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Sample records for blood flow measurement

  1. Endovascular blood flow measurement system

    Science.gov (United States)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper an endovascular measurement system used for intraoperative cerebral blood flow monitoring is described. The system is based on a Volcano ComboMap Pressure and Flow System extended with analogue-to-digital converter and PC laptop. A series of measurements performed in patients with cerebrovascular pathologies allows us to introduce “velocity-pressure” and “flow rate-energy flow rate” diagrams as important characteristics of the blood flow. The measurement system presented here can be used as an additional instrument in neurosurgery for assessment and monitoring of the operation procedure. Clinical data obtained with the system are used for construction of mathematical models and patient-specific simulations. The monitoring of the blood flow parameters during endovascular interventions was approved by the Ethics Committee at the Meshalkin Novosibirsk Research Institute of Circulation Pathology and included in certain surgical protocols for pre-, intra- and postoperative examinations.

  2. Preclinical Arterial Spin Labeling Measurement of Cerebral Blood Flow.

    Science.gov (United States)

    Muir, Eric R

    2018-01-01

    Magnetic resonance imaging has been utilized as a quantitative and noninvasive method to image blood flow. Arterial spin labeling (ASL) is an MRI technique that images blood flow using arterial blood water as an endogenous tracer. Herein we describe the use of ASL to measure cerebral blood flow completely noninvasively in rodents, including methods, analysis, and important considerations when utilizing this technique.

  3. Accurate Blood Flow Measurements : Are Artificial Tracers Necessary?

    NARCIS (Netherlands)

    Poelma, C.; Kloosterman, A.; Hierck, B.P.; Westerweel, J.

    2012-01-01

    Imaging-based blood flow measurement techniques, such as particle image velocimetry, have become an important tool in cardiovascular research. They provide quantitative information about blood flow, which benefits applications ranging from developmental biology to tumor perfusion studies. Studies

  4. Aortic blood flow subtraction: an alternative method for measuring total renal blood flow in conscious dogs

    DEFF Research Database (Denmark)

    Sandgaard, N C F; Andersen, J L; Holstein-Rathlou, N-H

    2002-01-01

    We have measured total renal blood flow (TRBF) as the difference between signals from ultrasound flow probes implanted around the aorta above and below the renal arteries. The repeatability of the method was investigated by repeated, continuous infusions of angiotensin II and endothelin-1 seven...... arterial blood pressure by 49% and decreased TRBF by 12%, providing an increase in renal vascular resistance of 69%. Dynamic analysis showed autoregulation of renal blood flow in the frequency range ... of TRBF by aortic blood flow subtraction is a practical and reliable method that allows direct comparison of excretory function and renal blood flow from two kidneys. The method also allows direct comparison between TRBF and flow in the caudal aorta....

  5. Measurement of organ blood flow using tritiated water. II. Uterine blood flow in conscious pregnant ewes

    International Nuclear Information System (INIS)

    Brown, B.W.; Oddy, V.H.; Jones, A.W.

    1982-01-01

    Total uterine blood flow was measured with a tritiated water (TOH) diffusion method and with radioactive microspheres in six, conscious, pregnant ewes. With continuous infusion of TOH, equilibrium between the TOH concentration in utero-ovarian venous blood and arterial blood was attained within 50 min of the start of the infusion. The concentration of TOH in uterine and foetal tissue and in foetal blood water was the same as that in uterine venous water by 40 min; at this time, the concentration of TOH in the water of amniotic and allantoic fluids was 96% of that in uterine venous blood water. Estimates of total uterine blood flow obtained using TOH were highly correlated with those obtained with microspheres and the corresponding mean flow values obtained with the two techniques did not significantly differ. The percentage of the total uterine blood flow passing through arteriovenous anastomoses ranged from 1.4 to 3.3%

  6. Our experience of blood flow measurements using radioactive tracers

    International Nuclear Information System (INIS)

    Danet, Bernard.

    1974-01-01

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

  7. Simple Radiowave-Based Method for Measuring Peripheral Blood Flow

    Data.gov (United States)

    National Aeronautics and Space Administration — Project objective is to design small radio frequency based flow probes for the measurement of blood flow velocity in peripheral arteries such as the femoral artery...

  8. Measurement of absolute bone blood flow by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nahmias, C.; Cockshott, W.P.; Garnett, E.S.; Belbeck, L.W.

    1986-03-01

    A method of measuring bone blood flow has been developed using /sup 18/F sodium fluoride and positron emission tomography. The blood flow levels are in line with those obtained experimentally from microsphere embolisation. This investigative method could be applied to elucidate a number of clinical questions involving bone perfusion.

  9. Noninvasive measurement of blood flow and extraction fraction

    International Nuclear Information System (INIS)

    Peters, A.M.; Gunasekera, R.D.; Henderson, B.L.; Brown, J.; Lavender, J.P.; De Souza, M.; Ash, J.M.; Gilday, D.L.

    1987-01-01

    We describe the theory of a technique for the noninvasive measurement of organ blood flow which is based on the principle of fractionation of cardiac output and is applicable with any recirculating gamma emitting tracer. The technique effectively determines the count rate that would be recorded over the organ if the tracer behaved like radiolabelled microspheres and was completely trapped in the organ's vascular bed on first pass. After correction for organ depth, the estimated first pass activity plateau, expressed as a fraction of the injected dose is equal to the organ's fraction of the cardiac output (CO). By extending the theory, organ extraction fraction of extractable tracers or mean transit time of nonextractable tracers can be measured. The technique was applied to the measurement of renal blood flow in the native and transplanted kidney, splenic blood flow, the extraction fraction of DTPA by the kidney and of sulphur colloid by the spleen. (author)

  10. Computational fluid dynamics using in vivo ultrasound blood flow measurements

    DEFF Research Database (Denmark)

    Traberg, Marie Sand; Pedersen, Mads Møller; Hemmsen, Martin Christian

    2012-01-01

    This paper presents a model environment for construction of patient-specific computational fluid dynamic (CFD) models for the abdominal aorta (AA). Realistic pulsatile velocity waveforms are employed by using in vivo ultrasound blood flow measurements. Ultrasound is suitable for acquisition...

  11. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular...... simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50-100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic...... techniques for extracting the desired data and for examining them for evidence of nephron synchronization. Synchronized TGF oscillations were detected in pairs or triplets of nephrons. The amplitude and the frequency of the oscillations changed with time, as did the patterns of synchronization...

  12. Accurate Blood Flow Measurements: Are Artificial Tracers Necessary?

    Science.gov (United States)

    Poelma, Christian; Kloosterman, Astrid; Hierck, Beerend P.; Westerweel, Jerry

    2012-01-01

    Imaging-based blood flow measurement techniques, such as particle image velocimetry, have become an important tool in cardiovascular research. They provide quantitative information about blood flow, which benefits applications ranging from developmental biology to tumor perfusion studies. Studies using these methods can be classified based on whether they use artificial tracers or red blood cells to visualize the fluid motion. We here present the first direct comparison in vivo of both methods. For high magnification cases, the experiments using red blood cells strongly underestimate the flow (up to 50% in the present case), as compared to the tracer results. For medium magnification cases, the results from both methods are indistinguishable as they give the same underestimation of the real velocities (approximately 33%, based on in vitro reference measurements). These results suggest that flow characteristics reported in literature cannot be compared without a careful evaluation of the imaging characteristics. A method to predict the expected flow averaging behavior for a particular facility is presented. PMID:23028878

  13. Rotating permanent magnet excitation for blood flow measurement.

    Science.gov (United States)

    Nair, Sarath S; Vinodkumar, V; Sreedevi, V; Nagesh, D S

    2015-11-01

    A compact, portable and improved blood flow measurement system for an extracorporeal circuit having a rotating permanent magnetic excitation scheme is described in this paper. The system consists of a set of permanent magnets rotating near blood or any conductive fluid to create high-intensity alternating magnetic field in it and inducing a sinusoidal varying voltage across the column of fluid. The induced voltage signal is acquired, conditioned and processed to determine its flow rate. Performance analysis shows that a sensitivity of more than 250 mV/lpm can be obtained, which is more than five times higher than conventional flow measurement systems. Choice of rotating permanent magnet instead of an electromagnetic core generates alternate magnetic field of smooth sinusoidal nature which in turn reduces switching and interference noises. These results in reduction in complex electronic circuitry required for processing the signal to a great extent and enable the flow measuring device to be much less costlier, portable and light weight. The signal remains steady even with changes in environmental conditions and has an accuracy of greater than 95%. This paper also describes the construction details of the prototype, the factors affecting sensitivity and detailed performance analysis at various operating conditions.

  14. Tomographic cerebral blood flow measurement during carotid surgery

    DEFF Research Database (Denmark)

    Rathenborg, Lisbet Knudsen; Vorstrup, Sidsel; Olsen, K S

    1994-01-01

    surgery and performing single photon emission computer tomography (SPECT) scanning shortly after the operation thereby pictures rCBF at the time of injection. DESIGN: Ongoing prospective study. SETTINGS: Departments of Vascular Surgery, Neurology and Anaesthesiology, University Hospital, Rigshospitalet......OBJECTIVES: The aim of the study was to depict regional cerebral blood flow (rCBF) during carotid cross clamping using 99mTechnetium-hexamethylpropylene amine oxime (TcHMPAO). This tracer rapidly passes the blood-brain barrier and is retained for hours in the brain tissue. Injecting TcHMPAO during......, Copenhagen, Denmark. MATERIAL: 15 patients who during a period of 4 months underwent carotid endarterectomy. CHIEF OUTCOME MEASURES: Prior to surgery rCBF was determined using 133Xe and SPECT. Intraoperatively stump pressure was measured and a bolus of TcHMPAO was injected for later SPECT measurement. MAIN...

  15. Measurement of regional cerebral blood flow by positron emission tomography

    International Nuclear Information System (INIS)

    Herscovitch, P.; Powers, W.J.

    1987-01-01

    The principal advantage of positron emission tomography over other methods for measuring cerebral blood flow stems from the accurate, quantitative three-dimensional measurements of regional brain radioactivity that are possible with this technique. As a result, accurate quantitative measurements of regional cerebral blood flow can be obtained for both superficial and deep cerebral structures. The value of PET for investigating central nervous system physiology and pathology extends far beyond this, however. Through the use of different radiotracers and appropriate mathematical models, PET can be applied to the measurement of a wide variety of physiologic variables. Measurements of rCBF tell only part of the story. Experience with PET and with a variety of other techniques has taught us that rCBF is at times a poor indicator of the metabolic, functional, and biochemical status of cerebral tissue. It is only by understanding the interaction of all of these factors that our understanding of neurologic disease can advance. It is in the investigation of these complex relationships that the real value of PET resides

  16. Simultaneous measurement of erythrocyte deformability and blood viscoelasticity using micropillars and co-flowing streams under pulsatile blood flows.

    Science.gov (United States)

    Kang, Yang Jun

    2017-01-01

    The biophysical properties of blood provide useful information on the variation in hematological disorders or diseases. In this study, a simultaneous measurement method of RBC (Red Blood Cell) deformability and blood viscoelasticity is proposed by evaluating hemodynamic variations through micropillars and co-flowing streams under sinusoidal blood flow. A disposable microfluidic device is composed of two inlets and two outlets, two upper side channels, and two lower side channels connected to one bridge channel. First, to measure the RBC deformability, the left-lower side channel has a deformability assessment chamber (DAC) with narrow-sized micropillars. Second, to evaluate the blood viscoelasticity in co-flowing streams, a phosphate buffered saline solution is supplied at a constant flow rate. By closing or opening a pinch valve connected to the outlet of DAC, blood flows in forward or back-and-forth mode. A time-resolved micro-particle image velocimetry technique and a digital image processing technique are used to quantify the blood velocity and image intensity. Then, RBC deformability is evaluated by quantifying the blood volume passing through the DAC under forward flow, and quantifying the variations of blood velocity and image intensity in the DAC under back-and-forth flow. Using a discrete circuit model, blood viscoelasticity is obtained by evaluating variations of blood velocity and co-flowing streams. The effect of several factors (period, hematocrit, and base solution) on the performance is quantitatively evaluated. Based on the experimental results, the period of sinusoidal flow and hematocrit are fixed at 30 s and 50%, respectively. As a performance demonstration, the proposed method is employed to detect the homogeneous and heterogeneous blood composed of normal RBCs and hardened RBCs. These experimental results show that the RBC deformability is more effective to detect minor subpopulations of heterogeneous bloods, compared with blood viscoelasticity

  17. Cutaneous and subcutaneous blood flow measurements in psoriasis

    International Nuclear Information System (INIS)

    Klemp, P.

    1987-01-01

    The experiments - published in 7 papers in The Journal of Investigative Dermatology 1983-86 - have demonstrated: 1. The accuracy of the local 133 Xe washout method is about 15% for estimation of the cutaneous blood flow (CBF), and about 10% for subcutaneous blood flow measurements (SBF). In measurements of absolute CBF values a graphic curve resolution of the washout curve should alwaus be performed. Otherwise the CBF might be considerably underestimated. 2. CdTe(Cl) mini-detectors can be attached directly to the skin, and might yield measurements of both CBF and SBF that can substitute for those made with conventional detectors. 3. The laser Doppler measurements could not be correlated to quantitative measurements of the CBF. 4. The tissue-to-blood partition coefficient for 133 Xe of lesional psoriatic skin (LS) is increased. 5. In untreated, LS of patients with active psoriasis the CBF is about a factor of 10 times higher than the CBF of normal individuals. In non-lesional skin (NLS) of patients with active psoriasis the CBF is about a factor of 2 higher than the CBF of normal individuals. However, the CBF did not differ in NLS of patients with minimal skin manifestations. The high CBF decreases gradualy during antipsoriatic treatment. 6. A paradoxical autoregulation of the CBF was observed in LS. 7. The high CBF is not due to a maximally dilated vascular bed. 8. The SBF in LS areas was a factor of higher than the SBF in normal individuals. 9. A normal, local regulation of the SBF was found. (author)

  18. Usefulness of measurement of blood flow by RI plethysmography

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Kenji; Ling, Qing Cheng; Mori, Yutaka; Tanaka, Uzuru; Shimada, Takao [Jikei Univ., Tokyo (Japan). School of Medicine

    1997-03-01

    We have developed the RI plethysmography, and have applied it to ordinary clinic diagnosis and the evaluation of treatment. The subjects were 58 cases (39 cases of the obstruction of the peripheral blood circulation: ASO 24 cases, TAO 4 cases and arterial sclerotic change 11 cases; the non-abnormal control was 19 cases). The clinical benefit of this method was evaluated. In the cases with 1 and 2 degrees of Fontaine`s classification and ASO and TAO, the blood flow of legs measured by our method significantly decreased in association with symptoms and angiographic findings. This method is suitable to the determination of angiography and evaluation of the effect of treatment. (author)

  19. Novel laser Doppler flowmeter for pulpal blood flow measurements

    Science.gov (United States)

    Zang, De Yu; Millerd, James E.; Wilder-Smith, Petra B. B.; Arrastia-Jitosho, Anna-Marie A.

    1996-04-01

    We have proposed and experimentally demonstrated a new configuration of laser Doppler flowmetry for dental pulpal blood flow measurements. To date, the vitality of a tooth can be determined only by subjective thermal or electric tests, which are of questionable reliability and may induced pain in patient. Non-invasive techniques for determining pulpal vascular reactions to injury, treatment, and medication are in great demand. The laser Doppler flowmetry technique is non-invasive; however, clinical studies have shown that when used to measure pulpal blood flow the conventional back-scattering Doppler method suffers from low signal-to-noise ratio (SNR) and unreliable flux readings rendering it impossible to calibrate. A simplified theoretical model indicates that by using a forward scattered geometry the detected signal has a much higher SNR and can be calibrated. The forward scattered signal is readily detectable due to the fact that teeth are relatively thin organs with moderate optical loss. A preliminary experiment comparing forward scattered detection with conventional back- scattered detection was carried out using an extracted human molar. The results validated the findings of the simple theoretical model and clearly showed the utility of the forward scattering geometry. The back-scattering method had readings that fluctuated by as much as 187% in response to small changes in sensor position relative to the tooth. The forward scattered method had consistent readings (within 10%) that were independent of the sensor position, a signal-to-noise ratio that was at least 5.6 times higher than the back-scattering method, and a linear response to flow rate.

  20. Chronic intestinal ischaemia: measurement of the total splanchnic blood flow.

    Science.gov (United States)

    Zacho, Helle D

    2013-04-01

    A redundant collateral network between the intestinal arteries is present at all times. In case of ischaemia in the gastrointestinal tract, the collateral blood supply can develop further, thus accommodating the demand for oxygen even in the presence of significant stenosis or occlusion of the intestinal arteries without clinical symptoms of intestinal ischaemia. Symptoms of ischemia develop when the genuine and collateral blood supply no longer can accommodate the need for oxygen. Atherosclerosis is the most common cause of obliteration in the intestinal arteries. In chronic intestinal ischaemia (CII), the fasting splanchnic blood flow (SBF) is sufficient, but the postprandial increase in SBF is inadequate and abdominal pain will therefore develop in relation to food intake causing the patient to eat smaller meals at larger intervals with a resulting weight loss. Traditionally, the CII-diagnosis has exclusively been based upon morphology (angiography) of the intestinal arteries; however, substantial discrepancies between CII-symptoms and the presence of atherosclerosis/stenosis in the intestinal arteries have been described repeatedly in the literature impeding the diagnosis of CII. This PhD thesis explores a method to determine the total SBF and its potential use as a diagnostic tool in patients suspected to suffer from CII. The SBF can be measured using a continuous infusion of a tracer and catheterisation of a hepatic vein and an artery. By measuring the SBF before and after a standard meal it is possible to assess the ability or inability to enhance the SBF and thereby diagnosing CII. In Study I, measurement of SBF was tested against angiography in a group of patients suspected to suffer from CII due to pain and weight loss. A very good agreement between the postprandial increase in SBF and angiography was found. The method was validated against a well-established method independent of the hepatic extraction of tracer using pAH in a porcine model (study II

  1. The measurement of limb blood flow using technetium-labelled red blood cells

    International Nuclear Information System (INIS)

    Parkin, A; Robinson, P.J.; Wiggins, P.A.; Leveson, S.H.; Salter, M.C.P.; Matthews, I.F.; Ware, F.M.

    1986-01-01

    A method for measuring blood flow below the knee during reactive hyperaemia induced by 3 min of arterial occlusion has been developed. Subjects are positioned with lower limbs within the field of view of a gamma camera and pneumatic cuffs are placed below the knees to isolate the blood and induce a hyperaemic response. The remaining blood pool is labelled with 99 Tcsup(m)-labelled red cells. Blood flows have been derived from the initial gradients of time-activity curves and from equilibrium blood sampling. The technique has been validated using a tissue-equivalent leg phantom and peristaltic pump. The method has been applied to a small group of patients with peripheral vascular disease and to normal controls. The mean value (+-SD) of limb perfusion for normal controls was found to be 16.4+-3.0 ml/100 ml/min and for patients with intermittent claudication was 5.1+-2.6 ml/100 ml/min. Flow measurements are found to correlate with clinical findings and with symptoms. Reproducibility (established by repeated measurements) is high. The method is well tolerated even by patients suffering from rest pain. (author)

  2. Novel approach to laser Doppler measurement of pulpal blood flow

    Science.gov (United States)

    Zang, De Yu; Wilder-Smith, Petra B.; Millerd, James E.; Arrastia-Jitosho, Anna-Marie A.

    1997-07-01

    A modified laser Doppler flowmetry technique that significantly improves the performance of the current technique in measuring pulpal blood flow is described. A preliminary model demonstrates that, by using a forward- scattering geometry, the detected signal will have a much higher signal-to-noise ratio and calibration capacity. The forward-scattered signal is readily detectable because teeth are relatively thin organs with moderate optical loss. Preliminary experiments comparing forward-scattered detection with conventional back-scattered detection were carried out using an extracted, perfused human molar. The results showed that: (1) the existing back-scattering method produced readings that fluctuated by as much as 187% in response to small changes in sensor position relative to the tooth and (2) the forward-scattered method produced consistent readings (within 10%) that were independent of the sensor position, a signal-to-noise ratio that was at least 5.6 times higher than that obtained by the back- scattering method, and a linear response to flow rate. The results validated the findings of the preliminary model and clearly showed the superiority of the forward-scattering geometry.

  3. Distribution of the pulmonary blood flow measured by ECT

    International Nuclear Information System (INIS)

    Maeda, Hisatoshi; Itoh, Harumi; Todo, Yoshiro; Ishii, Yasushi; Mukai, Takao

    1981-01-01

    Distributions of pulmonary blood flow per unit lung volume were observed by using the combination of Tc-99m-MAA and radionuclide CT. Administration of Tc-99m-MAA to the patients were performed in sitting position. Ten patients were studied with this method. In nine patients, the blood flow distribution was greater in the direction of the gravity, namely, more blood flow in the lower than the upper lung region. In six patients were demonstrated the relation between blood flow and the vertical distance described by West et al. Thus, it was possible to evaluate the arterial and venous pressures of the lung with the estimated pressure of 4.15 +- 1.93 cmH 2 O and -5.55 +- 2.48 cmH 2 O in relation to the angle of Louis. The agreement was reasonably well with that reported by Butler and Paley. Three patients had pulmonary hypertension with the distribution of monotonous increase, of which slope was similar to that of zone III in other six patients. The last patient with COPD had quite different distribution from other nine patients. (author)

  4. Occlusion cuff for routine measurement of digital blood pressure and blood flow

    DEFF Research Database (Denmark)

    Lassen, N A; Krähenbühl, B; Hirai, M

    1977-01-01

    A miniaturized blood pressure cuff made of plastic material and applicable to fingers and toes is described. The cuff was compared to rubber cuffs and to bladder-free cuffs. It was found to be more reliable than the former type and much easier to use than the latter type. It is recommended for us...... in conjunction with a mercury-in-Silastic strain gauge for routine measurement of digital blood pressure and blood flow in patients with arterial disease.......A miniaturized blood pressure cuff made of plastic material and applicable to fingers and toes is described. The cuff was compared to rubber cuffs and to bladder-free cuffs. It was found to be more reliable than the former type and much easier to use than the latter type. It is recommended for use...

  5. Noninvasive 133Xe inhalation method for cerebral blood flow measurement

    International Nuclear Information System (INIS)

    Takagi, Shigeharu; Kobatake, Keitaro; Shinohara, Yukito

    1991-01-01

    Recent development of the 133 Xe inhalation technique has made it possible to measure cerebral blood flow (CBF) noninvasively. Recording of the head curves from the frontal and temporal areas during inhalation of 133 Xe, however, is contaminated by the artifact from the air passages. A method based on Fourier transforms was reported to be able to eliminate air passage artifact (APA) effectively. However, it was pointed out that such an algorithm does not give a complete correction if the artifact seen by the head detectors differs in shape from that recorded from the airways at the mouth, which may happen when there is a slow isotope convection in the nasal and sinus cavities. The purpose of this study was to compare the CBF values calculated by the Fourier method with those by the conventional method of Obrist (VM method). Mean hemispheric gray matter flow (F 1 ) calculated by the VM method in 11 subjects, including normal volunteers and patients with various neurological diseases, was 69.2±13.2 mg/100 g brain/ min, whereas F 1 calculated by the Fourier method in the same subjects was 64.4±13.5, indicating that APA can be effectively eliminated by the Fourier method. The F 1 values calculated by the Fourier method from the frontal and temporal regions were relatively high, and closer to the F 1 values calculated by the VM method. The size of the APA was large in these regions. It was concluded that the deformed APA contaminated the results in these regions, and could not be eliminated effectively by the Fourier method. It is suggested that the shape of the head curve and the size of APA should be carefully examined to ensure that CBF data are reliable. (author)

  6. In vivo evaluation of femoral blood flow measured with magnetic resonance

    International Nuclear Information System (INIS)

    Henriksen, O.; Staahlberg, F.; Thomsen, C.; Moegelvang, J.; Persson, B.; Lund Univ.

    1989-01-01

    Quantitative measurements of blood flow based on magnetic resonance imaging (MRI) using conventional multiple spin echo sequences were evaluated in vivo in healthy young volunteers. Blood flow was measured using MRI in the femoral vein. The initial slope of the multiple spin echo decay curve, corrected for the T2 decay of non-flowing blood was used to calculate the blood flow. As a reference, the blood flow in the femoral artery was measured simultaneously with an invasive indicator dilution technique. T2 of non-flowing blood was measured in vivo in popliteal veins during regional circulatory arrest. The mean T2 of non-flowing blood was found to be 105±31 ms. The femoral blood flow ranged between 0 and 643 ml/min measured with MRI and between 280 and 531 ml/min measured by the indicator dilution technique. There was thus poor agreement between the two methods. The results indicate that in vivo blood flow measurements made with MRI based on wash-out effects, commonly used in multiple spin echo imaging, do not give reliable absolute values for blood flow in the femoral artery or vein. (orig.)

  7. X-ray PIV measurements of blood flows without tracer particles

    International Nuclear Information System (INIS)

    Kim, Guk Bae; Lee, Sang Joon

    2006-01-01

    We analyzed the non-Newtonian flow characteristics of blood moving in a circular tube flow using an X-ray PIV method and compared the experimental results with hemodynamic models. The X-ray PIV method was improved for measuring quantitative velocity fields of blood flows using a coherent synchrotron X-ray. Without using any contrast media, this method can visualize flow pattern of blood by enhancing the phase-contrast and interference characteristics of blood cells. The enhanced X-ray images were achieved by optimizing the sample-to-scintillator distance, the sample thickness, and hematocrit in detail. The quantitative velocity fields of blood flows inside opaque conduits were obtained by applying a two-frame PIV algorithm to the X-ray images of the blood flows. The measured velocity data show typical features of blood flow such as the yield stress and shear-thinning effects. (orig.)

  8. X-ray PIV measurements of blood flows without tracer particles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Guk Bae; Lee, Sang Joon [Pohang University of Science and Technology, Department of Mechanical Engineering, Pohang (Korea)

    2006-08-15

    We analyzed the non-Newtonian flow characteristics of blood moving in a circular tube flow using an X-ray PIV method and compared the experimental results with hemodynamic models. The X-ray PIV method was improved for measuring quantitative velocity fields of blood flows using a coherent synchrotron X-ray. Without using any contrast media, this method can visualize flow pattern of blood by enhancing the phase-contrast and interference characteristics of blood cells. The enhanced X-ray images were achieved by optimizing the sample-to-scintillator distance, the sample thickness, and hematocrit in detail. The quantitative velocity fields of blood flows inside opaque conduits were obtained by applying a two-frame PIV algorithm to the X-ray images of the blood flows. The measured velocity data show typical features of blood flow such as the yield stress and shear-thinning effects. (orig.)

  9. Measurement of Finger Blood Flow in Raynauds Phenomenon by Radionuclide Angiography

    International Nuclear Information System (INIS)

    Lim, Sang Moo; Chung, June Key; Lee, Myung Chul; Kim, Sang Joon; Choi, Sung Jae; Koh, Chang Soon

    1987-01-01

    In Raynauds phenomenon, the authors measured finger blood flow after ice water exposure by analyzing the time activity curve of radionuclide angiography on both hands. The results were as follows: 1) The digital blood flow did not decrease after ice water exposure in normal subjects. 2) In the patients with Raynauds phenomenon, there were two groups: the one had decreased digital blood flow after cold exposure, and the other had paradoxically increased digital blood flow after cold exposure. 3) There was no difference in the digital blood flow of hand in room temperature between the normal and the patients with reduced digital blood flow after cold exposure, but the digital blood flow of the hand in room temperature was markedly reduced in the patients with paradoxically increased flow after cold exposure. 4) In the static image the difference was not significant in comparison with the dynamic study, because it represents pooling of the blood in the vein rather than flow. 5) After the treatment with nifedipine, the digital blood flow increased. In conclusion, the radionuclide angiography was useful in measuring the digital blood flow in Raynauds phenomenon, and further studies with various drugs is expected.

  10. Trial on MR portal blood flow measurement with phase contrast technique

    International Nuclear Information System (INIS)

    Tsunoda, Masatoshi; Kimoto, Shin; Togami, Izumi

    1991-01-01

    Portal blood flow measurement is considered to be important for the analysis of hemodynamics in various liver diseases. The Doppler ultrasound method has been used extensively during the past several years for measuring portal blood flow, as a non-invasive method. However, the Doppler ultrasound technique do not allow the portal blood flow to be measured in cases of obesity, with much intestinal gas, and so on. In this study, we attempted to measure the blood flow in the main trunk of portal vein as an application of MR phase contrast technique to the abdominal region. In the flow phantom study, the flow volumes and the velocities measured by phase contrast technique showed a close correlation with those measured by electromagnetic flowmeter. In the clinical study with 10 healthy volunteers, various values of portal blood flow were obtained. Mean portal blood flow could be measured within the measuring time (about 8 minutes) under natural breathing conditions. Phase contrast technique is considered to be useful for the non-invasive measurement of portal blood flow. (author)

  11. Optical measurement of blood flow in exercising skeletal muscle: a pilot study

    Science.gov (United States)

    Wang, Detian; Baker, Wesley B.; Parthasarathy, Ashwin B.; Zhu, Liguo; Li, Zeren; Yodh, Arjun G.

    2017-07-01

    Blood flow monitoring during rhythm exercising is very important for sports medicine and muscle dieases. Diffuse correlation spectroscopy(DCS) is a relative new invasive way to monitor blood flow but suffering from muscle fiber motion. In this study we focus on how to remove exercise driven artifacts and obtain accurate estimates of the increase in blood flow from exercise. Using a novel fast software correlator, we measured blood flow in forearm flexor muscles of N=2 healthy adults during handgrip exercise, at a sampling rate of 20 Hz. Combining the blood flow and acceleration data, we resolved the motion artifact in the DCS signal induced by muscle fiber motion, and isolated the blood flow component of the signal from the motion artifact. The results show that muscle fiber motion strongly affects the DCS signal, and if not accounted for, will result in an overestimate of blood flow more than 1000%. Our measurements indicate rapid dilation of arterioles following exercise onset, which enabled blood flow to increase to a plateau of 200% in 10s. The blood flow also rapidly recovered to baseline following exercise in 10s. Finally, preliminary results on the dependence of blood flow from exercise intensity changes will be discussed.

  12. Measurement of hemodynamic changes with the axial flow blood pump installed in descending aorta.

    Science.gov (United States)

    Okamoto, Eiji; Yano, Tetsuya; Miura, Hidekazu; Shiraishi, Yasuyuki; Yambe, Tomoyuki; Mitamura, Yoshinori

    2017-12-01

    We have developed various axial flow blood pumps to realize the concept of the Valvo pump, and we have studied hemodynamic changes under cardiac assistance using an axial flow blood pump in series with the natural heart. In this study, we measured hemodynamic changes of not only systemic circulation but also cerebral circulation and coronary circulation under cardiac support using our latest axial flow blood pump placed in the descending aorta in an acute animal experiment. The axial flow blood pump was installed at the thoracic descending aorta through a left thoracotomy of a goat (43.8 kg, female). When the pump was on, the aortic pressure and aortic flow downstream of the pump increased with preservation of pulsatilities. The pressure drop upstream of the pump caused reduction of afterload pressure, and it may lead to reduction of left ventricular wall stress. However, cerebral blood flow and coronary blood flow were decreased when the pump was on. The axial flow blood pump enables more effective blood perfusion into systemic circulation, but it has the potential risk of blood perfusion disturbance into cerebral circulation and coronary circulation. The results indicate that the position before the coronary ostia might be suitable for implantation of the axial flow blood pump in series with the natural heart to avoid blood perfusion disturbances.

  13. Measurement of blood flow through surgical anastomosis using the radioactive microsphere technique

    Energy Technology Data Exchange (ETDEWEB)

    Hummel, S.J.; Delgado, G.; Butterfield, A.; Dritschilo, A.; Harbert, J.

    1985-10-01

    Two different radioactive microspheres ( U Ce and UWSc) were used to measure blood flow to an area of the large intestine in dogs before and after a surgical resection was performed with surgical staples. The healing of an anastomosis is theoretically related to the blood flow to the anastomotic site. Blood flow studies were conducted in three dogs using this technique. The average blood flow preoperatively was 0.558 mL/minute per gram and 1.04 mL/minute per gram postoperatively. These results indicate a statistically significant increase in blood flow at the anastomotic site six days after anastomosis when compared with the blood flow to the same area before any surgical procedures.

  14. Measurement of blood flow through surgical anastomosis using the radioactive microsphere technique

    International Nuclear Information System (INIS)

    Hummel, S.J.; Delgado, G.; Butterfield, A.; Dritschilo, A.; Harbert, J.

    1985-01-01

    Two different radioactive microspheres ( 141 Ce and 46 Sc) were used to measure blood flow to an area of the large intestine in dogs before and after a surgical resection was performed with surgical staples. The healing of an anastomosis is theoretically related to the blood flow to the anastomotic site. Blood flow studies were conducted in three dogs using this technique. The average blood flow preoperatively was 0.558 mL/minute per gram and 1.04 mL/minute per gram postoperatively. These results indicate a statistically significant increase in blood flow at the anastomotic site six days after anastomosis when compared with the blood flow to the same area before any surgical procedures

  15. Real-time direct measurement of spinal cord blood flow at the site of compression: relationship between blood flow recovery and motor deficiency in spinal cord injury.

    Science.gov (United States)

    Hamamoto, Yuichiro; Ogata, Tadanori; Morino, Tadao; Hino, Masayuki; Yamamoto, Haruyasu

    2007-08-15

    An in vivo study to measure rat spinal cord blood flow in real-time at the site of compression using a newly developed device. To evaluate the change in thoracic spinal cord blood flow by compression force and to clarify the association between blood flow recovery and motor deficiency after a spinal cord compression injury. Until now, no real-time measurement of spinal cord blood flow at the site of compression has been conducted. In addition, it has not been clearly determined whether blood flow recovery is related to motor function after a spinal cord injury. Our blood flow measurement system was a combination of a noncontact type laser Doppler system and a spinal cord compression device. The rat thoracic spinal cord was exposed at the 11th vertebra and spinal cord blood flow at the site of compression was continuously measured before, during, and after the compression. The functioning of the animal's hind-limbs was evaluated by the Basso, Beattie and Bresnahan scoring scale and the frequency of voluntary standing. Histologic changes such as permeability of blood-spinal cord barrier, microglia proliferation, and apoptotic cell death were examined in compressed spinal cord tissue. The spinal blood flow decreased on each increase in the compression force. After applying a 5-g weight, the blood flow decreased to compression), while no significant difference was observed between the 20-minute ischemia group and the sham group. In the 20-minute ischemia group, the rats whose spinal cord blood flow recovery was incomplete showed significant motor function loss compared with rats that completely recovered blood flow. Extensive breakdown of blood-spinal cord barrier integrity and the following microglia proliferation and apoptotic cell death were detected in the 40-minute complete ischemia group. Duration of ischemia/compression and blood flow recovery of the spinal cord are important factors in the recovery of motor function after a spinal cord injury.

  16. Uteroplacental blood flow measured by placental scintigraphy during epidural anaesthesia for caesarean section

    Energy Technology Data Exchange (ETDEWEB)

    Skjoeldebrand, A.; Eklund, J.; Johansson, H.; Lunell, N.-O.; Nylund, L.; Sarby, B.; Thornstroem, S. (Departments of Anaesthesiology, Obstetrics and Gynaecology and Medical Physics, Karolinska Institute at Huddinge University Hospital, Stockholm (Sweden))

    1990-01-01

    The uteroplacental blood flow was measured before and during epidural anaesthesia for caesarean section in 11 woman. The blood flow was measured with dynamic placental scintigraphy. After an i.v. injection of indium-113m chloride, the gamma radiation over the placenta was recorded with a computer-linked scintillation camera. The uteroplacental blood flow could be calculated from the isotope accumulation curve. The anaesthesia was performed with bupivacaine plain 0.5%, 18-22 ml and a preload of a balanced electrolyte solution 10 ml/kg b.w. was given. The placental blood flow decreased in eight patients and increased in three with a median change of -21%, not being statistically significant. No correlation between maternal blood pressure and placental blood flow was found. (author).

  17. Blood flow measurements during hemodialysis vascular access interventions - Catheter-based thermodilution or Doppler ultrasound?

    DEFF Research Database (Denmark)

    Heerwagen, Søren T; Hansen, Marc A; Schroeder, Torben V

    2012-01-01

    Purpose: To test the clinical performance of catheter-based thermodilution and Doppler ultrasound of the feeding brachial artery for blood flow measurements during hemodialysis vascular access interventions.Methods: Thirty patients with arteriovenous fistulas who underwent 46 interventions had...... access blood flow measured before and after every procedure. Two methods, catheter-based thermodilution and Doppler ultrasound, were compared to the reference method of ultrasound dilution. Catheter-based thermodilution and Doppler ultrasound were performed during the endovascular procedures while flow...

  18. Estimation of intersubject variability of cerebral blood flow measurements using MRI and positron emission tomography

    DEFF Research Database (Denmark)

    Henriksen, Otto Mølby; Larsson, Henrik B W; Hansen, Adam E

    2012-01-01

    PURPOSE: To investigate the within and between subject variability of quantitative cerebral blood flow (CBF) measurements in normal subjects using various MRI techniques and positron emission tomography (PET). MATERIALS AND METHODS: Repeated CBF measurements were performed in 17 healthy, young...

  19. Calf blood flow at rest evaluated by thermal measurement with tissue temperature and heat flow and 133Xe clearance

    International Nuclear Information System (INIS)

    Tamura, Toshiyo; Togawa, Tatsuo; Fukuoka, Masakazu; Kawakami, Kenji.

    1982-01-01

    The regional blood flow in the calf was determined simultaneously by thermal measurement and by 133 Xe clearance technique. Calf blood flow (Ft) by thermal measurement was accounted for by the equation of the form Ft=(CdT*d+Ho-Mb)/rho sub(b)c su b(D) (Ta-Td), where Cd is thermal capacitance of the calf compartment, T*d is the change of calf tissue temperature, Ta is arterila blood temperature, Td is calf tissue temperature, Ho is the heat dissipation from the compartment to the environment, Mb is estimated metabolism of the calf tissue and rho sub(b)c sub(b) is the product of density and specific heat of blood. The healthy men were chosen for the experiments. Total calf blood flow was 2.53+-1.31ml/(min-100ml calf), and muscle blood flow was 2.63+-1.69ml/(min- 100ml muscle) and skin blood flow 7.19+-3.83ml/(min-100ml skin) measured by 133 Xe clearance. On the basis of the results, an estimate has been made of the proportions of the calf volume which can be ascribed to skin and muscle respectively. Estimated muscle and skin blood flow were correlated with total calf blood flow(r=0.98). (author)

  20. Results and validity of renal blood flow measurements using Xenon 133

    International Nuclear Information System (INIS)

    Serres, P.; Danet, B.; Guiraud, R.; Durand, D.; Ader, J.L.

    1975-01-01

    The renal blood flow was measured by external recording of the xenon 133 excretion curve. The study involved 45 patients with permanent high blood pressure and 7 transplant patients. The validity of the method was checked on 10 dogs. From the results it seems that the cortical blood flow, its fraction and the mean flow rate are the most representative of the renal haemodynamics parameters, from which may be established the repercussions of blood pressure on kidney vascularisation. Experiments are in progress on animals to check the compartment idea by comparing injections into the renal artery and into various kidney tissues in situ [fr

  1. Anxiety and cerebral blood flow during behavioral challenge. Dissociation of central from peripheral and subjective measures

    International Nuclear Information System (INIS)

    Zohar, J.; Insel, T.R.; Berman, K.F.; Foa, E.B.; Hill, J.L.; Weinberger, D.R.

    1989-01-01

    To investigate the relationship between anxiety and regional cerebral blood flow, we administered behavioral challenges to 10 patients with obsessive-compulsive disorder while measuring regional cerebral blood flow with the xenon 133 inhalation technique. Each patient was studied under three conditions: relaxation, imaginal flooding, and in vivo (actual) exposure to the phobic stimulus. Subjective anxiety, obsessive-compulsive ratings, and autonomic measures (heart rate, blood pressure) increased significantly, but respiratory rate and PCO 2 did not change across the three conditions. Regional cerebral blood flow increased slightly (in the temporal region) during imaginal flooding, but decreased markedly in several cortical regions during in vivo exposure, when anxiety was highest by subjective and peripheral autonomic measures. These results demonstrate that intense anxiety can be associated with decreased rather than increased cortical perfusion and that ostensibly related states of anxiety (eg, anticipatory and obsessional anxiety) may be associated with opposite effects on regional cerebral blood flow

  2. Anxiety and cerebral blood flow during behavioral challenge. Dissociation of central from peripheral and subjective measures

    Energy Technology Data Exchange (ETDEWEB)

    Zohar, J.; Insel, T.R.; Berman, K.F.; Foa, E.B.; Hill, J.L.; Weinberger, D.R.

    1989-06-01

    To investigate the relationship between anxiety and regional cerebral blood flow, we administered behavioral challenges to 10 patients with obsessive-compulsive disorder while measuring regional cerebral blood flow with the xenon 133 inhalation technique. Each patient was studied under three conditions: relaxation, imaginal flooding, and in vivo (actual) exposure to the phobic stimulus. Subjective anxiety, obsessive-compulsive ratings, and autonomic measures (heart rate, blood pressure) increased significantly, but respiratory rate and PCO/sub 2/ did not change across the three conditions. Regional cerebral blood flow increased slightly (in the temporal region) during imaginal flooding, but decreased markedly in several cortical regions during in vivo exposure, when anxiety was highest by subjective and peripheral autonomic measures. These results demonstrate that intense anxiety can be associated with decreased rather than increased cortical perfusion and that ostensibly related states of anxiety (eg, anticipatory and obsessional anxiety) may be associated with opposite effects on regional cerebral blood flow.

  3. Measurement of regional pulmonary blood volume in patients with increased pulmonary blood flow or pulmonary arterial hypertension

    International Nuclear Information System (INIS)

    Wollmer, P.; Rozcovek, A.; Rhodes, C.G.; Allan, R.M.; Maseri, A.

    1984-01-01

    The effects of chronic increase in pulmonary blood flow and chronic pulmonary hypertension on regional pulmonary blood volume was measured in two groups of patients. One group of patients had intracardiac, left-to-right shunts without appreciable pulmonary hypertension, and the other consisted of patients with Eisenmenger's syndrome or primary pulmonary hypertension, i.e. patients with normal or reduced blood flow and severe pulmonary hypertension. A technique based on positron tomography was used to measure lung density (by transmission scanning) and regional pulmonary blood volume (after inhalation of /sup 11/CO). The distribution of pulmonary blood volume was more uniform in patients with chronic increase in pulmonary blood flow than in normal subjects. There were also indications of an absolute increase in intrapulmonary blood volume by about 15%. In patients with chronic pulmonary arterial hypertension, the distribution of pulmonary blood volume was also abnormally uniform. There was, however, no indication that overall intrapulmonary blood volume was substantially different from normal subjects. The abnormally uniform distribution of pulmonary blood volume can be explained by recruitment and/or dilatation of vascular beds. Intrapulmonary blood volume appears to be increased in patients with intracardiac, left-to-right shunts. With the development of pulmonary hypertension, intrapulmonary blood volume falls, which may be explained by reactive changes in the vasculature and/or obliteration of capillaries

  4. Measuring retinal blood flow in rats using Doppler optical coherence tomography without knowing eyeball axial length

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenzhong; Yi, Ji; Chen, Siyu [Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Jiao, Shuliang [Department of Biomedical Engineering, Florida International University, Miami, Florida 33174 (United States); Zhang, Hao F., E-mail: hfzhang@northwestern.edu [Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208 and Department of Ophthalmology, Northwestern University, Chicago, Illinois 60611 (United States)

    2015-09-15

    Purpose: Doppler optical coherence tomography (OCT) is widely used for measuring retinal blood flow. Existing Doppler OCT methods require the eyeball axial length, in which empirical values are usually used. However, variations in the axial length can create a bias unaccounted for in the retinal blood flow measurement. The authors plan to develop a Doppler OCT method that can measure the total retinal blood flow rate without requiring the eyeball axial length. Methods: The authors measured the retinal blood flow rate using a dual-ring scanning protocol. The small and large scanning rings entered the eye at different incident angles (small ring: 4°; large ring: 6°), focused on different locations on the retina, and detected the projected velocities/phase shifts along the probing beams. The authors calculated the ratio of the projected velocities between the two rings, and then used this ratio to estimate absolute flow velocity. The authors tested this method in both Intralipid phantoms and in vivo rats. Results: In the Intralipid flow phantom experiments, the preset and measured flow rates were consistent with the coefficient of determination as 0.97. Linear fitting between preset and measured flow rates determined the fitting slope as 1.07 and the intercept as −0.28. In in vivo rat experiments, the measured average total retinal blood flow was 7.02 ± 0.31μl/min among four wild-type rats. The authors’ measured flow rates were consistent with results in the literature. Conclusions: By using a dual-ring scanning protocol with carefully controlled incident angle difference between the two scanning rings in Doppler OCT, the authors demonstrated that it is feasible to measure the absolute retinal blood flow without knowing the eyeball axial length.

  5. Measurement of real pulsatile blood flow using X-ray PIV technique with CO2 microbubbles.

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Seo, Seung-Jun; Lim, Jae-Hong; Lee, Sang-Joon

    2015-03-06

    Synchrotron X-ray imaging technique has been used to investigate biofluid flows in a non-destructive manner. This study aims to investigate the feasibility of the X-ray PIV technique with CO2 microbubbles as flow tracer for measurement of pulsatile blood flows under in vivo conditions. The traceability of CO2 microbubbles in a pulsatile flow was demonstrated through in vitro experiment. A rat extracorporeal bypass loop was used by connecting a tube between the abdominal aorta and jugular vein of a rat to obtain hemodynamic information of actual pulsatile blood flows without changing the hemorheological properties. The decrease in image contrast of the surrounding tissue was also investigated for in vivo applications of the proposed technique. This technique could be used to accurately measure whole velocity field information of real pulsatile blood flows and has strong potential for hemodynamic diagnosis of cardiovascular diseases.

  6. Measurement of real pulsatile blood flow using X-ray PIV technique with CO2 microbubbles

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Seo, Seung-Jun; Lim, Jae-Hong; Lee, Sang-Joon

    2015-01-01

    Synchrotron X-ray imaging technique has been used to investigate biofluid flows in a non-destructive manner. This study aims to investigate the feasibility of the X-ray PIV technique with CO2 microbubbles as flow tracer for measurement of pulsatile blood flows under in vivo conditions. The traceability of CO2 microbubbles in a pulsatile flow was demonstrated through in vitro experiment. A rat extracorporeal bypass loop was used by connecting a tube between the abdominal aorta and jugular vein of a rat to obtain hemodynamic information of actual pulsatile blood flows without changing the hemorheological properties. The decrease in image contrast of the surrounding tissue was also investigated for in vivo applications of the proposed technique. This technique could be used to accurately measure whole velocity field information of real pulsatile blood flows and has strong potential for hemodynamic diagnosis of cardiovascular diseases. PMID:25744850

  7. Regional blood flow during exercise in humans measured by near-infrared spectroscopy and indocyanine green

    DEFF Research Database (Denmark)

    Boushel, R; Langberg, Henning; Olesen, J

    2000-01-01

    Using near-infrared spectroscopy (NIRS) and the tracer indocyanine green (ICG), we quantified blood flow in calf muscle and around the Achilles tendon during plantar flexion (1-9 W). For comparison, blood flow in calf muscle was determined by dye dilution in combination with magnetic resonance...... imaging measures of muscle volume, and, for the peritendon region, blood flow was measured by (133)Xe washout. From rest to a peak load of 9 W, NIRS-ICG blood flow in calf muscle increased from 2.4+/-0.2 to 74+/-5 ml x 100 ml tissue(-1) x min(-1), similar to that measured by reverse dye (77+/-6 ml x 100...

  8. A simple technique to measure regional cerebral blood flow during intravascular ballon clamping

    International Nuclear Information System (INIS)

    Furuhata, Shigeru; Kubo, Atsushi; Kawase, Takeshi; Ibata, Yukio; Toya, Shigeo

    1988-01-01

    A case of giant internal carotid ophthalmic aneurysm was presented. In order to clarify whether the patient could tolerate carotid occlusion, a ballon clamping test was performed before surgery. The cerebral blood flow was measured using early imaging by single photon emission computed tomography (SPECT) with N-isopropyl-(iodine-123)-p-iodoamphetamine ( 123 I-IMP). When the ballon clamping test was performed the tracer was injected, and scanning was performed 35 minutes after removing the catheter. This tracer enabled a 'memory of blood flow' during temporary ischemia to determine the character of quick diffusion and slow wash out, that could not be performed by other methods of cerebral blood flow measurement. SPECT with 123 I-IMP can simplify the measurement of cerebral blood flow during the balloon clamping test. (author)

  9. Quantitative blood flow measurements in the small animal cardiopulmonary system using digital subtraction angiography

    International Nuclear Information System (INIS)

    Lin Mingde; Marshall, Craig T.; Qi, Yi; Johnston, Samuel M.; Badea, Cristian T.; Piantadosi, Claude A.; Johnson, G. Allan

    2009-01-01

    Purpose: The use of preclinical rodent models of disease continues to grow because these models help elucidate pathogenic mechanisms and provide robust test beds for drug development. Among the major anatomic and physiologic indicators of disease progression and genetic or drug modification of responses are measurements of blood vessel caliber and flow. Moreover, cardiopulmonary blood flow is a critical indicator of gas exchange. Current methods of measuring cardiopulmonary blood flow suffer from some or all of the following limitations--they produce relative values, are limited to global measurements, do not provide vasculature visualization, are not able to measure acute changes, are invasive, or require euthanasia. Methods: In this study, high-spatial and high-temporal resolution x-ray digital subtraction angiography (DSA) was used to obtain vasculature visualization, quantitative blood flow in absolute metrics (ml/min instead of arbitrary units or velocity), and relative blood volume dynamics from discrete regions of interest on a pixel-by-pixel basis (100x100 μm 2 ). Results: A series of calibrations linked the DSA flow measurements to standard physiological measurement using thermodilution and Fick's method for cardiac output (CO), which in eight anesthetized Fischer-344 rats was found to be 37.0±5.1 ml/min. Phantom experiments were conducted to calibrate the radiographic density to vessel thickness, allowing a link of DSA cardiac output measurements to cardiopulmonary blood flow measurements in discrete regions of interest. The scaling factor linking relative DSA cardiac output measurements to the Fick's absolute measurements was found to be 18.90xCO DSA =CO Fick . Conclusions: This calibrated DSA approach allows repeated simultaneous visualization of vasculature and measurement of blood flow dynamics on a regional level in the living rat.

  10. Quantitative blood flow measurements in the small animal cardiopulmonary system using digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lin Mingde; Marshall, Craig T.; Qi, Yi; Johnston, Samuel M.; Badea, Cristian T.; Piantadosi, Claude A.; Johnson, G. Allan [Department of Radiology, Center for In Vivo Microscopy and Department of Biomedical Engineering, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States); Division of Pulmonary and Critical Care Medicine and Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Box 3823, Durham, North Carolina 27710 (United States); Department of Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States); Department of Radiology, Center for In Vivo Microscopy and Department of Biomedical Engineering, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States); Department of Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States); Division of Pulmonary and Critical Care Medicine and Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Box 3823, Durham, North Carolina 27710 (United States); Department of Radiology, Center for In Vivo Microscopy and Department of Biomedical Engineering, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States)

    2009-11-15

    Purpose: The use of preclinical rodent models of disease continues to grow because these models help elucidate pathogenic mechanisms and provide robust test beds for drug development. Among the major anatomic and physiologic indicators of disease progression and genetic or drug modification of responses are measurements of blood vessel caliber and flow. Moreover, cardiopulmonary blood flow is a critical indicator of gas exchange. Current methods of measuring cardiopulmonary blood flow suffer from some or all of the following limitations--they produce relative values, are limited to global measurements, do not provide vasculature visualization, are not able to measure acute changes, are invasive, or require euthanasia. Methods: In this study, high-spatial and high-temporal resolution x-ray digital subtraction angiography (DSA) was used to obtain vasculature visualization, quantitative blood flow in absolute metrics (ml/min instead of arbitrary units or velocity), and relative blood volume dynamics from discrete regions of interest on a pixel-by-pixel basis (100x100 {mu}m{sup 2}). Results: A series of calibrations linked the DSA flow measurements to standard physiological measurement using thermodilution and Fick's method for cardiac output (CO), which in eight anesthetized Fischer-344 rats was found to be 37.0{+-}5.1 ml/min. Phantom experiments were conducted to calibrate the radiographic density to vessel thickness, allowing a link of DSA cardiac output measurements to cardiopulmonary blood flow measurements in discrete regions of interest. The scaling factor linking relative DSA cardiac output measurements to the Fick's absolute measurements was found to be 18.90xCO{sub DSA}=CO{sub Fick}. Conclusions: This calibrated DSA approach allows repeated simultaneous visualization of vasculature and measurement of blood flow dynamics on a regional level in the living rat.

  11. Dynamic measurements of total hepatic blood flow with Phase Contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yzet, Thierry [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Yzet.Thierry@chu-amiens.fr; Bouzerar, Roger [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: bouzerar.roger@chu-amiens.fr; Baledent, Olivier [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Olivier.Baledent@chu-amiens.fr; Renard, Cedric [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Renard.Cedric@chu-amiens.fr; Lumbala, Didier Mbayo [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: MbayoLumbala.Didier@chu-amiens.fr; Nguyen-Khac, Eric [Mobile Unit of Alcoology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Nguyen-Khac.Eric@chu-amiens.fr; Regimbeau, Jean-Marc [Department of Visceral and Digestive General Surgery, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: regimbeau.jean-marc@chu-amiens.fr; Deramond, H. [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: deramond.herve@chu-amiens.fr; Meyer, Marc-Etienne [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Meyer.Marc-Etienne@chu-amiens.fr

    2010-01-15

    Background/Aims: To measure total hepatic blood flow including portal and proper hepatic artery flows as well as the temporal evolution of the vessel's section during a cardiac cycle. Methods: Twenty healthy subjects, with a mean age of 26 years, were explored. Magnetic resonance imaging blood flow measurements were carried out in the portal vein and the proper hepatic artery. MR studies were performed using a 1.5T imager (General Electric Medical Systems). Gradient-echo 2D Fast Cine Phase Contrast sequences were used with both cardiac and respiratory gatings. Data analysis was performed using a semi-automatic software built in our laboratory. Results: The total hepatic flow rate measured was 1.35 {+-} 0.18 L/min or 19.7 {+-} 4.6 mL/(min kg). The proper hepatic artery provided 19.1% of the total hepatic blood flow entering the liver. Those measurements were in agreement with earlier studies using direct measurements. Mean and maximum velocities were also assessed and a discrepancy between our values and the literature's Doppler data was found. Measurements of the portal vein area have shown a mean variation, defined as a 'pulsatility' index of 18% over a cardiac cycle. Conclusions: We report here proper hepatic artery blood flow rate measurements using MRI. Associated with portal flow measurements, we have shown the feasibility of total hepatic flowmetry using a non-invasive and harmless technique.

  12. Hybrid PIV-PTV technique for measuring blood flow in rat mesenteric vessels.

    Science.gov (United States)

    Ha, Hojin; Nam, Kweon-Ho; Lee, Sang Joon

    2012-11-01

    The micro-particle tracking velocimetry (μ-PTV) technique is used to obtain the velocity fields of blood flow in the microvasculature under in vivo conditions because it can provide the blood velocity distribution in microvessels with high spatial resolution. The in vivo μ-PTV technique usually requires a few to tens of seconds to obtain a whole velocity profile across the vessel diameter because of the limited number density of tracer particles under in vivo conditions. Thus, the μ-PTV technique alone is limited in measuring unsteady blood flows that fluctuate irregularly due to the heart beating and muscle movement in surrounding tissues. In this study, a new hybrid PIV-PTV technique was established by combining PTV and particle image velocimetry (PIV) techniques to resolve the drawbacks of the μ-PTV method in measuring blood flow in microvessels under in vivo conditions. Images of red blood cells (RBCs) and fluorescent particles in rat mesenteric vessels were obtained simultaneously. Temporal variations of the centerline blood velocity were monitored using a fast Fourier transform-based cross-correlation PIV method. The fluorescence particle images were analyzed using the μ-PTV technique to extract the spatial distribution of the velocity vectors. Data from the μ-PTV and PIV methods were combined to obtain a better estimate of the velocity profile in actual blood flow. This technique will be useful in investigating hemodynamics in microcirculation by measuring unsteady irregular blood flows more accurately. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Blood viscoelasticity measurement using steady and transient flow controls of blood in a microfluidic analogue of Wheastone-bridge channel

    Science.gov (United States)

    Jun Kang, Yang; Lee, Sang-Joon

    2013-01-01

    Accurate measurement of blood viscoelasticity including viscosity and elasticity is essential in estimating blood flows in arteries, arterials, and capillaries and in investigating sub-lethal damage of RBCs. Furthermore, the blood viscoelasticity could be clinically used as key indices in monitoring patients with cardiovascular diseases. In this study, we propose a new method to simultaneously measure the viscosity and elasticity of blood by simply controlling the steady and transient blood flows in a microfluidic analogue of Wheastone-bridge channel, without fully integrated sensors and labelling operations. The microfluidic device is designed to have two inlets and outlets, two side channels, and one bridge channel connecting the two side channels. Blood and PBS solution are simultaneously delivered into the microfluidic device as test fluid and reference fluid, respectively. Using a fluidic-circuit model for the microfluidic device, the analytical formula is derived by applying the linear viscoelasticity model for rheological representation of blood. First, in the steady blood flow, the relationship between the viscosity of blood and that of PBS solution (μBlood/μPBS) is obtained by monitoring the reverse flows in the bridge channel at a specific flow-rate rate (QPBSSS/QBloodL). Next, in the transient blood flow, a sudden increase in the blood flow-rate induces the transient behaviors of the blood flow in the bridge channel. Here, the elasticity (or characteristic time) of blood can be quantitatively measured by analyzing the dynamic movement of blood in the bridge channel. The regression formula (ABlood (t) = Aα + Aβ exp [−(t − t0)/λBlood]) is selected based on the pressure difference (ΔP = PA − PB) at each junction (A, B) of both side channels. The characteristic time of bloodBlood) is measured by analyzing the area (ABlood) filled with blood in the bridge channel by selecting an appropriate detection window in the

  14. New possibilities for quantitative measurements of regional cerebral blood flow with gold-195m

    International Nuclear Information System (INIS)

    Lindner, P.; Nickel, O.

    1985-01-01

    A previously reported theory for quantitative cerebral blood flow measurement for nondiffusible radiotracers has been applied to patients after stroke and to volunteers undergoing a mental stimulation exercise. The energy spectrum of gold-195m shows two strong photon peaks, one at an energy level of 68 keV and a second at an energy-level of 262 keV. The low energy peak is suitable for perfusion studies in lateral views of the hemispheres; no look-through effect is seen. The high energy level is good for studies in posterior-anterior positions. Parametric images for quantitative regional cerebral blood flow can be generated. The area of occluded vessels in the case of stroke can be detected. Quantitative activation patterns of cerebral blood flow during mental stimulation can be generated. The results prove that, not only with freely diffusible indicators like xenon but also with nondiffusible indicators, it is possible to measure quantitatively cerebral blood flow patterns

  15. Measurements of blood flow to individual glomeruli in the ophidian kidney.

    Science.gov (United States)

    Yokota, S D; Dantzler, W H

    1990-06-01

    Continuous measurements of the instantaneous rate of blood flow to individual glomeruli in a normal vertebrate kidney were made in the garter snake Thamnophis sirtalis. Epifluorescence video microscopy was used to visualize and record blood flow in the afferent arterioles of superficial nephrons. The dual-slit method was used for the determination of red blood cell (RBC) velocity from the video replay. Simultaneous measurements of the vessel diameter allowed the continuous determination of the instantaneous rate of blood flow. A total of 100 glomeruli was surveyed in 12 animals. These glomeruli displayed both constant and highly variable rates of blood flow, with 21% of all nephrons displaying intermittent glomerular perfusion. The mean single-nephron blood flow rate (SNBFR) for all individuals was 23.9 +/- 10.3 (SD) nl/min (n = 12). The percentage of nephrons with intermittent flow for an individual animal increased significantly with increasing plasma osmolality. Intermittency was associated with low SNBFR values; SNBFR averaged 13.5 +/- 10.2 (SD) nl/min (n = 21) in intermittent nephrons and 29.2 +/- 19.0 (SD) nl/min (n = 79) in continuous flow nephrons, the difference being significant (P less than 0.001). Nephrons with continuous perfusion displayed a much greater range of SNBFR values than intermittent nephrons. This suggests that, although changes in whole kidney glomerular filtration rate (GFR) in reptiles need not involve glomerular intermittency, intermittency may lower GFR.

  16. Comparative study of methods for blood flow measurement within transverse sinuses by using MR

    International Nuclear Information System (INIS)

    Gao Gejun; Feng Xiaoyuan; Yang Bojie; Geng Daoying

    2003-01-01

    Objective: To assess the accuracy of two-dimensional phase contrast (2D-PC) MR method for blood flow measurement within transverse sinuses by comparing this method with cine phase contrast (cine-PC) MR and Doppler in volunteers and patients. Methods: (1) A total of 12 transverse sinuses were examined in 8 healthy volunteers. 2D-PC MR and cine-PC MR were used respectively to measure the transverse area of flow, the flow velocities, and the volumetric flow rates in the same position in every transverse sinus. Paired t-test was used for comparison between the results determined by 2D-PC MR and that determined by cine-PC MR. (2) A total of 6 transverse sinuses were examined in 5 patients who needed operation. 2D-PC MR was used to determine the blood flow velocity of transverse sinus before operation, and Doppler was used to determine the blood flow velocity of the same transverse sinus during operation. The linear regression analysis was used for statistical analysis. Results: (1) Statistical analysis indicated that there were no significant difference among the transverse area of flow (t = -1.106, P = 0.293), the flow velocities (t = 0.262, P = 0.798), and the volumetric flow rates (t = 0.439, P = 0.669) measured by using 2D-PC MR and cine PC MR, respectively. (2) The correlation between flow velocities determined by 2D-PC MR imaging before operation and that determined by Doppler during operation was in excellent agreement (Y-circumflex = 1.303 x + 0.62, r 2 = 0.88). Conclusion: 2D-PC MR may be a practical convenient method for blood flow measurement within transverse sinuses system

  17. Quantitative measurement of the blood flow in peripheral vascular diseases by a new radionuclide plethysmography

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, K.; Mori, Y.; Mashima, Y.; Shimada, T.; Fukuoka, M.

    1985-05-01

    The purpose of the study is to introduce a new plethysmography using radionuclide (RN) for a quantitative measurement of the blood flow in the extremities following the routine RN angiography. Seventy five patients with various peripheral artery diseases have been examined. RN pletysmography was performed in the supine position 15 min. after the RN angiography using 15 mCi of Tc-99m RBC. The blood flow (F) was calculated by the equation (1) which consists of three parameters, the initial slope of the time-activity curve (dc/dt*t=0) after the venous occlusion on the thigh, changes of radio-activity (C-Co) before and after avascularization by inflation of cuff with 200 mmHg pressure at calf, and the blood volume per unit tissue volume (..beta..=Vb/V,ml/100g tissue). F (ml/min/100g) = ..beta.. (dc/dt*t=0)/C-Co. The blood flow measured simultaneously by RN plethysmography and admittance plethysmography was significantly correlated (r = 0.906,n = 16). The blood flow in 67 normal subjects was 2.78 +- 0.75 ml/min/100g. In the patients with intermittent claudication the blood flow was decreased (1.89 +- 0.75 ml/min/100g,n = 75). In the cases with poorly developed colateral circulation the blood flow markedly decreased (1.62 +- 0.29 ml/min/100g,n = 10). Increases of blood flow after exercise was small in the cases with stenosis, even in patients with collaterals. This method is very useful to evaluate quantitatively the peripheral hemodynamics following the routine RN angiographic examination.

  18. Methods for measurement of cerebral blood flow in man

    DEFF Research Database (Denmark)

    Lassen, N A

    1976-01-01

    -cerebral uptake, and insensitive both for detecting regional ischemia and regional hyperemia. The spatial resolution is also much more limited. For these reasons great caution must be exercised in interpreting the results. Methods yielding three-dimensional rCBF data will be needed in order to gain more precise...... information both on spatial localization and, especially, on ischemic areas. The most promising is computer-assisted axial tomography with freely diffusible radioactive isotopes or with x-rays using an intra-arterial injection of contrast. But, the available techniques are still too slow: in order to measure...

  19. In vivo lateral blood flow velocity measurement using speckle size estimation.

    Science.gov (United States)

    Xu, Tiantian; Hozan, Mohsen; Bashford, Gregory R

    2014-05-01

    In previous studies, we proposed blood measurement using speckle size estimation, which estimates the lateral component of blood flow within a single image frame based on the observation that the speckle pattern corresponding to blood reflectors (typically red blood cells) stretches (i.e., is "smeared") if blood flow is in the same direction as the electronically controlled transducer line selection in a 2-D image. In this observational study, the clinical viability of ultrasound blood flow velocity measurement using speckle size estimation was investigated and compared with that of conventional spectral Doppler of carotid artery blood flow data collected from human patients in vivo. Ten patients (six male, four female) were recruited. Right carotid artery blood flow data were collected in an interleaved fashion (alternating Doppler and B-mode A-lines) with an Antares Ultrasound Imaging System and transferred to a PC via the Axius Ultrasound Research Interface. The scanning velocity was 77 cm/s, and a 4-s interval of flow data were collected from each subject to cover three to five complete cardiac cycles. Conventional spectral Doppler data were collected simultaneously to compare with estimates made by speckle size estimation. The results indicate that the peak systolic velocities measured with the two methods are comparable (within ±10%) if the scan velocity is greater than or equal to the flow velocity. When scan velocity is slower than peak systolic velocity, the speckle stretch method asymptotes to the scan velocity. Thus, the speckle stretch method is able to accurately measure pure lateral flow, which conventional Doppler cannot do. In addition, an initial comparison of the speckle size estimation and color Doppler methods with respect to computational complexity and data acquisition time indicated potential time savings in blood flow velocity estimation using speckle size estimation. Further studies are needed for calculation of the speckle stretch method

  20. Experimental validation of uterine artery volume blood flow measurement by Doppler ultrasonography in pregnant sheep.

