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Sample records for blood perfusion measurements

  1. Measurement of blood perfusion using photoacoustic, ultrasound, and strain imaging

    Science.gov (United States)

    Mallidi, Srivalleesha; Karpiouk, Andrei B.; Aglyamov, Salavat R.; Sethuraman, Shriram; Emelianov, Stanislav Y.

    2007-02-01

    In many clinical and research applications including cancer diagnosis, tumor response to therapy, reconstructive surgery, monitoring of transplanted tissues and organs, and quantitative evaluation of angiogenesis, sequential and quantitative assessment of microcirculation in tissue is required. In this paper we present an imaging technique capable of spatial and temporal measurements of blood perfusion through microcirculation. To demonstrate the developed imaging technique, studies were conducted using phantoms with modeled small blood vessels of various diameters positioned at different depths. A change in the magnitude of the photoacoustic signal was observed during vessel constriction and subsequent displacement of optically absorbing liquid present in the vessels. The results of the study suggest that photoacoustic, ultrasound and strain imaging could be used to sequentially monitor and qualitatively assess blood perfusion through microcirculation.

  2. Retinal hemodynamic oxygen reactivity assessed by perfusion velocity, blood oximetry and vessel diameter measurements

    DEFF Research Database (Denmark)

    Klefter, Oliver Niels; Lauritsen, Anne Øberg; Larsen, Michael

    2015-01-01

    PURPOSE: To test the oxygen reactivity of a fundus photographic method of measuring macular perfusion velocity and to integrate macular perfusion velocities with measurements of retinal vessel diameters and blood oxygen saturation. METHODS: Sixteen eyes in 16 healthy volunteers were studied at two...... (ICC) and limits of agreement. RESULTS: Fifteen minutes of hyperoxia was accompanied by mean reductions in arterial and venous perfusion velocities of 14% and 16%, respectively (p = 0.0080; p = 0.0019), constriction of major arteries and veins by 5.5% and 8.2%, respectively (p ...). For perfusion velocities, short-term ICCs were 0.79-0.82 and long-term ICCs were 0.06-0.11. Intersession increases in blood glucose were associated with reductions in perfusion velocities (arterial p = 0.0067; venous p = 0.018). CONCLUSION: Oxygen reactivity testing supported that motion-contrast velocimetry...

  3. [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%).

  4. 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

  5. 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

  6. 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...

  7. 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.

  8. Measuring myocardial perfusion

    DEFF Research Database (Denmark)

    Qayyum, A A; Kastrup, J

    2015-01-01

    Recently, focus has changed from anatomical assessment of coronary arteries towards functional testing to evaluate the effect of stenosis on the myocardium before intervention. Besides positron-emission tomography (PET), cardiac MRI (CMR), and cardiac CT are able to measure myocardial perfusion......-known and is used in routine clinical practice. However, PET uses radioactive tracers and has a lower spatial resolution compared to CMR and CT. CMR and CT are emerging techniques in the field of myocardial perfusion imaging. CMR uses magnetic resonance to obtain images, whereas CT uses x-rays during first....... Myocardial perfusion abnormalities are the first sign of the ischaemic cascade in the development of coronary artery disease (CAD). PET is considered the non-invasive clinical reference standard for absolute quantification of myocardial perfusion. The diagnostic and prognostic value of PET is well...

  9. Radiological contrast media and pancreatic blood perfusion in anesthetized rats.

    Science.gov (United States)

    Linder, G; Carlsson, P O; Källskog, Ö; Hansell, P; Jansson, L; Riesenfeld Källskog, V

