of fluids engineering for the two nations. With the Seminar ear-marking the first formal scientific exchange between Korea and the United States in the area of fluids engineering, the scope was deliberately left broad and general

  13. [An automatic system controlled by microcontroller for carotid sinus perfusion].

    Science.gov (United States)

    Yi, X L; Wang, M Y; Fan, Z Z; He, R R

    2001-08-01

    To establish a new method for controlling automatically the carotid perfusion pressure. A cheap practical automatic perfusion unit based on AT89C2051 micro controller was designed. The unit, LDB-M perfusion pump and the carotid sinus of an animal constituted an automatic perfusion system. This system was able to provide ramp and stepwise updown perfusion pattern and has been used in the research of baroreflex. It can insure the precision and reproducibility of perfusion pressure curve, and improve the technical level in corresponding medical field.

  14. Inhibition of gluconeogenesis in the perfusing liver of irradiated rats

    International Nuclear Information System (INIS)

    Borovikova, G.V.; Dokshina, G.A.; Ermakova, G.N.; Mashkova, N.Yu.

    1981-01-01

    It was shown on the perfusing liver taken from rats on the 1st and 3d days after irradiation in a dose of 18.06x10 -2 C/kg that insulin (400 μunits/ml) and taurine (40 mg%) exerted an inhibiting action on the rate of gluconeogenesi.s and transamination, catalyzed by alanine aminoferase and aspartate aminoferase, in a soluble fraction of the irradiated rat liver. The gluconeogenic capacity and the reactivity of the isolated organ were shown to decrease on the 3d day after irradiation [ru

  15. Myocardial perfusion imaging with dual energy CT

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Kwang Nam [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, SMG-SNU Boramae Medical Center, Seoul (Korea, Republic of); De Cecco, Carlo N. [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Caruso, Damiano [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiological Sciences, Oncology and Pathology, University of Rome “Sapienza”, Rome (Italy); Tesche, Christian [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich (Germany); Spandorfer, Adam; Varga-Szemes, Akos [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States)

    2016-10-15

    Highlights: • Stress dual-energy sCTMPI offers the possibility to directly detect the presence of myocardial perfusion defects. • Stress dual-energy sCTMPI allows differentiating between reversible and fixed myocardial perfusion defects. • The combination of coronary CT angiography and dual-energy sCTMPI can improve the ability of CT to detect hemodynamically relevant coronary artery disease. - Abstract: Dual-energy CT (DECT) enables simultaneous use of two different tube voltages, thus different x-ray absorption characteristics are acquired in the same anatomic location with two different X-ray spectra. The various DECT techniques allow material decomposition and mapping of the iodine distribution within the myocardium. Static dual-energy myocardial perfusion imaging (sCTMPI) using pharmacological stress agents demonstrate myocardial ischemia by single snapshot images of myocardial iodine distribution. sCTMPI gives incremental values to coronary artery stenosis detected on coronary CT angiography (CCTA) by showing consequent reversible or fixed myocardial perfusion defects. The comprehensive acquisition of CCTA and sCTMPI offers extensive morphological and functional evaluation of coronary artery disease. Recent studies have revealed that dual-energy sCTMPI shows promising diagnostic accuracy for the detection of hemodynamically significant coronary artery disease compared to single-photon emission computed tomography, invasive coronary angiography, and cardiac MRI. The aim of this review is to present currently available DECT techniques for static myocardial perfusion imaging and recent clinical applications and ongoing investigations.

  16. TH-CD-206-01: Expectation-Maximization Algorithm-Based Tissue Mixture Quantification for Perfusion MRI

    Energy Technology Data Exchange (ETDEWEB)

    Han, H; Xing, L [Stanford University, Palo Alto, CA (United States); Liang, Z [Stony Brook University, Stony Brook, NY (United States); Li, L [City University of New York College of Staten Island, Staten Island, NY (United States)

    2016-06-15

    Purpose: To investigate the feasibility of estimating the tissue mixture perfusions and quantifying cerebral blood flow change in arterial spin labeled (ASL) perfusion MR images. Methods: The proposed perfusion MR image analysis framework consists of 5 steps: (1) Inhomogeneity correction was performed on the T1- and T2-weighted images, which are available for each studied perfusion MR dataset. (2) We used the publicly available FSL toolbox to strip off the non-brain structures from the T1- and T2-weighted MR images. (3) We applied a multi-spectral tissue-mixture segmentation algorithm on both T1- and T2-structural MR images to roughly estimate the fraction of each tissue type - white matter, grey matter and cerebral spinal fluid inside each image voxel. (4) The distributions of the three tissue types or tissue mixture across the structural image array are down-sampled and mapped onto the ASL voxel array via a co-registration operation. (5) The presented 4-dimensional expectation-maximization (4D-EM) algorithm takes the down-sampled three tissue type distributions on perfusion image data to generate the perfusion mean, variance and percentage images for each tissue type of interest. Results: Experimental results on three volunteer datasets demonstrated that the multi-spectral tissue-mixture segmentation algorithm was effective to initialize tissue mixtures from T1- and T2-weighted MR images. Compared with the conventional ASL image processing toolbox, the proposed 4D-EM algorithm not only generated comparable perfusion mean images, but also produced perfusion variance and percentage images, which the ASL toolbox cannot obtain. It is observed that the perfusion contribution percentages may not be the same as the corresponding tissue mixture volume fractions estimated in the structural images. Conclusion: A specific application to brain ASL images showed that the presented perfusion image analysis method is promising for detecting subtle changes in tissue perfusions

  17. TH-CD-206-01: Expectation-Maximization Algorithm-Based Tissue Mixture Quantification for Perfusion MRI

    International Nuclear Information System (INIS)

    Han, H; Xing, L; Liang, Z; Li, L

    2016-01-01

    Purpose: To investigate the feasibility of estimating the tissue mixture perfusions and quantifying cerebral blood flow change in arterial spin labeled (ASL) perfusion MR images. Methods: The proposed perfusion MR image analysis framework consists of 5 steps: (1) Inhomogeneity correction was performed on the T1- and T2-weighted images, which are available for each studied perfusion MR dataset. (2) We used the publicly available FSL toolbox to strip off the non-brain structures from the T1- and T2-weighted MR images. (3) We applied a multi-spectral tissue-mixture segmentation algorithm on both T1- and T2-structural MR images to roughly estimate the fraction of each tissue type - white matter, grey matter and cerebral spinal fluid inside each image voxel. (4) The distributions of the three tissue types or tissue mixture across the structural image array are down-sampled and mapped onto the ASL voxel array via a co-registration operation. (5) The presented 4-dimensional expectation-maximization (4D-EM) algorithm takes the down-sampled three tissue type distributions on perfusion image data to generate the perfusion mean, variance and percentage images for each tissue type of interest. Results: Experimental results on three volunteer datasets demonstrated that the multi-spectral tissue-mixture segmentation algorithm was effective to initialize tissue mixtures from T1- and T2-weighted MR images. Compared with the conventional ASL image processing toolbox, the proposed 4D-EM algorithm not only generated comparable perfusion mean images, but also produced perfusion variance and percentage images, which the ASL toolbox cannot obtain. It is observed that the perfusion contribution percentages may not be the same as the corresponding tissue mixture volume fractions estimated in the structural images. Conclusion: A specific application to brain ASL images showed that the presented perfusion image analysis method is promising for detecting subtle changes in tissue perfusions

  18. Standardized perfusion value of the esophageal carcinoma and its correlation with quantitative CT perfusion parameter values

    Energy Technology Data Exchange (ETDEWEB)

    Djuric-Stefanovic, A., E-mail: avstefan@eunet.rs [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Saranovic, Dj., E-mail: crvzve4@gmail.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Sobic-Saranovic, D., E-mail: dsobic2@gmail.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Center of Nuclear Medicine, Clinical Center of Serbia, Belgrade (Serbia); Masulovic, D., E-mail: draganmasulovic@yahoo.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Artiko, V., E-mail: veraart@beotel.rs [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Center of Nuclear Medicine, Clinical Center of Serbia, Belgrade (Serbia)

    2015-03-15

    Purpose: Standardized perfusion value (SPV) is a universal indicator of tissue perfusion, normalized to the whole-body perfusion, which was proposed to simplify, unify and allow the interchangeability among the perfusion measurements and comparison between the tumor perfusion and metabolism. The aims of our study were to assess the standardized perfusion value (SPV) of the esophageal carcinoma, and its correlation with quantitative CT perfusion measurements: blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) of the same tumor volume samples, which were obtained by deconvolution-based CT perfusion analysis. Methods: Forty CT perfusion studies of the esophageal cancer were analyzed, using the commercial deconvolution-based CT perfusion software (Perfusion 3.0, GE Healthcare). The SPV of the esophageal tumor and neighboring skeletal muscle were correlated with the corresponding mean tumor and muscle quantitative CT perfusion parameter values, using Spearman's rank correlation coefficient (r{sub S}). Results: Median SPV of the esophageal carcinoma (7.1; range: 2.8–13.4) significantly differed from the SPV of the skeletal muscle (median: 1.0; range: 0.4–2.4), (Z = −5.511, p < 0.001). The cut-off value of the SPV of 2.5 enabled discrimination of esophageal cancer from the skeletal muscle with sensitivity and specificity of 100%. SPV of the esophageal carcinoma significantly correlated with corresponding tumor BF (r{sub S} = 0.484, p = 0.002), BV (r{sub S} = 0.637, p < 0.001) and PS (r{sub S} = 0.432, p = 0.005), and SPV of the skeletal muscle significantly correlated with corresponding muscle BF (r{sub S} = 0.573, p < 0.001), BV (r{sub S} = 0.849, p < 0.001) and PS (r{sub S} = 0.761, p < 0.001). Conclusions: We presented a database of the SPV for the esophageal cancer and proved that SPV of the esophageal neoplasm significantly differs from the SPV of the skeletal muscle, which represented a sample of healthy

  19. Laws of physics help explain capillary non-perfusion in diabetic retinopathy.

    Science.gov (United States)

    Stefánsson, E; Chan, Y K; Bek, T; Hardarson, S H; Wong, D; Wilson, D I

    2018-02-01

    The purpose is to use laws of physics to elucidate the mechanisms behind capillary non-perfusion in diabetic retinopathy. In diabetic retinopathy, loss of pericytes weakens capillary walls and the vessel dilates. A dilated capillary has reduced resistance to flow, therefore increased flow in that vessel and decreased in adjoining capillaries. A preferential shunt vessel is thus formed from the dilated capillary and the adjacent capillaries become non-perfused. We apply the laws of Laplace and Hagen-Poiseuille to better understand the phenomena that lead to capillary non-perfusion. These laws of physics can give a foundation for physical or mathematical models to further elucidate this field of study. The law of Laplace predicts that a weaker vessel wall will dilate, assuming constant transmural pressure. The Hagen-Poiseuille equation for flow and the Ostwald-de Waele relationship for viscosity predict that a dilated vessel will receive a higher portion of the fluid flow than the adjoining capillaries. Viscosity will decrease in the dilated vessel, furthering the imbalance and resulting in a patch of non-perfused capillaries next to the dilated 'preferential' shunt vessel. Physical principles support or inspire novel hypotheses to explain poorly understood phenomena in ophthalmology. This thesis of pericyte death and capillary remodelling, which was first proposed by Cogan and Kuwabara, already agrees with histological and angiographical observations in diabetic retinopathy. We have shown that it is also supported by classical laws of physics.

  20. Buffer fluid

    Energy Technology Data Exchange (ETDEWEB)

    Mirzadzhanzade, A Kh; Dedusanko, G Ya; Dinaburg, L S; Markov, Yu M; Rasizade, Ya N; Rozov, V N; Sherstnev, N M

    1979-08-30

    A drilling fluid is suggested for separating the drilling and plugging fluids which contains as the base increased solution of polyacrylamide and additive. In order to increase the viscoelastic properties of the liquid with simultaneous decrease in the periods of its fabrication, the solution contains as an additive dry bentonite clay. In cases of the use of a buffer fluid under conditions of negative temperatures, it is necessary to add to it table salt or ethylene glycol.

  1. Low pulmonary artery flush perfusion pressure combined with high positive end-expiratory pressure reduces oedema formation in isolated porcine lungs

    International Nuclear Information System (INIS)

    Schumann, Stefan; Schließmann, Stephan J; Wagner, Giskard; Goebel, Ulrich; Priebe, Hans-Joachim; Guttmann, Josef; Kirschbaum, Andreas

    2010-01-01

    Flush perfusion of the pulmonary artery with organ protection solution is a standard procedure before lung explantation. However, rapid flush perfusion may cause pulmonary oedema which is deleterious in the lung transplantation setting. In this study we tested the hypotheses that high pulmonary perfusion pressure contributes to the development of pulmonary oedema and positive end-expiratory pressure (PEEP) counteracts oedema formation. We expected oedema formation to increase weight and decrease compliance of the lungs on the basis of a decrease in alveolar volume as fluid replaces alveolar air spaces. The pulmonary artery of 28 isolated porcine lungs was perfused with a low-potassium dextrane solution at low (mean 27 mmHg) or high (mean 40 mmHg) pulmonary artery pressure (PAP) during mechanical ventilation at low (4 cmH 2 O) or high (8 cmH 2 O) PEEP, respectively. Following perfusion and storage, relative increases in lung weight were smaller (p < 0.05) during perfusion at low PAP (62 ± 32% and 42 ± 26%, respectively) compared to perfusion at high PAP (133 ± 54% and 87 ± 30%, respectively). Compared to all other PAP–PEEP combinations, increases in lung weight were smallest (44 ± 9% and 27 ± 12%, respectively), nonlinear intratidal lung compliance was largest (46% and 17% respectively, both p < 0.05) and lung histology showed least infiltration of mononuclear cells in the alveolar septa, and least alveolar destruction during the combination of low perfusion pressure and high PEEP. The findings suggest that oedema formation during pulmonary artery flush perfusion in isolated and ventilated lungs can be reduced by choosing low perfusion pressure and high PEEP. PAP–PEEP titration to minimize pulmonary oedema should be based on lung mechanics and PAP monitoring

  2. Correlation of semiquantitative analysis of the distribution of pulmonary perfusion with pulmonary function in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    Uchida, Kou; Nakayama, Hiroyuki; Yamagami, Ikue; Takahashi, Hideki; Takano, Masaaki.

    1997-01-01

    We carried out ventilation-perfusion scintigraphy and pulmonary function tests in 56 patients with chronic obstructive pulmonary disease (COPD) and 19 healthy volunteers. We used 99m Tc-macroaggregated albumin for the perfusion scintigraphy and 133 Xe gas for the ventilation scintigraphy. The lung volume image was created by computerized summation of the radioactivity in the rebreathing phase. Regions of interest (ROIs) were set automatically on lung volume image, which included each whole lung, and on perfusion image, including areas with relatively high radioactivity, with cut-off levels of 50%, 70%, and 90%. The number of pixels in each ROI was used as an index of lung volume (L) or perfusion (P). Perfusion per unit of lung volume (P/L) was also used as an index of perfusion. P70 and P70/L showed the better correlations than the other parameters, including significant correlations with vital capacity, FEV 1.0 , peak flow rate, RV/TLC, diffusing capacity and arterial oxygen partial pressure. The significant difference in P70 and P70/L between patients with hypoxemia and those without hypoxemia suggested that P70 and P70/L are useful indicators of the severity of COPD. We conclude that semiquantified values of pulmonary perfusion scintigraphy are significantly correlated with pulmonary function and the severity of COPD. (author)

  3. [Lung perfusion studies after percutaneous closure of patent ductus arteriosus using the Amplatzer Duct Occluder in children].

    Science.gov (United States)

    Parra-Bravo, José Rafael; Apolonio-Martínez, Adriana; Estrada-Loza, María de Jesús; Beirana-Palencia, Luisa Gracia; Ramírez-Portillo, César Iván

    2015-01-01

    The closure of patent ductus arteriosus with multiple devices has been associated with a reduction in lung perfusion. We evaluated the pulmonary perfusion after percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder device using perfusion lung scan. Thirty patients underwent successful percutaneous patent ductus arteriosus occlusions using the Amplatzer Duct Occluder device were included in this study. Lung perfusion scans were preformed 6 months after the procedure. Peak flow velocities and protrusion of the device were analyzed by Doppler echocardiography. A left lung perfusionductus arteriosus and the minimum and maximum diameter/length of the ductus arteriosus ratio were statistically significant in patients with abnormalities of lung perfusion. It was observed protrusion the device in 6 patients with a higher maximum flow rate in the left pulmonary artery. The left lung perfusion may be compromised after percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder. The increased flow velocity in the origin of the left pulmonary artery can be a poor indicator of reduction in pulmonary perfusion and can occur in the absence of protrusion of the device. Copyright © 2014 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

  4. Impact of CT perfusion imaging on the assessment of peripheral chronic pulmonary thromboembolism: clinical experience in 62 patients

    Energy Technology Data Exchange (ETDEWEB)

    Le Faivre, Julien; Khung, Suonita; Faivre, Jean-Baptiste; Remy, Jacques; Remy-Jardin, Martine [University of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Duhamel, Alain [University of Lille, Department of Biostatistics, Lille (France); Lamblin, Nicolas [University of Lille, Department of Cardiology, Cardiology Hospital, Lille (France)

    2016-11-15

    To evaluate the impact of CT perfusion imaging on the detection of peripheral chronic pulmonary embolisms (CPE). 62 patients underwent a dual-energy chest CT angiographic examination with (a) reconstruction of diagnostic and perfusion images; (b) enabling depiction of vascular features of peripheral CPE on diagnostic images and perfusion defects (20 segments/patient; total: 1240 segments examined). The interpretation of diagnostic images was of two types: (a) standard (i.e., based on cross-sectional images alone) or (b) detailed (i.e., based on cross-sectional images and MIPs). The segment-based analysis showed (a) 1179 segments analyzable on both imaging modalities and 61 segments rated as nonanalyzable on perfusion images; (b) the percentage of diseased segments was increased by 7.2 % when perfusion imaging was compared to the detailed reading of diagnostic images, and by 26.6 % when compared to the standard reading of images. At a patient level, the extent of peripheral CPE was higher on perfusion imaging, with a greater impact when compared to the standard reading of diagnostic images (number of patients with a greater number of diseased segments: n = 45; 72.6 % of the study population). Perfusion imaging allows recognition of a greater extent of peripheral CPE compared to diagnostic imaging. (orig.)

  5. Brain perfusion correlates of cognitive and nigrostriatal functions in de novo Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Nobili, Flavio; Arnaldi, Dario; Campus, Claudio; Ferrara, Michela; Brugnolo, Andrea; Dessi, Barbara; Girtler, Nicola; Rodriguez, Guido [University of Genoa, Clinical Neurophysiology, Department of Neurosciences, Ophthalmology and Genetics, Genoa (Italy); De Carli, Fabrizio [National Research Council, Institute of Molecular Bioimaging and Physiology, Genoa (Italy); Morbelli, Silvia; Sambuceti, Gianmario [University of Genoa, Nuclear Medicine, Department of Internal Medicine, Genoa (Italy); Abruzzese, Giovanni [University Hospital San. Martino, Clinical Neurology, Department of Neurosciences, Ophthalmology and Genetics, Genoa (Italy)

    2011-12-15

    Subtle cognitive impairment is recognized in the first stages of Parkinson's disease (PD), including executive, memory and visuospatial dysfunction, but its pathophysiological basis is still debated. Twenty-six consecutive, drug-naive, de novo PD patients underwent an extended neuropsychological battery, dopamine transporter (DAT) and brain perfusion single photon emission computed tomography (SPECT). We previously reported that nigrocaudate impairment correlates with executive functions, and nigroputaminal impairment with visuospatial abilities. Here perfusion SPECT was first compared between the PD group and age-matched controls (CTR). Then, perfusion SPECT was correlated with both DAT SPECT and four neuropsychological factors by means of voxel-based analysis (SPM8) with a height threshold of p < 0.005 at peak level and p < 0.05 false discovery rate-corrected at cluster level. Both perfusion and DAT SPECT images were flipped in order to have the more affected hemisphere (MAH), defined clinically, on the same side. Significant hypoperfusion was found in an occipital area of the MAH in PD patients as compared to CTR. Executive functions directly correlated with brain perfusion in bilateral posterior cingulate cortex and precuneus in the less affected hemisphere (LAH), while verbal memory directly correlated with perfusion in the precuneus, inferior parietal lobule and superior temporal gyrus in the LAH. Furthermore, positive correlation was highlighted between nigrocaudate and nigroputaminal impairment and brain perfusion in the precuneus, posterior cingulate and parahippocampal gyri of the LAH. These data support the evidence showing an early involvement of the cholinergic system in the early cognitive dysfunction and point to a more relevant role of parietal lobes and posterior cingulate in executive functions in PD. (orig.)

  6. Brain perfusion correlates of cognitive and nigrostriatal functions in de novo Parkinson's disease

    International Nuclear Information System (INIS)

    Nobili, Flavio; Arnaldi, Dario; Campus, Claudio; Ferrara, Michela; Brugnolo, Andrea; Dessi, Barbara; Girtler, Nicola; Rodriguez, Guido; De Carli, Fabrizio; Morbelli, Silvia; Sambuceti, Gianmario; Abruzzese, Giovanni

    2011-01-01

    Subtle cognitive impairment is recognized in the first stages of Parkinson's disease (PD), including executive, memory and visuospatial dysfunction, but its pathophysiological basis is still debated. Twenty-six consecutive, drug-naive, de novo PD patients underwent an extended neuropsychological battery, dopamine transporter (DAT) and brain perfusion single photon emission computed tomography (SPECT). We previously reported that nigrocaudate impairment correlates with executive functions, and nigroputaminal impairment with visuospatial abilities. Here perfusion SPECT was first compared between the PD group and age-matched controls (CTR). Then, perfusion SPECT was correlated with both DAT SPECT and four neuropsychological factors by means of voxel-based analysis (SPM8) with a height threshold of p < 0.005 at peak level and p < 0.05 false discovery rate-corrected at cluster level. Both perfusion and DAT SPECT images were flipped in order to have the more affected hemisphere (MAH), defined clinically, on the same side. Significant hypoperfusion was found in an occipital area of the MAH in PD patients as compared to CTR. Executive functions directly correlated with brain perfusion in bilateral posterior cingulate cortex and precuneus in the less affected hemisphere (LAH), while verbal memory directly correlated with perfusion in the precuneus, inferior parietal lobule and superior temporal gyrus in the LAH. Furthermore, positive correlation was highlighted between nigrocaudate and nigroputaminal impairment and brain perfusion in the precuneus, posterior cingulate and parahippocampal gyri of the LAH. These data support the evidence showing an early involvement of the cholinergic system in the early cognitive dysfunction and point to a more relevant role of parietal lobes and posterior cingulate in executive functions in PD. (orig.)

  7. Fed-batch and perfusion culture processes: economic, environmental, and operational feasibility under uncertainty.

    Science.gov (United States)

    Pollock, James; Ho, Sa V; Farid, Suzanne S

    2013-01-01

    This article evaluates the current and future potential of batch and continuous cell culture technologies via a case study based on the commercial manufacture of monoclonal antibodies. The case study compares fed-batch culture to two perfusion technologies: spin-filter perfusion and an emerging perfusion technology utilizing alternating tangential flow (ATF) perfusion. The operational, economic, and environmental feasibility of whole bioprocesses based on these systems was evaluated using a prototype dynamic decision-support tool built at UCL encompassing process economics, discrete-event simulation and uncertainty analysis, and combined with a multi-attribute decision-making technique so as to enable a holistic assessment. The strategies were compared across a range of scales and titres so as to visualize how their ranking changes in different industry scenarios. The deterministic analysis indicated that the ATF perfusion strategy has the potential to offer cost of goods savings of 20% when compared to conventional fed-batch manufacturing processes when a fivefold increase in maximum viable cell densities was assumed. Savings were also seen when the ATF cell density dropped to a threefold increase over the fed-batch strategy for most combinations of titres and production scales. In contrast, the fed-batch strategy performed better in terms of environmental sustainability with a lower water and consumable usage profile. The impact of uncertainty and failure rates on the feasibility of the strategies was explored using Monte Carlo simulation. The risk analysis results demonstrated the enhanced robustness of the fed-batch process but also highlighted that the ATF process was still the most cost-effective option even under uncertainty. The multi-attribute decision-making analysis provided insight into the limited use of spin-filter perfusion strategies in industry. The resulting sensitivity spider plots enabled identification of the critical ratio of weightings of

  8. Dynamic perfusion patterns in temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Dupont, Patrick; Paesschen, Wim van; Zaknun, John J.; Maes, Alex; Tepmongkol, Supatporn; Locharernkul, Chaichon; Vasquez, Silvia; Carpintiero, Silvina; Bal, C.S.; Dondi, Maurizio

    2009-01-01

    To investigate dynamic ictal perfusion changes during temporal lobe epilepsy (TLE). We investigated 37 patients with TLE by ictal and interictal SPECT. All ictal injections were performed within 60 s of seizure onset. Statistical parametric mapping was used to analyse brain perfusion changes and temporal relationships with injection time and seizure duration as covariates. The analysis revealed significant ictal hyperperfusion in the ipsilateral temporal lobe extending to subcortical regions. Hypoperfusion was observed in large extratemporal areas. There were also significant dynamic changes in several extratemporal regions: ipsilateral orbitofrontal and bilateral superior frontal gyri and the contralateral cerebellum and ipsilateral striatum. The study demonstrated early dynamic perfusion changes in extratemporal regions probably involved in both propagation of epileptic activity and initiation of inhibitory mechanisms. (orig.)