    Science.gov (United States)

    Acharya, G; Sitras, V; Erkinaro, T; Mäkikallio, K; Kavasmaa, T; Päkkilä, M; Huhta, J C; Räsänen, J

    2007-04-01

    To test the hypothesis that Doppler-derived (calculated) uterine artery volume blood flow (cQ(UtA)) reflects accurately volume blood flow measured directly (mQ(UtA)) in an experimental setting. Five pregnant sheep were instrumented at 122-130 days of gestation under general anesthesia. After a 4-day recovery period, maternal hemodynamics were varied by administering to the sheep under general anesthesia noradrenaline, beta-blocker, low oxygen gas mixture, epidural bupivacaine and ephedrine, consecutively. The central venous pressure was obtained with the help of a thermodilution catheter. The mean arterial pressure and acid-base status were monitored using a 16-gauge polyurethane catheter inserted into the descending aorta via a femoral artery. A 6-mm transit-time ultrasonic perivascular flow probe was used to measure the mQ(UtA). Doppler ultrasonography of the uterine artery was performed and volume blood flow was obtained simultaneously by the transit-time ultrasonic perivascular flow probe during each phase of the experiment. A total of 31 observations were made. The mQ(UtA) varied between 90 and 800 (mean +/- SD, 419 +/- 206) mL/min during the experiments. The corresponding values for the cQ(UtA) were 110 and 900 (mean +/- SD, 459 +/- 211) mL/min. There was a significant correlation (R = 0.76; P blood flow measured directly. Doppler-derived uterine artery absolute blood flow velocities reflect uteroplacental volume blood flow in pregnant sheep. Published by John Wiley & Sons, Ltd. Copyright (c) 2007 ISUOG.

  1. Glucose Pump Test can be Used to Measure Blood Flow Rate of ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Methods: In 93 chronic hemodialysis patients with native AV fistula, blood flow rates were measured by Doppler US and GPT. For GPT, glucose was infused to 16 mL/min by pump and was measured at basal before the infusion and 11 s after the start of ... Doppler US is expensive and time consuming,.

  2. New possibilities for quantitative measurements of regional cerebral blood flow with Au-195 m

    International Nuclear Information System (INIS)

    Lindner, P.; Nickel, O.

    1984-01-01

    A previously reported theory for quantitative cerebral blood flow measurement for nondiffusible radiotracers has been applied on patients after stroke and an volunteers undergoing a mental stimulation exercise. Quantitative measurements of cerebral blood flow patterns not only in p-a. but also in lateral views of the brain are possible by the use of the recently developed generator for the short lived (30 sec) isotope Au-195 m. The energy spectrum of the eluate of the generator shows two strong photon peaks, one at an energy level of 68 KeV and a second at an energy-level of 262 KeV. The low energy peak is suitable for perfusion studies in lateral views of the hemispheres, no ''look through'' effect is seen. The high energy level is good for studies in p-a-positions. The studies last less than 1 minute and can be repeated after 3 minutes. Parametric images for quantitative regional cerebral blood flow can be generated. The area of occluded vessels in the case of stroke can be detected. Quantitative activation patterns of cerebral blood flow during mental stimulation can be generated. The results prove that not only with freely diffusible indicators like Xenon but also with nondiffusible indicators it is possible to measure quantitatively cerebral blood flow patterns. (orig.)

  3. Cerebral blood flow measured by positron emission tomography during normothermic cardiopulmonary bypass: an experimental porcine study.

    Science.gov (United States)

    Thomassen, Sisse Anette; Kjærgaard, Benedict; Alstrup, Aage Kristian Olsen; Munk, Ole Lajord; Frøkiær, Jørgen; Larsson, Anders; Rasmussen, Bodil Steen

    2018-01-01

    Mean arterial blood pressure (MAP) and/or pump flow during normothermic cardiopulmonary bypass (CPB) are the most important factors of cerebral perfusion. The aim of this study was to explore the influence of CPB blood flow on cerebral blood flow (CBF) measured by dynamic positron emission tomography (PET) using 15 O-labelled water with no pharmacological interventions to maintain the MAP. Eight pigs (69-71 kg) were connected to normothermic CPB. After 60 minutes (min) with a CPB pump flow of 60 mL/kg/min, the pigs were changed to either 35 mL/kg/min or 47.5 mL/kg/min for 60 min and, thereafter, all the pigs returned to 60 mL/kg/min for another 60 min. The MAP was measured continuously and the CBF was measured by positron emission tomography (PET) during spontaneous circulation and at each CPB pump flow after 30 min of steady state. Two pigs were excluded due to complications. CBF increased from spontaneous circulation to a CPB pump flow of 60 mL/kg/min. A reduction in CPB pump flow to 47.5 mL/kg/min (n=3) resulted in only minor changes in CBF while a reduction to 35 mL/kg/min (n=3) caused a pronounced change (correlation coefficient (R 2 ) 0.56). A return of CPB pump flow to 60 mL/kg/min was followed by an increase in CBF, except in the one pig with the lowest CBF during low flow (R 2 =0.44). CBF and MAP were not correlated (R 2 =0.20). In this experimental porcine study, a relationship was observed between pump flow and CBF under normothermic low-flow CPB. The effect of low pump flow on MAP showed substantial variations, with no correlation between CBF and MAP.

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  5. Improvement of the accuracy of continuous hematocrit measurement under various blood flow conditions

    Science.gov (United States)

    Kim, Myounggon; Yang, Sung

    2014-04-01

    We propose an accurate method for continuous hematocrit (HCT) measurement of flowing blood under varying plasma conditions of electrical conductivity, osmolality, and flow rate. Two parameters, namely the hematocrit estimation parameter (HEP) and normalized difference, are proposed to reduce the HCT measurement error. HEP was demonstrated in a previous work. The results of multiple linear regression analysis showed that the two parameters were strongly correlated with the reference HCT measured by microcentrifugation. The measurement error was less than 9% despite significant simultaneous variations in the plasma properties and shear rate.

  6. [Measurement of the blood flow in various areas of the rat brain by means of microspheres].

    Science.gov (United States)

    Deroo, J; Gerber, G B

    1976-01-01

    A method is described to measure regional blood flow in different structures of the rat brain. Microspheres (15 micron) are injected, the brain is sectioned, stained for myeline, radioautographs are prepared and the microspheres in the different structures are counted. The values obtained for different brain structures are counted. The values obtained for different brain regions (cortex, corpus callosum, thalamus hipocampus, hypothalamic region, colliculi, cerebellum, pons, medulla) compare well with those published by others on larger animals. In rats fed 1% of lead from birth, higher blood flow is found in the cortex and a lower one in the interior part of the brain compared to controls.

  7. Skin blood flow in humans as a function of environmental temperature measured by ultrasound.

    Science.gov (United States)

    Thoresen, M; Walløe, L

    1980-07-01

    We have measured the blood velocities in arteries supplying the skin in humans both in areas with arteriovenous anastomoses (AVA) and in skin areas without AVA in different temperature situations by means of a pulsed, bidirectional doppler ultrasound instrument. The instrument measures the time average of the instantaneous mean of the blood velocities present in a cross-section of a vessel. So long as the cross-sectional area of the vessel is constant, this average velocity is proportional to volume flow. We observe rapid and large fluctuations in blood velocities in arteries supplying skin areas with AVA in a comfortably warm environment. These fluctuations are substantially larger and more rapid than described by previous authors who have used plethysmograph methods. The blood velocities are more constant both at higher and lower environmental temperatures. There are no similar fluctuations in blood velocity in arteries supplying skin areas without AVA.

  8. CALF BLOOD-FLOW AND POSTURE - DOPPLER ULTRASOUND MEASUREMENTS DURING AND AFTER EXERCISE

    NARCIS (Netherlands)

    VANLEEUWEN, BE; BARENDSEN, GJ; LUBBERS, J; DEPATER, L

    To investigate the joint effects of body posture and calf muscle pump, the calf blood flow of eight healthy volunteers was measured with pulsed Doppler equipment during and after 3 min of rhythmic exercise on a calf ergometer in the supine, sitting, and standing postures. Muscle contractions

  9. Glucose Pump Test can be Used to Measure Blood Flow Rate of ...

    African Journals Online (AJOL)

    The aim of study is to determine whether glucose pump test (GPT) is used for surveillance of native AV fistulas by using Doppler US as reference. Methods: In 93 chronic hemodialysis patients with native AV fistula, blood flow rates were measured by Doppler US and GPT. For GPT, glucose was infused to 16 mL/min by ...

  10. Development of dual micro-PIV system for simultaneous velocity measurements: optical arrangement techniques and application to blood flow measurements

    International Nuclear Information System (INIS)

    Kvon, Alexandr; Lee, Yeon Ho; Cheema, Taqi Ahmad; Park, Cheol Woo

    2014-01-01

    Blood rheological characteristics can significantly vary with the motion of red blood cells (RBCs) in plasma. Moreover, RBCs show a complicated behavior in micro vessels. Thus, the determination of either plasma or blood cell velocity distribution has been the primary objective in blood flow analysis. However, the conditions during blood flow analyses are different from the actual physiological conditions, wherein the motion of the two distinct blood phases simultaneously occurs. In this study, we used an in vitro micro-particle image velocimetry, which is a reliable velocity field measurement technique, to evaluate the velocity distribution of plasma and blood cells simultaneously. Blood flow through a rectangular microchannel was determined using special optical filter arrangements and by assuming two different hematocrit values. Using the proposed technique, the averaged parabolic velocity profiles for the RBCs and plasma were successfully obtained and compared. The developed simultaneous measurement technique can be used to predict blood cell and plasma behaviors simultaneously with high accuracy under given clinical conditions. (paper)

  11. Comparison of near-infrared spectroscopy with CT cerebral blood flow measurements in newborn piglets

    Science.gov (United States)

    Brown, Derek W.; Picot, Paul A.; Springett, Roger; Delpy, David T.; Lee, Ting-Yim

    2001-05-01

    Severely premature infants are often at high risk of cerebral hemorrhage or ischemic injury due to their inability to properly regulate blood flow to the brain. If blood flow is too high, the infant is at risk of cerebral hemorrhage, while too little blood flow can result in ischemic injury. The purpose of this research is to design and develop a means of non-invasively measuring cerebral blood flow (CBF) with near infrared spectroscopy (NIRS). Such a device would greatly aid the diagnosis and monitoring of afflicted infants. Previous attempts to measure CBF with NIRS have achieved limited success. In this study we acquired high signal-to-noise NIR spectrum from 600 to 980 nm with a cooled CCD spectrometer. This spectrometer enables the differential path length factor (DPF) to be estimated with accuracy using a second derivative technique described by Matcher et al. The validity of our new approach is determined via direct comparison with a previously validated computed tomography (CT) method. Three newborn piglets were studied. CBF measurements were performed at various partial arterial CO2 tensions (PaCO2) using both the NIRS and CT methods. The results of the two methods correlate well with a relationship of CBFCT equals -4.30 + 1.05 CBFNIRS (r2 equals 0.96).

  12. Cerebral blood flow measured by positron emission tomography during normothermic cardiopulmonary bypass: An experimental porcine study

    DEFF Research Database (Denmark)

    Thomassen, Sisse Anette; Kjaergaard, Benedict; Alstrup, Aage Kristian Olsen

    2018-01-01

    min and, thereafter, all the pigs returned to 60 mL/kg/min for another 60 min. The MAP was measured continuously and the CBF was measured by positron emission tomography (PET) during spontaneous circulation and at each CPB pump flow after 30 min of steady state. Results: Two pigs were excluded due...... emission tomography (PET) using 15O-labelled water with no pharmacological interventions to maintain the MAP. Methods: Eight pigs (69-71 kg) were connected to normothermic CPB. After 60 minutes (min) with a CPB pump flow of 60 mL/kg/min, the pigs were changed to either 35 mL/kg/min or 47.5 mL/kg/min for 60......Background: Mean arterial blood pressure (MAP) and/or pump flow during normothermic cardiopulmonary bypass (CPB) are the most important factors of cerebral perfusion. The aim of this study was to explore the influence of CPB blood flow on cerebral blood flow (CBF) measured by dynamic positron...

  13. Measurement of local cerebral blood flow with Indo (14C) antipyrine. [/sup 131/I, rats, cats

    Energy Technology Data Exchange (ETDEWEB)

    Sakurada, O.; Kennedy, C.; Jehle, J.; Brown, J.D.; Carbin, G.L.; Sokoloff, L.

    1978-01-01

    The autoradiographic diffusible tracer technique for the measurement of local cerebral blood flow was originally designed for use with the radioactive, inert gas /sup 131/I-labeled trifluoroiodomethane and is applicable only with tracers that exhibit unrestricted diffusion through the blood-brain barrier. Because of the technical problems associated with the use of gaseous tracers, a suitable nonvolatile tracer has been sought. (/sup 14/C)-antipyrine has been used previously and found to be unsuitable because of limitations in its diffusion through the blood-brain barrier. An analogue of (/sup 14/C)-antipyrine, iodo-(/sup 14/C)-antipyrine, exhibits higher partition coefficients than (/sup 14/C)-antipyrine between nonpolar solvents and water and might, therefore, be expected to diffuse more freely through the barrier. Its use as the tracer in the local blood flow technique leads to values considerably above those obtained with (/sup 14/C)-antipyrine in the rat and cat and essentially the same as those obtained with the gas trifluoro-(/sup 131/I)-iodomethane in the cat. Iodo-(/sup 14/C)-antipyrine appears, therefore, to be a satisfactory nonvolatile tracer for the measurement of local cerebral blood flow.

  14. Measurement of peripheral blood flow in patients with peripheral artery disease: Methods and considerations.

    Science.gov (United States)

    Salisbury, Dereck L; Brown, Rebecca Jl; Bronas, Ulf G; Kirk, Laura N; Treat-Jacobson, Diane

    2018-02-01

    Peripheral artery disease (PAD) is a manifestation of generalized atherosclerosis which results in hemodynamic compromise of oxygen and substrate delivery to the lower extremity skeletal muscles. Hemodynamic assessments are vital in PAD diagnosis and in the evaluation of strategies aimed at treating claudication (i.e. exercise training, revascularization, and pharmacological agents). Venous occlusion plethysmography (VOP) is a century-old, non-invasive technique used to quantify limb blood flow and has been used to evaluate hemodynamic compromise in patients with PAD. However, the literature suggests a wide array of methodological variability in the measurement and analysis of limb blood flow using VOP. In this manuscript, we overview the clinical application of VOP measurement, and secondly we review the methodological variation that occurs during the measurement and analysis of VOP in healthy individuals and in patients with claudication.

  15. Measurement of utero-placental blood flow with /sup 113m/In in diabetic pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Semmler, K.; Kirsch, G.; Zoellner, P.; Fuhrmann, K.; Jutzi, E. (Zentralinstitut fuer Diabetes, Karlsburg (German Democratic Republic); Ernst-Moritz-Arndt-Universitaet, Greifswald (German Democratic Republic). Radiologische Klinik)

    1985-01-01

    In 122 diabetic pregnancies the placental blood flow has been estimated determining the half-life of the activity inflow (2 MBq /sup 113m/In-transferrin) into the placenta. A highly sensitive detector (modified pinhole collimator) and a computer-supported evaluation were used. 259 flow measurements were compared to the risk of complication in the course of diabetic pregnancy. The half-life values in the diabetic group, calculated by a gamma camera computer system by means of an iterative regression analysis, were significantly different compared to a control group (12 pregnancies without risk.) Severe diabetic angiopathic complications (classes D, F, and R according to White) are accompanied by higher half-life values (placental blood flow reductions) and perinatal complications. Even in pregnant women with gestational diabetes of disturbances of the carbohydrate metabolism disturbed placental hemodynamics is to be found.

  16. Measurement of utero-placental blood flow with /sup 113m/In in diabetic pregnancy

    International Nuclear Information System (INIS)

    Semmler, K.; Kirsch, G.; Zoellner, P.; Fuhrmann, K.; Jutzi, E.; Ernst-Moritz-Arndt-Universitaet, Greifswald

    1985-01-01

    In 122 diabetic pregnancies the placental blood flow has been estimated determining the half-life of the activity inflow (2 MBq /sup 113m/In-transferrin) into the placenta. A highly sensitive detector (modified pinhole collimator) and a computer-supported evaluation were used. 259 flow measurements were compared to the risk of complication in the course of diabetic pregnancy. The half-life values in the diabetic group, calculated by a gamma camera computer system by means of an iterative regression analysis, were significantly different compared to a control group (12 pregnancies without risk.) Severe diabetic angiopathic complications (classes D, F, and R according to White) are accompanied by higher half-life values (placental blood flow reductions) and perinatal complications. Even in pregnant women with gestational diabetes of disturbances of the carbohydrate metabolism disturbed placental hemodynamics is to be found. (author)

  17. Blood flow to palatal mucosal grafts in mandibular labial vestibuloplasty measured by 133Xe clearance technique

    International Nuclear Information System (INIS)

    Basa, S.; Ercan, M.T.; Aras, T.; Araz, K.

    1987-01-01

    In 11 subjects, the blood flow to alveolar and palatal mucosa was measured by intra-mucosal injection of 133 Xe. Later, mandibular labial vestibuloplasty was performed with mucosal grafts in all of them. The use of a stent was omitted. The subjects were followed by clinical observation and by blood flow measurements up to 6 weeks postoperatively. At certain intervals (3 and 10 days, 4 and 6 weeks), 133 Xe clearance in the graft was determined. Under normal conditions, the mean blood flows to the alveolar and to palatal mucosa were 53.2±12.9 and 58.3±3.5 ml/100 g/min, respectively. The difference between them was statistically insignificant (P>0.05). The graft blood flow was 13.4±3.2 and 21.7±15.0 ml/100 g/min on the 3rd and 10th days after operation. The decrease in both compared to normal values was statistically significant (P<0.001). The blood flow reached almost normal levels (46.2±16.9 ml/100 g/min) and above (63.9±9.7 ml/100 g/min; P<0.05) at 4 and 6 weeks after operation, respectively. These results were in agreement with the clinical observations. The palatal donor area healed in 3-5 weeks. The graft showed complete adaptation with the surrounding tissue and healing in 4-6 weeks. Our results also indicated that injections in the graft do not retard graft healing. (author)

  18. Pulse Oximeter Derived Blood Pressure Measurement in Patients With a Continuous Flow Left Ventricular Assist Device.

    Science.gov (United States)

    Hellman, Yaron; Malik, Adnan S; Lane, Kathleen A; Shen, Changyu; Wang, I-Wen; Wozniak, Thomas C; Hashmi, Zubair A; Munson, Sarah D; Pickrell, Jeanette; Caccamo, Marco A; Gradus-Pizlo, Irmina; Hadi, Azam

    2017-05-01

    Currently, blood pressure (BP) measurement is obtained noninvasively in patients with continuous flow left ventricular assist device (LVAD) by placing a Doppler probe over the brachial or radial artery with inflation and deflation of a manual BP cuff. We hypothesized that replacing the Doppler probe with a finger-based pulse oximeter can yield BP measurements similar to the Doppler derived mean arterial pressure (MAP). We conducted a prospective study consisting of patients with contemporary continuous flow LVADs. In a small pilot phase I inpatient study, we compared direct arterial line measurements with an automated blood pressure (ABP) cuff, Doppler and pulse oximeter derived MAP. Our main phase II study included LVAD outpatients with a comparison between Doppler, ABP, and pulse oximeter derived MAP. A total of five phase I and 36 phase II patients were recruited during February-June 2014. In phase I, the average MAP measured by pulse oximeter was closer to arterial line MAP rather than Doppler (P = 0.06) or ABP (P < 0.01). In phase II, pulse oximeter MAP (96.6 mm Hg) was significantly closer to Doppler MAP (96.5 mm Hg) when compared to ABP (82.1 mm Hg) (P = 0.0001). Pulse oximeter derived blood pressure measurement may be as reliable as Doppler in patients with continuous flow LVADs. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  19. Measurement of blood flow in the carotid arteries using color doppler in healthy Korean adults

    International Nuclear Information System (INIS)

    Moon, Ki Ho; Jeon, Do Ig; Choi, Chang Ho; Ro, Young Jin; Kim, Hak Jin; Lee, Suck Hong; Kim, Byung Soo

    1994-01-01

    To evaluate the blood flow patterns and velocities of the carotid arteries in healthy Korean adults. We evaluated the blood flow patterns and measured the peak systolic and end-diastolic velocities of the common, internal and external carotid arteries in 48 healthy adults who did not have cardiovascular disorders and neck lesions. The velocity difference was analyzed according to different age groups. In addition, peak systolic and end-diastolic velocity ratio of the internal to common carotid artery was estimated, and our data were compared with values reported by other authors. Generally, the velocity in the younger age group tends be to higher than in older group. The peak systolic and end diastolic velocities of the internal carotid artery were 84.5 cm/sec and 30.5 cm/sec. The peak systolic and end diastolic velocity ratio of the internal to common carotid artery were 0.715 and 0.966. The internal carotid artery was less resistant in blood flow than the external carotid artery. Our data were lower than the values which were reported by Bluth et al. The blood flow velocities of the internal carotid artery in healthy adults were lower than those of previous reported foreign values, but the patterns were similar

  20. [Digital blood flow measurement by venous occlusion plethysmography in Raynaud's phenomenon. Value of the rewarming test].

    Science.gov (United States)

    Cristol, R; Debray, J

    1986-01-01

    The fingertip blood flow measured by mercury strain gauge plethysmography with venous occlusion, at 22 degrees C room temperature, had significantly lower mean values in 190 patients with Raynaud's phenomenon (55 men aged 49 yrs +/- 16, 135 women aged 48 yrs +/- 16) than in 40 age and sex matched controls: 18 ml/100 ml/minute +/- 14.6 versus 35 ml/100 ml/minute +/- 15 at level p less than 0.01. The mean fingertip blood flow was significantly lower (p less than 0.01) in 31 cases of scleroderma and 32 cases of pulpar necrosis (respectively 13 ml +/- 13 and 11 ml +/- 8) than in 55 cases of primary Raynaud's disease (no detectable etiology and normal capillaroscopy 5 years after onset) or in 34 cases of mild Raynaud's phenomenon (respectively 21.6 +/- 16 and 24.4 +/- 18). A warming test (both hands in water at 45 degrees C during 3 minutes) was performed in 50 cases with low basal fingertip blood flow. It induced a "normalized" flow in 22 cases (mostly primary or mild Raynaud), a partly improved flow in 20 cases (mostly secondary Raynaud) and no improvement in 8 cases (scleroderma). The warming test appears to be clinically useful to assess the vasospasm and the vasodilating capabilities.

  1. Measurement of regional cerebral blood flow by intravenous administation of 133 xenon

    International Nuclear Information System (INIS)

    Ryding, E.

    1986-01-01

    Reviewing the background and the theory for rCFB measurements the following conditions are established for the use of flow measurement with 133-Xenon as a reliable indicator for indirect measurements of cerebral functional activity. 1. There is a strict coupling between rCBF and regional metabolism. This condition can only be considered to be fulfilled in the normal non-anoxic bran tissue. 2. There is a close correlation between the tissue and the venous concentration of 133-Xenin which can be reliably approximated by the blood-brain partition coefficient. This condition can be considered to be fullfilled in the normal flow range, but not in pathological conditions such as cerebrovascular occlusions. 3. Intercompartment diffusion of 133-Xenon has no significant effect upon the measurement of rCBF values. This condition appear to share its limitations for fulfilement with condition 2. 4. There is no significant contamination by the extracerebral flow components at IH or IV rCBF measurements. 5. There is a negligible 'look through' effect from surrounding areas to region with focal high or low blood flow. (U.W.)

  2. X-ray PIV measurement of blood flow in deep vessels of a rat: An in vivo feasibility study.

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Lee, Sang Joon

    2016-01-18

    X-ray PIV measurement is a noninvasive approach to measure opaque blood flows. However, it is not easy to measure real pulsatile blood flows in the blood vessels located at deep position of the body, because the surrounding tissues significantly attenuate the contrast of X-ray images. This study investigated the effect of surrounding tissues on X-ray beam attenuation by measuring the velocity fields of blood flows in deep vessels of a live rat. The decrease in image contrast was minimized by employing biocompatible CO2 microbubbles as tracer particles. The maximum measurable velocity of blood flows in the abdominal aorta of a rat model was found through comparative examination between the PIV measurement accuracy and the level of image contrast according to the input flow rate. Furthermore, the feasibility of using X-ray PIV to accurately measure in vivo blood flows was demonstrated by determining the velocity field of blood flows in the inferior vena cava of a rat. This study may serve as a reference in conducting in vivo X-ray PIV measurements of pulsatile blood flows in animal disease models and investigating hemodynamic characteristics and circulatory vascular diseases.

  3. Ocular Blood Flow Measurements in Healthy White Subjects Using Laser Speckle Flowgraphy.

    Directory of Open Access Journals (Sweden)

    Nikolaus Luft

    Full Text Available To assess the feasibility and reliability of Laser Speckle Flowgraphy (LSFG to measure ocular perfusion in a sample of healthy white subjects and to elucidate the age-dependence of the parameters obtained.This cross-sectional study included 80 eyes of 80 healthy, non-smoking white subjects of Western European descent between 19 and 79 years of age. A commercial LSFG instrument was applied to measure ocular blood flow at the optic nerve head (ONH three successive times before and after pharmacological pupil dilation. The mean blur rate (MBR, a measure of relative blood flow velocity, was obtained for different regions of the ONH. Eight parameters of ocular perfusion derived from the pulse-waveform analysis of MBR including blowout time (BOT and falling rate (FR were also recorded.Artifact-free LSFG images meeting the quality criteria for automated image analysis were obtainable in 93.8% without pupil dilation and in 98.8% with pharmacological pupil dilation. Measurements of MBR showed excellent repeatability with intraclass correlation coefficients ≥ 0.937 and were barely affected by pupil dilation. The majority of pulse-waveform derived variables exhibited equally high repeatability. MBR-related blood flow indices exhibited significant age dependence (p<0.001. FR (r = 0.747, p<0.001 and BOT (r = -0.714, p<0.001 most strongly correlated with age.LSFG represents a reliable method for the quantitative assessment of ocular blood flow in white subjects. Our data affirms that the LSFG-derived variables FR and BOT may be useful biomarkers for age-related changes in ocular perfusion.

  4. Cerebral Blood Flow Measurement Using fMRI and PET: A Cross-Validation Study

    Directory of Open Access Journals (Sweden)

    Jean J. Chen

    2008-01-01

    Full Text Available An important aspect of functional magnetic resonance imaging (fMRI is the study of brain hemodynamics, and MR arterial spin labeling (ASL perfusion imaging has gained wide acceptance as a robust and noninvasive technique. However, the cerebral blood flow (CBF measurements obtained with ASL fMRI have not been fully validated, particularly during global CBF modulations. We present a comparison of cerebral blood flow changes (ΔCBF measured using a flow-sensitive alternating inversion recovery (FAIR ASL perfusion method to those obtained using H2O15 PET, which is the current gold standard for in vivo imaging of CBF. To study regional and global CBF changes, a group of 10 healthy volunteers were imaged under identical experimental conditions during presentation of 5 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared using 3 types of region-of-interest (ROI masks. FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average ΔCBF of 21.5±8.2% for FAIR versus 28.2±12.8% for PET at maximum stimulation intensity. Nonetheless, there was a strong correlation between measurements of the two modalities. Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL ΔCBF for all 3 ROI types indicated no significant difference from unity (P>.05.

  5. Evaluation of MR angiography and blood flow measurement in abdominal and peripheral arterial occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Tabuchi, Kenji [Dokkyo Univ. School of Medicine, Mibu, Tochigi (Japan)

    2000-03-01

    To assess the characteristics of blood flow measurement with MR Angiography (MRA) to evaluate the status of vascular stenoses, two or three dimensional time-of-flight MRA and velocity-encoded cine MR were performed in the 230 segments of 35 patients, with abdominal and peripheral arterial occlusive diseases. In 11 of these 35 patients digital subtraction angiography was additionally underwent, and the stenotic findings was compared with MRA. There were 17 segments in which the velocity could not be measured, because the blood flow exceeded the upper limit of peak-encoded velocity (VENC) which was set at 120 cm/sec. Therefore, it is necessary to set the upper limit of VENC at higher than 120 cm/sec. There were 11 stenotic findings in DSA and 20 stenotic findings in MRA. Pulsatility Index (PI=(max velocity-min. velocity)/average velocity) were used for evaluating the blood flow waveform, and there were significant difference between the 11 stenotic findings of DSA and the others'. In summery, MRA was considered as useful examination to assess the degree of the vascular stenoses in abdominal and peripheral arterial occlusive disease. (author)

  6. [Effect of decreased ocular perfusion pressure on iris blood flow measured by laser Doppler flowmetry].

    Science.gov (United States)

    Chamot, S R; Movaffaghy, A; Petrig, B L; Riva, C E

    1999-05-01

    To determine whether iris blood flow (IBF) is regulated in response to an acute decrease in mean ocular perfusion pressure (PPm = MOAP-IOP, MOAP = mean ophthalmic arterial pressure) induced by increasing the intraocular pressure (IOP). Iris blood flow was measured using a slit lamp incorporating a laser Doppler flowmetry (LDF) module. The study was conducted on 12 normal volunteers (14 to 59 years old). IOP was raised using a scleral suction cup. In Exp. #1, the suction pressure was successively raised in steps of 50 to 100 mm Hg, each lasting about 10 sec, until IOP reached the MOAP level. In Exp. #2, the suction was raised to 200 mm Hg in 4 successive steps of 2 min duration. In Exp. #1, no significant change of IBF was observed for small decreases of PPm ( 23%).

  7. Glucose Pump Test can be Used to Measure Blood Flow Rate of ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Blood flow rates of AV fistula can be affected by osmotic and oncotic pressures of blood and arterial blood pressures. Sodium, glucose, hemoglobin, and albumin are significant effectors, created osmotic and oncotic pressures [Table 3]. Blood levels of hemoglobin. (Hb), albumin, sodium (Na), and glucose ...

  8. 133-xenon intravenous injection method for regional cerebral blood flow measurements

    International Nuclear Information System (INIS)

    Shinohara, Yukito; Takagi, Shigeharu; Kobatake, Keitaro

    1984-01-01

    The non-invasive 133-Xenon intravenous (IV) injection method for measuring regional cerebral blood flow (rCBF) has many advantages compared to the 133-Xenon inhalation method. In order to evaluate the possibility of clinical application of this IV injection method, normal regional and mean hemispheric values of rCBF were determined in this study. The rCBF data were obtained on 27 normal Japanese right-handed volunteers with an age range of 18 to 81 years (mean age 43). The subjects were requested to relax, keeping the eyes closed but without falling asleep. End-tidal 133-Xenon curves were used for correction of recirculation. The blood flow of the fast compartment (gray matter) of the brain was calculated, as well as the initial slope index (ISI) and the relative weight and the fractional flow of the fast compartment. CBF values thus obtained were compared to those obtained by the 133-Xenon inhalation method previously reported by us. The mean gray matter flow values for the right hemisphere was 90.3 +- 17.5 ml/100 g brain/min (mean +- S.D.) and that for the left was 90.0 +- 17.8. The mean value of ISI for the right hemisphere was 75.1 +- 17.0 and that for the left was 74.6 +- 17.0. There was no significant difference of blood flow between the hemispheres. These values were higher than those obtained by the inhalation method. The reason for this difference is discussed. The rCBF values were the highest frontally and the lowest parietooccipitally in both hemispheres, which is in good agreement with the results obtained by the other non-invasive methods and the intracarotid injection method. It is concluded that the 133-Xenon intravenous injection method, which has many advantages compared with the inhalation method, is applicable for rCBF measurements in man. (author)

  9. Regional blood flow during exercise in humans measured by near-infrared spectroscopy and indocyanine green

    DEFF Research Database (Denmark)

    Boushel, R; Langberg, Henning; Olesen, J

    2000-01-01

    Using near-infrared spectroscopy (NIRS) and the tracer indocyanine green (ICG), we quantified blood flow in calf muscle and around the Achilles tendon during plantar flexion (1-9 W). For comparison, blood flow in calf muscle was determined by dye dilution in combination with magnetic resonance...... NIRS and ICG to quantify regional tissue blood flow during exercise in humans. Due to its high spatial and temporal resolution, the technique may be useful for determining regional blood flow distribution and regulation during exercise in humans....

  10. The continuous high-precision measurement of the density of flowing blood.

    Science.gov (United States)

    Kenner, T; Leopold, H; Hinghofer-Szalkay, H

    1977-07-29

    The "mechanical oscillator" technique for the measurement of the density of fluids is based on the influence of mass on the natural frequency of a mechanical oscillator. The practical application of this principle was worked out by Kratky et al. (1969) and Leopold (1970). It is demonstrated in this study that the method permits the continuous high-precision measurement of the density of flowing blood in anesthetized animals. The accuracy is 10(5) g/ml, the maximum sampling rate 20/min. As found in rabbits and cats during the control state, physiological blood density changes related to spontaneous blood pressure variations are up to 2-10(4) g/ml. The method can be combined with i.v. injections of isotonic and iso-oncotic solutions to determine cardiac output and blood volume on the basis of a "density dilution" principle. Since the density of the interstitial fluid is lower than that of blood, fluid shifts through the capillary walls can be detected. The effects of hypertonic glucose and of hyperoncotic dextran have been examined. Changes in the density of the arterial blood appear within 10 s after i.v. injection of these fluids. Similarly, density changes result from hemorrhage and reinfusion. During and after i.v. administration of vasoactive drugs (noradrenaline, angiotensin II, acetylcholine), marked transient changes in blood density are seen which obviously reflect the effects of fluid shifts through the capillary walls. During hemorrhagic hypotension we found periodic variations in the blood density synchronous with spontaneously occurring Mayer waves. The new method seems to be a promising tool for investigations physiological and pathological capillary fluid dynamics.

  11. Renal blood flow and metabolism after cold ischaemia: peroperative measurements in patients with calculi

    DEFF Research Database (Denmark)

    Petersen, H K; Henriksen, Jens Henrik Sahl

    1984-01-01

    .01) immediately after re-established perfusion and 36% (P less than 0.02) 30 min later. In one additional patient, who had a short warm ischaemia (8 min), the flow pattern was the same. As arterial pressure remained constant, the reduced RBF signifies an increased renal vascular resistance. Renal O2-uptake......Peroperative measurements of renal blood flow (RBF), renal O2-uptake, and renal venous lactate/pyruvate (L/P) ratio were performed before and after a period of 30-71 min of hypothermic (10-15 degrees C) renal ischaemia in nine patients, undergoing surgery for renal calculi. Before ischaemia, RBF...... and renal venous L/P ratio were almost constant, indicating no significant anaerobic processes being involved in the flow response. None of the patients showed any signs of reactive hyperaemia. It is concluded that hypothermic renal ischaemia may be followed by an increased renal vascular resistance even...

  12. Blood flow characteristics of diabetic patients with complications detected by optical measurement.

    Science.gov (United States)

    An, Yuri; Kang, Yujung; Lee, Jungsul; Ahn, Chulwoo; Kwon, Kihwan; Choi, Chulhee

    2018-02-21

    Diabetes mellitus (DM) is one of the most common diseases worldwide. Uncontrolled and prolonged hyperglycemia can cause diabetic complications, which reduce the quality of life of patients. Diabetic complications are common in DM patients. Because it is impossible to completely recover from diabetic complications, it is important for early detection. In this study, we suggest a novel method of determining blood flow characteristics based on fluorescence image analysis with indocyanine green and report that diabetic complications have unique blood flow characteristics. We analyzed time-series fluorescence images obtained from controls, DM patients, and DM patients with complications. The images were segmented into the digits and the dorsum of the feet and hands, and each part has been considered as arterial and capillary flow. We compared the blood flow parameters in each region among the three groups. The DM patients with complications showed similar blood flow parameters to the controls, except the area under the curve and the maximum intensity, which indicate the blood flow volume. These parameters were significantly decreased in DM patients with complications. Although some blood flow parameters in the feet of DM patients with complications were close to normal blood flow, the vascular response of the macrovessels and microvessels to stimulation of the hands was significantly reduced, which indicates less reactivity in DM patients with complications. Our results suggest that DM patients, and DM patients with complications, have unique peripheral blood flow characteristics.

  13. Directly measuring spinal cord blood flow and spinal cord perfusion pressure via the collateral network: correlations with changes in systemic blood pressure.

    Science.gov (United States)

    Kise, Yuya; Kuniyoshi, Yukio; Inafuku, Hitoshi; Nagano, Takaaki; Hirayasu, Tsuneo; Yamashiro, Satoshi

    2015-01-01

    During thoracoabdominal surgery in which segmental arteries are sacrificed over a large area, blood supply routes from collateral networks have received attention as a means of avoiding spinal cord injury. The aim of this study was to investigate spinal cord blood supply through a collateral network by directly measuring spinal cord blood flow and spinal cord perfusion pressure experimentally. In beagle dogs (n = 8), the thoracoabdominal aorta and segmental arteries L1-L7 were exposed, and a temporary bypass was created for distal perfusion. Next, a laser blood flow meter was placed on the spinal dura mater in the L5 region to measure the spinal cord blood flow. The following were measured simultaneously when the direct blood supply from segmental arteries L2-L7 to the spinal cord was stopped: mean systemic blood pressure, spinal cord perfusion pressure (blood pressure within the aortic clamp site), and spinal cord blood flow supplied via the collateral network. These variables were then investigated for evidence of correlations. Positive correlations were observed between mean systemic blood pressure and spinal cord blood flow during interruption of segmental artery flow both with (r = 0.844, P flow with and without distal perfusion (r = 0.803, P network from outside the interrupted segmental arteries, and high systemic blood pressure (∼1.33-fold higher) was needed to obtain the preclamping spinal cord blood flow, whereas 1.68-fold higher systemic blood pressure was needed when distal perfusion was halted. Spinal cord blood flow is positively correlated with mean systemic blood pressure and spinal cord perfusion pressure under spinal cord ischemia caused by clamping a wide range of segmental arteries. In open and endovascular thoracic and thoracoabdominal surgery, elevating mean systemic blood pressure is a simple and effective means of increasing spinal cord blood flow, and measuring spinal cord perfusion pressure seems to be useful for monitoring

  14. Reproduction of pressure field in ultrasonic-measurement-integrated simulation of blood flow.

    Science.gov (United States)

    Funamoto, Kenichi; Hayase, Toshiyuki

    2013-07-01

    Ultrasonic-measurement-integrated (UMI) simulation of blood flow is used to analyze the velocity and pressure fields by applying feedback signals of artificial body forces based on differences of Doppler velocities between ultrasonic measurement and numerical simulation. Previous studies have revealed that UMI simulation accurately reproduces the velocity field of a target blood flow, but that the reproducibility of the pressure field is not necessarily satisfactory. In the present study, the reproduction of the pressure field by UMI simulation was investigated. The effect of feedback on the pressure field was first examined by theoretical analysis, and a pressure compensation method was devised. When the divergence of the feedback force vector was not zero, it influenced the pressure field in the UMI simulation while improving the computational accuracy of the velocity field. Hence, the correct pressure was estimated by adding pressure compensation to remove the deteriorating effect of the feedback. A numerical experiment was conducted dealing with the reproduction of a synthetic three-dimensional steady flow in a thoracic aneurysm to validate results of the theoretical analysis and the proposed pressure compensation method. The ability of the UMI simulation to reproduce the pressure field deteriorated with a large feedback gain. However, by properly compensating the effects of the feedback signals on the pressure, the error in the pressure field was reduced, exhibiting improvement of the computational accuracy. It is thus concluded that the UMI simulation with pressure compensation allows for the reproduction of both velocity and pressure fields of blood flow. Copyright © 2012 John Wiley & Sons, Ltd.

  15. Evaluation of a new high power, wide separation laser Doppler probe : Potential measurement of deeper tissue blood flow

    NARCIS (Netherlands)

    Clough, Geraldine; Chipperfield, Andrew; Byrne, Christopher; de Mul, Frits; Gush, Rodney

    Objective: To compare the output from a novel high power, wide separation laser Doppler flow probe (DP1-V2-HP, 4 mm, with IRLD20) with that of a standard flow probe (DP1-V2, 0.5 mm, with DRT4) (Moor UK) and to explore its potential for use in the noninvasive measurement of blood flow in deeper

  16. Magnetic particle imaging for in vivo blood flow velocity measurements in mice

    Science.gov (United States)

    Kaul, Michael G.; Salamon, Johannes; Knopp, Tobias; Ittrich, Harald; Adam, Gerhard; Weller, Horst; Jung, Caroline

    2018-03-01

    Magnetic particle imaging (MPI) is a new imaging technology. It is a potential candidate to be used for angiographic purposes, to study perfusion and cell migration. The aim of this work was to measure velocities of the flowing blood in the inferior vena cava of mice, using MPI, and to evaluate it in comparison with magnetic resonance imaging (MRI). A phantom mimicking the flow within the inferior vena cava with velocities of up to 21 cm s‑1 was used for the evaluation of the applied analysis techniques. Time–density and distance–density analyses for bolus tracking were performed to calculate flow velocities. These findings were compared with the calibrated velocities set by a flow pump, and it can be concluded that velocities of up to 21 cm s‑1 can be measured by MPI. A time–density analysis using an arrival time estimation algorithm showed the best agreement with the preset velocities. In vivo measurements were performed in healthy FVB mice (n  =  10). MRI experiments were performed using phase contrast (PC) for velocity mapping. For MPI measurements, a standardized injection of a superparamagnetic iron oxide tracer was applied. In vivo MPI data were evaluated by a time–density analysis and compared to PC MRI. A Bland–Altman analysis revealed good agreement between the in vivo velocities acquired by MRI of 4.0  ±  1.5 cm s‑1 and those measured by MPI of 4.8  ±  1.1 cm s‑1. Magnetic particle imaging is a new tool with which to measure and quantify flow velocities. It is fast, radiation-free, and produces 3D images. It therefore offers the potential for vascular imaging.

  17. The measurement of blood flow in the cerebral hemispheres using a radioactive tracer

    International Nuclear Information System (INIS)

    Calegaro, J.U.M.; Reis, J.M.M. dos; Lopes, P.G.; Ribeiro, J.I.C.; Mansano, A.

    1978-01-01

    The modified Olendorf technique to measure the passage of a non-diffusible radioactive tracer through the cerebral hemispheres is described. The results given as brain transit time presents the following normal values: right hemisphere = 11,0 +- 2,8s (s.d.); left hemisphere = 11,0 +- 2,9s (s.d.). The equipment used is a two scintillation detectors sistem (with flat field collimation) with simultaneous chard recorder. The values obtained are taken as cerebral blood flow index. From 20 patients studied, 12 have obstructive carotid [pt

  18. Development of a Compact-Sized Falling Needle Rheometer for Measurement of Flow Properties of Fresh Human Blood

    Science.gov (United States)

    Yamamoto, Hideki; Kawamura, Kimito; Omura, Kazunobu; Tokudome, Shogo

    2010-12-01

    A compact-sized falling needle rheometer with rapid operation and automatic flow analysis has been developed for viscometry of fresh human blood without anticoagulant. The volume of a fresh blood sample only needs to be 3 mL, and the measuring time is within 2 min after taking a blood sample from the human body. Measured flow properties of human blood are evaluated as a flow curve, that is, the relationship between the shear stress ( τ) and shear rate ( γ). Observed flow curves of fresh human blood show three typical fluid regions, that is, the Casson fluid region for a low shear rate range of 0 140 s-1, the transition region for a shear rate near 140 s-1 400 s-1. Flow properties of human blood such as the yield stress ( τ y) in the Casson fluid region and the apparent viscosity ( μ) in the Newtonian fluid region are measured, and they are compared between male and female blood. It is found that the range of human blood viscosity for males is (5.5 to 6.4) mPa · s, and for females is (4.5 to 5.3) mPa · s. The viscosities of male blood without anticoagulant show higher values than those of female blood. Human blood viscosities with anticoagulant show a lower value than that without anticoagulant. A linear relationship between the hematocrit value, that is, the volume percentage of red corpuscles in the human blood, and the apparent viscosity are observed for both male and female blood. This article is concerned with the flow analysis of fresh human blood viscosity without anticoagulant using a newly developed compact-sized falling needle rheometer.

  19. An improved design of optical sensor for long-term measurement of arterial blood flow waveform.

    Science.gov (United States)

    Djurić, Biljana; Suzić, Slavica; Stojadinović, Bojana; Nestorović, Zorica; Ivanović, Marija; Suzić-Lazić, Jelena; Nešić, Dejan; Mazić, Sanja; Tenne, Tamar; Zikich, Dragoslav; Žikić, Dejan

    2017-09-01

    We present here the improved design and development of optical sensor for non-invasive measurements of arterial blood flow waveform. The sensor is based on a physical principle of reflective photoplethysmography (PPG). As the light source we used serially connected infrared diodes whereas NPN silicon phototransistors were used as light detectors. The electronic components were molded into square package and poured with silicone. Such preparation produced an elastic superficies that allowed excellent attachment of the sensor on the skin's surface. Moreover, a serial connection of infrared diodes and phototransistors completely eliminated signal artifacts caused by minor muscle contractions. The sensor recording performances were examined at the photoplethysmographic sites on three different arteries; the commune carotid, femoral and radial and, on each site the sensor demonstrated remarkable capability to make a consistent, reproducible measurements. Because of the advantageous physical and electrical properties, the new sensor is suitable for various cardiovascular diagnostics procedures, especially when long-term measurements of arterial blood flow waveform are required, for monitoring of different parameters in cardiovascular units and for research.

  20. Synchronized Measurements of Maximum Blood Flow Velocities in Carotid, Brachial and Femoral Arteries, and ECG in Human Posture Changes

    National Research Council Canada - National Science Library

    Hirao, Y

    2001-01-01

    ...., sitting to standing and standing to sitting) using an ultrasonic Doppler technique. The ultrasonic Doppler technique can measure the dynamics of blood flow in arteries that exist deep within the human body...

  1. Relationship Between Uterine and Ovarian Arterial Blood Flow Measured by Doppler Sonography at Different Stages of Puberty

    Directory of Open Access Journals (Sweden)

    Reza Golestani

    2008-03-01

    Conclusion: Uterine and ovarian arterial blood flow, measured by Doppler sonography, was not useful for the evaluation of pubertal stages. However, it should be investigated with a greater sample size.

  2. Blood flow and blood volume in the femoral heads of healthy adults according to age. Measurement with positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Kubo, Toshikazu; Kimori, Kokuto; Nakamura, Fuminori; Inoue, Shigehiro; Fujioka, Mikihiro; Ueshima, Keiichiro; Hirasawa, Yasusuke; Ushijima, Yo; Nishimura, Tsunehiko

    2001-01-01

    To deepen understanding of hemodynamics in the femoral head, i.e., the essential factor in clarifying pathogenesis of hip disorders, this study examined blood flow and blood volume in the femoral heads of healthy adults, and their changes with age, by using positron emission tomography (PET). In 16 healthy adult males (age: 20-78 years old, mean age: 42 years), blood flow was measured by means of the H 2 15 O dynamic study method, and blood volume was measured by means of the 15 O-labeled carbon monoxide bolus inhalation method. Blood flow was 1.68-6.47 ml/min/100 g (mean ±SD: 3.52±1.2), and blood volume was 1.67-6.03 ml/100 g (mean ±SD: 3.00±1.27). Blood flow significantly decreased (p<0.01) with age, and blood volume significantly increased (P<0.05). PET was useful in the measurement of blood flow and blood volume in the femoral heads. With age, physiological hemodynamic changes also increased in femoral heads. (author)

  3. Gingival blood flow under total combs by functional pressure evaluated with laser-Doppler flowmetry, a non-invasive method of blood flow measurement

    International Nuclear Information System (INIS)

    Hengl, St.

    1996-09-01

    Gingival blood flow under total-combs by functional pressure evaluated with Laser-Doppler Flowmetry, a non-invasive method of blood flow measurement. Microcirculation of gum's capillary system can be measured non-invasive by Laser-Doppler-Flowmetry (LDF). Circulation, defined by the number of floating erythrocytes per unit of time, is measured by a fibro-optical Laser-Doppler-Flowmetry. The task was to examine, if there is any change of gum's circulation during strain and relief. Circulation on defined measurepoints, divided on the four quadrants, was determined among maximal strain and subsequent relief, on one probationer (complete denture bearer). Before every measure session systemic pressure was taken. LDF-value was taken on top of jaw-comb, in doing so, to get reproducible result and a satisfying fixation of the probe, there was made an artificial limb of the upper and lower comb. In the upper comb a dynamometer-box, which determined minimal and maximal comb pressure, was integrated. The received results of the LDF-measurement, expressed as perfusion units (PU) were lower under applied pressure than by pressure points more distant. Hyperemia, resulting during relief, seemed the more intense, the less perfusion was before. This new, non-invasive kind of circulation measurement seems to be quite predestined to be used for gingival diagnostic under artificial limb in the future. (author)

  4. Non invasive blood flow measurement in cerebellum detects minimal hepatic encephalopathy earlier than psychometric tests.

    Science.gov (United States)

    Felipo, Vicente; Urios, Amparo; Giménez-Garzó, Carla; Cauli, Omar; Andrés-Costa, Maria-Jesús; González, Olga; Serra, Miguel A; Sánchez-González, Javier; Aliaga, Roberto; Giner-Durán, Remedios; Belloch, Vicente; Montoliu, Carmina

    2014-09-07

    To assess whether non invasive blood flow measurement by arterial spin labeling in several brain regions detects minimal hepatic encephalopathy. Blood flow (BF) was analyzed by arterial spin labeling (ASL) in different brain areas of 14 controls, 24 cirrhotic patients without and 16 cirrhotic patients with minimal hepatic encephalopathy (MHE). Images were collected using a 3 Tesla MR scanner (Achieva 3T-TX, Philips, Netherlands). Pulsed ASL was performed. Patients showing MHE were detected using the battery Psychometric Hepatic Encephalopathy Score (PHES) consisting of five tests. Different cognitive and motor functions were also assessed: alterations in selective attention were evaluated using the Stroop test. Patients and controls also performed visuo-motor and bimanual coordination tests. Several biochemical parameters were measured: serum pro-inflammatory interleukins (IL-6 and IL-18), 3-nitrotyrosine, cGMP and nitrates+nitrites in plasma, and blood ammonia. Bivariate correlations were evaluated. In patients with MHE, BF was increased in cerebellar hemisphere (P = 0.03) and vermis (P = 0.012) and reduced in occipital lobe (P = 0.017). BF in cerebellar hemisphere was also increased in patients without MHE (P = 0.02). Bimanual coordination was impaired in patients without MHE (P = 0.05) and much more in patients with MHE (P battery and with CFF. BF in cerebellar hemisphere correlates with plasma cGMP and nitric oxide (NO) metabolites. BF in vermis cerebellar also correlates with NO metabolites and with 3-nitrotyrosine. IL-18 in plasma correlates with BF in thalamus and occipital lobe. Non invasive BF determination in cerebellum using ASL may detect MHE earlier than the PHES. Altered NO-cGMP pathway seems to be associated to altered BF in cerebellum.

  5. Cerebral distribution of 133Xe and blood flow measured with high purity germanium

    International Nuclear Information System (INIS)

    Reich, T.; Rusinek, H.; Youdin, M.; Clagnaz, M.

    1985-01-01

    Distribution of cerebral blood flow was measured with an array of 200 ultra-pure germanium radiation detectors and 133 Xe by inhalation. The array sees the head as a composite of different subvolumes and enables measurement of the concentration history of tracer every 1-10 sec in each subvolume simultaneously. Subvolume mean flows, (fm), and partition coefficients, lambda m, are derived by compartmental analysis of tissue concentration washout curves. Errors from cross talk, scalp radiation, look through, and assumed partition coefficients are eliminated. Average fm adjusted for 40 mm Hg PACO 2 in 14 cortical subvolumes (7 right, 7 left) of four normal 21-24 year old controls ranged from 50 to 60 ml/100 cc tissue/min, and lambda m ranged from 0.97 to 1.14. Average fm and lambda m in white matter was 24 ml/100 cc/min and 1.42 - 1.14 respectively. During CO 2 inhalation, right and left hemispheric fm increased 6.4% and 5.7%/mm Hg respectively, whereas white matter fm increased 2.2% and 3.4% mm Hg respectively. There was no systematic difference between front and back or dominant vs non-dominant sides. Three 73-84 year old controls had reduced fm and CO 2 reactivity in all subvolumes, lambda m was in the same range as in younger controls. Two patients with intracranial cerebrovascular disease showed excellent localization of ischemic subvolumes. One patient with asymptomatic unilateral 98% stenosis of the internal carotid artery had a similar distribution of blood flow in both hemispheres

  6. Stable xenon CT measurement of cerebral blood flow in cardiac transplantation candidates: Correlation with cognitive function

    International Nuclear Information System (INIS)

    Bello, J.A.; Fink, M.E.; Hilal, S.K.; Rose, E.A.; Reemtsma, K.

    1987-01-01

    Thirteen consecutive unselected patients with NYHA class 4 cardiac failure referred for cardiac transplantation underwent neurologic examination and cerebral blood flow measurement (rCBF) using the stable xenon enhanced CT method on a GE9800 system. Eleven men and two women were studied (mean age = 43.8 +- 6.1). On neurological examination, six of the patients demonstrated normal mental function; the remaining seven patients demonstrated memory, language, or learning impairment. There was no difference in mean cardiac output between the groups (4.9 L/min +- 1.68 vs. 4.2L/min +- 1.57). rCBF was significantly reduced in the impaired group. Cognitive impairment in patients with cardiac failure can be correlated with cerebral ischemia. Stable xenon CT measurement of rCBF in transplant candidates may help identify patients requiring more rapid transplantation to prevent permanent cerebral injury

  7. Determination of the amplitude and phase relationships between oscillations in skin temperature and photoplethysmography-measured blood flow in fingertips.

    Science.gov (United States)

    Sagaidachnyi, A A; Skripal, A V; Fomin, A V; Usanov, D A

    2014-02-01

    It is well established that skin temperature oscillations in fingertips coexist with blood flow oscillations and there is a certain correlation between them. At the same time, the reasons for differences in waveform and the delay between the blood flow and temperature oscillations are far from being fully understood. In this study we determine the relationships between spectral components of the blood flow and temperature oscillations in fingertips, and we ascertain the frequency dependences of amplitude attenuation and delay time for the temperature oscillations. The blood flow oscillations were considered as a source of thermal waves propagating from micro-vessels towards the skin surface and manifesting as temperature oscillations. The finger temperature was measured by infrared thermography and blood flow was assessed by photoplethysmography for ten healthy subjects. The time-frequency analysis of oscillations was based on the Morlet wavelet transform. The frequency dependences of delay time and amplitude attenuation in temperature compared with blood flow oscillations have been determined in endothelial (0.005-0.02 Hz) and neurogenic (0.02-0.05 Hz) frequency bands using the wavelet spectra. We approximated the experimental frequency dependences by equations describing thermal wave propagation through the medium and taking into account the thermal properties and thickness of a tissue. Results of analysis show that with the increase of frequency f the delay time of temperature oscillations decreases inversely proportional to f(1/2), and the attenuation of the amplitude increases directly proportional to exp f(1/2). Using these relationships allows us to increase correlation between the processed temperature oscillations and blood flow oscillations from 0.2 to 0.7 within the frequency interval 0.005-0.05 Hz. The established experimental and theoretical relationships clarify an understanding of interrelation between the dynamics of blood flow and skin

  8. Blood flow measurement of brain tumor by sup 123 I-IMP using 3-heads rotating gamma camera SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Makiko; Yui, Nobuharu; Togawa, Takashi; Namba, Hiroki; Kinoshita, Fujimi; Koakutsu, Masaki (Chiba Cancer Center (Japan)); Minoshima, Satoshi; Uchida, Yoshitaka; Arimizu, Noboru

    1991-12-01

    Using 3-heads rotating gamma camera SPECT system, regional blood flow was measured from the super-early image obtained 4 to 6 minutes after the intravenous injection of {sup 123}I-IMP on 11 patients with various brain tumors. Two cases of olfactory groove meningioma and malignant astrocytoma showed significantly high {sup 123}I-IMP uptake by the lesion visualized by MRI compared to the uptake by normal brain cortex on super-early image but {sup 123}I-IMP uptake by the tumor decreased on early image. In both cases, blood flow of the tumor measured from super-early image showed values much higher than those of normal brain cortex. It was thought that usual correction method based on early image did not correctly represent the blood flow of the lesion but that the present method based on super-early image could show the increase of blood flow of the tumor. (author).

  9. Radionuclide assessment of peripheral hemodynamics: a new technique for measurement of forearm blood volume and flow

    Energy Technology Data Exchange (ETDEWEB)

    Todo, Y.; Tanimoto, M.; Yamamoto, T.; Iwasaki, T.

    1986-02-01

    A new peripheral hemodynamic measurement system using /sup 99m/Tc-labeled red blood cells has been developed. This method was carried out on 22 normal subjects, 29 with coronary artery disease, and two with dilated cardiomyopathy. Peripheral hemodynamic indices obtained from this method included forearm blood volume (FBV), venous capacity (FVC), venous capacity index (VCI), blood flow (FBF), and vascular resistance (FVR), and were compared with the central hemodynamic parameters of left ventricular filling pressure (LVFP), cardiac output (CO), and total systemic vascular resistance (TSVR) obtained with an invasive technique. The normal values were FBV 8.54 +/- 2.04 ml/100 ml; FVC 4.54 +/- 1.23 ml/100 ml; VCI 65.5 +/- 3.8%; FBF 4.26 +/- 0.56 ml/100 ml/min; and FVR 20.9 +/- 4.4 mmHg/ml/100 ml/min. These values were in good agreement with the values reported using conventional plethysmography. The 16 patients with congestive heart failure (NYHA Class II or III) showed significantly lower FBV, FVC, and FBF values and significantly higher VCI and FVR values than the healthy subjects. Capacitance vessel parameters (FBV, FVC, and VCI) and LVFP, FBF and CO, and FVR and TSVR each showed significant correlation; reproducibility was also good. The advantages of this method are (a) the detector does not come in contact with the region being measured; (b) it is possible to ascertain the absolute quantity of blood in the tissue; (c) extravasation of the plasma component can be ignored; and (d) data processing is simple.

  10. Female rat pancreatic blood flow measured by 133Xe clearance technique: pregnancy influence and oestradiol immediate effect

    International Nuclear Information System (INIS)

    Faure, Annette; Vuillemin, J.-P.; Ducassou, Dominique; Bouchard, Alain; Valeyre, Jacques; Sutter-Dub, M.-T.

    1981-01-01

    Female Rat pancreatic blood flow is measured by 133 Xe clearance technique without interruption blood circulation. Its value is enhanced during late pregnancy, but not immediately influenced by exogenous glucose and/or oestradiol. Relation with glucose-induced insulin hypersecretion is discussed [fr

  11. Time-resolved blood flow measurement in the in vivo mouse model by optical frequency domain imaging

    Science.gov (United States)

    Walther, Julia; Mueller, Gregor; Meissner, Sven; Cimalla, Peter; Homann, Hanno; Morawietz, Henning; Koch, Edmund

    2009-07-01

    In this study, we demonstrate that phase-resolved Doppler optical frequency domain imaging (OFDI) is very suitable to quantify the pulsatile blood flow within a vasodynamic measurement in the in vivo mouse model. For this, an OFDI-system with a read-out rate of 20 kHz and a center wavelength of 1320 nm has been used to image the time-resolved murine blood flow in 300 μμm vessels. Because OFDI is less sensitive to fringe washout due to axial sample motion, it is applied to analyze the blood flow velocities and the vascular dynamics in six-week-old C57BL/6 mice compared to one of the LDLR knockout strain kept under sedentary conditions or with access to voluntary wheel running. We have shown that the systolic as well as the diastolic phase of the pulsatile arterial blood flow can be well identified at each vasodynamic state. Furthermore, the changes of the flow velocities after vasoconstriction and -dilation were presented and interpreted in the entire physiological context. With this, the combined measurement of time-resolved blood flow and vessel diameter provides the basis to analyze the vascular function and its influence on the blood flow of small arteries of different mouse strains in response to different life styles.

  12. Early changes in blood flow of the mouse skin after irradiation as measured by the 133Xe clearance method

    International Nuclear Information System (INIS)

    Tsujii, Hirohiko; Irie, Goro

    1983-01-01

    The early effects of radiation on the local blood flow in the skin of mice were evaluated by measuring the local clearance rate of 133 Xe after its subcutaneous injection; this was done at four to five weeks after irradiation during the animals' normal resting conditions. The fractionation schedules employed were single fractions, two fractions in 15 days and four fractions in 15 days. The dose effect curves with these schedules showed a two-component pattern. There was a uniform reduction in flood flow after 10 to 30 Gy, and a steady increase in flood flow after doses more than 40 Gy. The blood flow after higher-fractionated doses was always lower than less-fractionated doses. It was considered that radiation doses causing higher severity of acute skin reactions might have predominated a degree of acute vasodilatation over fibrotic changes, thus resulting in increased blood flow. A steady increase in early blood flow was observed with increasing severity of acute skin reactions, but the early blood flow was not a good indicator for predicting late skin reactions, except for a severe leg deformity which was accompanied with a significant increase in early blood flow. (author)

  13. A new sensor for stress measurement based on blood flow fluctuations

    Science.gov (United States)

    Fine, I.; Kaminsky, A. V.; Shenkman, L.

    2016-03-01

    It is widely recognized that effective stress management could have a dramatic impact on health care and preventive medicine. In order to meet this need, efficient and seamless sensing and analytic tools for the non-invasive stress monitoring during daily life are required. The existing sensors still do not meet the needs in terms of specificity and robustness. We utilized a miniaturized dynamic light scattering sensor (mDLS) which is specially adjusted to measure skin blood flow fluctuations and provides multi- parametric capabilities. Based on the measured dynamic light scattering signal from the red blood cells flowing in skin, a new concept of hemodynamic indexes (HI) and oscillatory hemodynamic indexes (OHI) have been developed. This approach was utilized for stress level assessment for a few usecase scenario. The new stress index was generated through the HI and OHI parameters. In order to validate this new non-invasive stress index, a group of 19 healthy volunteers was studied by measuring the mDLS sensor located on the wrist. Mental stress was induced by using the cognitive dissonance test of Stroop. We found that OHIs indexes have high sensitivity to the mental stress response for most of the tested subjects. In addition, we examined the capability of using this new stress index for the individual monitoring of the diurnal stress level. We found that the new stress index exhibits similar trends as reported for to the well-known diurnal behavior of cortisol levels. Finally, we demonstrated that this new marker provides good sensitivity and specificity to the stress response to sound and musical emotional arousal.

  14. A microfluidic device for simultaneous measurement of viscosity and flow rate of blood in a complex fluidic network.

    Science.gov (United States)

    Jun Kang, Yang; Yeom, Eunseop; Lee, Sang-Joon

    2013-01-01

    Blood viscosity has been considered as one of important biophysical parameters for effectively monitoring variations in physiological and pathological conditions of circulatory disorders. Standard previous methods make it difficult to evaluate variations of blood viscosity under cardiopulmonary bypass procedures or hemodialysis. In this study, we proposed a unique microfluidic device for simultaneously measuring viscosity and flow rate of whole blood circulating in a complex fluidic network including a rat, a reservoir, a pinch valve, and a peristaltic pump. To demonstrate the proposed method, a twin-shaped microfluidic device, which is composed of two half-circular chambers, two side channels with multiple indicating channels, and one bridge channel, was carefully designed. Based on the microfluidic device, three sequential flow controls were applied to identify viscosity and flow rate of blood, with label-free and sensorless detection. The half-circular chamber was employed to achieve mechanical membrane compliance for flow stabilization in the microfluidic device. To quantify the effect of flow stabilization on flow fluctuations, a formula of pulsation index (PI) was analytically derived using a discrete fluidic circuit model. Using the PI formula, the time constant contributed by the half-circular chamber is estimated to be 8 s. Furthermore, flow fluctuations resulting from the peristaltic pumps are completely removed, especially under periodic flow conditions within short periods (T flow rate conditions [(a) known blood flow rate via a syringe pump, (b) unknown blood flow rate via a peristaltic pump]. As a result, the flow rate and viscosity of blood can be simultaneously measured with satisfactory accuracy. In addition, the proposed method was successfully applied to identify the viscosity of rat blood, which circulates in a complex fluidic network. These observations confirm that the proposed method can be used for simultaneous measurement of viscosity

  15. Dynamic contrast enhanced CT measurement of blood flow during interstitial laser photocoagulation: comparison with an Arrhenius damage model

    International Nuclear Information System (INIS)

    Purdie, T.J.; Lee, T.J.; Iizuka, M.; Sherar, M.D.

    2000-01-01

    One effect of heating during interstitial laser photocoagulation (ILP) is to directly destroy the tumour vasculature resulting in a loss of viable blood supply. Therefore, blood flow measured during and after treatment can be a useful indicator of tissue thermal damage. In this study, the effect of ILP treatment on rabbit thigh tumours was investigated by measuring blood flow changes using dynamic contrast enhanced computed tomography (CT). The CT measured changes in blood flow of treated tumour tissue were fitted to an Arrhenius model assuming first order rate kinetics. Our results show that changes in blood flow of tumour tissue distant from surrounding normal tissue are well described by an Arrhenius model. By contrast, the temperature profile of tumour tissue adjacent to normal tissue must be modified to account for heat dissipation by the latter. Finally, the Arrhenius parameters derived in the study are similar to those derived by heating tumour tissue to a lower temperature (<47 deg. C) than the current study. In conclusion, CT can be used to monitor blood flow changes during ILP and these measurements are related to the thermal damage predicted by the Arrhenius model. (author)

  16. Measurement of lower limb blood flow in patients with neurogenic claudication using positron emission tomography.

    Science.gov (United States)

    Keenan, G F; Ashcroft, G P; Roditi, G H; Hutchison, J D; Evans, N T; Mikecz, P; Chaloner, F; Dodd, M; Leonard, C; Porter, R W

    1995-02-15

    Ten subjects (seven with neurogenic claudication and three control subjects) underwent examination of lower limb muscle blood flow before and after exercise using positron emission tomography. To investigate the hypothesis that lower limb muscle ischemia was the origin of symptoms in neurogenic claudication. Patients with neurogenic claudication secondary to spinal stenosis experience lower limb discomfort after exercise similar to that of ischemic claudication. However, they do not have clinical evidence of peripheral vascular disease. The authors postulated that the lower limb discomfort in patients with neurogenic claudication may arise from muscle ischemia due to inadequate dilatation of arterioles in response to exercise, this itself arising secondary to sympathetic dysfunction due to spinal stenosis. Using O15-labeled water and positron emission tomography measured thigh and leg muscle blood flow response to exercise bilaterally in seven patients with unilateral neurogenic claudication and three control subjects were measured. The average values obtained for mid-thigh and mid-calf muscle perfusion at rest were 2.57 ml/min/100 g tissue (2.23-3.90) and 2.39 ml/min/100 g tissue (2.03-3.46), respectively. The average values obtained from mid-thigh and mid-calf perfusion after exercise were 4.41 ml/min/100 g tissue (2.8-6.0) and 4.87 ml/min/100 g (2.2-11.7). We found no difference in muscle perfusion between symptomatic and asymptomatic limbs in this group of patients. These studies suggest that muscle ischemia is not the origin of symptoms in most patients with neurogenic claudication.