    2007-12-01

    Radiological contrast media (CM) have been suggested to be able to impair pancreatic microcirculation. To evaluate the effects of an iso-osmolar (iodixanol, 290 mOsm/kg H2O) and a low-osmolar (iopromide, 660 mOsm/kg H2O) CM on total pancreatic and islet blood perfusion. Thiobutabarbital-anesthetized rats were injected with iodine equivalent doses (600 mg I/kg body weight) of iodixanol or iopromide. Saline or low-osmolar mannitol (660 mOsm/kg H2O) solutions served as control substances. Blood perfusion measurements were then carried out with a microsphere technique. Iso-osmolar iodixanol had no effects on blood perfusion. Low-osmolar iopromide increased total pancreatic blood perfusion, whereas islet blood perfusion was unchanged. No differences were seen when mannitol solutions were given. Neither an iso-osmolar nor a low-osmolar CM affected pancreatic islet blood perfusion, whereas the low-osmolar CM increased total pancreatic blood perfusion. The absence of hemodynamic effect of low-osmolar mannitol suggests that the hyperosmolality per se of iopromide versus iodixanol does not induce the hemodynamic effect. The consequences of the effect of iopromide for pancreatic function remain to be established.

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

    Science.gov (United States)

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

    2018-02-01

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

  11. Skin Blood Perfusion and Oxygenation Colour Affect Perceived Human Health

    Science.gov (United States)

    Stephen, Ian D.; Coetzee, Vinet; Law Smith, Miriam; Perrett, David I.

    2009-01-01

    Skin blood perfusion and oxygenation depends upon cardiovascular, hormonal and circulatory health in humans and provides socio-sexual signals of underlying physiology, dominance and reproductive status in some primates. We allowed participants to manipulate colour calibrated facial photographs along empirically-measured oxygenated and deoxygenated blood colour axes both separately and simultaneously, to optimise healthy appearance. Participants increased skin blood colour, particularly oxygenated, above basal levels to optimise healthy appearance. We show, therefore, that skin blood perfusion and oxygenation influence perceived health in a way that may be important to mate choice. PMID:19337378

  12. Measurement of brain perfusion, blood volume, and blood-brain barrier permeability, using dynamic contrast-enhanced T(1)-weighted MRI at 3 tesla.

    Science.gov (United States)

    Larsson, Henrik B W; Courivaud, Frédéric; Rostrup, Egill; Hansen, Adam E

    2009-11-01

    Assessment of vascular properties is essential to diagnosis and follow-up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood-brain permeability from dynamic T(1)-weighted imaging of a bolus of a paramagnetic contrast agent passing through the brain. The methods are applied in patients with brain tumors and in healthy subjects. Perfusion was estimated by model-free deconvolution using Tikhonov's method (gray matter/white matter/tumor: 72 +/- 16/30 +/- 8/56 +/- 45 mL/100 g/min); blood volume (6 +/- 2/4 +/- 1/7 +/- 6 mL/100 g) and permeability (0.9 +/- 0.4/0.8 +/- 0.3/3 +/- 5 mL/100 g/min) were estimated by using Patlak's method and a two-compartment model. A corroboration of these results was achieved by using model simulation. In addition, it was possible to generate maps on a pixel-by-pixel basis of cerebral perfusion, cerebral blood volume, and blood-brain barrier permeability. (c) 2009 Wiley-Liss, Inc.

  13. Measurement of brain perfusion, blood volume, and blood-brain barrier permeability, using dynamic contrast-enhanced T(1)-weighted MRI at 3 tesla

    DEFF Research Database (Denmark)

    Larsson, Henrik B W; Courivaud, Frédéric; Rostrup, Egill

    2009-01-01

    /min); blood volume (6 +/- 2/4 +/- 1/7 +/- 6 mL/100 g) and permeability (0.9 +/- 0.4/0.8 +/- 0.3/3 +/- 5 mL/100 g/min) were estimated by using Patlak's method and a two-compartment model. A corroboration of these results was achieved by using model simulation. In addition, it was possible to generate maps...... imaging of a bolus of a paramagnetic contrast agent passing through the brain. The methods are applied in patients with brain tumors and in healthy subjects. Perfusion was estimated by model-free deconvolution using Tikhonov's method (gray matter/white matter/tumor: 72 +/- 16/30 +/- 8/56 +/- 45 mL/100 g...