  9. Dynamic perfusion patterns in temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, Patrick; Paesschen, Wim van [KU Leuven/UZ Gasthuisberg, Nuclear Medicine, Medical Imaging Center and Neurology, Leuven (Belgium); Zaknun, John J. [International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, PO BOX 200, Vienna (Austria); University Hospital of Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Maes, Alex [KU Leuven/UZ Gasthuisberg, Nuclear Medicine, Medical Imaging Center and Neurology, Leuven (Belgium); AZ Groeninge, Nuclear Medicine, Kortrijk (Belgium); Tepmongkol, Supatporn; Locharernkul, Chaichon [Chulalongkorn University, Nuclear Medicine and Neurology, Bangkok (Thailand); Vasquez, Silvia; Carpintiero, Silvina [Fleni Instituto de Investigaciones Neurologicas, Nuclear Medicine, Buenos Aires (Argentina); Bal, C.S. [All India Institute of Medical Sciences, Nuclear Medicine, New Delhi (India); Dondi, Maurizio [International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, PO BOX 200, Vienna (Austria); Ospedale Maggiore, Nuclear Medicine, Bologna (Italy)

    2009-05-15

    To investigate dynamic ictal perfusion changes during temporal lobe epilepsy (TLE). We investigated 37 patients with TLE by ictal and interictal SPECT. All ictal injections were performed within 60 s of seizure onset. Statistical parametric mapping was used to analyse brain perfusion changes and temporal relationships with injection time and seizure duration as covariates. The analysis revealed significant ictal hyperperfusion in the ipsilateral temporal lobe extending to subcortical regions. Hypoperfusion was observed in large extratemporal areas. There were also significant dynamic changes in several extratemporal regions: ipsilateral orbitofrontal and bilateral superior frontal gyri and the contralateral cerebellum and ipsilateral striatum. The study demonstrated early dynamic perfusion changes in extratemporal regions probably involved in both propagation of epileptic activity and initiation of inhibitory mechanisms. (orig.)

  10. Cardiac tissue engineering using perfusion bioreactor systems

    Science.gov (United States)

    Radisic, Milica; Marsano, Anna; Maidhof, Robert; Wang, Yadong; Vunjak-Novakovic, Gordana

    2009-01-01

    This protocol describes tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cell populations on porous scaffolds (in some cases with an array of channels) and bioreactors with perfusion of culture medium (in some cases supplemented with an oxygen carrier). The overall approach is ‘biomimetic’ in nature as it tends to provide in vivo-like oxygen supply to cultured cells and thereby overcome inherent limitations of diffusional transport in conventional culture systems. In order to mimic the capillary network, cells are cultured on channeled elastomer scaffolds that are perfused with culture medium that can contain oxygen carriers. The overall protocol takes 2–4 weeks, including assembly of the perfusion systems, preparation of scaffolds, cell seeding and cultivation, and on-line and end-point assessment methods. This model is well suited for a wide range of cardiac tissue engineering applications, including the use of human stem cells, and high-fidelity models for biological research. PMID:18388955

  11. Cerebral perfusion imaging in HIV positive patients

    International Nuclear Information System (INIS)

    Kundley, Kshama; Chowdhury, D.; Lele, V.R.; Lele, R.D.

    1998-01-01

    Full text: Twelve human immunodeficiency virus (HIV) positive patients were studied by SPECT cerebral perfusion imaging 1 hour post injection of 15 mCi of 99m Tc-ECD under ideal conditions with a triple head gamma camera (Prism 3000 X P LEUHR), fanbeam collimators followed by Folstein Mini Mental Status Examination (FMMSE) and AIDS dementia complex (ADC) staging on the same day. All 12 patients were male, in the age range of 23-45 y (mean 31 y). The infected status was diagnosed by ELISA (10 patients) or Western blot (5 patients). The interval between diagnosis and imaging ranged from 1 month - 35 months (mean 15.3 months). Two patients were alcoholic and 2 were smokers. None of them had CNS disorder clinically. ADC staging and FMMSE could be performed in 4 patients. Two patients were normal (stage 0) and 2 were subclinical (stage 0.5) on ADC staging. FMMSE revealed normal or near normal status (mean score 35; maximum score 36). Cerebral perfusion images were interpreted simultaneously by 3 observers blind towards history and examination using semi-quantitative and quantitative methods by consensus. It revealed multiple areas of hypoperfusion, viz. temporal (11 patients (91 %), parietal 10 patients (83%), frontal 9 patients (75%, pre and post central gyrus 7 patients (58%), occipital 6 patients (50%) cingulate gyrus and cerebellum 5 patients (41%) and thalamic in 2 patients (16%). Hyper perfusion in caudate nuclei was noted in 10 patients (83%). The study reveals presence of multiple perfusion abnormalities on cerebral perfusion imaging in HIV positive patients who have normal/near normal mental status suggesting precedence of perfusion abnormality over clinically apparent mental deficit

  12. Abnormal perfusion on myocardial perfusion SPECT in patients with Wolff-Parkinson-White syndrome

    International Nuclear Information System (INIS)

    Kang, Do Young; Cha, Kwang Soo; Han, Seung Ho; Park, Tae Ho; Kim, Moo Hyun; Kim, Young Dae

    2005-01-01

    Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on myocardial perfusion SPECT and location of AP in patients with WPW (Wolff-Parkison-White) syndrome. Adenosine Tc-99m MIBI or Tl-201 myocardial perfusion SPECT was performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECT with Fitzpatrick's algorithm of electrophysiologic study and radiofrequency catheter ablation. Patients had atypical chest discomfort or no symptom. Risk of coronary artery disease (CAD) was below 0.1 in 11 patients using the nomogram to estimate the probability of CAD. Coronary angiography was performed in 4 patients(mid-LAD 50% in one, normal in others). In 4 patients, AP localization was done by electrophysiologic study and radiofrequency catheter ablation (RFCA). Small to large extent (11.0 ± 8.5%, range:3 ∼ 35%) and mild to moderate severity (-71 ± 42.7%, range:-217 ∼ -39%) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patients with right free wall (right lateral) AP showed normal. PD locations were variable following the location of AP. One patient with left lateral wall AP was followed 6 weeks after RFCA and showed significantly decreased PD on SPECT with successful ablation. Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. Abnormal perfusion defect showed in most of all patients, but if did not seem to be correlated specifically with location of accessory pathway and coronary artery disease. Therefore myocardial perfusion SPECT should be interpreted carefully in patients with WPW syndrome

  13. Abnormal perfusion on myocardial perfusion SPECT in patients with Wolff-Parkinson-White syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Do Young; Cha, Kwang Soo; Han, Seung Ho; Park, Tae Ho; Kim, Moo Hyun; Kim, Young Dae [Donga University College of Medicine, Busan (Korea, Republic of)

    2005-02-15

    Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on myocardial perfusion SPECT and location of AP in patients with WPW (Wolff-Parkison-White) syndrome. Adenosine Tc-99m MIBI or Tl-201 myocardial perfusion SPECT was performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECT with Fitzpatrick's algorithm of electrophysiologic study and radiofrequency catheter ablation. Patients had atypical chest discomfort or no symptom. Risk of coronary artery disease (CAD) was below 0.1 in 11 patients using the nomogram to estimate the probability of CAD. Coronary angiography was performed in 4 patients(mid-LAD 50% in one, normal in others). In 4 patients, AP localization was done by electrophysiologic study and radiofrequency catheter ablation (RFCA). Small to large extent (11.0 {+-} 8.5%, range:3 {approx} 35%) and mild to moderate severity (-71 {+-} 42.7%, range:-217 {approx} -39%) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patients with right free wall (right lateral) AP showed normal. PD locations were variable following the location of AP. One patient with left lateral wall AP was followed 6 weeks after RFCA and showed significantly decreased PD on SPECT with successful ablation. Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. Abnormal perfusion defect showed in most of all patients, but if did not seem to be correlated specifically with location of accessory pathway and coronary artery disease. Therefore myocardial perfusion SPECT should be interpreted carefully in patients with WPW syndrome.

  14. Protective effect of active perfusion in porcine models of acute myocardial ischemia

    Science.gov (United States)

    Feng, Zanxiang; Mao, Zhifu; Dong, Shengjun; Liu, Baohui

    2016-01-01

    Mortality rates associated with off-pump coronary artery bypass (CAB) are relatively high, as the majority of patients requiring CAB are at a high risk for cardiac events. The present study aimed to establish porcine models of acute myocardial ischemia, and evaluate the protective role of shunt and active perfusion. A total of 30 pigs were randomly assigned to five groups, as follows: i) Sham (control); ii) A1 (shunt; stenosis rate, 55%); iii) A2 (shunt; stenosis rate, 75%); iv) B1 (active perfusion; stenosis rate, 55%); and v) B2 (active perfusion; stenosis rate, 75%) groups. Aortic pressure (P0), left anterior descending coronary pressure (P1), and coronary effective perfusion pressure (P1/P0) were measured. The expression levels of tumor necrosis factor-α (TNF-α), cardiac troponin (cTnI), creatine kinase-myocardial band (CK-MB), interleukin (IL)-6, IL-10, B-cell lymphoma 2 (Bcl-2), and caspase-3 were detected using enzyme-linked immunosorbent assay or western blotting. The myocardial apoptosis rate was determined using the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Ischemia models with stenosis rates of 55 and 75% were successfully constructed following suturing of the descending artery. Compared with the control, the 55 and 75% stenosis groups demonstrated significantly decreased P1/P0, increased expression levels of TNF-α, cTnI, CK-MB, IL-6, IL-10 and caspase-3, an increased rate of myocardial apoptosis, and a decreased expression level of anti-apoptotic protein, Bcl-2. At 30 min following successful establishment of the model (ST segment elevation to 1 mm), group B demonstrated significantly increased P1/P0, decreased expression levels of TNF-α, cTnI, CK-MB, IL-6, IL-10 and caspase-3, a decreased rate of myocardial apoptosis, and an increased expression level of anti-apoptotic protein, Bcl-2. Furthermore, the current study indicated that active perfusion was more efficacious in maintaining myocardial perfusion and alleviating

  15. Changes in myocardial perfusion due to physical exercise in patients with stable coronary artery disease

    International Nuclear Information System (INIS)

    Kendziorra, Kai; Foerster, Marcus; Sabri, Osama; Kluge, Regine; Walther, Claudia; Moebius-Winkler, Sven; Conradi, Katrin; Schuler, Gerhard; Hambrecht, Rainer

    2005-01-01

    Percutaneous transluminal coronary angioplasty (PTCA) is one of the main therapy options for patients with coronary artery disease (CAD), resulting in an improvement in myocardial perfusion and exercise capacity. Nevertheless, studies have also demonstrated a positive effect of regular exercise training on myocardial perfusion and maximum exercise capacity. The aim of this study was to evaluate changes in myocardial stress perfusion after 1 year of exercise training in comparison with the effects of PTCA in patients with CAD. In 66 male patients with angiographically confirmed significant coronary artery stenosis in one target vessel, myocardial perfusion scintigraphy was performed at baseline and 12 months after randomisation into either a physical exercise group or a PTCA group. Circumferential count rate profiles in 16 wall segments were classified according to their relative count rate and localisation within or outside the area supplied by the stenosed vessel. Ischaemic segments showed a significant improvement in myocardial count rate within the target area after 12 months in both the PTCA and the training group (PTCA group: from 76.8±4.9% to 86.6±10.9%, p=0.03; training group: from 74.0±7.3% to 83.7±10.8%, p<0.01). Outside the target area only the training group showed a significant improvement (from 77.7±4.4% to 91.7±4.8%, p<0.01). Our data indicate a significant improvement in stress myocardial perfusion in the training group after 12 months. The ischaemia is reduced not only in the target region of the leading stenosis but also in other ischaemic myocardial areas. In contrast, after PTCA stress perfusion improves only in the initially ischaemic parts of the target area. (orig.)

  16. 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

  17. On-line monitoring of monoclonal antibody formation in high density perfusion culture using FIA.

    Science.gov (United States)

    Fenge, C; Fraune, E; Freitag, R; Scheper, T; Schügerl, K

    1991-05-01

    An automated flow injection system for on-line analysis of proteins in real fermentation fluids was developed by combining the principles of stopped-flow, merging zones flow injection analysis (FIA) with antigen-antibody reactions. IgG in the sample reacted with its corresponding antibody (a-IgG) in the reagent solution. Formation of insoluble immunocomplexes resulted in an increase of the turbidity which was determined photometrically. This system was used to monitor monoclonal antibody production in high cell density perfusion culture of hybridoma cells. Perfusion was performed with a newly developed static filtration unit equipped with hydrophilic microporous tubular membranes. Different sampling devices were tested to obtain a cell-free sample stream for on-line product analysis of high molecular weight (e.g., monoclonal antibodies) and low molecular weight (e.g., glucose, lactate) medium components. In fermentation fluids a good correlation (coefficient: 0.996) between the FIA method and an ELISA test was demonstrated. In a high density perfusion cultivation process mAb formation was successfully monitored on-line over a period of 400 h using a reliable sampling system. Glucose and lactate were measured over the same period of time using a commercially available automatic analyser based on immobilized enzyme technology.

  18. Schroedinger fluid

    International Nuclear Information System (INIS)

    Kan, K.K.

    1983-01-01

    The relationship of nuclear internal flow and collective inertia, the difference of this flow from that of a classical fluid, and the approach of this flow to rigid flow in independent-particle model rotation are elucidated by reviewing the theory of Schroedinger fluid and its implications for collective vibration and rotation. (author)

  19. Multiple-indicator dilution technique for characterization of normal and retrograde flow in once-through rat liver perfusions

    International Nuclear Information System (INIS)

    St-Pierre, M.V.; Schwab, A.J.; Goresky, C.A.; Lee, W.F.; Pang, K.S.

    1989-01-01

    The technique of normal and retrograde rat liver perfusion has been widely used to probe zonal differences in drug-metabolizing activities. The validity of this approach mandates the same tissue spaces being accessed by substrates during both normal and retrograde perfusions. Using the multiple-indicator dilution technique, we presently examine the extent to which retrograde perfusion alters the spaces accessible to noneliminated references. A bolus dose of 51Cr-labeled red blood cells, 125I-albumin, 14C-sucrose and 3H2O was injected into the portal (normal) or hepatic (retrograde) vein of rat livers perfused at 10 ml per min per liver. The outflow perfusate was serially collected over 220 sec to characterize the transit times and the distribution spaces of the labels. During retrograde perfusion, red blood cells, albumin and sucrose profiles peaked later and lower than during normal perfusion, whereas the water curves were similar. The transit times of red blood cells, albumin and sucrose were longer (p less than 0.005), whereas those for water did not change. Consequently, retrograde flow resulted in significantly larger sinusoidal blood volumes (45%), albumin Disse space (42%) and sucrose Disse space (25%) than during normal flow, whereas the distribution spaces for total and intracellular water remained unaltered. The distension of the vascular tree was confirmed by electron microscopy, by which occasional isolated foci of widened intercellular recesses and spaces of Disse were observed. Cellular ultrastructure was otherwise unchanged, and there was no difference found between normal and retrograde perfusion for bile flow rates, AST release, perfusion pressure, oxygen consumption and metabolic removal of ethanol, a substrate with flow-limited distribution, which equilibrates rapidly with cell water (hepatic extraction ratios were virtually identical: normal vs. retrograde, 0.50 vs. 0.48 at 6 to 7.4 mM input concentration)

  20. The anionic basis of fluid secretion by the rabbit mandibular salivary gland

    DEFF Research Database (Denmark)

    Case, R M; Hunter, M; Novak, I

    1984-01-01

    The role played by anions in salivary secretion has been studied in experiments on the isolated, perfused mandibular gland of the rabbit, in which perfusate Cl- and/or HCO3- were replaced by other anions. Replacement of Cl- with Br- had no significant effect on salivary secretion rate, but replac......The role played by anions in salivary secretion has been studied in experiments on the isolated, perfused mandibular gland of the rabbit, in which perfusate Cl- and/or HCO3- were replaced by other anions. Replacement of Cl- with Br- had no significant effect on salivary secretion rate...

  1. Optical modeling toward optimizing monitoring of intestinal perfusion in trauma patients

    Science.gov (United States)

    Akl, Tony J.; Wilson, Mark A.; Ericson, M. N.; Coté, Gerard L.

    2013-02-01

    Trauma is the number one cause of death for people between the ages 1 and 44 years in the United States. In addition, according to the Centers of Disease Control and Prevention, injury results in over 31 million emergency department visits annually. Minimizing the resuscitation period in major abdominal injuries increases survival rates by correcting impaired tissue oxygen delivery. Optimization of resuscitation requires a monitoring method to determine sufficient tissue oxygenation. Oxygenation can be assessed by determining the adequacy of tissue perfusion. In this work, we present the design of a wireless perfusion and oxygenation sensor based on photoplethysmography. Through optical modeling, the benefit of using the visible wavelengths 470, 525 and 590nm (around the 525nm hemoglobin isobestic point) for intestinal perfusion monitoring is compared to the typical near infrared (NIR) wavelengths (805nm isobestic point) used in such sensors. Specifically, NIR wavelengths penetrate through the thin intestinal wall ( 4mm) leading to high background signals. However, these visible wavelengths have two times shorter penetration depth that the NIR wavelengths. Monte-Carlo simulations show that the transmittance of the three selected wavelengths is lower by 5 orders of magnitude depending on the perfusion state. Due to the high absorbance of hemoglobin in the visible range, the perfusion signal carried by diffusely reflected light is also enhanced by an order of magnitude while oxygenation signal levels are maintained. In addition, short source-detector separations proved to be beneficial for limiting the probing depth to the thickness of the intestinal wall.

  2. Kinetics of reversible-sequestration of leukocytes by the isolated perfused rat lung

    Energy Technology Data Exchange (ETDEWEB)

    Goliaei, B.

    1980-08-01

    The kinetics and morphology of sequestration and margination of rat leukocytes were studied using an isolated perfused and ventilated rat lung preparation. Whole rat blood, bone marrow suspension, or leukocyte suspensions, were used to perfuse the isolated rat lung. The lung was also perfused with latex particle suspensions and the passage of particles through the lung capillaries was studied. When a leukocyte suspension was perfused through the lung in the single-pass mode, the rate of sequestration decreased as more cells were perfused. In contrast, latex particles of a size comparable to that of leukocytes were totally stopped by the lung. When the leukocyte suspension was recirculated through the lung, cells were rapidly removed from circulation until a steady state was reached, after which no net removal of cells by the lung occurred. These results indicate that leukocytes are reversibly sequestered from circulation. The sequestered cells marginated and attached to the luminal surface of the endothelium of post-capillary venules and veins. A mathematical model was developed based on the assumption that the attachment and detachment of leukocytes to blood vessel walls follows first-order kinetics. The model correctly predicts the following characteristics of the system: (a) the kinetics of the sequestration of leukocytes by the lung; (b) the existence of a steady state when a suspension of leukocytes is recirculated through the lung; and (c) the independence of the fraction of cells remaining in circulation from the starting concentration for all values of starting concentration. (ERB)

  3. Effects of Cooling Fluid Flow Rate on the Critical Heat Flux and Flow Stability in the Plate Fuel Type 2 MW TRIGA Reactor

    OpenAIRE

    H. P. Rahardjo; V. I. Sri Wardhani

    2017-01-01

    The conversion program of the 2 MW TRIGA reactor in Bandung consisted of the replacement of cylindrical fuel (produced by General Atomic) with plate fuel (produced by BATAN). The replacement led into the change of core cooling process from upward natural convection type to downward forced convection type, and resulted in different thermohydraulic safety criteria, such as critical heat flux (CHF) limit, boiling limit, and cooling fluid flow stability. In this paper, a thermohydraulic safety an...

  4. Preservation of the Myofascial Cuff During Posterior Fossa Surgery to Reduce the Rate of Pseudomeningocele Formation and Cerebrospinal Fluid Leak: A Technical Note

    OpenAIRE

    Felbaum, Daniel R; Mueller, Kyle; Anaizi, Amjad; Mason, Robert B; Jean, Walter C; Voyadzis, Jean M

    2016-01-01

    Introduction:?Suboccipital craniotomy is a workhorse neurosurgical operation for approaching the posterior fossa?but carries a high risk of pseudomeningocele and cerebrospinal fluid (CSF) leak. We describe our experience with a simple T-shaped fascial opening that preserves the occipital myofascial cuff as compared to traditional methods to reduce this risk. Methods:?A single institution, retrospective review of prospectively collected database was performed of patients that underwent a suboc...

  5. Improved visualization of delayed perfusion in lung MRI

    International Nuclear Information System (INIS)

    Risse, Frank; Eichinger, Monika; Kauczor, Hans-Ulrich; Semmler, Wolfhard; Puderbach, Michael

    2011-01-01

    Introduction: The investigation of pulmonary perfusion by three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was proposed recently. Subtraction images are generated for clinical evaluation, but temporal information is lost and perfusion defects might therefore be masked in this process. The aim of this study is to demonstrate a simple analysis strategy and classification for 3D-DCE-MRI perfusion datasets in the lung without omitting the temporal information. Materials and methods: Pulmonary perfusion measurements were performed in patients with different lung diseases using a 1.5 T MR-scanner with a time-resolved 3D-GRE pulse sequence. 25 3D-volumes were acquired after iv-injection of 0.1 mmol/kg KG Gadolinium-DTPA. Three parameters were determined for each pixel: (1) peak enhancement S n,max normalized to the arterial input function to detect regions of reduced perfusion; (2) time between arterial peak enhancement in the large pulmonary artery and tissue peak enhancement τ to visualize regions with delayed bolus onset; and (3) ratio R = S n,max /τ was calculated to visualize impaired perfusion, irrespectively of whether related to reduced or delayed perfusion. Results: A manual selection of peak perfusion images is not required. Five different types of perfusion can be found: (1) normal perfusion; (2) delayed non-reduced perfusion; (3) reduced non-delayed perfusion; (4) reduced and delayed perfusion; and (5) no perfusion. Types II and IV could not be seen in subtraction images since the temporal information is necessary for this purpose. Conclusions: The analysis strategy in this study allows for a simple and observer-independent visualization and classification of impaired perfusion in dynamic contrast-enhanced pulmonary perfusion MRI by using the temporal information of the datasets.

  6. Particle image velocimetry (PIV) study of rotating cylindrical filters for animal cell perfusion processes.

    Science.gov (United States)

    Figueredo-Cardero, Alvio; Chico, Ernesto; Castilho, Leda; de Andrade Medronho, Ricardo

    2012-01-01

    In the present work, the main fluid flow features inside a rotating cylindrical filtration (RCF) system used as external cell retention device for animal cell perfusion processes were investigated using particle image velocimetry (PIV). The motivation behind this work was to provide experimental fluid dynamic data for such turbulent flow using a high-permeability filter, given the lack of information about this system in the literature. The results shown herein gave evidence that, at the boundary between the filter mesh and the fluid, a slip velocity condition in the tangential direction does exist, which had not been reported in the literature so far. In the RCF system tested, this accounted for a fluid velocity 10% lower than that of the filter tip, which could be important for the cake formation kinetics during filtration. Evidence confirming the existence of Taylor vortices under conditions of turbulent flow and high permeability, typical of animal cell perfusion RCF systems, was obtained. Second-order turbulence statistics were successfully calculated. The radial behavior of the second-order turbulent moments revealed that turbulence in this system is highly anisotropic, which is relevant for performing numerical simulations of this system. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  7. The clinical application of SPECT myocardial perfusion imaging with 99mTc-MIBI

    International Nuclear Information System (INIS)

    Dong Weiyu

    1992-01-01

    This paper reported 182 SPECT myocardial perfusion images with China made 99m Tc-MIBI and were compared with ECG and UCG. The sensitivity of SPECT in ischemic were 91.2% and was higher than ECG (74.9%)and UCG (61.8%) (P < 0.01). And its specificity, accuracy and positive predictive rate were 78.3%, 90% and 97% respectively. Besides 9 cases have reverse distribution after exercise and rest images. In some ICD patients had shown their SPECT images, the perfusion defects in exercise as well as in rest image

  8. Vasopressin and angiotensin II stimulate oxygen uptake in the perfused rat hindlimb

    DEFF Research Database (Denmark)

    Colquhoun, E Q; Hettiarachchi, M; Ye, J M

    1988-01-01

    Vasopressin and angiotensin II markedly stimulated oxygen uptake in the perfused rat hindlimb. The increase due to each agent approached 70% of the basal rate, and was greater than that produced by a maximal concentration of norepinephrine. Half-maximal stimulation occurred at 60 pM vasopressin, 0...

  9. Application of a stir-tank bioreactor for perfusion culture and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-01-18

    Jan 18, 2010 ... The bioreactor we used could be an efficient cell culture system and demonstrates industrial potential. ... overcoming the harmful effects of browning have no conclusive .... solvent under reduced pressure, the ethanol extract liquids was re- ... was detected in the exhaust medium with a perfusion rate of more ...

  10. Clinical value, cost-effectiveness, and safety of myocardial perfusion scintigraphy: a position statement

    DEFF Research Database (Denmark)

    Marcassa, C.; Bax, J.J.; Bengel, F.

    2008-01-01

    Mortality rates due to coronary artery disease (CAD) have declined in recent years as result of improved prevention, diagnosis, and management. Nonetheless, CAD remains the leading cause of death worldwide with most casualties expected to occur in developing nations. Myocardial perfusion scintigr...

  11. [Myocardial perfusion scintigraphy. Exact and cost-effective coronary disease imaging - secondary publication

    DEFF Research Database (Denmark)

    Hesse, B.; Petersen, C.L.; Marcassa, C.

    2008-01-01

    Mortality rates due to coronary arterial disease (CAD) have declined as result of improved prevention, diagnosis and management, but CAD remains the leading cause of death. Myocardial perfusion scintigraphy (MPS) provides a cost-effective tool for early detection of CAD in symptomatic individuals...

  12. Thallium-201 exercise myocardial imaging to evaluate myocardial perfusion after coronary artery bypass surgery

    International Nuclear Information System (INIS)

    Hirzel, H.O.; Nuesch, K.; Sialer, G.; Horst, W.; Krayenbuehl, H.P.