  17. Synchrotron X-ray PIV Technique for Measurement of Blood Flow Velocity

    International Nuclear Information System (INIS)

    Kim, Guk Bae; Lee, Sang Joon; Je, Jung Ho

    2007-01-01

    Synchrotron X-ray micro-imaging method has been used to observe internal structures of various organisms, industrial devices, and so on. However, it is not suitable to see internal flows inside a structure because tracers typically employed in conventional optical flow visualization methods cannot be detectable with the X-ray micro-imaging method. On the other hand, a PIV (particle image velocimetry) method which has recently been accepted as a reliable quantitative flow visualization technique can extract lots of flow information by applying digital image processing techniques However, it is not applicable to opaque fluids such as blood. In this study, we combined the PIV method and the synchrotron X-ray micro-imaging technique to compose a new X-ray PIV technique. Using the X-ray PIV technique, we investigated the optical characteristics of blood for a coherent synchrotron X-ray beam and quantitatively visualized real blood flows inside an opaque tube without any contrast media. The velocity field information acquired would be helpful for investigating hemorheologic characteristics of the blood flow

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-15

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

  20. Animal models for the evaluation of radiopharmaceuticals to measure brian blood flow and function

    International Nuclear Information System (INIS)

    Welch, M.J.; Marshall, L.G.I.; Mathias, C.J.

    1987-01-01

    Several techniques have been utilized to carry out initial evaluation of radiopharmaceuticals labeled with technetium-99m and other radionuclides. The simplest technique is to measure the amount of radioactivity in the brain in rats or mice following the intravenous administration of these compounds; brain uptake and washout of radiopharmaceuticals can be estimated. More sophisticated techniques involve measuring the uptake and egress of the radiopharmaceutical following carotid artery administration in rats of primates. The Oldendorf technique compares a tracer with a standard compound e.g. tritiated water, to measure the brain uptake index of various compounds determined by decapiation at short times following administration. Another technique in which consecutive administrations of the compound to be studied and oxygen-15-labeled water are injected via the carotid artery of primates; the brain extraction and washout of the unknown tracer can be evaluated. The blood flow can be varied by altering the pCO 2 of the animal. Examples will be given and techniques compared

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

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  2. Evaluation of a new high power, wide separation laser Doppler probe: potential measurement of deeper tissue blood flow.

    Science.gov (United States)

    Clough, Geraldine; Chipperfield, Andrew; Byrne, Christopher; de Mul, Frits; Gush, Rodney

    2009-09-01

    To compare the output from a novel high power, wide separation laser Doppler flow probe (DP1-V2-HP, 4 mm, with IRLD20) with that of a standard flow probe (DP1-V2, 0.5 mm, with DRT4) (Moor UK) and to explore its potential for use in the noninvasive measurement of blood flow in deeper tissues in humans. Monte Carlo modeling was used to predict depths of light scattering in skin with each probe, geometry. Experimentally, forearm blood flow was measured at rest and during local warming of the skin surface and post occlusion reactive hyperaemia (PORH). Laser Doppler blood flux (LDF) and the power spectral density of its component frequency intervals, were compared. Monte Carlo modeling indicated that while the majority of wide probe LD signal derives from deeper tissue, a significant portion is from superficial (dermal) tissue (and vice versa for standard probe). Perturbation of local blood flow differentially increased LDF and spectral power as measured by the two probes, with the standard skin probe showing a significantly greater response to local skin warming (p<0.01). These differences support our hypothesis that the wide probe is recording predominantly blood flux within the vasculature of sub-dermal tissue. This is in agreement with Monte Carlo simulation.

  3. Monitoring variables affecting positron emission tomography measurements of cerebral blood flow in anaesthetized pigs

    DEFF Research Database (Denmark)

    Alstrup, Aage Kristian Olsen; Zois, Nora Elisabeth; Simonsen, Mette

    2018-01-01

    Background Positron emission tomography (PET) imaging of anaesthetized pig brains is a useful tool in neuroscience. Stable cerebral blood flow (CBF) is essential for PET, since variations can affect the distribution of several radiotracers. However, the effect of physiological factors regulating...

  4. Monitoring variables affecting positron emission tomography measurements of cerebral blood flow in anaesthetized pigs

    DEFF Research Database (Denmark)

    Alstrup, Aage Kristian Olsen; Zois, Nora Elisabeth; Simonsen, Mette

    Background: Positron emission tomography (PET) imaging of anaesthetised pig brains is a useful tool in neuroscience. Stable cerebral blood flow (CBF) is essential for PET, since variations can affect the kinetics of several radiotracers. However, the impact of physiological factors regulating CBF...

  5. Cerebral blood flow and oxygen metabolism of peritumorous edema measured with PET

    International Nuclear Information System (INIS)

    Tomura, N.; Kato, T.; Kanno, I.; Shishido, F.; Murakami, M.; Vemura, K.; Ogawa, T.; Mineura, K.

    1989-01-01

    The purpose of this paper is to study the cerebral blood flow and metabolism of peritumorous edema to evaluate its basic mechanism and reversibility. The cerebral blood flow (CBF), oxygen metabolism (CMRO 2 ), and cerebral blood volume (CBV) of peritumorous edema in seven cases of glioma were studied and compared with those of acute ischemic brain edema in nine cases. In peritumorous edema, the CBF (27.3 mL/100 mL/min ± 5.4) and the CMRO 2 (2.17 mL/100mL/min ± 0.62) both remained above 1.5 mL/100 mL/min, that is, above the reversible threshold in ischemic brain tissue. It has been shown that the peritumorous edema was of the vasogenic type and might be reversible tissue if tumor was removed

  6. ''Blood flow measurements in the irradiated pig skin using β emitters radionuclides''

    International Nuclear Information System (INIS)

    Daburon, F.; Lefaix, J.L.; Leplat, J.J.; Fayart, G.; Delacroix, D.; Le Thanh, P.

    1997-01-01

    Non invasive methods of study of the skin blood flow are numerous, but generally do not give any indication on the cutaneous micro-circulatory flow, except for cutaneous laser Doppler. The isotopic exploration of the skin with injected γ radionuclides, even of weak energy, doe snot allow to characterize the skin blood flow, because of the important contribution of the subcutaneous tissues. The use of β emitters energy spectrum, analyzed by different quantitative methods, are proportional to the thickness of the screen localized between the radioactive source and detector. Using simple and complex phantoms composed of tissue equivalent screens, with 32 P sources placed at different depths, it was possible to study the degradation of β spectra, simulating respectively the sub-epidermis and sub-dermis vascular levels. A modelization and an experimental study in-vivo are proposed in this work, with 32 P phosphate administered intravenously in pigs. (author)

  7. Hyperhomocysteinemia decreases bone blood flow

    Directory of Open Access Journals (Sweden)

    Neetu T

    2011-01-01

    Full Text Available Neetu Tyagi*, Thomas P Vacek*, John T Fleming, Jonathan C Vacek, Suresh C TyagiDepartment of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY, USA *These authors have equal authorshipAbstract: Elevated plasma levels of homocysteine (Hcy, known as hyperhomocysteinemia (HHcy, are associated with osteoporosis. A decrease in bone blood flow is a potential cause of compromised bone mechanical properties. Therefore, we hypothesized that HHcy decreases bone blood flow and biomechanical properties. To test this hypothesis, male Sprague–Dawley rats were treated with Hcy (0.67 g/L in drinking water for 8 weeks. Age-matched rats served as controls. At the end of the treatment period, the rats were anesthetized. Blood samples were collected from experimental or control rats. Biochemical turnover markers (body weight, Hcy, vitamin B12, and folate were measured. Systolic blood pressure was measured from the right carotid artery. Tibia blood flow was measured by laser Doppler flow probe. The results indicated that Hcy levels were significantly higher in the Hcy-treated group than in control rats, whereas vitamin B12 levels were lower in the Hcy-treated group compared with control rats. There was no significant difference in folate concentration and blood pressure in Hcy-treated versus control rats. The tibial blood flow index of the control group was significantly higher (0.78 ± 0.09 flow unit compared with the Hcy-treated group (0.51 ± 0.09. The tibial mass was 1.1 ± 0.1 g in the control group and 0.9 ± 0.1 in the Hcy-treated group. The tibia bone density was unchanged in Hcy-treated rats. These results suggest that Hcy causes a reduction in bone blood flow, which contributes to compromised bone biomechanical properties.Keywords: homocysteine, tibia, bone density

  8. Advances in regional cerebral blood flow measurement and patho-physiological analysis by SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Odano, Ikuo (Niigata Univ. (Japan). School of Medicine)

    1994-04-01

    Recently, two kinds of radiopharmaceuticals have been developed to represent the biodistribution of regional blood flow, which are N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) and [sup 99m]Tc-hexamethylpropylene-amine-oxime (HMPAO). The charachteristics, clinical usage and imitation of these two radiolabeled agents are discussed. The advantage of [sup 123]I-IMP is that it has high first-pass extraction and long retention in brain tissue, hence it can be used to measure the absolute values of regional cerebral blood flow (rCBF). When the kinetics of [sup 123]I-IMP is assumed to be freely diffusible in the brain, its behavior is considered by 2-compartment model, especially which is assumed by the microsphere model in the early period after the i.v. injection of [sup 123]I-IMP. Comparing the rCBF measured by [sup 123]I-IMP with that by [sup 133]Xe inhalation SPECT method, we have to consider PaCO[sub 2] when both SPECT studies are performed, because PaCO[sub 2] is one of the big factors which make effects on the alteration of rCBF. [sup 123]I-IMP has an interesting character of the redistribution phenomenon which represrent the degree of ischemia in the cerebrovascular diseases. Distribution volume an important datum obtained by the SPECT study with [sup 123]I-IMP, which represent the degree of retention, i.e. binding potential of [sup 123]I-IMP in the brain tissue. I introduced the usage of the distribution volume of [sup 123]I-IMP, which was constructed in the rate constant square method, in the differential diagnosis of Parkinson's disease and progressive supranuclear palsy (PSP). The clinical usage of [sup 99m] Tc-HMPAT was mentioned, the advantage of which is the rapid fixation in the brain tissue and the distribution does not change for long time after the i.v. injection. Hence [sup 99m]Tc-HMPAO is used for the diagnosis of epileptic foci and certain loading tests such as balloon occlusion test, postural test and acetazolamide loading test. (author).

  9. Perfusion MRI (dynamic susceptibility contrast imaging) with different measurement approaches for the evaluation of blood flow and blood volume in human gliomas

    DEFF Research Database (Denmark)

    Thomsen, H; Steffensen, E; Larsson, Elna-Marie

    2012-01-01

    technique arterial spin labelling (ASL) presently provides measurement only of cerebral blood flow (CBF), which has not been widely used in human brain tumor studies. Purpose: To assess if measurement of blood flow is comparable with measurement of blood volume in human biopsy-proven gliomas obtained by DSC......, and glioblastomas. Results: rCBF and rCBV measurements obtained with the maximum perfusion method were correlated when normalized to white matter (r ¼ 0.60) and to the cerebellum (r ¼ 0.49). Histogram analyses of rCBF and rCBV showed that mean and median values as well as skewness and peak position were correlated......-MRI using two different regions for normalization and two different measurement approaches. Material and Methods: Retrospective study of 61 patients with different types of gliomas examined with DSC perfusion MRI. Regions of interest (ROIs) were placed in tumor portions with maximum perfusion on rCBF and r...

  10. Electromagnetic flowmetry--an experimental method for continuous blood flow measurement using a new island flap model.

    Science.gov (United States)

    Banis, J C; Schwartz, K S; Acland, R D

    1980-10-01

    We describe a reliable experimental method for direct, continuous measurement of the rate of blood flow in an island skin flap, using an electromagnetic flowmeter applied to the artery of the flap. The canine saphenous island flap model, developed as part of this study, is a large (11 x 14 cm) island flap, based solely on the saphenous artery (2 mm in diameter). We describe the anatomy of the flap and the method of raising it. Electromagnetic flowmetry is the only method of blood flow determination that provides immediate, continuous, and quantitative measurement of flow. We describe the principles and pitfalls of the electromagnetic flowmeter and the numerous rules of practice that must be observed to obtain consistent results. A validation study was carried out, in which we simultaneously measured arterial inflow with the flowmeter and venous outflow from the flap using direct collection. This study was based on the assumption that at any point in time the arterial and venous rate of flow were equal. We present the results of the study, which show an extremely close linear relationship between the measured and actual rates of flow. We intend to use this experimental method to study the factors that affect the rate of blood flow in free skin flap transfer.

  11. Noninvasive quantitative measurement of cerebral blood flow with [sup 123]I-IMP; Lung monitoring method

    Energy Technology Data Exchange (ETDEWEB)

    Oguchi, Kazuhiro; Kasuga, Toshio; Sone, Shusuke; Nakanishi, Fumiko; Ito, Atsuko (Shinshu Univ., Matsumoto, Nagano (Japan). Faculty of Medicine); Tanizaki, Yoshio

    1993-06-01

    In order to perform a less invasive determination of regional cerebral blood flow (rCBF) using N-isopropyl-p-[[sup 123]I] iodoamphetamine (I-123-IMP), we used the lung clearance curve as a substitute for the arterial blood activity curve as an input function. We assumed that a major portion of the intravenously injected I-123-IMP initially accumulates in the lung and then is gradually cleared from the lung pool to enter the systemic circulation. In this case lung clearance could be considered nearly equal to the integral of arterial blood activity shown during the examination. We used a single probe detector to obtain the lung clearance curve as the difference between sequential lung activity and peak lung activity. The absolute value of the sequential change in arterial blood activity was estimated from the differentiated lung clearance curve compared with the arterial blood activity that was estimated by actual blood sampling once during the examination. The rCBF was calculated by the thus estimated arterial blood activity curve and brain activity by SPECT image using the microsphere model. The values of rCBF obtained by this method were similar to those obtained by the continuous arterial sampling method, and this lung monitoring method was thought to be applicable to clinical use. (author).

  12. Microscopic Measurements of Axial Accumulation of Red Blood Cells in Capillary Flows Effects of Deformability

    Science.gov (United States)

    Sasaki, Takahiro; Seki, Junji; Itano, Tomoaki; Sugihara-Seki, Masako

    2017-11-01

    In the microcirculation, red blood cells (RBCs) are known to accumulate in the region near the central axis of microvessels, which is called the ``axial accumulation''. Although this behavior of RBCs is considered to originate from high deformability of RBCs, there have been few experimental studies on the mechanism. In order to elucidate the effect of RBC deformability on the axial accumulation, we measured the cross-sectional distributions of RBCs flowing through capillary tubes with a high spatial resolution by a newly devised observation system for intact and softened RBCs as well as hardened RBCs to various degrees. It was found that the intact and softened RBCs are concentrated in the small area centered on the tube axis, whereas the hardened RBCs are dispersed widely over the tube cross section dependent on the degree of hardness. These results demonstrate clearly the essential role of the deformability of RBCs in the ``axial accumulation'' of RBCs. JSPS KAKENHI Grant Number 17H03176, Kansai University ORDIST group funds.

  13. The evaluation of the automatic setting of ROI to SPECT measuring cerebral blood flow

    International Nuclear Information System (INIS)

    Mizuno, Hiroshi; Takahashi, Masaaki; Yoshioka, Katsunori

    2007-01-01

    It has been pointed out that the manual settings of region of interest (ROI) to the single-photon-emission-computed-tomography (SPECT) slice lacked objectivity when the fixed quantity value of regional cerebral blood flow (rCBF) was measured previously. Therefore, we jointly developed software Brain ROI'' with Daiichi Radioisotope Laboratories, Ltd. (DRL) that normalized an individual brain to a standard brain template by using Statistical Parametric Mapping 2 (SPM 2) of easy Z-score Imaging System ver. 3.0 (eZIS Ver. 3.0), and, ROI template was set to a specific slice. In this paper, we evaluated the accuracy of this software with ROI template that we made the useful size of the shape, in some clinical samples. As a result, the method of the automatic setting of ROI was the objectively. However, we thought that we should use the shape of ROI template without an influence of Brain atrophy. Moreover, we should see Normalizing individual brain and confirm the accuracy of normalization. When failing in normalization, we should partially correct ROI or set all by the manual operation of the operator. However, it was thought that this software was useful if the tendency was understood because the failure example was few. (author)

  14. Regional cerebral blood flow during the auditory oddball task measured by positron emission tomography

    International Nuclear Information System (INIS)

    Mochida, Masahiko

    1997-01-01

    Regional cerebral blood flow (rCBF) was measured by employing PET in nine healthy right-handed male subjects, while they simultaneously performed the auditory oddball task using tone bursts. Results showed that the rCBF value was highest in the transverse gyrus of Heschl in both right and left hemispheres. When comparing the rCBF values between right and left hemispheres, four areas had higher rCBF values in the left hemisphere and eight areas had higher rCBF values in the right hemisphere. Of these, the anterior and posterior parts of the superior temporal gyrus, especially, showed significant differences. The hemispheric differences in the rCBF values of the auditory areas can be attributed to the performance of the oddball task which requires higher processing of non verbal auditory input. The P300 amplitude which reflects the amount of the allocated information processing resources correlated positively with rCBF in the following areas: left piriform cortex, the transverse gyrus of Heschl in both left and right hemispheres. Mean-while, P300 amplitude correlated negatively with rCBF in the nucleus accumbens septi in both right and left hemispheres. The N100 amplitude evoked by frequent stimulus did not correlate with rCBF in almost all ROIs. (K.H.)

  15. Determination of the amplitude and phase relationships between oscillations in skin temperature and photoplethysmography-measured blood flow in fingertips

    International Nuclear Information System (INIS)

    Sagaidachnyi, A A; Skripal, A V; Fomin, A V; Usanov, D A

    2014-01-01

    It is well established that skin temperature oscillations in fingertips coexist with blood flow oscillations and there is a certain correlation between them. At the same time, the reasons for differences in waveform and the delay between the blood flow and temperature oscillations are far from being fully understood. In this study we determine the relationships between spectral components of the blood flow and temperature oscillations in fingertips, and we ascertain the frequency dependences of amplitude attenuation and delay time for the temperature oscillations. The blood flow oscillations were considered as a source of thermal waves propagating from micro-vessels towards the skin surface and manifesting as temperature oscillations. The finger temperature was measured by infrared thermography and blood flow was assessed by photoplethysmography for ten healthy subjects. The time–frequency analysis of oscillations was based on the Morlet wavelet transform. The frequency dependences of delay time and amplitude attenuation in temperature compared with blood flow oscillations have been determined in endothelial (0.005–0.02 Hz) and neurogenic (0.02–0.05 Hz) frequency bands using the wavelet spectra. We approximated the experimental frequency dependences by equations describing thermal wave propagation through the medium and taking into account the thermal properties and thickness of a tissue. Results of analysis show that with the increase of frequency f the delay time of temperature oscillations decreases inversely proportional to f 1/2 , and the attenuation of the amplitude increases directly proportional to exp f 1/2 . Using these relationships allows us to increase correlation between the processed temperature oscillations and blood flow oscillations from 0.2 to 0.7 within the frequency interval 0.005–0.05 Hz. The established experimental and theoretical relationships clarify an understanding of interrelation between the dynamics of blood flow and skin

  16. Multivariate evaluation of brain function by measuring regional cerebral blood flow and event-related potentials

    International Nuclear Information System (INIS)

    Koga, Yoshihiko; Mochida, Masahiko; Shutara, Yoshikazu; Nakagawa, Kazumi; Nagata, Ken

    1998-01-01

    To measure the effect of events on human cognitive function, effects of odors by measurement regional cerebral blood flow (rCBF) and P300 were evaluated during the auditory odd-ball exercise. PET showed the increase in rCBF on the right hemisphere of the brain by coffee aroma. rCBF was measured by PET in 9 of right-handed healthy adults men, and P300 was by event-related potential (ERP) in each sex of 20 right-handed healthy adults. ERP showed the difference of the P300 amplitude between men and women, and showed the tendency, by odors except the lavender oil, that women had higher in the P300 amplitude than men. These results suggest the presence of effects on the cognitive function through emotional actions. Next, the relationship between rCBF and ERP were evaluated. The subjects were 9 of the right-handed healthy adults (average: 25.6±3.4 years old). rCBF by PET and P300 amplitude by ERP were simultaneously recorded during the auditory odd-ball exercise using the tone-burst method (2 kHz of the low frequency aimed stimuli and 1 kHz of the high frequency non-aimed stimuli). The rCBF value was the highest at the transverse gyrus of Heschl and the lowest at the piriform cortex among 24 regions of interest (ROI) from both sides. The difference of P300 peak latent time among ROI was almost the same. The brain waves from Cz and Pz were similar and the average amplitude was highest at Pz. We found the high correlation in the right piriform cortex (Fz), and right (Fz, Cz) and left (Cz, Pz) transverse gyrus of Heschl between the P300 amplitude and rCBF. (K.H.)

  17. Dual-Wavelength Laser Speckle Contrast Imaging (dwLSCI Improves Chronic Measurement of Superficial Blood Flow in Hands

    Directory of Open Access Journals (Sweden)

    Lingke Zhang

    2017-12-01

    Full Text Available Laser speckle contrast imaging (LSCI has been widely used to determine blood flow and perfusion in biological tissues. The physical model of traditional LSCI ignores the effects of scattering property distribution in relation to speckle correlation time τc and blood flow v, which further results in biased estimation. In this study, we developed a dual-wavelength laser speckle contrast imaging (dwLSCI method and a portable device for imaging the blood flow and tissue perfusion in human hands. Experimental data showed that dwLSCI could retrieve the vein vasculatures under the surface skin, and it further provided accurate measurements of vein blood flow signals, tissue perfusion signals, and fingertip perfusion signals, which assist with assessments of rehabilitation therapy for stroke patients. Fingertip perfusion signals demonstrated better performance in early assessments, while vein blood flow signals assisted the Fugl–Meyer Assessment Scale (FMA and the Wolf Motor Function Test (WMFT behavior assessments. As a general noninvasive imaging method, dwLSCI can be applied in clinical studies related to hand functions combined with behavior assessments.

  18. Dual-Wavelength Laser Speckle Contrast Imaging (dwLSCI) Improves Chronic Measurement of Superficial Blood Flow in Hands

    Science.gov (United States)

    Zhang, Lingke; Ding, Li; Li, Miao; Zhang, Xiaoli; Su, Diansan; Jia, Jie; Miao, Peng

    2017-01-01

    Laser speckle contrast imaging (LSCI) has been widely used to determine blood flow and perfusion in biological tissues. The physical model of traditional LSCI ignores the effects of scattering property distribution in relation to speckle correlation time τc and blood flow v, which further results in biased estimation. In this study, we developed a dual-wavelength laser speckle contrast imaging (dwLSCI) method and a portable device for imaging the blood flow and tissue perfusion in human hands. Experimental data showed that dwLSCI could retrieve the vein vasculatures under the surface skin, and it further provided accurate measurements of vein blood flow signals, tissue perfusion signals, and fingertip perfusion signals, which assist with assessments of rehabilitation therapy for stroke patients. Fingertip perfusion signals demonstrated better performance in early assessments, while vein blood flow signals assisted the Fugl–Meyer Assessment Scale (FMA) and the Wolf Motor Function Test (WMFT) behavior assessments. As a general noninvasive imaging method, dwLSCI can be applied in clinical studies related to hand functions combined with behavior assessments. PMID:29206145

  19. Protocol for measuring myocardial blood flow by PET/CT in cats

    Energy Technology Data Exchange (ETDEWEB)

    Jenni, Simone D.; Glaus, Tony M. [University of Zurich, Division of Cardiology, Clinic for Small Animal Internal Medicine, Vetsuisse Faculty, Zurich (Switzerland); Schepis, Tiziano; Siegrist, Patrick T. [University Hospital Zurich, Cardiovascular Center, Nuclear Cardiology, Zurich (Switzerland); Jenni, Rolf [University Hospital, Cardiovascular Center, Echocardiography, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiovascular Center, Nuclear Cardiology, Zurich (Switzerland)]|[University of Zurich, Zurich Center for Integrative Human Physiology, Zurich (Switzerland)

    2009-02-15

    The aim of this study was to establish a protocol for measuring myocardial blood flow (MBF) by PET/CT in healthy cats. The rationale was its future use in Maine Coon cats with hypertrophic cardiomyopathy (HCM) as a model for human HCM. MBF was measured in nine anaesthetized healthy cats using a PET/CT scanner and {sup 13}NH{sub 3} at rest and during adenosine infusion. Each cat was randomly assigned to receive vasodilator stress with two or three adenosine infusions at the following rates ({mu}g/kg per minute): 140 (Ado 1, standard rate for humans), 280 (Ado 2, twice the human standard rate), 560 (Ado 4), 840 (Ado 6) and 1,120 (Ado 8). The median MBF at rest was 1.26 ml/min per g (n = 9; range 0.88-1.72 ml/min per g). There was no significant difference at Ado 1 (n = 3; median 1.35, range 0.93-1.55 ml/min per g; ns) but MBF was significantly greater at Ado 2 (n = 6; 2.16, range 1.35-2.68 ml/min per g; p < 0.05) and Ado 4 (n = 6; 2.11, 1.92-2.45 ml/min per g; p < 0.05). Large ranges of MBF values at Ado 6 (n = 4; 2.53, 2.32-5.63 ml/min per g; ns) and Ado 8 (n = 3; 2.21, 1.92-5.70 ml/min per g; ns) were noted. Observed adverse effects, including hypotension, AV-block and ventricular premature contractions, were all mild, of short duration and immediately reversed after cessation of the adenosine infusion. MBF can be safely measured in cats using PET. An intravenous adenosine infusion at a rate of 280 {mu}g/kg per minute seems most appropriate to induce maximal hyperaemic MBF response in healthy cats. Higher adenosine rates appear less suitable as they are associated with a large heterogeneity in flow increase and rate pressure product, most probably due to the large variability in haemodynamic and heart rate response. (orig.)

  20. Improved evaluation of the coronary collateral circulation measuring the regional blood flow with 133Xe

    International Nuclear Information System (INIS)

    Franz, N.; Strangfeld, D.; Romaniuk, P.; Heublein, B.

    1988-01-01

    In 40 patients with angina pectoris catheter diagnostic measurements of the myocardial flow were carried out after intracoronary application of 133 Xe at rest and after oral application of Curantyl in order to obtain a better evaluation of coronary collaterals. The results show relations between angiographically detected coronary collaterals and the reduced coronary reserve. A quantitative measurement of collaterals from the angiogram facilitates a more precise evaluation of the relation between coronary sclerosis and myocardial flow. (author)

  1. Dependence of renal blood flow on renal artery stenosis measured using CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Luedemann, Lutz [Charite - Universitaetsmedizin Berlin (Germany). Dept. of Radiotherapy; Nafz, B.; Persson, P. [Charite - Universitaetsmedizin Berlin (Germany). Inst. for Vegetative Physiology; Elsner, F. [Krankenhaus am Urban, Berlin (Germany). Dept. of Anesthesiology; Grosse-Siestrup, C.; Meissler, M. [Charite - Universitaetsmedizin Berlin (Germany). Experimental Animal Unit; Gutberlet, M. [Charite - Universitaetsmedizin Berlin (Germany). Dept. of Diagnostic and Interventional Radiology; Univ. Leipzig/ Leipzig Heart Center (Germany). Dept. of Diagnostic and Interventional Radiology; Lengsfeld, P.; Voth, M. [Bayer-Schering Pharma AG, Berlin (Germany). Global Medical Affairs Diagnostic Imaging

    2011-03-15

    The present study investigates the suitability of computed tomography angiography (CTA) depicting the degree of renal artery stenosis for estimating renal blood flow (RBF) in a kidney. Materials and Methods: We investigated renal artery stenosis assessment by CTA in eight adult female hybrid pigs with an ultrasound probe implanted at the renal vein for RBF measurement. An inflatable metal-free cuff was placed around the renal artery to control the RBF. The RBF was then reduced in four steps. For each reduced RBF value and baseline RBF, CTA with a reconstructed slice thickness of 0.625 mm was performed in the arterial phase following injection of 80 ml of nonionic intravenous contrast medium. The radius of the stenotic and non-stenotic renal artery segment was measured in the reconstructed images. Results: A significant linear correlation (p < 0.0001) was found between the relative apparent stenosis (calculated as the ratio of the radii of the actual stenotic segment and a non-stenotic renal artery segment) and RBF. The linear regression yielded a slope of 0.57 and a y-axis of 24.1 %. A significant linear correlation (p < 0.0001) was also found between the relative true stenosis (the ratio of the radii of the actual stenotic segment and a non-stenotic renal artery segment at baseline) and the RBF. The linear regression yielded a slope of 0.67 and a y-axis of 13.8 %. Conclusion: The results show that the relative stenosis apparent on CTA differs from the true degree of renal artery stenosis. Nevertheless, the degree of renal artery stenosis determined by CTA provides a reliable estimate of the resulting RBF reduction. (orig.)

  2. Global cerebral blood flow changes measured by brain perfusion SPECT immediately after whole brain irradiation

    International Nuclear Information System (INIS)

    Ohtawa, Nobuyuki; Machida, Kikuo; Honda, Norinari; Hosono, Makoto; Takahashi, Takeo

    2003-01-01

    Whole brain irradiation (WBI) is still a major treatment option for patients with metastatic brain tumor despite recent advances in chemotherapy and newer techniques of radiation therapy. Cerebral blood flow (CBF) of changes induced by whole brain radiation is not fully investigated, and the aim of the study was to measure CBF changes non-invasively with brain perfusion SPECT to correlate with treatment effect or prognosis. Total of 106 patients underwent WBI during April 1998 to March 2002. Both brain MRI and brain perfusion SPECT could be performed before (less than 1 week before or less than 10 Gy of WBI) and immediately after (between 1 week before and 2 weeks after the completion of WBI) the therapy in 17 of these patients. They, 10 men and 7 women, all had metastatic brain tumor with age range of 45 to 87 (mean of 61.4) years. Tc-99m brain perfusion agent (HMPAO in 4, ECD in 13) was rapidly administered in a 740-MBq dose to measure global and regional CBF according to Matsuda's method, which based on both Patlak plot and Lassens' linearity correction. Brain MRI was used to measure therapeutic response according to World Health Organization (WHO) classification as complete remission (CR), partial response (PR), no change (NC), and progressive disease (PD). Survival period was measured from the completion of WBI. Mean global CBF was 40.6 and 41.5 ml/100 g/min before and immediately after the WBI, respectively. Four patients increased (greater than 10%) their global mean CBF, 10 unchanged (less than 10% increase or decrease), and 3 decreased after the WBI. The WBI achieved CR in none, PR in 8, NC in 6, and PD in 3 on brain MRI. Change in global mean CBF (mean±SD) was significantly larger in PR (4.3±2.0 ml/100 g/min, p=0.002) and in NC (-0.1±4.5) than in PD (-3.9±6.4, P=0.002, P=0.016, respectively). Survival was not significantly (p>0.05) different among the patients with CR (20 weeks), NC (48 weeks), and PD (21 weeks). Change in global CBF and survival was

  3. An effective method for skin blood flow measurement using local heat combined with electrical stimulation.

    Science.gov (United States)

    Almalty, A-M R; Petrofsky, J S; Al-Naami, B; Al-Nabulsi, J

    2009-01-01

    Electrical stimulation (ES) is a modality used to increase skin blood flow (SBF) and to aid in wound healing. A greater SBF in non wounded skin is induced if ES is used in a warm environment compared to a thermoneutral environment, where ES is usually applied. Therefore, in this paper, a method to investigate the effect of local heating and ES on the SBF is developed. A total of 33 males (18-40 years) were divided into group G (n = 15) who received the ES during a global heating protocol and group L (n = 18) who received ES during a local heating protocol. In the global heating protocol, ES (30 Hz, 250 micros) was applied for 15 min on the subject's thigh in thermoneutral (25 +/- 0.5 degrees C) and warm (35 +/- 0.5 degrees C) environments. In the local heating protocol, ES was applied for 15 minutes at 25 degrees C, 35 degrees C and 40 degrees C local skin temperatures. A laser Doppler imager measured the SBF in both protocols pre, during, and post ES. The results of the experiment showed the significant differences in the SBFs were found at pre, during, and post ES in a thermoneutral environment or when the skin was locally cooled to 25 degrees C. The SBFs were significantly increased during and post ES after global heating or during local heating at 35 degrees C and 40 degrees C. There were no significant differences in SBFs between the warm environment and at 35 degrees C of local heating. However, the SBF response to ES was the highest at 40 degrees C of local heating. Thus, ES during local heating of the skin, as well as during global heating is an effective method to increase SBF.

  4. Measurement of mean cerebral blood flow using SPECT and dementia rating scales in the memory clinic

    International Nuclear Information System (INIS)

    Kawahata, Nobuya; Daitoh, Nobuyuki; Shirai, Fumie; Yoshikawa, Ayumi; Gotoh, Chiharu

    1997-01-01

    We investigated the association between mean cerebral blood flow (mCBF) values using single photon emission computed tomography (SPECT) and cognitive performance scores of three dementia rating scales (ADAS, MMSE, HDS-R). Mean CBF was measured by the 123 I-IMP-ARG method in a selected group of 51 out-patients aged 41 to 90 years and by the 99m Tc-ECD method in the other group of 57 out-patients aged 51 to 91 years. Simple regressions were calculated for each of the neuropsychological clusters and mCBF values. In 123 I-IMP-ARG-SPECT study, there was a significant correlation between the mCBF values and HDS-R scores (R=0.37, p=0.01). 99m Tc-ECD-SPECT study revealed statistically significant correlations between the mCBF values and ADAS scores (R=-0.48, p 123 I-IMP-ARG-SPECT study and 99m Tc-ECD-SPECT study showed the progressive declines of mCBF with advancing cognitive dysfunctions. Using the cut-off point study (23/24 scores in MMSE and 20/21 scores in HDS-R), we have found that the patients with cognitive dysfunctions had lower mCBF values than the patients with those in each group of aged 60-69 years, 70-79 years, and 80-89 years. However, the difference of mCBF values between the groups with cognitive dysfunctions and without those had decreased gradually with advancing age. The present study suggests that SPECT can provide important functional informations to assess the cognitive impairment in patients with the memory disturbance. (author)

  5. Endometrial blood flow measured by xenon 133 clearance in women with normal menstrual cycles and dysfunctional uterine bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, I.S.; McCarron, G.; Hutton, B.; Macey, D.

    1987-01-01

    Endometrial blood flow was measured through the menstrual cycle in nonpregnant women (28 studies of 17 women with normal menstrual cycles and 32 studies of 20 women with dysfunctional uterine bleeding) with use of a clearance technique in which 100 to 400 microCi of the gamma-emitting isotope, xenon 133 in saline solution was instilled into the uterine cavity. The mean (+/- SEM) endometrial blood flow in normal cycles was 27.7 +/- 2.6 ml/100 gm/min, with a significant elevation in the middle to late follicular phase, followed by a substantial fall and a secondary slow luteal phase rise that was maintained until the onset of menstruation. There was a significant correlation between plasma estradiol levels and endometrial blood flow in the follicular but not the luteal phase. Blood flow patterns in women with ovulatory dysfunctional bleeding were similar to normal, except for a significantly lower middle follicular rate. Women with anovulatory dysfunctional bleeding exhibited exceedingly variable flow rates.

  6. Endometrial blood flow measured by xenon 133 clearance in women with normal menstrual cycles and dysfunctional uterine bleeding

    International Nuclear Information System (INIS)

    Fraser, I.S.; McCarron, G.; Hutton, B.; Macey, D.

    1987-01-01

    Endometrial blood flow was measured through the menstrual cycle in nonpregnant women (28 studies of 17 women with normal menstrual cycles and 32 studies of 20 women with dysfunctional uterine bleeding) with use of a clearance technique in which 100 to 400 microCi of the gamma-emitting isotope, xenon 133 in saline solution was instilled into the uterine cavity. The mean (+/- SEM) endometrial blood flow in normal cycles was 27.7 +/- 2.6 ml/100 gm/min, with a significant elevation in the middle to late follicular phase, followed by a substantial fall and a secondary slow luteal phase rise that was maintained until the onset of menstruation. There was a significant correlation between plasma estradiol levels and endometrial blood flow in the follicular but not the luteal phase. Blood flow patterns in women with ovulatory dysfunctional bleeding were similar to normal, except for a significantly lower middle follicular rate. Women with anovulatory dysfunctional bleeding exhibited exceedingly variable flow rates

  7. Blood flow and microgravity

    Science.gov (United States)

    Bureau, Lionel; Coupier, Gwennou; Dubois, Frank; Duperray, Alain; Farutin, Alexander; Minetti, Christophe; Misbah, Chaouqi; Podgorski, Thomas; Tsvirkun, Daria; Vysokikh, Mikhail

    2017-01-01

    The absence of gravity during space flight can alter cardio-vascular functions partially due to reduced physical activity. This affects the overall hemodynamics, and in particular the level of shear stresses to which blood vessels are submitted. Long-term exposure to space environment is thus susceptible to induce vascular remodeling through a mechanotransduction cascade that couples vessel shape and function with the mechanical cues exerted by the circulating cells on the vessel walls. Central to such processes, the glycocalyx - i.e. the micron-thick layer of biomacromolecules that lines the lumen of blood vessels and is directly exposed to blood flow - is a major actor in the regulation of biochemical and mechanical interactions. We discuss in this article several experiments performed under microgravity, such as the determination of lift force and collective motion in blood flow, and some preliminary results obtained in artificial microfluidic circuits functionalized with endothelium that offer interesting perspectives for the study of the interactions between blood and endothelium in healthy condition as well as by mimicking the degradation of glycocalyx caused by long space missions. A direct comparison between experiments and simulations is discussed. xml:lang="fr"

  8. Comparison of time-resolved and continuous-wave near-infrared techniques for measuring cerebral blood flow in piglets

    Science.gov (United States)

    Diop, Mamadou; Tichauer, Kenneth M.; Elliott, Jonathan T.; Migueis, Mark; Lee, Ting-Yim; Lawrence, Keith St.

    2010-09-01

    A primary focus of neurointensive care is monitoring the injured brain to detect harmful events that can impair cerebral blood flow (CBF), resulting in further injury. Since current noninvasive methods used in the clinic can only assess blood flow indirectly, the goal of this research is to develop an optical technique for measuring absolute CBF. A time-resolved near-infrared (TR-NIR) apparatus is built and CBF is determined by a bolus-tracking method using indocyanine green as an intravascular flow tracer. As a first step in the validation of this technique, CBF is measured in newborn piglets to avoid signal contamination from extracerebral tissue. Measurements are acquired under three conditions: normocapnia, hypercapnia, and following carotid occlusion. For comparison, CBF is concurrently measured by a previously developed continuous-wave NIR method. A strong correlation between CBF measurements from the two techniques is revealed with a slope of 0.79+/-0.06, an intercept of -2.2+/-2.5 ml/100 g/min, and an R2 of 0.810+/-0.088. Results demonstrate that TR-NIR can measure CBF with reasonable accuracy and is sensitive to flow changes. The discrepancy between the two methods at higher CBF could be caused by differences in depth sensitivities between continuous-wave and time-resolved measurements.

  9. Measurement of cerebral blood flow by means of intravenous injection of 133Xe

    International Nuclear Information System (INIS)

    Hliscs, R.; Franke, W.G.

    1977-01-01

    In administering 133 Xe intravenous injection is an alternative to arterial puncture. After injection the patient breathes into a closed respiratory loop in order to concentrate the activity in the body. Simultaneously, a scintillation camera scans the activity in brain and expired air in fixed time intervals. After opening the respiratory loop the wash process is recorded. The histograms recorded on magnetic tape and core store are corrected with regard to recirculation applying a new procedure. Data for calculating blood flow in grey and white cerebral tissue are obtained from three-compartment analysis

  10. Monitoring variables affecting positron emission tomography measurements of cerebral blood flow in anaesthetized pigs

    DEFF Research Database (Denmark)

    Alstrup, Aage Kristian Olsen; Zois, Nora Elisabeth; Simonsen, Mette

    2018-01-01

    Background Positron emission tomography (PET) imaging of anaesthetized pig brains is a useful tool in neuroscience. Stable cerebral blood flow (CBF) is essential for PET, since variations can affect the distribution of several radiotracers. However, the effect of physiological factors regulating...... and the monitoring parameters. Results No significant statistical correlations were found between CBF and the nine monitoring variables. However, we found that arterial carbon dioxide tension (PaCO2) and body temperature were important predictors of CBF that should be observed and kept constant. In addition, we...

  11. Measurement of the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography: Validation against fractional flow reserve.

    Science.gov (United States)

    Zafar, Haroon; Sharif, Faisal; Leahy, Martin J

    2014-12-01

    The main objective of this study was to assess the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography (FD-OCT). A correlation between fractional flow reserve (FFR) and FD-OCT derived blood flow velocity is also included in this study. A total of 20 coronary stenoses in 15 patients were assessed consecutively by quantitative coronary angiography (QCA), FFR and FD-OCT. A percutaneous coronary intervention (PCI) optimization system was used in this study which combines wireless FFR measurement and FD-OCT imaging in one platform. Stenoses were labelled severe if FFR ≤ 0.8. Blood flow rate and velocity in each stenosis segment were derived from the volumetric analysis of the FD-OCT pull back images. The FFR value was ≤ 0.80 in 5 stenoses (25%). The mean blood flow rate in severe coronary stenosis ( n  = 5) was 2.54 ± 0.55 ml/s as compared to 4.81 ± 1.95 ml/s in stenosis with FFR > 0.8 ( n  = 15). A good and significant correlation between FFR and FD-OCT blood flow velocity in coronary artery stenosis ( r  = 0.74, p  < 0.001) was found. The assessment of stenosis severity using FD-OCT derived blood flow rate and velocity has the ability to overcome many limitations of QCA and intravascular ultrasound (IVUS).

  12. Regional cerebral blood flow (rCBF) measurement by 133Xe inhalation (Inhamatic 33rCBF measuring instrument)

    International Nuclear Information System (INIS)

    Kuroda, Kiyoshi; Onodera, Hideki; Endo, Hideo.

    1982-01-01

    The rCBF and its patterns obtained by 133 Xe inhalation on 20 healthy subjects were studied. In a group of subjects aged 25 years or less, the fast flow (F1) representing the mean cerebral blood flow (MCBF) was 97.1 +- 15.7 m1/100 g/min (abbreviated as m1) in the left hemisphere and 96.6 +- 16.8 m1 in the right; and the initial slope index (ISI), 65.8 +- 10.4 m1 for the left and 65.1 +- 10.7 m1 for the right. In a group of subjects aged 25 or more, F1 was 83.5 +- 10.1 m1 for the left and 84.8 +- 9.6 m1 for the right; and ISI, 55.7 +- 6.9 m1 for the left and 55.8 +- 6.7 m1 for the right. In both groups, F1 showed a hyperfrontal pattern in which F1 was higher than MCBF in the frontal region by about 10%, and ISI showed high values primarily in the sylvian fissure. With respect to the variation of F1 values from the 1st to 2nd measurements, MCBF was 7.6 +- 5.1% in the left hemisphere and 9.0 +- 4.7% in the right; and ISI, 14.6 +- 5.1% in the left and 14.4 +- 10.6% in the right. Thus, F1 values showed higher reproducibility. Depending on the difference in start fit time (SFT), both F1 and ISI values showed great changes, particularly so when SFT was close to the peak of the head curve. (Chiba, N.)

  13. Study of Estimation Method for Unsteady Inflow Velocity in Two-Dimensional Ultrasonic-Measurement-Integrated Blood Flow Simulation.

    Science.gov (United States)

    Kadowaki, Hiroko; Hayase, Toshiyuki; Funamoto, Kenichi; Taniguchi, Nobuyuki

    2016-02-01

    Information on hemodynamics is essential for elucidation of mechanisms and development of novel diagnostic methods for circulatory diseases. Two-dimensional ultrasonic-measurement-integrated (2D-UMI) simulation can correctly reproduce an intravascular blood flow field and hemodynamics by feeding back an ultrasonic measurement to the numerical blood flow simulation. In this method, it is critically important to give the correct cross-sectional average inflow velocity (inflow velocity) as the boundary condition. However, systematic study has not been done on the relative validity and effectiveness of existing inflow velocity estimation methods for various target flow fields. The aim of this study was to examine the existing methods systematically and to establish a method to accurately estimate inflow velocities for various vessel geometries and flow conditions in 2D-UMI simulations. A numerical experiment was performed for 2D-UMI simulation of blood flow models in a straight vessel with inflow velocity profiles symmetric and asymmetric to the vessel axis using existing evaluation functions based on Doppler velocity error for the inflow velocity estimation. As a result, it was clarified that a significantly large estimation error occurs in the asymmetric flow due to a nonfeedback domain near the downstream end of the calculation domain. Hence, a new inflow velocity estimation method of 2D-UMI simulation is proposed in which the feedback and evaluation domains are extended to the downstream end. Further numerical experiments of 2D-UMI simulation for two realistic vessel geometries of a healthy blood vessel and a stenosed one confirmed the effectiveness of the proposed method.

  14. Study on the tomographic cerebral blood flow measurement with stable xenon inhalation

    International Nuclear Information System (INIS)

    Kimura, Kazumoto; Ueda, Yasuichi; Nagai, Masakatsu; Segawa, Hiromu.

    1983-01-01

    This study was conducted to obtain quantitative values of regional cerebral blood flow (rCBF) by serial CT scanning during non radioactive xenon (Xe) inhalation. The present study provided not only rCBF map but build up rate (k) map and partition coefficient (lambda) map both in normal and pathological brain tissues. The lambda map can not be readily obtained by radioisotope (RI) or positron emission CT method. These maps provided high resolution enough to identify white matter, gray matter and even deep structure of the brain such as caudate nucles, thalums and internal capsule, and were directly compared with CT image. Resolution of each map permited visualization of small area as much as 1-3 mm in diameter. Blood flow for gray matter was 82+-11 and that for white matter was 24+-5 ml/100 g/min in seven normal subjects. The inhalation time of Xe gas and the scanning interval influenced the k, lambda, and rCBF map, respectively. In order to visualize the distribution of white matter on lambda map, it required more than 20 min inhalation of the gas. The scanning interval for good map was every 3 min in the first 9 min and every 5 min in the later period. (author)

  15. Clinical blood flow measurements with O-15 water and Positron Emission Tomography (PET)

    International Nuclear Information System (INIS)

    Hichwa, R.D.; Watkins, G.L.; Boles Ponto, L.L.

    1993-01-01

    Traditionally PET chemists have been primarily involved in development and synthesis of radiopharmaceuticals for imaging. If greater clinical utility and research productivity are to be achieved in the PET field, then this role must be expanded to include not just the synthesis of the end product, but also the efficient and timely delivery of the radiopharmaceutical. Hence, the chemist must also consider (1) more automation of synthesis and QC procedures, (2) reduced radiopharmaceutical preparation time with emphasis towards on-line syntheses whenever feasible, (3) integrated cyclotron/chemistry operations, (4) dose delivery schemes to minimize staff exposure while maintaining purity, sterility and apyrogenicity, and (5) technologist/technician operability of all procedures. At the University of Iowa, techniques have been employed to stream-line the production synthesis, delivery, and imaging of O-15 labelled water for determination of tissue blood flow. Automated cyclotron and PET tomograph operation, as well as steady-state production of O-15 water permit a single PET technologist to conduct qualitative blood flow studies on demand for routine or emergency procedures

  16. Flow measurements in a blood-perfused collagen vessel using x-ray micro-particle image velocimetry.

    Directory of Open Access Journals (Sweden)

    Elizabeth Antoine

    Full Text Available Blood-perfused tissue models are joining the emerging field of tumor engineering because they provide new avenues for modulation of the tumor microenvironment and preclinical evaluation of the therapeutic potential of new treatments. The characterization of fluid flow parameters in such in-vitro perfused tissue models is a critical step towards better understanding and manipulating the tumor microenvironment. However, traditional optical flow measurement methods are inapplicable because of the opacity of blood and the thickness of the tissue sample. In order to overcome the limitations of optical method we demonstrate the feasibility of using phase-contrast x-ray imaging to perform microscale particle image velocimetry (PIV measurements of flow in blood perfused hydrated tissue-representative microvessels. However, phase contrast x-ray images significantly depart from the traditional PIV image paradigm, as they have high intensity background, very low signal-to-noise ratio, and volume integration effects. Hence, in order to achieve accurate measurements special attention must be paid to the image processing and PIV cross-correlation methodologies. Therefore we develop and demonstrate a methodology that incorporates image preprocessing as well as advanced PIV cross-correlation methods to result in measured velocities within experimental uncertainty.

  17. Noninvasive xenon-133 measurements of cerebral blood flow using stationary detectors compared with dynamic emission tomography

    DEFF Research Database (Denmark)

    Schroeder, T; Vorstrup, S; Lassen, N A

    1986-01-01

    Repeated bedside measurements of CBF have been made possible by the recent development of a mobile unit with 10 stationary detectors using the intravenous xenon-133 method. To evaluate this technique, comparative CBF studies at rest and following the application of a cerebral vasodilatory stimulus...... (acetazolamide, 1 g i.v.) were performed with the mobile equipment and with xenon-133 single-photon emission inhalation tomography in patients with cerebrovascular disease. The CBF level and the flow response to acetazolamide as determined with the two methods were well correlated, although at low flow levels...

  18. Regional cerebral blood flow in Parkinson's disease measured with N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT

    International Nuclear Information System (INIS)

    Odano, Ikuo; Nishihara, Mamiko; Hayashi, Hiroko; Higuchi, Shoichi; Sakai, Kunio; Ishikawa, Atsushi; Ibayashi, Katsuhiko.

    1992-01-01

    N-isopropyl-p-[ 123 I]iodoamphetamine (IMP) SPECT studies were performed on 21 patients (13 females; 45-73 yrs) with idiopathic Parkinson's disease (PD) and 10 age-matched normal controls (39-69 yrs). Regional cerebral blood flow (rCBF) was quantitatively measured by the arterial blood sampling method. When compared with normal controls, global CBF, and rCBF in the frontal cortex and in the basal ganglia were reduced 22.1% (p 123 I-IMP SPECT imaging is useful for evaluation and follow-up of patients with PD. (author)

  19. Regulation of pulpal blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.

    1985-04-01

    The regulation of blood flow of the dental pulp was investigated in dogs and rats anesthetized with sodium pentobarbital. Pulpal blood flow was altered by variations of local and systemic hemodynamics. Macrocirculatory blood flow (ml/min/100 g) in the dental pulp was measured with both the /sup 133/Xe washout and the 15-microns radioisotope-labeled microsphere injection methods on the canine teeth of dogs, to provide a comparison of the two methods in the same tooth. Microcirculatory studies were conducted in the rat incisor tooth with microscopic determination of the vascular pattern, RBC velocity, and intravascular volumetric flow distribution. Pulpal resistance vessels have alpha- and beta-adrenergic receptors. Activation of alpha-receptors by intra-arterial injection of norepinephrine (NE) caused both a reduction in macrocirculatory Qp in dogs and decreases in arteriolar and venular diameters and intravascular volumetric flow (Qi) in rats. These responses were blocked by the alpha-antagonist PBZ. Activation of beta-receptors by intra-arterial injection of isoproterenal (ISO) caused a paradoxical reduction of Qp in dogs. In rats, ISO caused a transient increase in arteriolar Qi followed by a flow reduction; arteriolar dilation was accompanied by venular constriction. These macrocirculatory and microcirculatory responses to ISO were blocked by the alpha-antagonist propranolol.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-15

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

  1. Regional cerebral blood flow in status epileptics measured by single photon emission computed tomography (SPECT)

    International Nuclear Information System (INIS)

    Ichiseki, Hajime; Terashi, Akiro; Hamamoto, Makoto; Miyazaki, Tokuzo.

    1995-01-01

    We have performed single photon emission computed tomography (SPECT) with 99m Tc-hexamethylpropylene amineoxime (HM-PAO) to evaluate regional cerebral blood flow (rCBF) in status epileptics (SE) caused by a cerebral vascular accident. In addition, we have discussed the neurophysiology of SE based on the SPECT findings. A total of sixteen patients (5 males and 11 females, average age; 78.2 years old) with SE who were suffering from prolonged consciousness disturbance were investigated. When SPECT was performed in the ictal state, there was a remarkable increase in radio isotope (RI) uptake at the focus which correlated well with EEG findings. However, in other cortical regions, basal ganglia and thalamus, there was a relatively demonstrated decrease in RI uptake compared with that of the focus. Additionally in the interictal state, we found a decrease in RI uptake in the epileptic foci and normal recovery of the RI uptake level in other cerebral regions. We speculate that these characteristic patterns of cerebral blood flow distribution shown by SPECT scans in the ictal state reflect the state of consciousness disturbance due to SE. In general, in the elderly, it is difficult to make a differential diagnosis between prolonged consciousness disturbance due to nonconvulsive SE and other diseases such as cardiovascular diseases, dehydration, metabolic disorder, etc. Nevertheless, nonconvulsive SE causes diffuse cell loss and irreversible brain damage. Therefore the elderly who have suffered from prolonged consciousness disturbance due to SE need an exact diagnosis and immediate medical treatment. When we diagnose a nonconvulsive SE, the characteristic findings of SPECT scans in the ictal state are very clear and useful. In conclusion, SPECT is a very simple and non-invasive method that demonstrates abnormalities of brain function exactly. Therefore, we should perform not only EEC but also SPECT scans when making a diagnosis of SE. (author)

  2. Noninvasive regional cerebral blood flow measurements at pre- and post-acetazolamide test using 99mTc-ECD

    International Nuclear Information System (INIS)

    Matsuda, Hiroshi; Nakano, Seigo; Tanaka, Masaaki.

    1996-01-01

    A technique for serial noninvasive cerebral blood flow measurements at pre- and post-acetazolamide (Diamox) test was newly developed using 99m Tc-ECD without blood sampling. Baseline mean cerebral blood flow (mCBF) was measured from graphical analysis of time activity curves for brain and aortic arch obtained from radionuclide angiography by injection of 370-555 MBq 99m Tc-ECD. The first SPECT study was performed immediately after intravenous administration of 1 g of Diamox, then baseline regional cerebral blood flow (rCBF) was calculated using Lassen's correction algorithm. Immediately after the stop of the first SPECT study, additional 555-740 MBq of 99m Tc-ECD was administered, thereafter the second SPECT study was started. Post-Diamox SPECT images were obtained by subtraction of the first baseline images from the second images. Using Lassen's algorithm, post-Diamox mCBF was estimated from the baseline mCBF, the baseline mean SPECT counts, and post-Diamox mean SPECT counts corrected for administered dose and imaging time. Post-Diamox rCBF was obtained from the post-Diamox mCBF and the post-Diamox mean SPECT counts using Lassen's algorithm. Coefficient variation was shown 2.7% and 3.5%: mCBF and rCBF, respectively in test-retest results in six patients without Diamox administration. Nine demented patients without vascular disorders showed significant mCBF increase of 35.7% on the average by post-Diamox. In conclusion, this simplified method is practically useful for measuring CBF at pre- and post-Diamox test within short period of time without any blood sample. (author)

  3. Changes in Cerebral Blood Flow in Presymptomatic Mutation Carriers of Familial Frontotemporal Dementia (FTD-3), Measured with MRI

    DEFF Research Database (Denmark)

    Lunau, Line Andersen; Mouridsen, Kim; Rodell, Anders

    in the presymptomatic stage of the disease as indicated by local changes in cerebral blood flow (CBF). Methods: Presymptomatic mutation carriers and first-degree related non-carriers were MRI-scanned with a spin-echo sequence sensitive mainly to CBF in capillaries. CBF images were co-registered to structural T1-images...... decreased mean CBF values at the capillary level in all ROIs, with significant changes in capillary CBF in the parietal (mean change 14 %; p = 0.03) and occipital (mean change 9 %; p = 0.02) lobes. Conclusions: Decreased cerebral blood flow can be measured in presymptomatic CHMP2B mutation carriers...... with statistically significant differences in the occipital- and parietal lobes. Alterations in CBF possibly affect the whole brain. Data indicate that FTD-3 pathology might involve brain capillaries. This may impact the understanding of the pathogenesis involving endosomal dysfunction and implicates involvement...

  4. Influence of posture on hepatic blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Buchali, K.; Schimmelpfennig, W.; Sest, C.; Maluszek, S.; Sapia, C.; Correns, H.J.

    1980-08-01

    Hepatic blood flow was measured in 28 patients in supine and prone positions using the /sup 133/Xe-inhalation washout method. Even though the reactions in individual patients were considerably different, a mean blood flow of 60.9 ml/100 g/min was unaltered in both positions. This constancy of hepatic blood flow values is valid for patients without liver disease with chronic hepatitis, and with liver cirrhosis.

  5. Measurement of aortic blood flow by magnetic resonance below and above the origin of the coronary arteries in postmenopausal hormone replacement therapy

    DEFF Research Database (Denmark)

    Sørensen, Morten Beck; Fritz-Hansen, Thomas; Jensen, Henrik Halvor

    2004-01-01

    PURPOSE: Principal blood flow measures might be assessable by velocity-encoded cine magnetic resonance (VENC MR) of aortic blood flow. The feasibility of using VENC MR for clinical research was tested in a contemporary and controversial human model: the effects of 17beta-estradiol (E) and cyclic...

  6. Presymptomatic cerebral blood flow changes in CHMP2B mutation carriers of familial frontotemporal dementia (FTD-3), measured with MRI

    DEFF Research Database (Denmark)

    Lunau, Line Andersen; Mouridsen, Kim; Rodell, Anders

    2012-01-01

    OBJECTIVES: To assess functional changes measured by cerebral blood flow (CBF) in the presymptomatic stage of frontotemporal dementia linked to chromosome 3 (FTD-3) caused by a truncating mutation in CHMP2B. DESIGN: Case-control study. SETTING: A memory clinic and tertiary referrals centre...... changes in brain tissue perfusion were measured as CBF with two different MR techniques, gradient echo (GRE) and spin echo (SE), focusing on CBF in all cerebral vessels (GRE) and cerebral capillaries (SE), respectively. As planned, data analysis included co-registration of perfusion images to structural T...... indicate that FTD-3 vascular pathology might primarily affect brain capillaries....

  7. Significance of preoperative cerebral blood flow measurements in endovascular occlusion of the internal carotid and middle cerebral arteries

    International Nuclear Information System (INIS)

    Laurent, A.; Weitzner, I.; Luft, A.; Merland, J.J.

    1988-01-01

    Cerebral blood flow (CBF) measurements during 12 endovascular balloon occlusions (ten internal carotid and two middle cerebral arteries) with good clinical and angiographic tolerance were done with repeated boluses of Xe-133 injected directly into the ipsi- and contralateral carotid systems, during the occlusion and repeated measurements with detectors on both sides (before occlusion and 5-30 minutes after occlusion). In two cases of unchanged and four of increased CBF, one reversible deficit was probably due to an embolus. In six cases of decreased CBF, two deficits occurred, characterized by a greater than 25% decrease. It seems to represent a good predictive value for intolerance to occlusion

  8. Effect of Kanji and Kana reading on cerebral blood flow patterns measured by PET

    International Nuclear Information System (INIS)

    Kiyosawa, Motohiro; Itoh, Masatoshi; Nakagawa, Youichi; Kobayashi, Naoki; Tamai, Makoto.

    1995-01-01

    To investigate the respective functions of pathways in processing visual information from different types of symbols, by positron emission tomography (PET) we examined the effect on cerebral blood flow (CBF) of reading the Japanese morphogram (kanji) versus the syllabogram (kana). Nine Japanese men were presented with three visual conditions in random order 2 minutes before the scan: eyes open controls, kanji morphogram reading, and kana syllabogram reading. Three words written in kanji or kana were shown, and subjects were instructed to read them silently and to identify the word unrelated logically to the other two. The reading and analyzing tasks activated wide areas of vision-related cortices. The comparison of the kanji and kana readings showed higher metabolism, with the former only in the posterior part of the primary visual cortex. Most of the CBF increases were common for both stimuli, although the patterns of these increases differed slightly. The correlation matrix of CBF change in the left hemisphere showed a ventral connection in kanji reading and a dorsal connection in kana reading. Our results suggest there is a functional differentiation in the brain between patterned and sequential perception when reading Japanese morphograms and syllabograms. (author)

  9. Cerebral Blood Flow Measurements in Adults: A Review on the Effects of Dietary Factors and Exercise

    Directory of Open Access Journals (Sweden)

    Peter J. Joris

    2018-04-01

    Full Text Available Improving cerebrovascular function may be a key mechanism whereby a healthy lifestyle, of which a healthy diet combined with increased physical activity levels is a cornerstone, protects against cognitive impairments. In this respect, effects on cerebral blood flow (CBF—a sensitive physiological marker of cerebrovascular function—are of major interest. This review summarizes the impact of specific dietary determinants and physical exercise on CBF in adults and discusses the relation between these effects with potential changes in cognitive function. A limited number of randomized controlled trials have already demonstrated the beneficial effects of an acute intake of nitrate and polyphenols on CBF, but evidence for a relationship between these effects as well as improvements in cognitive functioning is limited. Moreover, long-term trans-resveratrol supplementation has been shown to increase CBF in populations at increased risk of accelerated cognitive decline. Long-term supplementation of n-3 long-chain polyunsaturated fatty acids may also increase CBF, but related effects on cognitive performance have not yet been found. Significant decreases in cerebral perfusion were observed by commonly consumed amounts of caffeine, while alcohol intake was shown to increase CBF in a dose-dependent way. However, the long-term effects are not clear. Finally, long-term exercise training may be a promising approach to improve CBF, as increases in perfusion may contribute to the beneficial effects on cognitive functioning observed following increased physical activity levels.

  10. Regional cerebral blood flow in schizophrenia

    International Nuclear Information System (INIS)

    Mathew, R.J.; Duncan, G.C.; Weinman, M.L.; Barr, D.L.

    1982-01-01

    Regional cerebral blood flow (rCBF) was measured via xenon133 inhalation technique in 23 patients with schizophrenia and 18 age- and sex-matched controls. The mean blood flow to both hemispheres was found to be lower for the patients. The patients and their controls did not differ on interhemispheric differences in blood flow. There were no differences in rCBF between medicated and unmedicated, subchronic and chronic, and paranoid and nonparanoid patients. Hallucinations were associated with reduced blood flow to several postcentral regions

  11. Regional brain blood flow in mouse: quantitative measurement using a single-pass radio-tracer method and a mathematical algorithm.

    Science.gov (United States)

    Xu, K; Radhakrishnan, K; Serhal, A; Allen, F; Lamanna, J C; Puchowicz, M A

    2011-01-01

    We have developed a reliable experimental method for measuring local regional cerebral blood flows in anesthetized mice. This method is an extension of the well-established single-pass dual-label indicator method for simultaneously measuring blood flow and glucose influx in rat brains. C57BL6J mice (n = 10) were anesthetized and regional blood flows (ml/min/g) were measured using the radio-tracer method. To test the sensitivity of this method we used a mathematical algorithm to predict the blood flows and compared the two sets of results.Measured regional blood flows between 0.7 and 1.7 ml/min/g were similar to those we have previously reported in the rat. The predicted blood flows using an assumed linearly increasing arterial tracer concentration-versus-time profile (that is, a ramp) were similar to the values measured in the physiological experiments (R(2) 0.99; slope 0.91). Thus,measurements of local regional cerebral blood flow in anesthetized mice using a single-pass radio-tracer method appear to be reliable.

  12. Blood flow and blood volume in a transplanted rat fibrosarcoma

    International Nuclear Information System (INIS)

    Tozer, G.M.; Morris, C.C.

    1990-01-01

    Blood flow measurements following i.v. infusion of iodi-antipyrine labelled with 14 C ( 14 C-IAP) and blood volume measurements following i.v. injection of 125 I human serum albumin and 51 Cr-labelled red blood cells were made in a transplanted rat fibrosarcoma for comparison with various normal tissues. The tumour-blood partition co-efficient for 14 C-IAP w as found to be 0.79 ± 0.07 which is similar to most of the normal tissues studied. The solubility of 14 C-IAP in plasma was found to be higher than that in whole blood. Blood flow to tumours 3 was found to be 17.9 ± 4.0 ml blood 100 g tissue -1 xmin -1 . These values were considered to be primarily measurements of nutritive flow. Blood in the tumours was found to occupy around 1% of the tissue space which was similar to that found for normal muscle and skin. There was no direct correlation between % blood volume and blood flow for the different tissues studied. Th haematocrit of blood contained in tumour tissue was calculated to be significantly lower than that of blood contained in the normal tissues. It was suspected that permeability of tumour blood vessel walls to 125 I-HSA could have accounted for this difference. (author). 41 refs.; 2 figs.; 3 tabs

  13. Microsphere estimates of blood flow: Methodological considerations

    International Nuclear Information System (INIS)

    von Ritter, C.; Hinder, R.A.; Womack, W.; Bauerfeind, P.; Fimmel, C.J.; Kvietys, P.R.; Granger, D.N.; Blum, A.L.