  14. PulseCam: high-resolution blood perfusion imaging using a camera and a pulse oximeter.

    Science.gov (United States)

    Kumar, Mayank; Suliburk, James; Veeraraghavan, Ashok; Sabharwal, Ashutosh

    2016-08-01

    Measuring blood perfusion is important in medical care as an indicator of injury and disease. However, currently available devices to measure blood perfusion like laser Doppler flowmetry are bulky, expensive, and cumbersome to use. An alternative low-cost and portable camera-based blood perfusion measurement system has recently been proposed, but such camera-only system produces noisy low-resolution blood perfusion maps. In this paper, we propose a new multi-sensor modality, named PulseCam, for measuring blood perfusion by combining a traditional pulse oximeter with a video camera in a unique way to provide low noise and high-resolution blood perfusion maps. Our proposed multi-sensor modality improves per pixel signal to noise ratio of measured perfusion map by up to 3 dB and improves the spatial resolution by 2 - 3 times compared to best known camera-only methods. Blood perfusion measured in the palm using our PulseCam setup during a post-occlusive reactive hyperemia (PORH) test replicates standard PORH response curve measured using laser Doppler flowmetry device but with much lower cost and a portable setup making it suitable for further development as a clinical device.

  15. Perfusion measurement in acute pancreatitis using dynamic perfusion MDCT.

    Science.gov (United States)

    Bize, Pierre E; Platon, Alexandra; Becker, Christoph D; Poletti, Pierre-Alexandre

    2006-01-01

    Our objective was to determine whether MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis in the initial phase of the disease. One hundred six patients with abdominal pain were prospectively enrolled in this study. Patients were separated into two groups: P1 (severe) and P2 (mild) acute pancreatitis. Mean perfusion value was 24.8 mL/100 mL/min in the P1 group and 50.5 mL/100 mL/min in the P2 group (p = 0.0016, significant). Our preliminary data suggest that pancreatic perfusion measurement using MDCT with perfusion imaging could help in assessing the severity of acute pancreatitis.

  16. Heat-washout measurements compared to distal blood pressure and perfusion in orthopaedic patients with foot ulcers

    DEFF Research Database (Denmark)

    Midttun, M; Azad, B B S; Broholm, R

    2015-01-01

    was poor (P = 0·333 and 0·685 for right and left 1. Toe, respectively) probably because not all measurements were performed under optimal conditions with maximally dilated arterioles and warm hands and feet. The patients already have maximally dilated arterioles to extract the maximal amount of oxygen from....... There was no statistical difference in the healthy controls, consistent with previous findings. These results may indicate that the heat-washout method can be used as an alternative to strain gauge blood pressure in the evaluation of peripheral artery disease and wound healing potentials. Furthermore, the heat...

  17. Skin Blood Perfusion and Cellular Response to Insertion of Insulin Pen Needles With Different Diameters

    DEFF Research Database (Denmark)

    Præstmark, Kezia Ann; Stallknecht, Bente Merete; Bo Jensen, Casper

    2014-01-01

    skin blood perfusion response around needle insertion sites. Three common sized pen needles of 28G, 30G, and 32G as well as hooked 32G needles, were inserted into the neck skin of pigs and then removed. Laser Speckle Contrast Analysis was used to measure skin blood perfusion for 20 minutes after...... blood perfusion recording and grouped according to needle type, skin blood perfusion response relates to needle diameter. The response was significantly higher after insertions with 28G and hooked 32G needles than with 30G (P ..., but there was a trend of an increased response with increasing needle diameter. Skin blood perfusion response to pen needle insertions rank according to needle diameter, and the tissue response caused by hooked 32G needles corresponds to that of 28G needles. The relation between needle diameter and trauma when...