    1980-01-01

    To assess the usefulness of thallium-201 exercise scintigraphy in evaluating myocardial perfusion after coronary artery bypass surgery, imaging was performed after submaximal bicycle ergometry and at rest in 54 patients before and within 24 +- 10 (SD) weeks after operation. Scintigraphy identified 8 out of 20 patients who were symptom free after operation and showed normal exercise electrocardiograms as still having exercise-induced ischaemia and thus as having not truly benefited from the surgical intervention. In contrast, improvement in perfusion was documented in 17 out of 31 patients despite further complaints of chest pain and persistence of a pathological exercise electrocardiogram in 6 of them. Bypass graft patency rate paralleled the scintigraphic findings in the 35 patients who were restudied arteriographically. It was concluded that thallium-201 exercise scintigraphy is a useful technique to document changes in regional perfusion after surgery and is definitely superior to the clinical evaluation of patients including the exercise electrocardiogram. (author)

  13. Increased sinusoidal volume and solute extraction during retrograde liver perfusion

    International Nuclear Information System (INIS)

    Bass, N.M.; Manning, J.A.; Weisiger, R.A.

    1989-01-01

    Retrograde isolated liver perfusion has been used to probe acinar functional heterogeneity, but the hemodynamic effects of backward flow have not been characterized. In this study, extraction of a long-chain fatty acid derivative, 12-N-methyl-7-nitrobenzo-2-oxa-1,3-diazol-amino stearate (12-NBDS), was greater during retrograde than during anterograde perfusion of isolated rat liver. To determine whether hemodynamic differences between anterograde and retrograde perfused livers could account for this finding, the hepatic extracellular space was measured for both directions of flow by means of [ 14 C]sucrose washout during perfusion as well as by direct measurement of [ 14 C]sucrose entrapped during perfusion. A three- to fourfold enlargement of the total hepatic extracellular space was found during retrograde perfusion by both approaches. Examination of perfusion-fixed livers by light microscopy and morphometry revealed that marked distension of the sinusoids occurred during retrograde perfusion and that this accounts for the observed increase in the [ 14 C]sucrose space. These findings support the hypothesis that maximum resistance to perfusate flow in the isolated perfused rat liver is located at the presinusoidal level. In addition, increased transit time of perfusate through the liver and greater sinusoidal surface area resulting from sinusoidal distension may account for the higher extraction of 12-NBDS and possibly other compounds by retrograde perfused liver

  14. Automatic Detection of Myocardial Boundaries in MR Cardio Perfusion Images

    NARCIS (Netherlands)

    Spreeuwers, Luuk; Breeuwer, Marcel

    2001-01-01

    Cardiovascular diseases often result in reduced blood perfusion of the myocardium (MC). Recent advances in MR allow fast recordingof contrast enhanced myocardial perfusion scans. For perfusion analysis the myocardial boundaries must be traced. Currently this is done manually. In this paper a method

  15. Quantitative 4D Transcatheter Intraarterial Perfusion MR Imaging as a Method to Standardize Angiographic Chemoembolization Endpoints

    Science.gov (United States)

    Jin, Brian; Wang, Dingxin; Lewandowski, Robert J.; Ryu, Robert K.; Sato, Kent T.; Larson, Andrew C.; Salem, Riad; Omary, Reed A.

    2011-01-01

    PURPOSE We aimed to test the hypothesis that subjective angiographic endpoints during transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) exhibit consistency and correlate with objective intraprocedural reductions in tumor perfusion as determined by quantitative four dimensional (4D) transcatheter intraarterial perfusion (TRIP) magnetic resonance (MR) imaging. MATERIALS AND METHODS This prospective study was approved by the institutional review board. Eighteen consecutive patients underwent TACE in a combined MR/interventional radiology (MR-IR) suite. Three board-certified interventional radiologists independently graded the angiographic endpoint of each procedure based on a previously described subjective angiographic chemoembolization endpoint (SACE) scale. A consensus SACE rating was established for each patient. Patients underwent quantitative 4D TRIP-MR imaging immediately before and after TACE, from which mean whole tumor perfusion (Fρ) was calculated. Consistency of SACE ratings between observers was evaluated using the intraclass correlation coefficient (ICC). The relationship between SACE ratings and intraprocedural TRIP-MR imaging perfusion changes was evaluated using Spearman’s rank correlation coefficient. RESULTS The SACE rating scale demonstrated very good consistency among all observers (ICC = 0.80). The consensus SACE rating was significantly correlated with both absolute (r = 0.54, P = 0.022) and percent (r = 0.85, P SACE rating scale demonstrates very good consistency between raters, and significantly correlates with objectively measured intraprocedural perfusion reductions during TACE. These results support the use of the SACE scale as a standardized alternative method to quantitative 4D TRIP-MR imaging to classify patients based on embolic endpoints of TACE. PMID:22021520

  16. The evaluation of dobutamine 99mTc-MIBI myocardial perfusion imaging in the diagnosis of coronary heart disease

    International Nuclear Information System (INIS)

    He Qing; Qu Wanying; Gong Junhui; Zhou Ying

    1996-01-01

    The method and the clinical value of dobutamine stress test as a substitute for exercise test in 99m Tc-MIBI myocardial perfusion imaging was investigated. 40 Patients were intravenously infused with dobutamine through IVAC syringe pumps by incremental doses, and 99m Tc-MIBI was injected at the peak dobutamine heart rate. The myocardial imaging was then performed. The rest myocardial imaging was done after 48 hours. 30 of the 31 patients with coronary heart disease showed reversible perfusion defects in dobutamine 99m Tc-MIBI myocardial perfusion images and 7 of the 9 patients without coronary heart disease showed normal images. The sensitivity of this test was 96.8% and the specificity 77.8%. None of the studies was discontinued due to dobutamine side effect. Dobutamine 99m Tc-MIBI myocardial perfusion imaging is a safe and sensitive method in the diagnosis of coronary heart disease

  17. [Evaluation of circulatory state using pulse oximeter: 2. PI (perfusion index) x PVI (pleth variability index)].

    Science.gov (United States)

    Kaneda, Toru; Suzuki, Toshiyasu

    2009-07-01

    Pulse oximeter expressed by SpO2 is used for monitoring respiratory state during operation and in ICU. Perfusion index (PI) and pleth variability index (PVI) as new indexes are calculated from pulse oximeter (Masimo SET Radical-7, Masimo Corp., USA, 1998) waveforms. And these indices were used as parameters to evaluate the circulatory state. For PI calculation, the pulsatile infrared signal is indexed against the nonpulsatile infrared signal and expressed as a percentage. It might thus be of future value in assessment of perioperative changes in peripheral perfusion. PVI is a measure of a dynamic change in PI that occurs during complete respiratory cycle. It might be thought that PVI, an index automatically derived from the pulse oximeter waveform analysis, had potentially clinical applications for noninvasive hypovolemia detection and fluid responsiveness monitoring.

  18. Spatial relationship between tumor perfusion and endogeneous glucose distribution

    International Nuclear Information System (INIS)

    Schroeder, T.; Larrier, N.; Viglianti, B.; Rabbani, Z.N.; Peltz, C.; Vujascovic, Z.; Dewhirst, M.W.

    2003-01-01

    Earlier studies detecting glucose in tissue and solid tumors by bioluminescence imaging suggested, that glucose distribution patterns may be spatially related to functional vascularity. The purpose of this study was to evaluate this relationship by comparing glucose distribution patterns as determined by bioluminescence imaging to perfusion patterns of endogeneous Hoechst 33342 in rats bearing mammary carcinomas. R 3230 mammary carcinoma cells have been implanted subcutaneously into 7 female Fischer 344 rats. Two months post implantation, after injection of Hoechst 33342 the tumors were removed and snap frozen to conserve metabolite levels. Concomitantly, blood was sampled from the animals for analysis of glucose concentrations using a micodialysis analyzer. Cryosections of the tumors have been prepared, and every slice has been analyzed for both, Hoechst binding by fluorescence microscopy, and for glucose distribution patterns using bioluminescence imaging. In many cases vascular structures could be retrieved by the spatial pattern of glucose distribution. In some cases however, higher glucose concentrations could be found independent from Hoechst signal. On the other hand, regions of high Hoechst signal are not necessarily correlated with high glucose concentrations. When comparing blood and tissue glucose levels, tissue glucose content as measured with bioluminescence imaging (1.9-3.5 mM) is considerably lower than blood glucose (5.6-8.0 mM), demonstrating the expected gradient from blood to tissue. This study demonstrates the feasibility of monitoring glucose gradients in relation to functional vasculature throughout the body, from blood down to tissue or tumor and further, throughout the microenvironment of the solid tumor. Glucose distribution patterns may be an important tool in perfusion studies, e. g. in detecting the direction of blood flow in ex-vivo samples or in estimating glucose consumption rates of tumor cells adjacent to or in between perfused

  19. Study of lung perfusion in colagenosis

    International Nuclear Information System (INIS)

    Macedo de Carvalho, A.C.; Calegaro, J.U.M.

    1982-01-01

    The lung involvement in the various types of colagenosis has been widely described in the literature. However, the study of lung perfusion utilizing radionuclides has been only mentioned in a few papers. With the intention of ascertaining the importance of the lung perfusion scanning in colagenosis, ten cases were studied, seven of which were females and three males, with the following pathologies: 4 rheumatoid arthritis, 4 systemic lupus eritematosous, 1 scleroderma and 1 scleroderma plus dermatomyositis. The ages of the patients varied from 20 to 73 years, and the duration of the disease from 1 month to 39 years. The lung scanning showed perfusion defects in 100% of the cases, not related with the type of colagenosis, duration of the disease, sex or age. On the other hand, the X rays study showed alterations in only 2 patients (20% of the cases). The ventilatory and respiratory functions were tested on 7 patients showing alteration (mixed pattern with predominance of the restrictive factor) in only one (14.3%), while the other patients were normal (85.7%). The importance of the lung perfusion scanning study in all patients with collagen vascular diseases is emphasized. (author) [es

  20. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo

    2010-01-01

    Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas ov...

  1. Study of lung perfusion in colagenosis

    Energy Technology Data Exchange (ETDEWEB)

    Macedo de Carvalho, A C; Calegaro, J U.M. [Fundacao Hospitalar do Distrito Federal, Distrito Federal (Brazil). Unidade de Medicina Nuclear

    1982-07-01

    The lung involvement in the various types of colagenosis has been widely described in the literature. However, the study of lung perfusion utilizing radionuclides has been only mentioned in a few papers. With the intention of ascertaining the importance of the lung perfusion scanning in colagenosis, ten cases were studied, seven of which were females and three males, with the following pathologies: 4 rheumatoid arthritis, 4 systemic lupus eritematosous, 1 scleroderma and 1 scleroderma plus dermatomyositis. The ages of the patients varied from 20 to 73 years, and the duration of the disease from 1 month to 39 years. The lung scanning showed perfusion defects in 100% of the cases, not related with the type of colagenosis, duration of the disease, sex or age. On the other hand, the X rays study showed alterations in only 2 patients (20% of the cases). The ventilatory and respiratory functions were tested on 7 patients showing alteration (mixed pattern with predominance of the restrictive factor) in only one (14.3%), while the other patients were normal (85.7%). The importance of the lung perfusion scanning study in all patients with collagen vascular diseases is emphasized.

  2. Acid perfusion test in gastroesophageal reflux disease

    Energy Technology Data Exchange (ETDEWEB)

    Kaul, B.; Petersen, H.; Grette, K.; Myrvold, H.E.

    1986-01-01

    An acid perfusion test, isotope scanning, endoscopy, and esophageal biopsy were performed in 101 patients with symptoms strongly suggestive of gastroesophageal reflux (GER) disease. A positive acid perfusion test within 30 min (APT) and within 5 min (TAPT) was found in 70.2% and 37.6% of the patients, respectively. A positive APT was found significantly more often in patients with than without endoscopic esophagitis, whereas a positive TAPT was found significantly more often in patients with severe symptoms than in patients with moderate symptoms, and in a significantly higher proportion of patients with than without GER by scintigraphy. Neither the APT nor the TAPT showed any dependency on the presence of histologic esophagitis. Most (97%) patients with a negative acid perfusion test, in addition to typical symptoms, also presented with scintigraphic, endoscopic, or histologic evidence of GER disease. Although it shows that the acid perfusion test, particularly when early positive, may serve as a weak predictor of the severity of GER disease, the present study gives little support to the test's clinical usefulness.

  3. Nuclear cardiology: Myocardial perfusion and function

    International Nuclear Information System (INIS)

    Seldin, D.W.

    1991-01-01

    Myocardial perfusion studies continue to be a major focus of research, with new investigations of the relationship of exercise-redistribution thallium imaging to diagnosis, prognosis, and case management. The redistribution phenomenon, which seemed to be fairly well understood a few years ago, is now recognized to be much more complex than originally thought, and various strategies have been proposed to clarify the meaning of persistent defects. Pharmacologic intervention with dipyridamole and adenosine has become available as an alternative to exercise, and comparisons with exercise imaging and catheterization results have been described. Thallium itself is no longer the sole single-photon perfusion radiopharmaceutical; two new technetium agents are now widely available. In addition to perfusion studies, advances in the study of ventricular function have been made, including reports of studies performed in conjunction with technetium perfusion studies, new insights into cardiac physiology, and the prognostic and case-management information that function studies provide. Finally, work has continued with monoclonal antibodies for the identification of areas of myocyte necrosis. 41 references

  4. Perfusion Quantification Using Gaussian Process Deconvolution

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke; Have, Anna Szynkowiak; Rasmussen, Carl Edward

    2002-01-01

    The quantification of perfusion using dynamic susceptibility contrast MRI (DSC-MRI) requires deconvolution to obtain the residual impulse response function (IRF). In this work, a method using the Gaussian process for deconvolution (GPD) is proposed. The fact that the IRF is smooth is incorporated...

  5. Estimation of intra-operator variability in perfusion parameter measurements using DCE-US.

    Science.gov (United States)

    Gauthier, Marianne; Leguerney, Ingrid; Thalmensi, Jessie; Chebil, Mohamed; Parisot, Sarah; Peronneau, Pierre; Roche, Alain; Lassau, Nathalie

    2011-03-28

    To investigate intra-operator variability of semi-quantitative perfusion parameters using dynamic contrast-enhanced ultrasonography (DCE-US), following bolus injections of SonoVue(®). The in vitro experiments were conducted using three in-house sets up based on pumping a fluid through a phantom placed in a water tank. In the in vivo experiments, B16F10 melanoma cells were xenografted to five nude mice. Both in vitro and in vivo, images were acquired following bolus injections of the ultrasound contrast agent SonoVue(®) (Bracco, Milan, Italy) and using a Toshiba Aplio(®) ultrasound scanner connected to a 2.9-5.8 MHz linear transducer (PZT, PLT 604AT probe) (Toshiba, Japan) allowing harmonic imaging ("Vascular Recognition Imaging") involving linear raw data. A mathematical model based on the dye-dilution theory was developed by the Gustave Roussy Institute, Villejuif, France and used to evaluate seven perfusion parameters from time-intensity curves. Intra-operator variability analyses were based on determining perfusion parameter coefficients of variation (CV). In vitro, different volumes of SonoVue(®) were tested with the three phantoms: intra-operator variability was found to range from 2.33% to 23.72%. In vivo, experiments were performed on tumor tissues and perfusion parameters exhibited values ranging from 1.48% to 29.97%. In addition, the area under the curve (AUC) and the area under the wash-out (AUWO) were two of the parameters of great interest since throughout in vitro and in vivo experiments their variability was lower than 15.79%. AUC and AUWO appear to be the most reliable parameters for assessing tumor perfusion using DCE-US as they exhibited the lowest CV values.

  6. Volume perfusion CT imaging of cerebral vasospasm: diagnostic performance of different perfusion maps

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Ahmed E. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Afat, Saif; Nikoubashman, Omid; Mueller, Marguerite; Wiesmann, Martin; Brockmann, Carolin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Schubert, Gerrit Alexander [RWTH Aachen University, Department of Neurosurgery, Aachen (Germany); Bier, Georg [Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Neuroradiology, Tuebingen (Germany); Brockmann, Marc A. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); University Hospital Mainz, Department of Neuroradiology, Mainz (Germany)

    2016-08-15

    In this study, we aimed to evaluate the diagnostic performance of different volume perfusion CT (VPCT) maps regarding the detection of cerebral vasospasm compared to angiographic findings. Forty-one datasets of 26 patients (57.5 ± 10.8 years, 18 F) with subarachnoid hemorrhage and suspected cerebral vasospasm, who underwent VPCT and angiography within 6 h, were included. Two neuroradiologists independently evaluated the presence and severity of vasospasm on perfusion maps on a 3-point Likert scale (0 - no vasospasm, 1 - vasospasm affecting <50 %, 2 - vasospasm affecting >50 % of vascular territory). A third neuroradiologist independently assessed angiography for the presence and severity of vasospasm on a 3-point Likert scale (0 - no vasospasm, 1 - vasospasm affecting < 50 %, 2 - vasospasm affecting > 50 % of vessel diameter). Perfusion maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to drain (TTD) were evaluated regarding diagnostic accuracy for cerebral vasospasm with angiography as reference standard. Correlation analysis of vasospasm severity on perfusion maps and angiographic images was performed. Furthermore, inter-reader agreement was assessed regarding findings on perfusion maps. Diagnostic accuracy for TTD and MTT was significantly higher than for all other perfusion maps (TTD, AUC = 0.832; MTT, AUC = 0.791; p < 0.001). TTD revealed higher sensitivity than MTT (p = 0.007). The severity of vasospasm on TTD maps showed significantly higher correlation levels with angiography than all other perfusion maps (p ≤ 0.048). Inter-reader agreement was (almost) perfect for all perfusion maps (kappa ≥ 0.927). The results of this study indicate that TTD maps have the highest sensitivity for the detection of cerebral vasospasm and highest correlation with angiography regarding the severity of vasospasm. (orig.)

  7. Detectable perfusion changes in MAG3 studies

    International Nuclear Information System (INIS)

    Shuter, B.; Bernar, A.; Roach, P.

    1998-01-01

    Full text: The use of 120 MBq 99m Tc-MAG 3 instead of 600 MBq 99m Tc-DTPA in renal imaging has degraded the images obtained during the perfusion phase. An increase of the minimum detectable change (MDC) in blood flow (BF) would also be expected. In transplant patients, renal BF is an important factor in patient management and the MDC should be small to allow early detection of reduced perfusion. We determined the mean and coefficient of variation (CoV: standard deviation/mean) of three renal perfusion indices as a function of counts in the time-activity curves (TACs). Transplant patients were given a dose of about 300 MBq of 99m Tc-MAG3 and images acquired at 8 fps for 60s. TACs made up from 8, 4, 2 or I images per second allowed calculation of renal perfusion indices as if doses of 300, 150, 75 and 38 MBq had been administered. Perfusion indices based on area under the TACs up to the arterial peak (API), the maximum slopes of the TACs (SPI) and the maximum slope of renal TAC and height of arterial TAC (BPI) were calculated by our routine renal software package. As the administered dose decreased, the CoV rose for all indices, least for BPI and most for API. BPI CoV increased from ∼10% at 300 MBq to 20% at 75 MBq, but API CoV rose from 6% to 46%. Mean BPI was stable over the dose range, but mean API showed a systematic increase of about 50% over the 300 MBq result. We conclude that at 120 MBq the MDC (expressed as 2*CoV) in BF is 30-60%, whereas at 600 MBq it may be as low as 10%, allowing earlier confident detection of a change in BF. The BPI was the preferred perfusion index as its mean value changed little and it had the least CoV at lower activities. The data also imply that relative kidney perfusion in the one individual will be much less accurate with 120 MBq of MAG 3

  8. Perfusion vector - a new method to quantify myocardial perfusion scintigraphy images: a simulation study with validation in patients

    DEFF Research Database (Denmark)

    Minarik, David; Senneby, Martin; Wollmer, Per

    2015-01-01

    Background The interpretation of myocardial perfusion scintigraphy (MPS) largely relies on visual assessment by the physician of the localization and extent of a perfusion defect. The aim of this study was to introduce the concept of the perfusion vector as a new objective quantitative method...

  9. Mesenchymal Stromal Cells as Anti-Inflammatory and Regenerative Mediators for Donor Kidneys During Normothermic Machine Perfusion.

    Science.gov (United States)

    Sierra-Parraga, Jesus Maria; Eijken, Marco; Hunter, James; Moers, Cyril; Leuvenink, Henri; Møller, Bjarne; Ploeg, Rutger J; Baan, Carla C; Jespersen, Bente; Hoogduijn, Martin J

    2017-08-15

    There is great demand for transplant kidneys for the treatment of end-stage kidney disease patients. To expand the donor pool, organs from older and comorbid brain death donors, so-called expanded criteria donors (ECD), as well as donation after circulatory death donors, are considered for transplantation. However, the quality of these organs may be inferior to standard donor organs. A major issue affecting graft function and survival is ischemia/reperfusion injury, which particularly affects kidneys from deceased donors. The development of hypothermic machine perfusion has been introduced in kidney transplantation as a preservation technique and has improved outcomes in ECD and marginal organs compared to static cold storage. Normothermic machine perfusion (NMP) is the most recent evolution of perfusion technology and allows assessment of the donor organ before transplantation. The possibility to control the content of the perfusion fluid offers opportunities for damage control and reparative therapies during machine perfusion. Mesenchymal stromal cells (MSC) have been demonstrated to possess potent regenerative properties via the release of paracrine effectors. The combination of NMP and MSC administration at the same time is a promising procedure in the field of transplantation. Therefore, the MePEP consortium has been created to study this novel modality of treatment in preparation for human trials. MePEP aims to assess the therapeutic effects of MSC administered ex vivo by NMP in the mechanisms of injury and repair in a porcine kidney autotransplantation model.

  10. Myocardial perfusion imaging by digital subtraction angiography

    International Nuclear Information System (INIS)

    Kadowaki, Hiroyuki; Ishikawa, Kinji; Ogai, Toshihiro; Katori, Ryo

    1986-01-01

    Several methods of digital subtraction angiography (DSA) were compared to determine which could better visualize regional myocardial perfusion using coronary angiography in seven patients with myocardial infarction, two with angina pectoris and five with normal coronary arteries. Satisfactory DSA was judged to be achieved if the shape of the heart on the mask film was identical to that on the live film and if both films were exactly superimposed. To obtain an identical mask film in the shape of each live film, both films were selected from the following three phases of the cardiac cycle; 1) at the R wave of the electrocardiogram, 2) 100 msec before the R wave, and 3) 200 msec before the R wave. The last two were superior for obtaining mask and live films which were similar in shape, because the cardiac motion in these phases was relatively small. Using these mask and live films, DSA was performed either with the continuous image mode (CI mode) or the time interval difference mode (TID mode). The overall perfusion of contrast medium through the artery to the vein was adequately visualized using the CI mode. Passage of contrast medium through the artery, capillary and vein was visualized at each phase using TID mode. Subtracted images were displayed and photographed, and the density of the contrast medium was adequate to display contour lines as in a relief map. Using this DSA, it was found that regional perfusion of the contrast medium was not always uniform in normal subjects, depending on the typography of the coronary artery. In all patients with anterior myocardial infarction, low perfusion was observed at the infarcted portion compared to the non-infarcted myocardium. In patients with inferior myocardial infarction, this low perfusion area was not observed because right coronary angiography was not subjected to DSA in this study. (J.P.N.)

  11. Basic consideration of diffusion/perfusion imaging

    International Nuclear Information System (INIS)

    Tamagawa, Yoichi; Kimura, Hirohiko; Matsuda, Tsuyoshi; Kawamura, Yasutaka; Nakatsugawa, Shigekazu; Ishii, Yasushi; Sakuma, Hajime; Tsukamoto, Tetsuji.

    1990-01-01

    In magnetic resonance imaging (MRI), microscopic motion of biological system such as molecular diffusion of water and microcirculation of blood in the capillary network (perfusion) has been proposed to cause signal attenuation as an intravoxel incoherent motion (IVIM). Quantitative imaging of the IVIM phenomenon was attempted to generate from a set of spin-echo (SE) sequences with or without sensitization by motion probing gradient (MPG). The IVIM imaging is characterized by a parameter, apparent diffusion coefficient (ADC), which is an integration of both the diffusion and the perfusion factor on voxel-by-voxel basis. Hard ware was adjusted to avoid image artifact mainly produced by eddy current. Feasibility of the method was tested using bottle phantom filled with water at different temperature and acetone, and the calculated ADC values of these media corresponded well with accepted values of diffusion. The method was then applied to biological system to investigate mutual participation of diffusion/perfusion on the ADC value. The result of tumor model born on nude mouse suggested considerable participation of perfusion factor which immediately disappeared after sacrificing the animal. Meanwhile, lower value of sacrificed tissue without microcirculation was suggested to have some restriction of diffusion factor by biological tissue. To substantiate the restriction effect on the diffusion, a series of observation have made on a fiber phantom, stalk of celory with botanical fibers and human brain with nerve fibers, in applying unidirectional MPG along the course of these banch of fiber system. The directional restriction effect of diffusion along the course of fiber (diffusion anisotrophy) was clearly visualized as directional change of ADC value. The present method for tissue characterization by diffusion/perfusion on microscopic level will provide a new insight for evaluation of functional derangement in human brain and other organs. (author)

  12. Ventilation-perfusion distribution in normal subjects.

    Science.gov (United States)

    Beck, Kenneth C; Johnson, Bruce D; Olson, Thomas P; Wilson, Theodore A

    2012-09-01

    Functional values of LogSD of the ventilation distribution (σ(V)) have been reported previously, but functional values of LogSD of the perfusion distribution (σ(q)) and the coefficient of correlation between ventilation and perfusion (ρ) have not been measured in humans. Here, we report values for σ(V), σ(q), and ρ obtained from wash-in data for three gases, helium and two soluble gases, acetylene and dimethyl ether. Normal subjects inspired gas containing the test gases, and the concentrations of the gases at end-expiration during the first 10 breaths were measured with the subjects at rest and at increasing levels of exercise. The regional distribution of ventilation and perfusion was described by a bivariate log-normal distribution with parameters σ(V), σ(q), and ρ, and these parameters were evaluated by matching the values of expired gas concentrations calculated for this distribution to the measured values. Values of cardiac output and LogSD ventilation/perfusion (Va/Q) were obtained. At rest, σ(q) is high (1.08 ± 0.12). With the onset of ventilation, σ(q) decreases to 0.85 ± 0.09 but remains higher than σ(V) (0.43 ± 0.09) at all exercise levels. Rho increases to 0.87 ± 0.07, and the value of LogSD Va/Q for light and moderate exercise is primarily the result of the difference between the magnitudes of σ(q) and σ(V). With known values for the parameters, the bivariate distribution describes the comprehensive distribution of ventilation and perfusion that underlies the distribution of the Va/Q ratio.