    1988-01-01

    The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 x 10 6 microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period

  14. Regional cerebral blood flow measurement using N-isopropyl-p-[123I] iodoamphetamine and rotating gamma camera emission computed tomography

    International Nuclear Information System (INIS)

    Matsuda, Hiroshi; Seki, Hiroyasu; Ishida, Hiroko

    1985-01-01

    Thirty-one regional cerebral blood flow (rCBF) measurements were performed on 26 patients with cerebrovascular accidents using N-Isopropyl-p-[ 123 I] Iodoamphetamine ( 123 I-IMP) and rotating gamma camera emission computed tomography (ECT). The equation for determining rCBF is as follows: F=100.R.Cb/(N.A), where F is rCBF in ml/100 g/min., R is the constant withdrawal rate of arterial blood in ml/min., Cb is the brain activity concentration in μCi/g, A is the total activity (5 min.) in the withdrawal arterial whole blood in μCi and N is the fraction of A that is true tracer activity (0.75). In determining Cb at 5 min. after injection, reconstructed counts from 35 min. to 59 min. were corrected to represent those from 4 min. to 5 min. with the use of time activity curve for the entire brain immediately after injection to 30 min. Reconstructed counts of central region in tomographic image were corrected 118% of the obtained values from the result of the countingrate ratio between peripheral and central regions of interests obtained from phantom study. Brain mean blood flow values were distributed from 11 to 39 ml/100 g/min. In 119 cortical regions obtained from 11 measurements in 9 patients, there was a significant correlation (r=0.41, p 123 I-IMP and rotating gamma camera ECT and those from 133 Xe inhalation method. rCBF measurement using 123 I-IMP and rotating gamma camera ECT is not only relatively noninvasive measurement for the entire brain but also three-dimensional evaluation. Besides, it is superior in spatial resolution and accuracy to conventional 133 Xe clearance method. (author)

  15. Serial measurement of regional cerebral blood flow in patients with SAH using 133Xe inhalation and emission computerized tomography

    DEFF Research Database (Denmark)

    Mickey, B; Vorstrup, S; Voldby, Bo

    1984-01-01

    A noninvasive three-dimensional method for measuring cerebral blood flow (CBF), xenon-133 inhalation and emission computerized tomography, was used to investigate the CBF changes accompanying delayed neurological deterioration following subarachnoid hemorrhage (SAH). A total of 67 measurements were...... performed on 20 patients in Hunt and Hess' clinical Grades I to III in the first 21 days post SAH. Five patients with normal CBF tomograms on admission developed delayed neurological deficits in the 2nd week after hemorrhage, at which time repeat CBF tomograms in four patients revealed large areas of well...... defined regional flow decrease in the vascular territories of the anterior or middle cerebral arteries. Severe vasospasm was noted in three of these patients in whom arteriography was performed in the 2nd week post SAH. Diffuse bihemispheric CBF decreases were noted later in the course of delayed...

  16. Postnatal changes in local cerebral blood flow measured by the quantitative autoradiographic [14C]iodoantipyrine technique in freely moving rats

    International Nuclear Information System (INIS)

    Nehlig, A.; Pereira de Vasconcelos, A.; Boyet, S.

    1989-01-01

    The postnatal changes in local cerebral blood flow in freely moving rats were measured by means of the quantitative autoradiographic [ 14 C]iodoantipyrine method. The animals were studied at 10, 14, 17, 21 and 35 days and at the adult stage. At 10 days after birth, rates of blood flow were very low and quite homogeneous in most cerebral structures except in a few posterior areas. From these relatively uniform levels, values of local cerebral blood flow rose notably to reach a peak at 17 days in all brain regions studied. Rates of blood flow decreased between 17 and 21 days after birth and then increased from weaning time to reach the known characteristic distribution of the adult rat. The postnatal evolution of local cerebral blood in the rat is in good agreement with previous studies in other species such as dog and humans that also show higher rates of cerebral blood flow and glucose utilization at immature stages. However, in the rat, local cerebral blood flow and local cerebral glucose utilization are not coupled over the whole postnatal period studied, since blood flow rates reach peak values at 17 days whereas glucose utilization remains still quite low at that stage. The high rate of cerebral blood flow in the 17-day-old rat may reflect the energetic and biosynthetic needs of the actively developing brain that are completed by the summation of glucose and ketone body utilization

  17. Bone blood flow and metabolism in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Kemppainen, Jukka; Kaskinoro, Kimmo

    2012-01-01

    Human bone blood flow and metabolism during physical exercise remains poorly characterised. In the present study we measured femoral bone blood flow and glucose uptake in young healthy subjects by positron emission tomography in three separate protocols. In six women, blood flow was measured...... in femoral bone at rest and during one leg intermittent isometric exercise with increasing exercise intensities. In nine men, blood flow in femur was determined at rest and during dynamic one leg exercise, and two other physiological perturbations: moderate systemic hypoxia (14 O(2) ) at rest and during...... exercise, and during intra-femoral infusion of high-dose adenosine. Bone glucose uptake was measured at rest and during dynamic one leg exercise in five men. The results indicate that isometric exercise increased femoral bone blood flow from rest (1.8 ± 0.6 ml/100g/min) to low intensity exercise (4.1 ± 1...

  18. Laser speckle contrast imaging of blood flow from anesthetized mice: correcting drifts in measurements due to breathing movements

    Science.gov (United States)

    Nogueira, Gesse E. C.; Ribeiro, Márcio A. C.; Campos, Juliane C.; Ferreira, Julio C. B.

    2015-06-01

    Background: Laser speckle contrast imaging allows non-invasive assessment of cutaneous blood flow. Although the technique is attractive to measure a quantity related to the skin blood flow (SBF) in anesthetized animal models, movements from breathing can mask the SBF signal. As a consequence, the measurement is overestimated because a variable amount of a DC component due to the breathing movements is added to the SBF signal. Objective: To evaluate a method for estimating the background level of the SBF signal, rejecting artefacts from breathing. Methods: A baseline correction method used for accurate DNA sequencing was evaluated, based on estimating the background level of a signal in small temporal sliding-windows. The method was applied to evaluate a mouse model of hindlimb ischemia. SBF signals from hindlimbs of anesthetized C57BL/6 mice (n=13) were registered. The mean SBF (Fi and Fc from ischemic and control hindlimbs) were computed from the registers and from the corresponding estimated background levels (Fib and Fcb from ischemic and control hindlimbs). Results: The mean values of the percentages (a measure of ischemia) MI = (Fi/Fc).100 and MIb = (Fib/Fcb).100 were computed to be 30+/-4% and 23+/-3% respectively (mean +/- SE). Evidences of statistical differences between both, ischemic and control hindlimbs, were obtained (pcorrupted SBF signal by breathing artefacts is feasible, allowing more accurate measurements.

  19. Endoscopic Doppler ultrasound for measurement of azygos blood flow. Validation against thermodilution and assessment of pharmacological effects of terlipressin in portal hypertension

    DEFF Research Database (Denmark)

    Hansen, Erik Feldager; Bendtsen, Flemming; Brinch, K

    2001-01-01

    administration of terlipressin, the azygos blood flow, as measured by EUS Doppler, decreased significantly by 23% from 915 to 704 ml/min (P = 0.014) and the portal venous flow decreased by 28% from 1170 to 789 ml/min (P = 0.03). No effects of placebo were detected. CONCLUSIONS: These results show that EUS...... measurement of the azygos blood flow correlate strongly to the measurements by the thermodilution technique, and EUS is moreover well tolerated by the patients. The method is applicable for monitoring pharmacological effects on the superior porto-systemic collateral circulation and portal venous flow...

  20. Simultaneous measurement of cerebral blood flow and oxygen extraction fraction by positron emission tomography: theoretical study and experimental evidence of cerebral blood flow measurement with the C15O2 continuous inhalation technique

    International Nuclear Information System (INIS)

    Steinling, M.

    1983-01-01

    The method of the continuous inhalation technique of oxygen-15 labelled CO 2 coupled with positron emission tomography for the measurement of cerebral blood flow (C.B.F.) is described. An indirect experimental verification that this technique allowed the measurement of C.B.F. has been carried out in baboons by showing the expected change in the measured parameter with variations in the PaCO 2 . A critical investigation of the C 15 O 2 model was performed. The amount of tracer present in the cerebral vascular pool has a negligible effect on C.B.F. value. The use of a mean brain-blood partition coefficient of water instead of that specific to gray or to white matter is commented upon, and its influence on the final C.B.F. value is studied. Lastly, the problem of the limited diffusion of water across the blood-brain-barrier is discussed. The study of the combined effects of gray-white mixing and limited wates extraction of the C.B.F. value shows that the C 15 O 2 technique tends to understimate real C.B.F., and that this error is more severe with high flows and even gray white mixing. These limitations do not depart from the possibility to estimate in the same brain locus not only C.B.F. but oxygen utilization as well by the consecutive inhalation of C 15 O 2 and 15 O 2 . The advantages of this possibility has already been shown in a number of clinical studies [fr

  1. Label free imaging system for measuring blood flow speeds using a single multi-mode optical fiber (Conference Presentation)

    Science.gov (United States)

    Sigal, Iliya; Caravaca Aguirre, Antonio M.; Gad, Raanan; Piestun, Rafael; Levi, Ofer

    2016-03-01

    We demonstrate a single multi-mode fiber-based micro-endoscope for measuring blood flow speeds. We use the transmission-matrix wavefront shaping approach to calibrate the multi-mode fiber and raster-scan a focal spot across the distal fiber facet, imaging the cross-polarized back-reflected light at the proximal facet using a camera. This setup allows assessment of the backscattered photon statistics: by computing the mean speckle contrast values across the proximal fiber facet we show that spatially-resolved flow speed maps can be inferred by selecting an appropriate camera integration time. The proposed system is promising for minimally-invasive studies of neurovascular coupling in deep brain structures.

  2. An account of the discrepancy between MRI and PET cerebral blood flow measures. A high-field MRI investigation.

    Science.gov (United States)

    Donahue, Manus J; Lu, Hanzhang; Jones, Craig K; Pekar, James J; van Zijl, Peter C M

    2006-12-01

    There is controversy concerning the discrepancy between absolute cerebral blood flow (CBF) values measured using positron emission tomography (PET) and magnetic resonance imaging (MRI). To gain insight into this problem, the increased signal-to-noise ratio (SNR) and extended T(1) relaxation times of blood and tissue at 3.0 T were exploited to perform pulsed arterial spin labeling (PASL) MRI measurements as a function of spatial resolution and post-labeling delay. The results indicate that, when using post-labeling delays shorter than 1500 ms, MRI gray matter flow values may become as high as several times the correct CBF values owing to tissue signal contamination by remaining arterial blood water label. For delays above 1500 ms, regional PASL-based CBF values (n = 5; frontal gray matter: 48.8 +/- 3.3(SD) ml/100 g/min; occipital gray matter: 49.3 +/- 4.5 ml/100 g/min) comparable with PET-based measurements can be obtained by using spatial resolutions comparable with PET (5-7.5 mm in-plane). At very high resolution (2.5 x 2.5 x 3 mm(3)), gray matter CBF values were found to increase by 10-20%, a consequence attributed to reduction in partial volume effects with cerebrospinal fluid and white matter. The recent availability of MRI field strengths of 3.0 T and higher will facilitate the use of MRI-based CBF measurements in the clinic. Copyright (c) 2006 John Wiley & Sons, Ltd.

  3. Measurement of hepatic volume and effective blood flow with radioactive colloids: Evaluation of development in liver diseases

    International Nuclear Information System (INIS)

    Fujii, M.; Uchino, H.; Kyoto Univ.

    1982-01-01

    Changes in hepatic volume and the blood flow effectively perfusing the liver parenchyma were studied as an assessment of the severity of liver diseases. Hepatic effective blood flow was estimated as the hepatic fractional clearance of radioactive colloids, obtained from the disappearance rate multiplied by the fraction of injected dose taken up by the liver. The hepatic fractional clearance was normal or not markedly decreased in patients with acute hepatitis which had developed favorably, but was severely decreased in patients with fulminant hepatitis. In liver diseases, the ratio of hepatic volume to fractional clearance was found to increase as the clearance decreased. In subjects with normal clearance, hepatic fractional clearance was correlated significantly with liver volume, indicating that hepatic effective blood flow is proportional to parenchymal volume in an unanesthetized, resting state. In biopsied cases changes in volume and blood flow accorded well with changes indicated by morphological criteria. In chronic persistent hepatitis, effective hepatic blood flow is not diminished. However, hepatic blood flow were observed between the cirrhosis or chronic aggressive hepatitis, and normal control groups. Extension of chronic inflammatory infiltration into the parenchyma distinguishes chronic aggressive hepatitis from chronic persistent hepatitis. Architecture is often disturbed in the former. These changes should be accompanied by disturbance of microcirculation. The present study indicates that the decrease in effective hepatic blood flow in chronic hepatitis and cirrhosis has two aspects: one is a summation of microcirculatory disturbances, and the other is a decrease in liver cell mass. (orig.)

  4. Comparison of ASL and DCE MRI for the non-invasive measurement of renal blood flow: quantification and reproducibility

    International Nuclear Information System (INIS)

    Cutajar, Marica; Hales, Patrick W.; Clark, Christopher A.; Gordon, Isky; Thomas, David L.; Banks, T.

    2014-01-01

    To investigate the reproducibility of arterial spin labelling (ASL) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and quantitatively compare these techniques for the measurement of renal blood flow (RBF). Sixteen healthy volunteers were examined on two different occasions. ASL was performed using a multi-TI FAIR labelling scheme with a segmented 3D-GRASE imaging module. DCE MRI was performed using a 3D-FLASH pulse sequence. A Bland-Altman analysis was used to assess repeatability of each technique, and determine the degree of correspondence between the two methods. The overall mean cortical renal blood flow (RBF) of the ASL group was 263 ± 41 ml min -1 [100 ml tissue] -1 , and using DCE MRI was 287 ± 70 ml min -1 [100 ml tissue] -1 . The group coefficient of variation (CV g ) was 18 % for ASL and 28 % for DCE-MRI. Repeatability studies showed that ASL was more reproducible than DCE with CV g s of 16 % and 25 % for ASL and DCE respectively. Bland-Altman analysis comparing the two techniques showed a good agreement. The repeated measures analysis shows that the ASL technique has better reproducibility than DCE-MRI. Difference analysis shows no significant difference between the RBF values of the two techniques. (orig.)

  5. Relations between neuropsychological findings and lateral asymmetries of cerebral blood flow measured by SPECT in dementia of Alzheimer type

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Nahoko; Soma, Yoshiaki; Ootsuki, Mika [Takeda General Hospital, Aizu-Wakamatsu, Fukushima (Japan)

    1993-10-01

    We studied 16 right-handed patients clinically diagnosed as dementia of Alzheimer type (6 men, 10 women; aged 63-85, mean 72.8 years). The average duration of symptoms was 2.7 years. Dementia ranged from mild to moderately severe. None had clinical or laboratory evidence of cerebrovascular disease (Hachinski ischemic scores for all patients were 4 or below 4). All received the Wechsler Adult Intelligence Scale (WAIS), Mini-mental State Test (MMS) and Western Aphasia Battery (WAB, First Japanese edition, 1986). Regional cerebral blood flow (rCBF) was evaluated by single photon emission CT (SPECT) with {sup 123}I-N-isopropyl-p-iodoamphetamine ({sup 123}I-IMP), using the Matsuda`s quantitative method. Regional tracer uptake was measured in regions of interests (ROIs) over right and left frontal, temporal, parietal and occipital cortical regions; basal ganglia; and cerebellar hemispheres. The subjects were divided into three groups on the basis of lateral asymmetries in the temporal and parietal cortexes of rCBF (leftblood flow. Verbal IQ in patients with predominant hypoperfusion of left temporal and parietal lobe was significantly lower than other group, while performance IQ and WAB constructive scores were lower in those with right hemispheric hypoperfusion (p<0.05). We concluded that cerebral blood flow asymmetry by SPECT was related significantly to the deficit of language and constructive function in patients with dementia of Alzheimer type. Decreased rCBF in the left temporoparietal lobe was associated with language dysfunction, and that in the right hemisphere, with constructive dysfunction. (author).

  6. Brachial blood flow under relative levels of blood flow restriction is decreased in a nonlinear fashion.

    Science.gov (United States)

    Mouser, J Grant; Ade, Carl J; Black, Christopher D; Bemben, Debra A; Bemben, Michael G

    2018-05-01

    Blood flow restriction (BFR), the application of external pressure to occlude venous return and restrict arterial inflow, has been shown to increase muscular size and strength when combined with low-load resistance exercise. BFR in the research setting uses a wide range of pressures, applying a pressure based upon an individual's systolic pressure or a percentage of occlusion pressure; not a directly determined reduction in blood flow. The relationship between relative pressure and blood flow has not been established. To measure blood flow in the arm under relative levels of BFR. Forty-five people (18-40 years old) participated. Arterial occlusion pressure in the right arm was measured using a 5-cm pneumatic cuff. Blood flow in the brachial artery was measured at rest and at pressures between 10% and 90% of occlusion using ultrasound. Blood flow decreased in a nonlinear, stepped fashion. Blood flow decreased at 10% of occlusion and remained constant until decreasing again at 40%, where it remained until 90% of occlusion. The decrease in brachial blood flow is not proportional to the applied relative pressure. The prescription of blood flow restriction should take into account the stimulus provided at each relative level of blood flow. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  7. Imaging of Neuronal Activity in Awake Mice by Measurements of Flavoprotein Autofluorescence Corrected for Cerebral Blood Flow

    Directory of Open Access Journals (Sweden)

    Manami Takahashi

    2018-01-01

    Full Text Available Green fluorescence imaging (e.g., flavoprotein autofluorescence imaging, FAI can be used to measure neuronal activity and oxygen metabolism in living brains without expressing fluorescence proteins. It is useful for understanding the mechanism of various brain functions and their abnormalities in age-related brain diseases. However, hemoglobin in cerebral blood vessels absorbs green fluorescence, hampering accurate assessments of brain function in animal models with cerebral blood vessel dysfunctions and subsequent cerebral blood flow (CBF alterations. In the present study, we developed a new method to correct FAI signals for hemoglobin-dependent green fluorescence reductions by simultaneous measurements of green fluorescence and intrinsic optical signals. Intrinsic optical imaging enabled evaluations of light absorption and scatters by hemoglobin, which could then be applied to corrections of green fluorescence intensities. Using this method, enhanced flavoprotein autofluorescence by sensory stimuli was successfully detected in the brains of awake mice, despite increases of CBF, and hemoglobin interference. Moreover, flavoprotein autofluorescence could be properly quantified in a resting state and during sensory stimulation by a CO2 inhalation challenge, which modified vascular responses without overtly affecting neuronal activities. The flavoprotein autofluorescence signal data obtained here were in good agreement with the previous findings from a condition with drug-induced blockade of cerebral vasodilation, justifying the current assaying methodology. Application of this technology to studies on animal models of brain diseases with possible changes of CBF, including age-related neurological disorders, would provide better understanding of the mechanisms of neurovascular coupling in pathological circumstances.

  8. Cerebral blood flow measured by positron emission tomography during normothermic cardiopulmonary bypass

    DEFF Research Database (Denmark)

    Thomassen, Sisse Anette; Kjærgaard, Benedict; Alstrup, Aage Kristian Olsen

    2018-01-01

    emission tomography (PET) using 15O-labelled water with no pharmacological interventions to maintain the MAP. METHODS: Eight pigs (69-71 kg) were connected to normothermic CPB. After 60 minutes (min) with a CPB pump flow of 60 mL/kg/min, the pigs were changed to either 35 mL/kg/min or 47.5 mL/kg/min for 60...... to complications. CBF increased from spontaneous circulation to a CPB pump flow of 60 mL/kg/min. A reduction in CPB pump flow to 47.5 mL/kg/min (n=3) resulted in only minor changes in CBF while a reduction to 35 mL/kg/min (n=3) caused a pronounced change (correlation coefficient (R2) 0.56). A return of CPB pump...

  9. SPECT with [99mTc]-d,l-hexamethyl-propylene amine oxime (HM-PAO) compared with regional cerebral blood flow measured by PET

    DEFF Research Database (Denmark)

    Yonekura, Y; Nishizawa, S; Mukai, Thomas Søgaard

    1988-01-01

    In order to validate the use of technetium-99m-d,l-hexamethylpropyleneamine oxime (HM-PAO) as a flow tracer, a total of 21 cases were studied with single photon emission computerized tomography (SPECT), and compared to regional cerebral blood flow (rCBF) measured by position emission tomography (...

  10. Comparison of uteroplacental blood flow in normal and pre-eclamptic patients measurement with technetium-99m and a computer-linked gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S.H.; Moon, H.; Kim, D.S.; Cho, S.S.

    1985-05-01

    Uteroplacental blood flow studies in preeclampsia are of special interest since the vascular changes reported in this disease might constitute a structural basis for a reduction of blood flow. Evidence has also been given for a decreased uteroplacental blood flow in preeclampsia. Among the various methods to estimate the maternal placental blood flow, the one most frequently reported in the literature during the last years has been the time activity analysis of short lived radiotracer such as technetium-99m or indium-113m injected intravenously. Only few studies with the above mentioned technique comparing normal and preeclampsia cases have been undertaken. In clinical practice we frequently experience difficuly in finding the optimal time to get the delivery in preeclampsia patients. The aim of this study was first to measure uteroplacental blood flow in preeclamptic pregnancies using a computer-linked gamma camera method for the time-activity analysis of technetium-99m and second to discuss the possibility of clinical application of these measurements for determination of fetal well-being and the timing of the delivery in these patients. Uteroplacental blood flow was measured from 13 preeclamptic patients and 19 pregnancies without any complication after 35 completed weeks of gestation from Jan. 1983 to Sep. 1983 at Obstetrics department of Hanyang University Hospital. (Author).

  11. Renal blood flow and metabolism after cold ischaemia: peroperative measurements in patients with calculi

    DEFF Research Database (Denmark)

    Petersen, H K; Henriksen, Jens Henrik Sahl

    1984-01-01

    and renal venous L/P ratio were almost constant, indicating no significant anaerobic processes being involved in the flow response. None of the patients showed any signs of reactive hyperaemia. It is concluded that hypothermic renal ischaemia may be followed by an increased renal vascular resistance even.......01) immediately after re-established perfusion and 36% (P less than 0.02) 30 min later. In one additional patient, who had a short warm ischaemia (8 min), the flow pattern was the same. As arterial pressure remained constant, the reduced RBF signifies an increased renal vascular resistance. Renal O2-uptake...... when signs of anaerobic metabolism are sparse or absent. This conception is in contrast to that gained from previous animal experiments where anaerobic processes are kept responsible for the changes. The mechanism behind the described response is unknown, but the changes are probably reversible....

  12. Cerebral blood-flow measurements with Tc-99m HMPAO and I-123 HIPDM in patients with cerebral tumors

    International Nuclear Information System (INIS)

    Maier-Hauff, K.; Cordes, M.; Sprung, Ch.; Gerlach, L.; Baerwald, R.

    1988-01-01

    In a study of 47 patients with brain tumors (12 meningiomas, 29 gliomas, four metastases, two lymphomas), the cerebral uptake of Tc-99m HMPAO and I-123 HIPDM were measured within the tumor and edema area. The meningioma, lymphoma, and metastases group showed increased regional cerebral blood flow (rCBF) with both methods in contrast to the low-grade gliomas, with a decreased tracer uptake. In high-grade gliomas, hypoperfusion was seen in ten of 18 cases with HMPAO and four of 18 with HIPDM. The rCBF in perifocal edema showed a low perfusion rate in all cases. In contrast to other investigators, the authors found a typical perfusion pattern in grade III and IV gliomas. The recent results demonstrate that the SPECT methods play an important role in the planning of radiation therapy and chemotherapy for malignant brain tumors

  13. Measurement of local blood flow and oxygen consumption in evolving irreversible cerebral infarction: an in vivo study in man

    International Nuclear Information System (INIS)

    Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Bousser, M.G.; Cabanis, E.; Bories, J.; Comar, D.; Castaigne, P.

    1982-09-01

    Positron emission tomography (PET) allows in vivo measurement of local cerebral blood flow (1CBF), oxygen consumption rate (1CMRO 2 ) and glucose utilisation (1CMRG1c) in man. Although 1CMRG1c is accessible in animals, this is not the case for 1CMRO 2 , an excellent index of local functional state. PET imaging of the local interrelationship of CBF and metabolism in completed ischemic stroke has attracted considerable interest because of its potential to differentiate irreversibly damaged from viable tissue on the basis of the CBF- metabolism patterns. Several qualitative or semi-quantitative pioneering studies provided a limited insight into this question, while the single truly quantitative study was only briefly reported. We report here a detailed study of the local CBF-CMRO 2 quantitative patterns in irreversibly infarcted brain regions

  14. MR velocity mapping measurement of renal artery blood flow in patients with impaired kidney function

    DEFF Research Database (Denmark)

    Cortsen, M; Petersen, L.J.; Stahlberg, F

    1996-01-01

    . MR velocity mapping was performed in both renal arteries using an ECG-triggered gradient echo pulse sequence previously validated in normal volunteers. Effective renal plasma flow was calculated from the clearance rate of PAH during constant infusion and the split of renal function was evaluated...... by 99mTc-DTPA scintigraphy. A reduction of RBF was found, and there was a significant correlation between PAH clearance multiplied by 1/(1-hematocrit) and RBF determined by MR velocity mapping. Furthermore, a significant correlation between the distribution of renal function and the percent distribution...

  15. Blood flow autoregulation in pedicled flaps

    DEFF Research Database (Denmark)

    Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

    2009-01-01

    INTRODUCTION: Clinical work on the blood perfusion in skin and muscle flaps has suggested that some degree of blood flow autoregulation exists in such flaps. An autoregulatory mechanism would enable the flap to protect itself from changes in the perfusion pressure. The purpose of the present study...... was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......-type calcium channel blocker nimodipine and the vasodilator papaverine. MATERIAL AND METHODS: Pedicled flaps were raised in pigs. Flow in the pedicle was reduced by constriction of the feed artery (n=34). A transit time flow probe measured the effect on blood flow continuously. Following this, three different...

  16. Measurement of cardiac valve and aortic blood flow velocities in stroke patients: a comparison of 4D flow MRI and echocardiography.

    Science.gov (United States)

    Wehrum, Thomas; Guenther, Felix; Fuchs, Alexander; Schuchardt, Florian; Hennemuth, Anja; Harloff, Andreas

    2018-01-11

    4D flow MRI is an emerging technique that allows quantification of 3D blood flow in vivo. However, comparisons with methods of blood velocity quantification used in clinical routine are sparse. Therefore, we compared velocity quantification using 4D flow MRI with transthoracic and transesophageal echocardiography at the mitral and aortic valves and the aorta. Forty-eight stroke patients (age 67.3 ± 15.0 years) were examined by 4D flow MRI. Blood flow velocities were assessed using standardized 2D analysis planes positioned in the mitral valve (MV), aortic valve (AV), ascending aorta (AAo), and descending aorta (DAo) and were compared with echocardiography. MRI showed moderate-high correlations of systolic velocity values for the MV (r = 0.67, p flow velocities compared with echocardiography by 8.6% for the MV (p = 0.07), 3.1% for the AV (p = 0.48), 10.7% for the AAo (p = 0.09), and 15.0% for the DAo (p = 0.01). Blood flow velocities obtained using 4D flow MRI and echocardiography at the MV, AV, and the ascending and DAo showed moderate to high correlations. Underestimation of absolute velocity values by MRI was low. Thus, 4D flow MRI seems ideally suited to comprehensively assess cardiac and aortic pathologies and related hemodynamic changes in future studies.

  17. Postradiation regional cerebral blood flow in primates

    International Nuclear Information System (INIS)

    Cockerham, L.G.; Cerveny, T.J.; Hampton, J.D.

    1986-01-01

    Early transient incapacitation (ETI) is the complete cessation of performance during the first 30 min after radiation exposure and performance decrement (PD) is a reduction in performance at the same time. Supralethal doses of radiation have been shown to produce a marked decrease in regional cerebral blood flow in primates concurrent with hypotension and a dramatic release of mast cell histamine. In an attempt to elucidate mechanisms underlying the radiation-induced ETI/PD phenomenon and the postradiation decrease in cerebral blood flow, primates were exposed to 100 Gy (1 Gy = 100 rads), whole-body, gamma radiation. Pontine and cortical blood flows were measured by hydrogen clearance, before and after radiation exposure. Systemic blood pressures were determined simultaneously. Systemic arterial histamine levels were determined preradiation and postradiation. Data obtained indicated that radiated animals showed a decrease in blood flow of 63% in the motor cortex and 51% in the pons by 10 min postradiation. Regional cerebral blood flow of radiated animals showed a slight recovery 20 min postradiation, followed by a fall to the 10 min nadir by 60 min postradiation. Immediately, postradiation systemic blood pressure fell 67% and remained at that level for the remainder of the experiment. Histamine levels in the radiated animals increased a hundredfold 2 min postradiation. This study indicates that regional cerebral blood flow decreases postradiation with the development of hypotension and may be associated temporally with the postradiation release of histamine

  18. Effect of prewarming the forearm on the measurement of regional cerebral blood flow with one-point venous sampling by autoradiography method

    International Nuclear Information System (INIS)

    Itoh, Youko H.; Kurabe, Teruhisa; Kazaoka, Yoshiaki; Ishiguchi, Tsuneo; Kawashima, Sadao

    2004-01-01

    Autoradiography (ARG) using 123 I-iodoamphetamine ( 123 I-IMP) is widely performed as an efficient method of measuring local cerebral blood flow. Recently, ARG by a single collection of venous blood has been appreciated as a simple method. In this study, we investigated the effect of warming of the site for collecting venous blood (forearm). The coefficient of correlation of the local cerebral blood flow value obtained from arterial and venous blood samples was 0.766 (p<0.05) in the group without warming (38 patients). The coefficient of correlation similarly obtained in the group with warming (53 patients) was 0.908 (p<0.05). The difference in the correlation efficient was significant (p<0.05) between the two groups. From these results it was concluded that warming the blood-collecting site decreased the difference between the arterial and venous radioactive concentrations and increased the precision of the test. (author)

  19. Regional cerebral blood flow measurements in schizophrenics by /sup 133/Xe inhalation and intra-venous injection method

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Hiroshi; Seki, Hiroyasu; Sumiya, Hisashi; Ishida, Hiroko; Taki, Junichi; Hisada, Kinichi; Kurachi, Masayoshi; Kobayashi, Katsuji; Yamaguchi, Nariyoshi (Kanazawa Univ. (Japan). School of Medicine)

    1984-12-01

    Regional cerebral blood flow measurements were performed in 25 schizophrenic patients and 25 healthy volunteers by /sup 133/Xe inhalation and intra-venous injection method. Schizophrenic patients were classified into the following three groups. Group I: 8 patients without auditory hallucination measured by 2-dimensional /sup 133/Xe inhalation method. Group II: 6 patients with auditory hallucination measured by the same method as in Group I. Group III: 11 patients, including 2 patients with auditory hallucination measured by 3-dimensional /sup 133/Xe intra-venous injection method at the level of OM+5 cm. Bilateral regional percent values, which were obtained by dividing regional values by hemispheric mean or sectional mean values, for frontal lobes in Group I and II were significantly lower than those in the controls. In addition, bilateral regional percent values for bilateral temporal lobes in Group II were significantly higher than those in the controls. In Group III, regional percent values for right frontal lobes and those for posterior part of central gray matter showed significant decrease and increase, respectively. These findings would suggest that the negative symptoms of schizophrenia are related to the hypofrontal and positive ones to the hypertemporoparietal activity.

  20. Cerebral blood flow measurement using 123I-IMP graph plot method with SPECT. Comparison with autoradiography method

    International Nuclear Information System (INIS)

    Shinohara, Yuki; Kamitani, Hideki; Ishibashi, Minako; Ito, Satoru; Ogawa, Toshihide

    2011-01-01

    The purpose of this study was to evaluate quantification of cerebral blood flow (CBF) values using 123 I-iodoamphetamine (IMP) graph plot (GP) method with single photon emission computed tomography (SPECT), compared with autoradiography (ARG) method. IMP-SPECT by GP combined with ARG method at rest was performed in 40 patients to determine the equation of linear regression for GP method in our institution. In addition, we compared regional CBF (rCBF) values at rest between GP and ARG methods in 10 other patients. Among all 50 patients, acetazolamide (ACZ)-challenged SPECT by GP combined with ARG method using 2-day protocol was performed in 10 patients. We also compared the rCBF values after ACZ challenge between GP and ARG methods in these 10 patients. The equation of linear regression for GP method in our institution was y=1.945x+20.36 (R 2 =0.586, P 2 =0.624, P 2 =0.150, P<0.001). IMP-SPECT by GP method at rest is useful to measure reliable rCBF values without arterial blood sampling, although we need pay attention to interpret the result of 2-day protocol ACZ-challenged SPECT by GP method. (author)

  1. Effect of Post-Reconstruction Gaussian Filtering on Image Quality and Myocardial Blood Flow Measurement with N-13 Ammonia PET.

    Science.gov (United States)

    Kim, Hyeon Sik; Cho, Sang-Geon; Kim, Ju Han; Kwon, Seong Young; Lee, Byeong-Il; Bom, Hee-Seung

    2014-01-01

    In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF) measurement by dynamic N-13 ammonia positron emission tomography (PET), we compared various reconstruction and filtering methods with image characteristics. Dynamic PET images of three patients with coronary artery disease (male-female ratio of 2:1; age: 57, 53, and 76 years) were reconstructed, using filtered back projection (FBP) and ordered subset expectation maximization (OSEM) methods. OSEM reconstruction consisted of OSEM_2I, OSEM_4I, and OSEM_6I with 2, 4, and 6 iterations, respectively. The images, reconstructed and filtered by Gaussian filters of 5, 10, and 15 mm, were obtained, as well as non-filtered images. Visual analysis of image quality (IQ) was performed using a 3-grade scoring system by 2 independent readers, blinded to the reconstruction and filtering methods of stress images. Then, signal-to-noise ratio (SNR) was calculated by noise and contrast recovery (CR). Stress and rest MBF and coronary flow reserve (CFR) were obtained for each method. IQ scores, stress and rest MBF, and CFR were compared between the methods, using Chi-square and Kruskal-Wallis tests. In the visual analysis, IQ was significantly higher by 10 mm Gaussian filtering, compared to other sizes of filter (PPost-reconstruction Gaussian filtering with a filter size of 10 mm significantly enhances the IQ of N-13 ammonia PET-CT, without changing the results of CFR calculation.

  2. Measurement of renal blood flow by 131I-labelled sodium iodohippurate imaging in a rat model of herpes encephalitis

    International Nuclear Information System (INIS)

    Cleator, G.M.; Klapper, P.E.; Lewis, A.G.; Sharma, H.L.; Smith, A.M.; Manchester Univ.

    1990-01-01

    Renal blood flow was assessed qualitatively over a 30 min period in a rat model of herpes encephalitis by extra-renal scintigraphic imaging following the injection of 131 I-labelled sodium iodohippurate. No significant differences were observed for renal blood flow in either kidney between (or within) infected and control groups. Our data suggest that kidney function is not compromised in this animal model of encephalitis. The results are discussed in the context of the development of a non-invasive protocol for the in vivo diagnosis of herpes encephalitis. (orig.)

  3. Measurement of regional cerebral blood flow with single photon emission computed tomography in patients with aphasia

    International Nuclear Information System (INIS)

    Reischies, F.M.; Muellmann, A.; Hedde, J.P.; Freie Univ. Berlin; Christe, W.

    1984-01-01

    5 cases are demonstrated of patients with aphasia whose brain perfusion as measured regionally by SPECT using 133 Xe was correlated to the lesions seen in the CT study. Perfusion reductions exceeded the CT visible lesions, such as, that in cortical lesions perfusion in the region of basal ganglia is diminished and vice versa. The findings are discussed in relation to recent work on brain perfusion and metabolism. (orig.) [de

  4. Molecular versus particulate deposition markers for blood flow measurement in the musculo-skeletal system. 131Iodo-DesMethyl-Imipramine

    International Nuclear Information System (INIS)

    Tromborg, H.B.

    1998-01-01

    The aims of the experiments were to develop and validate a porcine isolated blood perfused myocutaneous flap and tibia model with preserved venous outflow. The stability of the models was tested and washout of microspheres and IDMI was measured. IDMI and microsphere based tissue blood flow measurements were compared after central intracardiac injection into the intact animal. Three experimental series were necessary to develop and validate the models. The organs were perfused with arterial blood by a pulsatile pump and submerged into a tissue bath. All outflow from the models were collected. One experiment was necessary to validate the rectus abdominis myocutaneous flap. In three experiments an isolated tibia with preserved venous outflow was developed and validated. Normal flow rate/perfusion pressure relations were reproduced after periods of supra-normal and sub-normal perfusion pressure in the two models. A response to endothelially mediated vasodilation with bradykinin was demonstrated after nine hours of artificial perfusion in the tibia model. IDMI did not influence the local hemodynamics during infusion, whereas microspheres elicited a transitory increase in the perfusion pressure after local injection. IDMI and microsphere based blood flow measurements and recirculation were compared in the in-situ musculo-skeletal tissue corresponding to the two models after central injection of the markers. Recirculation of IDMI was greater (8(1)%) than that of microspheres (2(0)%) after 18 minutes. Microspheres tended to measure higher blood flow values than IDMI at high flow rates and vice versa at low flow values. The 131 Iodo-DesMethyl-Imipramine (IDMI) method is not generally applicable as a deposition marker for blood flow measurement in the musculo-skeletal system. (EHS)

  5. Application of carbon-11 labelled nicotine in the measurement of human cerebral blood flow and other physiological parameters

    International Nuclear Information System (INIS)

    Yokoi, Fuji; Hayashi, Tokishi; Iio, Masaaki; Hara, Toshihiko

    1993-01-01

    Using positron emission tomography (PET), we measured the regional cerebral blood flow (rCBF) in five normal human subjects after intravenous injection of carbon-11 labelled (R)nicotine. The rCBF of the same subjects was measured by PET using the C 15 O 2 inhalation steady-state method. The distribution of 11 C activity in the brain after injection of 11 C-(R)nicotine was almost equivalent to the CBF image obtaines with C 15 O 2 inhalation steady-state method. The kinetics of 11 C-(R)nicotine in the brain was analysed using a two-compartment model consisting of vascular and brain tissue compartments. The rCBF values obtained with 11 C-(R)nicotine were higher than with C 15 O 2 gas. It is possible that the relatively long fixed distribution of 11 C-(R)nicotine with a short uptake period allows stimulation studies by measurement of CBF to be performed with better photon flux and a longer imaging time than are possible with H 2 15 O. (orig.)

  6. Prediction of effectiveness of shunting in patients with normal pressure hydrocephalus by cerebral blood flow measurement and computed tomography cisternography

    International Nuclear Information System (INIS)

    Chang, Chia-Cheng; Kuwana, Nobumasa; Ito, Susumu; Ikegami, Tadashi

    1999-01-01

    Measurement of cerebral blood flow (CBF) and computed tomography (CT) cisternography were performed in 37 patients with a tentative diagnosis of normal pressure hydrocephalus (NPH) to predict their surgical outcome. The mean CBF of the whole brain was measured quantitatively by single photon emission computed tomography with technetium-99m-hexamethylpropylene amine oxime before surgery. The results of CT cisternography were classified into four patients: type I, no ventricular stasis at 24 hours; type II, no ventricular stasis with delayed clearance of cerebral blush; type III, persistent ventricular stasis with prominent cerebral blush; type IV, persistent ventricular stasis with diminished cerebral blush and/or asymmetrical filling of the sylvian fissures. The mean CBF was significantly lower than that of age-matched controls (p<0.005). Patients with a favorable outcome had a significantly higher mean CBF than patients with an unfavorable outcome (p<0.005). Patients with the type I pattern did not respond to shunting. Some patients with type II and III patterns responded to shunting but improvement was unsatisfactory. Patients with type IV pattern responded well to shunting, and those with a mean CBF of 35 ml/100 g/min or over achieved a favorable outcome. The combination of CBF measurement and CT cisternography can improve the prediction of surgical outcome in patients with suspected NPH. (author)

  7. Quantitative measurement of regional cerebral blood flow with I-123 IMP SPECT; A correction of the microsphere model by global extraction between artery and internal jugular vein

    Energy Technology Data Exchange (ETDEWEB)

    Takeshita, Gen; Toyama, Hiroshi; Nakane, Kaori; Maeda, Hisato; Katada, Kazuhiro; Takeuchi, Akira; Koga, Sukehiko (Fujita Health Univ., Toyoake, Aichi (Japan))

    1991-11-01

    Quantitative measurements of regional cerebral blood flow with N-isopropyl-(Iodine 123)p-iodoamphetamine (I-123 IMP) as a microsphere model were performed in forty cases. The regional cerebral blood flow values obtained with I-123 IMP were slightly underestimated compared with those of Xe-133 inhalation methods (y=0.90x-2.1, r=0.85, p<0.01). After correction by global extraction (87%) between the artery and internal jugular vein, which was measured in four patients by means of a catheter technique, the underestimation of the values obtained with I-123 IMP was improved (y=1.0x-2.4, r=0.85, p<0.01). Several problems in the accurate quantitative measurement of regional cerebral blood flow with I-123 IMP are discussed. (author).

  8. Differences in lateral hemispheric asymmetries of cerebral blood flow measured by SPECT in dementia of Alzheimer type

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Nahoko (Niigata Univ. (Japan). School of Medicine)

    1993-12-01

    We studied 21 right-handed patients clinically diagnosed as dementia of Alzheimer type (8 men, 13 women; aged 53-85, mean 71.1 years). The average duration of symptoms was 2.7 years. Dementia ranged from mild to moderately severe. None had clinical or laboratory evidence of cerebro-vascular disease (Hachinski ischemic scores for all patients were 4 or below). All received the Wechsler Adult Intelligence Scale (WAIS), Mini-mental State Test (MMS) and Western Aphasia Battery (WAB, First Japanese edition, 1986). Regional cerebral blood flow was evaluated by single photon emission CT (SPECT) with [sup 123]I-N-isopropyl-p-iodoamphetamine ([sup 123]I-IMP), using the Matsuda's quantitative method. The subjects were divided into three groups on the basis of right-left hemispheric asymmetry of cerebral blood flow (leftblood flow. Verbal IQ in patients with predominant hypoperfusion of left temporal and parietal lobe were significantly lower than in other groups, while performance IQ and WAB constructive scores were lower in those with right hemispheric hypoperfusion (p<0.05). We concluded that cerebral blood flow asymmetry detected by SPECT was related significantly to the deficit of language and constructive function in patients with dementia of Alzheimer type. (author).

  9. Direct Blood Flow Measurements in a Free RPE-Choroid Graft with Phase-Resolved Doppler OCT

    NARCIS (Netherlands)

    van Zeeburg, Elsbeth J. T.; Braaf, Boy; Cereda, Matteo G.; van Meurs, Jan C.; de Boer, Johannes F.

    Purpose: : We directly demonstrated the revascularization in a free retinal pigment epithelium (RPE)-choroid graft with direct blood flow detection by experimental phase-resolved Doppler optical coherence tomography (PRD-OCT). Methods: : Seven patients with age-related macular degeneration underwent

  10. Spinal cord blood flow measured by 14C-iodoantipyrine autoradiography during and after graded spinal cord compression in rats

    International Nuclear Information System (INIS)

    Holtz, A.; Nystroem, B.G.; Gerdin, B.

    1989-01-01

    The relations between degree of thoracic spinal cord compression causing myelographic block, reversible paraparesis, and extinction of the sensory evoked potential on one hand, and spinal cord blood flow on the other, were investigated. This was done in rats using the blocking weight-technique and 14 C-iodoantipyrine autoradiography. A load of 9 g caused myelographic block. Five minutes of compression with that load caused a reduction of spinal cord blood flow to about 25%, but 5 and 60 minutes after the compression spinal cord blood flow was restored to 60% of the pretrauma value. A load of 35 g for 5 minutes caused transient paraparesis. Recovery to about 30% was observed 5 and 60 minutes thereafter. During compression at a load of 55 g, which caused almost total extinction of sensory evoked potential and irreversible paraplegia, spinal cord blood flow under the load ceased. The results indicate that myelographic block occurs at a load which does not cause irreversible paraparesis and that a load which permits sensory evoked potential to be elicited results in potentially salvageable damage

  11. Quantitation of contact allergy in guinea pigs by measuring changes in skin blood flow and skin fold thickness

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Staberg, B

    1985-01-01

    Skin blood flow determined by laser Doppler flowmetry (LDF) and skin fold thickness (SFT) have been used to quantitate allergic contact dermatitis in the guinea pig maximization test (GPMT) using chlorocresol as the allergen. The closed patch test procedure itself influenced both LDF and SFT...

  12. Measurement of cerebral blood flow the blood sampling method using 99mTc-ECD. Simultaneous scintigram scanning of arterial blood samples and the brain with a gamma camera

    International Nuclear Information System (INIS)

    Hachiya, Takenori; Inugami, Atsushi; Iida, Hidehiro; Mizuta, Yoshihiko; Kawakami, Takeshi; Inoue, Minoru

    1999-01-01

    To measure regional cerebral blood flow (rCBF) by blood sampling using 99m Tc-ECD we devised a method of measuring the radioactive concentration in arterial blood sample with a gamma camera. In this method the head and a blood sample are placed within the same visual field to record the SPECT data of both specimens simultaneously. The results of an evaluation of the counting rate performance, applying the 30 hours decaying method using 99m Tc solution showed that this method is not comparable to the well-type scintillation counter and in clinical cases the active concentration in arterial blood sample remained well within the dynamic range. In addition, examination of the influence of scattered radiation from the brain by the dilution method showed that it was negligible at a distance of more than 7.5 cm between the brain and the arterial blood sample. In the present study we placed a head-shaped phantom next to the sample. The results of the examinations suggested that this method is suitable for clinical application, and because it does not require a well-type scintillation counter, it is expected to find wide application. (author)

  13. Age-matched normal values and topographic maps for regional cerebral blood flow measurements by Xe-133 inhalation

    International Nuclear Information System (INIS)

    Matsuda, H.; Maeda, T.; Yamada, M.; Gui, L.X.; Tonami, N.; Hisada, K.

    1984-01-01

    The relationship between normal aging and regional cerebral blood flow (rCBF) computed as initial slope index (ISI) by Fourier method was investigated in 105 right-handed healthy volunteers (132 measurements) by Xe-133 inhalation method, and age-matched normal values were calculated. Mean brain ISI values showed significant negative correlation with advancing age (r . 0.70, p less than 0.001), and the regression line and its 95% confidence interval was Y . -0.32 (X - 19) + 63.5 +/- 11.2 (19 less than or equal to X less than or equal to 80). Regional ISI values also showed significant negative correlations for the entire brain (p less than 0.001). The regional reductions of ISI values with advancing age were significantly greater in the regional distribution of the middle cerebral arteries bilaterally, compared with regions in the distribution of the other arteries (p less than 0.05). Therefore, measured rCBF values for patients must be compared to age-matched normal values for mean hemispheric and each region examined. Two kinds of topographic maps, brain map showing rCBF compared to age-matched normal values and showing hemispheric differences were made by dividing patient's values by the 95% confidence limits for age-matched normal values and displaying laterality index calculated as follows, respectively. (formula; see text) These maps were useful for evaluating significantly decreased or increased regions and regional hemispheric differences

  14. 11C-Iodoantipyrine for the measurement of regional cerebral blood flow by positron emission tomography. Validation studies

    Energy Technology Data Exchange (ETDEWEB)

    Ginsberg, M.D.; Lockwood, A.H.; Busto, R.; Finn, R.D.; Campbell, J.A.; Boothe, T.E.

    Positron emission tomography (PET) makes it possible to employ an in vivo autoradiographic paradigm to measure regional cerebral blood flow (rCBF) in man. In this study, we synthesized the positron-emitting radiopharmaceutical 11C-iodoantipyrine (11C-IAP) and validated its suitability as a CBF tracer. 11C ( T and one-half 20.4 min) was produced by the (p,alpha) nuclear reaction on 14N. 11C-methyl iodide was used to methylate 3-methyl-1-phenyl-2-pyrazolin-5-one to form 11C-antipyrine, which was iodinated. Radiochemical purity of the 11C-IAP product was 93-98% except as described below. rCBF was measured with 11C-IAP in nitrous oxide-anesthetized Wistar rats by the method of indicator fractionation, and values were compared with rCBF values measured with simultaneously administered commercially produced 14C-IAP. rCBF was studied over a range of arterial Pco2 values (31-58 mm Hg, mean 43.0 +/- 3.5). Mean rCBF data for the 2 tracers agreed to within 4.8% for cerebral hemispheral samples, 3.8% for cerebellum, and 5.3% for brainstem. Mean values (+/- SEM) for rCBF using 11C-IAP were 1.67 +/- 0.20 ml gm-1 min-1 for cerebral hemispheres; 1.32 +/- 0.17 for cerebellum; and 1.50 +/- 0.21 for brainstem. When chromatographic analysis revealed tracer impurity, rCBF, as measured with 11C-IAP, fell consistently below values obtained with 14C-IAP. The data indicate that 11C-IAP, when properly synthesized and submitted to batch-by-batch quality control, may be suitable for measuring rCBF in man by emission tomography.

  15. Simultaneous, quantitative measurement of local blood flow and glucose utilization in tissue samples in normal and injured feline brain.

    Science.gov (United States)

    DeWitt, D S; Yuan, X Q; Becker, D P; Hayes, R L

    1988-01-01

    Cerebral blood flow (CBF) and local cerebral glucose utilization (LCGU) were measured using radioactive microspheres and [14C]2-deoxyglucose, respectively, in 26 brain regions in control animals (n = 8) and in animals (n = 4) sustaining low-level experimental brain injury. Examination of the initial (resting) CBF measurement in the uninjured cats revealed two subgroups with significantly (p less than 0.01) different CBF levels. In uninjured cats with normal CBF levels (33.4 +/- 1.8 ml/100 g/min) there was a close linear relationship between CBF and LCGU (n = 0.71, p less than 0.01). In contrast, the remainder of the uninjured cats exhibited abnormally high levels of CBF (72.6 +/- 9.9 ml/100 g/min) and the absence of a close relationship between CBF and LCGU (r = 0.27). One hour following low-level (2.0 atm) fluid percussion brain injury, CBF was increased and LCGU was decreased, though not significantly. The relationship between CBF and LCGU remained intact (r = 0.66, p less than 0.01) in most brain regions. However, the relationship between CBF and LCGU in the hippocampus differed significantly from the relationship between the two parameters in the rest of the brain. Thus, the use of the radioactive microsphere method for CBF measurements allows multiple measurements of CBF and permits the assessment of the status of the cerebral vasculature prior to experimental manipulations such as traumatic brain injury. In view of our current findings of an abnormal relationship between CBF and LCGU in cats with high resting CBF levels, this is an important advantage. In addition, the combination of the microsphere and 2-DG techniques within the same tissue samples allows for the investigation of the effects of traumatic injury on the important relationship between CBF and LCGU.

  16. Abdominal aorta: characterisation of blood flow and measurement of its regional distribution by cine magnetic resonance phase-shift velocity mapping

    Energy Technology Data Exchange (ETDEWEB)

    Amanuma, M. [Dept. of Radiology, Saitama Medical School (Japan); Mohiaddin, R.H. [Magnetic Resonance Unit, Royal Brompton Hospital, London (United Kingdom); Hasegawa, M. [Dept. of Radiology, Saitama Medical School (Japan); Heshiki, A. [Dept. of Radiology, Saitama Medical School (Japan); Longmore, D.B. [Magnetic Resonance Unit, Royal Brompton Hospital, London (United Kingdom)

    1992-12-01

    Magnetic resonance phase-shift-induced velocity mapping is a powerful technique for measuring in vivo blood velocity and flow non-invasively. Using this method we examined dimensions, distensibility, blood flow and its regional distribution in the abdominal aorta in 10 normal volunteers. Data were acquired at three levels of the descending aorta. Thirty percent reduction in diastolic cross sectional area was observed in the caudal direction between these levels. Total blood flow (ml/min) in the abdominal aorta at the three sites was 4094{+-}1600, 2339{+-}910 and 1602{+-}549 respectively. Flows in the coeliac trunk, superior mesenteric artery and renal arteries were also calculated. The net flow in the abdominal aorta above the coeliac trunk was persistently forward, while there was considerable backflow (13% of total instantaneous flow) below the renal arteries during early diastole. Magnetic resonance imaging is a non-invasive technique for quantitative assessment of blood flow in the abdominal aorta and its main branches. (orig.)

  17. Effect of Post-Reconstruction Gaussian Filtering on Image Quality and Myocardial Blood Flow Measurement with N-13 Ammonia PET

    Directory of Open Access Journals (Sweden)

    Hyeon Sik Kim

    2014-10-01

    Full Text Available Objective(s: In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF measurement by dynamic N-13 ammonia positron emission tomography (PET, we compared various reconstruction and filtering methods with image characteristics. Methods: Dynamic PET images of three patients with coronary artery disease (male-female ratio of 2:1; age: 57, 53, and 76 years were reconstructed, using filtered back projection (FBP and ordered subset expectation maximization (OSEM methods. OSEM reconstruction consisted of OSEM_2I, OSEM_4I, and OSEM_6I with 2, 4, and 6 iterations, respectively. The images, reconstructed and filtered by Gaussian filters of 5, 10, and 15 mm, were obtained, as well as non-filtered images. Visual analysis of image quality (IQ was performed using a 3-grade scoring system by 2 independent readers, blinded to the reconstruction and filtering methods of stress images. Then, signal-to-noise ratio (SNR was calculated by noise and contrast recovery (CR. Stress and rest MBF and coronary flow reserve (CFR were obtained for each method. IQ scores, stress and rest MBF, and CFR were compared between the methods, using Chi-square and Kruskal-Wallis tests. Results: In the visual analysis, IQ was significantly higher by 10 mm Gaussian filtering, compared to other sizes of filter (PP=0.923 and 0.855 for readers 1 and 2, respectively. SNR was significantly higher in 10 mm Gaussian filter. There was a significant difference in stress and rest MBF between several vascular territories. However CFR was not significantly different according to various filtering methods. Conclusion: Post-reconstruction Gaussian filtering with a filter size of 10 mm significantly enhances the IQ of N-13 ammonia PET-CT, without changing the results of CFR calculation. .

  18. Effect of Post-Reconstruction Gaussian Filtering on Image Quality and Myocardial Blood Flow Measurement with N-13 Ammonia PET

    International Nuclear Information System (INIS)

    Kim, Hyeon Sik; Cho, Sang-Geon; Kim, Ju Han; Kwon, Seong Young; Lee, Byeong-il; Bom, Hee-Seung

    2014-01-01

    In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF) measurement by dynamic N-13 ammonia positron emission tomography (PET), we compared various reconstruction and filtering methods with image characteristics. Dynamic PET images of three patients with coronary artery disease (male-female ratio of 2:1; age: 57, 53, and 76 years) were reconstructed, using filtered back projection (FBP) and ordered subset expectation maximization (OSEM) methods. OSEM reconstruction consisted of OSEM-2I, OSEM-4I, and OSEM-6I with 2, 4, and 6 iterations, respectively. The images, reconstructed and filtered by Gaussian filters of 5, 10, and 15 mm, were obtained, as well as non-filtered images. Visual analysis of image quality (IQ) was performed using a 3-grade scoring system by 2 independent readers, blinded to the reconstruction and filtering methods of stress images. Then, signal-to-noise ratio (SNR) was calculated by noise and contrast recovery (CR). Stress and rest MBF and coronary flow reserve (CFR) were obtained for each method. IQ scores, stress and rest MBF, and CFR were compared between the methods, using Chi-square and Kruskal-Wallis tests. In the visual analysis, IQ was significantly higher by 10 mm Gaussian filtering, compared to other sizes of filter (P<0.001 for both readers). However, no significant difference of IQ was found between FBP and various numbers of iteration in OSEM (P=0.923 and 0.855 for readers 1 and 2, respectively). SNR was significantly higher in 10 mm Gaussian filter. There was a significant difference in stress and rest MBF between several vascular territories. However CFR was not significantly different according to various filtering methods. Post-reconstruction Gaussian filtering with a filter size of 10 mm significantly enhances the IQ of N-13 ammonia PET-CT, without changing the results of CFR calculation

  19. Review: does measurement of regional cerebral blood flow reflect synaptic activity? Implications for PET and fMRI.

    Science.gov (United States)

    Jueptner, M; Weiller, C

    1995-06-01

    The energy metabolism of the adult human brain almost completely depends on glucose. The functional coupling of regional cerebral blood flow and local cerebral glucose metabolism has been established in a wide range of experiments using autoradiographic techniques in rats, cats, and monkeys as well as double-tracer techniques in humans. Glucose utilization in turn reflects neuronal activity and more specifically synaptic, mainly presynaptic, activity. The majority of glucose is needed for the maintenance of membrane potentials and restoration of ion gradients. PET as well as fMRI may be used to study changes in blood flow or flow-related phenomena in human subjects in vivo. Both techniques monitor changes of synaptic activity in a population of cells. These changes may be due to excitation or inhibition. More than 85% of cerebral glucose is used by neurons (mainly presynaptic axon terminals), while the remainder may at least partly account for metabolic processes in glial cells. Monitoring of regional cerebral blood flow with PET or fMRI thus mainly reflects neuronal and more specifically (pre-) synaptic activity.

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  1. Cerebral blood flow and glucose metabolism measured with positron emission tomography are decreased in human type 1 diabetes.

    Science.gov (United States)

    van Golen, Larissa W; Huisman, Marc C; Ijzerman, Richard G; Hoetjes, Nikie J; Schwarte, Lothar A; Lammertsma, Adriaan A; Diamant, Michaela

    2013-08-01

    Subclinical systemic microvascular dysfunction exists in asymptomatic patients with type 1 diabetes. We hypothesized that microangiopathy, resulting from long-standing systemic hyperglycemia and hyperinsulinemia, may be generalized to the brain, resulting in changes in cerebral blood flow (CBF) and metabolism in these patients. We performed dynamic [(15)O]H2O and [(18)F]-fluoro-2-deoxy-d-glucose brain positron emission tomography scans to measure CBF and cerebral glucose metabolism (CMRglu), respectively, in 30 type 1 diabetic patients and 12 age-matched healthy controls after an overnight fast. Regions of interest were automatically delineated on coregistered magnetic resonance images and full kinetic analysis was performed. Plasma glucose and insulin levels were higher in patients versus controls. Total gray matter CBF was 9%, whereas CMRglu was 21% lower in type 1 diabetic subjects versus control subjects. We conclude that at real-life fasting glucose and insulin levels, type 1 diabetes is associated with decreased resting cerebral glucose metabolism, which is only partially explained by the decreased CBF. These findings suggest that mechanisms other than generalized microangiopathy account for the altered CMRglu observed in well-controlled type 1 diabetes.

  2. Reduction in mean cerebral blood flow measurements using {sup 99m}Tc-ECD-SPECT during normal aging

    Energy Technology Data Exchange (ETDEWEB)

    Kawahata, Nobuya; Daitoh, Nobuyuki; Shirai, Fumie; Hara, Shigeru [Narita Memorial Hospital, Toyohashi, Aichi (Japan)

    1997-10-01

    Mean cerebral blood flow (mCBF) was measured by SPECT using the {sup 99m}Tc-ECD-Patlak-Plot method in a selected group of 61 normal non-hospitalized subjects aged 51 to 91 years. The mCBF values showed 48.4{+-}4.7 ml/100 g/min in aged 50-59 years group, 49.9{+-}5.9 ml/100 g/min in aged 60-69 years group, 46.4 {+-}6.5 ml/100 g/min in aged 70-79 group, 38.0{+-}3.7 ml/100 g/min in aged 80-89 years group, 38.9 ml/100 g/min in aged 90-99 years group. There was a statistically significant reduction of mCBF with advancing age (R=-0.41; p=0.001). Women have significantly higher mCBF values than men up to aged 70 years group. In this study, there was no significant laterality in the mCBF between right and left hemispheres in all decade groups. The history of hypertension, alcohol consumption, and cigarette smoking failed to show significant difference in the mCBF values. The present study shows that normal aging is associated with mCBF reduction. (author)

  3. The measurement of regional cerebral blood flow during the complex cognitive task of meditation: a preliminary SPECT study.

    Science.gov (United States)

    Newberg, A; Alavi, A; Baime, M; Pourdehnad, M; Santanna, J; d'Aquili, E

    2001-04-10

    This study measured changes in regional cerebral blood flow (rCBF) during the complex cognitive task of meditation using single photon emission computed tomography. Eight experienced Tibetan Buddhist meditators were injected at baseline with 7 mCi HMPAO and scanned 20 min later for 45 min. The subjects then meditated for 1 h at which time they were injected with 25 mCi HMPAO and scanned 20 min later for 30 min. Values were obtained for regions of interest in major brain structures and normalized to whole brain activity. The percentage change between meditation and baseline was compared. Correlations between structures were also determined. Significantly increased rCBF (P<0.05) was observed in the cingulate gyrus, inferior and orbital frontal cortex, dorsolateral prefrontal cortex (DLPFC), and thalamus. The change in rCBF in the left DLPFC correlated negatively (P<0.05) with that in the left superior parietal lobe. Increased frontal rCBF may reflect focused concentration and thalamic increases overall increased cortical activity during meditation. The correlation between the DLPFC and the superior parietal lobe may reflect an altered sense of space experienced during meditation. These results suggest a complex rCBF pattern during the task of meditation.

  4. Comparative study of regional cerebral blood flow values measured by IMP SPECT, 133Xe SPECT and Xe CT

    International Nuclear Information System (INIS)

    Matsuda, Masayuki; Lee, Hidehiko; Kuribayashi, Kousuke; Handa, Jyoji

    1996-01-01

    We measured the regional cerebral blood flow (rCBF) by N-isopropyl-p-[ 123 I] iodoamphetamine (IMP) SPECT using the recently proposed simplified method, and compared the values obtained with those determined by 133 Xe SPECT and Xe CT. A total of 10 patients with cerebrovascular disease was studied. In the region of the anterior cerebral artery of the non-lesion side, significantly lower values were obtained by Xe CT than by 133 Xe SPECT, whereas in the area of the middle cerebral artery, IMP SPECT recorded significantly higher values than the other two methods. In the territory of the posterior cerebral artery, IMP SPECT also recorded significantly higher values than the other methods, with the differences reaching 9. 3 ml/100g/min from 133 Xe SPECT and 12 ml/100g/min from Xe CT measurements. Similar results were seen with basal ganglia. When the region of interest (ROI) was placed on the whole hemisphere, there were no significant differences among the three methods, but the rCBF values varied from 39.2 ml/100g/min by 133 Xe SPECT, 36.1 ml/100g/min by Xe CT, to 32.8 ml/100g/min by IMP SPECT. The difference in rCBF values between the non-lesion and the lesion side was smaller by the 133 Xe SPECT modality and larger in the IMP SPECT method. It is evident from our results that there is a rather large difference, reaching statistical significance, among the rCBF values measured by the three methods, even in the hemisphere of the non-lesion side. Many factors, including the character of the tracer, sensitivity of the method, spatial resolution, slice thickness, and the size and location of the ROI depicted by free hand, are likely to be responsible for the observed discrepancies regarding numerical rCBF data. (author)

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

    DEFF Research Database (Denmark)

    Lubberink, Mark; Ebrahimi, M; Harms, Hans

    Aim: Motion-induced PET-CT misalignment artifacts are common in myocardial blood flow (MBF) measurements with 82Rb and 13N-ammonia. For 15O-water, MBF is based on the clearance rate rather than uptake of the tracer. The clearance rate is determined by the shape of the time-activity curve, not its...

  6. Cerebral blood-flow tomography

    DEFF Research Database (Denmark)

    Lassen, N A; Henriksen, L; Holm, S

    1983-01-01

    Tomographic maps of local cerebral blood flow (CBF) were obtained with xenon-133 and with isopropyl-amphetamine-iodine-123 (IMP) in 11 subjects: one normal, two tumor cases, and eight cerebrovascular cases. A highly sensitive four-face, rapidly rotating, single-photon emission tomograph was used....

  7. No effect of 85 mT permanent magnets on laser-Doppler measured blood flow response to inspiratory gasps.

    Science.gov (United States)

    Mayrovitz, Harvey N; Groseclose, Edye E; King, David

    2005-05-01

    Although no effects of permanent magnets on resting skin blood flow (SBF) in humans have yet been demonstrated, the possibility that magnet related effects might modify dynamic SBF changes has not been previously studied. We hypothesized that magnets may alter local neurovascular mechanisms to cause changes in normal SBF vasoactive responses. To test this, we studied the effects of a magnet on SBF reductions induced by sympathetic reflexes associated with deep inspirations. SBF was continuously monitored by a dual channel laser-Doppler flowmeter with probes on the middle finger dorsum of both hands of 24 healthy subjects. In the first of two successive intervals, each of the fingers rested on sham ceramic magnets (control interval). Subsequently, one finger rested on an active magnet and the other finger on a sham (experimental interval). Skin temperatures were also measured. The magnet was a 37 mm diameter x 14 mm thick ceramic magnet with a surface field strength of 85 mT measured in the geometrical center of the magnet. Field strength at the finger dorsum, 13 mm above magnet, was 31.5 mT. During each interval, three deep breaths were used to elicit SBF reductions. Responses were calculated as the percent reduction in SBF from its prior 20 s average. Breaths in each interval were spaced 3 min apart to permit full recovery between responses. The experimental interval started after an active magnet was in place for 20 min. Results showed no significant difference in either vasoconstrictive responses or skin temperature due to the magnet. We conclude that magnets of the type, strength and duration used, have no significant effect on vasoconstrictive processes associated with this sympathetic reflex in this group of healthy subjects. Copyright 2005 Wiley-Liss, Inc.

  8. Error analysis of tumor blood flow measurement using dynamic contrast-enhanced data and model-independent deconvolution analysis

    International Nuclear Information System (INIS)

    Murase, Kenya; Miyazaki, Shohei

    2007-01-01

    We performed error analysis of tumor blood flow (TBF) measurement using dynamic contrast-enhanced data and model-independent deconvolution analysis, based on computer simulations. For analysis, we generated a time-dependent concentration of the contrast agent in the volume of interest (VOI) from the arterial input function (AIF) consisting of gamma-variate functions using an adiabatic approximation to the tissue homogeneity model under various plasma flow (F p ), mean capillary transit time (T c ), permeability-surface area product (PS) and signal-to-noise ratio (SNR) values. Deconvolution analyses based on truncated singular value decomposition with a fixed threshold value (TSVD-F), with an adaptive threshold value (TSVD-A) and with the threshold value determined by generalized cross validation (TSVD-G) were used to estimate F p values from the simulated concentration-time curves in the VOI and AIF. First, we investigated the relationship between the optimal threshold value and SNR in TSVD-F, and then derived the equation describing the relationship between the threshold value and SNR for TSVD-A. Second, we investigated the dependences of the estimated F p values on T c , PS, the total duration for data acquisition and the shape of AIF. Although TSVD-F with a threshold value of 0.025, TSVD-A with the threshold value determined by the equation derived in this study and TSVD-G could estimate the F p values in a similar manner, the standard deviation of the estimates was the smallest and largest for TSVD-A and TSVD-G, respectively. PS did not largely affect the estimates, while T c did in all methods. Increasing the total duration significantly improved the variations in the estimates in all methods. TSVD-G was most sensitive to the shape of AIF, especially when the total duration was short. In conclusion, this study will be useful for understanding the reliability and limitation of model-independent deconvolution analysis when applied to TBF measurement using an

  9. Validation of the 133Xe inhalation method for measuring brain stem and cerebellar blood flow in human subjects and the baboon

    International Nuclear Information System (INIS)

    Sakai, F.; Meyer, J. St.; Yamaguchi, F.; Yamamoto, M.; Shaw, T.; Juge, O.