  18. Early modifications of hepatic perfusion measured by functional CT in a rat model of hepatocellular carcinoma using a blood pool contrast agent

    International Nuclear Information System (INIS)

    Fournier, Laure S.; Cuenod, Charles Andre; Bazelaire, Cedric de; Siauve, Nathalie; Frija, Guy; Clement, Olivier; Rosty, Christophe; Tran, Phuong Lan

    2004-01-01

    Macromolecular contrast-enhanced functional CT was performed to characterize early perfusion changes in hepatocellular carcinoma (HCC). Fourteen rats with chemically induced primary liver tumors ranging pathologically from hyperplasia to HCC and 15 control rats were investigated. Two dynamic CT scans using an experimental macromolecular contrast agent were performed on a single slice 11 and 18 weeks after tumor induction followed by pathological examination. A deconvolution mathematical model was applied, yielding the hepatic perfusion index (HPI), mean transit time (MTT), liver distribution volume (LDV) and arterial, portal and total blood flows (FA, FP, FT). Analysis was performed on one slice per rat, containing overall two hyperplasia, six dysplasia and 15 HCC. On the first scans, HCC at an early pathological stage had a low FP (-30%, P=0.002) but a normal arterial-portal balance. On the scan contemporary to pathology, HCC perfusion parameters showed an inversion of the arterial-portal balance (HPI +212%, P<0.0001), with a high FA (+56%, P=0.002) and a low FP (-69%, P<0.0001). Sensitivity and specificity of detection of HCC by perfusion CT were high (87 and 80%) on late scans; but also on the earlier scans (86 and 65%), even though only one (7%) was visible to the eye. Perfusion-CT allowed early detection of HCC. This technique could contribute in the detection and characterization of liver lesions in clinical studies. (orig.)

  19. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  20. Xeno- and auto-perfusion of rabbit kidney. Machine perfusion with blood at 37 degrees C

    DEFF Research Database (Denmark)

    Jørgensen, K A; Kemp, E; Barfort, P

    1985-01-01

    Five rabbit kidneys were perfused with human blood and another five with their own blood in a re-circulating oxygenated system at 37 degrees C. The flow decreased to 2 ml/min. within 30 min. in all xenoperfusions, while none of the autoperfused had decreased to this level by 60 min. Endothelial...

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

    Victims of severe accidental hypothermia are prone to fluid extravasation but rarely develop lung edema. We hypothesize that combined hypothermia-induced increase in pulmonary vascular resistance (PVR) and a concomitant fall in cardiac output protect the lungs against edema development. Our aim was to explore in hypothermic-isolated blood-perfused rat lungs whether perfusion at constant pressure influences fluid filtration differently from perfusion at constant flow. Isolated blood-perfused rat lungs were hanging freely in a weight transducer for measuring weight changes (ΔW). Fluid filtration coefficient (Kfc), was determined by transiently elevating left atrial pressure (Pla) by 5.8 mmHg two times each during normothermia (37°C) and during hypothermia (15°C). The lung preparations were randomized to two groups. One group was perfused with constant flow (Constant flow group) and the other group with constant pulmonary artery pressure (Constant PPA group). Microvascular pressure (Pmv) was determined before and during elevation of Pla (ΔPmv) by means of the double occlusion technique. Kfc was calculated with the formula Kfc = ΔW/ΔPmv/min. All Kfc values were normalized to predicted lung weight (P LW ), which was based on body weight (BW) according to the formula: P LW  = 0.0053 BW - 0.48 and presented as Kfc PLW in mg/min/mmHg/g. At cessation, bronchoalveolar lavage (BAL) fluid/perfusate protein concentration (B/P) ratio was determined photometrically. Data were analyzed with parametric or non-parametric tests as appropriate. p  < 0.05 considered as significant. Perfusate flow remained constant in the Constant flow group, but was more than halved during hypothermia in the Constant PPA group concomitant with a more fold increase in PVR. In the Constant flow group, Kfc PLW and B/P ratio increased significantly by more than 10-fold during hypothermia concerted by visible signs of edema in the trachea. Hemoglobin and hematocrit increased within