  13. Assessment of anatomic relation between pulmonary perfusion and morphology in pulmonary emphysema with breath-hold SPECT-CT fusion images

    International Nuclear Information System (INIS)

    Suga, Kazuyoshi; Kawakami, Yasuhiko; Iwanaga, Hideyuki; Hayashi, Noriko; Seto, Akiko; Matsunaga, Naofumi

    2008-01-01

    Anatomic relation between pulmonary perfusion and morphology in pulmonary emphysema was assessed on deep-inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images. Subjects were 38 patients with pulmonary emphysema and 11 non-smoker controls, who successfully underwent DIBrH and non-BrH perfusion SPECT using a dual-headed SPECT system during the period between January 2004 and June 2006. DIBrH SPECT was three-dimensionally co-registered with DIBrH CT to comprehend the relationship between lung perfusion defects and CT low attenuation areas (LAA). By comparing the appearance of lung perfusion on DIBrH with non-BrH SPECT, the correlation with the rate constant for the alveolar-capillary transfer of carbon monoxide (DLCO/VA) was compared between perfusion abnormalities on these SPECTs and LAA on CT. DIBrH SPECT provided fairly uniform perfusion in controls, but significantly enhanced perfusion heterogeneity when compared with non-BrH SPECT in pulmonary emphysema patients (P<0.001). The reliable DIBrH SPECT-CT fusion images confirmed more extended perfusion defects than LAA on CT in majority (73%) of patients. Perfusion abnormalities on DIBrH SPECT were more closely correlated with DLCO/VA than LAA on CT (P<0.05). DIBrH SPECT identifies affected lungs with perfusion abnormality better than does non-BrH SPECT in pulmonary emphysema. DIBrH SPECT-CT fusion images are useful for more accurately localizing affected lungs than morphologic CT alone in this disease. (author)

  14. Characteristics of Brain Perfusion in Patients of Parkinson's Disease

    International Nuclear Information System (INIS)

    Jeong, Young Jin; Park, Min Jung; Kim, Jae Woo; Kang, Young Kang

    2008-01-01

    It was well known that cerebral blood perfusion is normal or diffusely decreased in the majority of patients with Parkinson's disease (PD). Actually we interpreted brain perfusion SPECT images of PD patients in the clinical situation, we observed various cerebral perfusion patterns in patients with PD. So we performed brain perfusion SPECT to know the brain perfusion patterns of PD patients and the difference of perfusion patterns according to the sex and the age. Also we classified PD patients into small groups based on the brain perfusion pattern. Two hundred nineteen patients (M: 70, F: 149, mean age: 62.9±6.9 y/o) who were diagnosed as PD without dementia clinically and 55 patients (M: 15, F: 40, mean age: 61.4±9.2 y/o) as normal controls who had no past illness history were performed 99m Tc-HMPAO brain perfusion SPECT and neuropsychological test. At first, we compared all patients with PD and normal controls. Brain perfusion in left inferior frontal gyrus, left insula, left transverse temporal gyrus, left inferior parietal lobule, left superior parietal lobule, right precuneus, right caudate tail were lower in patients with PD than normal controls. Secondly, we compared male and female patients with PD and normal controls, respectively. Brain perfusion SPECT showed more decreased cerebral perfusion in left hemisphere than right side in both male and female patients compared to normal controls. And there was larger hypoperfusion area in female patients compared with male. Thirdly, we classified patients with PD and normal controls into 4 groups according to the age and compared brain perfusion respectively. In patient below fifties, brain perfusion in both occipitoparietal and left temporal lobe were lower in PD group. As the patients with PD grew older, hypoperfusion area were shown in both frontal, temporal and limbic lobes. Fourthly, We were able to divide patients into small groups based on cerebral perfusion pattern. There was normal cerebral blood

  15. An estimate of hydrothermal fluid residence times and vent chimney growth rates based on 210Pb/Pb ratios and mineralogic studies of sulfides dredged from the Juan de Fuca Ridge

    International Nuclear Information System (INIS)

    Kadko, D.; Tatsumoto, Mitsunobu

    1985-01-01

    The 210 Pb/Pb ratios across two sulfide samples dredged from the Juan de Fuca Ridge are used to estimate the growth rate of the sulfide material and the residence time of the hydrothermal fluid within the oceanic crust from the onset of basalt alteration. 210 Pb is added to the hydrothermal fluid by two processes: 1) high-temperature alteration of basalt and 2) if the residence time of the fluid is on the order of the 22.3-year half-life of 210 Pb, by in-situ growth from 222 Rn (Krishnaswami and Turekian, 1982). Stable lead is derived only from the alteration of basalt. The 210 Pb/Pb ratio across one sample was proportional 0.5 dpm/10 -6 g Pb, and across the other is was proportional 0.4 dpm/10 -6 g Pb. These values are quite close to the 238 U/Pb ratios of basalts from the area, suggesting that the residence time of the hydrothermal fluid from the onset of basalt alteration is appreciably less than the mean life of 210 Pb, i.e., the time required for ingrowth from the radon. An apparent growth rate of 1.2 cm/yr is derived from the slope of the 210 Pb/Pb curve for one of the samples. This is consistent with its mineralogy and texture which suggest an accretionary pattern of development. There is no obvious sequential growth pattern, and virtually no gradient in 210 Pb/Pb across the second sample. This is consistent with alteration of the original 210 Pb/Pb distribution by extensive remobilization reactions which are inferred from the mineralogic and textural relationships of the sample. (orig.)

  16. The efficacy of hypotonic and near-isotonic saline for parenteral fluid therapy given at low maintenance rate in preventing significant change in plasma sodium in post-operative pediatric patients: protocol for a prospective randomized non-blinded study

    Directory of Open Access Journals (Sweden)

    Stigzelius Shayarina

    2011-07-01

    Full Text Available Abstract Background Hyponatremia is the most frequent electrolyte abnormality observed in post-operative pediatric patients receiving intravenous maintenance fluid therapy. If plasma sodium concentration (p-Na+ declines to levels below 125 mmol/L in vs. restricted rate of infusion and the composition of solutions used for parenteral maintenance fluid therapy (hypotonic vs. isotonic solutions contribute to the development of hyponatremia. So far, there is no definitive pediatric data to support a particular choice of parenteral fluid for maintenance therapy in post-surgical patients. Methods/Design Our prospective randomized non-blinded study will be conducted in healthy children and adolescents aged 1 to 14 years who have been operated for acute appendicitis. Patients will be randomized either to intravenous hypotonic (0.23% or 0.40% sodium chloride in glucose, respectively or near-isotonic (0.81% sodium chloride in glucose solution given at approximately three-fourths of the average maintenance rate. The main outcome of interest from this study is to evaluate 24 h post-operatively whether differences in p-Na+ between treatment groups are large enough to be of clinical relevance. In addition, water and electrolyte balance as well as regulatory hormones will be measured. Discussion This study will provide valuable information on the efficacy of hypotonic and near-isotonic fluid therapy in preventing a significant decrease in p-Na+. Finally, by means of careful electrolyte and water balance and by measuring regulatory hormones our results will also contribute to a better understanding of the physiopathology of post-operative changes in p-Na+ in a population at risk for hyponatremia. Trial registration The protocol for this study is registered with the current controlled trials registry; registry number: ISRCTN43896775.

  17. Fluid dynamics

    CERN Document Server

    Bernard, Peter S

    2015-01-01

    This book presents a focused, readable account of the principal physical and mathematical ideas at the heart of fluid dynamics. Graduate students in engineering, applied math, and physics who are taking their first graduate course in fluids will find this book invaluable in providing the background in physics and mathematics necessary to pursue advanced study. The book includes a detailed derivation of the Navier-Stokes and energy equations, followed by many examples of their use in studying the dynamics of fluid flows. Modern tensor analysis is used to simplify the mathematical derivations, thus allowing a clearer view of the physics. Peter Bernard also covers the motivation behind many fundamental concepts such as Bernoulli's equation and the stream function. Many exercises are designed with a view toward using MATLAB or its equivalent to simplify and extend the analysis of fluid motion including developing flow simulations based on techniques described in the book.

  18. Validation and absolute quantification of MR perfusion compared with CT perfusion in patients with unilateral cerebral arterial stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Fang-Ying, E-mail: fychiou@hotmail.com [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China); Kao, Yi-Hsuan, E-mail: yhkao@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China); Teng, Michael Mu Huo, E-mail: mhteng@gmail.com [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China); School of Medicine, National Yang-Ming University, Taipei City, Taiwan (China); Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Chung, Hsiao-Wen, E-mail: chung@cc.ee.ntu.edu.tw [Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan (China); Chang, Feng-Chi, E-mail: fcchang374@gmail.com [School of Medicine, National Yang-Ming University, Taipei City, Taiwan (China); Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Cho, I-Chieh, E-mail: jessie8030@yahoo.com.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China); Chen, Wen-Chun, E-mail: sky7408695@hotmail.com [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei City, Taiwan (China)

    2012-12-15

    Objective: The aim of the study was to assess absolute quantification of dynamic susceptibility contrast-enhanced magnetic resonance perfusion (MRP) comparing with computed tomography perfusion (CTP) in patients with unilateral stenosis. Materials and methods: We retrospectively post-processed MRP in 20 patients with unilateral occlusion or stenosis of >79% at the internal carotid artery or the middle cerebral artery (MCA). Absolute quantification of MRP was performed after applying the following techniques: cerebrospinal fluid removal, vessel removal, and automatic segmentation of brain to calculate the scaling factors to convert relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) values to absolute values. For comparison between MRP and CTP, we manually deposited regions of interest in bilateral MCA territories at the level containing the body of the lateral ventricle. Results: The correlation between MRP and CTP was best for mean transit time (MTT) (r = 0.83), followed by cerebral blood flow (CBF) (r = 0.52) and cerebral blood volume (CBV) (r = 0.43). There was no significant difference between CTP and MRP for CBV, CBF, and MTT on the lesion side, the contralateral side, the lesion-contralateral differences, or the lesion-to-contralateral ratios (P > 0.05). The mean differences between MRP and CTP were as follows: CBV −0.57 mL/100 g, CBF 2.50 mL/100 g/min, and MTT −0.90 s. Conclusion: Absolute quantification of MRP is possible. Using the proposed method, measured values of MRP and CTP had acceptable linear correlation and quantitative agreement.

  19. Validation and absolute quantification of MR perfusion compared with CT perfusion in patients with unilateral cerebral arterial stenosis

    International Nuclear Information System (INIS)

    Chiu, Fang-Ying; Kao, Yi-Hsuan; Teng, Michael Mu Huo; Chung, Hsiao-Wen; Chang, Feng-Chi; Cho, I-Chieh; Chen, Wen-Chun

    2012-01-01

    Objective: The aim of the study was to assess absolute quantification of dynamic susceptibility contrast-enhanced magnetic resonance perfusion (MRP) comparing with computed tomography perfusion (CTP) in patients with unilateral stenosis. Materials and methods: We retrospectively post-processed MRP in 20 patients with unilateral occlusion or stenosis of >79% at the internal carotid artery or the middle cerebral artery (MCA). Absolute quantification of MRP was performed after applying the following techniques: cerebrospinal fluid removal, vessel removal, and automatic segmentation of brain to calculate the scaling factors to convert relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) values to absolute values. For comparison between MRP and CTP, we manually deposited regions of interest in bilateral MCA territories at the level containing the body of the lateral ventricle. Results: The correlation between MRP and CTP was best for mean transit time (MTT) (r = 0.83), followed by cerebral blood flow (CBF) (r = 0.52) and cerebral blood volume (CBV) (r = 0.43). There was no significant difference between CTP and MRP for CBV, CBF, and MTT on the lesion side, the contralateral side, the lesion-contralateral differences, or the lesion-to-contralateral ratios (P > 0.05). The mean differences between MRP and CTP were as follows: CBV −0.57 mL/100 g, CBF 2.50 mL/100 g/min, and MTT −0.90 s. Conclusion: Absolute quantification of MRP is possible. Using the proposed method, measured values of MRP and CTP had acceptable linear correlation and quantitative agreement.

  20. Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson

    International Nuclear Information System (INIS)

    Noel, Cory V.; Krishnamurthy, Ramkumar; Krishnamurthy, Rajesh; Moffett, Brady

    2017-01-01

    Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children. To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease. We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement. Regadenoson might be a safe and

  1. Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson

    Energy Technology Data Exchange (ETDEWEB)

    Noel, Cory V. [Baylor College of Medicine, Department of Pediatric Cardiology, Houston, TX (United States); Texas Children' s Hospital, Department of Pediatric Cardiology, Houston, TX (United States); Krishnamurthy, Ramkumar; Krishnamurthy, Rajesh [Texas Children' s Hospital, Department of Radiology, Houston, TX (United States); Moffett, Brady [Texas Children' s Hospital, Department of Pharmacology, Houston, TX (United States)

    2017-03-15

    Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children. To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease. We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement. Regadenoson might be a safe and

  2. Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot

    Energy Technology Data Exchange (ETDEWEB)

    Dowdle, S.C.; Human, D.G.; Mann, M.D. (Univ. of Cape Town (South Africa))

    1990-08-01

    Xenon-133 lung ventilation and perfusion scans were done preoperatively after cardiac catheterization and cineangiocardiography in 19 children; 6 had pulmonary atresia with an intact ventricular septum and hypoplastic right ventricle, 4 pulmonary atresia with associated complex univentricular heart, and 9 extreme Tetralogy of Fallot. The four patients with discrepancies in the sizes of the left and right pulmonary arteries on angiography had marked asymmetry of pulmonary perfusion and ventilation-perfusion imbalance on scintigraphy. Similar degrees of asymmetry and imbalance were present in 6 of the 15 children with equal-size pulmonary vessels. Asymmetry of pulmonary perfusion and ventilation-perfusion imbalance were associated with a poor prognosis.

  3. Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot

    International Nuclear Information System (INIS)

    Dowdle, S.C.; Human, D.G.; Mann, M.D.

    1990-01-01

    Xenon-133 lung ventilation and perfusion scans were done preoperatively after cardiac catheterization and cineangiocardiography in 19 children; 6 had pulmonary atresia with an intact ventricular septum and hypoplastic right ventricle, 4 pulmonary atresia with associated complex univentricular heart, and 9 extreme Tetralogy of Fallot. The four patients with discrepancies in the sizes of the left and right pulmonary arteries on angiography had marked asymmetry of pulmonary perfusion and ventilation-perfusion imbalance on scintigraphy. Similar degrees of asymmetry and imbalance were present in 6 of the 15 children with equal-size pulmonary vessels. Asymmetry of pulmonary perfusion and ventilation-perfusion imbalance were associated with a poor prognosis

  4. Improved Performance in Mammalian Cell Perfusion Cultures by Growth Inhibition.

    Science.gov (United States)

    Wolf, Moritz K F; Closet, Aurélie; Bzowska, Monika; Bielser, Jean-Marc; Souquet, Jonathan; Broly, Hervé; Morbidelli, Massimo

    2018-05-21

    Mammalian cell perfusion cultures represent a promising alternative to the current fed-batch technology for the production of various biopharmaceuticals. Long-term operation at a fixed viable cell density (VCD) requires a viable culture and a constant removal of excessive cells. Product loss in the cell removing bleed stream deteriorates the process yield. In this study, the authors investigate the use of chemical and environmental growth inhibition on culture performance by either adding valeric acid (VA) to the production media or by reducing the culture temperature (33.0 °C) with respect to control conditions (36.5 °C, no VA). Low temperature significantly reduces cellular growth, thus, resulting in lower bleed rates accompanied by a reduced product loss of 11% compared to 26% under control conditions. Additionally, the cell specific productivity of the target protein improves and maintained stable leading to media savings per mass of product. VA shows initially an inhibitory effect on cellular growth. However, cells seemed to adapt to the presence of the inhibitor resulting in a recovery of the cellular growth. Cell cycle and Western blot analyses support the observed results. This work underlines the role of temperature as a key operating variable for the optimization of perfusion cultures. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Treatment of tubal pregnancy by uterine artery perfusion and embolization

    International Nuclear Information System (INIS)

    Ni Caifang; Zou Jianwei; Zhao Hui; Jin Yonghai; Zhu Xiaoli; Liu Yizhi; He Qi; Shen Zhongji

    2006-01-01

    Objective: To study the feasibility, safety, and efficacy of the treatment for tubal pregnancy by interventional technique of transuterine arterial catheterization perfusion and embolization. Methods: Using modified Seldinger technique, 42 cases of tubal pregnancy received super-selective angiography of uterine artery, followed by perfusion of 50-100 mg methotrexate (MTX) through the catheter and embolization of uterine artery with gelatin sponge. Before and after the procedure, changes of clinical symptoms, physical signs, value of β-hCG and size of pregnancy cyst of patients were studied. Concentrations of MTX in peripheral blood were studied at 0.5, 6, 12, 24, 36, 48 hours after the procedure. Results: 38 out of 42 cases were cured with successful rate of 90.5%(38/42). The average time of β-hCG decreasing to normal was 8.26 ± 2.04 days. The concentration of MTX in peripheral blood with 50 mg or 75 mg dosage could not be detected at 36 hours after the procedure but could be detected as 0.01 μmol/L at 48 hours after the procedure with a dosage of 100 mg. Conclusions: It is simple, safe and efficient in performing trans-uterine artery chemo-embolization for therapy of fallopian tubal pregnancy, especially for those who complicated with manipules bleeding and also as the first choice for prevention of high risk massive hemorrhage. (authors)

  6. Percutaneous transluminal angioplasty combining intraarterial drug perfusion for the treatment of chronic lower limb ischemia

    International Nuclear Information System (INIS)

    Liu Yuan; He Chunshui; Liao Huaqiang; Zeng Wei; Zhang Hongwei; Liu Yang; Mu Yan; Liao Huaqiang; Guan Yongsong

    2008-01-01

    Objective: To evaluate the clinical effects of balloon angioplasty in combination with intraarterial perfusion of vasoactive drugs in the treatment of chronic lower limb ischemia. Methods: A total of 21 patients were treated with percutaneous transfemoral or transaxillary approach of balloon dilatation of the occlusive arterial segments, and then followed by perfusion of urokinase, Lipo prostaglandin E 1 and ginkgo leaf injection, respectively, into the responsible arteries via the catheter. Postoperatively, some of the patients with tibioperoneal arteries occlusion were perfused with the same drugs into their diseased arterial segments, one time per day altogether 5-7 times, through the ipsilateral femoral arterial sheath reserved temporarily, and then followed by observation for improvement of ischemia, superficial ulceration and gangrenous change. Results: Of the 21 patients, 20 were successfully treated with percutaneous transluminal balloon dilation and arterial perfusion with a technical successful rate of 95.2% (20/21). Five of the total 20 were additionally treated with the same drugs perfusion 5-7 days through the retained sheath, showing well patency. No serious complications occurred and ischemic symptoms of limbs improved, such as rest pain, claudication and dermo temperature. During 2-7 months follow-up, healing of skin ulcer occurred in 4 patients and breakoff of necrotic digits in 2 with the surface wound healed. Necrotic toes in all patients were dehydrated with stopping of necrosis and without any amputation. Conclusions: Percutaneous transluminal angioplasty combining intraarterial drug perfusion is safe and effective for promoting blood circulation with healing of ulceration and ceasing the development of lesions; with furthermore of maintaining the arterial patency through the retained vascular sheath for sustaining the drug plerfusion. (authors)

  7. Dual-energy perfusion-CT in recurrent pancreatic cancer. Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, F.; Skornitzke, S.; Kauczor, H.U.; Stiller, W.; Klauss, M. [Heidelberg Univ. (Germany). Clinic of Diagnostic and Interventional Radiology; Hackert, T. [Heidelberg Univ. (Germany). Clinic of Surgery; Grenacher, L. [Diagnostik Muenchen (Germany). Diagnostic Imaging Center

    2016-06-15

    To evaluate the diagnostic performance of dual energy (DE) perfusion-CT for the differentiation between postoperative soft-tissue formation and tumor recurrence in patients after potentially curative pancreatic cancer resection. 24 patients with postoperative soft-tissue formation in the conventional regular follow-up CT acquisition after pancreatic cancer resection with curative intent were included prospectively. They were examined with a 64-row dual-source CT using a dynamic sequence of 34 DE acquisitions every 1.5 s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). Weighted average (linearly blended M0.5) 120 kVp-equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool for estimating blood flow, permeability, and blood volume. Diagnosis was confirmed by histological study (n=4) and by regular follow-up. Final diagnosis was local recurrence of pancreatic cancer in 15 patients and unspecific postoperative tissue formation in 9 patients. The blood-flow values for recurrence tissue trended to be lower compared to postoperative tissue formation with 16.6 ml/100 ml/min and 24.7 ml/100 ml/min, respectively for weighted average 120 kVp-equivalent image data, which was not significant (n.s.) (p=0.06, significance level 0.05). Permeability- and blood-volume values were only slightly lower in recurrence tissue (n.s.). DE perfusion-CT is feasible in patients after pancreatic cancer resection and a promising functional imaging technique. As only a trend for lower perfusion values in local recurrence compared to unspecific postoperative alterations was found, the perfusion differences are not yet sufficient to differentiate between malignancy and unspecific postoperative alterations for this new technique. Further studies and technical improvements are needed to generate reliable data for this clinically highly relevant differentiation.

  8. Fluid overload in the ICU: evaluation and management.

    Science.gov (United States)

    Claure-Del Granado, Rolando; Mehta, Ravindra L

    2016-08-02

    Fluid overload is frequently found in acute kidney injury patients in critical care units. Recent studies have shown the relationship of fluid overload with adverse outcomes; hence, manage and optimization of fluid balance becomes a central component of the management of critically ill patients. In critically ill patients, in order to restore cardiac output, systemic blood pressure and renal perfusion an adequate fluid resuscitation is essential. Achieving an appropriate level of volume management requires knowledge of the underlying pathophysiology, evaluation of volume status, and selection of appropriate solution for volume repletion, and maintenance and modulation of the tissue perfusion. Numerous recent studies have established a correlation between fluid overload and mortality in critically ill patients. Fluid overload recognition and assessment requires an accurate documentation of intakes and outputs; yet, there is a wide difference in how it is evaluated, reviewed and utilized. Accurate volume status evaluation is essential for appropriate therapy since errors of volume evaluation can result in either in lack of essential treatment or unnecessary fluid administration, and both scenarios are associated with increased mortality. There are several methods to evaluate fluid status; however, most of the tests currently used are fairly inaccurate. Diuretics, especially loop diuretics, remain a valid therapeutic alternative. Fluid overload refractory to medical therapy requires the application of extracorporeal therapies. In critically ill patients, fluid overload is related to increased mortality and also lead to several complications like pulmonary edema, cardiac failure, delayed wound healing, tissue breakdown, and impaired bowel function. Therefore, the evaluation of volume status is crucial in the early management of critically ill patients. Diuretics are frequently used as an initial therapy; however, due to their limited effectiveness the use of continuous

  9. Hepatic perfusion changes in an experimental model of acute pancreatitis: Evaluation by perfusion CT

    Energy Technology Data Exchange (ETDEWEB)

    Tutcu, Semra [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey); Serter, Selim, E-mail: serterselim@gmail.co [Department of Radiology, Celal Bayar University, School of Medicine, Manisa (Turkey); Kaya, Yavuz; Kara, Eray [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey); Nese, Nalan [Department of Pathology, Celal Bayar University, School of Medicine, Manisa (Turkey); Pekindil, Goekhan [Department of Radiology, Celal Bayar University, School of Medicine, Manisa (Turkey); Coskun, Teoman [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey)

    2010-08-15

    Purpose: It is known that acute pancreatitis may cause secondary changes in several organs. Liver is one of these involved organs. In different experimental studies hepatic damages were shown histopathologically in acute pancreatitis but there are a few studies about perfusion disorders that accompany these histopathologic changes. Perfusion CT (pCT) provides the ability to detect regional and global alterations in organ blood flow. The purpose of the study was to describe hepatic perfusion changes in experimental acute pancreatitis model with pCT. Materials and methods: Forty Sprague-Dawley rats of both genders with average weights of 250 g were used. Rats were randomized into two groups. Twenty rats were in control group and 20 in acute pancreatitis group. pCT was performed. Perfusion maps were formed by processing the obtained images with perfusion CT software. Blood flow (BF) and blood volume (BV) values were obtained from these maps. All pancreatic and liver tissues were taken off with laparotomy and histopathologic investigation was performed. Student's t test was used for statistical analyses. Results: In pCT we found statistically significant increase in blood volume in both lobes of liver and in blood flow in right lobe of the liver (p < 0.01). Although blood flow in left lobe of the liver increased, it did not reach statistical significance. Conclusion: The quantitative analysis of liver parenchyma with pCT showed that acute pancreatitis causes a significant perfusion changes in the hepatic tissue. Systemic mediators seem to be effective as well as local inflammatory changes in perfusion changes.