    1979-01-01

    Regional cerebral blood flow (rCBF) measurements recorded by probes placed over the posterior fossa after 133 Xe inhalation have been validated here in. After inhalation, 133 Xe gas is distributed via arterial blood of both carotid an vertebrobasilar systems, so that it should be possible to measure rCBF of the brain stem and cerebellum if appropriate collimation, probe placement and selection of activity are employed. Detectors placed over the suboccipital regions may be subject to distortion by radioactivity derived from extracerebral sources so that the following questions were asked: 1) What is the counting geometry for each probe looking at this area 2) What is the extent of contamination from surrounding tissues 3) Are the flow values reproducible and in accordance with values obtained by other techniques 4) Are the flow values able to show predictable changes under physiological and pathological conditions Animal and human experiments designed to answer these questions are reported. (Auth.)

  10. Myocardial Blood Flow and Flow Reserve in Proximal and Mid-to-Distal Lesions of Left Anterior Descending Artery Measured By N-13 Ammonia PET/CT

    International Nuclear Information System (INIS)

    Cho, Sanggeon; Kim, Ju Han; Cho, Jae Young; Kim, Hyeon Sik; Bom, Heeseung

    2013-01-01

    The purpose of this study is to compare the myocardial blood flow (MBF) and flow reserve (MFR) between proximal and mid-to-distal lesions of the left anterior descending artery (pLAD and mdLAD, respectively) using N-13 ammonia positron emission tomography/computed tomography (PET/CT). Subjects were 11 patients (six men and five women, mean age 64.5 years) with known coronary artery disease (CAD) involving LAD studied by N-13 ammonia PET/CT. They were divided into two groups by the location of stenotic lesions, i.e. pLAD versus mdLAD. Global and regional MBF and MFR were measured and compared. Characteristics of perfusion defects including the number of involved segments, basal area involvement, location, size, and shape were also compared between the two groups. The regional MFR in mid-anterior segment was significantly lower in pLAD group (1.80±0.35 vs 2.76±1.13 for pLAD and mdLAD groups, respectively, p=0.034), while global MFR was not different (2.10±1.10 vs 2.34±0.84). Both stress and rest MBF in LAD territories were not different in both groups. The size of the perfusion defects were significantly larger in pLAD group (44.0±11.5 % vs 21-1±15.8 %, p=0.041). Other characteristics such as location, basal area involvement, and shape were not significantly different between two groups. Conclusions The proximal lesion makes lower MFR in the mid-anterior segment and larger perfusion defect in the LAD territory but comparable MBF compared with mdLAD lesion

  11. Effects of antipsoriatic treatment on cutaneous blood flow in psoriasis measured by 133Xe washout method and laser Doppler velocimetry

    International Nuclear Information System (INIS)

    Klemp, P.; Staberg, B.

    1985-01-01

    In 8 patients with psoriasis vulgaris, the cutaneous blood flow (CBF) was measured simultaneously in both involved and uninvolved psoriatic skin before (i.e., on the first day of hospitalization) and on the 3rd, 7th, 14th, and 28th days of treatment with tar. The 133 Xe washout method was used after epicutaneous labeling and compared to the laser Doppler velocimetry (LDV) technique. Control experiments were performed in 10 normal individuals. Before treatment the mean CBF in involved psoriatic skin was 62.6 +/- 18.7 SD ml X (100 g X min)-1, which is significantly higher than CBF of uninvolved skin in psoriatic patients, 9.5 +/- 4.0 SD ml X (100 g X min)-1, (p less than 0.01) and is 13.6 times higher than CBF in the normal individuals (p less than 0.01). Fifty hours following onset of treatment (i.e., after only 2 applications of tar), mean CBF of the involved psoriatic skin had decreased significantly to 35.0 +/- 13.9 SD ml X (100 g X min)-1, (p less than 0.01), which was not statistically different from the CBF on the 7th day. During the following weeks, the CBF in involved psoriatic skin decreased at a more moderate rate than that observed during the first week and was 15.0 +/- 6.1 SD ml X (100 g X min)-1 on the 28th day. This value is not significantly different from the CBF of uninvolved skin in these patients. At the end of treatment, the CBF of the uninvolved skin had decreased significantly (p less than 0.05) in all the patients to values similar to those observed in the skin of normal individuals. A parallel decline was observed in a clinical psoriatic score index; however, it is not known whether the observed decrease in CBF was preceded or succeeded by the clinical improvement

  12. Effects of vasoactive stimuli on blood flow to choroid plexus

    Energy Technology Data Exchange (ETDEWEB)

    Faraci, F.M.; Mayhan, W.G.; Williams, J.K.; Heistad, D.D. (Univ. of Iowa College of Medicine, Iowa City (USA))

    1988-02-01

    The goal of this study was to examine effects of vasoactive stimuli on blood flow to choroid plexus. The authors used microspheres to measure blood flow to choroid plexus and cerebrum in anesthetized dogs and rabbits. A critical assumption of the microsphere method is that microspheres do not pass through arteriovenous shunts. Blood flow values obtained with simultaneous injection of 15- and 50-{mu}m microspheres were similar, which suggest that shunting of 15-{mu}m microspheres was minimal. Blood flow to choroid plexus under control conditions was 287 {plus minus} 26 (means {plus minus} SE) ml {center dot} min{sup {minus}1} {center dot} 100 g{sup {minus}1} in dogs and 385 {plus minus} 73 ml {center dot} min{sup {minus}1} 100 g{sup {minus}1} in rabbits. Consecutive measurements under control conditions indicated that values for blood flow are reproducible. Adenosine did not alter blood flow to cerebrum but increased blood flow to choroid plexus two- to threefold in dogs and rabbits. Norepinephrine and phenylephrine did not affect blood flow to choroid plexus and cerebrum but decreased blood flow to choroid plexus by {approx} 50%. The authors suggest that (1) the microsphere method provides reproducible valid measurements of blood flow to the choroid plexus in dogs and rabbits and (2) vasoactive stimuli may have profoundly different effects on blood flow to choroid plexus and cerebrum.

  13. Clinical study of cerebral blood flow in bilateral chronic subdural hematoma measured by 99mTc-HMPAO SPECT

    International Nuclear Information System (INIS)

    Okuyama, Tohru; Saito, Koji; Fukuyama, Kohichi; Yamamoto, Kouki; Morimoto, Mamoru; Aburano, Tamio

    2000-01-01

    Cerebral blood flow (CBF) in 34 patients with bilateral chronic subdural hematoma was measured by 99m Tc-HMPAO SPECT before operation. The regional CBF was measured in 26 regions of the 10 cortical regions, putamen, thalamus and cerebellar hemisphere on both sides. According to the thickness of subdural hematoma, the thicker hematoma side was measured and examined as the thick hematoma side, and the other side as the thin hematoma side. Thirty four cases with bilateral chronic subdural hematoma were classified into four groups on the basis of clinical symptoms :13 cases with headache (headache group), 10 cases with hemiparesis (hemiparesis group), 5 cases with tetraparesis (tetraparesis group) and 6 cases with consciousness disturbance or dementia (consciousness disturbance group), and into two groups according to the degree of midline brain shift on MRI: 14 cases of non-shifted group and 20 cases of shifted group. The average CBF of 34 patients in each region indicated a regional CBF reduction in the frontal, parietal and occipital cortices on the thin hematoma side, and in the putamen on the thick hematoma side. In the headache group, the regional CBF reduction on the thin hematoma side was found in the frontal, parietal and occipital cortices compared with the corresponding regions on the thick hematoma side, and in thalamus on the thick hematoma side. In the hemiparesis and tetraparesis groups, there was no statistically significant CBF reduction between the thick and thin hematoma sides. In the consciousness disturbance group, the CBF reduction in whole brain was remarkably significant. By the degree of the midline brain shift, the CBF reductions between the thick and thin hematoma sides were observed. Namely, in the shifted group, the CBF reductions were noted in the frontal, parietal and occipital cortices in the thin hematoma side, and in the putamen in the thick hematoma side. We concluded that the CBF reduction of bilateral chronic subdural hematoma was

  14. Regional cerebral blood flow in aphasia

    DEFF Research Database (Denmark)

    Soh, K; Larsen, B; Skinhøj, E

    1978-01-01

    Regional cerebral blood flow (rCBF) was studied in 13 aphasic patients with left hemisphere lesions, using the intracarotid xenon 133 injection method and a 254-detector gamma camera system. The rCBF was measured during rest and during various function tests, including a simple speech test...

  15. Cerebral blood flow in acute mountain sickness

    DEFF Research Database (Denmark)

    Jensen, J B; Wright, Anne; Lassen, N A

    1990-01-01

    Changes in cerebral blood flow (CBF) were measured using the radioactive xenon technique and were related to the development of acute mountain sickness (AMS). In 12 subjects, ascending from 150 to 3,475 m, CBF was 24% increased at 24 h [45.1 to 55.9 initial slope index (ISI) units] and 4% increased...

  16. The effect of sympathectomy on bone blood flow in man

    International Nuclear Information System (INIS)

    Lahtinen, T.; Alhava, E.M.; Hyoedynmaa, S.; Hendolin, H.; Oksala, I.

    1982-01-01

    The effect of lumbar sympathectomy on bone blood flow was measured in seven patients with a Xe-133 washout method. On the third postoperative day there was a significant increase of blood flow in the proximal femur and a slight increase in the proximal tibia. Two months after the operation blood flow in the proximal part of the femur was no more significantly increased but in the proximal tibia there was a significant increase. The study suggests that the positive effect of sympathectomy on bone blood flow may be of value in cases where the increase of blood flow to peripheral bones is required

  17. The effect of isometric exercise of the hand on the synovial blood flow in patients with rheumatoid arthritis measured by color Doppler ultrasound

    DEFF Research Database (Denmark)

    Ellegaard, Karen; Torp-Pedersen, Søren; Lund, Hans

    2013-01-01

    made it possible to investigate the direct effect on blood supply in the synovium after training. In this case-control study, 24 patients with RA with USD activity in the wrist joint participated. The USD activity was measured by the color fraction (CF) (CF = colored pixels/total number of pixels......In 90% of patients with rheumatoid arthritis (RA), the joints of the hand are affected. Studies of grip strength training have not indicated a negative effect on disease activity after training. Introduction of ultrasound Doppler (USD) to measure increased blood flow induced by inflammation has...

  18. Blood flow in healed and inflamed periodontal tissues of dogs

    Energy Technology Data Exchange (ETDEWEB)

    Hock, J.M.; Kim, S.

    1987-01-01

    The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p<0.05) lower in non-inflamed healed gingiva (32.1 +- 2.7 ml/min/100 g) than in inflamed gingiva (46.1 +- 5.3 ml/min/100 g). No differences in the blood flow of the alveolar bone underlying inflamed or non-inflamed gingiva were present. In the second experiment, the right mandibular teeth of 5 dogs were treated to resolve periodontitis while teeth in the other quadrants were ligated for 4, 10 or 12 wk. The duration of ligation did not alter blood flow. Gingival blood flow around ligated maxillary and mandibular teeth was comparable and approximately 54% higher than around non-ligated teeth (p<0.03). The difference in blood flow between gingiva with G.I.>1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow.

  19. Subcutaneous blood flow during insulin-induced hypoglycaemia

    DEFF Research Database (Denmark)

    Hilsted, J; Madsbad, S; Sestoft, L

    1982-01-01

    Subcutaneous blood flow was measured preceding insulin-induced hypoglycaemia, at the onset of hypoglycaemic symptoms and 2 h later in juvenile diabetics with and without autonomic neuropathy and in normal males. In all groups subcutaneous blood flow decreased at the onset of hypoglycaemic symptoms...... compared with pre-hypoglycaemic flow. Two hours after onset of hypoglycaemic symptoms, subcutaneous blood flow was still significantly decreased compared with pre-hypoglycaemic flow. In normal subjects local nerve blockade had no effect on blood flow changes during hypoglycaemia, whereas local alpha...

  20. A simple method for regional cerebral blood flow measurement by one-point arterial blood sampling and 123I-IMP microsphere model (part 2). A study of time correction of one-point blood sample count

    International Nuclear Information System (INIS)

    Masuda, Yasuhiko; Makino, Kenichi; Gotoh, Satoshi

    1999-01-01

    In our previous paper regarding determination of the regional cerebral blood flow (rCBF) using the 123 I-IMP microsphere model, we reported that the accuracy of determination of the integrated value of the input function from one-point arterial blood sampling can be increased by performing correction using the 5 min: 29 min ratio for the whole-brain count. However, failure to carry out the arterial blood collection at exactly 5 minutes after 123 I-IMP injection causes errors with this method, and there is thus a time limitation. We have now revised out method so that the one-point arterial blood sampling can be performed at any time during the interval between 5 minutes and 20 minutes after 123 I-IMP injection, with addition of a correction step for the sampling time. This revised method permits more accurate estimation of the integral of the input functions. This method was then applied to 174 experimental subjects: one-point blood samples collected at random times between 5 and 20 minutes, and the estimated values for the continuous arterial octanol extraction count (COC) were determined. The mean error rate between the COC and the actual measured continuous arterial octanol extraction count (OC) was 3.6%, and the standard deviation was 12.7%. Accordingly, in 70% of the cases, the rCBF was able to be estimated within an error rate of 13%, while estimation was possible in 95% of the cases within an error rate of 25%. This improved method is a simple technique for determination of the rCBF by 123 I-IMP microsphere model and one-point arterial blood sampling which no longer shows a time limitation and does not require any octanol extraction step. (author)

  1. Measurement of Diaphragmatic Blood Flow and Oxygen Consumption in the Dog by the Kety-Schmidt Technique

    Science.gov (United States)

    Rochester, Dudley F.

    1974-01-01

    To assess energy expenditure of the diaphragm directly, a method was devised for percutaneous catheterization of the left inferior phrenic vein in dogs. Necropsy studies, including retrograde injection of india ink and measurement of radioactivity in diaphragmatic muscle strips, suggested that the territory drained by the inferior phrenic vein was uniformly perfused, and that there were no major anastomoses between this bed and adjacent ones. Diaphragmatic blood flow (˙Q di) was calculated from the integrated diaphragmatic arteriovenous difference of 85Kr by the Kety-Schmidt technique. Diaphragmatic oxygen consumption (˙Vo2 di) was determined as the product of ˙Q di and the diaphragmatic arteriovenous oxygen content difference [(A-V)O2 di]. When lightly anesthetized dogs breathed quietly, ˙Q di was 22±SD 6 ml/min/100 g, (A-V)O2 di was 6.1±SD 2.5 ml/100 ml, and ˙VO2 di averaged 1.2±SD 0.3 ml/min/100 g. This represented 1.0±SD 0.2% of total body oxygen consumption. ˙VO2 di remained relatively constant during quiet breathing, whereas ˙Q di varied directly with cardiac output and reciprocally with (A-V)O2 di. The oxygen consumption of the noncontracting diaphragm was 60±SD 20% of the level measured during quiet breathing. The energy expended by the diaphragm to support simple hyperventilation was small. A 100% increase in minute ventilation, induced by inhalation of 5% CO2 in 21% or 14% O2, increased ˙Q di 13%, (A-V)O2 di 19%, and ˙VO2 di 40%. The diaphragm consumed 0.13±SD 0.09 ml O2 for each additional liter of ventilation. In four dogs, pneumonia appeared to increase ˙VO2 both by increasing minute ventilation and by increasing the energy cost per liter of ventilation. PMID:4825221

  2. Clinical study of cerebral blood flow in unilateral chronic subdural hematoma measured by 99mTc-HMPAO SPECT

    International Nuclear Information System (INIS)

    Okuyama, Tohru; Saito, Koji; Fukuyama, Kohichi; Yamamoto, Kouki; Morimoto, Mamoru; Aburano, Tamio

    2000-01-01

    Cerebral blood flow (CBF) measured by 99m Tc-HMPAO SPECT before operation was studied in 60 patients with unilateral chronic subdural hematoma. The regional CBF was measured in 26 regions of the fronto-occipital 10 cortices, putamen, thalamus and cerebellar hemisphere on both sides. Sixty cases with unilateral chronic subdural hematoma were classified into four groups on the basis of clinical symptoms: 17 cases with headache (headache group), 34 cases with hemiparesis (hemiparesis group) and 9 cases with consciousness disturbance or dementia (consciousness disturbance group), and into three groups on the basis of the degree of midline brain shift on MRI: 7 cases of mild shift group, 24 cases of moderate shift group and 29 cases of severe shift group. The average CBF in 60 patients in each region indicated that the regional CBF was reduced in frontal, occipital cortices and cerebellum on the non-hematoma side, and in putamen and thalamus on the hematoma side. In the headache group, the regional CBF reduction on the non-hematoma side was found in only frontal and occipital cortices compared with the corresponding regions on the hematoma side. In the hemiparesis group, the regional CBF was reduced in frontal and occipital cortices on the non-hematoma side and in putamen and thalamus on the hematoma side. The part of CBF reduction in both hemispheres was also noted in the hemiparesis group. In the consciousness disturbance group, the CBF reduction was markedly noted in whole brain. The CBF reductions in frontal and occipital cortices on the non-hematoma side and in putamen, thalamus and cerebellum on the hematoma side was not mutually related with the degree of midline brain shift. We concluded that the disturbance of CBF in chronic subdural hematoma was started from frontal and occipital cortices on the non-hematoma side observed in the headache group, and which was extended to putamen and thalamus on the hematoma side and a part of both hemispheres observed in the

  3. Blood flow in healed and inflamed periodontal tissues of dogs

    International Nuclear Information System (INIS)

    Hock, J.M.; Kim, S.

    1987-01-01

    The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p 1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow. (author)

  4. Regional cerebral blood flow in aphasia

    DEFF Research Database (Denmark)

    Soh, K; Larsen, B; Skinhøj, E

    1978-01-01

    Regional cerebral blood flow (rCBF) was studied in 13 aphasic patients with left hemisphere lesions, using the intracarotid xenon 133 injection method and a 254-detector gamma camera system. The rCBF was measured during rest and during various function tests, including a simple speech test...... whatsoever. This is probably related to the functional nature of the rCBF method: subnormal flow values and lack of the normal flow increase during function tests apparently may disclose functionally inactivated but structurally intact cortex....

  5. Coronary sinus flow measured by pulsed Doppler ultrasound is a powerful indicator of coronary blood supply- a pig heart in vitro study.

    Science.gov (United States)

    Zheng, Xiao-Zhi; Wu, Jing; Hua, Jie

    2016-06-01

    To evaluate the correlation between the coronary sinus flow and the infusion volume in the coronaries and assess the performance of coronary sinus flow in predicting coronary artery occlusion in an isolated pig heart. The coronary sinus flow was measured in 16 isolated pig hearts by pulsed Doppler ultrasound. The correlation between the coronary sinus flow and the infusion volume in different coronary artery was analyzed, and the performance of coronary sinus flow in predicting different coronary artery occlusion was deducted. There were no statistically significant differences between the coronary sinus flow and the infusion volume in different coronary artery (p>0.05). The correlations between the coronary sinus flow and the infusion volume in left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), LAD and LCX, and LAD, LCX and right coronary artery (RCA) were all higher than 0.85 (p85% sensitivity and specificity. Excepting RCA mild occlusion (80% sensitivity and specificity. Conclusions The coronary sinus flow measured by pulsed Doppler ultrasound can effectively and exactly reflect the infusion volume in coronaries, which is a powerful indicator of coronary blood supply.

  6. Subcutaneous blood flow in psoriasis

    International Nuclear Information System (INIS)

    Klemp, P.

    1985-01-01

    The simultaneously recorded disappearance rates of 133 xe from subcutaneous adipose tissue in the crus were studied in 10 patients with psoriasis vulgaris using atraumatic labeling of the tissue in lesional skin (LS) areas and symmetrical, nonlesional skin (NLS) areas. Control experiments were performed bilaterally in 10 younger, healthy subjects. The subcutaneous washout rate constant was significantly higher in LS, 0.79 +/- 0.05 min-1 x 10(2) compared to the washout rate constant of NLS, 0.56 +/- 0.07 min-1. 10(2), or the washout rate constant in the normal subjects, 0.46 +/- 0.17 min-1 x 10(2). The mean washout rate constant in NLS was 25% higher than the mean washout rate constant in the normal subjects. The difference was, however, not statistically significant. Differences in the washout rate constants might be due to abnormal subcutaneous tissue-to-blood partition (lambda) in the LS--and therefore not reflecting the real differences in the subcutaneous blood flow (SBF). The lambda for 133 Xe was therefore measured--using a double isotope washout method ( 133 Xe and [ 131 I]antipyrine)--in symmetrical sites of the lateral crus in LS and NLS of 10 patients with psoriasis vulgaris and in 10 legs of normal subjects. In LS the lambda was 4.52 +/- 1.67 ml/g, which was not statistically different from that of NLS, 5.25 +/- 2.19 ml/g, nor from that of normal subcutaneous tissue, 4.98 +/- 1.04 ml/g. Calculations of the SBF using the obtained lambda values gave a significantly higher SBF in LS, 3.57 +/- 0.23 ml/100 g/min, compared to SBF in the NLS, 2.94 +/- 0.37 ml/100 g/min. There was no statistically significant difference between SBF in NLS and SBF in the normal subjects. The increased SBF in LS of psoriatics might be a secondary phenomenon to an increased heat loss in the lesional skin

  7. Blood flow restriction and cuff width: effect on blood flow in the legs.

    Science.gov (United States)

    Mouser, J Grant; Dankel, Scott J; Mattocks, Kevin T; Jessee, Matthew B; Buckner, Samuel L; Abe, Takashi; Loenneke, Jeremy P

    2018-01-21

    Much of the literature examining blood flow restriction in the lower body uses cuffs of differing widths. It is currently unknown whether similar relative pressures using cuffs of differing widths elicit the same blood flow response. To examine the hemodynamic responses to relative pressures using two commonly used cuffs (10 and 12 cm). In a random order over two laboratory visits, one cuff was applied to the right proximal thigh of the participant (men = 17, women = 14), and arterial occlusion pressure (AOP) was measured. Ultrasound measures of blood flow, mean blood velocity, peak blood velocity and artery diameter were taken from the posterior tibial artery at rest and during the application of 10% increments of the AOP. There was no significant difference between the 10- and 12-cm cuff relating to blood flow (-0·501 ml min -1 , SD 7·9, P = 0·728), mean blood velocity (-0·168 cm s -1 , SD 1·7, P = 0·590), peak blood velocity (0·586 cm s -1 , SD 11·7, P = 0·783) or artery diameter (0·003 cm, SD 0·02, P = 0·476). There was a main effect of pressure for blood flow (Pflow stimulus during blood flow restriction at rest. © 2018 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  8. Measurement of cerebral blood flow by intravenous xenon-133 technique and a mobile system. Reproducibility using the Obrist model compared to total curve analysis

    DEFF Research Database (Denmark)

    Schroeder, T; Holstein, P; Lassen, N A

    1986-01-01

    was considerably more reproducible than CBF level. Using a single detector instead of five regional values averaged as the hemispheric flow increased standard deviation of CBF level by 10-20%, while the variation in asymmetry was doubled. In optimal measuring conditions the two models revealed no significant...... differences, but in low flow situations the artifact model yielded significantly more stable results. The present apparatus, equipped with 3-5 detectors covering each hemisphere, offers the opportunity of performing serial CBF measurements in situations not otherwise feasible.......The recent development of a mobile 10 detector unit, using i.v. Xenon-133 technique, has made it possible to perform repeated bedside measurements of cerebral blood flow (CBF). Test-retest studies were carried out in 38 atherosclerotic subjects, in order to evaluate the reproducibility of CBF level...

  9. Comprasion of ovarian stromal blood flow measured by color Doppler ultrasonography in polycystic ovary syndrome patients and healthy women with ultrasonographic evidence of polycystic.

    Science.gov (United States)

    Ozdemir, Ozhan; Sari, Mustafa Erkan; Kalkan, Dilek; Koc, Esra Meltem; Ozdemir, Seyda; Atalay, Cemal Resat

    2015-04-01

    To compare ovarian stromal artery blood flows measured by Doppler ultrasonography of polycystic ovary syndrome (PCOS) patients and healthy women with polycystic ovarian image in ultrasonography. Forty-two patients diagnosed with PCOS according to the criteria of 2003 Rotterdam Concencus Conferance on PCOS and 38 healthy volunteers with polycystic ovarian image in ultrasonography were included in the study. Ovarian volumes and ovarian stromal artery blood flows were measured by 3-dimensional (3-D) ultrasonography and Doppler ultrasonography in all patients. In patients with PCOS, ovarian stromal artery pulsatility index (PI) and resistivity index (RI) were found significantly different from healthy women with polycystic ovarian image in ultrasonography (p polycystic ovarian image only. We conclude that Doppler ultrasonography findings of PCOS patients might be helpful in understanding the clinical follow-up and etiology of the disease.

  10. Effect of sumatriptan on cerebral blood flow during migraine headache. Measurement by sequential SPECT used 99mTc-ECD background subtraction method

    International Nuclear Information System (INIS)

    Ueda, Takashi; Torihara, Yoshito; Tsuneyoshi, Noritaka; Ikeda, Yoshitomo

    2001-01-01

    The present study was designed to examine the effect of sumatriptan on regional cerebral blood flow (CBF) during migraine headache. Nine cases were examined by 99m Tc-ECD background subtraction method for the absolute value measurement of regional CBF before and after sumatriptan injection. rCBF except for occipital and perioccipital lobes, were increased 10-20% during migraine headache and significant decreases were observed by sumatriptan injection. Two cases of nine had transiently increased systemic blood pressure and cardiac pulse rate, however, all cases improved migraine headache after injection of sumatriptan. (author)

  11. CONTRIBUTION OF FRONTAL CEREBRAL BLOOD FLOW MEASURED BY 99mTc-BICISATE SPECT AND EXECUTIVE FUNCTION DEFICITS TO PREDICTING TREATMENT OUTCOME IN ALCOHOL-DEPENDENT PATIENTS

    OpenAIRE

    Noël, Xavier; Sferrazza, Rita; Van der Linden, Martial; Paternot, Jacques; Verhas, Michel; Hanak, Catherine; Pelc, Isidore; Verbanck, Paul

    2017-01-01

    — Aim: To determine whether inhibition and working memory deficits, and reduced regional cerebral blood flow (rCBF) (previously shown to be related), measured at the end of a detoxification programme, predict alcoholic relapse 2 months later. Methods: Twenty uncomplicated alcoholic inpatients were investigated at the end of detoxification, at least 7 days since the last dose of diazepam, and a mean of 18.8 days since the last drink. Their performance was assessed on the inhibition (Hayling) t...

  12. Testicular blood flow in varicocele

    International Nuclear Information System (INIS)

    Iwamoto, Teruaki; Hirokawa, Makoto.

    1986-01-01

    Radioisotopic scrotal angiography was applied for study of testicular blood flow of patients with varicocele. Following iv. bolus injection of 10 ∼ 20 mCi of Tc human serum albumine, Tc RBC or Tc pertechnetate, time activity curve of radioactivity at corresponding bilateral areas of scrotum was simultaneously generated and compared. Eighty-four patients with overt varicocele (grade 2 and 3) at left side only, were selected for the present study and eight healthy young volunteers were studied as a control group. Three patterns of time activity curves were recognized. They are as follows. Type 1, where radioactivity was accumulated quickly in left side and then decreased gradually. Bilateral time activity curves were asymmetrical. Type 2, where time activity curves rose gradually and to a higher level at the left side than at the right side. Type 3, where bilateral time activity curves increased gradually, and symmetrically. All of the control group showed the same pattern as Type 3. Of the 84 patients examined, 34 patients showed Type 1, including 7 with grade 2 and 27 with grade 3. Twenty-four patients showed Type 2. consisting of 12 with grade 2 and 12 with grade 3. Twenty-six patients showed Type 3, consisting of 14 with grade 2 and 12 with grade 3. We presumed the following about testicular blood flow in varicocele: Type 1 pattern shows retrograde blood flow from the renal vein to the internal spermatic vein, Type 2 pattern shows poor venous return through the internal spermatic vein and Type 3 pattern shows good venous return though the presence of dilatated pampiniform plexus. (author)

  13. Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

    DEFF Research Database (Denmark)

    Sindrup, J H; Kastrup, J; Christensen, H

    1991-01-01

    Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit...... were used for measurement of blood flow rates. An automatic portable blood pressure recorder and processor unit was used for measurement of systolic blood pressure, diastolic blood pressure, and heart rate every 15 min. The change from upright to supine position at the beginning of the night period...... was associated with a 30-40% increase in blood flow rate and a highly significant decrease in mean arterial blood pressure and heart rate (P less than 0.001 for all). Approximately 100 min after the subjects went to sleep an additional blood flow rate increment (mean 56%) and a simultaneous significant decrease...

  14. Simultaneous measurement of local cortical blood flow and tissue oxygen saturation by Near infra-red Laser Doppler flowmetry and remission spectroscopy in the pig brain.

    Science.gov (United States)

    Walter, B; Bauer, R; Krug, A; Derfuss, Th; Traichel, F; Sommer, N

    2002-01-01

    In the current study we evaluated the combined use of Near-infrared Laser-Doppler flowmetry (NiLDF) and Remission Spectroscopy (RS) for measurement of regional perfusion and oxygen saturation of the cerebral cortex. An epidural probe for combined measurements of NiLDF and RS was placed above the parietal or frontal cortex of nine anesthetized juvenile pigs. Cerebral perfusion pressure (CPP) was stepwise decreased by intracisternal infusion of artificial CSF at clamped arterial blood pressure (baseline, CPP50, CPP40, CPP30 mmHg, ischemia). Subsequent reperfusion was followed for 3 h. Regional cerebral blood flow (rCBF) was measured with colored microspheres (CMS) and compared with corresponding NiLDF values during CMS injection. Cerebral venous oxygen saturation was measured in blood samples withdrawn from the sagittal sinus and compared with simultaneous recordings of tissue oxygenation during blood withdrawal. Linear regression analysis resulted in a significant correlation (p measured with CMS and NiLDF (r = 0.92, n = 39). A significant correlation was also found for tissue oxygen saturation--as measured with RS--and cerebral venous oxygen saturation (r = 0.85, n = 67). Although the problem of spatial variability remains to be solved, the combined use of NiLDF and RS allows continuous and non-invasive monitoring of changes of key parameters of oxygen metabolism within the cerebral cortex.

  15. Measurement of blood flow in the superior sagittal sinus in healthy volunteers, and in patients with normal pressure hydrocephalus and idiopathic intracranial hypertension with phase-contrast cine MR imaging

    DEFF Research Database (Denmark)

    Gideon, P; Thomsen, C; Gjerris, F

    1996-01-01

    PURPOSE: To measure blood flow and velocity in the superior sagittal ++sinus. MATERIAL AND METHODS: MR velocity mapping was used to examine 14 healthy volunteers, 15 patients with normal pressure hydrocephalus (NPH), 3 patients with high pressure hydrocephalus (HPH), and 11 patients with idiopathic...... intracranial hypertension (IIH). RESULTS: Mean blood flow was 443 ml/min in healthy volunteers with a tendency towards reduced blood flow with increasing age. In NPH patients significantly lower superior sagittal sinus blood flow values were found, but this difference was no longer significant when patients...

  16. EFFECT OF INCREASED WHOLE-BLOOD VISCOSITY ON REGIONAL BLOOD FLOWS IN CHRONICALLY HYPOXEMIC LAMBS

    NARCIS (Netherlands)

    DALINGHAUS, M; KNOESTER, H; GRATAMA, JWC; VANDERMEER, J; ZIJLSTRA, WG; KUIPERS, JRG

    In chronic hypoxemia blood flow and oxygen supply to vital organs are maintained, but to nonvital organs they are decreased. We measured organ blood flows (microspheres) and whole blood viscosity in 10 chronically hypoxemic lambs, with an atrial septal defect and pulmonary stenosis, and in 8 control

  17. Measurement of skin blood-flow and water evaporation as a means of objectively assessing hot flushes after orchidectomy in patients with prostatic cancer.

    Science.gov (United States)

    Frödin, T; Alund, G; Varenhorst, E

    1985-01-01

    Hot flushes can occur after orchidectomy for carcinoma of the prostate and are sometimes greatly distressing for patients. Attacks are difficult to register because of their transient and unpredictable nature and have been the object of very little scientific investigation. In 13 postorchidectomy patients who reported hot flushes we recorded cutaneous blood-flow and sweating by use of a laser-Doppler flowmeter and an evaporimeter. A total of 23 attacks were recorded. The rate of evaporation increased by more than 60 g/m2/h in ten attacks, from 10 to 60 g/m2/h in five attacks, and by less than 10 g/m2/h in seven attacks. The cutaneous blood-flow increased synchronously with the increase in evaporation. The intensity of the attacks as experienced by the patients corresponded closely to recorded measurements.

  18. Regional blood flow studies with radioisotopes

    International Nuclear Information System (INIS)

    Holman, B.L.; McNiel, B.J.; Adelstein, S.J.

    1975-01-01

    The methodological approaches to blood flow analysis include (1) diffusible indicator methods, (2) clearance techniques and (3) nondiffusible indicator methods. In each case, accurate measurements of blood flow can be obtained by developing mathematical models which relate the time-dependent observation derived from following the fate of a radiotracer as a function of time to the physiological process itself. Application of these models to biological systems involves constraints and necessitates compromises which may affect the validity of the measurements. Nevertheless, when these techniques are carefully applied and adequately validated, they have provided critical physiological information about such organ systems as the brain and kidney and promise to provide diagnostic information in patients with suspected coronary and peripheral vascular disease

  19. Cerebral blood flow tomography with xenon-133

    DEFF Research Database (Denmark)

    Lassen, N A

    1985-01-01

    Cerebral blood flow (CBF) can be measured tomographically by inhalation of Xenon-133. The calculation is based on taking a sequence of tomograms during the wash-in and wash-out phase of the tracer. Due to the dynamic nature of the process, a highly sensitive and fast moving single photon emission...... of other tracers for CBF tomography using SPECT is summarized with emphasis on the 99mTc chelates that freely pass the intact blood-brain barrier. The highly sensitive brain-dedicated SPECT systems described are a prerequisite for achieving high resolution tomograms with such tracers....

  20. Nonlinear interactions in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, Donald J.; Sosnovtseva, Olga; Chon, Ki H.

    2005-01-01

    hydrostatic pressure, and plasma flow rate. The arteriolar model predicts fraction of open K channels, intracellular Ca concentration (Ca-i), potential difference, rate of actin - myosin cross bridge formation, force of contraction, and length of elastic elements, and was solved for two arteriolar segments...... resistance and glomerular capillary pressure. The model couples TGF input to voltage-gated Ca channels. It predicts autoregulation of GFR and renal blood flow, matches experimental measures of tubular pressure and macula densa NaCl concentration, and predicts TGF-induced oscillations and a faster smaller...

  1. Magnetic Resonance Imaging Measurement of Left Ventricular Blood Flow and Coronary Flow Reserve in Patients with Chronic Heart Failure due to Coronary Artery Disease

    Energy Technology Data Exchange (ETDEWEB)

    Aras, A.; Anik, Y.; Demirci, A.; Balci, N.C.; Kozdag, G.; Ural, D.; Komsuoglu, B. (Radiology Dept. and Cardiology Dept., Kocaeli Univ. School of Medicine, Kocaeli (Turkey))

    2007-11-15

    Background: Coronary sinus flow reflects global cardiac perfusion and has been used for the assessment of myocardial flow reserve, which is reduced in chronic heart failure (CHF). Coronary flow reserve (CFR) can be measured by using phase-contrast (PC) velocity-encoded cine (VEC) magnetic resonance imaging (MRI). Purpose: To quantify and compare global left ventricular (LV) perfusion and CFR in patients with CHF and in a healthy control group by measuring coronary sinus flow with PC VEC MRI, and to correlate this with global LV perfusion, segmental first-pass perfusion, and viability in the same patients. Material and Methods: Cardiac MRI was performed in 20 patients with CHF of ischemic origin and in a control group of healthy subjects (n 11) at rest and after pharmacological stress induced by i.v. dipyridamole. The MRI protocol included cine MRI, VEC MRI, first-pass perfusion, and delayed contrast-enhanced MRI for viability. Global LV perfusion was quantified by measuring coronary sinus flow on VEC MRI at rest in all subjects. CFR was determined as the ratio of global LV perfusion before and after pharmacologic stress. Results: At rest, global LV perfusion was not significantly different in patients with CHF and the control group. After administration of dipyridamole, global LV perfusion and CFR were significantly lower in patients with CHF compared to the control group (P<0.001). An inverse correlation was observed between CFR and the number of infarcted and/or ischemic segments (P = 0.083, P = 0.037). Conclusion: A combined cardiac MRI protocol including function and perfusion techniques together with VEC MRI can be used to evaluate global LV perfusion and CFR in patients with CHF. Global LV perfusion and CFR measurements may have potential in the monitoring of CHF. Impaired CFR may contribute to progressive decline in LV function in patients with CHF

  2. In vitro confocal micro-PIV measurements of blood flow in a square microchannel: the effect of the haematocrit on instantaneous velocity profiles.

    Science.gov (United States)

    Lima, Rui; Wada, Shigeo; Takeda, Motohiro; Tsubota, Ken-ichi; Yamaguchi, Takami

    2007-01-01

    A confocal microparticle image velocimetry (micro-PIV) system was used to obtain detailed information on the velocity profiles for the flow of pure water (PW) and in vitro blood (haematocrit up to 17%) in a 100-microm-square microchannel. All the measurements were made in the middle plane of the microchannel at a constant flow rate and low Reynolds number (Re=0.025). The averaged ensemble velocity profiles were found to be markedly parabolic for all the working fluids studied. When comparing the instantaneous velocity profiles of the three fluids, our results indicated that the profile shape depended on the haematocrit. Our confocal micro-PIV measurements demonstrate that the root mean square (RMS) values increase with the haematocrit implying that it is important to consider the information provided by the instantaneous velocity fields, even at low Re. The present study also examines the potential effect of the RBCs on the accuracy of the instantaneous velocity measurements.

  3. "Cognitive activity" monitored by non-invasive measurement of cerebral blood flow velocity and its application to the investigation of cerebral dominance.

    Science.gov (United States)

    Markus, H S; Boland, M

    1992-12-01

    We have developed a method of non-invasively detecting language lateralisation by measuring the increase in middle cerebral artery blood flow velocity occurring during a word association task, using transcranial Doppler ultrasonography. All exclusively right handed subjects (N = 12) showed a relative increase in left sided flow velocity during the task; mean rise was 4.04% on the left, and -0.03% on the right (p 5%) in left, compared with right, hemisphere flow velocity, and three showing only small differences between left and right sides, possibly reflecting bilateral language representation. This technique offers potential not only in studying patterns of cerebral dominance, but also in studying cognitive responses to other stimuli.

  4. Data adaptive estimation of transversal blood flow velocities

    DEFF Research Database (Denmark)

    Pirnia, E.; Jakobsson, A.; Gudmundson, E.

    2014-01-01

    The examination of blood flow inside the body may yield important information about vascular anomalies, such as possible indications of, for example, stenosis. Current Medical ultrasound systems suffer from only allowing for measuring the blood flow velocity along the direction of irradiation......, posing natural difficulties due to the complex behaviour of blood flow, and due to the natural orientation of most blood vessels. Recently, a transversal modulation scheme was introduced to induce also an oscillation along the transversal direction, thereby allowing for the measurement of also...... the transversal blood flow. In this paper, we propose a novel data-adaptive blood flow estimator exploiting this modulation scheme. Using realistic Field II simulations, the proposed estimator is shown to achieve a notable performance improvement as compared to current state-of-the-art techniques....

  5. Comparison of Global Cerebral Blood Flow Measured by Phase-Contrast Mapping MRI with O-15-H2O Positron Emission Tomography

    DEFF Research Database (Denmark)

    Vestergaard, Mark Bitsch; Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob

    2017-01-01

    Purpose To compare mean global cerebral blood flow (CBF) measured by phase-contrast mapping magnetic resonance imaging (PCM MRI) and by 15O-H2O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated in vivo...... against an accepted reference technique. Materials and Methods Same-day measurements of CBF by 15O-H2O PET and subsequently by PCM MRI were performed on 22 healthy young male volunteers. Global CBF by PET was determined by applying a one-tissue compartment model with measurement of the arterial input...... function. Flow was measured in the internal carotid and vertebral arteries by a noncardiac triggered PCM MRI sequence at 3T. The measured flow was normalized to total brain weight determined from a volume-segmented 3D T1-weighted anatomical MR-scan. Results Mean CBF was 34.9 ± 3.4 mL/100 g/min measured...

  6. Low cerebral blood flow in hypotensive perinatal distress

    DEFF Research Database (Denmark)

    Lou, H C; Lassen, N A; Friis-Hansen, B

    1977-01-01

    understood. Arterial hypoxia has been taken as the obvious mechanism but this does not fully explain the patho-anatomical findings. In the present investigation we have examined the arterial blood pressure and the cerebral blood flow in eight infants a few hours after birth. The 133Xe clearance technique...... was used for the cerebral blood flow measurements. The study confirmed that perinatal distress may be associated with low arterial blood pressure, and it was shown that cerebral blood flow is very low, 20 ml/100 g/min or less, in hypotensive perinatal distress. It is concluded that cerebral ischaemia plays...

  7. Remifentanil decreases oral tissue blood flow while maintaining internal carotid artery blood flow during sevoflurane anesthesia in rabbits.

    Science.gov (United States)

    Hirata, Atsushi; Kasahara, Masataka; Matsuura, Nobuyuki; Ichinohe, Tatsuya

    2018-03-02

    The aim of this study was to investigate the effect of remifentanil infusion on oral tissue blood flow including submandibular gland tissue blood flow (SBF) and internal carotid artery blood flow (ICBF) in rabbits during sevoflurane anesthesia. Twelve male Japan White rabbits were anesthetized with sevoflurane and remifentanil. Remifentanil was infused at 0.2 and 0.4 µg/kg/min. Measurements included circulatory variables, common and external carotid artery blood flow (CCBF, ECBF), ICBF, tongue mucosal blood flow (TMBF), masseter muscle tissue blood flow (MBF), mandibular bone marrow tissue blood flow (BBF), tongue muscle tissue blood flow (TBF) and SBF. Vascular resistances for each tissue, including the tongue mucosa, masseter muscle, mandibular bone marrow, tongue muscle and submandibular gland, were calculated by dividing the mean arterial pressure by the respective tissue blood flow. Remifentanil infusion decreased oral tissue blood flow and circulatory variables. CCBF, ECBF and ICBF did not change. The calculated vascular resistance in each oral tissue, except for the tongue mucosa, increased in an infusion-rate-dependent manner. These results showed that remifentanil infusion reduced TMBF, MBF, BBF, TBF and SBF in an infusion-rate-dependent manner without affecting ICBF under sevoflurane anesthesia.

  8. Bone blood flow after spinal paralysis in the rat

    International Nuclear Information System (INIS)

    Takahashi, H.; Yamamuro, T.; Okumura, H.; Kasai, R.; Tada, K.

    1990-01-01

    The goal of this study was to investigate the acute and chronic effects of paralysis induced by spinal cord section or sciatic neurotomy on bone blood flow in the rat. Regional bone blood flow was measured in the early stage with the hydrogen washout technique and the change of whole bone blood flow was measured in the early and the late stages with the radioactive microsphere technique. Four to 6 h after cordotomy at the level of the 13th thoracic vertebra, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.01). After hemicordotomy with rhizotomy at the same level, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.05) 6 h postoperatively. The whole bone blood flow in the denervated tibia had also increased significantly (p less than 0.05) at 6 h and at 4 and 12 weeks postoperatively. After sciatic neurotomy, the regional and the whole bone blood flow in the paralytic tibia did not change significantly. The present study demonstrated that monoplegic paralysis caused an increase in bone blood flow in the denervated hind limb from a very early stage. It was suggested that the spinal nervous system contributed to the control of bone blood flow

  9. Transcranial measurement of diffuse light reflectance from brain edema in rats: effect of change in the blood flow

    Science.gov (United States)

    Ueda, Yoshinori; Sato, Shunichi; Ooigawa, Hidetoshi; Nawashiro, Hiroshi; Saitoh, Daizoh; Shima, Katsuji; Okada, Yoshiaki; Ashida, Hiroshi; Obara, Minoru

    2005-04-01

    We assumed that edema causes a decrease in the scattering coefficient of brain tissue and hence a decrease in the intensity of diffuse reflectance from the brain. On the basis of this assumption, we attempted to transcranially detect a formation of brain edema by measuring diffuse light reflectance. In rats, edema was induced by making a cold injury in the brain. The skull was irradiated with 633-nm and 532-nm laser light delivered through an optical fiber, and the diffuse light reflectance from the brain was collected with another optical fiber. We observed that reflectance intensities were significantly decreased around the cold injury both at 633 nm and 532 nm, suggesting that scattering coefficient of brain tissue was reduced due to a formation of edema in this area. In the injury, reflectance intensity was increased at 532 nm, indicating that cerebral blood volume was decreased in this region.

  10. Regional cerebral blood flow in focal cortical epilepsy

    DEFF Research Database (Denmark)

    Hougaard, Kristina Dupont; Oikawa, T; Sveinsdottir, E

    1976-01-01

    Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were st...

  11. Regional cerebral blood flow in focal cortical epilepsy

    DEFF Research Database (Denmark)

    Hougaard, Kristina Dupont; Oikawa, T; Sveinsdottir, E

    1976-01-01

    Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were...

  12. Insuring quality during implementation of a SPEDT method of regional cerebral blood flow measurements into daily routine

    International Nuclear Information System (INIS)

    Mathiassen, B.; Landsfeldt, U.S.; Broechner-Mortensen, J.; Andersen, A.R.; Pedersen, B.; Roedbro, P.

    1995-01-01

    The present aim was to describe a method for quality insurance when a previously experimental technique is implemented for daily clinical use. Regional cerebral blood flow (rCBF) was studied in 24 patients with medically intractable complex partial epilepsy using SPECT of the Tc99m-HMPAO distribution. The colour-coded rCBF images were evaluated visually four times by four observers who classified each data set into one of four ranked classes (normal, slightly - , median - or severely abnormal). The visual analysis was compared to the results obtained by an expert (the standard). After two evaluation rounds a teaching session of image interpretation was performed with emphasis on the most difficult problem cases. The results of the primary evaluation and the yield of the teaching round was assessed by error-points depending on the magnitude of the misinterpretation of each data set. Interobserver discrepancies was analyzed by Friedman's test of variance, while intra-observer variability was evaluated by Wilcoxon's paired non-parametric test. The teaching round improved the performance of the four observers significantly (p=0.0004), but not to the wanted quality standard for all observers. The reproducibility was improved in all, but not significantly. The insurance of quality during implementation of a new diagnostic method can thus be performed in a simple way providing the steering team with identification of problems, as well as inspiration to solution of critical problems. The presented quality insurance method can easily be performed when other imaging modalities are started or when quality control of a routine method is needed. (au)

  13. Regional cerebral blood flow in the patient with brain tumor

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchida, Shohei (Okayama Univ. (Japan). School of Medicine)

    1993-06-01

    Regional cerebral blood flow (rCBF) was measured with xenon-enhanced CT (Xe-CT) in 21 cases of intracranial tumors (13 meningiomas, 5 gliomas, 3 metastatic brain tumors). Peritumoral edema was graded as mild, moderate or severe based on the extent of edema on CT and MRI. According to intratumoral blood flow distribution patterns, three patterns were classified as central type with relatively high blood flow at the center of the tumor, homogeneous type with an almost homogeneous blood flow distribution, and marginal type with relatively high blood flow at the periphery of the tumor. High grade astrocytoma and metastatic brain tumor showed marginal type blood flow and moderate or severe edema except in one case. Five meningiomas with severe peritumoral edema revealed marginal type blood flow and four with mild peritumoral edema showed central type blood flow, except for one case. No correlation was found between the extent of peritumoral edema and histological subtype, tumor size, location, duration of clinical history, vascularization on angiogram, and mean blood flow in the tumor. These results suggest that blood flow distribution patterns within the tumor may affect the extension of peritumoral edema. Pre- and postoperative rCBFs were evaluated with Xe-CT and IMP-SPECT in 7 cases, mean rCBF of peritumoral edema was 6.2 ml/100 g/min preoperatively, and discrepancy between rCBF on Xe-CT and that on IMP-SPECT was shown in the remote cortical region ipsilateral to the tumor. Postoperative rCBF revealed an improved blood flow in both adjacent and remote areas, suggesting that the decreased blood flow associated with brain tumors might be relieved after surgery. (author) 53 refs.

  14. Regional cerebral blood flow in the patient with brain tumor

    International Nuclear Information System (INIS)

    Tsuchida, Shohei

    1993-01-01

    Regional cerebral blood flow (rCBF) was measured with xenon-enhanced CT (Xe-CT) in 21 cases of intracranial tumors (13 meningiomas, 5 gliomas, 3 metastatic brain tumors). Peritumoral edema was graded as mild, moderate or severe based on the extent of edema on CT and MRI. According to intratumoral blood flow distribution patterns, three patterns were classified as central type with relatively high blood flow at the center of the tumor, homogeneous type with an almost homogeneous blood flow distribution, and marginal type with relatively high blood flow at the periphery of the tumor. High grade astrocytoma and metastatic brain tumor showed marginal type blood flow and moderate or severe edema except in one case. Five meningiomas with severe peritumoral edema revealed marginal type blood flow and four with mild peritumoral edema showed central type blood flow, except for one case. No correlation was found between the extent of peritumoral edema and histological subtype, tumor size, location, duration of clinical history, vascularization on angiogram, and mean blood flow in the tumor. These results suggest that blood flow distribution patterns within the tumor may affect the extension of peritumoral edema. Pre- and postoperative rCBFs were evaluated with Xe-CT and IMP-SPECT in 7 cases, mean rCBF of peritumoral edema was 6.2 ml/100 g/min preoperatively, and discrepancy between rCBF on Xe-CT and that on IMP-SPECT was shown in the remote cortical region ipsilateral to the tumor. Postoperative rCBF revealed an improved blood flow in both adjacent and remote areas, suggesting that the decreased blood flow associated with brain tumors might be relieved after surgery. (author) 53 refs

  15. Simultaneous measurement of local glucose utilization and blood flow in the rat brain: an autoradiographic method using two tracers labeled with carbon-14

    International Nuclear Information System (INIS)

    Furlow, T.W. Jr.; Martin, R.M.; Harrison, L.E.

    1983-01-01

    A simplified technique that uses two radionuclide tracers has been devised to measure local cerebral glucose utilization (ICGU) and local cerebral blood flow (ICBF) in the same rat. The method employs [ 14 C]-2-deoxyglucose and [ 14 C]iodoantipyrine to produce an autoradiogram before and another after extraction into chloroform of the [ 14 C]iodoantipyrine from the brain sections. The chloroform-extracted autoradiogram yields ICGU, and the difference in tissue carbon-14 concentration between the two autoradiograms permits calculation of ICBF. The double-isotope technique provides values of ICGU and ICBF that are statistically indistinguishable from those derived from conventional single-isotope methods

  16. Gender differences in regional cerebral blood flow

    International Nuclear Information System (INIS)

    Gur, R.E.; Gur, R.C.

    1990-01-01

    Gender differences have been noted in neurobehavioral studies. The 133xenon inhalation method for measuring regional cerebral blood flow (rCBF) can contribute to the understanding of the neural basis of gender differences in brain function. Few studies have examined gender differences in rCBF. In studies of normal subjects, women have higher rates of CBF than men, and this is related to age. Usually by the sixth decade men and women have similar flow rates. Fewer studies on rCBF in schizophrenia have examined sex differences. The pattern of higher flows for females maintains, but its correlates with gender differences in clinical as well as other parameters of brain function remain to be examined

  17. Regional cerebral blood flow in schizophrenia

    International Nuclear Information System (INIS)

    Kanoh, Masayuki

    1989-01-01

    Regional cerebral blood flow (rCBF) was measured at rest using the 133 Xe inhalation technique in 40 DSM-III-diagnosed schizophrenics (22 males, 18 females: mean age 35.0 years, range 20-49 years) and 31 age-and sex-matched normal controls (16 males, 15 females: mean age 34.3 years, range 21-49 years). The absolute value (AV) and the percent value (PV) of the rCBF in schizophrenics were compared with those in controls. Correlations between rCBF and the Brief Psychiatric Rating Scale (BPRS) scores or the performance of Wisconsin Card Sorting Test (WCST) were examined in schizophrenics. Schizophrenics showed significantly lower AVs in all brain regions examined and a significantly lower PV in the left superior frontal region than controls. The hyperfrontal rCBF distribution which was found in both hemispheres in controls, was absent in the left hemisphere in schizophrenics. In schizophrenics, superior frontal blood flows were significantly negatively correlated with the negative symptom scores of the BPRS but not with the total scores and the positive symptom scores of the BPRS. In schizophrenics, inferior frontal blood flows were significantly correlated with the number of sorting categories achieved. These results indicate that rCBF in schizophrenia is reduced in the whole brain and especially in the left superior frontal region. These findings suggest a frontal lobe dysfunction in schizophrenia. (author)

  18. Tomographic multiphase flow measurement

    International Nuclear Information System (INIS)

    Sætre, C.; Johansen, G.A.; Tjugum, S.A.

    2012-01-01

    Measurement of multiphase flow of gas, oil and water is not at all trivial and in spite of considerable achievements over the past two decades, important challenges remain (). These are related to reducing measurement uncertainties arising from variations in the flow regime, improving long term stability and developing new means for calibration, adjustment and verification of the multiphase flow meters. This work focuses on the first two issues using multi gamma beam (MGB) measurements for identification of the type of flow regime. Further gamma ray tomographic measurements are used for reference of the gas/liquid distribution. For the MGB method one Am-241 source with principal emission at 59.5 keV is used because this relatively low energy enables efficient collimation and thereby shaping of the beams, as well as compact detectors. One detector is placed diametrically opposite the source whereas the second is positioned to the side so that this beam is close to the pipe wall. The principle is then straight forward to compare the measured intensities of these detectors and through that identify the flow pattern, i.e. the instantaneous cross-sectional gas-liquid distribution. The measurement setup also includes Compton scattering measurements, which can provide information about the changes in the water salinity for flow segments with high water liquid ratio and low gas fractions. By measuring the transmitted intensity in short time slots (<100ms), rapid regime variations are revealed. From this we can select the time sections suitable for salinity measurements. Since the salinity variations change at the time scale of hours, a running average can be performed to increase the accuracy of the measurements. Recent results of this work will be presented here. - Highlights: ► Multiphase flow gas-fraction and flow regime measurements by multi gamma ray beams. ► High-speed gamma ray tomograph as reference for the flow pattern and gas fraction. ► Dual modality

  19. Effects of Red Blood Cell Aggregation on the Apparent Viscosity of Blood Flow in Tubes.

    Science.gov (United States)

    Hitt, Darren L.; Lowe, Mary L.

    1996-11-01

    In arterioles and venules (20-200μ diameter), the low shear rates enable red blood cells to form aggregate structures of varying sizes and morphology. The size and distribution of the aggregates affect the flow impedance within a microvascular network; this effect may be characterized by an "apparent viscosity". In this study, we measure the apparent viscosity of blood flow in 50μ glass tubes as a function of shear rate and red blood cell volume fraction (hematocrit); for a fixed tube geometry and an imposed flow rate, the viscosity is determined by measuring the pressure drop across the tube. To correlate the apparent viscosity with the size and spatial distribution of the aggregates in the flow, video images of the flow are recorded and analyzed using power spectral techniques. Pig blood and sheep blood are used as the models for aggregating and non-aggregating blood, respectively. Supported by NSF PFF Award CTS-9253633

  20. Subcutaneous blood flow during insulin-induced hypoglycaemia

    DEFF Research Database (Denmark)

    Hilsted, J; Madsbad, S; Sestoft, L

    1982-01-01

    Subcutaneous blood flow was measured preceding insulin-induced hypoglycaemia, at the onset of hypoglycaemic symptoms and 2 h later in juvenile diabetics with and without autonomic neuropathy and in normal males. In all groups subcutaneous blood flow decreased at the onset of hypoglycaemic symptoms...... compared with pre-hypoglycaemic flow. Two hours after onset of hypoglycaemic symptoms, subcutaneous blood flow was still significantly decreased compared with pre-hypoglycaemic flow. In normal subjects local nerve blockade had no effect on blood flow changes during hypoglycaemia, whereas local alpha......-receptor blockade abolished the vasoconstrictor response. We suggest that circulating catecholamines stimulating vascular alpha-receptors are probably responsible for flow reduction in the subcutaneous tissue during hypoglycaemia....

  1. Effects of combined xenon and hypothermia on cerebral blood flow and oxygen consumption in newborn piglets measured with a time-resolved near-infrared technique

    Science.gov (United States)

    Fazel Bakhsheshi, Mohammad; Hadway, Jennifer; Morrison, Laura B.; Diop, Mamadou; St. Lawrence, Keith; Lee, Ting-Yim

    2013-02-01

    Mild hypothermia (HT), in which the brain is cooled to 32-33°C, has been shown to be neuroprotective for neurological emergencies such as head trauma and neonatal asphyxia. Xenon (Xe), a scarce and expensive anesthetic gas, has also shown great promise as a neuroprotectant, particularly when combined with HT. The purpose of the present study was to investigate the combined effect of Xe and HT on the cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF). A closed circuit re-breathing system was used to deliver the Xe in order to make the treatment efficient and economical. A bolus-tracking method using indocyanine green (ICG) as a flow tracer with time-resolved near-infrared (TR-NIR) technique was used to measure CBF and CMRO2 in newborn piglets.

  2. Local application of 133Xenon for measurement of regional cerebral blood flow (rCBF) during halothane, enflurane, and isoflurane anesthesia in humans

    International Nuclear Information System (INIS)

    Eintrei, C.; Leszniewski, W.; Carlsson, C.

    1985-01-01

    It is well known that halothane causes an increase in cerebral blood flow (CBF). In this study the effects of halothane, enflurane, and isoflurane on regional cerebral blood flow (rCBF) in humans were determined in the presence of 70% N 2 O at a combined MAC concentration of 1.5. CBF was determined in 24 patients from the washout of locally applied 133 Xenon with the use of an external scintillation. All 24 patients (control n = 6, halothane n = 6, enflurane n = 6, and isoflurane n = 6) were undergoing neurosurgical procedures. All patients were anesthetized with thiopental, fentanyl, droperidol, and 70% N 2 O in oxygen and paralyzed with pancuronium. The measurements were performed after the dura had been opened and before definitive surgery. The first measurement was done in the absence of any volatile agent, and the wash-out curve was registered for 6 min. The second measurement was done after one of the volatile agents had been added for at least 20 min and had reached a concentration of 0.58% for halothane, 1.14% for enflurane, or 1.0% for isoflurane in the expiratory gases in order to obtain about 1.5 MAC with each volatile anesthetic. The anesthetic concentrations were measured with the Engstroem multigas analyzer EMMA. The physiologic variables changed very little throughout the period of observation. Body temperature, heart rate, blood pressure, PaCO 2 , and PaO 2 were stable. Ephedrine was used to maintain a stable arterial pressure. At approximately 1.5 MAC, halothane (plus N 2 O) increased rCBF to nearly three times (166%) the control value, while enflurane induced only a slight increase (35%) in rCBF

  3. The Role of Blood Flow and Blood Flow Modifiers in Clinical Hyperthermia Therapy

    Science.gov (United States)

    Olch, Arthur Jacob

    A quantitative assessment of the effect of localized magnetic-loop hyperthermia on blood flow was performed on 12 patients (19 tumor studies) using the Xenon-133 clearance method. After it was discovered that blood flow in most of the tumors increased in response to needle injection, a physiologically based, one compartment model was developed that included both a hyperemic (transient) and a steady state component. In the tumors of six patients, increases in blood flow induced by heat were also observed. The same model was used to describe the measured clearance data for both types of hyperemic response. The ability of tumor vessels to respond dynamically to stress and the degree of response may be predictive of tumor heating efficiency and subsequent therapeutic response. Many tumors treated by hyperthermia, therefore, do not reach therapeutic temperatures (42(DEGREES)C). One explanation for this may be that some tumors react to thermal stress in a manner similar to normal tissues; i.e., they increase blood flow during hyperthermia in order to dissipate heat. Higher temperatures might be achieved in these heat-resistant tumors by administering vasoconstrictive agents in an effort to reduce blood flow. In the second part of this research study, the extent to which pharmacologic inhibition of local blood flow might allow higher temperatures to develop in normal muscles exposed to localized radiofrequency hyperthermia was determined. It was found that the local muscle temperature rise could be increased by at least 90% in dogs and rabbits with the use of a local vasoconstrictive drug.

  4. Role of blood flow and blood flow modifiers in clinical hyperthermia therapy

    International Nuclear Information System (INIS)

    Olch, A.J.

    1986-01-01

    A quantitative assessment of the effect of localized magnetic-loop hyperthermia on blood flow was performed on 12 patients (19 tumor studies) using the Xenon-133 clearance method. After it was discovered that blood flow in most of the tumors increased in response to needle injection, a physiologically based, one compartment model was developed that included both a hyperemic (transient) and a steady state component. In the tumors of six patients, increases in blood flow induced by heat were also observed. The same model was used to describe the measured clearance data for both types of hyperemic response. The ability of tumor vessels to respond dynamically to stress and the degree of response may be predictive of tumor heating efficiency and subsequent therapeutic response. Many tumors treated by hyperthermia, therefore, do not reach therapeutic temperatures (42 0 C). One explanation for this may be that some tumors react to thermal stress in a manner similar to normal tissues; i.e., they increase blood flow during hyperthermia in order to dissipate heat. Higher temperatures might be achieved in these heat-resistant tumors by administering vasoconstrictive agents in an effort to reduce blood flow. In the second part of this research study, the extent to which pharmacologic inhibition of local blood flow might allow higher temperatures to develop in normal muscles exposed to localized radiofrequency hyperthermia was determined. It was found that the local muscle temperature rise could be increased by at least 90% in dogs and rabbits with the use of a local vasoconstrictive drug

  5. Regional cerebral blood flow in childhood headache

    International Nuclear Information System (INIS)

    Roach, E.S.; Stump, D.A.

    1989-01-01

    Regional cerebral blood flow (rCBF) was measured in 16 cranial regions in 23 children and adolescents with frequent headaches using the non-invasive Xenon-133 inhalation technique. Blood flow response to 5% carbon dioxide (CO2) was also determined in 21 patients, while response to 50% oxygen was measured in the two patients with hemoglobinopathy. Included were 10 patients with a clinical diagnosis of migraine, 4 with musculoskeletal headaches, and 3 with features of both types. Also studied were 2 patients with primary thrombocythemia, 2 patients with hemoglobinopathy and headaches, 1 patient with polycythemia, and 1 with headaches following trauma. With two exceptions, rCBF determinations were done during an asymptomatic period. Baseline rCBF values tended to be higher in these young patients than in young adults done in our laboratory. Localized reduction in the expected blood flow surge after CO2 inhalation, most often noted posteriorly, was seen in 8 of the 13 vascular headaches, but in none of the musculoskeletal headache group. Both patients with primary thrombocythemia had normal baseline flow values and altered responsiveness to CO2 similar to that seen in migraineurs; thus, the frequently reported headache and transient neurologic signs with primary thrombocythemia are probably not due to microvascular obstruction as previously suggested. These data support the concept of pediatric migraine as a disorder of vasomotor function and also add to our knowledge of normal rCBF values in younger patients. Demonstration of altered vasomotor reactivity to CO2 could prove helpful in children whose headache is atypical

  6. A simple method for measurement of cerebral blood flow using 123I-IMP SPECT with calibrated standard input function by one point blood sampling. Validation of calibration by one point venous blood sampling as a substitute for arterial blood sampling

    International Nuclear Information System (INIS)

    Ito, Hiroshi; Akaizawa, Takashi; Goto, Ryoui

    1994-01-01

    In a simplified method for measurement of cerebral blood flow using one 123 I-IMP SPECT scan and one point arterial blood sampling (Autoradiography method), input function is obtained by calibrating a standard input function by one point arterial blood sampling. A purpose of this study is validation of calibration by one point venous blood sampling as a substitute for one point arterial blood sampling. After intravenous infusion of 123 I-IMP, frequent arterial and venous blood sampling were simultaneously performed on 12 patients of CNS disease without any heart and lung disease and 5 normal volunteers. The radioactivity ratio of venous whole blood which obtained from cutaneous cubital vein to arterial whole blood were 0.76±0.08, 0.80±0.05, 0.81±0.06, 0.83±0.11 at 10, 20, 30, 50 min after 123 I-IMP infusion, respectively. The venous blood radioactivities were always 20% lower than those of arterial blood radioactivity during 50 min. However, the ratio which obtained from cutaneous dorsal hand vein to artery were 0.93±0.02, 0.94±0.05, 0.98±0.04, 0.98±0.03, at 10, 20, 30, 50 min after 123 I-IMP infusion, respectively. The venous blood radioactivity was consistent with artery. These indicate that arterio-venous difference of radioactivity in a peripheral cutaneous vein like a dorsal hand vein is minimal due to arteriovenous shunt in palm. Therefore, a substitution by blood sampling from cutaneous dorsal hand vein for artery will be possible. Optimized time for venous blood sampling evaluated by error analysis was 20 min after 123 I-IMP infusion, which is 10 min later than that of arterial blood sampling. (author)

  7. Feasibility of measuring renal blood flow by phase-contrast magnetic resonance imaging in patients with autosomal dominant polycystic kidney disease

    Energy Technology Data Exchange (ETDEWEB)

    Spithoven, E.M.; Meijer, E.; Boertien, W.E.; Gaillard, C.A.J.M.; Jong, P.E. de; Gansevoort, R.T. [University of Groningen, Department of Nephrology, Community and Occupational Medicine, University Medical Center Groningen, PO Box 30.001, RB Groningen (Netherlands); Borns, C.; Kappert, P.; Greuter, M.J.W.; Jagt, E. van der [University of Groningen, Department of Radiology, Community and Occupational Medicine, University Medical Center Groningen, Groningen (Netherlands); Vart, P. [University of Groningen, Department of Health Sciences, Community and Occupational Medicine, University Medical Center Groningen, Groningen (Netherlands)

    2016-03-15

    Renal blood flow (RBF) has been shown to predict disease progression in autosomal dominant polycystic kidney disease (ADPKD). We investigated the feasibility and accuracy of phase-contrast RBF by MRI (RBF{sub MRI}) in ADPKD patients with a wide range of estimated glomerular filtration rate (eGFR) values. First, we validated RBF{sub MRI} measurement using phantoms simulating renal artery hemodynamics. Thereafter, we investigated in a test-set of 21 patients intra- and inter-observer coefficient of variation of RBF{sub MRI}. After validation, we measured RBF{sub MRI} in a cohort of 91 patients and compared the variability explained by characteristics indicative for disease severity for RBF{sub MRI} and RBF measured by continuous hippuran infusion. The correlation in flow measurement using phantoms by phase-contrast MRI was high and fluid collection was high (CCC=0.969). Technical problems that precluded RBF{sub MRI} measurement occurred predominantly in patients with a lower eGFR (34% vs. 16%). In subjects with higher eGFRs, variability in RBF explained by disease characteristics was similar for RBF{sub MRI} compared to RBF{sub Hip,} whereas in subjects with lower eGFRs, this was significantly less for RBF{sub MRI}. Our study shows that RBF can be measured accurately in ADPKD patients by phase-contrast, but this technique may be less feasible in subjects with a lower eGFR. (orig.)