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

    Science.gov (United States)

    Xie, Haiwei; Zhang, Yan

    2018-03-01

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

  4. Doppler Monte Carlo simulations of light scattering in tissue to support laser-Doppler perfusion measurements

    NARCIS (Netherlands)

    de Mul, F.F.M.; Steenbergen, Wiendelt; Greve, Jan

    1999-01-01

    Doppler Monte Carlo (DMC) simulations of the transport of light through turbid media, e.g., tissue, can be used to predict or to interpret measurements of the blood perfusion of tissue by laser‐Doppler perfusion flowmetry. We describe the physical and mathematical background of Doppler Monte Carlo

  5. Shape matters: the effect of red blood cell shape on perfusion of an artificial microvascular network.

    Science.gov (United States)

    Piety, Nathaniel Z; Reinhart, Walter H; Pourreau, Patrick H; Abidi, Rajaa; Shevkoplyas, Sergey S

    2016-04-01

    The shape of human red blood cells (RBCs) deteriorates progressively throughout hypothermic storage, with echinocytosis being the most prevalent pathway of this morphologic lesion. As a result, each unit of stored blood contains a heterogeneous mixture of cells in various stages of echinocytosis and normal discocytes. Here we studied how the change in shape of RBCs following along the path of the echinocytic transformation affects perfusion of an artificial microvascular network (AMVN). Blood samples were obtained from healthy consenting volunteers. RBCs were leukoreduced, resuspended in saline, and treated with various concentrations of sodium salicylate to induce shape changes approximating the stages of echinocytosis experienced by RBCs during hypothermic storage (e.g., discocyte, echinocyte I, echinocyte II, echinocyte III, spheroechinocyte, and spherocyte). The AMVN perfusion rate was measured for 40% hematocrit suspensions of RBCs with different shapes. The AMVN perfusion rates for RBCs with discocyte and echinocyte I shapes were similar, but there was a significant decline in the AMVN perfusion rate between RBCs with shapes approximating each subsequent stage of echinocytosis. The difference in AMVN perfusion between discocytes and spherocytes (the last stage of the echinocytic transformation) was 34%. The change in shape of RBCs from normal discocytes progressively through various stages of echinocytosis to spherocytes produced a substantial decline in the ability of these cells to perfuse an AMVN. Echinocytosis induced by hypothermic storage could therefore be responsible for a similarly substantial impairment of deformability previously observed for stored RBCs. © 2015 AABB.

  6. Xeno- and auto-perfusion of rabbit kidney. Machine perfusion with blood at 37 degrees C

    DEFF Research Database (Denmark)

    Jørgensen, K A; Kemp, E; Barfort, P

    1985-01-01

    damage, exudation, and IgG deposits along the basement membrane of the glomerular capillaries were the discriminative features of the xenoperfusion. In these experiments, we were unable to demonstrate any major role of platelets in the process leading to decreased blood flow.......Five rabbit kidneys were perfused with human blood and another five with their own blood in a re-circulating oxygenated system at 37 degrees C. The flow decreased to 2 ml/min. within 30 min. in all xenoperfusions, while none of the autoperfused had decreased to this level by 60 min. Endothelial...

  7. Cryotherapy-Induced Persistent Vasoconstriction After Cutaneous Cooling: Hysteresis Between Skin Temperature and Blood Perfusion

    Science.gov (United States)

    Khoshnevis, Sepideh; Craik, Natalie K.; Matthew Brothers, R.; Diller, Kenneth R.

    2016-01-01

    The goal of this study was to investigate the persistence of cold-induced vasoconstriction following cessation of active skin-surface cooling. This study demonstrates a hysteresis effect that develops between skin temperature and blood perfusion during the cooling and subsequent rewarming period. An Arctic Ice cryotherapy unit (CTU) was applied to the knee region of six healthy subjects for 60 min of active cooling followed by 120 min of passive rewarming. Multiple laser Doppler flowmetry perfusion probes were used to measure skin blood flow (expressed as cutaneous vascular conductance (CVC)). Skin surface cooling produced a significant reduction in CVC (P cryotherapy. PMID:26632263

  8. A novel microthermal probe for the measurement of perfusion

    Science.gov (United States)

    Yi, Ming; Kausik, Aditya; Podhajsky, Ronald J.; Mahajan, Roop L.