  10. Hepatic perfusion changes in an experimental model of acute pancreatitis: Evaluation by perfusion CT

    International Nuclear Information System (INIS)

    Tutcu, Semra; Serter, Selim; Kaya, Yavuz; Kara, Eray; Nese, Nalan; Pekindil, Goekhan; Coskun, Teoman

    2010-01-01

    Purpose: It is known that acute pancreatitis may cause secondary changes in several organs. Liver is one of these involved organs. In different experimental studies hepatic damages were shown histopathologically in acute pancreatitis but there are a few studies about perfusion disorders that accompany these histopathologic changes. Perfusion CT (pCT) provides the ability to detect regional and global alterations in organ blood flow. The purpose of the study was to describe hepatic perfusion changes in experimental acute pancreatitis model with pCT. Materials and methods: Forty Sprague-Dawley rats of both genders with average weights of 250 g were used. Rats were randomized into two groups. Twenty rats were in control group and 20 in acute pancreatitis group. pCT was performed. Perfusion maps were formed by processing the obtained images with perfusion CT software. Blood flow (BF) and blood volume (BV) values were obtained from these maps. All pancreatic and liver tissues were taken off with laparotomy and histopathologic investigation was performed. Student's t test was used for statistical analyses. Results: In pCT we found statistically significant increase in blood volume in both lobes of liver and in blood flow in right lobe of the liver (p < 0.01). Although blood flow in left lobe of the liver increased, it did not reach statistical significance. Conclusion: The quantitative analysis of liver parenchyma with pCT showed that acute pancreatitis causes a significant perfusion changes in the hepatic tissue. Systemic mediators seem to be effective as well as local inflammatory changes in perfusion changes.

  11. A capillary-based perfusion phantom for simulation of brain perfusion for MRI

    International Nuclear Information System (INIS)

    Maciak, A.; Kronfeld, A.; Mueller-Forell, W.; Wille, C.; Kempski, O.; Stoeter, P.

    2010-01-01

    Purpose: The measurement of the CBF is a non-standardized procedure and there are no reliable gold standards. This abstract shows a capillary-based perfusion-phantom for CE-DSC-MRI. It has equivalent flow properties to those within the tissue capillary system of the human brain and allows the validation of the Siemens Perfusion (MR) software. Materials and Methods: The perfusion phantom consists of a dialyzer for the simulation of the capillary system, a feeding tube for simulation of the AIF and a pulsatile pump for simulation of the heart. Using this perfusion phantom, the exact determination of the gold standard CBF due to the well-known geometry of the phantom is easy. It was validated based on different perfusion measurements. These measurements were investigated with standard software (Siemens Perfusion MR). The software determined the CBF within the capillary system. Based on this CBF, a comparison to the gold standard was made with several different flow speeds. After AIF selection, a total of 726 CBF data points were automatically extracted by the software. Results: This results in a comparison of the gold standard CBF to these 726 CBF values. Therefore, a reproducible and reliable deviation estimation between gold standard CBF and measured CBF using the software was computed. It can be shown that the deviation between gold standard and software-based evaluation ranges between 1 and 31 %. Conclusion: There is no significance for any correlation between flow speed and amount of deviation. The mean measured CBF is 11.4 % higher than the gold standard CBF (p-value < 0.001). Using this kind of perfusion-phantom, the validation of different software systems allows reliable conclusions about their quality. (orig.)

  12. Can preoperative myocardial perfusion scintigraphy predict changes in left ventricular perfusion and function after coronary artery bypass graft surgery?

    DEFF Research Database (Denmark)

    Eckardt, Rozy; Kjeldsen, Bo Juel; Johansen, Allan

    2012-01-01

    OBJECTIVESWe wanted to evaluate whether preoperative myocardial perfusion scintigraphy (MPS) could predict changes in cardiac symptoms and postoperative myocardial perfusion and left ventricular function after coronary artery bypass grafting (CABG).METHODSNinety-two patients with stable angina...... in 26%. Left ventricular ejection fraction (LVEF), which was normal before operation in 45%, improved in 40% of all patients. The increase in LVEF was not related to the preoperative pattern of perfusion defects. Of 30 patients with normalized perfusion after CABG, 29 (97%) had reversible defects...... that reversible or partly reversible perfusion defects at a preoperative MPS have a high chance of normalized myocardial perfusion assessed by MPS 6 months after operation. Normal perfusion is obtained almost exclusively in territories with reversible ischaemia. Symptoms improved in nearly all patients and LVEF...

  13. Fluid management in infants and children during intracranial surgery

    Directory of Open Access Journals (Sweden)

    Hemangi S Karnik

    2017-01-01

    Full Text Available Fluid management in neurosurgical paediatric patients can be a real challenge due to their different pathophysiology, sensitivity to fluid loss, inability to accurately judge the degree of abnormality and adequacy of replacement in face of limited monitoring. For infants and children undergoing neurosurgical procedures, isotonic fluids should be used for maintenance and replacement to avoid increase in intracranial pressure and maintain cerebral perfusion. Routine use of added dextrose is not needed, but blood glucose monitoring should be done in high risk population. Preoperative deficits and intraoperative blood loss should be closely monitored and treated. Hyponataemia and other electrolyte derangements are common and should be monitored.

  14. The effect of age on outcomes after isolated limb perfusion for advanced extremity malignancies.

    Science.gov (United States)

    Smith, H G; Wilkinson, M J; Smith, M J F; Strauss, D C; Hayes, A J

    2018-06-22

    Isolated limb perfusion (ILP) is a well-established treatment for patients with advanced extremity malignancies unsuitable for limb-conserving surgery. However, little is known about the outcomes of this treatment in elderly patients. We sought to determine the effects of age on the tolerability and efficacy of ILP for advanced extremity malignancy. Patients undergoing ILP at our institution between January 2005 and January 2018 were identified from a prospectively maintained database. Patients were stratified by pathology (melanoma, soft-tissue sarcoma, other) and age (<75 years and ≥75 years). Outcomes of interest were perioperative morbidity and mortality, locoregional toxicities, response rates and oncological outcomes. During the study period, a total of 189 perfusions were attempted. Successful perfusions were performed in 179 patients, giving a technical success rate of 94.7%. No difference in perfusion success rates, severe locoregional toxicity and perioperative morbidity or mortality was noted between those aged <75 years and ≥75 years. The overall response rate in melanoma was 82.4%, and no difference in response rates or oncological outcomes between age groups was noted in these patients. The overall response rate in soft-tissue sarcoma was 63.5%, with no difference in response rates noted between age groups. However, patients aged <75 years with soft-tissue sarcoma had prolonged local recurrence-free survival compared with older patients (13 versus 6 months), possibly due to the prevalence of chemosensitive subtypes in the younger age group. ILP is an effective treatment for advanced extremity malignancies in the elderly, with comparable response rates and toxicities to younger patients. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  15. 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

  16. Nursing implications for Hepatic arterial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Ellender, R.

    1999-01-01

    Nurses working in Nuclear Medicine assist in Hepatic Artery Catheter (HAC) perfusion studies. This scan is not widely performed in Australia, the St George hospital for example performs approximately five per year. The purpose of this article is firstly to review the indications and rationale of HAC patency studies. Secondly, this article will stress the clinical implications for the Nuclear Medicine Nurse during this study. Emphasis will be placed on the importance of patient education during the procedure. A brief overview of hepatic anatomy and the radiopharmaceuticals administered during the scan is discussed. Finally, a step by step protocol is presented to show how the perfusion/ shunt study is performed. Copyright (1999) The Australian and New Zealand Society of Nuclear Medicine Inc

  17. Perfusion lung scintigraphy in primary pulmonary hypertension

    International Nuclear Information System (INIS)

    Ogawa, Y.; Hayashida, K.; Uehara, T.; Shimonagata, T.; Nishimura, T.; Osaka Univ., Suita

    1993-01-01

    15 cases of primary pulmonary hypertension were classified into two groups by patterns of perfusion lung scintigraphy. Perfusion scintigrams showed multiple, small, ill-defined defects (mottled + ve) pattern in eight cases, and the remaining seven cases had a normal (mottled - ve) pattern. The mean pulmonary arterial pressure in patients with a mottled pattern (54 ± 10 mmHg) was higher than in those with a normal pattern (42 ± 9 mmHg, p < 0.05). There were no significant differences between the two groups in right ventricular ejection fraction, partial pressures of oxygen in the arterial blood or alveolo-arterial oxygen difference. All the patients with a mottled pattern died within 2 years following the lung scintigraphy. There was a significant difference in the survival curves between the two groups. (author)

  18. Long-term outdoor cultivation by perfusing spent medium for biodiesel production from Chlorella minutissima.

    Science.gov (United States)

    Oh, Sung Ho; Kwon, Min Chul; Choi, Woon Yong; Seo, Yong Chang; Kim, Ga Bin; Kang, Do Hyung; Lee, Shin Young; Lee, Hyeon Yong

    2010-08-01

    A unique perfusion process was developed to maintain high concentrations of marine alga, Chlorella minutissima. This method is based on recycling cells by continuous feeding with warm spent sea water from nuclear power plants, which has very similar properties as sea water. A temperature of at least 30 degrees C in a 200 L photo-bioreactor was maintained in this system by perfusion of the thermal plume for 80 days in the coldest season. The maximum cell concentration and total lipid content was 8.3 g-dry wt./L and 23.2 %, w/w, respectively, under mixotrophic conditions. Lipid production was found to be due to a partially or non-growth related process, which implies that large amounts of biomass are needed for a high accumulation of lipids within the cells. At perfusion rates greater than 1.5 L/h, the temperature of the medium inside the reactor was around 30 degrees C, which was optimal for cell growth. For this system, a perfusion rate of 2.8 L/h was determined to be optimal for maintaining rapid cell growth and lipid production during outdoor cultivation. It was absolutely necessary to maintain the appropriate perfusion rate so that the medium temperature was optimal for cell growth. In addition, the lipids produced using this process were shown to be feasible for biodiesel production since the lipid composition of C. minutissima grown under these conditions consisted of 17 % (w/w) of C(16) and 47% (w/w) of C(18). The combined results of this study clearly demonstrated that the discharged energy of the thermal plume could be reused to cultivate marine alga by maintaining a relatively constant temperature in an outdoor photo-bioreactor without the need for supplying any extra energy, which could allow for cheap production of biodiesel from waste energy. Copyright 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  19. Cerebral perfution studies; Estudios de Perfusion Cerebral

    Energy Technology Data Exchange (ETDEWEB)

    Mut, Fernando [Universidad de la Republica, Montevideo (Uruguay). Centro de Medicina Nuclear

    1994-12-31

    For detecting in precocious form a coronary disease is necessary to aply a diagnostic techniques. The main considerations to be indicated in the present work are: physiological considerations, myocardial perfusion studies with radiotracers such as Talio 201, 99mTc, MIBI, 99mTc-Teboroxima, 99mTc-Fosfinas, instrumentation for obtain good images, proceedings protocols, studies interpretation, standards, SPECT, anomalies standards, coronary diseases.

  20. Myocardial perfusion imaging in hyperthrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Moorin, B.

    1998-01-01

    Full text: Patients with Hyperthrophic Cardiomyopathy (HCM) frequently suffer from syncope and cardiac arrest which may lead to sudden death. This is most often caused by ventricular arrhythmia's in adults, however in young patients the mechanisms are thought to be different. Ischaemia may play a significant role even in young asymptomatic HCM patients. The mechanisms of ischaemic development in HCM differ from those in the 'normal' myocardium (Due to intramural small vessel abnormalities and abnormal myocellular architecture). In HCM the coronary microcirculation is most often affected and massive hypertrophy means more energy is required to promote contraction thus increasing oxygen demand and compounding the effects of any ischaemic changes. A case of a 12 year old HCM patient is presented who has symptoms of syncope associated with exercise whose mother died suddenly of cardiac arrest developed from HCM. A myocardial perfusion rest/stress study was undertaken to detect any underlying myocardial ischaemia. Myocardial perfusion scintigraphy demonstrates any reduction in the microcirculation in addition to that present in the macrocirculation, unlike angiography which will only detect the latter. In this case the scan clearly showed evidence of ischaemia in the lateral wall and this may be an explanation for her episodes of syncope. We suggest an algorithm or the routine work-up of young patients with HCM which makes aggressive use of myocardial perfusion imaging to detect ischaemic changes. This may identify patients who are at higher risk and will assist with treatment decisions. We feel myocardial perfusion scintigraphy is a sensitive non-invasive accurate method of detecting microcirculatory ischaemia and is thus invaluable in HCM patients

  1. Myocardial perfusion studies in coronary diseases

    International Nuclear Information System (INIS)

    Mut, Fernando

    1994-01-01

    For detecting in precocious form a coronary disease is necessary to apply a diagnostic techniques. The main considerations to be indicated in the present work are: physiological considerations, myocardial perfusion studies with radiotracers such as Talio 201, 99mTc, MIBI, 99mTc-Teboroxima, 99mTc-Fosfinas, instrumentation for obtain good images,proceedings protocols, studies interpretation, standards, SPECT, anomalies standards, coronary diseases

  2. Non-contrast MRI perfusion angiosome in diabetic feet

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jie [Cardiovascular Imaging Lab, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Hastings, Mary K.; Mueller, Michael J. [Washington University School of Medicine, The Program in Physical Therapy, St. Louis, MO (United States); Muccigross, David; Hildebolt, Charles F. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Fan, Zhaoyang [Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Los Angeles, CA (United States); Gao, Fabao [West China Hospital, Sichuan University, Department of Radiology, Chengdu (China); Curci, John [Washington University School of Medicine, The Department of Surgery, St. Louis, MO (United States)

    2015-01-15

    The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

  3. Non-contrast MRI perfusion angiosome in diabetic feet

    International Nuclear Information System (INIS)

    Zheng, Jie; Hastings, Mary K.; Mueller, Michael J.; Muccigross, David; Hildebolt, Charles F.; Fan, Zhaoyang; Gao, Fabao; Curci, John

    2015-01-01

    The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

  4. Phosphorus NMR of isolated perfused morris hepatomas

    International Nuclear Information System (INIS)

    Graham, R.A.; Meyer, R.A.; Brown, T.R.; Sauer, L.A.

    1986-01-01

    The authors are developing techniques for the study of perfused solid tumors by NMR. Tissue-isolated solid hepatomas were grown to 1-2 cm diameter as described previously. The arterial supply was isolated and the tumors perfused (0.5 - 1.0 ml/min) in vitro at 25 C with a 15% suspension of red blood cells in Krebs-Henseliet solution. 31 P-NMR spectra were acquired at 162 MHz in a specially-designed NMR probe using a solenoidal coil. Intracellular pH (monitored from the chemical shift of inorganic phosphate) and ATP levels were stable for up to 6 hrs during perfusion. During 30 min of global ischemia, ATP decreased by 75% and pH fell from 7.0 to 6.7. These changes were reversed by 1 hr reperfusion. In addition to ATP and phosphate, the spectra included a large resonance due to phosphomonoesters, as well as peaks consistent with glycerylphosphocholine, glyceryl-phosphoethanolamine, phosphocreatine, NAD, and UDPG. However, the most novel feature of the spectra was the presence of an unidentified peak in the phosphonate region (+ 16.9 ppm). The peak was not present in spectra of muscle, liver, brain, kidney, or fat tissues excised from the same animals. They are presently attempting to identify the compound that gives rise to this peak and to establish its metabolic origin

  5. Can perfusion SPECT aid CTPA interpretation?

    International Nuclear Information System (INIS)

    Gradinscak, D. J.; Roach, P.; Bailey, E.; Kueh, S.

    2009-01-01

    Full text:Objective: To determine whether fusion of perfusion SPECT and CTPA improves the diagnostic accuracy of CTPA. Methods: 35 patients with suspected PE who underwent both CTPA and SPECT V/Q within 48 hours were included. Of these, the majority (n=30) had PE as determined by the V/Q SPECT scan and the others (n=5) were negative for PE. The clinical reports of CTPA were reviewed and pulmonary emboli tabulated based on anatomical location. A second radiologist, blinded to the results of the clinical read and the V/Q SPECT scan, reviewed the CTPA with and without perfusion SPECT fusion for assistance. Results: A total 57 PE were reported on the clinical reports and 60 PE identified on the blinded read. Fused CTPA/perfursion SPECT images identified a further 5 PE not identified on the clinical read (8% increase) and 2 PE not identified on the blinded read (3% increase). The additional emboli detected resulted in a change in final diagnosis from PE negative to PE positive in 2 patients (6%) compared with the clinical read and 1 patient (3%) compared with the blinded read without SPECT fusion. Conclusion: Fused CTPA-SPECT perfusion improves the sensitivity of CTPA for the detection of PE in a small number of patients. Fused data may help guide the radiologist to identify sites of PE on CTPA.

  6. Cerebral perfusion in homogeneity in normal volunteers

    International Nuclear Information System (INIS)

    Gruenwald, S.M.; Larcos, G.

    1998-01-01

    Full text: In the interpretation of cerebral perfusion scans, it is important to know the normal variation in perfusion which may occur between the cerebral hemispheres. For this reason 24 normal volunteers with no neurological or psychiatric history, and who were on no medications, had 99m Tc-HMPAO brain SPECT studies using a single headed gamma camera computer system. Oblique, coronal and sagittal images were reviewed separately by two experienced observers and any differences were resolved by consensus. Semi-quantitation was performed by summing two adjacent oblique slices and drawing right and left mirror image ROIs corresponding to the mid section level of anterior and posterior frontal lobes, anterior and posterior parietal lobes, temporal lobes and cerebellum. From the mean counts per pixel, right: left ROI ratios and ROI: cerebellar ratios were calculated. On qualitative review 6/24 subjects had mild asymmetry in tracer distribution between right and left cerebral lobes. Semi-quantitation revealed a 5-10% difference in counts between right and left ROIs in 12/24 subjects and an additional three subjects had 10-20% difference in counts between right and left temporal lobes. This study demonstrates the presence of mild asymmetry of cerebral perfusion in a significant minority of normal subjects

  7. Fluid Shifts

    Science.gov (United States)

    Stenger, M. B.; Hargens, A. R.; Dulchavsky, S. A.; Arbeille, P.; Danielson, R. W.; Ebert, D. J.; Garcia, K. M.; Johnston, S. L.; Laurie, S. S.; Lee, S. M. C.; hide

    2017-01-01

    Introduction. NASA's Human Research Program is focused on addressing health risks associated with long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but now more than 50 percent of ISS astronauts have experienced more profound, chronic changes with objective structural findings such as optic disc edema, globe flattening and choroidal folds. These structural and functional changes are referred to as the visual impairment and intracranial pressure (VIIP) syndrome. Development of VIIP symptoms may be related to elevated intracranial pressure (ICP) secondary to spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to determine if a relation exists with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as any VIIP-related effects of those shifts, are predicted by the crewmember's pre-flight status and responses to acute hemodynamic manipulations, specifically posture changes and lower body negative pressure. Methods. We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, and calcaneus tissue thickness (by ultrasound); (3) vascular dimensions by ultrasound (jugular veins, cerebral and carotid arteries, vertebral arteries and veins, portal vein); (4) vascular dynamics by MRI (head/neck blood flow, cerebrospinal fluid

  8. Towards robust deconvolution of low-dose perfusion CT: Sparse perfusion deconvolution using online dictionary learning

    Science.gov (United States)

    Fang, Ruogu; Chen, Tsuhan; Sanelli, Pina C.

    2014-01-01

    Computed tomography perfusion (CTP) is an important functional imaging modality in the evaluation of cerebrovascular diseases, particularly in acute stroke and vasospasm. However, the post-processed parametric maps of blood flow tend to be noisy, especially in low-dose CTP, due to the noisy contrast enhancement profile and the oscillatory nature of the results generated by the current computational methods. In this paper, we propose a robust sparse perfusion deconvolution method (SPD) to estimate cerebral blood flow in CTP performed at low radiation dose. We first build a dictionary from high-dose perfusion maps using online dictionary learning and then perform deconvolution-based hemodynamic parameters estimation on the low-dose CTP data. Our method is validated on clinical data of patients with normal and pathological CBF maps. The results show that we achieve superior performance than existing methods, and potentially improve the differentiation between normal and ischemic tissue in the brain. PMID:23542422

  9. Pulmonary artery perfusion versus no perfusion during cardiopulmonary bypass for open heart surgery in adults

    DEFF Research Database (Denmark)

    Buggeskov, Katrine B; Grønlykke, Lars; Risom, Emilie C

    2018-01-01

    BACKGROUND: Available evidence has been inconclusive on whether pulmonary artery perfusion during cardiopulmonary bypass (CPB) is associated with decreased or increased mortality, pulmonary events, and serious adverse events (SAEs) after open heart surgery. To our knowledge, no previous systematic...... handsearched retrieved study reports and scanned citations of included studies and relevant reviews to ensure that no relevant trials were missed. We searched for ongoing trials and unpublished trials in the World Health Organization International Clinical Trials Registry Platform (ICTRP) and at clinicaltrials......). We used GRADE principles to assess the quality of evidence. MAIN RESULTS: We included in this review four RCTs (210 participants) reporting relevant outcomes. Investigators randomly assigned participants to pulmonary artery perfusion with blood versus no perfusion during CPB. Only one trial included...

  10. Kidney in potassium depletion. II. K+ handling by the isolated perfused rat kidney

    International Nuclear Information System (INIS)

    Hayashi, M.; Katz, A.I.

    1987-01-01

    In a companion paper the authors reported a large increment in Na + -K + -ATPase activity and [ 3 H]ouabain binding the inner stripe of outer medullary collecting tubules from K-depleted rats. To test the hypothesis that the increased number of Na + -K + pumps in these animals may be involved in potassium reabsorption they examined the effect of ouabain on K excretion by isolated, perfused kidneys from rats fed a K-free diet for 3 wk. Kidneys from K-depleted rats retain potassium avidly, both the fractional (FE/sub K/) and absolute K excretion being approximately fivefold lower than in control kidneys. Ouabain (5 mM) increased FE/sub K/ in kidneys from each K-depleted rat; similar results were obtained when kidneys were perfused with low and high potassium concentrations. In contrast, ouabain produced a variable effect in control kidneys, that depended on the perfusate potassium concentration. In K-depleted rats amiloride did not significantly alter K excretion and did not block the ouabain-induced kaliuresis, suggesting that the latter is not due to enhanced secretion secondary to increased distal fluid delivery. These results provide evidence for ouabain-sensitive potassium reabsorption in kidneys of chronically K-depleted rats, and suggest an explanation for the increased Na + -K + -ATPase observed in such animals

  11. Drug perfusion enhancement in tissue model by steady streaming induced by oscillating microbubbles.

    Science.gov (United States)

    Oh, Jin Sun; Kwon, Yong Seok; Lee, Kyung Ho; Jeong, Woowon; Chung, Sang Kug; Rhee, Kyehan

    2014-01-01

    Drug delivery into neurological tissue is challenging because of the low tissue permeability. Ultrasound incorporating microbubbles has been applied to enhance drug delivery into these tissues, but the effects of a streaming flow by microbubble oscillation on drug perfusion have not been elucidated. In order to clarify the physical effects of steady streaming on drug delivery, an experimental study on dye perfusion into a tissue model was performed using microbubbles excited by acoustic waves. The surface concentration and penetration length of the drug were increased by 12% and 13%, respectively, with streaming flow. The mass of dye perfused into a tissue phantom for 30s was increased by about 20% in the phantom with oscillating bubbles. A computational model that considers fluid structure interaction for streaming flow fields induced by oscillating bubbles was developed, and mass transfer of the drug into the porous tissue model was analyzed. The computed flow fields agreed with the theoretical solutions, and the dye concentration distribution in the tissue agreed well with the experimental data. The computational results showed that steady streaming with a streaming velocity of a few millimeters per second promotes mass transfer into a tissue. © 2013 Published by Elsevier Ltd.

  12. Fluid mechanics

    International Nuclear Information System (INIS)

    Granger, R.A.

    1985-01-01

    This text offers the most comprehensive approach available to fluid mechanics. The author takes great care to insure a physical understanding of concepts grounded in applied mathematics. The presentation of theory is followed by engineering applications, helping students develop problem-solving skills from the perspective of a professional engineer. Extensive use of detailed examples reinforces the understanding of theoretical concepts

  13. Rapid intravenous infusion of 20 mL/kg saline alters the distribution of perfusion in healthy supine humans.

    Science.gov (United States)

    Henderson, A C; Sá, R C; Barash, I A; Holverda, S; Buxton, R B; Hopkins, S R; Prisk, G K

    2012-03-15

    Rapid intravenous saline infusion, a model meant to replicate the initial changes leading to pulmonary interstitial edema, increases pulmonary arterial pressure in humans. We hypothesized that this would alter lung perfusion distribution. Six healthy subjects (29 ± 6 years) underwent magnetic resonance imaging to quantify perfusion using arterial spin labeling. Regional proton density was measured using a fast-gradient echo sequence, allowing blood delivered to the slice to be normalized for density and quantified in mL/min/g. Contributions from flow in large conduit vessels were minimized using a flow cutoff value (blood delivered > 35% maximum in mL/min/cm(3)) in order to obtain an estimate of blood delivered to the capillary bed (perfusion). Images were acquired supine at baseline, after infusion of 20 mL/kg saline, and after a short upright recovery period for a single sagittal slice in the right lung during breath-holds at functional residual capacity. Thoracic fluid content measured by impedance cardiography was elevated post-infusion by up to 13% (pchanges in conduit vessels, there were no significant changes in perfusion in dependent lung following infusion (7.8 ± 1.9 mL/min/g baseline, 7.9 ± 2.0 post, 8.5 ± 2.1 recovery, p=0.36). There were no significant changes in lung density. These data suggest that saline infusion increased perfusion to nondependent lung, consistent with an increase in intravascular pressures. Dependent lung may have been "protected" from increases in perfusion following infusion due to gravitational compression of the pulmonary vasculature. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Prior, John O.; Calcagni, Maria-Lucia; Bischof Delaloye, Angelika; Monbaron, David; Ruiz, Juan; Koehli, Melanie

    2005-01-01

    Silent myocardial ischaemia - as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain - is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, 99m Tc-sestamibi, 201 Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). Abnormal MPS (SSS≥4) was observed in 49 (37%) patients (SSS=4.9±8.4, SDS=2.4±4.7), reversible perfusion defects (SDS≥2) in 40 (30%) patients [SSS=13.3±10.9; SDS=8.0±5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9±11.3; SDS=7.4±1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress (odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify these patients with a

  15. Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Prior, John O.; Calcagni, Maria-Lucia; Bischof Delaloye, Angelika [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Nuclear Medicine, Lausanne (Switzerland); Monbaron, David; Ruiz, Juan [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Endocrinology, Diabetology and Metabolism, Lausanne (Switzerland); Koehli, Melanie [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Nuclear Medicine, Lausanne (Switzerland); Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Endocrinology, Diabetology and Metabolism, Lausanne (Switzerland)

    2005-01-01

    Silent myocardial ischaemia - as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain - is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, {sup 99m}Tc-sestamibi, {sup 201}Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). Abnormal MPS (SSS{>=}4) was observed in 49 (37%) patients (SSS=4.9{+-}8.4, SDS=2.4{+-}4.7), reversible perfusion defects (SDS{>=}2) in 40 (30%) patients [SSS=13.3{+-}10.9; SDS=8.0{+-}5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9{+-}11.3; SDS=7.4{+-}1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress (odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify

  16. Developing a Benchmarking Process in Perfusion: A Report of the Perfusion Downunder Collaboration

    Science.gov (United States)

    Baker, Robert A.; Newland, Richard F.; Fenton, Carmel; McDonald, Michael; Willcox, Timothy W.; Merry, Alan F.