  8. Modified Beer-Lambert law for blood flow

    Science.gov (United States)

    Baker, Wesley B.; Parthasarathy, Ashwin B.; Busch, David R.; Mesquita, Rickson C.; Greenberg, Joel H.; Yodh, A. G.

    2015-03-01

    The modified Beer-Lambert law is among the most widely used approaches for analysis of near-infrared spectroscopy (NIRS) reflectance signals for measurements of tissue blood volume and oxygenation. Briefly, the modified Beer-Lambert paradigm is a scheme to derive changes in tissue optical properties based on continuous-wave (CW) diffuse optical intensity measurements. In its simplest form, the scheme relates differential changes in light transmission (in any geometry) to differential changes in tissue absorption. Here we extend this paradigm to the measurement of tissue blood flow by diffuse correlation spectroscopy (DCS). In the new approach, differential changes of the intensity temporal auto-correlation function at a single delay-time are related to differential changes in blood flow. The key theoretical results for measurement of blood flow changes in any tissue geometry are derived, and we demonstrate the new method to monitor cerebral blood flow in a pig under conditions wherein the semi-infinite geometry approximation is fairly good. Specifically, the drug dinitrophenol was injected in the pig to induce a gradual 200% increase in cerebral blood flow, as measured with MRI velocity flow mapping and by DCS. The modified Beer-Lambert law for flow accurately recovered these flow changes using only a single delay-time in the intensity auto-correlation function curve. The scheme offers increased DCS measurement speed of blood flow. Further, the same techniques using the modified Beer-Lambert law to filter out superficial tissue effects in NIRS measurements of deep tissues can be applied to the DCS modified Beer-Lambert law for blood flow monitoring of deep tissues.

  9. The Physics of Coronary Blood Flow

    CERN Document Server

    Zamir, M

    2005-01-01

    Coronary blood flow is blood flow to the heart for its own metabolic needs. In the most common form of heart disease there is a disruption in this flow because of obstructive disease in the vessels that carry the flow. The subject of coronary blood flow is therefore associated mostly with the pathophysiology of this disease, rarely with dynamics or physics. Yet, the system responsible for coronary blood flow, namely the "coronary circulation," is a highly sophisticated dynamical system in which the dynamics and physics of the flow are as important as the integrity of the conducting vessels. While an obstruction in the conducting vessels is a fairly obvious and clearly visible cause of disruption in coronary blood flow, any discord in the complex dynamics of the system can cause an equally grave, though less conspicuous, disruption in the flow. This book is devoted specifically to the dynamics and physics of coronary blood flow. While relevance to the clinical and pathophysiological issues is clearly maintaine...

  10. Planetary heat flow measurements.

    Science.gov (United States)

    Hagermann, Axel

    2005-12-15

    The year 2005 marks the 35th anniversary of the Apollo 13 mission, probably the most successful failure in the history of manned spaceflight. Naturally, Apollo 13's scientific payload is far less known than the spectacular accident and subsequent rescue of its crew. Among other instruments, it carried the first instrument designed to measure the flux of heat on a planetary body other than Earth. The year 2005 also should have marked the launch of the Japanese LUNAR-A mission, and ESA's Rosetta mission is slowly approaching comet Churyumov-Gerasimenko. Both missions carry penetrators to study the heat flow from their target bodies. What is so interesting about planetary heat flow? What can we learn from it and how do we measure it?Not only the Sun, but all planets in the Solar System are essentially heat engines. Various heat sources or heat reservoirs drive intrinsic and surface processes, causing 'dead balls of rock, ice or gas' to evolve dynamically over time, driving convection that powers tectonic processes and spawns magnetic fields. The heat flow constrains models of the thermal evolution of a planet and also its composition because it provides an upper limit for the bulk abundance of radioactive elements. On Earth, the global variation of heat flow also reflects the tectonic activity: heat flow increases towards the young ocean ridges, whereas it is rather low on the old continental shields. It is not surprising that surface heat flow measurements, or even estimates, where performed, contributed greatly to our understanding of what happens inside the planets. In this article, I will review the results and the methods used in past heat flow measurements and speculate on the targets and design of future experiments.

  11. Sequential topographical portrayal of myocardial blood flow

    International Nuclear Information System (INIS)

    Richeson, J.F.; Waag, R.C.; Zwierzynski, D.; Schenk, E.A.

    1989-01-01

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

  12. Radioisotopic flow scanning for portal blood flow and portal hypertension

    International Nuclear Information System (INIS)

    Hesdorffer, C.S.; Bezwoda, W.R.; Danilewitz, M.D.; Esser, J.D.; Tobias, M.

    1987-01-01

    The use of a simple, noninvasive, isotope scanning technique for the determination of relative portal blood flow and detection of portal hypertension is described. Using this technique the presence of portal hypertension was demonstrated in seven of nine patients known to have elevated portal venous pressure. By contrast, esophageal varices were demonstrated in only five of these patients, illustrating the potential value of the method. Furthermore, this technique has been adapted to the study of portal blood flow in patients with myeloproliferative disorders with splenomegaly but without disturbances in hepatic architecture. Results demonstrate that the high relative splenic flow resulting from the presence of splenomegaly may in turn be associated with elevated relative portal blood flow and portal hypertension. The theoretic reasons for the development of flow-related portal hypertension and its relationship to splenic blood flow are discussed

  13. Blood flow velocity in migraine attacks - a transcranial Doppler study

    International Nuclear Information System (INIS)

    Zwetsloot, C.P.; Caekebeke, J.F.V.; Jansen, J.C.; Odink, J.; Ferrari, M.D.

    1991-01-01

    A pulsed Doppler device was used to measure blood flow velocities in the common carotid artery, the extracranial part of the internal carotid artery, the external carotid artery, the middle cerebral artery, and the anterior cerebral artery in 31 migraneurs without aura (n=27) and with aura (n=4), both during and ouside an attack. The aims were to compare blood flow velocity during and between migraine attacks and to study asymmetries of the blood flow velocity. Compared with blood flow velocity values obtained in the attack-free interval, blood flow velocity was lower during attacks without aura in both common carotid arteries, but not in the other extra- and intracranial vessels which were examined. However, during attacks of migraine with aura, blood flow velocity tended to be lower in all examined vessels. There were no asymmetries of the blood flow velocity. It is suggested that during migraine attacks without aura there is a dissociation in blood flow regulation in the common carotid and middle cerebral arteries. 20 refs., 2 tabs

  14. The effect of hyperosmotic solutions on the hepatic blood flow

    DEFF Research Database (Denmark)

    Winkler, K; Henriksen, Jens Henrik Sahl; Tygstrup, N

    1993-01-01

    The present study was undertaken in order to measure the effect of hyperosmotic solutions on portal and hepatic blood flow. In five anaesthetized pigs without arterial blood supply to the liver, portal blood flow rate was measured (electromagnetic flowmeter) during 5 min lasting intravenous...... infusions of hyperosmotic galactose (50%, 84-100 ml) and mannitol (25%, 100 ml), with physiological saline (100 ml) as control. Portal blood flow increased to a peak value of (39% [P = 0.06] galactose and 37%, [P = 0.06], mannitol) soon after stop of the hyperosmotic infusion. For galactose the change ended...... somewhat earlier than for mannitol. Saline induced a minor increase (15%). Similarly, increments of, on average, 144% of the hepatic blood flow rate was seen in six patients with cirrhosis, following infusion of hyperosmotic galactose, the increase being more pronounced than in the pigs. The causes...

  15. Leg blood flow during static exercise.

    Science.gov (United States)

    Kilbom, A; Persson, J

    1982-01-01

    Leg blood flow was studied with the constant infusion dye technique during static exercise of the thigh muscles (quadriceps) and during hand-grips at 15 and 25-30% of MVC. Blood flow and oxygen uptake in the leg increased in quadriceps exercise and reached their highest values (around 1.21/min and 165 ml/min respectively) at 25-30% of MVC, whereas leg vascular resistance decreased. Regional circulatory adaptations and the oxygen uptake - leg blood flow relationship were in close agreement with the responses found in dynamic leg exercise. In view of the marked rise in intramuscular pressure previously observed during quadriceps contractions, a restriction of blood flow and an increased vascular resistance had been expected. Involuntary activation of leg muscles other than the quadriceps may explain the finding. Contractions of the contralateral quadriceps induced a slight increase in leg blood flow, whereas hand-grips had no influence on blood flow or vascular resistance in the leg. The distribution of the cardiac output during static contractions is discussed, and it is concluded that during hand-grips the increase in blood flow is predominantly distributed to the upper part of the body.

  16. Clinical aviation medicine research : comparison of simultaneous measurements of intra-aortic and auscultatory blood pressures with pressure-flow dynamics during rest and excercise.

    Science.gov (United States)

    1966-10-01

    The study provides correlative information with respect to the comparative accuracy of the traditional 'cuff' clinical method of obtaining blood pressure and the laboratory catheterization procedure which measures actual blood pressure. The informati...

  17. Hemodilution increases cerebral blood flow in acute ischemic stroke

    International Nuclear Information System (INIS)

    Vorstrup, S.; Andersen, A.; Juhler, M.; Brun, B.; Boysen, G.

    1989-01-01

    We measured cerebral blood flow in 10 consecutive, but selected, patients with acute ischemic stroke (less than 48 hours after onset) before and after hemodilution. Cerebral blood flow was measured by xenon-133 inhalation and emission tomography, and only patients with focal hypoperfusion in clinically relevant areas were included. Hemodilution was done according to the hematocrit level: for a hematocrit greater than or equal to 42%, 500 ml whole blood was drawn and replaced by the same volume of dextran 40; for a hematocrit between 37% and 42%, only 250 ml whole blood was drawn and replaced by 500 cc of dextran 40. Mean hematocrit was reduced by 16%, from 46 +/- 5% (SD) to 39 +/- 5% (SD) (p less than 0.001). Cerebral blood flow increased in both hemispheres by an average of 20.9% (p less than 0.001). Regional cerebral blood flow increased in the ischemic areas in all cases, on an average of 21.4 +/- 12.0% (SD) (p less than 0.001). In three patients, a significant redistribution of flow in favor of the hypoperfused areas was observed, and in six patients, the fractional cerebral blood flow increase in the hypoperfused areas was of the same magnitude as in the remainder of the brain. In the last patient, cerebral blood flow increased relatively less in the ischemic areas. Our findings show that cerebral blood flow increases in the ischemic areas after hemodilution therapy in stroke patients. The marked regional cerebral blood flow increase seen in some patients could imply an improved oxygen delivery to the ischemic tissue

  18. Structural power flow measurement

    Energy Technology Data Exchange (ETDEWEB)

    Falter, K.J.; Keltie, R.F.

    1988-12-01

    Previous investigations of structural power flow through beam-like structures resulted in some unexplained anomalies in the calculated data. In order to develop structural power flow measurement as a viable technique for machine tool design, the causes of these anomalies needed to be found. Once found, techniques for eliminating the errors could be developed. Error sources were found in the experimental apparatus itself as well as in the instrumentation. Although flexural waves are the carriers of power in the experimental apparatus, at some frequencies longitudinal waves were excited which were picked up by the accelerometers and altered power measurements. Errors were found in the phase and gain response of the sensors and amplifiers used for measurement. A transfer function correction technique was employed to compensate for these instrumentation errors.

  19. Nasal mucosal blood flow after intranasal allergen challenge

    International Nuclear Information System (INIS)

    Holmberg, K.; Bake, B.; Pipkorn, U.

    1988-01-01

    The nasal mucosal blood flow in patients with allergic rhinitis was determined at nasal allergen challenges with the 133 Xenon washout method. Determinations were made in 12 subjects before and 15 minutes after challenge with diluent and increasing doses of allergen. The time course was followed in eight subjects by means of repeated measurements during 1 hour after a single allergen dose. Finally, the blood flow was measured after unilateral allergen challenge in the contralateral nasal cavity. A dose-dependent decrease in blood flow was found after nasal challenge with increasing doses of allergens, whereas challenge with diluent alone did not induce any changes. The highest allergen dose, which also induced pronounced nasal symptoms, resulted in a decrease in blood flow of 25% (p less than 0.001). The time-course study demonstrated a maximum decrease in blood flow 10 to 20 minutes after challenge and then a gradual return to baseline. Unilateral allergen challenge resulted in a decrease in blood flow in the contralateral, unchallenged nasal cavity, suggesting that part of the allergen-induced changes in blood flow were reflex mediated

  20. Rat muscle blood flows during high-speed locomotion

    International Nuclear Information System (INIS)

    Armstrong, R.B.; Laughlin, M.H.

    1985-01-01

    We previously studied blood flow distribution within and among rat muscles as a function of speed from walking (15 m/min) through galloping (75 m/min) on a motor-driven treadmill. The results showed that muscle blood flows continued to increase as a function of speed through 75 m/min. The purpose of the present study was to have rats run up to maximal treadmill speeds to determine if blood flows in the muscles reach a plateau as a function of running speed over the animals normal range of locomotory speeds. Muscle blood flows were measured with radiolabeled microspheres at 1 min of running at 75, 90, and 105 m/min in male Sprague-Dawley rats. The data indicate that even at these relatively high treadmill speeds there was still no clear evidence of a plateau in blood flow in most of the hindlimb muscles. Flows in most muscles continued to increase as a function of speed. These observed patterns of blood flow vs. running speed may have resulted from the rigorous selection of rats that were capable of performing the high-intensity exercise and thus only be representative of a highly specific population of animals. On the other hand, the data could be interpreted to indicate that the cardiovascular potential during exercise is considerably higher in laboratory rats than has normally been assumed and that inadequate blood flow delivery to the muscles does not serve as a major limitation to their locomotory performance

  1. Regional cerebral blood flow measurements by a noninvasive microsphere method using {sup 123}I-IMP. Comparison with the modified fractional uptake method and the continuous arterial blood sampling method

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Seigo; Matsuda, Hiroshi; Tanizaki, Hiroshi; Ogawa, Masafumi [National Center Hospital for Mental, Nervous, and Muscular Disorders, NCNP, Kodaira, Tokyo (Japan); Miyazaki, Yoshiharu; Yonekura, Yoshiharu

    1998-04-01

    A noninvasive microsphere method using N-isopropyl-p-({sup 123}I)iodoamphetamine ({sup 123}I-IMP), developed by Yonekura et al., was performed in 10 patients with neurological diseases to quantify regional cerebral blood flow (rCBF). Regional CBF values by this method were compared with rCBF values simultaneously estimated from both the modified fractional uptake (FU) method using cardiac output developed by Miyazaki et al. and the conventional method with continuous arterial blood sampling. In comparison, we designated the factor which converted raw SPECT voxel counts to rCBF values as a CBF factor. A highly significant correlation (r=0.962, p<0.001) was obtained in the CBF factors between the present method and the continuous arterial blood sampling method. The CBF factors by the present method were only 2.7% higher on the average than those by the continuous arterial blood sampling method. There were significant correlation (r=0.811 and r=O.798, p<0.001) in the CBF factor between modified FU method (threshold for estimating total brain SPECT counts; 10% and 30% respectively) and the continuous arterial blood sampling method. However, the CBF factors of the modified FU method showed 31.4% and 62.3% higher on the average (threshold; 10% and 30% respectively) than those by the continuous arterial blood sampling method. In conclusion, this newly developed method for rCBF measurements was considered to be useful for routine clinical studies without any blood sampling. (author)

  2. Regional cerebral blood flow measurements by a noninvasive microsphere method using 123I-IMP. Comparison with the modified fractional uptake method and the continuous arterial blood sampling method

    International Nuclear Information System (INIS)

    Nakano, Seigo; Matsuda, Hiroshi; Tanizaki, Hiroshi; Ogawa, Masafumi; Miyazaki, Yoshiharu; Yonekura, Yoshiharu

    1998-01-01

    A noninvasive microsphere method using N-isopropyl-p-( 123 I)iodoamphetamine ( 123 I-IMP), developed by Yonekura et al., was performed in 10 patients with neurological diseases to quantify regional cerebral blood flow (rCBF). Regional CBF values by this method were compared with rCBF values simultaneously estimated from both the modified fractional uptake (FU) method using cardiac output developed by Miyazaki et al. and the conventional method with continuous arterial blood sampling. In comparison, we designated the factor which converted raw SPECT voxel counts to rCBF values as a CBF factor. A highly significant correlation (r=0.962, p<0.001) was obtained in the CBF factors between the present method and the continuous arterial blood sampling method. The CBF factors by the present method were only 2.7% higher on the average than those by the continuous arterial blood sampling method. There were significant correlation (r=0.811 and r=O.798, p<0.001) in the CBF factor between modified FU method (threshold for estimating total brain SPECT counts; 10% and 30% respectively) and the continuous arterial blood sampling method. However, the CBF factors of the modified FU method showed 31.4% and 62.3% higher on the average (threshold; 10% and 30% respectively) than those by the continuous arterial blood sampling method. In conclusion, this newly developed method for rCBF measurements was considered to be useful for routine clinical studies without any blood sampling. (author)

  3. Development of quantification analysis software for measuring regional cerebral blood flow by the modified split-dose method with 123I-IMP before and after acetazolamide loading

    International Nuclear Information System (INIS)

    Nagaki, Akio; Kobara, Kouichi; Matsutomo, Norikazu

    2003-01-01

    We developed a quantification analysis software program for measuring regional cerebral blood flow (rCBF) at rest and under acetazolamide (ACZ) stress by the modified split-dose (MSD) method with iodine-123 N-isopropyl-p-iodoamphetamine (IMP) and compared the rCBF values measured by the MSD method and by the split dose 123 I-IMP SPECT (SD) method requiring one continuous withdrawal of arterial blood. Since the MSD method allows the input of two arterial blood sampling parameter values, the background subtraction procedure for obtaining ACZ-induced images in the MSD method is not identical to the procedure in the SD method. With our software program for rCBF quantification, the resting rCBF values determined by the MSD method were closely correlated with the values measured by the SD method (r=0.94), and there was also a good correlation between the ACZ-induced rCBF values obtained by the MSD method and by the SD method (r=0.81). The increase in rCBF under ACZ stress was estimated to be approximately 26% by the SD method and 38% by the MSD method, suggesting that the MSD method tends to overestimate the increase in rCBF under ACZ stress in comparison with the SD method, but the variability of the rCBF values at rest and during ACZ stress analyzed by the MSD method was smaller than the variability with the SD method. Further clinical studies are required to validate our rCBF quantification analysis program for the MSD method. (author)

  4. Rapid, Sensitive, and Specific Lateral-Flow Immunochromatographic Device To Measure Anti-Anthrax Protective Antigen Immunoglobulin G in Serum and Whole Blood

    Science.gov (United States)

    Biagini, Raymond E.; Sammons, Deborah L.; Smith, Jerome P.; MacKenzie, Barbara A.; Striley, Cynthia A. F.; Snawder, John E.; Robertson, Shirley A.; Quinn, Conrad P.

    2006-01-01

    Evidence from animals suggests that anti-anthrax protective antigen (PA) immunoglobulin G (IgG) from vaccination with anthrax vaccine adsorbed (AVA) is protective against Bacillus anthracis infection. Measurement of anti-PA IgG in human sera can be performed using either enzyme-linked immunosorbent assay or fluorescent covalent microsphere immunoassay (ELISA) (R. E. Biagini, D. L. Sammons, J. P. Smith, B. A. MacKenzie, C. A. Striley, V. Semenova, E. Steward-Clark, K. Stamey, A. E. Freeman, C. P. Quinn, and J. E. Snawder, Clin. Diagn. Lab. Immunol. 11:50-55, 2004). Both these methods are laboratory based. We describe the development of a rapid lateral-flow immunochromatographic assay (LFIA) test kit for the measurement of anti-PA IgG in serum or whole-blood samples (30-μl samples) using colloidal gold nanoparticles as the detection reagent and an internal control. Using sera from 19 anthrax AVA vaccinees (anti-PA IgG range, 2.4 to 340 μg/ml) and 10 controls and PA-supplemented whole-blood samples, we demonstrated that the LFIA had a sensitivity of approximately 3 μg/ml anti-PA IgG in serum and ∼14 μg/ml anti-PA IgG in whole blood. Preabsorption of sera with PA yielded negative anti-PA LFIAs. The diagnostic sensitivity and specificity of the assay were 100% using ELISA-measured anti-PA IgG as the standard. This kit has utility in determining anti-PA antibody reactivity in the sera of individuals vaccinated with AVA or individuals with clinical anthrax. PMID:16682473

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

    DEFF Research Database (Denmark)

    Lubberink, Mark; Ebrahimi, M; Harms, Hans

    Aim: Motion-induced PET-CT misalignment artifacts are common in myocardial blood flow (MBF) measurements with 82Rb and 13N-ammonia. For 15O-water, MBF is based on the clearance rate rather than uptake of the tracer. The clearance rate is determined by the shape of the time-activity curve, not its......-CT misalignment on MBF, transmural MBF (MBFt), perfusable tissue fraction (PTF), cardiac output (CO), stroke volume (SV) and left-ventricular ejection fraction (LVEF) based on dynamic 15O-water scans. Methods: 10 patients underwent 6 min PET scans after injection of 400 MBq 15O-water at rest and during adenosine...

  6. Analysis of music-brain interaction with simultaneous measurement of regional cerebral blood flow and electroencephalogram beta rhythm in human subjects.

    Science.gov (United States)

    Nakamura, S; Sadato, N; Oohashi, T; Nishina, E; Fuwamoto, Y; Yonekura, Y

    1999-11-19

    To elucidate the neural substrates of the receptive aspect of music, we measured regional cerebral blood flow (rCBF) with positron emission tomography (PET) and simultaneously recorded the electroencephalogram (EEG) in eight normal volunteers. Compared with the rest condition, listening to music caused a significant increase in EEG beta power spectrum (13-30 Hz) averaged over the posterior two third of the scalp. The averaged beta power spectrum was positively correlated with rCBF in the premotor cortex and adjacent prefrontal cortices bilaterally, the anterior portion of the precuneus and the anterior cingulate cortex in both the rest and the music conditions. Listening to music newly recruited the posterior portion of the precuneus bilaterally. This may reflect the interaction of the music with the cognitive processes, such as music-evoked memory recall or visual imagery.

  7. Regulation of blood flow by prostaglandins

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Risum, N

    2004-01-01

    adaptation of connective tissues e.g. tendon. This review covers the role of PG for mediating tissue blood flow at rest and during increases in metabolic demand such as exercise and reactive hyperaemia. There is strong evidence that PGs contribute to elevate blood flow at rest and during reactive hyperaemia...... in a variety of tissues. Their role for regulating the large increases in muscle blood flow during exercise is less clear which may be explained by redundant mechanisms. Several interactions are known to exist between specific vasodilator substances, and therefore PGs can act in synergy with other substances...... and contribute to functional hyperaemia. Furthermore, there is evidence for differential, tissue-specific influences of PGs where their influence on blood flow during exercise may be profound....

  8. Blood flow patterns underlie developmental heart defects.

    Science.gov (United States)

    Midgett, Madeline; Thornburg, Kent; Rugonyi, Sandra

    2017-03-01

    Although cardiac malformations at birth are typically associated with genetic anomalies, blood flow dynamics also play a crucial role in heart formation. However, the relationship between blood flow patterns in the early embryo and later cardiovascular malformation has not been determined. We used the chicken embryo model to quantify the extent to which anomalous blood flow patterns predict cardiac defects that resemble those in humans and found that restricting either the inflow to the heart or the outflow led to reproducible abnormalities with a dose-response type relationship between blood flow stimuli and the expression of cardiac phenotypes. Constricting the outflow tract by 10-35% led predominantly to ventricular septal defects, whereas constricting by 35-60% most often led to double outlet right ventricle. Ligation of the vitelline vein caused mostly pharyngeal arch artery malformations. We show that both cardiac inflow reduction and graded outflow constriction strongly influence the development of specific and persistent abnormal cardiac structure and function. Moreover, the hemodynamic-associated cardiac defects recapitulate those caused by genetic disorders. Thus our data demonstrate the importance of investigating embryonic blood flow conditions to understand the root causes of congenital heart disease as a prerequisite to future prevention and treatment. NEW & NOTEWORTHY Congenital heart defects result from genetic anomalies, teratogen exposure, and altered blood flow during embryonic development. We show here a novel "dose-response" type relationship between the level of blood flow alteration and manifestation of specific cardiac phenotypes. We speculate that abnormal blood flow may frequently underlie congenital heart defects. Copyright © 2017 the American Physiological Society.

  9. Nutrient and nonnutrient renal blood flow

    International Nuclear Information System (INIS)

    Young, J.S.; Passmore, J.C.; Hartupee, D.A.; Baker, C.H.

    1990-01-01

    The role of prostaglandins in the distribution of total renal blood flow (TRBF) between nutrient and nonnutrient compartments was investigated in anesthetized mongrel dogs. Renal blood flow distribution was assessed by the xenon 133 freeze-dissection technique and by rubidium 86 extraction after ibuprofen treatment. Ibuprofen (13 mg/kg) significantly decreased TRBF by 16.3% +/- 1.2% (mean +/- SEM electromagnetic flow probe; p less than 0.005), but did not alter blood flows to the outer cortex (3.7 vs 4.3 ml/min per gram), the inner cortex (2.6 vs 2.7 ml/min per gram), and the other medulla (1.5 vs 1.5 ml/min per gram), which suggests a decrease in nonnutrient flow. In a separate group of animals the effect of reduced blood flow on the nutrient and nonnutrient components was determined by mechanically reducing renal arterial blood flow by 48%. Unlike the ibuprofen group, nutrient blood flows were proportionally reduced with the mechanical decrease in TRBF in the outer cortex (1.9 ml/min per gram, p less than 0.05), the inner cortex (1.4 ml/min per gram, p less than 0.05), and the outer medulla (0.8 ml/min per gram, p less than 0.01). These results indicate no shift between nutrient and nonnutrient compartments. Nutrient and nonnutrient renal blood flows of the left kidney were also determined by 86Rb extraction. After ibuprofen treatment, nonextracted 86Rb decreased to 12.1% from the control value of 15.6% (p less than 0.05). Mechanical reduction of TRBF did not significantly decrease the proportion of unextracted 86Rb (18.7%)

  10. A broadband continuous-wave multichannel near-infrared system for measuring regional cerebral blood flow and oxygen consumption in newborn piglets

    Science.gov (United States)

    Diop, Mamadou; Elliott, Jonathan T.; Tichauer, Kenneth M.; Lee, Ting-Yim; St. Lawrence, Keith

    2009-05-01

    Near-infrared spectroscopy (NIRS) is a promising technique for assessing brain function in newborns, particularly due to its portability and sensitivity to cerebral hemodynamics and oxygenation. Methods for measuring cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) have been developed based on broadband continuous-wave NIRS. However, broadband NIRS apparatus typically have only one detection channel, which limits their applicability to measuring regional CBF and CMRO2. In this study, a relatively simple multiplexing approach based on electronically controlled mechanical shutters is proposed to expand the detection capabilities from one to eight channels. The tradeoff is an increase in the sampling interval; however, this has negligible effects on CBF measurements for intervals less than or equal to 1 s. The ability of the system to detect focal brain injury was demonstrated in piglets by injecting endothelin-1 (ET-1) into the cerebral cortex. For validation, CBF was independently measured by computed tomography (CT) perfusion. The average reduction in CBF from the source-detector pair that interrogated the injured region was 51%±9%, which was in good agreement with the CBF reduction measured by CT perfusion (55%±5%). No significant changes in regional CMRO2 were observed. The average regional differential pathlength prior to ET-1 injection was 8.4±0.2 cm (range of 7.1-9.6 cm) and did not significantly change after the injury.

  11. Repeated measurements of cerebral blood flow in the left superior temporal gyrus reveal tonic hyperactivity in patients with auditory verbal hallucinations: A possible trait marker

    Directory of Open Access Journals (Sweden)

    Philipp eHoman

    2013-06-01

    Full Text Available Background: The left superior temporal gyrus (STG has been suggested to play a key role in auditory verbal hallucinations in patients with schizophrenia. Methods: Eleven medicated subjects with schizophrenia and medication-resistant auditory verbal hallucinations and 19 healthy controls underwent perfusion magnetic resonance imaging with arterial spin labeling. Three additional repeated measurements were conducted in the patients. Patients underwent a treatment with transcranial magnetic stimulation (TMS between the first 2 measurements. The main outcome measure was the pooled cerebral blood flow (CBF, which consisted of the regional CBF measurement in the left superior temporal gyrus (STG and the global CBF measurement in the whole brain.Results: Regional CBF in the left STG in patients was significantly higher compared to controls (p < 0.0001 and to the global CBF in patients (p < 0.004 at baseline. Regional CBF in the left STG remained significantly increased compared to the global CBF in patients across time (p < 0.0007, and it remained increased in patients after TMS compared to the baseline CBF in controls (p < 0.0001. After TMS, PANSS (p = 0.003 and PSYRATS (p = 0.01 scores decreased significantly in patients.Conclusions: This study demonstrated tonically increased regional CBF in the left STG in patients with schizophrenia and auditory hallucinations despite a decrease in symptoms after TMS. These findings were consistent with what has previously been termed a trait marker of auditory verbal hallucinations in schizophrenia.

  12. Modeling Blood Flow in the Aorta.

    Science.gov (United States)

    McConnell, Colin J.; Carmichael, Jonathan B.; DeMont, M. Edwin

    1997-01-01

    Presents an exercise to demonstrate two fundamental concepts of fluid mechanics: the Reynolds number and the Principle of Continuity. The exercise demonstrates flow in a major blood vessel, such as the aorta, with and without a stenosis. Students observe the transition from laminar to turbulent flow as well as downstream persistence of turbulence.…

  13. Collateral sources of costal and crural diaphragmatic blood flow

    International Nuclear Information System (INIS)

    Lockhat, D.; Magder, S.; Roussos, C.

    1985-01-01

    We measured the contribution of aortic, internal mammary, and intercostal arteries to the blood flow to the costal and crural segments of the diaphragm and other respiratory muscles in seven dogs breathing against a fixed inspiratory elastic load. We used radiolabeled microspheres to measure the blood flow with control circulation, occlusion of the aorta distal to the left subclavian artery, combined occlusion of the aorta and both internal mammary arteries, and occlusion of internal mammary arteries alone. With occlusion of the aorta distal to the left subclavian artery, blood flow to the crural diaphragm decreased from 40.3 to 23.5 ml . min-1 X 100 g-1, whereas costal flow did not change significantly (from 41.7 to 38.1 ml . min-1 . 100 g-1). Blood flows to the sternomastoid and scalene muscles (above the occlusion) increased by 200 and 340%, respectively, whereas flows to the other respiratory muscles did not change significantly. Blood flows to organs above the occlusion either remained unchanged or increased, whereas flows to those below the occlusion all decreased. When the internal mammary artery was also occluded, flows to the crural segment decreased further to 12.1 and costal flow decreased to 20.4 ml X min-1 X 100 g-1. Internal mammary arterial occlusion alone in two dogs had no effect on diaphragmatic flow. In conclusion, intercostal collateral vessels are capable of supplying a significant proportion of blood flow to both segments of the diaphragm but the costal segment is better served than the crural segment

  14. Blood flow and clearance in tendons. Studies with dogs.

    Science.gov (United States)

    Hooper, G; Davies, R; Tothill, P

    1984-05-01

    Blood flow in intact tendons in dogs was measured using 57Co-labelled microspheres and compared with the simultaneous clearance of a diffusible radionuclide, 85Sr, by the same tendons. Clearance was significantly greater than flow in all tendons, indicating that diffusion from surrounding tissues may be important in the nutrition of normal tendons.

  15. Stochastic modeling for magnetic resonance quantification of myocardial blood flow

    Science.gov (United States)

    Seethamraju, Ravi T.; Muehling, Olaf; Panse, Prasad M.; Wilke, Norbert M.; Jerosch-Herold, Michael

    2000-10-01

    Quantification of myocardial blood flow is useful for determining the functional severity of coronary artery lesions. With advances in MR imaging it has become possible to assess myocardial perfusion and blood flow in a non-invasive manner by rapid serial imaging following injection of contrast agent. To date most approaches reported in the literature relied mostly on deriving relative indices of myocardial perfusion directly from the measured signal intensity curves. The central volume principle on the other hand states that it is possible to derive absolute myocardial blood flow from the tissue impulse response. Because of the sensitivity involved in deconvolution due to noise in measured data, conventional methods are sub-optimal, hence, we propose to use stochastic time series modeling techniques like ARMA to obtain a robust impulse response estimate. It is shown that these methods when applied for the optical estimation of the transfer function give accurate estimates of myocardial blood flow. The most significant advantage of this approach, compared with compartmental tracer kinetic models, is the use of a minimum set of prior assumptions on data. The bottleneck in assessing myocardial blood flow, does not lie in the MRI acquisition, but rather in the effort or time for post processing. It is anticipated that the very limited requirements for user input and interaction will be of significant advantage for the clinical application of these methods. The proposed methods are validated by comparison with mean blood flow measurements obtained from radio-isotope labeled microspheres.

  16. Reliability of laser Doppler, near-infrared spectroscopy and Doppler ultrasound for peripheral blood flow measurements during and after exercise in the heat.

    Science.gov (United States)

    Choo, Hui C; Nosaka, Kazunori; Peiffer, Jeremiah J; Ihsan, Mohammed; Yeo, Chow C; Abbiss, Chris R

    2017-09-01

    This study examined the test-retest reliability of near-infrared spectroscopy (NIRS), laser Doppler flowmetry (LDF) and Doppler ultrasound to assess exercise-induced haemodynamics. Nine men completed two identical trials consisting of 25-min submaximal cycling at first ventilatory threshold followed by repeated 30-s bouts of high-intensity (90% of peak power) cycling in 32.8 ± 0.4°C and 32 ± 5% relative humidity (RH). NIRS (tissue oxygenation index [TOI] and total haemoglobin [tHb]) and LDF (perfusion units [PU]) signals were monitored continuously during exercise, and leg blood flow was assessed by Doppler ultrasound at baseline and after exercise. Cutaneous vascular conductance (CVC; PU/mean arterial pressure (MAP)) was expressed as the percentage change from baseline (%CVC BL ). Coefficients of variation (CVs) as indicators of absolute reliability were 18.7-28.4%, 20.2-33.1%, 42.5-59.8%, 7.8-12.4% and 22.2-30.3% for PU, CVC, %CVC BL , TOI and tHb, respectively. CVs for these variables improved as exercise continued beyond 10 min. CVs for baseline and post-exercise leg blood flow were 17.8% and 10.5%, respectively. CVs for PU, tHb (r 2  = 0.062) and TOI (r 2  = 0.002) were not correlated (P > 0.05). Most variables demonstrated CVs lower than the expected changes (35%) induced by training or heat stress; however, minimum of 10 min exercise is recommended for more reliable measurements.

  17. Color Doppler measurement of blood flow in the inferior thyroid artery in patients with autoimmune thyroid diseases

    International Nuclear Information System (INIS)

    Caruso, Giuseppe; Attard, Marco; Caronia, Aurelio; Lagalla, Roberto

    2000-01-01

    Purpose: The aim of the study is to find out whether the measurement of peak systolic velocity in the inferior thyroid artery (ITA) is a valuable parameter to differentiate autoimmune thyroid diseases (hyper-, normo- or hypofunctional) and to evaluate the efficacy of medical treatment. Material and methods: The ITA of 31 patients (eight with Graves' disease, 23 with subclinical hypothyroidism) was examined with color Doppler and pulsed Doppler. The final diagnosis was obtained by citology and by hormonal and antibodies assays. The patients were monitorized by ultrasound for a period of 8 months. Results: In all the patients with Graves' disease the peak systolic velocity was always over 150 cm/s, while in other autoimmune thyroiditis the peak systolic velocity was within the normal range, and never exceeding 65 cm/s. In the first group, the measurement taken in the ITA showed also the efficacy of the pharmacological treatment earlier and more reliably than the color Doppler pattern obtained in the parenchyma. Conclusions: The color Doppler measurement of the ITA seems to be a promising technique with low-cost and easy approach. In our experience, the color Doppler of the ITA could have a clinical role in the differential diagnosis of diffuse thyroid diseases and in the follow-up of the Graves' disease during medical treatment

  18. Cerebral blood flow variations in CNS lupus

    International Nuclear Information System (INIS)

    Kushner, M.J.; Tobin, M.; Fazekas, F.; Chawluk, J.; Jamieson, D.; Freundlich, B.; Grenell, S.; Freemen, L.; Reivich, M.

    1990-01-01

    We studied the patterns of cerebral blood flow (CBF), over time, in patients with systemic lupus erythematosus and varying neurologic manifestations including headache, stroke, psychosis, and encephalopathy. For 20 paired xenon-133 CBF measurements, CBF was normal during CNS remissions, regardless of the symptoms. CBF was significantly depressed during CNS exacerbations. The magnitude of change in CBF varied with the neurologic syndrome. CBF was least affected in patients with nonspecific symptoms such as headache or malaise, whereas patients with encephalopathy or psychosis exhibited the greatest reductions in CBF. In 1 patient with affective psychosis, without clinical or CT evidence of cerebral ischemia, serial SPECT studies showed resolution of multifocal cerebral perfusion defects which paralleled clinical recovery

  19. Cerebral blood flow variations in CNS lupus

    Energy Technology Data Exchange (ETDEWEB)

    Kushner, M.J.; Tobin, M.; Fazekas, F.; Chawluk, J.; Jamieson, D.; Freundlich, B.; Grenell, S.; Freemen, L.; Reivich, M. (Univ. of Pennsylvania Medical Center, Philadelphia (USA))

    1990-01-01

    We studied the patterns of cerebral blood flow (CBF), over time, in patients with systemic lupus erythematosus and varying neurologic manifestations including headache, stroke, psychosis, and encephalopathy. For 20 paired xenon-133 CBF measurements, CBF was normal during CNS remissions, regardless of the symptoms. CBF was significantly depressed during CNS exacerbations. The magnitude of change in CBF varied with the neurologic syndrome. CBF was least affected in patients with nonspecific symptoms such as headache or malaise, whereas patients with encephalopathy or psychosis exhibited the greatest reductions in CBF. In 1 patient with affective psychosis, without clinical or CT evidence of cerebral ischemia, serial SPECT studies showed resolution of multifocal cerebral perfusion defects which paralleled clinical recovery.

  20. Cerebral blood flow measurement in patients with impaired consciousness: usefulness of {sup 99m}Tc-HMPAO single-photon emission tomography in clinical practice

    Energy Technology Data Exchange (ETDEWEB)

    Chang Chia-Cheng; Kuwana, Nobumasa; Noji, Masato; Tanabe, Yutaka; Koike, Y. [Department of Neurosurgery, Yokohama Minami Kyosai Hospital, Yokohama (Japan); Ikegami, Tadashi [Department of Radiology, Yokohama Minami Kyosai Hospital, Yokohama (Japan)

    1998-09-01

    The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography ({sup 99m}Tc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using {sup 99m}Tc-HMPAO SPET is reliable in clinical evaluations. (orig.) With 3 tabs., 10 refs.

  1. Development of a new Xe-133 single dose multi-step method (SDMM) for muscle blood flow measurement using gamma camera

    International Nuclear Information System (INIS)

    Bunko, Hisashi; Seto, Mikito; Taki, Junichi

    1985-01-01

    In order to measure the muscle blood flow (MBF) during exercise (Ex), a new Xe-133 single dose multi-step method (SDMM) for leg MBF measurement before, during and after Ex using gamma camera was developped. Theoretically, if the activity of Xe-133 in the muscle immediately before and after Ex are known, then the mean MBF during Ex can be calculated. In SDMM, these activities are corrected through correction formula using time delays between end of data aquisition (DA) at rest (R1) and begining of the Ex (TAB), and between end of Ex and begining of the DA after Ex (R2) (TDA). Validity of the SDMM and MBF response on mild and heavy Ex were evaluated in 11 normal volunteers. Ex MBF calculated from 5 and 2.5 min DA (5 sec/frame) both at R1 and R2 were highly correlated (r=.996). Ex MBF by SDMM and direct(measurement by fixed leg exercise were also highly correlated (r=.999). Reproducibility of the R1 and Ex MBF were excellent (r=.999). The highest MBF was seen in GCM on miled walking Ex and in VLM on heavy squatting Ex. After miled Ex, MBF rapidly returned to normal. After heavy Ex, MBF remaind high in VLM In conclusion, SDMM is simple and accurate method for evaluation of dynamic MBF response according to exercise. SDMM is also applicable to the field of sports medicine. (author)

  2. Cerebral blood flow measurement in patients with impaired consciousness: usefulness of 99mTc-HMPAO single-photon emission tomography in clinical practice

    International Nuclear Information System (INIS)

    Chang Chia-Cheng; Kuwana, Nobumasa; Noji, Masato; Tanabe, Yutaka; Koike, Y.; Ikegami, Tadashi

    1998-01-01

    The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography ( 99m Tc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using 99m Tc-HMPAO SPET is reliable in clinical evaluations. (orig.)

  3. Magnetohydrodynamic Voltage Recorder for Comparing Peripheral Blood Flow.

    Science.gov (United States)

    Wu, Kevin J; Gregory, T Stan; Lastinger, Michael C; Murrow, Jonathan R; Tse, Zion Tsz Ho

    2017-10-01

    Blood flow is a clinical metric for monitoring of cardiovascular diseases but current measurements methods are costly or uncomfortable for patients. It was shown that the interaction of the magnetic field (B 0 ) during MRI and blood flow in the body, through the magnetohydrodynamic (MHD) effect, produce voltages (V MHD ) observable through intra-MRI electrocardiography (ECG), which are correlated with regional blood flow. This study shows the reproducibility of V MHD outside the MRI and its application in a portable flow monitoring device. To recreate this interaction outside the MRI, a static neodymium magnet (0.4T) was placed in between two electrodes to induce the V MHD in a single lead ECG measurement. V MHD was extracted, and integrated over to obtain a stroke volume metric. A smartphone-enabled device utilizing this interaction was developed in order to create a more accessible method of obtaining blood flow measurements. The portable device displayed a MHD using the 0.4T magnet. Exercise stress testing showed a V MHD increase of 23% in healthy subjects, with an 81% increase in the athlete. The study demonstrates a new device utilizing MHD interactions with body circulation to obtain blood flow metrics.

  4. DIGITAL BLOOD-FLOW IN COOLED AND CONTRALATERAL FINGER IN PATIENTS WITH RAYNAUD PHENOMENON - COMPARATIVE MEASUREMENTS BETWEEN PHOTOELECTRICAL PLETHYSMOGRAPHY AND LASER DOPPLER FLOWMETRY

    NARCIS (Netherlands)

    SUICHIES, HE; AARNOUDSE, JG; WOUDA, AA; JENTINK, HW; DEMUL, FFM; GREVE, J

    The effects of cooling of a hand on lateral and contralateral digital skin blood flow were investigated in 18 patients with primary or secondary Raynaud's phenomenon. The aim of the study was to compare photoelectrical plethsmography (PhEP) and laser Doppler flowmetry (LDF). PhEP and LDF were used

  5. Quantitative assessment of limb blood flow using Tc-99m labeled red blood cells

    International Nuclear Information System (INIS)

    Itoh, Kazuo; Shougase, Takashi; Kawamura, Naoyuki; Tsukamoto, Eriko; Nakada, Kunihiro; Sakuma, Makoto; Furudate, Masayori

    1987-01-01

    A quantitative assessment of limb blood flow using a non-diffusible radioindicator, Tc-99m labeled red blood cells, was reported. This was an application of venous occlusion plethysmography using radionuclide which was originally proposed by M. Fukuoka et al. The peripheral blood flow (mean ± s.e.) of 30 legs in a normal control group was 1.87 ± 0.08 ml/100 ml/min. In heart diseases (46 legs), it was 1.49 ± 0.13 ml/100 ml/min. The limb blood flow between a control group and heart diseases was statistically significant (p < 0.01) in the t-test. The peripheral blood flow at rest between diseased legs and normal legs in occlusive arterial disorders was also statistically significant (p < 0.01) in a paired t-test. RAVOP was done after the completion of objective studies such as radionuclide angiography or ventriculography. Technique and calculation of a blood flow were very easy and simple. RAVOP study which was originally proposed by Fukuoka et al. was reappraised to be hopeful for quantitative measurement of limb blood flow as a non-invasive technique using Tc-99m labeled red blood cells. (author)

  6. MEASUREMENT OF BLOOD FLOW IN ARTERIA MENINGEA MEDIA OF PATIENTS WITH FREQUENT EPISODIC TENSION-TYPE HEADACHE NOT ASSOCIATED WITH PERICRANIAL TENDERNESS

    Directory of Open Access Journals (Sweden)

    A.A. Skoromets

    2008-06-01

    Full Text Available Twenty seven patients with frequent episodic tension-type headache not associated with pericrania! tenderness (TTH aged from 18 to 69 years old were examined. Arteria meningea media (AMM and brachiocephalic arteries (BCA were examined by supersonic power Doppler scanning during the paroxysm of headache and without the paroxysm of headache. Results: Blood flow in AMM of patients with TTH was significantly different during the paroxysm of headache and without the paroxysm of headache (p<0.01. Blood flow in arteria carotid external did not change (p>0.05. The pattern of hypoperfusion in AMM was displayed in two groups during the paroxysm of headache. The increase of average blood velocity (TAmx in groups of patients with TTH in comparison with the control group.

  7. Continuous and simultaneous measurement of the tank-treading motion of red blood cells and the surrounding flow using translational confocal micro-particle image velocimetry (micro-PIV) with sub-micron resolution

    International Nuclear Information System (INIS)

    Oishi, M; Utsubo, K; Kinoshita, H; Fujii, T; Oshima, M

    2012-01-01

    In this study, a translational confocal micro-particle image velocimetry (PIV) system is introduced to measure the microscopic interaction between red blood cells (RBCs) and the surrounding flow. Since the macroscopic behavior of RBCs, such as the tank-treading motion, is closely related to the axial migration and other flow characteristics in arterioles, the measurement method must answer the conflicting demands of sub-micron resolution, continuous measurement and applicability for high-speed flow. In order to avoid loss of the measurement target, i.e. RBCs, from the narrow field of view during high-magnification measurement, the translation stage with the flow device moves in the direction opposite the direction of flow. The proposed system achieves the measurement of higher absolute velocities compared with a conventional confocal micro-PIV system without the drawbacks derived from stage vibration. In addition, we have applied a multicolor separation unit, which can measure different phases simultaneously using different fluorescent particles, in order to clarify the interaction between RBCs and the surrounding flow. Based on our measurements, the tank-treading motion of RBCs depends on the shear stress gradient of the surrounding flow. Although, the relationship between the tank-treading frequency and the shear rate of the surrounding flow is of the same order as in the previous uniform shear rate experiments, our results reveal the remarkable behavior of the non-uniform membrane velocities and lateral velocity component of flow around the RBCs. (paper)

  8. In silico particle margination in blood flow

    OpenAIRE

    Müller, Kathrin

    2015-01-01

    A profound knowledge of margination, the migration of blood components to the vessel wall in blood flow, is required in order to understand the genesis of various diseases, as e.g., cardiovascular diseases or bleeding disorders. Margination of particles is a pre-condition for potential adhesion. Adhesion to the vessel wall is required for platelets, the protein von Willebrand factor (VWF), but also for drug and imaging agent carriers in order to perform their particular tasks. In the haemosta...

  9. Arterial secondary blood flow patterns visualized with vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Hansen, Jens Munk

    2011-01-01

    and velocity magnitudes the blood flow patterns were visualised with streamlines in Matlab (Mathworks, Natick, MA, USA). The rotational flow was quantified by the angular frequency for each cardiac cycle, and the mean rotational frequencies and standard deviations were calculated for the abdominal aorta f-1......This study presents the first quantification and visualisation of secondary flow patterns with vector flow ultrasound. The first commercial implementation of the vector flow method Transverse Oscillation was used to obtain in-vivo, 2D vector fields in real-time. The hypothesis of this study...... was that the rotational direction is constant within each artery. Three data sets of 10 seconds were obtained from three main arteries in healthy volunteers. For each data set the rotational flow patterns were identified during the diastole. Each data set contains a 2D vector field over time and with the vector angles...

  10. Measurement of cerebral blood flow using bolus inhalation of C15O2 and positron emission tomography: description of the method and its comparison with the C15O2 continuous inhalation method

    International Nuclear Information System (INIS)

    Kanno, I.; Lammertsma, A.A.; Heather, J.D.; Gibbs, J.M.; Rhodes, C.G.; Clark, J.C.; Jones, T.

    1984-01-01

    This article describes a rapid method for the regional measurement of cerebral blood flow using a single breath of C 15 O 2 and positron emission tomography. The technique is based on the bolus distribution principle and utilises a reference table for the calculation of flow. Seven subjects were studied using both this method and the C 15 O 2 continuous inhalation steady-state technique. The single-breath method gave flow values 20% higher than those obtained using the steady-state method. A simulation study was performed in an attempt to define the reasons for the difference between the two techniques. Estimations were made of identified sources of error in the measurement of regional cerebral blood flow using the single-breath technique and compared with results from a similar study previously described for the steady-state technique. However, further comparative studies will be necessary to satisfactorily explain the difference between both techniques

  11. Simultaneous PET/MR imaging of the brain: feasibility of cerebral blood flow measurements with FAIR-TrueFISP arterial spin labeling MRI.

    Science.gov (United States)

    Stegger, Lars; Martirosian, Petros; Schwenzer, Nina; Bisdas, Sotirios; Kolb, Armin; Pfannenberg, Christina; Claussen, Claus D; Pichler, Bernd; Schick, Fritz; Boss, Andreas

    2012-11-01

    Hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) with simultaneous data acquisition promises a comprehensive evaluation of cerebral pathophysiology on a molecular, anatomical, and functional level. Considering the necessary changes to the MR scanner design the feasibility of arterial spin labeling (ASL) is unclear. To evaluate whether cerebral blood flow imaging with ASL is feasible using a prototype PET/MRI device. ASL imaging of the brain with Flow-sensitive Alternating Inversion Recovery (FAIR) spin preparation and true fast imaging in steady precession (TrueFISP) data readout was performed in eight healthy volunteers sequentially on a prototype PET/MRI and a stand-alone MR scanner with 128 × 128 and 192 × 192 matrix sizes. Cerebral blood flow values for gray matter, signal-to-noise and contrast-to-noise ratios, and relative signal change were compared. Additionally, the feasibility of ASL as part of a clinical hybrid PET/MRI protocol was demonstrated in five patients with intracerebral tumors. Blood flow maps showed good delineation of gray and white matter with no discernible artifacts. The mean blood flow values of the eight volunteers on the PET/MR system were 51 ± 9 and 51 ± 7 mL/100 g/min for the 128 × 128 and 192 × 192 matrices (stand-alone MR, 57 ± 2 and 55 ± 5, not significant). The value for signal-to-noise (SNR) was significantly higher for the PET/MRI system using the 192 × 192 matrix size (P change (δS) was significantly lower for the 192 × 192 matrix size (P = 0.02). ASL imaging as part of a clinical hybrid PET/MRI protocol could successfully be accomplished in all patients in diagnostic image quality. ASL brain imaging is feasible with a prototype hybrid PET/MRI scanner, thus adding to the value of this novel imaging technique.

  12. Contribution of frontal cerebral blood flow measured by (99m)Tc-Bicisate spect and executive function deficits to predicting treatment outcome in alcohol-dependent patients.

    Science.gov (United States)

    Noël, Xavier; Sferrazza, Rita; Van Der Linden, Martial; Paternot, Jacques; Verhas, Michel; Hanak, Catherine; Pelc, Isidore; Verbanck, Paul

    2002-01-01

    To determine whether inhibition and working memory deficits, and reduced regional cerebral blood flow (rCBF) (previously shown to be related), measured at the end of a detoxification programme, predict alcoholic relapse 2 months later. Twenty uncomplicated alcoholic inpatients were investigated at the end of detoxification, at least 7 days since the last dose of diazepam, and a mean of 18.8 days since the last drink. Their performance was assessed on the inhibition (Hayling) test, working memory (Alpha-span task), episodic memory (California Verbal Learning Test) and abstract reasoning (Progressive Matrices). Frontal CBF was assessed at the same time with a semiquantitative (99m)Tc-Bicisate SPECT procedure. Patients were contacted 2 months later. Patients who abstained (n = 9) did not differ from those who relapsed (n = 11) on age, gender, smoking, duration of alcohol misuse, number of previous detoxifications, amount of ethanol consumed the month prior to admission to the detoxification programme, state anxiety, trait anxiety, or depression. Relapsed subjects had shown a lower uptake of (99m)Tc-Bicisate in the bilateral medial frontal gyrus (n = 9; mean ratio +/- SD = 0.69 +/- 0.006) than abstainers (n = 11; 0.85 +/- 0.19), and poorer performance on the Alpha-span task and the Hayling test. The other tests were not different. Inhibition and working memory deficits, associated with low levels of CBF in the medial frontal gyrus, are related to the difficulty of maintaining short-term abstinence from alcohol.

  13. Quantification of cerebral blood flow via Duplex sonography

    International Nuclear Information System (INIS)

    Vogl, G.; Pohl, P.; Willeit, J.; Aichner, F.

    1987-01-01

    An attempt was made to measure quantitatively the total cerebral blood flow by means of Duplex sonography. In a group of healthy young subjects a median value for total cerebral blood flow was obtained amounting to 469 ml/min ± 30%, repeat measurements yielded a maximum deviation of ± 11%. In three patients the values obtained after severe apoplectic insult due to occlusion of the internal carotid artery were definitely below the value of the group of healthy subjects, whereas the value for the total blood flow was in the upper range of normal values in a patient with occlusion of the a. cerebri media. Comparative measurements of the regional cerebral blood flow with xenon 13 yielded in those patients with occlusion of the internal carotid artery a markedly reduced mean flow and in the patient with occlusion of the a. cerebri media a less markedly reduced mean flow. Regionally reduced perfusion was seen in all the four patients in the range of the clinically and computer tomographically well-known ischaemia zone. Thanks to the simplicity of this sonographic examination method it could be a useful decision parameter in determining the indication for a reconstruction of the carotid artery, especially in asymptotic patients. (orig.) [de

  14. Disparity in regional cerebral blood flow during electrically induced seizure

    DEFF Research Database (Denmark)

    Sestoft, D; Meden, P; Hemmingsen, R

    1993-01-01

    This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized on electroencepha......This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized...

  15. Cerebral blood flow measured by arterial-spin labeling MRI: A useful biomarker for characterization of minimal hepatic encephalopathy in patients with cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Gang [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, 210016 (China); Zhang, Long Jiang, E-mail: kevinzhlj@163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); Zhong, Jianhui [Department of Imaging Sciences, University of Rochester School of Medicine and Dentistry, Box648, 601 Elmwood Avenue, Rochester, NY 14642-8648 (United States); Wang, Ze [Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, 3900 Chestnut St., Philadelphia, PA 19104 (United States); Qi, Rongfeng; Shi, Donghong [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); Lu, Guang Ming, E-mail: cjr.luguangming@vip.163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China)

    2013-11-01

    Purpose: To investigate the role of arterial-spin labeling (ASL) MRI to non-invasively characterize the patterns of cerebral blood flow (CBF) changes in cirrhotic patients and to assess the potential of ASL MRI to characterize minimal hepatic encephalopathy (MHE). Materials and methods: This study was approved by the local ethics committee, and written informed consent was obtained from all participants. Thirty six cirrhosis patients without overt hepatic encephalopathy (16 MHE patients and 20 non hepatic encephalopathy (non-HE) patients) and 25 controls underwent ASL MRI, and CBF was measured for each subject. One-way ANOCOVA test with age and gender as covariences was used to compare CBF difference among three groups, and post hoc analysis was performed between each two groups. Region-based correlation analysis was applied between Child–Pugh score, venous blood ammonia level, neuropsychological tests and CBF values in cirrhosis patients. Receiver operator characteristic (ROC) analysis was used for assessing CBF measurements in ASL MRI to differentiate MHE from non-HE patients. Results: The gray matter CBF of MHE patients (71.09 ± 11.88 mL min{sup −1} 100 g{sup −1}) was significantly higher than that of non-HE patients (55.28 ± 12.30 mL min{sup −1} 100 g{sup −1}, P < 0.01) and controls (52.09 ± 9.27 mL min{sup −1} 100 g{sup −1}, P < 0.001). Voxel-wise ANOCOVA results showed that CBFs were significantly different among three groups in multiple gray matter areas (P < 0.05, Bonferroni corrected). Post hoc comparisons showed that CBF of these brain regions was increased in MHE patients compared with controls and non-HE patients (P < 0.05, Bonferroni corrected). CBF of the right putamen was of the highest sensitivity (93.8%) and moderate specificity (75.0%) for characterization of MHE when using the cutoff value of 50.57 mL min{sup −1} 100 g{sup −1}. CBFs in the bilateral median cingulate gyri, left supramarginal gyrus, right angular gyrus, right

  16. Frequency encoding in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, D.J.; Sosnovtseva, Olga; Pavlov, A.N.

    2005-01-01

    With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation of ...

  17. Endoscopic laser Doppler flowmetry in evaluation of human gastric blood flow

    International Nuclear Information System (INIS)

    Lunde, O.C.

    1988-01-01

    The aims of the present study were to evaluate laser Doppler flowmetry (LDF) for endoscopic mesasurement of gastric blood flow. The study gave the following results: LDF is a reliable method for continuous measurement of gastrointestinal blood perfusion. This technique can be used endoscopically for measurement of gastric blood flow in conscious man. By means of endoscopic technique, relative blood flow changes can be measured in all parts of the stomach. The recorded blood flow values usually represent blood perfusion in all layers in the gastric wall. A slight contact pressure between the measuring probe and the mucosa is necessary to obtain stable recordings. To heavy pressure provokes reduction of flow values. Angulation of the probe and moderate air insufflation do not interfere with a constant flow level. Endoscopic measurements should be performed with a recording band-width of 4 kHz, since this frequency limit reduces the disturbing signals. Within the range of flow levels recorded in patients and healthy subjects, relative blood flow changes are measured with this band-width. Endoscopic LDF is safe and easy to handle. However, peristalsis and uneasy patients may sometime provoke disturbances which render blood flow measurements impossible. Endoscopic LDF is suitable for clinical studies such as investigation of the effect of drugs on gastric blood flow and examination of local blood flow in patients with gastric diseases

  18. Endoscopic laser Doppler flowmetry in evaluation of human gastric blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Lunde, O.C. (Aker Sykehus, Oslo (Norway))

    1988-12-01

    The aims of the present study were to evaluate laser Doppler flowmetry (LDF) for endoscopic mesasurement of gastric blood flow. The study gave the following results: LDF is a reliable method for continuous measurement of gastrointestinal blood perfusion. This technique can be used endoscopically for measurement of gastric blood flow in conscious man. By means of endoscopic technique, relative blood flow changes can be measured in all parts of the stomach. The recorded blood flow values usually represent blood perfusion in all layers in the gastric wall. A slight contact pressure between the measuring probe and the mucosa is necessary to obtain stable recordings. To heavy pressure provokes reduction of flow values. Angulation of the probe and moderate air insufflation do not interfere with a constant flow level. Endoscopic measurements should be performed with a recording band-width of 4 kHz, since this frequency limit reduces the disturbing signals. Within the range of flow levels recorded in patients and healthy subjects, relative blood flow changes are measured with this band-width. Endoscopic LDF is safe and easy to handle. However, peristalsis and uneasy patients may sometime provoke disturbances which render blood flow measurements impossible. Endoscopic LDF is suitable for clinical studies such as investigation of the effect of drugs on gastric blood flow and examination of local blood flow in patients with gastric diseases. 64 refs.

  19. Spatial Temporal Image Correlation Spectroscopy (STICS) for Flow Analysis with Application for Blood Flow Mapping (abstract)

    Science.gov (United States)

    Rossow, Molly; Mantulin, William M.; Gratton, Enrico

    2009-04-01

    It is important for surgeons to be able to measure blood flow in exposed arterioles during surgery. We report our progress in the development of an optical technique that will measure blood flow in surgically exposed blood vessels and enable previously difficult measurements. By monitoring optical fluctuations, the optical technique, based on Spatial Temporal Image Correlation (STICS), will directly measure the velocity of micron-scale particles-such as red blood cells. It will complement existing technology and provide qualitative measurements that were not previously possible. It relies on the concept that blood, when viewed on a small enough scale, is an inhomogeneous substance. Individual blood cells passing between a near-infrared light source and a detector will cause fluctuations in the transmitted optical signal. The speed, direction, and flow pattern of blood cells can be determined from these optical fluctuations. We present a series of computer simulations and experiments on phantom and animal systems to test this technique's ability to map complex flow patterns.

  20. Spatial Temporal Image Correlation Spectroscopy (STICS) for Flow Analysis with Application for Blood Flow Mapping

    International Nuclear Information System (INIS)

    Rossow, Molly; Gratton, Enrico; Mantulin, William M.

    2009-01-01

    It is important for surgeons to be able to measure blood flow in exposed arterioles during surgery. We report our progress in the development of an optical technique that will measure blood flow in surgically exposed blood vessels and enable previously difficult measurements. By monitoring optical fluctuations, the optical technique, based on Spatial Temporal Image Correlation (STICS), will directly measure the velocity of micron-scale particles--such as red blood cells. It will complement existing technology and provide qualitative measurements that were not previously possible. It relies on the concept that blood, when viewed on a small enough scale, is an inhomogeneous substance. Individual blood cells passing between a near-infrared light source and a detector will cause fluctuations in the transmitted optical signal. The speed, direction, and flow pattern of blood cells can be determined from these optical fluctuations. We present a series of computer simulations and experiments on phantom and animal systems to test this technique's ability to map complex flow patterns.

  1. Effects of a second heating on blood flow in tumors

    International Nuclear Information System (INIS)

    Song, C.W.; Chelstrom, L.M.; Sung, J.H.

    1990-01-01

    The blood flow in RIF-1 tumors of C3H mice, as measured with the 86Rb uptake method, declined markedly after a single heating at 43.5 degrees C or 44.5 degrees C for 1 h. However, preheating at 42.5 degrees C for 1 h significantly lessened the decrease in tumor blood flow caused by subsequent heating at 43.5 degrees C or 44.5 degrees C for 1 h. Such an influence of preheating on the effect of reheating in decreasing the tumor blood flow was significant as early as 6 h after the preheating, peaked at 36 h, and then decayed the following 2-3 days. In fact, a reheating at 43.5 degrees C for 1 h applied 36 h after a preheating at 42.5 degrees C for 1 h resulted in an increase rather than a decrease in blood flow. The cause of such a profound impact of preheating on the effect of reheating on the blood flow is unclear. However, circumstantial evidence including the histopathological appearance of tumors suggests that thermotolerance is induced in the blood vessels of the tumor as a result of preheating

  2. Measurement of blood flow in the superior sagittal sinus in healthy volunteers, and in patients with normal pressure hydrocephalus and idiopathic intracranial hypertension with phase-contrast cine MR imaging

    DEFF Research Database (Denmark)

    Gideon, P; Thomsen, C; Gjerris, F

    1996-01-01

    PURPOSE: To measure blood flow and velocity in the superior sagittal ++sinus. MATERIAL AND METHODS: MR velocity mapping was used to examine 14 healthy volunteers, 15 patients with normal pressure hydrocephalus (NPH), 3 patients with high pressure hydrocephalus (HPH), and 11 patients with idiopath...

  3. Coronary blood flow during cardiopulmonary resuscitation in swine

    International Nuclear Information System (INIS)

    Bellamy, R.F.; DeGuzman, L.R.; Pedersen, D.C.

    1984-01-01

    Recent papers have raised doubt as to the magnitude of coronary blood flow during closed-chest cardiopulmonary resuscitation. We will describe experiments that concern the methods of coronary flow measurement during cardiopulmonary resuscitation. Nine anesthetized swine were instrumented to allow simultaneous measurements of coronary blood flow by both electromagnetic cuff flow probes and by the radiomicrosphere technique. Cardiac arrest was caused by electrical fibrillation and closed-chest massage was performed by a Thumper (Dixie Medical Inc., Houston). The chest was compressed transversely at a rate of 66 strokes/min. Compression occupied one-half of the massage cycle. Three different Thumper piston strokes were studied: 1.5, 2, and 2.5 inches. Mean aortic pressure and total systemic blood flow measured by the radiomicrosphere technique increased as Thumper piston stroke was lengthened (mean +/- SD): 1.5 inch stroke, 23 +/- 4 mm Hg, 525 +/- 195 ml/min; 2 inch stroke, 33 +/- 5 mm Hg, 692 +/- 202 ml/min; 2.5 inch stroke, 40 +/- 6 mm Hg, 817 +/- 321 ml/min. Both methods of coronary flow measurement (electromagnetic [EMF] and radiomicrosphere [RMS]) gave similar results in technically successful preparations (data expressed as percent prearrest flow mean +/- 1 SD): 1.5 inch stroke, EMF 12 +/- 5%, RMS 16 +/- 5%; 2 inch stroke, EMF 30 +/- 6%, RMS 26 +/- 11%; 2.5 inch stroke, EMF 50 +/- 12%, RMS 40 +/- 20%. The phasic coronary flow signal during closed-chest compression indicated that all perfusion occurred during the relaxation phase of the massage cycle. We concluded that coronary blood flow is demonstrable during closed-chest massage, but that the magnitude is unlikely to be more than a fraction of normal

  4. MEASUREMENT OF BLOOD FLOW IN ARTERIA MENINGEA MEDIA OF PATIENTS WITH FREQUENT EPISODIC TENSION-TYPE HEADACHE NOT ASSOCIATED WITH PERICRANIAL TENDERNESS

    OpenAIRE

    A.A. Skoromets; L.G. Zaslavsky; E.P. Evdoshenko

    2008-01-01

    Twenty seven patients with frequent episodic tension-type headache not associated with pericrania! tenderness (TTH) aged from 18 to 69 years old were examined. Arteria meningea media (AMM) and brachiocephalic arteries (BCA) were examined by supersonic power Doppler scanning during the paroxysm of headache and without the paroxysm of headache. Results: Blood flow in AMM of patients with TTH was significantly different during the paroxysm of headache and without the paroxysm of headache (p<0...