    2009-02-01

    Using micro-fabrication techniques a micro thermal probe has been developed in our laboratory to measure the thermal conductivity of biological tissues. This paper presents our latest experimental results which demonstrate the usefulness of the micro thermal probe in mapping the complicated perfusion field inside biological tissues. A perfused pig liver model has been constructed to simulate in vivo conditions. The portal vein and hepatic artery of a porcine liver were intubated and connected to a perfusion circuit. Saline water was perfused through the liver driven by a peristaltic pump. By varying the pumping rate of the perfused model, we measured the effective thermal conductivity at different perfusion rates in different locations. The results show that the effective thermal conductivity varies with the square root of the perfusion rate. Also, by rotating the micro probes, we observed a strong directional dependence of the effective thermal conductivity, revealing that perfusion is not a scalar but a vector field.

  9. The relationship between red blood cell deformability metrics and perfusion of an artificial microvascular network.

    Science.gov (United States)

    Sosa, Jose M; Nielsen, Nathan D; Vignes, Seth M; Chen, Tanya G; Shevkoplyas, Sergey S

    2014-01-01

    The ability of red blood cells (RBC) to undergo a wide range of deformations while traversing the microvasculature is crucial for adequate perfusion. Interpretation of RBC deformability measurements performed in vitro in the context of microvascular perfusion has been notoriously difficult. This study compares the measurements of RBC deformability performed using micropore filtration and ektacytometry with the RBC ability to perfuse an artificial microvascular network (AMVN). Human RBCs were collected from healthy consenting volunteers, leukoreduced, washed and exposed to graded concentrations (0-0.08%) of glutaraldehyde (a non-specific protein cross-linker) and diamide (a spectrin-specific protein cross-linker) to impair the deformability of RBCs. Samples comprising cells with two different levels of deformability were created by adding non-deformable RBCs (hardened by exposure to 0.08% glutaraldehyde) to the sample of normal healthy RBCs. Ektacytometry indicated a nearly linear decline in RBC deformability with increasing glutaraldehyde concentration. Micropore filtration showed a significant reduction only for concentrations of glutaraldehyde higher than 0.04%. Neither micropore filtration nor ektacytometry measurements could accurately predict the AMVN perfusion. Treatment with diamide reduced RBC deformability as indicated by ektacytometry, but had no significant effect on either micropore filtration or the AMVN perfusion. Both micropore filtration and ektacytometry showed a linear decline in effective RBC deformability with increasing fraction of non-deformable RBCs in the sample. The corresponding decline in the AMVN perfusion plateaued above 50%, reflecting the innate ability of blood flow in the microvasculature to bypass occluded capillaries. Our results suggest that in vitro measurements of RBC deformability performed using either micropore filtration or ektacytometry may not represent the ability of same RBCs to perfuse microvascular networks. Further

  10. Phthalate monoesters in perfusate from a dual placenta perfusion system, the placenta tissue and umbilical cord blood

    DEFF Research Database (Denmark)

    Mose, Tina; Mortensen, Gerda K; Hedegaard, Morten

    2006-01-01

    BP), and mono (2-ethyl-hexyl) phthalate (mEHP) were detected in both maternal and fetal perfusate, demonstrating a release of compounds from tissue or blood to perfusates. The distribution of compounds between perfusate, umbilical cord plasma, and tissue was in accordance with the physical-chemical properties...... of the compounds. Results from the present study of compounds residing in the tissue are essential before studying human transplacental transfer, storage, and metabolism of selected phthalate monoesters....