    2012-01-01

    Abstract: Improving and understanding clinical practice is an appropriate goal for the perfusion community. The Perfusion Downunder Collaboration has established a multi-center perfusion focused database aimed at achieving these goals through the development of quantitative quality indicators for clinical improvement through benchmarking. Data were collected using the Perfusion Downunder Collaboration database from procedures performed in eight Australian and New Zealand cardiac centers between March 2007 and February 2011. At the Perfusion Downunder Meeting in 2010, it was agreed by consensus, to report quality indicators (QI) for glucose level, arterial outlet temperature, and pCO2 management during cardiopulmonary bypass. The values chosen for each QI were: blood glucose ≥4 mmol/L and ≤10 mmol/L; arterial outlet temperature ≤37°C; and arterial blood gas pCO2 ≥ 35 and ≤45 mmHg. The QI data were used to derive benchmarks using the Achievable Benchmark of Care (ABC™) methodology to identify the incidence of QIs at the best performing centers. Five thousand four hundred and sixty-five procedures were evaluated to derive QI and benchmark data. The incidence of the blood glucose QI ranged from 37–96% of procedures, with a benchmark value of 90%. The arterial outlet temperature QI occurred in 16–98% of procedures with the benchmark of 94%; while the arterial pCO2 QI occurred in 21–91%, with the benchmark value of 80%. We have derived QIs and benchmark calculations for the management of several key aspects of cardiopulmonary bypass to provide a platform for improving the quality of perfusion practice. PMID:22730861

  17. Magnetic Resonance Imaging of Ventilation and Perfusion in the Lung

    Science.gov (United States)

    Prisk, Gordon Kim (Inventor); Hopkins, Susan Roberta (Inventor); Buxton, Richard Bruce (Inventor); Pereira De Sa, Rui Carlos (Inventor); Theilmann, Rebecca Jean (Inventor); Cronin, Matthew Vincent (Inventor)

    2017-01-01

    Methods, devices, and systems are disclosed for implementing a fully quantitative non-injectable contrast proton MRI technique to measure spatial ventilation-perfusion (VA/Q) matching and spatial distribution of ventilation and perfusion. In one aspect, a method using MRI to characterize ventilation and perfusion in a lung includes acquiring an MR image of the lung having MR data in a voxel and obtaining a breathing frequency parameter, determining a water density value, a specific ventilation value, and a perfusion value in at least one voxel of the MR image based on the MR data and using the water density value to determine an air content value, and determining a ventilation-perfusion ratio value that is the product of the specific ventilation value, the air content value, the inverse of the perfusion value, and the breathing frequency.

  18. Myocardial perfusion in type 2 diabetes with left ventricular hypertrophy

    DEFF Research Database (Denmark)

    Hesse, Birger; Meyer, Christian; Nielsen, Flemming S

    2004-01-01

    The purpose of this study was to assess whether acute angiotensin-converting enzyme (ACE) inhibition would improve myocardial perfusion and perfusion reserve in a subpopulation of normotensive patients with diabetes and left ventricular hypertrophy (LVH), both independent risk factors of coronary...... disease. Using positron emission tomography (PET), we investigated the response of regional myocardial perfusion to acute ACE inhibition with i.v. infusion of perindoprilat (vs saline infusion as control, minimum interval 3 days) in 12 diabetic patients with LVH. Myocardial perfusion was quantified...... with controls, maximal perfusion was reduced in patients (1.8+/-0.6 vs 2.5+/-1.0 ml min(-1) g(-1); P2.7+/-1.0 vs 3.6+/-1.3; P=0.059). During perindoprilat infusion, myocardial perfusion reserve in patients increased to 3.9+/-0.9 ( P

  19. Reversible ventilation and perfusion abnormalities in unilateral obstructed lung

    International Nuclear Information System (INIS)

    Ward, H.E.; Jones, R.L.; King, E.G.; Sproule, B.J.; Fortune, R.L.

    1982-01-01

    An intraluminal carcinoid tumor obstructing the left mainstem bronchus produced hypoxemia through alteration in ventilation/perfusion matching. Studies of regional lung function using 133-xenon (/sup 133/Xe) and a multiprobe computerized instrumentation system documented a reduction of perfusion to 22 percent and ventilation to 6 percent of the total. There was negligible washout of intravenously injected /sup 133/Xe from the left lung consistent with air trapping. Four days after left mainstem bronchial sleeve resection, perfusion, ventilation and washout of injected xenon had significantly improved and by four months postresection, all measurements were virtually normal, although complete restoration of perfusion in relation to ventilation was delayed. Regional lung function studied with a multiprobe system in this patient provided a clinical model for the study of ventilation and perfusion inter-relationships in large airway obstruction and demonstrated that a prolonged time may be required for return of perfusion to normal

  20. Prediction of residual lung function after lung surgery, and examination of blood perfusion in the pre- and postoperative lung using three-dimensional SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Shimatani, Shinji [Toho Univ., Tokyo (Japan). School of Medicine

    2001-01-01

    In order to predict postoperative pulmonary function after lung surgery, preoperative {sup 99m}Tc-macroaggregated albumin (MAA) lung perfusion scans with single-photon emission computed tomography (SPECT) were performed. Spirometry was also performed before and 4-6 months after surgery in 40 patients. In addition, changes in blood perfusion in the pre- and postoperative lung were examined by postoperative lung perfusion scans in 18 of the 40 patients. We measured the three-dimensional (3-D) imaging volume of the operative and contralateral lungs using the volumes rendering method at blood perfusion thresholds of 20, 50 and 75%, utilizing {sup 99m}Tc-MAA lung perfusion, and predicted pulmonary function by means of the measured volumes. We examined the correlation between predicted and the measured values of postoperative pulmonary function, forced vital capacity (FVC) and forced expiratory volume in one second (FEV{sub 1.0}). The correlation between FEV{sub 1.0} predicted by SPECT (threshold 50%) and measured postoperative lung function resembled that between lung function predicted by the standard planar method and measured FEV{sub 1.0} in the lobectomy group. We then examined the ratios of both pre- and postoperative blood perfusion volumes obtained using 3-D imaging at lung perfusion threshold ranges of 10% each (PV20-29, PV30-39) to pre- and postoperative total perfusion (PV20-100). In the lobectomy group, the postoperative PV20-29/PV20-100 value was significantly higher for the operative side lung than the preoperative PV20-29/PV20-100 value, and the postoperative PV50-59, 60-69, 70-79, 80-89 and 90-100/PV20-100 values were significantly lower than the respective preoperative values. However, in the contralateral lung, the respective pre- and postoperative PV/PV20-100 values were almost identical. These findings suggest that the rate of low blood perfusion increased while the rate of middle to high perfusion decreased in the lobectomy group in the operative

  1. Dynamic CT Perfusion Imaging for the Detection of Crossed Cerebellar Diaschisis in Acute Ischemic Stroke

    International Nuclear Information System (INIS)

    Jeon, Young Wook; Kim, Seo Hyun; Lee, Ji Young; Whang, Kum; Kim, Myung Soon; Kim, Young Ju; Lee, Myeong Sub; Brain Reserch Group

    2012-01-01

    Although the detection of crossed cerebellar diaschisis (CCD) by means of different imaging modalities is well described, little is known about its diagnosis by computed tomography perfusion (CTP) imaging. We investigated the detection rate of CCD by CTP imaging and the factors related to CCD on CTP images in patients with acute ischemic stroke. CT perfusion maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time-to-peak (TTP) obtained from 81 consecutive patients affected by an acute ischemic stroke were retrospectively reviewed. Whole-brain perfusion maps were obtained with a multichannel CT scanner using the toggling-table technique. The criteria for CCD was a unilateral supratentorial ischemic lesion and an accompanying decrease in perfusion of the contralateral cerebellar hemisphere on the basis of CTP maps by visual inspection without a set threshold. Maps were quantitatively analyzed in CCD positive cases. The criteria for CCD were fulfilled in 25 of the 81 cases (31%). Detection rates per CTP map were as follows: MTT (31%) > TTP (21%) > CBF (9%) > CBV (6%). Supratentorial ischemic volume, degree of perfusion reduction, and infratentorial asymmetry index correlated strongly (R, 0.555-0.870) and significantly (p < 0.05) with each other in CCD-positive cases. It is possible to detect CCD on all four of the CTP-based maps. Of these maps, MTT is most sensitive in detecting CCD. Our data indicate that CTP imaging is a valid tool for the diagnosis of CCD in patients affected by an acute hemispheric stroke.

  2. Modelling of fluid flow through short tube orifices under metastable conditions: A new numerical validation approach for evaluating the mass flow rate with refrigerant mixtures (HFC-407C and HFC-410A)

    International Nuclear Information System (INIS)

    García-Valladares, O.; Santoyo, E.

    2014-01-01

    In a previous work, one-dimensional numerical modelling of fluid-flow inside short tube orifices was performed, and successfully validated against a wide range of mass flow rate measurements reported for the refrigerant HFC-134a. Governing equations of continuity, momentum, energy and entropy were solved for describing the fluid flow under a wide variety of thermodynamic transitions (e.g., subcooled liquid region, metastable liquid region, metastable two-phase region and equilibrium two-phase region), including sudden contraction and enlargement. In this new study, a comprehensive comparison analysis between numerical simulation data and experimental measurements obtained for HFC-407C and HFC-410A refrigerants (N o  = 241) to extend the applicability of the same mathematical model was carried out. Using a widespread statistical analysis, based on weighted linear regressions with an outlier detection/rejection module at 95% of confidence level, the prediction performance of the mathematical model was again assessed. Linear regressions between predicted mass flow rate data and experimental measurements were computed, and used them as a statistical comparison criterion. A statistical comparison between predicted simulation results and mass flow rate experimental data are reported. Average deviation errors of ±11.1% (for the refrigerant HFC-407C) and ±7.3% (for refrigerant HFC-410A) were found between numerical model and experimental data. These results demonstrate a new and robust application of the model to predict reliably the mass flow rate through short tube orifices under metastable conditions, which enable this tool to be reliably used for the design of short tube orifices. - Highlights: •A modelling for evaluating short tube orifice was developed for refrigerant mixtures. •The numerical model applied considered metastable regions and choke flow. •The model was validated against experimental data for HFC-407C and HFC-410A. •Statistical analysis based

  3. Whole-brain dynamic CT angiography and perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Orrison, W.W. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Department of Medical Education, University of Nevada School of Medicine, Reno, NV (United States); Snyder, K.V.; Hopkins, L.N. [Department of Neurosurgery, Millard Fillmore Gates Circle Hospital, Buffalo, NY (United States); Roach, C.J. [School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Ringdahl, E.N. [Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV (United States); Nazir, R. [Shifa International Hospital, Islamabad (Pakistan); Hanson, E.H., E-mail: eric.hanson@amigenics.co [College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States)

    2011-06-15

    The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

  4. Simultaneous Multiagent Hyperpolarized 13C Perfusion Imaging

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Bok, Robert A.; Reed, Galen D.

    2014-01-01

    in simulations. "Tripolarized" perfusion MRI methods were applied to initial preclinical studies with differential conditions of vascular permeability, in normal mouse tissues and advanced transgenic mouse prostate tumors. Results: Dynamic imaging revealed clear differences among the individual tracer...... distributions. Computed permeability maps demonstrated differential permeability of brain tissue among the tracers, and tumor perfusion and permeability were both elevated over values expected for normal tissues. Conclusion: Tripolarized perfusion MRI provides new molecular imaging measures for specifically...

  5. Ex vivo perfusion of human spleens maintains clearing and processing functions.

    Science.gov (United States)

    Buffet, Pierre A; Milon, Geneviève; Brousse, Valentine; Correas, Jean-Michel; Dousset, Bertrand; Couvelard, Anne; Kianmanesh, Reza; Farges, Olivier; Sauvanet, Alain; Paye, François; Ungeheuer, Marie-Noëlle; Ottone, Catherine; Khun, Huot; Fiette, Laurence; Guigon, Ghislaine; Huerre, Michel; Mercereau-Puijalon, Odile; David, Peter H

    2006-05-01

    The spleen plays a central role in the pathophysiology of several potentially severe diseases such as inherited red cell membrane disorders, hemolytic anemias, and malaria. Research on these diseases is hampered by ethical constraints that limit human spleen tissue explorations. We identified a surgical situation--left splenopancreatectomy for benign pancreas tumors--allowing spleen retrieval at no risk for patients. Ex vivo perfusion of retrieved intact spleens for 4 to 6 hours maintained a preserved parenchymal structure, vascular flow, and metabolic activity. Function preservation was assessed by testing the ability of isolated-perfused spleens to retain Plasmodium falciparum-infected erythrocytes preexposed to the antimalarial drug artesunate (Art-iRBCs). More than 95% of Art-iRBCs were cleared from the perfusate in 2 hours. At each transit through isolated-perfused spleens, parasite remnants were removed from 0.2% to 0.23% of Art-iRBCs, a proportion consistent with the 0.02% to 1% pitting rate previously established in artesunate-treated patients. Histologic analysis showed that more than 90% of Art-iRBCs were retained and processed in the red pulp, providing the first direct evidence of a zone-dependent parasite clearance by the human spleen. Human-specific physiologic or pathophysiologic mechanisms involving clearing or processing functions of the spleen can now be experimentally explored in a human tissue context.

  6. Myocardial perfusion in patients with left bundle branch block and without coronary artery disease

    International Nuclear Information System (INIS)

    Narita, Michihiro; Kurihara, Tadashi; Murano, Kenichi; Usami, Masahisa; Honda, Minoru

    1992-01-01

    For the evaluation of myocardial perfusion in patients with left bundle branch block (LBBB), we performed exercise stress (Ex)-redistribution (RD) myocardial tomography with thallium-201 ( 201 Tl) in 23 patients with LBBB and without coronary artery disease (CAD). Myocardial images in patients with LBBB were compared with those of 9 patients with CAD who showed Ex induced transient septal defect. Bull'-eye maps ( 201 Tl distribution maps at Ex and RD and 201 Tl washout rate [WOR] map) were made from myocardial tomograms. In 23 patients with LBBB, 15 patients (65%) developed myocardial perfusion abnormality. In 10 (67%) of these 15 patients, transient perfusion defect appeared in the entire septum (diffuse type). On the other hand in 5 patients (33%), localized fixed perfusion defect developed at the boundary between septum and anterior wall (focal type). In focal type, every patient had other disease such as hypertension, aortic stenosis or sick sinus syndrome. While in patients with diffuse type, other diseases were observed in 30% (p 201 Tl WOR and 201 Tl uptake ratio of septum to lateral wall indicated that exercise induced septal defect was slighter in diffuse type than CAD. These points might be useful to differentiate whether CAD participates in the septal defect or not in patients with LBBB. (author)

  7. Pulmonary perfusion scintigraphy in the evaluation of the severity of bronchopulmonary dysplasia

    Energy Technology Data Exchange (ETDEWEB)

    Soler, C. [Neonatal Unit, Dept. of Pediatrics, Casa Maternitat Hospital, Clinical Hospital and Sant Joan de Deu Hospital, Univ. of Barcelona (Spain); Figueras, J. [Neonatal Unit, Dept. of Pediatrics, Casa Maternitat Hospital, Clinical Hospital and Sant Joan de Deu Hospital, Univ. of Barcelona (Spain)]|[Servicio de Neonatologia, Hospital Clinico, Barcelona (Spain); Roca, I. [Nuclear Medicine Unit, Autonomous Univ. of Barcelona (Spain); Perez, J.M. [Neonatal Unit, Dept. of Pediatrics, Casa Maternitat Hospital, Clinical Hospital and Sant Joan de Deu Hospital, Univ. of Barcelona (Spain); Jimenez, R. [Neonatal Unit, Dept. of Pediatrics, Casa Maternitat Hospital, Clinical Hospital and Sant Joan de Deu Hospital, Univ. of Barcelona (Spain)

    1997-01-01

    Objective. The objectives of this study were to analyze the changes in pulmonary perfusion in bronchopulmonary dysplasia (BPD) and to assess the advantages of this method in evaluating the severity of BPD. Patients and methods. The study group was made up of 10 children with BPD, matched with a control group of 12 children. The criteria for matching were birth weight, gestational age and need for ventilation for more than 3 days. Clinical and roentgenographic scoring systems were applied on the 21st day of life. At 6 months of corrected age, clinical evolutive severity was evaluated and a pulmonary perfusion scintigraphy using technetium-99 was performed in each child. The scintigraphic findings were classified in five categories ranging from normal to severely affected, depending on the degree and localization of perfusion abnormalities. Another score was obtained by assigning a value from 1 to 5 to each pulmonary lobe, depending on the concentration of the tracer. Results. The study of clinical, roentgenographic and evolutive scores always showed higher values in children with BPD, with good correlation between methods (P < 0.001). In the BPD group, abnormal lung perfusion patterns were more frequent and more severe (P < 0.05), the lobe scoring was higher (P < 0.05), and a lower count rate was found (P < 0.01). Conclusion. Pulmonary scintigraphy is a useful technique in evaluating the severity of BPD. (orig.). With 1 fig., 3 tabs.

  8. The impact of exercise myocardial perfusion SPECT imaging on the selection of patients for coronary angiography

    International Nuclear Information System (INIS)

    Song Liping; He Zuoxiang; Liu Xiujie; Shi Rongfang; Liu Yunzhong; Tian Yueqin; Zhang Xiaoli; Qin Xuewen; Chen Jilin; Gao Runlin

    2001-01-01

    Objective: Exercise 99 Tc m -MIBI myocardial perfusion SPECT is accurate for the diagnosis of coronary artery disease (CAD). This study assessed the impact of exercise myocardial perfusion imaging on the selection of patients for coronary angiography. Methods: 2188 consecutive patients who underwent exercise myocardial perfusion SPECT in authors' department in 1999 were retrospectively analyzed. Among them, 1807 were men, 381 women (average age: 53.5 +- 7.2 years). Overall, exercise myocardial SPECT was normal in 1731 patients, abnormal in 359 cases, and equivocal in 98 patients. There were 141 patients who underwent CAG within 60 days after myocardial SPECT. Results: Overall, 12% of the patients with abnormal SPECT imaging underwent coronary angiography, but only 5% of the patients with a normal SPECT imaging did (P < 0.001). Among these 141 patients who underwent coronary angiography, significant coronary stenosis was present in 91% of the patients who had had an abnormal SPECT imaging, but only 8% of those who had had a normal SPECT imaging (P < 0.001). In those patients who underwent coronary angiography, revascularization rate was 25% for the patients with abnormal SPECT imaging, but only 1% for the patients with a normal SPECT imaging. Conclusion: The results of exercise myocardial perfusion SPECT have a significant impact on the selection of patients for coronary angiography and revascularization

  9. Pulmonary perfusion scintigraphy in the evaluation of the severity of bronchopulmonary dysplasia

    International Nuclear Information System (INIS)

    Soler, C.; Figueras, J.; Roca, I.; Perez, J.M.; Jimenez, R.

    1997-01-01

    Objective. The objectives of this study were to analyze the changes in pulmonary perfusion in bronchopulmonary dysplasia (BPD) and to assess the advantages of this method in evaluating the severity of BPD. Patients and methods. The study group was made up of 10 children with BPD, matched with a control group of 12 children. The criteria for matching were birth weight, gestational age and need for ventilation for more than 3 days. Clinical and roentgenographic scoring systems were applied on the 21st day of life. At 6 months of corrected age, clinical evolutive severity was evaluated and a pulmonary perfusion scintigraphy using technetium-99 was performed in each child. The scintigraphic findings were classified in five categories ranging from normal to severely affected, depending on the degree and localization of perfusion abnormalities. Another score was obtained by assigning a value from 1 to 5 to each pulmonary lobe, depending on the concentration of the tracer. Results. The study of clinical, roentgenographic and evolutive scores always showed higher values in children with BPD, with good correlation between methods (P < 0.001). In the BPD group, abnormal lung perfusion patterns were more frequent and more severe (P < 0.05), the lobe scoring was higher (P < 0.05), and a lower count rate was found (P < 0.01). Conclusion. Pulmonary scintigraphy is a useful technique in evaluating the severity of BPD. (orig.). With 1 fig., 3 tabs

  10. Assessment of the myocardial perfusion pattern in patients with multivessel coronary artery disease

    International Nuclear Information System (INIS)

    Iskandrian, A.S.; Hakki, A.H.; Segal, B.L.; Kane, S.A.; Amenta, A.

    1983-01-01

    A total of 42 symptomatic patients with coronary artery disease involving two or three vessels were studied using exercise thallium-201 myocardial scintigraphy. Qualitative analysis of the images predicted multivessel disease in 75% of the patients with two-vessel disease and in 82% of the patients with three-vessel disease. Quantitative analysis of the size of the perfusion defect indicated that approximately 40% of the left ventricular perimeter showed abnormal perfusion pattern during stress in these patients, and there was no significant difference in the size of the defect in patients with two-vessel disease or three-vessel disease (41 +/- 17% vs 42 +/- 14%, respectively, mean +/- SD). The exercise heart rate, exercise ECG response, and severity of narrowing did not correlate with the size of the perfusion defect. Patients with anterior infarction had larger defects in the distribution of the left anterior descending artery than those without infarction. Collaterals offered partial protection during exercise only when they were not jeopardized. This study confirms the value of qualitative analysis of exercise thallium-201 imaging in predicting multivessel disease, and describes a simple method of assessing the extent of perfusion abnormalities during stress in patients with multivessel disease. The results may be important in patient management and prognosis

  11. In vivo perfusion assessment of an anastomosis surgery on porcine intestinal model (Conference Presentation)

    Science.gov (United States)

    Le, Hanh N. D.; Opferman, Justin; Decker, Ryan; Cheon, Gyeong W.; Kim, Peter C. W.; Kang, Jin U.; Krieger, Axel

    2016-04-01

    Anastomosis, the connection of two structures, is a critical procedure for reconstructive surgery with over 1 million cases/year for visceral indication alone. However, complication rates such as strictures and leakage affect up to 19% of cases for colorectal anastomoses and up to 30% for visceral transplantation anastomoses. Local ischemia plays a critical role in anastomotic complications, making blood perfusion an important indicator for tissue health and predictor for healing following anastomosis. In this work, we apply a real time multispectral imaging technique to monitor impact on tissue perfusion due to varying interrupted suture spacing and suture tensions. Multispectral tissue images at 470, 540, 560, 580, 670 and 760 nm are analyzed in conjunction with an empirical model based on diffuse reflectance process to quantify the hemoglobin oxygen saturation within the suture site. The investigated tissues for anastomoses include porcine small (jejunum and ileum) and large (transverse colon) intestines. Two experiments using interrupted suturing with suture spacing of 1, 2, and 3 mm and tension levels from 0 N to 2.5 N are conducted. Tissue perfusion at 5, 10, 20 and 30 min after suturing are recorded and compared with the initial normal state. The result indicates the contrast between healthy and ischemic tissue areas and assists the determination of suturing spacing and tension. Therefore, the assessment of tissue perfusion will permit the development and intra-surgical monitoring of an optimal suture protocol during anastomosis with less complications and improved functional outcome.

  12. Vascular perfusion of reproductive organs in pony mares and heifers during sedation with detomidine or xylazine.

    Science.gov (United States)

    Araujo, Reno R; Ginther, O J

    2009-01-01

    To assess the vascular effects of detomidine and xylazine in pony mares and heifers, respectively, as determined in a major artery and by extent of vascular perfusion of reproductive organs. 10 pony mares and 10 Holstein heifers. Pony mares were assigned to receive physiologic saline (0.9% NaCl) solution (n = 5) or detomidine (3.0 mg/mare, IV; 5). Heifers were assigned to receive saline solution (5) or xylazine (14 mg/heifer, IM; 5). Color Doppler ultrasonographic examinations were performed immediately before and 10 minutes after administration of saline solution or sedative. In spectral Doppler mode, a spectral graph of blood flow velocities during a cardiac cycle was obtained at the internal iliac artery and at the ovarian pedicle. In color-flow mode, color signals of blood flow in vessels of the corpus luteum and endometrium were assessed. Systemic effects of sedation in the 2 species were evident as a decrease in heart rate; increase in duration of systole, diastole, or both; decrease in volume of blood flow; and decrease in velocity of blood flow within the internal iliac artery. However, an effect of sedatives on local vascular perfusion in the ovaries and endometrium was not detected. Sedation with detomidine in pony mares and xylazine in heifers did not affect vascular perfusion in reproductive organs. These sedatives can be used in experimental and clinical color Doppler evaluations of vascular perfusion of the corpus luteum and endometrium.