  5. A microcomputer system for assessment of peripheral blood flow. An example of nasal blood flow.

    Science.gov (United States)

    Grönfors, T; Pyykkö, I; Aalto, H; Juhola, M; Ishizaki, H

    1991-01-01

    We have designed and implemented a microcomputer system for studying the effect of various mediator substances on the nasal blood flow. The system uses an IBM PC/AT microcomputer, which is connected with a Laser Doppler Flowmeter (LDF) and an iontophoretic drug application system. The LDF measures flux from the tissue that in the example is the inferior nasal turbinate. The flux is converted to digital form by an analog-digital converter of 12 bits. The program is implemented in the Pascal language. In the analysis, a flux level, amplitude, rise time and decay time of the pulse wave are determined. The effect of drugs on the flux can be studied by applying them iontophoretically. In the program the length and number of the drug application periods as well as the recording period are user-driven. In the nasal blood flow iontophoretically administered adrenaline reduced significantly the flux parameters and histamine canceled this effect. Tachyphylalaxis was a frequent observation in repeated measurements. The system can be used to evaluate the role of different transmitters in the etiology of chronic rhinitis.

  6. Measurements of regional cerebral blood flow (rCBF) using dynamic single-photon emission computed tomography (DSPECT): Definition of a generally acceptable normal range and follow-up checks after extracranial bypass surgery

    International Nuclear Information System (INIS)

    Kreisig, T.

    1986-01-01

    The usefulness of dynamic single-photon emission computed tomography was evaluated in 50 volunteers with unobtrusive cerebral findings, who were to provide the relevant standard values. It was found that the values measured were easily reproducible. Measurements in patients showing cerebrovascular disease that were carried out before and after extracranial bypass surgery did mostly not suggest any perceivable improvement of cerebral blood flow. In isolated cases the cerebral reserve was influenced favourably, as judged from measurements after administration of acetazolamide. (MBC) [de

  7. Measuring Your Peak Flow Rate

    Science.gov (United States)

    ... your child so they can help monitor your child's asthma symptoms . Why Should I Measure My Flow Rate? ... help parents determine what might be triggering their child's asthma. How Do You Use a Peak Flow Meter? ...

  8. The quantitative regional cerebral blood flow measurement with autoradiography method using 123I-IMP SPECT. Evaluation of arterialized venous blood sampling as a substitute for arterial blood sampling

    International Nuclear Information System (INIS)

    Ohnishi, Takashi; Yano, Takao; Nakano, Shinichi; Jinnouchi, Seishi; Nagamachi, Shigeki; Flores, L. II; Nakahara, Hiroshi; Watanabe, Katsushi.

    1996-01-01

    The purpose of this study is validation of calibrating a standard input function in autoradiography (ARG) method by one point venous blood sampling as a substitute for that by one point arterial blood sampling. Ten and 20 minutes after intravenous constant infusion of 123 I-IMP, arterialized venous blood sampling from a dorsal vein were performed on 15 patients having ischemic cerebrovascular disease. And arterial blood sampling from radial artery was performed 10 min after 123 I-IMP infusion. The mean difference rates of integrated input function between calibrated standard input function by arterial blood sampling at 10 min and that by venous blood sampling were 4.1±3% and 9.3±5.4% at 10 and 20 min after 123 I-IMP infusion, respectively. The ratio of venous blood radioactivity to arterial blood radioactivity at 10 min after 123 I-IMP infusion was 0.96±0.02. There was an excellent correlation between ARG method CBF values obtained by arterial blood sampling at 10 min and those obtained by arterialized venous blood sampling at 10 min. In conclusion, a substitution by arterialized venous blood sampling from dorsal hand vein for artery can be possible. The optimized time for arterialized venous blood sampling was 10 min after 123 I-IMP infusion. (author)

  9. Daily rhythm of cerebral blood flow velocity

    Directory of Open Access Journals (Sweden)

    Spielman Arthur J

    2005-03-01

    Full Text Available Abstract Background CBFV (cerebral blood flow velocity is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1 CBFV changes are due to sleep-associated processes or 2 time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day. Methods Eleven subjects underwent a modified constant routine protocol. CBFV from the middle cerebral artery was monitored by chronic recording of Transcranial Doppler (TCD ultrasonography. Other variables included core body temperature (CBT, end-tidal carbon dioxide (EtCO2, blood pressure, and heart rate. Salivary dim light melatonin onset (DLMO served as a measure of endogenous circadian phase position. Results A non-linear multiple regression, cosine fit analysis revealed that both the CBT and CBFV rhythm fit a 24 hour rhythm (R2 = 0.62 and R2 = 0.68, respectively. Circadian phase position of CBT occurred at 6:05 am while CBFV occurred at 12:02 pm, revealing a six hour, or 90 degree difference between these two rhythms (t = 4.9, df = 10, p Conclusion In conclusion, time of day variations in CBFV have an approximately 24 hour rhythm under constant conditions, suggesting regulation by a circadian oscillator. The 90 degree-phase angle difference between the CBT and CBFV rhythms may help explain previous findings of lower CBFV values in the morning. The phase difference occurs at a time period during which cognitive performance decrements have been observed and when both cardiovascular and cerebrovascular events occur more frequently. The mechanisms underlying this phase angle difference require further exploration.

  10. Assessing blood flow control through a bootstrap method

    OpenAIRE

    Simpson, D.M.; Panerai, R.B.; Ramos, E.G.; Lopes, J.M.A.; Villar Marinatto, M.N.; Nadal, J.; Evans, D.H.

    2004-01-01

    In order to assess blood flow control, the relationship between blood pressure and blood flow can be modeled by linear filters. We present a bootstrap method, which allows the statistical analysis of an index of blood flow control that is obtained from constrained system identification using an established set of pre-defined filters.

  11. Ocular Blood Flow and Normal Tension Glaucoma

    Directory of Open Access Journals (Sweden)

    Ning Fan

    2015-01-01

    Full Text Available Normal tension glaucoma (NTG is known as a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and glaucomatous visual field loss, even though the intraocular pressure (IOP does not exceed the normal range. The pathophysiology of NTG remains largely undetermined. It is hypothesized that the abnormal ocular blood flow is involved in the pathogenesis of this disease. A number of evidences suggested that the vascular factors played a significant role in the development of NTG. In recent years, the new imaging techniques, fluorescein angiography, color Doppler imaging (CDI, magnetic resonance imaging (MRI, and laser speckle flowgraphy (LSFG, have been used to evaluate the ocular blood flow and blood vessels, and the impaired vascular autoregulation was found in patients with NTG. Previous studies showed that NTG was associated with a variety of systemic diseases, including migraine, Alzheimer’s disease, primary vascular dysregulation, and Flammer syndrome. The vascular factors were involved in these diseases. The mechanisms underlying the abnormal ocular blood flow in NTG are still not clear, but the risk factors for glaucomatous optic neuropathy likely included oxidative stress, vasospasm, and endothelial dysfunction.

  12. The dose-response of canine focal gastric mucosal blood flow to misoprostol

    International Nuclear Information System (INIS)

    Gana, T.J.; Pherson, B.R.; Koo, J.

    1989-01-01

    The dose-response of focal gastric mucosal blood flow was measured simultaneously by laser-Doppler flowmetry and hydrogen gas clearance in the canine chambered gastric segment to topical misoprostol. Simultaneously obtained mucosal blood flow values showed a highly significant linear correlation in the basal but not misoprostol periods between the two techniques. Laser-Doppler flowmetry measured a dose-dependent increase in blood flow, while in contrast, hydrogen gas clearance showed a gradual decline in blood flow after misoprostol administration throughout all experiments. It is concluded that misoprostol dose-dependently and transiently increases focal gastric mucosal blood flow. However, only laser-Doppler flowmetry is sensitive enough to detect it. Although it can measure steady-state blood flow, owing to the duration of one measurement, hydrogen gas clearance is incapable of detecting rapid flow changes

  13. The dose-response of canine focal gastric mucosal blood flow to misoprostol

    Energy Technology Data Exchange (ETDEWEB)

    Gana, T.J.; Pherson, B.R.; Koo, J. (Alberta Univ., Edmonton, AB (Canada))

    1989-01-01

    The dose-response of focal gastric mucosal blood flow was measured simultaneously by laser-Doppler flowmetry and hydrogen gas clearance in the canine chambered gastric segment to topical misoprostol. Simultaneously obtained mucosal blood flow values showed a highly significant linear correlation in the basal but not misoprostol periods between the two techniques. Laser-Doppler flowmetry measured a dose-dependent increase in blood flow, while in contrast, hydrogen gas clearance showed a gradual decline in blood flow after misoprostol administration throughout all experiments. It is concluded that misoprostol dose-dependently and transiently increases focal gastric mucosal blood flow. However, only laser-Doppler flowmetry is sensitive enough to detect it. Although it can measure steady-state blood flow, owing to the duration of one measurement, hydrogen gas clearance is incapable of detecting rapid flow changes.

  14. Regional cerebral blood flow in neuropediatrics

    International Nuclear Information System (INIS)

    Junik, R.

    2001-01-01

    Single photon emission computed tomography can effectively and non-invasively measure regional blood flow. Mostly used 99mTc-HMPAO is a safe brain imaging agent for pediatric applications. The radiation dose is acceptable. Knowledge of the normal rCBF pattern, including normal asymmetries and variations due to age, is necessary prerequisite for the evaluation and reporting of the results of 99mTc-HMPAO brain SPECT studies in clinical practice. The interpretation of he rCBF study in a child requires knowledge of normal brain maturation. The aim of the present review is to focus on the contribution to clinical developmental neurology of SPECT The clinical use of SPECT in developmental neurology are epilepsy, brain death, acute neurological loss including stroke, language disorders, cerebral palsy, high-risk neonates, hypertension due to renovascular disease, traumatic brain injury, migraine, anorexia nervosa, autism, Gilles de la Tourette syndrome, attention deficit disorder-hyperactivity, and monitoring therapy. Sedation is not routinely used, rather each child is evaluated. However, drug sedation is mandatory in some uncooperative children. (author)

  15. Blood flow restricted exercise and vascular function.

    Science.gov (United States)

    Horiuchi, Masahiro; Okita, Koichi

    2012-01-01

    It is established that regular aerobic training improves vascular function, for example, endothelium-dependent vasodilatation and arterial stiffness or compliance and thereby constitutes a preventative measure against cardiovascular disease. In contrast, high-intensity resistance training impairs vascular function, while the influence of moderate-intensity resistance training on vascular function is still controversial. However, aerobic training is insufficient to inhibit loss in muscular strength with advancing age; thus, resistance training is recommended to prevent sarcopenia. Recently, several lines of study have provided compelling data showing that exercise and training with blood flow restriction (BFR) leads to muscle hypertrophy and strength increase. As such, BFR training might be a novel means of overcoming the contradiction between aerobic and high-intensity resistance training. Although it is not enough evidence to obtain consensus about impact of BFR training on vascular function, available evidences suggested that BFR training did not change coagulation factors and arterial compliance though with inconsistence results in endothelial function. This paper is a review of the literature on the impact of BFR exercise and training on vascular function, such as endothelial function, arterial compliance, or other potential factors in comparison with those of aerobic and resistance training.

  16. Blood Flow Restricted Exercise and Vascular Function

    Directory of Open Access Journals (Sweden)

    Masahiro Horiuchi

    2012-01-01

    Full Text Available It is established that regular aerobic training improves vascular function, for example, endothelium-dependent vasodilatation and arterial stiffness or compliance and thereby constitutes a preventative measure against cardiovascular disease. In contrast, high-intensity resistance training impairs vascular function, while the influence of moderate-intensity resistance training on vascular function is still controversial. However, aerobic training is insufficient to inhibit loss in muscular strength with advancing age; thus, resistance training is recommended to prevent sarcopenia. Recently, several lines of study have provided compelling data showing that exercise and training with blood flow restriction (BFR leads to muscle hypertrophy and strength increase. As such, BFR training might be a novel means of overcoming the contradiction between aerobic and high-intensity resistance training. Although it is not enough evidence to obtain consensus about impact of BFR training on vascular function, available evidences suggested that BFR training did not change coagulation factors and arterial compliance though with inconsistence results in endothelial function. This paper is a review of the literature on the impact of BFR exercise and training on vascular function, such as endothelial function, arterial compliance, or other potential factors in comparison with those of aerobic and resistance training.

  17. Cerebral blood flow changes in cluster headache

    International Nuclear Information System (INIS)

    Norris, J.W.; Hachinski, V.C.; Cooper, P.W.

    1976-01-01

    Serial cerebral blood flod studies performed by the intra-carotid 133 Xenon method were fortuitously determined during the course of a cluster headache in a 32 year old man. The initial study was performed about 10 min after the headache began and showed values at the upper limit of normal. Twenty min after the headache started a second procedure showed that the autoregulatory response on hyperventilation was normal. Ergotamine tartrate was given intra-muscularly 23 min after the headache began and there was partial relief. A third cerebral blood flow estimation showed abnormally high values. The probable reasons for this are discussed. (author)

  18. Regional cerebral blood flow levels as measured by xenon-CT in vascular territorial low-density areas after subarachnoid hemorrhage are not always ischemic

    International Nuclear Information System (INIS)

    Fainardi, E.; Tagliaferri, M.F.; Compagnone, C.; Tanfani, A.; Cocciolo, F.; Targa, L.; Chieregato, A.; Battaglia, R.; Frattarelli, M.; Pascarella, R.

    2006-01-01

    The aim of this study was to assess regional cerebral blood flow (rCBV) in areas of CT hypoattenuation appearing in the postoperative period in patients treated for aneurysmal subarachnoid hemorrhage (SAH) using xenon-enhanced CT scanning (Xe-CT). We analyzed 15 patients (5 male and 10 female; mean age 49.7±12.1 years) with SAH on CT performed on admission to hospital and who showed a low-density area within a well-defined vascular territory on CT scans after clipping or coiling of a saccular aneurysm. All zones of hypoattenuation were larger than 1 cm 2 and showed signs of a mass effect suggesting a subacute phase of evolution. Two aneurysms were detected in two patients. Aneurysms were located in the middle cerebral artery (n=7), in the anterior communicating artery (n=6), in the internal carotid artery (n=3), and in the posterior communicating artery (n=1). Treatments were surgical (n=8), endovascular (n=2) or both (n=1). A total of 36 Xe-CT studies were performed and rCBF values were measured in two different regions of interest (ROI): the low-density area, and an area of normal-appearing brain tissue located symmetrically in the contralateral hemisphere. rCBF levels were significantly lower in the low-density area than in the contralateral normal-appearing area (P 55 ml/100 g per minute) in 2/36 lesions (5.6%). Our study confirmed that rCBF is reduced in new low-density lesions related to specific vascular territories. However, only about one-third of the lesions showed rCBF levels consistent with irreversible ischemia and in a relatively high proportion of lesions, rCBF levels indicated penumbral, oligemic and hyperemic areas. (orig.)

  19. Study Of Topical Anti-Inflammatory Potency And Clinical Efficacy Of Formulations Of Mometasone And Betamethasone By Cutaneous Blood Flow Measurements In Psoriatic Patients Using Laser Doppler Velocimetry

    Directory of Open Access Journals (Sweden)

    Mulekar S. V

    1997-01-01

    Full Text Available Laser Doppier Velocimetry (LDV was used to measure cutaneous blood flow (CBF in psoriatic skin lesions to assess the effect of once daily application of Mometasone furoate (MF in a base claimed to possess a “reservoir” effect, as against Betamethasone-17-valarate (BV in a conventional cream base, applied twice daily, for 4 weeks. Bilaterally symmetrical active lesions were studied in 10 psoriatics, at baseline and at the end of 2 and 4 weeks’ treatment. The formulations were also evaluated for topical anti-inflammatory potency in terms of their ability to inhibit the Post-Ischaemic-Reactive-Hyperaemic-Response (PIRHR induced on normal uninvolved skin treated under occlusion. The lesions were also assessed subjectively for clinical Psoriatic Hyperaemia Index (PHI = CBF on lesions/CBF on uninvolved skin: 8.42 + 1.74 & 10.13 + 1.70 correlating with high CPI (9 + 0.50 & 9.1 + 0.51. During treatment with MF or BV, the lesions resolved rapidly, with a concomitant decrease in PHI and CPI (Week 2 : PHI = 3.40 + 0.46 & 5.19 + 1.65, CPI = 4.15 + 0.86& 5.20 + 0.87 and Week 4 : PHI = 1.99 + 0.23 & 2.81 + 0.74 CPI = 2.00 + 0.50 & 2.88 + 0.72 respectively. The two formulations Inhibited PIRHR to same extent (auc/min: Control = 1871 + 399.22, MF = 536.11 + 153.34 & BV = 567.5 + 110.76, indicating equal potency. The results show that pharmaceutical factor such as vehicle can significantly influence the clinical efficacy of corticoids.

  20. Change of cerebral blood flow distribution and vascular reserver according to age in Koreans measured by Tc-99m HMPAO brain SPECT

    International Nuclear Information System (INIS)

    Song, Ho Cheon; Bom, Hee Seung; Sohn, Hye Kyung; Jeong, Hwan Jeong; Min, Jung Jun; Kim, Ji Yeol; Lee Jae Tae; Moon, Dae Hyuk; Lee, Hee Kyung

    1999-01-01

    The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO. Thirty four right-handed normal volunteers (20 males, 14 females, mean age 40.3±24.9 years, range 4 to 82 years) were underwent rest/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in frontal, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Mean values of right to left ratios range from 1.004 to 1.018. rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalamic rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was 29.9±12.9%. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Quantitative assessment of CVR was possible by ACZ Tc-99m MHPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference

  1. Effects of dynamic exercise and its intensity on ocular blood flow in humans.

    Science.gov (United States)

    Hayashi, Naoyuki; Ikemura, Tsukasa; Someya, Nami

    2011-10-01

    Visual performance is impaired when the ocular blood flow decreases, indicating that ocular blood flow plays a role in maintaining visual performance during exercise. We examined the ocular blood flow response to incremental cycling exercise to test the hypothesis that ocular blood flow is relatively stable during dynamic exercise because of its autoregulatory nature. The blood flow in the inferior and superior temporal retinal arterioles (ITRA and STRA, respectively) and retinal and choroidal vessels (RCV), mean arterial pressure, and heart rate (HR) were measured at rest and during leg cycling in nine young and healthy subjects (26 ± 5 years, mean ± SD). Ocular blood flow was measured by laser speckle flowmetry. The exercise intensity was incremented by 30 W every 3 min until the subject was unable to maintain a position appropriate for measuring ocular blood flow. Blood flow data obtained during cycling exercise were categorized based on HR as follows: 120 bpm. Blood flow in the RCV increased with the exercise intensity: by 16 ± 8, 32 ± 13, and 40 ± 19% from baseline, respectively. However, blood flow and vascular conductance in the ITRA and STRA did not change significantly with exercise. These findings demonstrate for the first time that ocular blood flow increases in the retina and choroid, but not in the arterioles, with increasing exercise intensity during dynamic exercise.

  2. PET-measured heterogeneity in longitudinal myocardial blood flow in response to sympathetic and pharmacologic stress as a non-invasive probe of epicardial vasomotor dysfunction

    International Nuclear Information System (INIS)

    Schindler, Thomas H.; Facta, Alvaro D.; Prior, John O.; Campisi, Roxana; Inubushi, Masayuki; Kreissl, Michael C.; Zhang, Xiao-Li; Sayre, James; Dahlbom, Magnus; Schelbert, Heinrich R.

    2006-01-01

    We investigated whether a myocardial perfusion gradient during pharmacologically induced hyperemia also occurred during sympathetic stimulation with cold pressor testing (CPT), which commonly induces a paradoxical coronary vasoconstriction in individuals with coronary risk factors. Myocardial blood flow (MBF) was measured in absolute units (ml/g/min) with 13 N-ammonia and PET at rest, during CPT, and during pharmacologic vasodilation in 59 participants with coronary risk factors (''at risk'') and in 43 healthy individuals (controls). MBF was assessed globally as mean MBF, and in the mid and mid-distal myocardium of the left ventricle (LV). A decrease in MBF from mid to mid-distal LV myocardium was defined as MBF difference indicative of a perfusion gradient. The change in mean MBF to CPT (ΔMBF) in the at-risk group was significantly reduced compared with controls (0.05±0.19 vs 0.31±0.20 ml/g/min, p<0.0001), whereas mean MBF during pharmacologic vasodilation in the at-risk group tended to be lower than in controls (1.72±0.71 vs 2.00±0.64 ml/g/min, p=NS). Absolute MBFs during CPT and pharmacologic vasodilation were significantly lower in the mid-distal than in the mid LV myocardium, resulting in a significant MBF difference in the at-risk group (0.15±0.06 and 0.27±0.12 ml/g/min, p<0.0001) that was not observed in controls (0.007±0.05 and 0.014±0.10 ml/g/min, p=NS). In the at-risk group there was a significant correlation between the difference of mid to mid-distal MBF during CPT and that during pharmacologic vasodilation (r=0.43, p<0.004), suggesting functional alterations of epicardial vessels as the predominant cause for the observed MBF difference. The relative decrease in MBF from the mid to the mid-distal left-ventricular myocardium suggests an intracoronary pressure decline during CPT and pharmacologic vasodilation, which is likely to reflect an impairment of flow-mediated epicardial vasomotor function. (orig.)

  3. Glial and neuronal control of brain blood flow

    DEFF Research Database (Denmark)

    Attwell, David; Buchan, Alastair M; Charpak, Serge

    2010-01-01

    recognized that neurotransmitter-mediated signalling has a key role in regulating cerebral blood flow, that much of this control is mediated by astrocytes, that oxygen modulates blood flow regulation, and that blood flow may be controlled by capillaries as well as by arterioles. These conceptual shifts......Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... in our understanding of cerebral blood flow control have important implications for the development of new therapeutic approaches....

  4. Velocity estimation using synthetic aperture imaging [blood flow

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Jensen, Jørgen Arendt

    2001-01-01

    Presented an approach for synthetic aperture blood flow ultrasound imaging. Estimates with a low bias and standard deviation can be obtained with as few as eight emissions. The performance of the new estimator is verified using both simulations and measurements. The results demonstrate that a fully...

  5. Disparity in regional cerebral blood flow during electrically induced seizure

    DEFF Research Database (Denmark)

    Sestoft, D; Meden, P; Hemmingsen, R

    1993-01-01

    This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized on electroencepha...

  6. Patterns of regional cerebral blood flow in acute stroke

    DEFF Research Database (Denmark)

    Olsen, T S; Skriver, E B

    1981-01-01

    In a consecutive group of 56 stroke patients the regional cerebral blood flow was measured within 84 hours after stroke. A 254 multidetector scintillation camera and the intracarotid Xenon-133 injection method was used to study rCBF. Typical rCBF-patterns are described and compared to the findings...

  7. Simultaneous PET/MR imaging of the brain: feasibility of cerebral blood flow measurements with FAIR-TrueFISP arterial spin labeling MRI

    International Nuclear Information System (INIS)

    Stegger, Lars; Martirosian, Petros; Schick, Fritz; Schwenzer, Nina; Pfannenberg, Christina; Claussen, Claus D.; Bisdas, Sotirios; Kolb, Armin; Pichler, Bernd; Boss, Andreas

    2012-01-01

    Background Hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) with simultaneous data acquisition promises a comprehensive evaluation of cerebral pathophysiology on a molecular, anatomical, and functional level. Considering the necessary changes to the MR scanner design the feasibility of arterial spin labeling (ASL) is unclear. Purpose To evaluate whether cerebral blood flow imaging with ASL is feasible using a prototype PET/MRI device. Material and Methods ASL imaging of the brain with Flow-sensitive Alternating Inversion Recovery (FAIR) spin preparation and true fast imaging in steady precession (TrueFISP) data readout was performed in eight healthy volunteers sequentially on a prototype PET/MRI and a stand-alone MR scanner with 128 x 128 and 192 x 192 matrix sizes. Cerebral blood flow values for gray matter, signal-to-noise and contrast-to-noise ratios, and relative signal change were compared. Additionally, the feasibility of ASL as part of a clinical hybrid PET/MRI protocol was demonstrated in five patients with intracerebral tumors. Results Blood flow maps showed good delineation of gray and white matter with no discernible artifacts. The mean blood flow values of the eight volunteers on the PET/MR system were 51 ± 9 and 51 ± 7 mL/100 g/min for the 128 x 128 and 192 x 192 matrices (stand-alone MR, 57 ± 2 and 55 ± 5, not significant). The value for signal-to-noise (SNR) was significantly higher for the PET/MRI system using the 192 x 192 matrix size (P < 0.01), the relative signal change (dS) was significantly lower for the 192 x 192 matrix size (P = 0.02). ASL imaging as part of a clinical hybrid PET/MRI protocol could successfully be accomplished in all patients in diagnostic image quality. Conclusion ASL brain imaging is feasible with a prototype hybrid PET/MRI scanner, thus adding to the value of this novel imaging technique

  8. Cutaneous blood flow rate in areas with and without arteriovenous anastomoses during exercise

    DEFF Research Database (Denmark)

    Midttun, M.; Sejrsen, Per

    1998-01-01

    Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow......Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow...

  9. Quantitative myocardial blood flow with Rubidium-82 PET

    DEFF Research Database (Denmark)

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

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identificat......Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1...... pretest probability of CAD can support the clinical decision-making in treatment of CAD patients as a complementary tool to the invasive coronary angiography (CAG). Recently, several studies have proven Rubidium-82 ((82)Rb) PET's long-term prognostic value by a significant association between compromised...... global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability...

  10. Spectral analysis of blood flow in rat

    International Nuclear Information System (INIS)

    Arnautovic, M.; Jerkic, M.; Gal, V.

    1997-01-01

    Blood flow was continuously monitored in carotid, femoral and renal arteries in rats with acute renal failure and in the animals of control group. The spectral analysis of data were done using fast Fourier transform. Two characteristic peaks were obtained. The dominant component has frequency corresponding to heart rate, (4-7)Hz, while the frequency of the other peak is about 1 Hz. A physiological interpretation of the data is presented. (author)

  11. Regulation of bone blood flow in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Boushel, Robert; Hellsten, Ylva

    2018-01-01

    of cyclooxygenase (COX) enzyme, thus prostaglandin (PG) synthesis on femoral bone marrow blood flow by positron emission tomography in healthy young men at rest and during one leg dynamic exercise. In an additional group of healthy men, the role of adenosine (ADO) in the regulation of BBF during exercise......The mechanisms that regulate bone blood flow (BBF) in humans are largely unknown. Animal studies suggest that nitric oxide (NO) could be involved and in the present study we investigated the effects of inhibition of nitric oxide synthase (NOS) alone and in combination with inhibition.......036), but did not affect BBF significantly during exercise (5.5±1.4 ml/100g/min, p=0.25). On the other hand, while combined NOS and COX inhibition did not cause any further reduction of blood flow at rest (0.6±0.2 ml/100g/min), the combined blockade reduced BBF during exercise by ~21%, to 5.0±1.8 ml/100g/min (p...

  12. Cerebral blood flow in Binswanger's disease

    International Nuclear Information System (INIS)

    Kawabata, Keita; Tachibana, Hisao; Sugita, Minoru

    1991-01-01

    Eight patients with a clinical diagnosis of Binswanger's disease (BD) were evaluated with I-123 IMP SPECT. The SPECT findings were compared with those in 7 other patients with Alzheimer's disease (AD) and 9 normal subjects. The ratios of I-123 IMP in the temporal cortex, thalamus, and basal ganglia to that in the cerebellum were lower in the BD group than the normal group. The BD group had a higher ratio of the occipital cortex/the cerebellum than the control group, suggesting a decreased blood flow in the cerebellum. When I-123 IMP ratio in various areas to that in the occipital cortex was examined, both the BD and AD groups seemed to have a decreased blood flow over the whole cerebrum. The BD group had a lower I-123 IMP uptake in the thalamus and basal ganglia, and the AD group had it in the parietal cortex, relative to the occipital cortex. Blood flow patterns for BD were found to be different from those for AD. This suggests the difference in areas responsible for etiology between BD and AD. (N.K.)

  13. Red blood cell in simple shear flow

    Science.gov (United States)

    Chien, Wei; Hew, Yayu; Chen, Yeng-Long

    2013-03-01

    The dynamics of red blood cells (RBC) in blood flow is critical for oxygen transport, and it also influences inflammation (white blood cells), thrombosis (platelets), and circulatory tumor migration. The physical properties of a RBC can be captured by modeling RBC as lipid membrane linked to a cytoskeletal spectrin network that encapsulates cytoplasm rich in hemoglobin, with bi-concave equilibrium shape. Depending on the shear force, RBC elasticity, membrane viscosity, and cytoplasm viscosity, RBC can undergo tumbling, tank-treading, or oscillatory motion. We investigate the dynamic state diagram of RBC in shear and pressure-driven flow using a combined immersed boundary-lattice Boltzmann method with a multi-scale RBC model that accurately captures the experimentally established RBC force-deformation relation. It is found that the tumbling (TU) to tank-treading (TT) transition occurs as shear rate increases for cytoplasm/outer fluid viscosity ratio smaller than 0.67. The TU frequency is found to be half of the TT frequency, in agreement with experiment observations. Larger viscosity ratios lead to the disappearance of stable TT phase and unstable complex dynamics, including the oscillation of the symmetry axis of the bi-concave shape perpendicular to the flow direction. The dependence on RBC bending rigidity, shear modulus, the order of membrane spectrin network and fluid field in the unstable region will also be discussed.

  14. Dynamics of blood flow: twenty years of achievement

    International Nuclear Information System (INIS)

    Rosendorff, C.

    1988-01-01

    The physiology of blood circulation has evolved from the descriptive phenomenology of William Harvey's time to an interdisciplinary science, involving elements of fluid dynamics, vessel wall mechanics, electrophysiology, cell biology, biochemistry and molecular biology. Most of these new developments have occured during the lifetime of the South African Medical Research Council. Highlights of the research undertaken by the Council regarding circulatory physiology are given. In the 1960s the use of xenon-133 to study the flow of blood to the brain resulted in the first systematic description of cerebral blood flow and its control by sympathetic nerves. During the 1970s this technique was refined and the use of radioactive microspheres for the measurement of tissue blood flow was developed. Research concerning the control of blood vessels in the kidney was also carried out, and this showed that the sympathetic nerves control renal blood flow by releasing a local hormone called renin. The renal release of renin was later recognised as being important in the control of blood pressure. Another development was the discovery that vascular sensitivity to noradrenaline was increased in certain types of liver diseases. An analysis of the blood of patients with obstructive jaundice showed that the substance responsible for this noradrenaline effect was a combination of cholesterol and lipo-protein. This led to the theory that excessive cholesterol in the blood may be dangerous. In the late 1970s a shift in research emphasis to coronary artery physiology occurred and the 1980s saw research move into the area of cell biology

  15. Quantitative pixel-wise measurement of myocardial blood flow: the impact of surface coil-related field inhomogeneity and a comparison of methods for its correction.

    Science.gov (United States)

    Miller, Christopher A; Hsu, Li-Yueh; Ta, Allison; Conn, Hannah; Winkler, Susanne; Arai, Andrew E

    2015-02-11

    Surface coil-related field inhomogeneity potentially confounds pixel-wise quantitative analysis of perfusion CMR images. This study assessed the effect of surface coil-related field inhomogeneity on the spatial variation of pixel-wise myocardial blood flow (MBF), and assessed its impact on the ability of MBF quantification to differentiate ischaemic from remote coronary territories. Two surface coil intensity correction (SCIC) techniques were evaluated: 1) a proton density-based technique (PD-SCIC) and; 2) a saturation recovery steady-state free precession-based technique (SSFP-SCIC). 26 subjects (18 with significant CAD and 8 healthy volunteers) underwent stress perfusion CMR using a motion-corrected, saturation recovery SSFP dual-sequence protocol. A proton density (PD)-weighted image was acquired at the beginning of the sequence. Surface coil-related field inhomogeneity was approximated using a third-order surface fit to the PD image or a pre-contrast saturation prepared SSFP image. The estimated intensity bias field was subsequently applied to the image series. Pixel-wise MBF was measured from mid-ventricular stress images using the two SCIC approaches and compared to measurements made without SCIC. MBF heterogeneity in healthy volunteers was higher using SSFP-SCIC (24.8 ± 4.1%) compared to PD-SCIC (20.8 ± 3.0%; p = 0.009), however heterogeneity was significantly lower using either SCIC technique compared to analysis performed without SCIC (36.2 ± 6.3%). In CAD patients, the difference in MBF between remote and ischaemic territories was minimal when analysis was performed without SCIC (0.06 ± 0.91 mL/min/kg), and was substantially lower than with either PD-SCIC (0.50 ± 0.63 mL/min/kg; p = 0.013) or with SSFP-SCIC (0.63 ± 0.89 mL/min/kg; p = 0.005). In 6 patients, MBF quantified without SCIC was artifactually higher in the stenosed coronary territory compared to the remote territory. PD-SCIC and SSFP-SCIC had similar differences in MBF between remote and

  16. Manometer Measures Gas Flow

    Science.gov (United States)

    Rowlette, J. J.

    1983-01-01

    Simple apparatus measures time required for gas to displace known volume of water. Apparatus determines amount of gas generated in lead/acid cell during charging by measuring time required for gas to displace measured volume of water between markes in slanted manometer.

  17. The correlation between the rise of the tumor temperature during the hyperthermia treatment and the tumor blood flow measured by dynamic CT and 15O gas-positron emission tomography

    International Nuclear Information System (INIS)

    Hattori, Hideyuki

    1993-01-01

    This study was designed to determine the correlation between the rise of tumor temperature during hyperthermia treatment and the blood flow of the tumors measured by dynamic CT (DCT) and 15 O gas-positron emission tomography. In this report, we observed 20 patients with malignant tumors which underwent hyperthermia treatment. In each case, the temperature of the tumor was monitored with a photofiber sensor. DCT's and 15 O gas-positron emission tomographies were applied before the hyperthermia treatment. During the DCT, the tumor blood flow of each tumor was estimated by analyzing the time-dependent activity curve after a bolus injection. During the 15 O gas-positron emission tomography, the tumor blood flow was estimated by the C 15 O 2 -steady-state method. The value of the tumor blood flow estimated by DCT were proportional to those calculated by the 15 O gas-positron emission tomography. These values were inversely proportional to the rise of the temperature of the tumors during hyperthermia treatment. Our results imply that DCT as well as the 15 O gas-positron emission tomography can be used for the prediction of the tumor temperature rise during the hyperthermia treatment. (author)

  18. Recovery of testicular blood flow following ligation of testicular vessels

    International Nuclear Information System (INIS)

    Pascual, J.A.; Villanueva-Meyer, J.; Salido, E.; Ehrlich, R.M.; Mena, I.; Rajfer, J.

    1989-01-01

    To determine whether initial ligation of the testicular vessels of the high undescended testis followed by a delayed secondary orchiopexy is a viable alternative to the classical Fowler-Stephens procedure, a series of preliminary experiments were conducted in the rat in which testicular blood flow was measured by the 133-xenon washout technique before, and 1 hour and 30 days after ligation of the vessels. In addition, testicular histology, and testis and sex-accessory tissue weights were measured in 6 control, 6 sham operated and 6 testicular vessel ligated rats 54 days after vessel ligation. The data demonstrate that ligation and division of the testicular blood vessels produce an 80 per cent decrease in testicular blood flow 1 hour after ligation of the vessels. However, 30 days later testis blood flow returns to the control and pre-treatment value. There were no significant changes in testis or sex-accessory tissue weights 54 days after vessel ligation. Histologically, 4 of the surgically operated testes demonstrated necrosis of less than 25 per cent of the seminiferous tubules while 1 testis demonstrated more than 75 per cent necrosis. The rest of the tubules in all 6 testes demonstrated normal spermatogenesis. From this study we conclude that initial testicular vessel ligation produces an immediate decrease in testicular blood flow but with time the collateral vessels are able to compensate and return the testis blood flow to its normal pre-treatment value. These preliminary observations lend support for the concept that initial ligation of the testicular vessels followed by a delayed secondary orchiopexy in patients with a high undescended testis may be a possible alternative to the classical Fowler-Stephens approach

  19. Cerebral blood flow links insulin resistance and baroreflex sensitivity.

    Science.gov (United States)

    Ryan, John P; Sheu, Lei K; Verstynen, Timothy D; Onyewuenyi, Ikechukwu C; Gianaros, Peter J

    2013-01-01

    Insulin resistance confers risk for diabetes mellitus and associates with a reduced capacity of the arterial baroreflex to regulate blood pressure. Importantly, several brain regions that comprise the central autonomic network, which controls the baroreflex, are also sensitive to the neuromodulatory effects of insulin. However, it is unknown whether peripheral insulin resistance relates to activity within central autonomic network regions, which may in turn relate to reduced baroreflex regulation. Accordingly, we tested whether resting cerebral blood flow within central autonomic regions statistically mediated the relationship between insulin resistance and an indirect indicator of baroreflex regulation; namely, baroreflex sensitivity. Subjects were 92 community-dwelling adults free of confounding medical illnesses (48 men, 30-50 years old) who completed protocols to assess fasting insulin and glucose levels, resting baroreflex sensitivity, and resting cerebral blood flow. Baroreflex sensitivity was quantified by measuring the magnitude of spontaneous and sequential associations between beat-by-beat systolic blood pressure and heart rate changes. Individuals with greater insulin resistance, as measured by the homeostatic model assessment, exhibited reduced baroreflex sensitivity (b = -0.16, p baroreflex sensitivity was statistically mediated by cerebral blood flow in central autonomic regions, including the insula and cingulate cortex (mediation coefficients baroreflex sensitivity. Our observations may help to characterize the neural pathways by which insulin resistance, and possibly diabetes mellitus, relates to adverse cardiovascular outcomes.

  20. Effects of various factors on Doppler flow ultrasonic radial and coccygeal artery systolic blood pressure measurements in privately-owned, conscious dogs.

    Science.gov (United States)

    Mooney, Allison P; Mawby, Dianne I; Price, Joshua M; Whittemore, Jacqueline C

    2017-01-01

    The purpose of this study was to assess the effects of age, body condition score (BCS) and muscle condition score (MCS) on indirect radial and coccygeal Doppler systolic arterial blood pressure (SAP) measurements in dogs. Sixty-two privately-owned dogs were enrolled between June and July 2016. The BCS and MCS were determined by two investigators. Blood pressure was measured per published guidelines and using headphones, and the order of measurement site was randomized. Dogs were positioned in right lateral recumbency for radial measurements and sternal recumbency or standing for coccygeal measurements. Associations between SAP and other variables were assessed by correlation coefficients and analysis of covariance. Radial and coccygeal SAP measurements were moderately correlated ( r  = 0.45, P  < 0.01). Radial SAP measurements were higher than coccygeal SAP measurements (mean difference 9 mmHg, P  < 0.01), but discordance occurred in both directions. No difference was observed between the first measurement taken, the average of measurements 2-6, or the average of all 6 measurements for either the radial (128, 129, and 129 mmHg; P  = 0.36) or coccygeal (121, 122, and 122 mmHg; P  = 0.82) site. Associations were not found between SAP measurements for either site and age, weight, BCS, MCS, anxiety score, or cuff size. Heart rate decreased significantly from the start of acclimation to the end of the first data collection series regardless of site ( P  < 0.01). Initial measurement site can be based on patient and operator preference given lack of associations with patient variables, but the same site should be used for serial SAP measurements given discordant results between sites.

  1. Effects of various factors on Doppler flow ultrasonic radial and coccygeal artery systolic blood pressure measurements in privately-owned, conscious dogs

    Directory of Open Access Journals (Sweden)

    Allison P. Mooney

    2017-03-01

    Full Text Available Objective The purpose of this study was to assess the effects of age, body condition score (BCS and muscle condition score (MCS on indirect radial and coccygeal Doppler systolic arterial blood pressure (SAP measurements in dogs. Methods Sixty-two privately-owned dogs were enrolled between June and July 2016. The BCS and MCS were determined by two investigators. Blood pressure was measured per published guidelines and using headphones, and the order of measurement site was randomized. Dogs were positioned in right lateral recumbency for radial measurements and sternal recumbency or standing for coccygeal measurements. Associations between SAP and other variables were assessed by correlation coefficients and analysis of covariance. Results Radial and coccygeal SAP measurements were moderately correlated (r = 0.45, P < 0.01. Radial SAP measurements were higher than coccygeal SAP measurements (mean difference 9 mmHg, P < 0.01, but discordance occurred in both directions. No difference was observed between the first measurement taken, the average of measurements 2–6, or the average of all 6 measurements for either the radial (128, 129, and 129 mmHg; P = 0.36 or coccygeal (121, 122, and 122 mmHg; P = 0.82 site. Associations were not found between SAP measurements for either site and age, weight, BCS, MCS, anxiety score, or cuff size. Heart rate decreased significantly from the start of acclimation to the end of the first data collection series regardless of site (P < 0.01. Conclusions and Clinical Relevance Initial measurement site can be based on patient and operator preference given lack of associations with patient variables, but the same site should be used for serial SAP measurements given discordant results between sites.

  2. Effects of viscosity on cerebral blood flow after cardiac arrest

    NARCIS (Netherlands)

    Bisschops, L.L.A.; Pop, G.A.M.; Teerenstra, S.; Struijk, P.C.; Hoeven, J.G. van der; Hoedemaekers, C.W.E.

    2014-01-01

    OBJECTIVES: To determine blood viscosity in adult comatose patients treated with mild therapeutic hypothermia after cardiac arrest and to assess the relation between blood viscosity, cerebral blood flow, and cerebral oxygen extraction. DESIGN: Observational study. SETTING: Tertiary care university

  3. Improvements in Low-cost Ultrasonic Measurements of Blood Flow in "by-passes" Using Narrow & Broad Band Transit-time Procedures

    Science.gov (United States)

    Ramos, A.; Calas, H.; Diez, L.; Moreno, E.; Prohías, J.; Villar, A.; Carrillo, E.; Jiménez, A.; Pereira, W. C. A.; Von Krüger, M. A.

    The cardio-pathology by ischemia is an important cause of death, but the re-vascularization of coronary arteries (by-pass operation) is an useful solution to reduce associated morbidity improving quality of life in patients. During these surgeries, the flow in coronary vessels must be measured, using non-invasive ultrasonic methods, known as transit time flow measurements (TTFM), which are the most accurate option nowadays. TTFM is a common intra-operative tool, in conjunction with classic Doppler velocimetry, to check the quality of these surgery processes for implanting grafts in parallel with the coronary arteries. This work shows important improvements achieved in flow-metering, obtained in our research laboratories (CSIC, ICIMAF, COPPE) and tested under real surgical conditions in Cardiocentro-HHA, for both narrowband NB and broadband BB regimes, by applying results of a CYTED multinational project (Ultrasonic & computational systems for cardiovascular diagnostics). mathematical models and phantoms were created to evaluate accurately flow measurements, in laboratory conditions, before our new electronic designs and low-cost implementations, improving previous ttfm systems, which include analogic detection, acquisition & post-processing, and a portable PC. Both regimes (NB and BB), with complementary performances for different conditions, were considered. Finally, specific software was developed to offer facilities to surgeons in their interventions.

  4. Increase in calf post-occlusive blood flow and strength following short-term resistance exercise training with blood flow restriction in young women.

    Science.gov (United States)

    Patterson, Stephen D; Ferguson, Richard A

    2010-03-01

    The response of calf muscle strength, resting (R (bf)) and post-occlusive (PO(bf)) blood flow were investigated following 4 weeks resistance training with and without blood flow restriction in a matched leg design. Sixteen untrained females performed unilateral plantar-flexion low-load resistance training (LLRT) at either 25% (n = 8) or 50% (n = 8) one-repetition maximum (1 RM). One limb was trained with unrestricted blood flow whilst in the other limb blood flow was restricted with the use of a pressure applied cuff above the knee (110 mmHg). Regardless of the training load, peak PO(bf), measured using venous occlusion plethysmography increased when LLRT was performed with blood flow restriction compared to no change following LLRT with unrestricted blood flow. A significant increase (P training. Maximal dynamic strength (1 RM), maximal voluntary contraction and isokinetic strength at 0.52 and 1.05 rad s(-1) also increased (P training with blood flow restriction. Moreover, 1 RM increased to a greater extent following training at 50% 1 RM compared to 25% 1 RM. These results suggest that 4 weeks LLRT with blood flow restriction provides a greater stimulus to increase peak PO(bf) as well as strength parameters than LLRT with unrestricted blood flow.

  5. Cerebral blood flow in migraine and cortical spreading depression

    International Nuclear Information System (INIS)

    Lauritzen, M.

    1987-01-01

    In a series of migraine patients, carotid arteriography was carried out as part of the clinical evaluation. Nine patients developed a migrainous attack with focal neurological symptoms and headache after the angiography and during the subsequent, ongoing regional cerebral blood flow rCBF study. rCBF was measured by bolus injection of Xenon 133 into the internal carotid artery and a gamma camera with 254 collimated scintillation detectors covering the lateral aspect of the hemisphere. This technique depicts rCBF mainly at the level of the superficial cortex, with no depth resolution. The resolution is 1 cm 2 providing detailed spatial information of the cortical blood flow. Other methods for measuring local blood flow in animal and man employ a radioactive, freely diffusible tracer, in combination with an autoradiographic technique for the assessment of the tissue concentration, the so-called autoradiographic methods. In the series of patients with spontaneous migraine, rCBF was estimated using an in-vivo application of the autoradiographic principle. Xenon 133 was administered by inhalation and the time course of the arterial concentration curve was assessed by a scintillation detector over the upper right lung, since the arterial curve has been found to follow the shape of the lung curve. The rCBF was studied accompanying cortical spreading depression in rat experiments to evaluate whether this phenomenon could explain the blood flow changes in migraine. ( 14 C) iodoantipyrine was given as an intravenous bolus injection and the brain content of indicator was determined by tissue sample or autoradiography after 10 or 20 seconds of isotope circulation. The conditions of the autoradiographic methods are that the flow remains constant within the period of measuring, and that the region under study is homogenous with regard to flow and λ. (EG)

  6. Blood flow and oxygenation in peritendinous tissue and calf muscle during dynamic exercise in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Green, Sara Marie Ehrenreich

    2000-01-01

    1. Circulation around tendons may act as a shunt for muscle during exercise. The perfusion and oxygenation of Achilles' peritendinous tissue was measured in parallel with that of calf muscle during exercise to determine (1) whether blood flow is restricted in peritendinous tissue during exercise......, and (2) whether blood flow is coupled to oxidative metabolism. 2. Seven individuals performed dynamic plantar flexion from 1 to 9 W. Radial artery and popliteal venous blood were sampled for O2, peritendinous blood flow was determined by 133Xe-washout, calf blood flow by plethysmography, cardiac output...

  7. Regional cerebral blood flow in diabetic patients

    International Nuclear Information System (INIS)

    Nagamachi, Shigeki; Ono, Shinnichi; Nishikawa, Takushi

    1993-01-01

    N-isopropyl-p- 123 I-iodoamphetamine (IMP) was used to quantify the regional cerebral blood flow (r-CBF) in 11 diabetic patients (average age; 67.9 years) and 12 non-diabetic subjects (average age; 67.4 years), none of whom had (cerebrovascular disease (CVD) on CT studies. A reference sampling method by continuous arterial blood sampling was used to quantify r-CBF. There were no significant differences in physiological or laboratory data between diabetic and non-diabetic groups except for fasting plasma glucose and HbA 1c levels. The average of r-CBF in each region of cerebrum and cerebellum was significantly lower in diabetic group than that in the control group (p<0.01). These observations show that r-CBF of diabetic patients is reduced, even in the absence of findings of CVD on a CT study. (author)

  8. Skin blood flow changes during apneic spells in preterm infants

    NARCIS (Netherlands)

    Suichies, H.E.; Aarnoudse, J.G.; Okken, A.; Jentink, H.W.; de Mul, F.F.M.; Greve, Jan

    1989-01-01

    Changes in skin blood flow during apneic spells were determined in 18 preterm infants using a diode laser Doppler flow meter without light conducting fibres. Heart rate, nasal air flow, impedance pneumography, skin and incubator temperature and laser Doppler skin blood flow were recorded

  9. Tubuloglomerular feedback dynamics and renal blood flow autoregulation in rats

    DEFF Research Database (Denmark)

    Holstein-Rathlou, N H; Wagner, A J; Marsh, D J

    1991-01-01

    To decide whether tubuloglomerular feedback (TGF) can account for renal autoregulation, we tested predictions of a TGF simulation. Broad-band and single-frequency perturbations were applied to arterial pressure; arterial blood pressure, renal blood flow and proximal tubule pressure were measured....... Data were analyzed by linear systems analysis. Broad-band forcings of arterial pressure were also applied to the model to compare experimental results with simulations. With arterial pressure as the input and tubular pressure, renal blood flow, or renal vascular resistance as outputs, the model...... correctly predicted gain and phase only in the low-frequency range. Experimental results revealed a second component of vascular control active at 100-150 mHz that was not predicted by the simulation. Forcings at single frequencies showed that the system behaves linearly except in the band of 33-50 m...

  10. Cerebral blood flow response to functional activation

    DEFF Research Database (Denmark)

    Paulson, Olaf B; Hasselbalch, Steen G; Rostrup, Egill

    2010-01-01

    Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only...... most distant from the capillaries, whereas other studies point to a shift toward a higher degree of non-oxidative glucose consumption during activation. In this review, we argue that the key mechanism responsible for the regional CBF (rCBF) increase during functional activation is a tight coupling...... between rCBF and glucose metabolism. We assert that uncoupling of rCBF and oxidative metabolism is a consequence of a less pronounced increase in oxygen consumption. On the basis of earlier studies, we take into consideration the functional recruitment of capillaries and attempt to accommodate...

  11. Apparatus for measuring fluid flow

    Science.gov (United States)

    Smith, J.E.; Thomas, D.G.

    Flow measuring apparatus includes a support loop having strain gages mounted thereon and a drag means which is attached to one end of the support loop and which bends the sides of the support loop and induces strains in the strain gages when a flow stream impacts thereon.

  12. Effect of hematocrit and systolic blood pressure on cerebral blood flow in newborn infants

    International Nuclear Information System (INIS)

    Younkin, D.P.; Reivich, M.; Jaggi, J.L.; Obrist, W.D.; Delivoria-Papadopoulos, M.

    1987-01-01

    The effects of hematocrit and systolic blood pressure on cerebral blood flow were measured in 15 stable, low birth weight babies. CBF was measured with a modification of the xenon-133 ( 133 Xe) clearance technique, which uses an intravenous bolus of 133 Xe, an external chest detector to estimate arterial 133 Xe concentration, eight external cranial detectors to measure cephalic 133 Xe clearance curves, and a two-compartmental analysis of the cephalic 133 Xe clearance curves to estimate CBF. There was a significant inverse correlation between hematocrit and CBF, presumably due to alterations in arterial oxygen content and blood viscosity. Newborn CBF varied independently of systolic blood pressure between 60 and 84 mm Hg, suggesting an intact cerebrovascular autoregulatory mechanism. These results indicate that at least two of the factors that affect newborn animal CBF are operational in human newborns and may have important clinical implications

  13. Cutaneous Microvascular Blood Flow and Reactivity in Hypoxia

    Directory of Open Access Journals (Sweden)

    Benedikt Treml

    2018-03-01

    Full Text Available As is known, hypoxia leads to an increase in microcirculatory blood flow of the skin in healthy volunteers. In this pilot study, we investigated microcirculatory blood flow and reactive hyperemia of the skin in healthy subjects in normobaric hypoxia. Furthermore, we examined differences in microcirculation between hypoxic subjects with and without short-term acclimatization, whether or not skin microvasculature can acclimatize. Fourty-six healthy persons were randomly allocated to either short-term acclimatization using intermittent hypoxia for 1 h over 7 days at an FiO2 0.126 (treatment, n = 23 or sham short-term acclimatization for 1 h over 7 days at an FiO2 0.209 (control, n = 23. Measurements were taken in normoxia and at 360 and 720 min during hypoxia (FiO2 0.126. Microcirculatory cutaneous blood flow was assessed with a laser Doppler flowmeter on the forearm. Reactive hyperemia was induced by an ischemic stimulus. Measurements included furthermore hemodynamics, blood gas analyses and blood lactate. Microcirculatory blood flow increased progressively during hypoxia (12.3 ± 7.1–19.0 ± 8.1 perfusion units; p = 0.0002 in all subjects. The magnitude of the reactive hyperemia was diminished during hypoxia (58.2 ± 14.5–40.3 ± 27.4 perfusion units; p = 0.0003. Short-term acclimatization had no effect on microcirculatory blood flow. When testing for a hyperemic response of the skin's microcirculation we found a diminished signal in hypoxia, indicative for a compromised auto-regulative circulatory capacity. Furthermore, hypoxic short-term acclimatization did not affect cutaneous microcirculatory blood flow. Seemingly, circulation of the skin was unable to acclimatize using a week-long short-term acclimatization protocol. A potential limitation of our study may be the 7 days between acclimatization and the experimental test run. However, there is evidence that the hypoxic ventilatory response, an indicator of acclimatization, is increased for

  14. Role of hypotension in decreasing cerebral blood flow in porcine endotoxemia

    International Nuclear Information System (INIS)

    Miller, C.F.; Breslow, M.J.; Shapiro, R.M.; Traystman, R.J.

    1987-01-01

    The role of reduced arterial blood pressure (MAP) in decreasing cerebral blood flow (CBF) during endotoxemia was studied in pentobarbital-anesthetized pigs. Microspheres were used to measure regional CBF changes during MAP manipulations in animals with and without endotoxin. Endotoxin decreased MAP to 50 mmHg and decreased blood flow to the cortex and cerebellum without affecting cerebral cortical oxygen consumption (CMRo 2 ). Elevating MAP from 50 to 70 mmHg during endotoxemia with norepinephrine did not change cortical blood flow or CMRo 2 but increased cerebellar blood flow. Brain stem blood flow was not affected by endotoxin or norepinephrine. When MAP was decreased to 50 mmHg by hemorrhage without endotoxin, no change in blood flow to cortex, cerebellum, or brain stem was observed from base-line levels. These results suggest that decreased MAP below a lower limit for cerebral autoregulation does not account for the decreased CBF observed after endotoxin

  15. Blood flow and oxygenation in peritendinous tissue and calf muscle during dynamic exercise in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Green, Sara Marie Ehrenreich

    2000-01-01

    1. Circulation around tendons may act as a shunt for muscle during exercise. The perfusion and oxygenation of Achilles' peritendinous tissue was measured in parallel with that of calf muscle during exercise to determine (1) whether blood flow is restricted in peritendinous tissue during exercise...... with a rise in leg vascular conductance and microvascular haemoglobin volume, despite elevated systemic vascular resistance. 4. The parallel rise in calf muscle and peritendinous blood flow and fall in O2 saturation during exercise indicate that blood flow is coupled to oxidative metabolism in both tissue......, and (2) whether blood flow is coupled to oxidative metabolism. 2. Seven individuals performed dynamic plantar flexion from 1 to 9 W. Radial artery and popliteal venous blood were sampled for O2, peritendinous blood flow was determined by 133Xe-washout, calf blood flow by plethysmography, cardiac output...

  16. Blood transfusion in preterm infants improves intestinal tissue oxygenation without alteration in blood flow.

    Science.gov (United States)

    Banerjee, J; Leung, T S; Aladangady, N

    2016-11-01

    The objective of the study was to investigate the splanchnic blood flow velocity and oximetry response to blood transfusion in preterm infants according to postnatal age. Preterm infants receiving blood transfusion were recruited to three groups: 1-7 (group 1; n = 20), 8-28 (group 2; n = 21) and ≥29 days of life (group 3; n = 18). Superior mesenteric artery (SMA) peak systolic (PSV) and diastolic velocities were measured 30-60 min pre- and post-transfusion using Doppler ultrasound scan. Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) were measured from 15-20 min before to post-transfusion using near-infrared spectroscopy. The mean pretransfusion Hb in group 1, 2 and 3 was 11, 10 and 9 g/dl, respectively. The mean (SD) pretransfusion SMA PSV in group 1, 2 and 3 was 0·63 (0·32), 0·81 (0·33) and 0·97 (0·40) m/s, respectively, and this did not change significantly following transfusion. The mean (SD) pretransfusion sTOI in group 1, 2 and 3 was 36·7 (19·3), 44·6 (10·4) and 41·3 (10·4)%, respectively. The sTHI and sTOI increased (P transfusion in all groups. On multivariate analysis, changes in SMA PSV and sTOI following blood transfusion were not associated with PDA, feeding, pretransfusion Hb and mean blood pressure. Pretransfusion baseline splanchnic tissue oximetry and blood flow velocity varied with postnatal age. Blood transfusion improved intestinal tissue oxygenation without altering mesenteric blood flow velocity irrespective of postnatal ages. © 2016 International Society of Blood Transfusion.

  17. Capillary pericytes regulate cerebral blood flow in health and disease

    DEFF Research Database (Denmark)

    Hall, Catherine N; Reynell, Clare; Gesslein, Bodil

    2014-01-01

    Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate...... blood flow, capillaries dilate before arterioles and are estimated to produce 84% of the blood flow increase. In pathology, ischaemia evokes capillary constriction by pericytes. We show that this is followed by pericyte death in rigor, which may irreversibly constrict capillaries and damage the blood......-brain barrier. Thus, pericytes are major regulators of cerebral blood flow and initiators of functional imaging signals. Prevention of pericyte constriction and death may reduce the long-lasting blood flow decrease that damages neurons after stroke....

  18. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, Zoran [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Roessle, Martin; Schultheiss, Michael [University Medical Center Freiburg, Department of Gastroenterology, Freiburg (Germany); Euringer, Wulf; Langer, Mathias [University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Salem, Riad; Barker, Alex; Carr, James; Collins, Jeremy D. [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2015-09-15

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  19. Regional blood flow in experimental myositis ossificans

    International Nuclear Information System (INIS)

    Hierton, C.

    1983-01-01

    In a recent model for heterotopic bone formation, muscular oedema, swelling and necrosis is seen in the quadriceps muscle of rabbit hind limbs immobilized for at least 2 weeks when, from the second week, the immobilized limb is subjected to dayly forcible mobilization lasting about 5 min. According to this model, heterotopic calcification develops gradually from the second week of forcible mobilization and is located in the vastus intermedius region. Between the fourth and fifth week of immobilization and forcible mobilization, heterotopic bone formation is seen in virtually all cases. The histological findings are similar to those in human ectopic bone formation. In the present investigation the labelled microsphere technique was used to study the regional blood flow effects in the early development of myositis ossificans with this model. The results are quite different from those reported by other investigators on immobilization alone and point to a causal relation between regional blood flow and forcible mobilization of the immobilized rabbit hind limp. Prostaglandins as mediators between the traumatic inflammation, a part of the circulatory effects observed and the induction of a new bone is suggested. (author)

  20. POSIVA groundwater flow measuring techniques

    International Nuclear Information System (INIS)

    Oehberg, A.; Rouhiainen, P.

    2000-08-01

    Posiva Oy has carried out site characterisation for the final disposal of spent nuclear fuel in Finland since 1987. To meet the demanding needs to measure the hydraulic parameters in bedrock Posiva launched development of new flowmeter techniques including measuring methods and equipment in co-operation with PRG-Tec Oy. The techniques have been tested and used in the ongoing site investigations in Finland, in the underground Hard Rock Laboratory (HRL) at Aespoe in Sweden and in URL in Canada. The new methods are called difference flow and transverse flow methods. The difference flow method includes two modes, normal and detailed flow logging methods. In the normal mode the flow rate measurement is based on thermal pulse and thermal dilution methods, in the detailed logging mode only on thermal dilution method. The measuring ranges for flow rate with thermal pulse and dilution methods are 0.1-10 ml/min and 2-5000 ml/min, respectively. The difference flow method(normal mode) for small flows (0.1-10 ml/min) is based on measuring the pulse transit time and direction of a thermal pulse in the sensor. For high flows (2-5000 ml/min) the method is based on thermal dilution rate of a sensor. Direction is measured with monitoring thermistors. Inflow or outflow in the test interval is created due to natural or by pumping induced differences between heads in the borehole water and groundwater around the borehole. The single point resistance (and the temperature of borehole water) measurement is carried out simultaneously with the difference flow measurements, both in normal and detailed flow logging modes, while the tool is moving. The result is utilised for checking the exact depth of the tool. As the result a continuous log is obtained from which single fractures can be detected. The transverse flowmeter is able to measure the groundwater flow across a borehole. A special packer system guides the flow through the flow sensors. Four inflatable seals between conventional

  1. Femoral Blood Flow and Cardiac Output During Blood Flow Restricted Leg Press Exercise

    Science.gov (United States)

    Everett, M. E.; Hackney, K.; Ploutz-Snyder, L.

    2011-01-01

    Low load blood flow restricted resistance exercise (LBFR) causes muscle hypertrophy that may be stimulated by the local ischemic environment created by the cuff pressure. However, local blood flow (BF) during such exercise is not well understood. PURPOSE: To characterize femoral artery BF and cardiac output (CO) during leg press exercise (LP) performed at a high load (HL) and low load (LL) with different levels of cuff pressure. METHODS: Eleven subjects (men/women 4/7, age 31.4+/-12.8 y, weight 68.9+/-13.2 kg, mean+/-SD) performed 3 sets of supine left LP to fatigue with 90 s of rest in 4 conditions: HL (%1-RM/cuff pressure: 80%/0); LL (20%/0); LBFR(sub DBP) (20%/1.3 x diastolic blood pressure, BP); LBFR(sub SBP) (20%/1.3 x supine systolic BP). The cuff remained inflated throughout the LBFR exercise sessions. Artery diameter, velocity time integral (VTI), and stroke volume (SV) were measured using Doppler ultrasound at rest and immediately after each set of exercise. Heart rate (HR) was monitored using a 3-lead ECG. BF was calculated as VTI x vessel cross-sectional area. CO was calculated as HR x SV. The data obtained after each set of exercise were averaged and used for analyses. Multi-level modeling was used to determine the effect of exercise condition on dependent variables. Statistical significance was set a priori at p LL (9.92+/-0.82 cm3) > LBFR(sub dBP)(6.47+/-0.79 cm3) > LBFR(sub SBP) (3.51+/-0.59 cm3). Blunted exercise induced increases occurred in HR, SV, and CO after LBFR compared to HL and LL. HR increased 45% after HL and LL and 28% after LBFR (p<0.05), but SV increased (p<0.05) only after HL. Consequently, the increase (p<0.05) in CO was greater in HL and LL (approximately 3 L/min) than in LBFR (approximately 1 L/min). CONCLUSION: BF during LBFR(sub SBP) was 1/3 of that observed in LL, which supports the hypothesis that local ischemia stimulates the LBFR hypertrophic response. As the cuff did not compress the artery, the ischemia may have occurred

  2. Sympathetic reflex control of blood flow in human peripheral tissues

    DEFF Research Database (Denmark)

    Henriksen, O

    1991-01-01

    sympathetic vasoconstrictor reflexes are blocked. Blood flow has been measure by the local 133Xe-technique. The results indicate the presence of spinal as well as supraspinal sympathetic vasoconstrictor reflexes to human peripheral tissues. Especially is emphasized the presence of a local sympathetic veno......Sympathetic vasoconstrictor reflexes are essential for the maintenance of arterial blood pressure in upright position. It has been generally believed that supraspinal sympathetic vasoconstrictor reflexes elicited by changes in baroreceptor activity play an important role. Recent studies on human...

  3. Holographic laser Doppler imaging of pulsatile blood flow

    Science.gov (United States)

    Bencteux, Jeffrey; Pagnoux, Pierre; Kostas, Thomas; Bayat, Sam; Atlan, Michael

    2015-06-01

    We report on wide-field imaging of pulsatile motion induced by blood flow using heterodyne holographic interferometry on the thumb of a healthy volunteer, in real time. Optical Doppler images were measured with green laser light by a frequency-shifted Mach-Zehnder interferometer in off-axis configuration. The recorded optical signal was linked to local instantaneous out-of-plane motion of the skin at velocities of a few hundreds of microns per second and compared to blood pulse monitored by plethysmoraphy during an occlusion-reperfusion experiment.

  4. [Assessment of maternal cerebral blood flow in patients with preeclampsia].

    Science.gov (United States)

    Mandić, Vesna; Miković, Zeljko; Dukić, Milan; Vasiljević, Mladenko; Filimonović, Dejan; Bogavac, Mirjana

    2005-01-01

    Systemic vasoconstriction in preeclamptic patients increases vascular resistance, and is manifested by increased arterial blood flow velocity. The aim of the study is to evaluate if there is a change of Doppler indices in maternal medial cerbral artery (MCA) in severe preeclampsia due to: 1) severity of clinical symptoms, 2) the begining of eclamptic attack and 3) the application of anticonvulsive therapy. A prospective clinical study included 92 pregnant women, gestational age 28-36 weeks. They were divided into three groups: normotensive (n=30), mild preeclampsia (n=33), and severe preeclampsia (n=29). We investigated maternal cerebral circulation by assessing the MCA. We registrated: pulsatility index (Pi), resistance index (Ri), systolic/diastolic ratio (S/D), and the maximum systolic, end diastolic and medium velocity. Patients with severe preeclampsia were divided into two subgroups. subgroup 1 included patients without symptoms of threatening eclampsia (n=18; 62.06%); while subgroup 2 included those with symptoms of preeclampsia (n=11; 37.94%). All patients with severe preeclampsia were treated with magnesium sulfate (MgSO4), and cerebral blood flow was measured before and after the treatment. Statistical analysis was done by oneway ANOVA, Student t-test and t-paired sample test. The difference was considered to be significant if ppreeclamsia we registrated significantly increased values of all velocities (patients with signs of threatening eclampsia). After MgSO4 treatment in patients with severe preeclampsia significantly decreased values of Pi, Ri, S/D ratio and all velocities were registered. In the studied group of patients with severe preclampsia we found increased velocity values, Pi and Ri, especially in patients with signs of threatened eclampsia, suggesting that blood vessels changes are most prominent in severe preeclampsia. Cerebral blood flow meassurements can be used as a clinical test for the prediction of eclampsia. Magnesium-sulfate (MgSO4

  5. Resistin increases islet blood flow and decreases subcutaneous adipose tissue blood flow in anaesthetized rats.

    Science.gov (United States)

    Danielsson, T; Fredriksson, L; Jansson, L; Henriksnäs, J

    2009-02-01

    Resistin is an adipokine which has been suggested to participate in the induction of insulin resistance associated with type 2 diabetes. The aim of the present study was to investigate whether acute administration of resistin influences tissue blood perfusion in rats. Resistin was administered as an intravenous infusion of 7.5 microg h(-1) (1.5 mL h(-1)) for 30 min to rats anaesthetized with thiobutabarbital. A microsphere technique was used to estimate the blood flow to six different depots of white adipose tissue (WAT), brown adipose tissue (BAT), as well as to the pancreas, islets, duodenum, colon, kidneys, adrenal glands and liver. Resistin administration led to an increased blood flow to the pancreas and islets and a decrease in subcutaneous WAT and BAT. Intra-abdominal white adipose tissue blood flow and that to other organs were not affected. Acute administration of resistin markedly affects the blood perfusion of both the pancreas and subcutaneous white adipose tissue depots. At present it is unknown whether resistin exerts a direct effect on the vasculature, or works through local or systemic activation of endothelial cells and/or macrophages. The extent to which this might contribute to the insulin resistance caused by resistin is yet unknown.