  11. Selective renal blood perfusion induces renal tubules injury in a porcine model.

    Science.gov (United States)

    Kalder, Johannes; Kokozidou, Maria; Keschenau, Paula; Tamm, Miriam; Greiner, Andreas; Koeppel, Thomas A; Tolba, Rene; Jacobs, Michael J

    2016-03-01

    Extracorporeal circulation is routinely used in thoracoabdominal aortic aneurysm repair to preserve blood perfusion. Despite this protective measure, acute and chronic kidney disorders can develop. Therefore, the aim of this study was to establish a new large-animal model to assess the efficacy of selective renal perfusion (SRP) with extracorporeal circulation in a setting of thoracoabdominal aortic aneurysm repair. Eighteen pigs underwent a thoracolaparotomy, during with the aorta and renal arteries were exposed. The animals were divided into three cohorts of six pigs each: cohort I--control; cohort II--thoracic aortic clamping with distal aortic perfusion (DAP) using a roller pump; and cohort III--thoracic aortic clamping with DAP plus SRP. Kidney metabolism, kidney injury, and red blood cell damage were measured by oxygen extraction ratio (O2ER), neutrophil gelatinase-associated lipocalin, a marker for acute kidney damage, and serum free hemoglobin. With normal mean arterial blood pressures, flow rates in the renal arteries during perfusion decreased to 75% (group II) with DAP and to 50% (group III) with SRP compared with the control animals (group I; P = .0279 for I vs II; P = .0002 for I vs III). Microcirculation, measured by microspheres, did not differ significantly among the groups. In contrast, O2ER (P = .0021 for I vs III) and neutrophil gelatinase-associated lipocalin (P = .0083 for I vs III) levels were significantly increased in group III, whereas free hemoglobin was increased in groups II and III (P = .0406 for I vs II; P = .0018 for I vs III). SRP with a roller pump induces kidney tubule injury. Thus, distal aortic and SRP in our model does not provide adequate kidney protection. Furthermore, the perfusion system provokes red blood cell damage with increased free hemoglobin. Hence, the SRP perfusion technique should be revised and tested. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  12. Motion Tracking System for Robust Non-Contact Blood Perfusion Sensor

    Directory of Open Access Journals (Sweden)

    Masaaki Hashimoto

    2018-01-01

    Full Text Available We propose a motion-robust laser Doppler flowmetry (LDF system that can be used as a non-contact blood perfusion sensor for medical diagnosis. Endoscopic LDF systems are typically limited in their usefulness in clinical contexts by the need for the natural organs to be immobilized, as serious motion artifacts due to the axial surface displacement can interfere with blood perfusion measurements. In our system, the focusing lens moves to track the motion of the target using a low-frequency reference signal in the optical data, enabling the suppression of these motion artifacts in the axial direction. This paper reports feasibility tests on a prototype of this system using a microfluidic phantom as a measurement target moving in the direction of the optical axis. The frequency spectra detected and the perfusion values calculated from those spectra show that the motion tracking system is capable of suppressing motion artifacts in perfusion readings. We compared the prototype LDF system’s measurements with and without motion feedback, and found that motion tracking improves the fidelity of the perfusion signal by as much as 87%.

  13. Cerebral blood flow is an earlier indicator of perfusion abnormalities than cerebral blood volume in Alzheimer's disease

    OpenAIRE

    Lacalle-Aurioles, María; Mateos-Pérez, José M; Guzmán-De-Villoria, Juan A; Olazarán, Javier; Cruz-Orduña, Isabel; Alemán-Gómez, Yasser; Martino, María-Elena; Desco, Manuel

    2014-01-01

    The purpose of this study was to elucidate whether cerebral blood flow (CBF) can better characterize perfusion abnormalities in predementia stages of Alzheimer's disease (AD) than cerebral blood volume (CBV) and whether cortical atrophy is more associated with decreased CBV or with decreased CBF. We compared measurements of CBV, CBF, and mean cortical thickness obtained from magnetic resonance images in a group of healthy controls, patients with mild cognitive impairment (MCI) who converted t...