  13. Characteristics of myocardial perfusion imaging and coronary artery angiography in patients of NIDDM complicated with AMI

    International Nuclear Information System (INIS)

    Zhao Peiqin; Zhao Jinhua; Qin Mingzhao; Dai HaoJie; Zhang Runwu; Xiao Fen

    2001-01-01

    Objective: To investigate the characteristic changes of myocardial perfusion imaging and coronary artery angiography in patients of acute myocardial infarction (AMI) with underlined type 2 diabetes mellitus. Methods: 25 type 2 diabetes mellitus patients were enrolled for having clinical manifestation of AMI. Ten inpatients with AMI of simple coronary heart disease origin were served as controls. All subjects underwent both myocardial perfusion imagings (resting and nitroglycerine invention) and coronary artery angiography. Results: Compared to controls (40%), type 2 diabetes mellitus + AMI group had higher rate of multivessel disease (60%). For type 2 diabetes mellitus + AMI patients, 129/400 segments (32.25%) showed fixed defect, 25/160 segments (15.62%) in controls. Conclusions: For type 2 diabetes mellitus + AMI group, myocardial perfusion defects are widely distributed and multivessel or severe stenosis is more often presented. Good correlation exists between abnormal segments and angiographic lesions in both the number of segments involved and the severity of the lesions. Radionuclide myocardial perfusion is therefore considered a useful screening test not inferior to angiography, especially for those who are not tolerant enough to undergoing angiography

  14. Impaired glymphatic perfusion after strokes revealed by contrast-enhanced MRI: a new target for fibrinolysis?

    Science.gov (United States)

    Gaberel, Thomas; Gakuba, Clement; Goulay, Romain; Martinez De Lizarrondo, Sara; Hanouz, Jean-Luc; Emery, Evelyne; Touze, Emmanuel; Vivien, Denis; Gauberti, Maxime

    2014-10-01

    The aim of the present study was to investigate the impact of different stroke subtypes on the glymphatic system using MRI. We first improved and characterized an in vivo protocol to measure the perfusion of the glymphatic system using MRI after minimally invasive injection of a gadolinium chelate within the cisterna magna. Then, the integrity of the glymphatic system was evaluated in 4 stroke models in mice including subarachnoid hemorrhage (SAH), intracerebral hemorrhage, carotid ligature, and embolic ischemic stroke. We were able to reliably evaluate the glymphatic system function using MRI. Moreover, we provided evidence that the glymphatic system was severely impaired after SAH and in the acute phase of ischemic stroke, but was not altered after carotid ligature or in case of intracerebral hemorrhage. Notably, this alteration in glymphatic perfusion reduced brain clearance rate of low-molecular-weight compounds. Interestingly, glymphatic perfusion after SAH can be improved by intracerebroventricular injection of tissue-type plasminogen activator. Moreover, spontaneous arterial recanalization was associated with restoration of the glymphatic function after embolic ischemic stroke. SAH and acute ischemic stroke significantly impair the glymphatic system perfusion. In these contexts, injection of tissue-type plasminogen activator either intracerebroventricularly to clear perivascular spaces (for SAH) or intravenously to restore arterial patency (for ischemic stroke) may improve glymphatic function. © 2014 American Heart Association, Inc.

  15. Perfusion single photon emission computed tomography of myocardium with 99mTc-tetra-phosmine (Myoview)

    International Nuclear Information System (INIS)

    Khusainova, Sh.K.; Zholdybaj, Zh.; Potapov, A.V.; Karaev, O.S.; Akhmetova, G.R.

    2003-01-01

    The aim of the work is study of diagnostic valuation of myocardium scintigraphy with help of the 99m Tc-tetrophosmin, Myoview in determination of latent coronary blood-circulation destabilization in liquidators of the Chernobyl accident (LChA) and persons living in the Semipalatinsk test site (STS) region. The perfusion myocardium scintigraphy was made to 71 patients (5 women and 66 men) from those - 33 LChA and 37 - residents of STS region. The examination was carried out in 'ADAC Genesys Epic' apparatus (USA). Mean age of the patients was 46.3±2.3 years old. In the result of examination the left ventricle myocardium perfusion reduction on 30 % and more was revealed. The distribution of radiopharmaceutical by the myocardium parts were relatively proportional both with pharmacologic load (ATF, dipiridamol) and the rest in 48 (67.7 %) patients. So, the 99m Tc-tetrophosmin, Myoview pharmaceutical allows with high rate estimate the myocardium perfusion and get a high qualitative images, that permits to identify localization, character and distribution of myocardium perfusion reduction in the revealed areas. In the result of myocardine scintigraphy with the pharmacologic load trial conducting the both the latent coronary blood-circulation destabilization forms and the incoming ones were differentiated

  16. Autonomic Function Impairment and Brain Perfusion Deficit in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Wei-Che Lin

    2017-06-01

    Full Text Available IntroductionAutonomic disorders have been recognized as important Parkinson’s disease (PD components. Some vulnerable structures are related to the central autonomic network and have also been linked to autonomic function alterations. The aims of the study are to evaluate the severity of the autonomic dysfunction and the cortical hypoperfusion using arterial spin labeling (ASL MRI. And then, possible relationships of significant between-group differences in perfusion pattern to clinical variables and autonomic functions were examined to determine the pharmaceutical effects of dopaminergic treatment on cerebral blood flow (CBF in patients with PD.MethodsBrain ASL MRI was carried out in 20 patients with PD (6 men and 14 women, mean age: 63.3 ± 6.4 years and 22 sex- and age-matched healthy volunteers to assess whole-brain CBF and the effects of dopaminergic therapy on perfusion. All subjects underwent a standardized evaluation of cardiovagal and adrenergic function including a deep breathing, Valsalva maneuver, and 5-min head-up tilt test. Perfusion MRI data were acquired on a 3.0 T scanner with a pulsed continuous ASL technique. The CBF, autonomic parameters, and clinical data were analyzed after adjusting for age and sex.ResultsPatients exhibited a decline in autonomic function (rapid heart rate in response to deep breathing, low baroreflex sensitivity, high systolic and diastolic pressure, and altered tilting test response, widespread low CBF, and robust response to dopaminergic therapy. Lower perfusion in the middle frontal gyrus was associated with increased clinical disease severity (Unified Parkinson’s Disease Rating Scale I score, P < 0.001. Lower perfusion in autonomic control areas, such as the frontal lobe and insula, were significantly associated with autonomic impairment (P < 0.001.ConclusionsOur study indicates that PD is a progressive neurodegenerative disorder that changes the perfusion of central nervous system

  17. Assessing tumor treatment response and prognosis in non-small cell lung cancer with perfusion CT

    International Nuclear Information System (INIS)

    Wang Jianwei; Wu Ning; Song Ying

    2010-01-01

    Objective: To prospectively investigate whether any of the perfusion parameters would predict early tumor response to chemotherapy and/or radiotherapy and prognosis in non-small cell lung cancer (NSCLC). Methods: In a prospective series, Perfusion CT were performed in 152 patients suspected lung cancer with 16-slice or 8-slice multislice CT. Contrast medium (50 ml) was injected at a rate of 4 ml/s with a power injector. The scanning delay was 10 seconds and the scanning time was 50 seconds. Among 152 patients, 123 patients were proved lung cancer by pathology. With the perfusion 3.0 software, the parameters including blood flow (BF), blood volume (BV), mean transit time (MTT) and capillary permeability surface area product (PS) were calculated. The perfusion image quality was evaluated on a 4-1eveal scale. The treatment response after chemotherapy and (or) radiotherapy was assessed with Response Evaluation Criteria in Solid Tumors (RECIST), and then the relationship between perfusion parameters with early tumor response to chemotherapy and (or) radiotherapy was evaluated. Student t test and Kaplan-Meier estimates were used for data analysis. Results: In 84 patients (68.3%), the perfusion image quality was staged level 2 (moderate) and level 3 (good). Among them, 35 patients with NSCLC were assessed with RECIST after chemotherapy and (or) radiotherapy. In these 35 patients, The BF of responders and nonresponders was (81.0 ± 33.6)and (56.3 ± 23.1) ml · min -1 ·100 g -1 , respectively, which was significantly different(t=2.393, P=0.023). The median PFS of low-BF group (BF ≤ 80 ml · min -1 · 100 g -1 ) and high-BF group (BF>80 ml · min -1 · 100 g -1 ) was 11.8 and 8.0 months respectively (P>0.05), and the median PFS of low-BV group (BF ≤ 6 ml/100 g -1 ) and high-BV group (BF>6 ml/100 g -1 ) was 9.2 and 8.0 months respectively(P>0.05), both of them were not significantly different. Conclusion: NSCLC in high perfusion are relatively sensitive to chemotherapy

  18. Effect of Defocused CO2 Laser on Equine Tissue Perfusion

    Directory of Open Access Journals (Sweden)

    Bergh A

    2006-03-01

    Full Text Available Treatment with defocused CO2 laser can have a therapeutic effect on equine injuries, but the mechanisms involved are unclear. A recent study has shown that laser causes an increase in equine superficial tissue temperature, which may result in an increase in blood perfusion and a stimulating effect on tissue regeneration. However, no studies have described the effects on equine tissue perfusion. The aim of the present study was to investigate the effect of defocused CO2 laser on blood perfusion and to correlate it with temperature in skin and underlying muscle in anaesthetized horses. Differences between clipped and unclipped haircoat were also assessed. Eight horses and two controls received CO2 laser treatment (91 J/cm2 in a randomised order, on a clipped and unclipped area of the hamstring muscles, respectively. The significant increase in clipped skin perfusion and temperature was on average 146.3 ± 33.4 perfusion units (334% and 5.5 ± 1.5°C, respectively. The significant increase in perfusion and temperature in unclipped skin were 80.6 ± 20.4 perfusion units (264% and 4.8 ± 1.4°C. No significant changes were seen in muscle perfusion or temperature. In conclusion, treatment with defocused CO2 laser causes a significant increase in skin perfusion, which is correlated to an increase in skin temperature.

  19. Perfusion lung scanning: differentiation of primary from thromboembolic pulmonary hypertension

    International Nuclear Information System (INIS)

    Lisbona, R.; Kreisman, H.; Novales-Diaz, J.; Derbekyan, V.

    1985-01-01

    Of eight patients with pulmonary arterial hypertension, final diagnosis established by autopsy or angiography, four had primary hypertension and four hypertension from thromboembolism. The perfusion lung scan was distinctly different in the two groups. The lung scan in primary pulmonary hypertension was associated with nonsegmental, patchy defects of perfusion, while in thromboembolic hypertensives it was characterized by segmental and/or lobar defects of perfusion with or without subsegmental defects. The perfusion lung scan is a valuable, noninvasive study in the evaluation of the patient with pulmonary hypertension of undetermined cause and in the exclusion of occult large-vessel pulmonary thromboembolism

  20. Amniotic fluid embolism

    Directory of Open Access Journals (Sweden)

    Kiranpreet Kaur

    2016-01-01

    Full Text Available Amniotic fluid embolism (AFE is one of the catastrophic complications of pregnancy in which amniotic fluid, fetal cells, hair, or other debris enters into the maternal pulmonary circulation, causing cardiovascular collapse. Etiology largely remains unknown, but may occur in healthy women during labour, during cesarean section, after abnormal vaginal delivery, or during the second trimester of pregnancy. It may also occur up to 48 hours post-delivery. It can also occur during abortion, after abdominal trauma, and during amnio-infusion. The pathophysiology of AFE is not completely understood. Possible historical cause is that any breach of the barrier between maternal blood and amniotic fluid forces the entry of amniotic fluid into the systemic circulation and results in a physical obstruction of the pulmonary circulation. The presenting signs and symptoms of AFE involve many organ systems. Clinical signs and symptoms are acute dyspnea, cough, hypotension, cyanosis, fetal bradycardia, encephalopathy, acute pulmonary hypertension, coagulopathy etc. Besides basic investigations lung scan, serum tryptase levels, serum levels of C3 and C4 complements, zinc coproporphyrin, serum sialyl Tn etc are helpful in establishing the diagnosis. Treatment is mainly supportive, but exchange transfusion, extracorporeal membrane oxygenation, and uterine artery embolization have been tried from time to time. The maternal prognosis after amniotic fluid embolism is very poor though infant survival rate is around 70%.

  1. Characterization of local fluid flow in 3D porous construct characterized by Fourier domain Doppler optical coherence tomography

    Science.gov (United States)

    Bagnaninchi, P. O.; Yang, Y.; El Haj, A.; Hinds, M. T.; Wang, R. K.

    2007-02-01

    In order to achieve functional tissue with the correct biomechanical properties it is critical to stimulate mechanically the cells. Perfusion bioreactor induces fluid shear stress that has been well characterized for two-dimensional culture where both simulation and experimental data are available. However these results can't be directly translated to tissue engineering that makes use of complex three-dimensional porous scaffold. Moreover, stimulated cells produce extensive extra-cellular matrix (ECM) that alter dramatically the micro-architecture of the constructs, changing the local flow dynamic. In this study a Fourier domain Doppler optical coherent tomography (FD-DOCT) system working at 1300nm with a bandwidth of 50nm has been used to determine the local flow rate inside different types of porous scaffolds used in tissue engineering. Local flow rates can then be linearly related, for Newtonian fluid, to the fluid shear stress occurring on the pores wall. Porous chitosan scaffolds (\\fgr 1.5mm x 3mm) with and without a central 250 μm microchannel have been produced by a freeze-drying technique. This techniques allow us to determine the actual shear stress applied to the cells and to optimise the input flow rate consequently, but also to relate the change of the flow distribution to the amount of ECM production allowing the monitoring of tissue formation.

  2. The clinical application value of myocardial perfusion imaging in evaluating coronary artery myocardial bridge patients with symptoms

    International Nuclear Information System (INIS)

    Wang Yuetao; Fu Ning; Ding Xuemei; Lu Cunzhi; Zhu Feng; Wang Guanmin; Huang Yijie; Wang Linguang

    2008-01-01

    ischemia. The mean angio- graphic systolic occlusion within the myocardial bridge was significantly higher in patients with myocardial ischemia on myocardial perfusion imaging than in those with normal myocardial perfusion imaging [(78.0 ± 4.7)% vs (52.8 ± 6.7)%, t=3.06, P 0.05]. Conclusion: 99 Tc m -MIBI myocardial perfusion imaging had higher detection rate of myocardial bridging than movement ECG in symptomatic patients. (authors)

  3. Fluid dynamics

    CERN Document Server

    Ruban, Anatoly I

    This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...

  4. [Myocardial perfusion imaging by digital subtraction angiography].

    Science.gov (United States)

    Kadowaki, H; Ishikawa, K; Ogai, T; Katori, R

    1986-03-01

    Several methods of digital subtraction angiography (DSA) were compared to determine which could better visualize regional myocardial perfusion using coronary angiography in seven patients with myocardial infarction, two with angina pectoris and five with normal coronary arteries. Satisfactory DSA was judged to be achieved if the shape of the heart on the mask film was identical to that on the live film and if both films were exactly superimposed. To obtain an identical mask film in the shape of each live film, both films were selected from the following three phases of the cardiac cycle; at the R wave of the electrocardiogram, 100 msec before the R wave, and 200 msec before the R wave. The last two were superior for obtaining mask and live films which were similar in shape, because the cardiac motion in these phases was relatively small. Using these mask and live films, DSA was performed either with the continuous image mode (CI mode) or the time interval difference mode (TID mode). The overall perfusion of contrast medium through the artery to the vein was adequately visualized using the CI mode. Passage of contrast medium through the artery, capillary and vein was visualized at each phase using TID mode. Subtracted images were displayed and photographed, and the density of the contrast medium was adequate to display contour lines as in a relief map. Using this DSA, it was found that regional perfusion of the contrast medium was not always uniform in normal subjects, depending on the typography of the coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. [Myokard-Perfusions-SPECT. Myocardial perfusion SPECT - Update S1 guideline].

    Science.gov (United States)

    Lindner, Oliver; Bengel, Frank; Burchert, Wolfgang; Dörr, Rolf; Hacker, Marcus; Schäfer, Wolfgang; Schäfers, Michael A; Schmidt, Matthias; Schwaiger, Markus; Vom Dahl, Jürgen; Zimmermann, Rainer

    2017-08-14

    The S1 guideline for myocardial perfusion SPECT has been published by the Association of the Scientific Medical Societies in Germany (AWMF) and is valid until 2/2022. This paper is a short summary with comments on all chapters and subchapters wich were modified and amended.

  6. The functional state of perfused liver tissue in X-ray irradiated rats

    International Nuclear Information System (INIS)

    Borovikova, G.V.; Dokshina, G.A.; Lapteva, T.A.

    1981-01-01

    The results of studying the functional state of perfused liver tissue isolated from rates after irradiation in the 18.06x10 - 2 Kl/kg dose, which has been estimated by transamination process rate catalized alanine-(KF 2.6x1.2, ALT and aspartate by aminotransferases (KF 2.6x1.1, ACT), gluconeogenesis and urea production intensity presented. When comparing the results obtained on the perfused liver deprived of homeostatic body effects it has been found that the liver isolated from the body for the first 24 hours of the radiation sickness development possesses a higher radiation activity which manifests itself in intensification of the processes of gluconeogenesis and transamination with substrate addition. The third 24 hours upon irradiation in the isolated liver the intensity of the gluconeogenesis and transamination processes is attenuated

  7. Multiphasic perfusion CT in acute middle cerebral artery ischemic stroke: prediction of final infarct volume and correlation with clinical outcome

    International Nuclear Information System (INIS)

    Yi, Chin A; Na, Dong Gyu; Ryoo, Jae Wook; Moon, Chan Hong; Byun, Hong Sik; Roh, Hong Gee; Moon, Won Jin; Lee, Kwang Ho; Lee, Soo Joo

    2002-01-01

    To assess the utility of multiphasic perfusion CT in the prediction of final infarct volume, and the relationship between lesion volume revealed by CT imaging and clinical outcome in acute ischemic stroke patients who have not undergone thrombolytic therapy. Thirty-five patients underwent multiphasic perfusion CT within six hours of stroke onset. After baseline unenhanced helical CT scanning, contrast-enhanced CT scans were obtained 20, 34, 48, and 62 secs after the injection of 90 mL contrast medium at a rate of 3 mL/sec. CT peak and total perfusion maps were obtained from serial CT images, and the initial lesion volumes revealed by CT were compared with final infarct volumes and clinical scores. Overall, the lesion volumes seen on CT peak perfusion maps correlated most strongly with final infarct volumes (R2=0.819, p<0.001, slope of regression line=1.016), but individual data showed that they were less than final infarct volume in 31.4% of patients. In those who showed early clinical improvement (n=6), final infarct volume tended to be overestimated by CT peak perfusion mapping and only on total perfusion maps was there significant correlation between lesion volume and final infarct volume (R2=0.854, p=0.008). The lesion volumes depicted by CT maps showed moderate correlation with baseline clinical scores and clinical outcomes (R=0.445-0.706, p≤0.007). CT peak perfusion maps demonstrate strong correlation between lesion volume and final infarct volume, and accurately predict final infarct volume in about two-thirds of the 35 patients. The lesion volume seen on CT maps shows moderate correlation with clinical outcome

  8. Perfusion magnetic resonance imaging with continuous arterial spin labeling: methods and clinical applications in the central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Detre, John A. E-mail: detre@mail.med.upenn.edu; Alsop, David C

    1999-05-01

    Several methods are now available for measuring cerebral perfusion and related hemodynamic parameters using magnetic resonance imaging (MRI). One class of techniques utilizes electromagnetically labeled arterial blood water as a noninvasive diffusible tracer for blood flow measurements. The electromagnetically labeled tracer has a decay rate of T1, which is sufficiently long to allow perfusion of the tissue and microvasculature to be detected. Alternatively, electromagnetic arterial spin labeling (ASL) may be used to obtain qualitative perfusion contrast for detecting changes in blood flow, similar to the use of susceptibility contrast in blood oxygenation level dependent functional MRI (BOLD fMRI) to detect functional activation in the brain. The ability to obtain blood flow maps using a non-invasive and widely available modality such as MRI should greatly enhance the utility of blood flow measurement as a means of gaining further insight into the broad range of hemodynamically related physiology and pathophysiology. This article describes the biophysical considerations pertaining to the generation of quantitative blood flow maps using a particular form of ASL in which arterial blood water is continuously labeled, termed continuous arterial spin labeling (CASL). Technical advances permit multislice perfusion imaging using CASL with reduced sensitivity to motion and transit time effects. Interpretable cerebral perfusion images can now be reliably obtained in a variety of clinical settings including acute stroke, chronic cerebrovascular disease, degenerative diseases and epilepsy. Over the past several years, the technical and theoretical foundations of CASL perfusion MRI techniques have evolved from feasibility studies into practical usage. Currently existing methodologies are sufficient to make reliable and clinically relevant observations which complement structural assessment using MRI. Future technical improvements should further reduce the acquisition times

  9. Markov-modulated and feedback fluid queues

    NARCIS (Netherlands)

    Scheinhardt, Willem R.W.

    1998-01-01

    In the last twenty years the field of Markov-modulated fluid queues has received considerable attention. In these models a fluid reservoir receives and/or releases fluid at rates which depend on the actual state of a background Markov chain. In the first chapter of this thesis we give a short

  10. 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.

  11. Correlation between melphalan pharmacokinetics and hepatic toxicity following hyperthermic isolated liver perfusion for unresectable metastatic disease.

    Science.gov (United States)

    Mocellin, Simone; Pilati, Pierluigi; Da Pian, Pierpaolo; Forlin, Marco; Corazzina, Susanna; Rossi, Carlo Riccardo; Innocente, Federico; Ori, Carlo; Casara, Dario; Ujka, Francesca; Nitti, Donato; Lise, Mario

    2007-02-01

    In the present work, we report on the results of our pilot study of hyperthermic isolated hepatic perfusion (IHP) with melphalan alone for patients with unresectable metastatic liver tumors refractory to conventional treatments, with particular regard to the correlation between pharmacokinetic findings and hepatic toxicity. Inclusion criteria were unresectable liver metastases, hepatic parenchyma replacement perfusion circuit were assessed by a radiolabeled albumin-based method. Drug concentrations in perfusate and plasma were measured by means of high-performance liquid chromatography (HPLC). Twenty patients with unresectable liver metastases underwent IHP. No intraoperative mortality occurred. Treatment-related systemic toxicity was minimal and reversible. Three patients (15%) experienced grade 4 hepatic toxicity and died due to liver failure and subsequent multiorgan failure. Other six patients had significant (grade 3-4) but transitory hepatic toxicity. Complete and partial responses were observed in three and nine out of 17 evaluable patients, respectively (overall response rate = 70%). The pharmacokinetics study showed a 3% mean perfusate-to-plasma drug leakage (range 1-6%). Logistic regression analysis showed that drug concentration in the perfusate circuit, but not preoperative tests, significantly and independently correlated with hepatic toxicity (P = 0.028). Following melphalan-based IHP, objective tumor regression could be observed in a remarkable percentage of patients refractory to standard treatments. However, hepatic toxicity and related mortality were significant. Our findings suggest that drug dosage personalization based on the measurement of drug distribution volumes might minimize

  12. Perfusion abnormality of the caudate nucleus in patients with paroxysmal kinesigenic choreoathetosis

    International Nuclear Information System (INIS)

    Joo, Eun Yeon; Hong, Seung Bong; Tae, Woo Suk; Kim, Jee Hyun; Han, Sun Jung; Seo, Dae Won; Lee, Kyung-Han; Kim, Byung Tae; Kim, Myoung-Hee; Kim, Seunghwan; Lee, Mann Hyung

    2005-01-01

    Previous cerebral blood flow and glucose metabolism studies suggest that the basal ganglia or thalamus is involved in the pathogenesis of paroxysmal kinesigenic choreoathetosis (PKC). However, the underlying cerebral abnormalities in idiopathic PKC have not been elucidated. To localise cerebral perfusion abnormalities in PKC, we performed interictal brain perfusion 99m Tc-ethylcysteinate dimer (ECD) single-photon emission computed tomography (SPECT) in PKC patients and in normal controls. Sixteen patients with idiopathic PKC and 18 age- and sex-matched normal controls were included. The patients were de novo diagnosed as having PKC, or had not taken medication for at least 3 months; none of them had structural abnormalities on MRI. Patients had a history of PKC attacks of a duration not exceeding 5 min and starting either on one side or on both sides of the body. These attacks were always induced by a sudden initiation of voluntary movement. PKC attacks were recorded in a hospital after being induced by neurology staff in 13 of the 16 patients. Interictal brain perfusion 99m Tc-ECD SPECT was performed in all 16 patients and 18 normal controls. Differences between the cerebral perfusion in the PKC group and the normal control group were tested by statistical parametric mapping. Student's t test was used for inter-group comparisons. Compared with normal controls, patients with idiopathic PKC showed interictal hypoperfusion in the posterior regions of the bilateral caudate nuclei (false discovery rate-corrected P<0.001 with a small volume correction). This study showed that cerebral perfusion abnormality of bilateral caudate nuclei is present in idiopathic PKC. (orig.)

  13. Perfusion computed tomography for detection of hepatocellular carcinoma in patients with liver cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Michael A.; Kartalis, Nikolaos; Grigoriadis, Aristeidis; Loizou, Louiza; Leidner, Bertil; Aspelin, Peter; Brismar, Torkel B. [Karolinska Institute, Department of Clinical Science, Intervention and Technology, Division of Medical Imaging and Technology, Stockholm (Sweden); Karolinska University Hospital, Department of Radiology, Stockholm (Sweden); Staal, Per [Karolinska University Hospital, Department of Hepatology, Stockholm (Sweden)

    2015-11-15

    To evaluate the diagnostic performance of dynamic perfusion CT (P-CT) for detection of hepatocellular carcinoma (HCC) in the cirrhotic liver. Twenty-six cirrhotic patients (19 men, aged 69 ± 10 years) with suspicion of HCC prospectively underwent P-CT of the liver using the 4D spiral-mode (100/80 kV; 150/175mAs/rot) of a dual-source system. Two readers assessed: (1) arterial liver-perfusion (ALP), portal-venous liver-perfusion (PLP) and hepatic perfusion-index (HPI) maps alone; and (2) side-by-side with maximum-intensity-projections of arterial time-points (art-MIP) for detection of HCC using histopathology and imaging follow-up as standard of reference. Another reader quantitatively assessed perfusion maps of detected lesions. A total of 48 HCCs in 21/26 (81 %) patients with a mean size of 20 ± 10 mm were detected by histopathology (9/48, 19 %) or imaging follow-up (39/48, 81 %). Detection rates (Reader1/Reader2) of HPI maps and side-by-side analysis of HPI combined with arterial MIP were 92/88 % and 98/96 %, respectively. Positive-predictive values were 63/63 % and 68/71 %, respectively. A cut-off value of ≥85 % HPI and ≥99 % HPI yielded a sensitivity and specificity of 100 %, respectively, for detection of HCC. P-CT shows a high sensitivity for detection of HCC in the cirrhotic liver. Quantitative assessment has the potential to reduce false-positive findings improving the specificity of HCC diagnosis. (orig.)