  6. The Effect of Pulsatile Versus Nonpulsatile Blood Flow on Viscoelasticity and Red Blood Cell Aggregation in Extracorporeal Circulation.

    Science.gov (United States)

    Ahn, Chi Bum; Kang, Yang Jun; Kim, Myoung Gon; Yang, Sung; Lim, Choon Hak; Son, Ho Sung; Kim, Ji Sung; Lee, So Young; Son, Kuk Hui; Sun, Kyung

    2016-06-01

    Extracorporeal circulation (ECC) can induce alterations in blood viscoelasticity and cause red blood cell (RBC) aggregation. In this study, the authors evaluated the effects of pump flow pulsatility on blood viscoelasticity and RBC aggregation. Mongrel dogs were randomly assigned to two groups: a nonpulsatile pump group (n=6) or a pulsatile pump group (n=6). After ECC was started at a pump flow rate of 80 mL/kg/min, cardiac fibrillation was induced. Blood sampling was performed before and at 1, 2, and 3 hours after ECC commencement. To eliminate bias induced by hematocrit and plasma, all blood samples were adjusted to a hematocrit of 45% using baseline plasma. Blood viscoelasticity, plasma viscosity, hematocrit, arterial blood gas analysis, central venous O2 saturation, and lactate were measured. The blood viscosity and aggregation index decreased abruptly 1 hour after ECC and then remained low during ECC in both groups, but blood elasticity did not change during ECC. Blood viscosity, blood elasticity, plasma viscosity, and the aggregation index were not significantly different in the groups at any time. Hematocrit decreased abruptly 1 hour after ECC in both groups due to dilution by the priming solution used. After ECC, blood viscoelasticity and RBC aggregation were not different in the pulsatile and nonpulsatile groups in the adult dog model. Furthermore, pulsatile flow did not have a more harmful effect on blood viscoelasticity or RBC aggregation than nonpulsatile flow.

  7. Renal blood flow and metabolism after cold ischaemia

    DEFF Research Database (Denmark)

    Henriksen, J H; Petersen, H K

    1984-01-01

    Peroperative measurements of renal blood flow (RBF), renal O2-uptake, and renal venous lactate/pyruvate (L/P) ratio were performed before and after a period of 30-71 min of hypothermic (10-15 degrees C) renal ischaemia in nine patients, undergoing surgery for renal calculi. Before ischaemia, RBF.......01) immediately after re-established perfusion and 36% (P less than 0.02) 30 min later. In one additional patient, who had a short warm ischaemia (8 min), the flow pattern was the same. As arterial pressure remained constant, the reduced RBF signifies an increased renal vascular resistance. Renal O2-uptake...

  8. Pancreatic islet blood flow during euglycaemic, hyperinsulinaemic clamp in anaesthetized rats.

    Science.gov (United States)

    Jansson, L; Andersson, A; Bodin, B; Källskog, O

    2007-04-01

    Previous studies have demonstrated that pancreatic islet blood flow is crucially dependent on blood glucose concentration. Thus, hyperglycaemia increases and hypoglycaemia decreases islet blood perfusion, by a combination of nervous and metabolic signals. The aim of the present study was to evaluate if hyperinsulinaemia, without associated hypoglycaemia, affects islet blood flow. Thiobutabarbital-anaesthetized Wistar-Furth rats were subjected to an euglycaemic, hyperinsulinaemic clamp, that is they were infused for 60 min with either saline, insulin (18 mU kg(-1) min(-1)), glucose (27 mg kg(-1) min(-1)) or both glucose and insulin. This was followed by islet blood flow measurements with a microsphere technique. Animals receiving only glucose doubled their blood glucose and serum insulin concentrations, whereas rats receiving only insulin had blood glucose concentrations <2 mmol L(-1) and a 10-fold increase in serum insulin concentrations. Animals given simultaneous glucose and insulin had normal blood glucose concentrations but a 10-fold increase in serum insulin concentrations. Total pancreatic blood flow was unaffected in all animals. Islet blood flow was increased in hyperglycaemic and decreased in hypoglycaemic rats compared with control rats. Islet blood flow did not differ between clamped and control rats. Serum insulin concentration per se does not affect islet blood flow, whereas the ambient blood glucose concentration is of major importance in this context.

  9. Cerebral blood flow changes during sodium-lactate-induced panic attacks

    International Nuclear Information System (INIS)

    Stewart, R.S.; Devous, M.D. Sr.; Rush, A.J.; Lane, L.; Bonte, F.J.

    1988-01-01

    Dynamic single-photon emission computed axial tomography (CAT) with inhaled xenon-133 was used to measure regional cerebral blood flow in 10 drug-free patients with DSM-III-diagnosed panic disorder and in five normal control subjects. All subjects underwent regional cerebral blood flow studies while at rest or during normal saline infusion and during sodium lactate infusion. Six of the 10 patients and none of the control subjects experienced lactate-induced panic attacks. Lactate infusion markedly raised hemispheric blood flow levels in both control subjects and patients who did not panic. Patients who did panic experienced either a minimal increase or a decrease in hemispheric blood flow

  10. Cerebral blood flow and metabolism during sleep

    DEFF Research Database (Denmark)

    Madsen, Peter Lund; Vorstrup, S

    1991-01-01

    A review of the current literature regarding sleep-induced changes in cerebral blood flow (CBF) and cerebral metabolic rate (CMR) is presented. Early investigations have led to the notion that dreamless sleep was characterized by global values of CBF and CMR practically at the level of wakefulness......, while rapid eye movement (REM) sleep (dream sleep) was a state characterized by a dramatically increased level of CBF and possibly also of CMR. However, recent investigations firmly contradict this notion. Investigations on CBF and CMR performed during non-REM sleep, taking the effect of different...... levels of sleep into consideration, show that light sleep (stage II) is characterized by global levels of CBF and CMR only slightly reduced by 3-10% below the level associated with wakefulness, whereas CBF and CMR during deep sleep (stage III-IV) is dramatically reduced by 25-44%. Furthermore, recent...

  11. [Prognostic Doppler ultrasound examination of fetal arteries blood flow].

    Science.gov (United States)

    Sieroszewski, Piotr; Sabatowska, Małgorzata; Karowicz-Bilińska, Agata; Suzin, Jacek

    2002-08-01

    Early detection of fetal risk is one of the main issues in today obstetrics. Ultrasound diagnostics plays a significant role, as the introduction of Doppler imaging method in the evaluation of blood flow has enabled non-invasive assessment of uteroplacental circulation. Therefore, we have analysed foetal three arteries: umbilical artery, middle cerebral artery and renal artery after determining the normal range for the analysed parameters. 1. Comparison of the obtained blood flow indices (S/D, RI, PI) in the umbilical artery, middle cerebral artery and renal artery of foetuses from normal and complicated full-term pregnancies. 2. Determination of indices: umbilical-cerebral and renal-cerebral in normal and pathological pregnancy. 3. Evaluation of feasibility of the analysed flow parameters for the detection of intrauterine foetal hypoxia. We have examined 151 women, who were divided into control group--101 pregnant women with normal pregnancy and study group--50 pregnant women with complicated pregnancy. All pregnant women underwent ultrasound examination using the Hitachi EUB 515 C (Japan) scanner with 3.5 MHz convex probe, connected to the colour pulsed Doppler. The study consisted of the biometric measurements and evaluation of the spectrum of blood flow in the umbilical artery, middle cerebral artery and renal artery. We have determined following indices: a) systolic-diastolic ratio S/D, resistance index RI, pulsatility index PI, b) umbilical-cerebral ratio P/M. (PI ua/PI mca), renal--cerebral ratio N/M (PI ra/PI mca). Statistically significant difference was found between the study and control groups for all the flow indices assessed (S/D, RI, PI) for the middle cerebral artery, for the indices P/M and N/M. (p < 0.001) and pulsatility index in the renal artery (p < 0.01). Similar, although slightly smaller difference (p < 0.05) was seen for the values of flow parameters in the umbilical artery. 1) Evaluation of blood flow in the middle cerebral artery, and in

  12. A theoretical computerized study for the electrical conductivity of arterial pulsatile blood flow by an elastic tube model.

    Science.gov (United States)

    Shen, Hua; Zhu, Yong; Qin, Kai-Rong

    2016-12-01

    The electrical conductivity of pulsatile blood flow in arteries is an important factor for the application of the electrical impedance measurement system in clinical settings. The electrical conductivity of pulsatile blood flow depends not only on blood-flow-induced red blood cell (RBC) orientation and deformation but also on artery wall motion. Numerous studies have investigated the conductivity of pulsatile blood based on a rigid tube model, in which the effects of wall motion on blood conductivity are not considered. In this study, integrating Ling and Atabek's local flow theory and Maxwell-Fricke theory, we develop an elastic tube model to explore the effects of wall motion as well as blood flow velocity on blood conductivity. The simulation results suggest that wall motion, rather than blood flow velocity, is the primary factor that affects the conductivity of flowing blood in arteries. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  13. Cerebral autoregulation control of blood flow in the brain

    CERN Document Server

    Payne, Stephen

    2016-01-01

    This Brief provides a comprehensive introduction to the control of blood flow in the brain. Beginning with the basic physiology of autoregulation, the author goes on to discuss measurement techniques, mathematical models, methods of analysis, and relevant clinical conditions, all within this single volume. The author draws together this disparate field, and lays the groundwork for future research directions. The text gives an up-to-date review of the state of the art in cerebral autoregulation, which is particularly relevant as cerebral autoregulation moves from the laboratory to the bedside. Cerebral Autoregulation will be useful to researchers in the physical sciences such as mathematical biology, medical physics, and biomedical engineering whose work is concerned with the brain. Researchers in the medical sciences and clinicians dealing with the brain and blood flow, as well as industry professionals developing techniques such as ultrasound, MRI, and CT will also find this Brief of interest.

  14. Subcutaneous blood flow in early male pattern baldness

    International Nuclear Information System (INIS)

    Klemp, P.; Peters, K.; Hansted, B.

    1989-01-01

    The subcutaneous blood flow (SBF) was measured by the 133 Xe washout method in the scalp of 14 patients with early male pattern baldness. Control experiments were performed in 14 normal haired men matched for age. The SBF in the scalp of the normal individuals was about 10 times higher than previously reported SBF values in other anatomical regions. In patients with early male pattern baldness, SBF was 2.6 times lower than the values found in the normal individuals (13.7 +/- 9.6 vs 35.7 +/- 10.5 ml/100 g/min-1). This difference was statistically significant (p much less than 0.001). A reduced nutritive blood flow to the hair follicles might be a significant event in the pathogenesis of early male pattern baldness

  15. Cerebral blood flow simulations in realistic geometries

    Directory of Open Access Journals (Sweden)

    Szopos Marcela

    2012-04-01

    Full Text Available The aim of this work is to perform the computation of the blood flow in all the cerebral network, obtained from medical images as angiographies. We use free finite elements codes as FreeFEM++. We first test the code on analytical solutions in simplified geometries. Then, we study the influence of boundary conditions on the flow and we finally perform first computations on realistic meshes. L’objectif est ici de simuler l’écoulement sanguin dans tout le réseau cérébral (artériel et veineux obtenu à partir d’angiographies cérébrales 3D à l’aide de logiciels d’éléments finis libres, comme FreeFEM++. Nous menons d’abord une étude détaillée des résultats sur des solutions analytiques et l’influence des conditions limites à imposer dans des géométries simplifiées avant de travailler sur les maillages réalistes.

  16. pO2 and regional blood flow in a rabbit model of limb ischemia.

    Science.gov (United States)

    Grinberg, Oleg Y; Hou, Huagang; Grinberg, Stalina A; Moodie, Karen L; Demidenko, Eugene; Friedman, Bruce J; Post, Mark J; Swartz, Harold M

    2004-06-01

    Oxygen tension (pO2) in muscles and regional blood flow were measured in a rabbit model of limb ischemia. pO2 was measured repetitively by EPR oximetry with EMS char in four different muscle groups in the same animals. Blood flow in the same muscles at several time points was measured using microspheres. A linear mixed effects model was developed to analyze the data on pO2 and blood flow. The results suggest that while under normal conditions pO2 in muscles does not depend significantly on blood flow, immediately after arterial occlusion pO2 correlates linearly with blood flow. Within two weeks of occlusion the pO2 is recovered to 45% of baseline. This study demonstrates, for the first time, the applicability of EPR oximetry in animals larger than rodents.

  17. Retinal blood flow is increased in type 1 diabetes mellitus patients with advanced stages of retinopathy

    NARCIS (Netherlands)

    Nguyen, Hoang-Ton; van Duinkerken, Eelco; Verbraak, Frank D.; Polak, Bettine C. P.; Ringens, Peter J.; Diamant, Michaela; Moll, Annette C.

    2016-01-01

    Diabetic retinopathy (DRP) is a common microvascular complication seen in patients with type 1 diabetes mellitus (T1DM). The effects of T1DM and concomitant (proliferative) DRP on retinal blood flow are currently unclear. Therefore, we measured retinal vascular blood flow in T1DM patients with and

  18. Local regulation of blood flow evaluated simultaneously by 133-xenon washout and laser Doppler flowmetry

    International Nuclear Information System (INIS)

    Engelhart, M.; Petersen, L.J.; Kristensen, J.K.

    1988-01-01

    The laser Doppler flowmeter and the 133-Xenon washout techniques of measuring cutaneous blood flow were compared for measuring the vasoconstrictor response of the hand during orthostatic maneuvres. Important discrepancies were detected for the two methods. When the hand was lowered by 40 cm a 40% decrease in blood flow was detected by the 133-Xenon method, while a 60% decrease was seen by the laser Doppler technique. Lowering the hand by 50 cm resulted in no further blood flow decrease when using the 133-Xenon method, but an 80% blood flow decrease was recorded with the laser Doppler method. A marked decrease in blood flow was recorded by the laser Doppler technique in hands that were sympathectomized or a hand that was subjected to a nerve blockade, strategies which should eliminate the orthostatic vasoconstrictor response of superficial cutaneous vessels. The 133-Xenon technique did not detect any blood flow changes in hands without sympathetic tone. We found the laser Doppler flowmetry technique unsatisfactory for measurement of blood flow changes that occur in nutritional vessels as this method measures total skin blood flow including non-capillary vessels

  19. Should blood flow during cardiopulmonary bypass be individualized more than to body surface area?

    DEFF Research Database (Denmark)

    Thomassen, Sisse Anette; Larsson, A; Andreasen, Jan Jesper

    Blood flow during cardiopulmonary bypass (CPB) is calculated on body surface area (BSA). Increasing comorbidity, age and weight of today's cardiac patients question this calculation as it may not reflect individual metabolic requirement. The hypothesis was that a measured cardiac index (CI) prior...... not improve cerebral and systemic oxygenation compared to a blood flow based on BSA....

  20. Mucosal/submucosal blood flow in the gut wall determined by local washout of 133Xenon

    DEFF Research Database (Denmark)

    Mortensen, Peter; Olsen, J; Bülow, J

    1991-01-01

    A 133Xe washout technique for measuring the blood flow in the intestinal mucosa is introduced and evaluated. In 11 anaesthetized pigs a laparotomy was performed and the mucosal blood flow rate in the intestine of the pig was determined by a local epimucosal application of 133Xe. In both the colon...

  1. Laser speckle contrast imaging for monitoring changes in microvascular blood flow

    DEFF Research Database (Denmark)

    Ambrus, Rikard; Strandby, Rune B.; Svendsen, Lars Bo

    2016-01-01

    BACKGROUND/AIMS: Microvascular blood flow is essential for healing and predicts surgical outcome. The aim of the current study was to investigate the relation between fluxes measured with the laser speckle contrast imaging (LSCI) technique and changes in absolute blood flow. In addition, we studied...

  2. Diet-induced changes in subcutaneous adipose tissue blood flow in man

    DEFF Research Database (Denmark)

    Simonsen, L; Bülow, J; Astrup, A

    1990-01-01

    The effect of a carbohydrate-rich meal on subcutaneous adipose tissue blood flow was studied with and without continuous i.v. infusion of propranolol in healthy volunteers. The subcutaneous adipose tissue blood flow was measured with the 133Xe washout method in three different locations: the fore...

  3. Microvascular Branching as a Determinant of Blood Flow by Intravital Particle Imaging Velocimetry

    Science.gov (United States)

    Parsons-Wingerter, Patricia; McKay, Terri L.; Vickerman, Mary B.; Wernet, Mark P.; Myers, Jerry G.; Radhakrishnan, Krishnan

    2007-01-01

    The effects of microvascular branching on blood flow were investigated in vivo by microscopic particle imaging velocimetry (micro-PIV). We use micro-PIV to measure blood flow by tracking red blood cells (RBC) as the moving particles. Velocity flow fields, including flow pulsatility, were analyzed for the first four branching orders of capillaries, postcapillary venules and small veins of the microvascular network within the developing avian yolksac at embryonic day 5 (E5). Increasing volumetric flowrates were obtained from parabolic laminar flow profiles as a function of increasing vessel diameter and branching order. Maximum flow velocities increased approximately twenty-fold as the function of increasing vessel diameter and branching order compared to flow velocities of 100 - 150 micron/sec in the capillaries. Results from our study will be useful for the increased understanding of blood flow within anastomotic, heterogeneous microvascular networks.

  4. Assessment of hand blood flow: a modified technique

    International Nuclear Information System (INIS)

    Kirsh, J.C.; Tepperman, P.S.

    1985-01-01

    A blood flow artifact has been identified with the conventional bolus-injection technique in radionuclide studies of hand disorders. The artifact, consisting of increased blood flow on the injected side, was demonstrated in 22 of 25 subjects. Using a modified injection technique to allow time for local blood flow to return to the basal state, the artifact could be eliminated in 19 of 23 additional subjects. Use of this simple protocol should help avoid misinterpretation of blood flow asymmetry in the assessment of hand disorders

  5. Dynamic Effect of Rolling Massage on Blood Flow

    Science.gov (United States)

    Chen, Yan-Yan; Yi, Hou-Hui; Li, Hua-Bing; Fang, Hai-Ping

    2009-02-01

    The Chinese traditional medical massage has been used as a natural therapy to eliminate some diseases. Here, the effect of the rolling massage frequency to the blood flow in the blood vessels under the rolling massage manipulation is studied by the lattice Boltzmann simulation. The simulation results show that when the frequency is smaller than or comparable to the pulsatile frequency of the blood flow, the effect on the blood flux by the rolling massage is small. On the contrast, if the frequency is twice or more times of the pulsatile frequency of the blood flow, the blood flux is greatly enhanced and increases linearly with respect to the frequency. Similar behavior has also been observed on the shear stress on the blood vessel walls. The result is helpful for understanding that the rolling massage has the function of promoting the blood circulation and removing the blood stasis.

  6. Effect of fractionated heating on the blood flow in normal tissues.

    Science.gov (United States)

    Lokshina, A M; Song, C W; Rhee, J G; Levitt, S H

    1985-01-01

    The changes in blood flow in the skin and muscle of rat by single, two or six heatings, were measured with the radioactive microsphere method. The blood flow rose continuously during the 2 h heatings at temperatures up to 43.0 degrees C and 44.0 degrees C in the skin and muscle, respectively. When heated at higher temperatures, the blood flow increased and then decreased. When heated twice at 43.5 degrees C for 1 h each, the magnitude of the increase in blood flow by the second heating varied depending on the time interval between the two heatings; e.g., the second heating on the 14th day after the first heating induced an increase in blood flow much greater than that by the first heating. When the heating at 43.5 degrees C for 1 h was repeated at intervals of five days, the second and third heatings were as effective as the first heating in increasing the skin blood flow. In the muscle, the second and third heatings were 2-3-fold more effective than the first heating in raising the blood flow. The heat-induced increase in blood flow in the skin and muscle gradually diminished from the fourth heating. The tissue temperature varied considerably during heating with a water bath at a constant temperature, due probably to the changes in blood flow.

  7. Renal blood flow and metabolism after cold ischaemia

    DEFF Research Database (Denmark)

    Henriksen, J H; Petersen, H K

    1984-01-01

    .01) immediately after re-established perfusion and 36% (P less than 0.02) 30 min later. In one additional patient, who had a short warm ischaemia (8 min), the flow pattern was the same. As arterial pressure remained constant, the reduced RBF signifies an increased renal vascular resistance. Renal O2-uptake......Peroperative measurements of renal blood flow (RBF), renal O2-uptake, and renal venous lactate/pyruvate (L/P) ratio were performed before and after a period of 30-71 min of hypothermic (10-15 degrees C) renal ischaemia in nine patients, undergoing surgery for renal calculi. Before ischaemia, RBF...... and renal venous L/P ratio were almost constant, indicating no significant anaerobic processes being involved in the flow response. None of the patients showed any signs of reactive hyperaemia. It is concluded that hypothermic renal ischaemia may be followed by an increased renal vascular resistance even...

  8. Coupling of porcine bone blood flow and metabolism in high-turnover bone disease measured by [15O]H2O and [18F]fluoride ion positron emission tomography

    International Nuclear Information System (INIS)

    Piert, Morand; Machulla, Hans-Juergen; Stahlschmidt, Anke; Becker, Georg A.; Jahn, Michael; Zittel, Tilman T.

    2002-01-01

    Previously, we identified a parathyroid hormone-related high-turnover bone disease after gastrectomy in mini pigs. Dynamic [ 18 F]fluoride ion positron emission tomography (PET) revealed that bone metabolism was significantly increased, but that bone blood flow derived from permeability-surface area product (PS product)-corrected K 1 values was not. Since bone blood flow and metabolism are coupled in normal bone tissues, we hypothesised that the capillary permeability and/or surface area might be altered in high-turnover bone disease. The ''true'' bone blood flow (f H2O ) was measured in vertebral bodies by dynamic [ 15 O]H 2 O PET, followed by a 120-min dynamic [ 18 F]fluoride ion PET study, 6 months after total gastrectomy (n=5) and compared with results in sham-operated animals (n=5). Estimates for bone blood flow based on PS-corrected K 1 values (f) and the net uptake of fluoride in bone tissue (K i ), representing the bone metabolic activity, were calculated using standard compartmental modelling and non-linear fitting. Gastrectomy was followed by a significant elevation of K i and k 3 (P H2O , f, the single-pass extraction fraction of [ 18 F]fluoride (E) and the volume of distribution (DV) of [ 18 F]fluoride were not significantly different between groups. In both groups, a coupling of the mean f H2O and K i values was found, but the intercept with the y-axis was higher in high-turnover bone disease. It is concluded that in high-turnover bone disease following gastrectomy, the PS product for [ 18 F]fluoride remains unchanged. Therefore, even in high-turnover bone diseases, [ 18 F]fluoride ion PET can provide reliable blood flow estimates (f), as long as a proper PS product correction is applied. The increased bone metabolism in high-turnover bone disease after gastrectomy is mainly related to an up-regulation of the amount of ionic exchange of [ 18 F]fluoride with the bone matrix, while tracer delivery remains unchanged. (orig.)

  9. Coupling of porcine bone blood flow and metabolism in high-turnover bone disease measured by [{sup 15}O]H{sub 2}O and [{sup 18}F]fluoride ion positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Piert, Morand [Nuclear Medicine, Klinikum Rechts der Isar, Technical University of Munich (Germany); Machulla, Hans-Juergen; Stahlschmidt, Anke; Becker, Georg A. [Radiopharmacy Section, PET Center, University of Tuebingen (Germany); Jahn, Michael; Zittel, Tilman T. [Department of Abdominal and Transplantation Surgery, University of Tuebingen (Germany)

    2002-07-01

    Previously, we identified a parathyroid hormone-related high-turnover bone disease after gastrectomy in mini pigs. Dynamic [{sup 18}F]fluoride ion positron emission tomography (PET) revealed that bone metabolism was significantly increased, but that bone blood flow derived from permeability-surface area product (PS product)-corrected K{sub 1} values was not. Since bone blood flow and metabolism are coupled in normal bone tissues, we hypothesised that the capillary permeability and/or surface area might be altered in high-turnover bone disease. The ''true'' bone blood flow (f{sub H2O}) was measured in vertebral bodies by dynamic [{sup 15}O]H{sub 2}O PET, followed by a 120-min dynamic [{sup 18}F]fluoride ion PET study, 6 months after total gastrectomy (n=5) and compared with results in sham-operated animals (n=5). Estimates for bone blood flow based on PS-corrected K{sub 1} values (f) and the net uptake of fluoride in bone tissue (K{sub i}), representing the bone metabolic activity, were calculated using standard compartmental modelling and non-linear fitting. Gastrectomy was followed by a significant elevation of K{sub i} and k{sub 3} (P<0.05), which was mainly caused by an increase of the fraction of bound tracer in tissue (P<0.01). In contrast, f{sub H2O}, f, the single-pass extraction fraction of [{sup 18}F]fluoride (E) and the volume of distribution (DV) of [{sup 18}F]fluoride were not significantly different between groups. In both groups, a coupling of the mean f{sub H2O} and K{sub i} values was found, but the intercept with the y-axis was higher in high-turnover bone disease. It is concluded that in high-turnover bone disease following gastrectomy, the PS product for [{sup 18}F]fluoride remains unchanged. Therefore, even in high-turnover bone diseases, [{sup 18}F]fluoride ion PET can provide reliable blood flow estimates (f), as long as a proper PS product correction is applied. The increased bone metabolism in high-turnover bone disease

  10. In vivo analysis of physiological 3D blood flow of cerebral veins

    Energy Technology Data Exchange (ETDEWEB)

    Schuchardt, Florian; Schroeder, Laure; Baeuerle, Jochen; Harloff, Andreas [University Medical Centre, Department of Neurology, Freiburg (Germany); Anastasopoulos, Constantin [University Medical Center, Department of Neuropaediatrics and Muscle Disorders, Freiburg (Germany); University Medical Centre, Department of Neuroradiology, Freiburg (Germany); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine and McCormick School of Engineering, Chicago, IL (United States); Hennemuth, Anja; Drexl, Johann [Fraunhofer MEVIS, Bremen (Germany); Valdueza, Jose M. [Neurological Center, Segeberger Kliniken, Bad Segeberg (Germany); Mader, Irina [University Medical Centre, Department of Neuroradiology, Freiburg (Germany)

    2015-08-15

    To visualize and quantify physiological blood flow of intracranial veins in vivo using time-resolved, 3D phase-contrast MRI (4D flow MRI), and to test measurement accuracy. Fifteen healthy volunteers underwent repeated ECG-triggered 4D flow MRI (3 Tesla, 32-channel head coil). Intracranial venous blood flow was analysed using dedicated software allowing for blood flow visualization and quantification in analysis planes at the superior sagittal, straight, and transverse sinuses. MRI was evaluated for intra- and inter-observer agreement and scan-rescan reproducibility. Measurements of the transverse sinuses were compared with transcranial two-dimensional duplex ultrasound. Visualization of 3D blood flow within cerebral sinuses was feasible in 100 % and within at least one deep cerebral vein in 87 % of the volunteers. Blood flow velocity/volume increased along the superior sagittal sinus and was lower in the left compared to the right transverse sinus. Intra- and inter-observer reliability and reproducibility of blood flow velocity (mean difference 0.01/0.02/0.02 m/s) and volume (mean difference 0.0002/-0.0003/0.00003 l/s) were good to excellent. High/low velocities were more pronounced (8 % overestimation/9 % underestimation) in MRI compared to ultrasound. Four-dimensional flow MRI reliably visualizes and quantifies three-dimensional cerebral venous blood flow in vivo and is promising for studies in patients with sinus thrombosis and related diseases. (orig.)

  11. Effects of aminophylline on behaviorally induced coronary blood flow increases.

    Science.gov (United States)

    Billman, G E

    1987-09-01

    It has been proposed that adenosine is a metabolic vasodilator that matches myocardial oxygen supply to demand by regulating coronary blood flow. In the present study, the adenosine antagonist aminophylline (Am) was used to evaluate the role adenosine plays in the coronary blood flow increase elicited by a controlled aversive stress, namely, classical aversive conditioning (a 30-s tone reinforced with a 1-s shock). Fifteen mongrel dogs were chronically instrumented to measure left circumflex coronary blood flow (CBF), left ventricular pressure (LVP), and heart rate. Am significantly (P greater than 0.01) attenuated the CBF response to the aversive stress without affecting the prestress levels (pre-Am control 40.9 +/- 2.4, peak 64.6 +/- 3.3 ml/min; post-Am control 41.7 +/- 2.2, peak 55.0 +/- 2.5 ml/min). The maximal CBF increase was reduced by 38.9 +/- 6.7% when compared with the control (no drug) condition. In a similar manner, neither heart rate nor LVP was affected by Am. However, Am significantly increased prestress level of first derivative of left ventricular pressure with reference to time [LV dP/dt] (pre-Am control 3,793.5 +/- 289.8 and Am 4,599.6 +/- 331.2 mmHg/s, respectively). These data suggest that adenosine contributes significantly to the regulation of CBF during a controlled emotional stress.

  12. Cerebral blood flow is reduced in patients with sepsis syndrome

    International Nuclear Information System (INIS)

    Bowton, D.L.; Bertels, N.H.; Prough, D.S.; Stump, D.A.

    1989-01-01

    The relationship between sepsis-induced CNS dysfunction and changes in brain blood flow remains unknown, and animal studies examining the influence of sepsis on cerebral blood flow (CBF) do not satisfactorily address that relationship. We measured CBF and cerebrovascular reactivity to CO 2 in nine patients with sepsis syndrome using the 133 Xe clearance technique. Mean CBF was 29.6 +/- 15.8 (SD) ml/100 g.min, significantly lower than the normal age-matched value in this laboratory of 44.9 +/- 6.2 ml/100 g.min (p less than .02). This depression did not correlate with changes in mean arterial pressure. Despite the reduction in CBF, the specific reactivity of the cerebral vasculature to changes in CO 2 was normal, 1.3 +/- 0.9 ml/100 g.min/mm Hg. Brain blood flow is reduced in septic humans; the contribution of this reduction to the metabolic and functional changes observed in sepsis requires further study

  13. Radiotracer techniques for measuring fluid flow and calibrating flow meters

    International Nuclear Information System (INIS)

    Cooper, E.L.

    1987-08-01

    Radiotracer techniques can be used to measure accurately both gas and liquid flow rates under operating conditions in a wide range of flow systems. They are ideally suited for calibrating flow meters as well as for measuring unmetered flows in industrial plants. Applications of these techniques range from measuring the flows of fuels and process fluids for energy and mass balance studies to measuring the flows of liquid and airborne effluents for pollution control. This report describes the various radiotracer techniques which can be used to measure fluid flows. The range of application and inherent accuracy of each technique is discussed

  14. Quantitative assessment of limb blood flow using Tc-99m labeled red blood cells. Radionuclide venous occlusion plethysmography (RAVOP)

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Kazuo; Shougase, Takashi; Kawamura, Naoyuki; Tsukamoto, Eriko; Nakada, Kunihiro; Sakuma, Makoto; Furudate, Masayori

    1987-10-01

    A quantitative assessment of limb blood flow using a non-diffusible radioindicator, Tc-99m labeled red blood cells, was reported. This was an application of venous occlusion plethysmography using radionuclide which was originally proposed by M. Fukuoka et al. The peripheral blood flow (mean +- s.e.) of 30 legs in a normal control group was 1.87 +- 0.08 ml/100 ml/min. In heart diseases (46 legs), it was 1.49 +- 0.13 ml/100 ml/min. The limb blood flow between a control group and heart diseases was statistically significant (p < 0.01) in the t-test. The peripheral blood flow at rest between diseased legs and normal legs in occlusive arterial disorders was also statistically significant (p < 0.01) in a paired t-test. RAVOP was done after the completion of objective studies such as radionuclide angiography or ventriculography. Technique and calculation of a blood flow were very easy and simple. RAVOP study which was originally proposed by Fukuoka et al. was reappraised to be hopeful for quantitative measurement of limb blood flow as a non-invasive technique using Tc-99m labeled red blood cells.

  15. Measurement of regional cerebral blood flow using one-point arterial blood sampling and microsphere model with 123I-IMP. Correction of one-point arterial sampling count by whole brain count ratio

    International Nuclear Information System (INIS)

    Makino, Kenichi; Masuda, Yasuhiko; Gotoh, Satoshi

    1998-01-01

    The experimental subjects were 189 patients with cerebrovascular disorders. 123 I-IMP, 222 MBq, was administered by intravenous infusion. Continuous arterial blood sampling was carried out for 5 minutes, and arterial blood was also sampled once at 5 minutes after 123 I-IMP administration. Then the whole blood count of the one-point arterial sampling was compared with the octanol-extracted count of the continuous arterial sampling. A positive correlation was found between the two values. The ratio of the continuous sampling octanol-extracted count (OC) to the one-point sampling whole blood count (TC5) was compared with the whole brain count ratio (5:29 ratio, Cn) using 1-minute planar SPECT images, centering on 5 and 29 minutes after 123 I-IMP administration. Correlation was found between the two values. The following relationship was shown from the correlation equation. OC/TC5=0.390969 x Cn-0.08924. Based on this correlation equation, we calculated the theoretical continuous arterial sampling octanol-extracted count (COC). COC=TC5 x (0.390969 x Cn-0.08924). There was good correlation between the value calculated with this equation and the actually measured value. The coefficient improved to r=0.94 from the r=0.87 obtained before using the 5:29 ratio for correction. For 23 of these 189 cases, another one-point arterial sampling was carried out at 6, 7, 8, 9 and 10 minutes after the administration of 123 I-IMP. The correlation coefficient was also improved for these other point samplings when this correction method using the 5:29 ratio was applied. It was concluded that it is possible to obtain highly accurate input functions, i.e., calculated continuous arterial sampling octanol-extracted counts, using one-point arterial sampling whole blood counts by performing correction using the 5:29 ratio. (K.H.)

  16. Interscapular brown adipose tissue blood flow in the rat. Determination with 133xenon clearance compared to the microsphere method

    DEFF Research Database (Denmark)

    Astrup, A; Bülow, J; Madsen, J

    1984-01-01

    The xenon clearance method was adapted to continuous measurement of interscapular brown adipose tissue (ISBAT) blood flow in anesthetized rats. The ISBAT-blood partition coefficient for xenon was determined to 3.6 ml X g-1. The blood flow values obtained by Xe clearance were compared with flow...... values obtained concomitantly by the microsphere technique in 17 cold acclimated rats, at ISBAT blood flows between 0.1 and 6 ml X g-1 X min-1. Variations in blood flows were obtained by infusion of noradrenaline at different rates. The blood flow values obtained from the xenon clearance method showed...... a close correlation to the blood flow values determined with microspheres. Y = 0.98. X + 0.15 (r = 0.96, P less than 0.001). The Xe clearance method has the advantages compared to the microsphere technique that it permits continuous monitoring of the blood flow and does not require the sacrifice...

  17. Blood flow velocity imaging of malignant melanoma by micro multipoint laser Doppler velocimetry

    Science.gov (United States)

    Ishida, H.; Andoh, T.; Akiguchi, S.; Shirakawa, H.; Kobayashi, D.; Kuraishi, Y.; Hachiga, T.

    2010-09-01

    We have developed a laser Doppler velocimeter to measure blood flow, the micromultipoint laser Doppler velocimeter (μ-MLDV). This equipment can measure absolute velocity and, based on this, can display the course of blood vessels. In this study, we attempted to perform blood flow velocity imaging of malignant melanoma transplanted to the mouse ear. We found that blood flow velocity of the formed blood vessels originating in the melanoma was much greater than that of the capillary vessels in normal skin. Furthermore, the form of the tumor was clearly visible from the blood flow velocity image. These experimental results suggest that μ-MLDV has potential as a diagnostic method for distinguishing benign nevi from malignant melanomas.

  18. Using Crossflow for Flow Measurements and Flow Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gurevich, A.; Chudnovsky, L.; Lopeza, A. [Advanced Measurement and Analysis Group Inc., Ontario (Canada); Park, M. H. [Sungjin Nuclear Engineering Co., Ltd., Gyeongju (Korea, Republic of)

    2016-10-15

    Ultrasonic Cross Correlation Flow Measurements are based on a flow measurement method that is based on measuring the transport time of turbulent structures. The cross correlation flow meter CROSSFLOW is designed and manufactured by Advanced Measurement and Analysis Group Inc. (AMAG), and is used around the world for various flow measurements. Particularly, CROSSFLOW has been used for boiler feedwater flow measurements, including Measurement Uncertainty Recovery (MUR) reactor power uprate in 14 nuclear reactors in the United States and in Europe. More than 100 CROSSFLOW transducers are currently installed in CANDU reactors around the world, including Wolsung NPP in Korea, for flow verification in ShutDown System (SDS) channels. Other CROSSFLOW applications include reactor coolant gross flow measurements, reactor channel flow measurements in all channels in CANDU reactors, boiler blowdown flow measurement, and service water flow measurement. Cross correlation flow measurement is a robust ultrasonic flow measurement tool used in nuclear power plants around the world for various applications. Mathematical modeling of the CROSSFLOW agrees well with laboratory test results and can be used as a tool in determining the effect of flow conditions on CROSSFLOW output and on designing and optimizing laboratory testing, in order to ensure traceability of field flow measurements to laboratory testing within desirable uncertainty.

  19. Left coronary arterial blood flow: Noninvasive detection by Doppler US

    International Nuclear Information System (INIS)

    Gramiak, R.; Holen, J.; Moss, A.J.; Gutierrez, O.H.; Picone, A.L.; Roe, S.A.

    1986-01-01

    Continuous wave (CW) and pulsed Doppler ultrasound studies with spectral analysis were used to detect the left coronary arterial blood flow in patients who were undergoing routine echocardiography. The pulmonary artery is a stable ultrasonic landmark from which detection of the blood flow can be effected. The left coronary artery can be distinguished by its blood flow toward the cardiac apex and by specific, functional flow features. Flow patterns vary among the left main, circumflex, and anterior descending arteries; patterns also vary with respiration cycles. In the present study, coronary arterial blood flow was detected in 58 of 70 patients (83%). Findings were validated by selectively injecting an agitated saline contrast medium into the left coronary artery and, in another study, by comparing human Doppler phasic flow waveforms with electromagnetic flowmeter recordings obtained in dogs

  20. Sympathetic reflex control of blood flow in human peripheral tissues

    DEFF Research Database (Denmark)

    Henriksen, O

    1991-01-01

    sympathetic vasoconstrictor reflexes are blocked. Blood flow has been measure by the local 133Xe-technique. The results indicate the presence of spinal as well as supraspinal sympathetic vasoconstrictor reflexes to human peripheral tissues. Especially is emphasized the presence of a local sympathetic veno......Sympathetic vasoconstrictor reflexes are essential for the maintenance of arterial blood pressure in upright position. It has been generally believed that supraspinal sympathetic vasoconstrictor reflexes elicited by changes in baroreceptor activity play an important role. Recent studies on human...... skeletal muscle, cutaneous and subcutaneous tissues of the limbs indicate that the situation is more complex. Measurements have been carried out during acute as well as chronic sympathetic denervation. Spinal sympathetic reflex mechanisms have been evaluated in tetraplegic patients, where supraspinal...

  1. Effect of a single injection of gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) on testicular blood flow measured by color doppler ultrasonography in male Shiba goats.

    Science.gov (United States)

    Samir, Haney; Sasaki, Kazuaki; Ahmed, Eman; Karen, Aly; Nagaoka, Kentaro; El Sayed, Mohamed; Taya, Kazuyoshi; Watanabe, Gen

    2015-05-01

    Although color Doppler ultrasonography has been used to evaluate testicular blood flow in many species, very little has been done in goat. Eight male Shiba goats were exposed to a single intramuscular injection of either gonadotropin-releasing hormone (GnRH group; 1 µg/kg BW) or human chorionic gonadotropin (hCG group; 25 IU/kg BW). Plasma testosterone (T), estradiol (E2) and inhibin (INH) were measured just before (0 hr) and at different intervals post injection by radioimmunoassay. Testis volume (TV) and Doppler indices, such as resistive index (RI) and pulsatility index (PI) of the supratesticular artery, were measured by B-mode and color Doppler ultrasonography, respectively. The results indicated an increase in testicular blood flow in both groups, as RI and PI decreased significantly (P<0.05), but this increase was significant higher and earlier in hCG group (1 hr) than in the GnRH group (2 hr). A high correlation was found for RI and PI with both T (RI, r= -0.862; PI, r= -0.707) and INH in the GnRH group (RI, r=0.661; PI, r=0.701). However, a significant (P<0.05) correlation was found between E2 and both RI (r= -0.610) and PI (r= -0.763) in hCG group. In addition, TV significantly increased and was highly correlated with RI in both groups (GnRH, r= -0.718; hCG, r= -0.779). In conclusion, hCG and GnRH may improve testicular blood flow and TV in Shiba goats.

  2. Dynamic modeling of renal blood flow in Dahl hypertensive and normotensive rats

    DEFF Research Database (Denmark)

    Knudsen, Torben; Elmer, Henrik; Knudsen, Morten H

    2004-01-01

    A method is proposed in this paper which allows characterization of renal autoregulatory dynamics and efficiency using quantitative mathematical methods. Based on data from rat experiments, where arterial blood pressure and renal blood flow are measured, a quantitative model for renal blood flow ...... describe myogenic responses and tubuloglomerular feedback responses separately. The method is applied to data from normo- and hypertensive Dahl rats, and a discriminator that separates data from normotensive Dahl R rats and hypertensive Dahl S rats is constructed....

  3. Peak-counts blood flow model-errors and limitations

    International Nuclear Information System (INIS)

    Mullani, N.A.; Marani, S.K.; Ekas, R.D.; Gould, K.L.

    1984-01-01

    The peak-counts model has several advantages, but its use may be limited due to the condition that the venous egress may not be negligible at the time of peak-counts. Consequently, blood flow measurements by the peak-counts model will depend on the bolus size, bolus duration, and the minimum transit time of the bolus through the region of interest. The effect of bolus size on the measurement of extraction fraction and blood flow was evaluated by injecting 1 to 30ml of rubidium chloride in the femoral vein of a dog and measuring the myocardial activity with a beta probe over the heart. Regional blood flow measurements were not found to vary with bolus sizes up to 30ml. The effect of bolus duration was studied by injecting a 10cc bolus of tracer at different speeds in the femoral vein of a dog. All intravenous injections undergo a broadening of the bolus duration due to the transit time of the tracer through the lungs and the heart. This transit time was found to range from 4-6 second FWHM and dominates the duration of the bolus to the myocardium for up to 3 second injections. A computer simulation has been carried out in which the different parameters of delay time, extraction fraction, and bolus duration can be changed to assess the errors in the peak-counts model. The results of the simulations show that the error will be greatest for short transit time delays and for low extraction fractions

  4. Resistance exercise with different volumes: blood pressure response and forearm blood flow in the hypertensive elderly

    Directory of Open Access Journals (Sweden)

    Brito AF

    2014-12-01

    Full Text Available Aline de Freitas Brito,1 Caio Victor Coutinho de Oliveira,2 Maria do Socorro Brasileiro-Santos,1 Amilton da Cruz Santos1 1Physical Education Department, 2Research Laboratory for Physical Training Applied to Performance and Health, Federal University of Paraíba, João Pessoa, Brazil Background: The purpose of this study was to evaluate the effect of two sessions of resistance exercise with different volumes on post-exercise hypotension, forearm blood flow, and forearm vascular resistance in hypertensive elderly subjects.Methods: The study was conducted with ten hypertensive elderly (65±3 years, 28.7±3 kg/m2 subjected to three experimental sessions, ie, a control session, exercise with a set (S1, and exercise with three sets (S3. For each session, the subjects were evaluated before and after intervention. In the pre-intervention period, blood pressure, forearm blood flow, and forearm vascular resistance were measured after 10 minutes of rest in the supine position. Thereafter, the subjects were taken to the gym to perform their exercise sessions or remained at rest during the same time period. Both S1 and S3 comprised a set of ten repetitions of ten exercises, with an interval of 90 seconds between exercises. Subsequently, the measurements were again performed at 10, 30, 50, 70, and 90 minutes of recovery (post-intervention in the supine position.Results: Post-exercise hypotension was greater in S3 than in S1 (systolic blood pressure, −26.5±4.2 mmHg versus −17.9±4.7 mmHg; diastolic blood pressure, −13.8±4.9 mmHg versus −7.7±5 mmHg, P<0.05. Similarly, forearm blood flow and forearm vascular resistance changed significantly in both sessions with an increase and decrease, respectively, that was more evident in S3 than in S1 (P<0.05.Conclusion: Resistance exercises with higher volume were more effective in causing post-exercise hypotension, being accompanied by an increase in forearm blood flow and a reduction of forearm vascular

  5. Effect of hindlimb unweighting on tissue blood flow in the rat

    Science.gov (United States)

    Mcdonald, K. S.; Delp, M. D.; Fitts, R. H.

    1992-01-01

    This study characterized distribution of blood flow in the rat during hindlimb unweighting (HU), and post-HU standing and exercise. The relationship between reduced hindlimb blood flow and the previously observed elevation in anaerobic metabolism observed with contractile activity in the atrophied soleus muscle was examined (Witzmann et al., 1992). Blood flow was measured during unweighting, normal standing, and running on a treadmill (15 m/min), after 15 days of HU or cage control. For another group blood flow was measured during preexercise treadmill standing and treadmill running. During unweighting, PE standing, and running no difference in soleus blood flow was observed between groups. Muscles composed mainly of fast twitch glycolytic fibers received greater blood flow during chronic unweighting. With exercise blood flow to visceral organs was reduced in control animals, a similar change was not seen in 15 day HU rats. These changes suggest a reduction in the ability of the sympathetic nervous system to distribute cardiac output after chronic HU. A reduction in blood flow to the soleus during exercise was not observed after HU and so does not explain the increased dependence of the atrophied soleus on anerobic energy production during contractile activity.

  6. Increased coronary collateral blood flow. A possible mechanism of action for betahistine-HCl.

    Science.gov (United States)

    Terracio, L; Kubicek, W G

    1979-01-01

    beta-Histine-HCl has been shown to be effective in modifying the size of developing myocardial infarcts. In the present study the hypothesis that beta-histine increases the flow of blood through collateral channels and thus supplies blood to ligated areas of the myocardium was investigated in the dog. The methods used were measurement of retrograde coronary blood flow and angiography after coronary artery ligation. beta-Histine administration for 6 h increased retrograde blood flow 68.2--91.0% over controls. Coronary angiography demonstrated the existence of collateral channels 200--400 micrometer in diameter within the myocardium after ligation and 4 h of beta-histine administration.

  7. Regional Distribution of Cerebral Blood Flow in childhood Measured by '99mTc-HMPAO SPECT: Reference Values of Semiquantitative Indices and Effect of Age

    International Nuclear Information System (INIS)

    Kim, Sang Eun; Lee, Dong Soo; Chung, June Key

    1991-01-01

    Regional cerebral blood flow (rCBF) was evaluated in 12 children ranging in age from 2.7 to 10.0 yr using 99m Tc-HMPAO SPECT. For quantitative analysis, 13 pairs of homologous regions of interest (ROIs) were created on three attenuation-corrected 18,8 mm thick transverse slices matching the cerebral cortical regions, deep gray matter, cerebellar hemisphere, and vascular territories, and the semiquantitative indices including 'right to left ratio [(mean count/voxel of homologous right ROI) /(mean count/voxel of homologous left ROI)] and regional index '(RI) [(mean count/voxel of a ROI)/(mean count/voxel of all ROIs of each hemisphere)] were calculated. Mean values of right to left ratios of homologous regions ranged from 0.984 to 1.028 in children under 5 yr (group 1) and from 0.982 to 1.012 in children between 5 and 10 yr (group 2), and the mean value ±2 S.D. for each region did not exceed 11%. and 12% in group 1 and group 2, respective]y. There were no statistically significant differences between the RIs of the homologous right and left regions. Significant differences of RIs were found both between vascular regions (p<0,0005 for group 1, and p=0,0001 for group 2) and between regions of cerebral cortices (p<0,0005 for group 1, and p<0,005 for group 2) with a relatively high value in the occipital cortex and the lower values in the cerebellum and deep gray matter among the regions of cerebral cortices in both groups. There were no significant differences between the Rls of corresponding regions of group 1 and group 2, except a significantly higher value of right deep gray matter in group 2 than in group 1 (p=0.0301). The RIs of the superior frontal cortex and deep gray matter showed to be positively correlated with age (superior frontal cortex; right: rs=0.5254, p=0.0814, left: rs=0.5919, p=0.0496/deep gray matter; right: rs=0.8246, p=0.0062, left: rs=0.6266, p=0,0377). The results suggest that the rCBF pattern of children approaches that of adults in an occipito

  8. Glial and neuronal control of brain blood flow

    DEFF Research Database (Denmark)

    Attwell, David; Buchan, Alastair M; Charpak, Serge

    2010-01-01

    Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...

  9. Effect of prolonged hypokinesia on tissue blood flow

    Science.gov (United States)

    Levites, Z. P.; Fedotova, V. F.

    1979-01-01

    The influence of hypokinesia on the blood flow in the tissues of rabbits was studied. Motor activity of animals was restricted during 90 days and blood flow recorded through resorption rate of NaI-131. Perfusion of tissues under the influence of hypokinesia was found to be reduced.

  10. Relation of retinal blood flow and retinal oxygen extraction during stimulation with diffuse luminance flicker

    Science.gov (United States)

    Palkovits, Stefan; Lasta, Michael; Told, Reinhard; Schmidl, Doreen; Werkmeister, René; Cherecheanu, Alina Popa; Garhöfer, Gerhard; Schmetterer, Leopold

    2015-01-01

    Cerebral and retinal blood flow are dependent on local neuronal activity. Several studies quantified the increase in cerebral blood flow and oxygen consumption during activity. In the present study we investigated the relation between changes in retinal blood flow and oxygen extraction during stimulation with diffuse luminance flicker and the influence of breathing gas mixtures with different fractions of O2 (FiO2; 100% 15% and 12%). Twenty-four healthy subjects were included. Retinal blood flow was studied by combining measurement of vessel diameters using the Dynamic Vessel Analyser with measurements of blood velocity using laser Doppler velocimetry. Oxygen saturation was measured using spectroscopic reflectometry and oxygen extraction was calculated. Flicker stimulation increased retinal blood flow (57.7 ± 17.8%) and oxygen extraction (34.6 ± 24.1%; p flicker–induced retinal haemodynamic changes. The present study indicates that at a comparable increase in blood flow the increase in oxygen extraction in the retina is larger than in the brain. During systemic hyperoxia the blood flow and oxygen extraction responses to neural stimulation are augmented. The underlying mechanism is unknown. PMID:26672758

  11. Longitudinal optical monitoring of blood flow in breast tumors during neoadjuvant chemotherapy

    Science.gov (United States)

    Cochran, J. M.; Chung, S. H.; Leproux, A.; Baker, W. B.; Busch, D. R.; DeMichele, A. M.; Tchou, J.; Tromberg, B. J.; Yodh, A. G.

    2017-06-01

    We measure tissue blood flow markers in breast tumors during neoadjuvant chemotherapy and investigate their correlation to pathologic complete response in a pilot longitudinal patient study (n  =  4). Tumor blood flow is quantified optically by diffuse correlation spectroscopy (DCS), and tissue optical properties, blood oxygen saturation, and total hemoglobin concentration are derived from concurrent diffuse optical spectroscopic imaging (DOSI). The study represents the first longitudinal DCS measurement of neoadjuvant chemotherapy in humans over the entire course of treatment; it therefore offers a first correlation between DCS flow indices and pathologic complete response. The use of absolute optical properties measured by DOSI facilitates significant improvement of DCS blood flow calculation, which typically assumes optical properties based on literature values. Additionally, the combination of the DCS blood flow index and the tissue oxygen saturation from DOSI permits investigation of tissue oxygen metabolism. Pilot results from four patients suggest that lower blood flow in the lesion-bearing breast is correlated with pathologic complete response. Both absolute lesion blood flow and lesion flow relative to the contralateral breast exhibit potential for characterization of pathological response. This initial demonstration of the combined optical approach for chemotherapy monitoring provides incentive for more comprehensive studies in the future and can help power those investigations.

  12. Carbon monoxide and pancreatic islet blood flow in the rat: inhibition of haem oxygenase does not affect islet blood perfusion.

    Science.gov (United States)

    Carlsson, P-O; Bodin, B; Andersson, A; Jansson, L

    2006-01-01

    To determine whether carbon monoxide, a known gaseous vasorelaxator, affects pancreatic islet blood flow in rats. Sprague-Dawley rats were anaesthetized with thiobutabarbital and injected intravenously with the haem oxygenase inhibitor tin-protoporphyrin IX dichloride (SnPP; 4, 10 or 20 mg/kg body-weight). After 15 min, blood flow measurements were performed using a microsphere technique. There was a slight increase in mean arterial blood pressure with the highest dose of SnPP. No effects on total pancreatic, islet, duodenal, colonic, renal or adrenal blood flow were seen with any of the applied doses. The findings of this study suggest that the haem oxygenase-carbon monoxide system is likely to be of limited importance in the regulation of blood perfusion to the pancreas, the islets of Langerhans or any of the other studied organs.

  13. Prediction of Anomalous Blood Viscosity in Confined Shear Flow

    NARCIS (Netherlands)

    Thiébaud, Marine; Shen, Z.; Shen, Zaiyi; Harting, Jens Dieter Rolf; Misbah, Chaouqi

    2014-01-01

    Red blood cells play a major role in body metabolism by supplying oxygen from the microvasculature to different organs and tissues. Understanding blood flow properties in microcirculation is an essential step towards elucidating fundamental and practical issues. Numerical simulations of a blood

  14. Thermographic venous blood flow characterization with external cooling stimulation

    Science.gov (United States)

    Saxena, Ashish; Ng, E. Y. K.; Raman, Vignesh

    2018-05-01

    Experimental characterization of blood flow in a human forearm is done with the application of continuous external cooling based active thermography method. Qualitative and quantitative detection of the blood vessel in a thermal image is done, along with the evaluation of blood vessel diameter, blood flow direction, and velocity in the target blood vessel. Subtraction based image manipulation is performed to enhance the feature contrast of the thermal image acquired after the removal of external cooling. To demonstrate the effect of occlusion diseases (obstruction), an external cuff based occlusion is applied after the removal of cooling and its effect on the skin rewarming is studied. Using external cooling, a transit time method based blood flow velocity estimation is done. From the results obtained, it is evident that an external cooling based active thermography method can be used to develop a diagnosis tool for superficial blood vessel diseases.

  15. Usage of CO2 microbubbles as flow-tracing contrast media in X-ray dynamic imaging of blood flows.

    Science.gov (United States)

    Lee, Sang Joon; Park, Han Wook; Jung, Sung Yong

    2014-09-01

    X-ray imaging techniques have been employed to visualize various biofluid flow phenomena in a non-destructive manner. X-ray particle image velocimetry (PIV) was developed to measure velocity fields of blood flows to obtain hemodynamic information. A time-resolved X-ray PIV technique that is capable of measuring the velocity fields of blood flows under real physiological conditions was recently developed. However, technical limitations still remained in the measurement of blood flows with high image contrast and sufficient biocapability. In this study, CO2 microbubbles as flow-tracing contrast media for X-ray PIV measurements of biofluid flows was developed. Human serum albumin and CO2 gas were mechanically agitated to fabricate CO2 microbubbles. The optimal fabricating conditions of CO2 microbubbles were found by comparing the size and amount of microbubbles fabricated under various operating conditions. The average size and quantity of CO2 microbubbles were measured by using a synchrotron X-ray imaging technique with a high spatial resolution. The quantity and size of the fabricated microbubbles decrease with increasing speed and operation time of the mechanical agitation. The feasibility of CO2 microbubbles as a flow-tracing contrast media was checked for a 40% hematocrit blood flow. Particle images of the blood flow were consecutively captured by the time-resolved X-ray PIV system to obtain velocity field information of the flow. The experimental results were compared with a theoretically amassed velocity profile. Results show that the CO2 microbubbles can be used as effective flow-tracing contrast media in X-ray PIV experiments.

  16. Chronic impairment of leg muscle blood flow following cardiac catheterization in childhood

    International Nuclear Information System (INIS)

    Skovranek, J.; Samanek, M.

    1979-01-01

    In 99 patients with congenital heart defects or chronic respiratory disease without clinical symptoms of disturbances in peripheral circulation, resting and maximal blood flow in the anterior tibial muscle of both extremities were investigated 2.7 yrs (average) after cardiac catheterization. The method used involved 133 Xe clearance. Resting blood flow was normal and no difference could be demonstrated between the extremity originally used for catheterization and the contralateral control extremity. No disturbance in maximal blood flow could be proved in the extremity used for catheterization by the venous route only. Maximal blood flow was significantly lower in that extremity where the femoral artery had been catheterized or cannulated for pressure measurement and blood sampling. The disturbance in maximal flow was shown regardless of whether the arterial catheterization involved the Seldinger percutaneous technique, arteriotomy, or mere cannulation of the femoral artery. The values in the involved extremity did not differ significantly from the values in a healthy population

  17. Basic taste stimuli elicit unique responses in facial skin blood flow.

    Directory of Open Access Journals (Sweden)

    Hideaki Kashima

    Full Text Available Facial expression changes characteristically with the emotions induced by basic tastes in humans. We tested the hypothesis that the five basic tastes also elicit unique responses in facial skin blood flow. Facial skin blood flow was measured using laser speckle flowgraphy in 16 healthy subjects before and during the application of basic taste stimuli in the oral cavity for 20 s. The skin blood flow in the eyelid increased in response to sweet and umami taste stimuli, while that in the nose decreased in response to a bitter stimulus. There was a significant correlation between the subjective hedonic scores accompanying these taste stimuli and the above changes in skin blood flow. These results demonstrate that sweet, umami, and bitter tastes induce unique changes in facial skin blood flow that reflect subjective hedonic scores.

  18. Decreased cerebral blood flow after administration of sodium bicarbonate in the distressed newborn infant

    DEFF Research Database (Denmark)

    Lou, H C; Lassen, N A; Fris-Hansen, B

    1978-01-01

    In the course of our studies on cerebral blood flow in newborn infants, we have observed a striking depressing effect of sodium bicarbonate infusion on cerebral blood flow which in some cases may severely aggravate cerebral ischemia. We measured cerebral blood flow before and after the treatment...... with 1 to 8 meqs of sodium bicarbonate in seven distressed newborn infants. The 133 Xe clearance technique was used. The results showed in six of the seven cases a decrease in cerebral blood flow, which in most cases was reduced to 14 to 22 ml/100 g/min, which is about half the value prior...... to the bicarbonate infusion. In one case an extreme reduction occurred: cerebral blood flow was reduced to 3 ml/100 g/min, well below the level compatible with tissue survival. The results are discussed with regard to the optimal treatment of the acidotic newborn....

  19. Cycloid psychosis: regional cerebral blood flow correlates of a psychotic episode.

    Science.gov (United States)

    Warkentin, S; Nilsson, A; Karlson, S; Risberg, J; Franze'n, G; Gustafson, L

    1992-01-01

    Eight patients meeting Leonhard's criteria for cycloid psychosis were investigated on repeated occasions during a psychotic episode, with regional cerebral blood flow measurements and clinical ratings. The results showed that, at admission to the hospital, when the patients were clinically exacerbated, the mean hemispheric blood flow was significantly elevated compared with values from a normal control group. The hemispheric blood flow level covaried significantly with the degree of clinical symptoms, such that the more elevated the cortical blood flow was, the more behaviorally disturbed was the patient. At discharge from the hospital, the patients had no residual symptoms and the cortical blood flow was normal. These findings differ distinctly from those commonly made in other psychoses, such as schizophrenia.

  20. Decreased cerebral blood flow after administration of sodium bicarbonate in the distressed newborn infant

    DEFF Research Database (Denmark)

    Lou, H C; Lassen, N A; Fris-Hansen, B

    1978-01-01

    with 1 to 8 meqs of sodium bicarbonate in seven distressed newborn infants. The 133 Xe clearance technique was used. The results showed in six of the seven cases a decrease in cerebral blood flow, which in most cases was reduced to 14 to 22 ml/100 g/min, which is about half the value prior......In the course of our studies on cerebral blood flow in newborn infants, we have observed a striking depressing effect of sodium bicarbonate infusion on cerebral blood flow which in some cases may severely aggravate cerebral ischemia. We measured cerebral blood flow before and after the treatment...... to the bicarbonate infusion. In one case an extreme reduction occurred: cerebral blood flow was reduced to 3 ml/100 g/min, well below the level compatible with tissue survival. The results are discussed with regard to the optimal treatment of the acidotic newborn....

  1. CALF BLOOD-FLOW AND POSTURE - DOPPLER ULTRASOUND CALIBRATED BY PLETHYSMOGRAPHY

    NARCIS (Netherlands)

    VANLEEUWEN, BE; LUBBERS, J; BARENDSEN, GJ; DEPATER, L

    A procedure was developed that enables measurement of rapid variations in calf blood flow during voluntary rhythmic contraction of the calf muscles in supine, sitting, and standing positions. During the exercise, maximum blood velocity is measured by Doppler ultrasound equipment in the popliteal

  2. Blood flow patterns during incremental and steady-state aerobic exercise.

    Science.gov (United States)

    Coovert, Daniel; Evans, LeVisa D; Jarrett, Steven; Lima, Carla; Lima, Natalia; Gurovich, Alvaro N

    2017-05-30

    Endothelial shear stress (ESS) is a physiological stimulus for vascular homeostasis, highly dependent on blood flow patterns. Exercise-induced ESS might be beneficial on vascular health. However, it is unclear what type of ESS aerobic exercise (AX) produces. The aims of this study are to characterize exercise-induced blood flow patterns during incremental and steady-state AX. We expect blood flow pattern during exercise will be intensity-dependent and bidirectional. Six college-aged students (2 males and 4 females) were recruited to perform 2 exercise tests on cycleergometer. First, an 8-12-min incremental test (Test 1) where oxygen uptake (VO2), heart rate (HR), blood pressure (BP), and blood lactate (La) were measured at rest and after each 2-min step. Then, at least 48-hr. after the first test, a 3-step steady state exercise test (Test 2) was performed measuring VO2, HR, BP, and La. The three steps were performed at the following exercise intensities according to La: 0-2 mmol/L, 2-4 mmol/L, and 4-6 mmol/L. During both tests, blood flow patterns were determined by high-definition ultrasound and Doppler on the brachial artery. These measurements allowed to determine blood flow velocities and directions during exercise. On Test 1 VO2, HR, BP, La, and antegrade blood flow velocity significantly increased in an intensity-dependent manner (repeated measures ANOVA, pblood flow velocity did not significantly change during Test 1. On Test 2 all the previous variables significantly increased in an intensity-dependent manner (repeated measures ANOVA, pblood flow patterns during incremental and steady-state exercises include both antegrade and retrograde blood flows.

  3. Intermittent blood flow restriction does not reduce atrophy following anterior cruciate ligament reconstruction

    Directory of Open Access Journals (Sweden)

    Erik Iversen

    2016-03-01

    Conclusion: In conflict with other studies using a similar protocol, application of blood flow restriction the first 14 days after ACL reconstruction did not reduce quadriceps ACSA muscle atrophy measured by MR in a population of athletes.

  4. Measurement in multiphase reacting flows

    Science.gov (United States)

    Chigier, N. A.

    1979-01-01

    A survey is presented of diagnostic techniques and measurements made in multiphase reacting flows. The special problems encountered by the presence of liquid droplets, soot and solid particles in high temperature chemically reacting turbulent environments are outlined. The principal measurement techniques that have been tested in spray flames are spark photography, laser anemometry, thermocouples and suction probes. Spark photography provides measurement of drop size, drop size distribution, drop velocity, and angle of flight. Photographs are analysed automatically by image analysers. Photographic techniques are reliable, inexpensive and proved. Laser anemometers have been developed for simultaneous measurement of velocity and size of individual particles in sprays under conditions of vaporization and combustion. Particle/gas velocity differentials, particle Reynolds numbers, local drag coefficients and direct measurement of vaporization rates can be made by laser anemometry. Gas temperature in sprays is determined by direct in situ measurement of time constants immediately prior to measurement with compensation and signal analysis by micro-processors. Gas concentration is measured by suction probes and gas phase chromatography. Measurements of particle size, particle velocity, gas temperature, and gas concentration made in airblast and pressure atomised liquid spray flames are presented.

  5. Differences in displayed pump flow compared to measured flow under varying conditions during simulated cardiopulmonary bypass.

    LENUS (Irish Health Repository)

    Hargrove, M

    2008-07-01

    Errors in blood flow delivery due to shunting have been reported to reduce flow by, potentially, up to 40-83% during cardiopulmonary bypass. The standard roller-pump measures revolutions per minute and a calibration factor for different tubing sizes calculates and displays flow accordingly. We compared displayed roller-pump flow with ultrasonically measured flow to ascertain if measured flow correlated with the heart-lung pump flow reading. Comparison of flows was measured under varying conditions of pump run duration, temperature, viscosity, varying arterial\\/venous loops, occlusiveness, outlet pressure, use of silicone or polyvinyl chloride (PVC) in the roller race, different tubing diameters, and use of a venous vacuum-drainage device.

  6. Evaluation of lumbar tap test combined with mean cerebral blood flow measurement and electroencephalographic topography on idiopathic normal pressure hydrocephalus patients

    International Nuclear Information System (INIS)

    Takeuchi, Totaro; Iwasaki, Mitsuyoshi; Shirata, Kanji

    2004-01-01

    The purpose of this study was to improve the diagnostic precision of the lumbar tap test (LTT). Thirty one patients (mean age, 65.4 years; male to female ratio, 12: 19) suspected of having idiopathic normal pressure hydrocephalus (INPH) were used in the study. They underwent LTT (20-30 ml of cerebrospinal fluid was drained through a puncture with a 18 G needle; evaluation within 3 days after LTT). Based on changes in symptoms after LTT, includin