  14. Perfusion abnormality of the caudate nucleus in patients with paroxysmal kinesigenic choreoathetosis

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Eun Yeon; Hong, Seung Bong; Tae, Woo Suk; Kim, Jee Hyun; Han, Sun Jung; Seo, Dae Won [Sungkyunkwan University School of Medicine, Department of Neurology, Samsung Medical Center and Center for Clinical Medicine, SBRI, Seoul (Korea); Lee, Kyung-Han; Kim, Byung Tae [Sungkyunkwan University School of Medicine, Department of Nuclear Medicine, Samsung Medical Center and Center for Clinical Medicine, SBRI, Seoul (Korea); Kim, Myoung-Hee [Ewha Women' s University, Department of Computer Science and Engineering, Seoul (Korea); Kim, Seunghwan [POSTECH, APCTP/NCSL, Department of Physics, Pohang (Korea); Lee, Mann Hyung [Catholic University of Daegue, College of Pharmacy, Gyongbook (Korea)

    2005-10-01

    Previous cerebral blood flow and glucose metabolism studies suggest that the basal ganglia or thalamus is involved in the pathogenesis of paroxysmal kinesigenic choreoathetosis (PKC). However, the underlying cerebral abnormalities in idiopathic PKC have not been elucidated. To localise cerebral perfusion abnormalities in PKC, we performed interictal brain perfusion {sup 99m}Tc-ethylcysteinate dimer (ECD) single-photon emission computed tomography (SPECT) in PKC patients and in normal controls. Sixteen patients with idiopathic PKC and 18 age- and sex-matched normal controls were included. The patients were de novo diagnosed as having PKC, or had not taken medication for at least 3 months; none of them had structural abnormalities on MRI. Patients had a history of PKC attacks of a duration not exceeding 5 min and starting either on one side or on both sides of the body. These attacks were always induced by a sudden initiation of voluntary movement. PKC attacks were recorded in a hospital after being induced by neurology staff in 13 of the 16 patients. Interictal brain perfusion {sup 99m}Tc-ECD SPECT was performed in all 16 patients and 18 normal controls. Differences between the cerebral perfusion in the PKC group and the normal control group were tested by statistical parametric mapping. Student's t test was used for inter-group comparisons. Compared with normal controls, patients with idiopathic PKC showed interictal hypoperfusion in the posterior regions of the bilateral caudate nuclei (false discovery rate-corrected P<0.001 with a small volume correction). This study showed that cerebral perfusion abnormality of bilateral caudate nuclei is present in idiopathic PKC. (orig.)

  15. Paradoxical hypotension during dobutamine infusion for myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Erguen, E.L.; Caner, B.; Atalar, E.; Karanfil, A.; Tokgoezoglu, L.

    1998-01-01

    Dobutamine as a predominant beta-1 agonist increases heart rate and myocardial contractility and at sufficient high doses, it also increases systolic blood pressure. This study was undertaken to describe instances of paradoxical hypotension during dobutamine infusion for Tl-201 myocardial perfusion SPECT study and the relationship between scintigraphic findings and hypotension occurred during dobutamine infusion. Methods: In 201 consecutive patients unable to perform adequate exercise, dobutamine Tl-201 myocardial SPECT was performed. Dobutamine was infused starting from 10 μg/kg/min increasing to 40 μ/kg/min. Paradoxical hypotension was defined as a decrease in systolic blood pressure ≥ 20 mmHg compared with baseline study. Paradoxical hypotension was observed in 40 patients (Group A) out of 201 (19.9%) while no significant change in systolic blood pressure was detected in the remaining 161 patients (Group B). Mean maximum fall in systolic blood pressure was 39±18 mmHg (range: 20-90). In 33 of 40 patients (83%) with paradoxical hypotension, scintigraphy was normal compared to 131 (81%) of the remaining 161 patients. In patients of Group A, angiography, echocardiography and tilt table tests were performed in 13, 11 and 6 patients respectively. Nine of 13 angiographic evaluations (69%), 10 of 11 echocardiographic evaluations (91%), all of the tilt table tests were normal. Additionally, all of the patients of Group A were clinically followed up at least 6 months after the myocardial perfusion scintigraphy. None of the patients had a cardiac event except one patient during the follow-up period. Conclusion: Paradoxical hypotension during dobutamine infusion for myocardial scintigraphy is not an uncommon finding and up to 19.9% patients may develop such hypotension. To maximize test safety, precautions should be taken during dobutamine myocardial stress test, since remarkable decrease in systolic blood pressure may occur. Unlike hypotension occurring with exercise

  16. Computed Tomography Perfusion Usefulness in Early Imaging Diagnosis of Herpes Simplex Virus Encephalitis

    International Nuclear Information System (INIS)

    Marco de Lucas, E.; Mandly, Gonzalez A.; Gutierrez, A.; Sanchez, E.; Arnaiz, J.; Piedra, T.; Rodriguez, E.; Diez, C.

    2006-01-01

    An early diagnosis is crucial in herpes simplex virus encephalitis patients in order to institute acyclovir therapy and reduce mortality rates. Magnetic resonance imaging (MRI) is considered the gold standard for evaluation of these patients, but is frequently not available in the emergency setting. We report the first case of a computed tomography (CT) perfusion study that helped to establish a prompt diagnosis revealing abnormal increase of blood flow in the affected temporoparietal cortex at an early stage

  17. Diffusion and perfusion imaging of bone marrow

    International Nuclear Information System (INIS)

    Biffar, Andreas; Dietrich, Olaf; Sourbron, Steven; Duerr, Hans-Roland; Reiser, Maximilian F.; Baur-Melnyk, Andrea

    2010-01-01

    In diffusion-weighted magnetic resonance imaging (DWI), the observed MRI signal intensity is attenuated by the self-diffusion of water molecules. DWI provides information about the microscopic structure and organization of a biological tissue, since the extent and orientation of molecular motion is influenced by these tissue properties. The most common method to measure perfusion in the body using MRI is T1-weighted dynamic contrast enhancement (DCE-MRI). The analysis of DCE-MRI data allows determining the perfusion and permeability of a biological tissue. DWI as well as DCE-MRI are established techniques in MRI of the brain, while significantly fewer studies have been published in body imaging. In recent years, both techniques have been applied successfully in healthy bone marrow as well as for the characterization of bone marrow alterations or lesions; e.g., DWI has been used in particular for the differentiation of benign and malignant vertebral compression fractures. In this review article, firstly a short introduction to diffusion-weighted and dynamic contrast-enhanced MRI is given. Non-quantitative and quantitative approaches for the analysis of DWI and semiquantitative and quantitative approaches for the analysis of DCE-MRI are introduced. Afterwards a detailed overview of the results of both techniques in healthy bone marrow and their applications for the diagnosis of various bone-marrow pathologies, like osteoporosis, bone tumors, and vertebral compression fractures are described.

  18. Brain perfusion imaging with iodinated amines

    International Nuclear Information System (INIS)

    Kung, H.F.

    1989-01-01

    Traditional nuclear medicine brain study using 99m Tc pertechnetate, glucoheptonate or diethlenetriaminepentacetic acid (DTPA) and planar imaging has experienced a significant decline in the past 10 years. This is mainly due to the introduction of X-ray CT and more recently the nuclear magnetic resonance (NMR) imaging, by which detailed morphology of the brain, including the detection of breakdown of the blood-brain barrier, can be obtained. The nuclear medicine brain imaging is only prescribed as a complementary test when X-ray CT is negative or equivocal and clinical suspicion remains. The attention of nuclear medicine brain imaging has been shifted from the detection of the breakdown of the blood-brain barrier to the study of brain function-perfusion, metabolism, and receptor binding, etc. The functional brain imaging provides diagnostic information usually unattainable by other radiological techniques. In this article, the iodinated amines as brain perfusion imaging agents are reviewed. Potential clinical application of these agents is discussed

  19. Lung perfusion scintigraphy in congenital heart disease

    International Nuclear Information System (INIS)

    Sugimura, Hiroshi; Nagamachi, Shigeki; Hoshi, Hiroaki; Jinnouchi, Seishi; Oonishi, Takashi; Futami, Shigemi; Watanabe, Katsushi

    1990-01-01

    Lung perfusion scintigrams were reviewed retrospectively in 28 patients with congenital heart disease, whose ages ranged from the first year to 16 years with an average age of 5 years and 6 months. Seventy four MBq (2 mCi), 111 MBq (2 mCi), and 185 MBq (5 mCi) of Tc-99m macroaggregated albumin were iv injected in the age groups of 0-3, 4-11, and more than 11 years, respectively. Five minutes later, images were obtained in six projections. Abnormal findings on lung perfusion scintigrams were observed in 13 patients (46%). Of these patients, 8 (29%) had a partially decreased blood flow and 5 (17%) had a decreased blood flow in the unilateral lung. No significant difference in the occurrence of abnormal findings was observed among the age groups, although they tended to occur in younger patients. Sex, underlying conditions, and hemodynamics were also independent of scintigraphically abnormal findings. Even when classifying the patients as having either cyanotic or non-cyanotic heart disease, no significant difference in hemodynamics was observed between the group of abnormal findings and the group of normal findings. Pulmonary arteriography available in all patients failed to reveal abnormal findings, with the exception of pulmonary artery stenosis in 2 patients that corresponded to a decreased blood flow in the unilateral lung. Pulmonary artery stenosis seemed to be responsible for abnormal pulmonary blood flow, although other causes remained uncertain. (N.K.)

  20. Visualization of myocardial perfusion derived from coronary anatomy

    NARCIS (Netherlands)

    Termeer, M.A.; Bescos, J.O.; Breeuwer, M.; Vilanova, A.; Gerritsen, F.A.; Gröller, M.E.; Nagel, Eike

    2008-01-01

    Visually assessing the effect of the coronary artery anatomy on the perfusion of the heart muscle in patients with coronary artery disease remains a challenging task. We explore the feasibility of visualizing this effect on perfusion using a numerical approach. We perform a computational simulation

  1. Perfusion MR imaging for differentiation of benign and malignant meningiomas

    NARCIS (Netherlands)

    Zhang, Hao; Rodiger, Lars A.; Shen, Tianzhen; Miao, Jingtao; Oudkerk, Matthijs

    Introduction Our purpose was to determine whether perfusion MR imaging can be used to differentiate benign and malignant meningiomas on the basis of the differences in perfusion of tumor parenchyma and/or peritumoral edema. Methods A total of 33 patients with preoperative meningiomas (25 benign and

  2. Perfusion Electronic Record Documentation Using Epic Systems Software.

    Science.gov (United States)

    Riley, Jeffrey B; Justison, George A

    2015-12-01

    The authors comment on Steffens and Gunser's article describing the University of Wisconsin adoption of the Epic anesthesia record to include perfusion information from the cardiopulmonary bypass patient experience. We highlight the current-day lessons and the valuable quality and safety principles the Wisconsin-Epic model anesthesia-perfusion record provides.

  3. Hypothermic Machine Perfusion of Kidney Grafts: Which Pressure is Preferred?

    NARCIS (Netherlands)

    Doorschodt, B. M.; Schreinemachers, M. C. J. M.; Behbahani, M.; Florquin, S.; Weis, J.; Staat, M.; Tolba, R. H.

    2011-01-01

    To assess the effect of the perfusion pressure (PP) during machine perfusion (MP) on the preservation quality of kidney grafts, we compared mean PPs of 25 and 30 mmHg using a porcine autotransplantation model. After assessment of the microcirculation, animals underwent left nephrectomy. Thereafter,

  4. Fluid mechanics

    International Nuclear Information System (INIS)

    Paraschivoiu, I.; Prud'homme, M.; Robillard, L.; Vasseur, P.

    2003-01-01

    This book constitutes at the same time theoretical and practical base relating to the phenomena associated with fluid mechanics. The concept of continuum is at the base of the approach developed in this work. The general advance proceeds of simple balances of forces as into hydrostatic to more complex situations or inertias, the internal stresses and the constraints of Reynolds are taken into account. This advance is not only theoretical but contains many applications in the form of solved problems, each chapter ending in a series of suggested problems. The major part of the applications relates to the incompressible flows

  5. Principles of fluid mechanics

    International Nuclear Information System (INIS)

    Kreider, J.F.

    1985-01-01

    This book is an introduction on fluid mechanics incorporating computer applications. Topics covered are as follows: brief history; what is a fluid; two classes of fluids: liquids and gases; the continuum model of a fluid; methods of analyzing fluid flows; important characteristics of fluids; fundamentals and equations of motion; fluid statics; dimensional analysis and the similarity principle; laminar internal flows; ideal flow; external laminar and channel flows; turbulent flow; compressible flow; fluid flow measurements

  6. Perfusion-weighted MR imaging of uterine leiomyoma

    Energy Technology Data Exchange (ETDEWEB)

    Takase, Hiroyasu; Munechika, Hirotsugu [Showa Univ., Tokyo (Japan). School of Medicine

    2001-06-01

    Serial images of uterine leiomyoma in gradient-echo, echo-planar, magnetic resonance imaging were taken to draw a {delta}R2{sup *} curve after intravenous bolus injection of Gd-DTPA. The {delta}R2{sup *} integral was calculated from a {delta}R2{sup *} curve to have relative perfusion of uterine leiomyoma. We then, evaluated the amount of perfusion correlated with MR findings, size and number of leiomyoma or the clinical symptoms and established that perfusion was correlated positively with the findings of T2 weighted images and clinical symptoms but not with other MR findings or size and number of leiomyoma. In conclusion, we presumed that the clinical symptoms could be reduced by decreasing of an amount of perfusion of uterine leiomyoma in some means. However, it remained uncertain why severe clinical symptoms were associated with a high amount of perfusion in uterine leiomyomas. (author)

  7. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke; Sidaros, Karam; Gesmar, Henrik

    2000-01-01

    Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...... of the involved RF pulses are taken into account. A small flow-independent off-set may be present in the data. The off-set is explained by the model. Based on the correspondence between the phantom and the in vivo models, it is shown that the lowest flow values that could be measured in the phantom correspond...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom....

  8. A model system for perfusion quantification using FAIR

    DEFF Research Database (Denmark)

    Andersen, I.K.; Sidaros, Karam; Gesmar, H

    2000-01-01

    Flow-sensitive experiments (FAIR) have been performed on a tube-flow phantom in order to validate quantitative perfusion measurements on humans. A straight-forward correspondence between perfusion and bulk-flow is found. It is shown that the flow phantom model only holds when the slice profiles...... of the involved RF pulses are taken into account. A small flow-independent off-set may be present in the data. The off-set is explained by the model. Based on the correspondence between the phantom and the in vivo models, it is shown that the lowest flow values that could be measured in the phantom correspond...... to perfusion values lower than the cortical perfusion in the brain. Thus, the experimental accuracy and the computational methods for quantitative perfusion measurements in vivo can be validated by a tube-flow phantom...

  9. Pathologic evaluation of normal and perfused term placental tissue

    DEFF Research Database (Denmark)

    Maroun, Lisa Leth; Mathiesen, Line; Hedegaard, Morten

    2014-01-01

    This study reports for the 1st time the incidence and interobserver variation of morphologic findings in a series of 34 term placentas from pregnancies with normal outcome used for perfusion studies. Histologic evaluation of placental tissue is challenging, especially when it comes to defining...... "normal tissue" versus "pathologic lesions." A scoring system for registration of abnormal morphologic findings was developed. Light microscopic examination was performed independently by 2 pathologists, and interobserver variation was analyzed. Findings in normal and perfused tissue were compared...... and selected findings were tested against success parameters from the perfusions. Finally, the criteria for frequent lesions with fair to poor interobserver variation in the nonperfused tissue were revised and reanalyzed. In the perfused tissue, the perfusion artefact "trophoblastic vacuolization," which...

  10. Disappearing fluid?

    International Nuclear Information System (INIS)

    Graney, K.; Chu, J.; Lin, P.C.

    2002-01-01

    Full text: A 78-year old male in end stage renal failure (ESRF) with a background of NIDDM retinopathy, nephropathy, and undergoing continuous ambulatory peritoneal dialysis (CAPD) presented with anorexia, clinically unwell, decreased mobility and right scrotal swelling. There was no difficulty during CAPD exchange except there was a positive fluid balance Peritoneal dialysates remained clear A CAPD peritoneal study was requested. 100Mbq 99mTc Sulphur Colloid was injected into a standard dialysate bag containing dialysate. Anterior dynamic images were acquired over the abdomen pelvis while the dialysate was infused Static images with anatomical markers were performed 20 mins post infusion, before and after patient ambulation and then after drainage. The study demonstrated communication between the peritoneal cavity and the right scrotal sac. Patient underwent right inguinal herniaplasty with a marlex mesh. A repeat CAPD flow study was performed as follow up and no abnormal connection between the peritoneal cavity and the right scrotal sac was demonstrated post operatively. This case study shows that CAPD flow studies can be undertaken as a simple, minimally invasive method to evaluate abnormal peritoneal fluid flow dynamics in patients undergoing CAPD, and have an impact on dialysis management. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  11. Auxillary Fluid Flowmeter

    DEFF Research Database (Denmark)

    RezaNejad Gatabi, Javad; Forouzbakhsh, Farshid; Ebrahimi Darkhaneh, Hadi

    2010-01-01

    The Auxiliary Fluid Flow meter is proposed to measure the fluid flow of any kind in both pipes and open channels. In this kind of flow measurement, the flow of an auxiliary fluid is measured Instead of direct measurement of the main fluid flow. The auxiliary fluid is injected into the main fluid ...

  12. Amnioinfusion in labor induction of term pregnancies with premature rupture of the membranes and low amniotic fluid.

    Science.gov (United States)

    Miño, M; Puertas, A; Herruzo, A J; Miranda, J A

    1998-05-01

    To analyze the utility of prophylactic amnioinfusion in term pregnancies with PROM and a low amniotic fluid index during labor induction. Forty-two women with amnioinfusion and 42 in a control group with amniotic fluid index (AFI) below 10 cm when admitted to labor induction were studied. All patients had electronic fetal heart rate and intrauterine pressure continuous monitoring. Amnioinfusion of normal saline (37 degrees C) was realized in the study group, using a continuous perfusion pump at 600 ml/h for 1 h, after which the AFI was again recorded; if this was amnioinfusion. Both groups were similar in age, primiparity, gestational age, initial AFI, interval from rupture of membranes until delivery and length of labor. The amnioinfusion of 600 ml in 1 h significantly increased the AFI (an increase of 7.2 +/- 3.9 vs. a decrease of 1.1 +/- 1.6, P amnioinfusion group, there was a significantly lower rate of cesarean deliveries (0 vs. 6, P amnioinfusion improves neonatal metabolic state when used in labor induction of term pregnancies with PROM and a low amniotic fluid index.

  13. Nifedipine and thallium-201 myocardial perfusion in progressive systemic sclerosis

    International Nuclear Information System (INIS)

    Kahan, A.; Devaux, J.Y.; Amor, B.

    1986-01-01

    Heart disease in patients with progressive systemic sclerosis may be due in part to myocardial ischemia caused by a disturbance of the coronary microcirculation. To determine whether abnormalities of myocardial perfusion in this disorder are potentially reversible, we evaluated the effect of the coronary vasodilator nifedipine on myocardial perfusion assessed by thallium-201 scanning in 20 patients. Thallium-201 single-photon-emission computerized tomography was performed under control conditions and 90 minutes after 20 mg of oral nifedipine. The mean (+/- SD) number of left ventricular segments with perfusion defects decreased from 5.3 +/- 2.0 to 3.3 +/- 2.2 after nifedipine (P = 0.0003). Perfusion abnormalities were quantified by a perfusion score (0 to 2.0) assigned to each left ventricular segment and by a global perfusion score (0 to 18) for the entire left ventricle. The mean perfusion score in segments with resting defects increased from 0.97 +/- 0.24 to 1.26 +/- 0.44 after nifedipine (P less than 0.00001). The mean global perfusion score increased from 11.2 +/- 1.7 to 12.8 +/- 2.4 after nifedipine (P = 0.003). The global perfusion score increased by at least 2.0 in 10 patients and decreased by at least 2.0 in only 1. These observations reveal short-term improvement in thallium-201 myocardial perfusion with nifedipine in patients with progressive systemic sclerosis. The results are consistent with a potentially reversible abnormality of coronary vasomotion in this disorder, but the long-term therapeutic effects of nifedipine remain to be determined

  14. TNFa-based isolated limb perfusion in the rat : development of a model and analysis of efficacy determining factors

    NARCIS (Netherlands)

    E.R. Manusama (Eric)

    1998-01-01

    textabstractIsolated limb perfusion (lLP) with high dose TNFa in combination with IFNr and melphalan in patients with melanoma in transit metastases confined to the limb has recently been reported to result in much higher complete tumor response rates than after the standard therapy of ILP with

  15. Value of chest X-ray combined with perfusion scan versus ventilation/perfusion scan in acute pulmonary embolism

    NARCIS (Netherlands)

    de Groot, M. R.; Turkstra, F.; van Marwijk Kooy, M.; Oostdijk, A. H.; van Beek, E. J.; Büller, H. R.

    2000-01-01

    The main purpose of ventilation scanning, as adjunct to perfusion lung scintigraphy, in acute pulmonary embolism is to allow for the classification of segmental perfusion defects as mismatched, which is generally accepted as proof for the presence of pulmonary embolism. We examined whether this

  16. Removal of unwanted fluid

    Science.gov (United States)

    Subudhi, Sudhakar; Sreenivas, K. R.; Arakeri, Jaywant H.

    2013-01-01

    This work is concerned with the removal of unwanted fluid through the source-sink pair. The source consists of fluid issuing out of a nozzle in the form of a jet and the sink is a pipe that is kept some distance from the source pipe. Of concern is the percentage of source fluid sucked through the sink. The experiments have been carried in a large glass water tank. The source nozzle diameter is 6 mm and the sink pipe diameter is either 10 or 20 mm. The horizontal and vertical separations and angles between these source and sink pipes are adjustable. The flow was visualized using KMnO4 dye, planer laser induced fluorescence and particle streak photographs. To obtain the effectiveness (that is percentage of source fluid entering the sink pipe), titration method is used. The velocity profiles with and without the sink were obtained using particle image velocimetry. The sink flow rate to obtain a certain effectiveness increase dramatically with lateral separation. The sink diameter and the angle between source and the sink axes don't influence effectiveness as much as the lateral separation.

  17. Technical and theoretical considerations about gradient perfusion culture for epithelia used in tissue engineering, biomaterial testing and pharmaceutical research

    Energy Technology Data Exchange (ETDEWEB)

    Minuth, Will W [Department of Molecular and Cellular Anatomy, University of Regensburg, D-93053 Regensburg, University Street 31 (Germany); Strehl, Raimund [Cellartis AB, S-41346 Goeteborg, Arvid Wallgrens Backe 20 (Sweden)

    2007-06-01

    Epithelia act as biological barriers, which are exposed to different environments at the luminal and basal sides. To simulate this situation and to improve functional features an in vitro gradient perfusion culture technique was developed in our laboratory. This innovative technique appears to be simple at first sight, but the performance needs practical and theoretical knowledge. To harvest intact epithelia after a long-term gradient culture period of many days, leakage, edge damage and pressure differences in the system have to be avoided so that the epithelial barrier function is maintained continuously. Unexpectedly, one of the major obstacles are micro-injuries in the epithelia caused by gas bubbles, which arise during transportation of the medium or due to respiration of the cultured tissue. Gas bubbles randomly accumulate either at the luminal or basal fluid flow of the gradient perfusion culture container. This phenomenon results in fluid pressure differences between the luminal and basal perfusion compartments of the gradient container, which in turn leads to damage of the barrier function. Consequently, the content of gas bubbles in the transported culture medium has to be minimized. Thus, our technical concept is the reduction of gas bubbles while keeping the content of oxygen constant. To follow this strategy we developed a new type of screw cap for media bottles specifically designed to allow fluid contact only with tube and not with cap material. Furthermore, a gas expander module separates gas bubbles from the liquid phase during transportation of the medium. Finally, a new type of gradient culture container allows a permanent elimination of transported gas bubbles. Application of this innovative equipment optimizes the parallel transportation of fluid in the luminal and basal compartments of a gradient culture container. (topical review)

  18. Technical and theoretical considerations about gradient perfusion culture for epithelia used in tissue engineering, biomaterial testing and pharmaceutical research

    International Nuclear Information System (INIS)

    Minuth, Will W; Strehl, Raimund

    2007-01-01

    Epithelia act as biological barriers, which are exposed to different environments at the luminal and basal sides. To simulate this situation and to improve functional features an in vitro gradient perfusion culture technique was developed in our laboratory. This innovative technique appears to be simple at first sight, but the performance needs practical and theoretical knowledge. To harvest intact epithelia after a long-term gradient culture period of many days, leakage, edge damage and pressure differences in the system have to be avoided so that the epithelial barrier function is maintained continuously. Unexpectedly, one of the major obstacles are micro-injuries in the epithelia caused by gas bubbles, which arise during transportation of the medium or due to respiration of the cultured tissue. Gas bubbles randomly accumulate either at the luminal or basal fluid flow of the gradient perfusion culture container. This phenomenon results in fluid pressure differences between the luminal and basal perfusion compartments of the gradient container, which in turn leads to damage of the barrier function. Consequently, the content of gas bubbles in the transported culture medium has to be minimized. Thus, our technical concept is the reduction of gas bubbles while keeping the content of oxygen constant. To follow this strategy we developed a new type of screw cap for media bottles specifically designed to allow fluid contact only with tube and not with cap material. Furthermore, a gas expander module separates gas bubbles