  14. CT perfusion of the liver during selective hepatic arteriography. Pure arterial blood perfusion of liver tumor and parenchyma

    International Nuclear Information System (INIS)

    Komemushi, Atsushi; Tanigawa, Noboru; Kojima, Hiroyuki; Kariya, Shuji; Sawada, Satoshi

    2003-01-01

    The purpose of this study was to quantify pure arterial blood perfusion of liver tumor and parenchyma by using CT perfusion during selective hepatic arteriography. A total of 44 patients underwent liver CT perfusion study by injection of contrast medium via the hepatic artery. CT-perfusion parameters including arterial blood flow, arterial blood volume, and arterial mean transit time in the liver parenchyma and liver tumor were calculated using the deconvolution method. The CT-perfusion parameters and vascularity of the tumor were compared. A complete analysis could be performed in 36 of the 44 patients. For liver tumor and liver parenchyma, respectively, arterial blood flow was 184.6±132.7 and 41.0±27.0 ml/min/100 g, arterial blood volume was 19.4±14.6 and 4.8±4.2 ml/100 g, and arterial mean transit time was 8.9±4.2 and 10.2±5.3 sec. Arterial blood flow and arterial blood volume correlated significantly with the vascularity of the tumor; however no correlation was detected between arterial mean transit time and the vascularity of the tumor. This technique could be used to quantify pure hepatic arterial blood perfusion. (author)

  15. Investigation of source-detector separation optimization for an implantable perfusion and oxygenation sensor for liver blood vessels

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Justin S [ORNL; Akl, Tony [Texas A& M University; Cote, Gerard L. [Texas A& M University; Wilson, Mark A. [University of Pittsburgh School of Medicine, Pittsburgh PA; Ericson, Milton Nance [ORNL

    2011-01-01

    An implanted system is being developed to monitor transplanted liver health during the critical 7-10 day period posttransplantation. The unit will monitor organ perfusion and oxygen consumption using optically-based probes placed on both the inflow and outflow blood vessels, and on the liver parenchymal surface. Sensing probes are based on a 3- wavelength LED source and a photodiode detector. Sample diffuse reflectance is measured at 735, 805, and 940 nm. To ascertain optimal source-to-photodetector spacing for perfusion measurement in blood vessels, an ex vivo study was conducted. In this work, a dye mixture simulating 80% blood oxygen saturation was developed and perfused through excised porcine arteries while collecting data for various preset probe source-to-photodetector spacings. The results from this study demonstrate a decrease in the optical signal with decreasing LED drive current and a reduction in perfusion index signal with increasing probe spacing. They also reveal a 2- to 4-mm optimal range for blood vessel perfusion probe source-to-photodetector spacing that allows for sufficient perfusion signal modulation depth with maximized signal to noise ratio (SNR). These findings are currently being applied to guide electronic configuration and probe placement for in vivo liver perfusion porcine model studies.

  16. Quantitative measurement of renal perfusion following transplant surgery

    International Nuclear Information System (INIS)

    Lear, J.L.; Raff, U.; Jain, R.; Horgan, J.G.

    1988-01-01

    We developed an easily implemented clinical procedure for quantitative perfusion measurements in transplanted kidneys using intravenously administered [/sup 99m/Tc]DTPA and the tracer fractionation technique. F = Ak(T)/0 integral of T [Aa(t)/Va] dt, where F = renal blood flow, Ak(T) = DTPA activity in kidney at time = T, Va = ultrasonographically measured femoral artery segment volume, T = time postinjection of F determination, and Aa(t) = time course of DTPA activity in femoral artery segment. The technique was applied to a group of 80 studies in 35 patients in whom an independent clinical determination of transplant function was available. Blood flow (units of ml/min) measured 439 +/- 83 in normally functioning transplants, 248 +/- 63 in transplants with acute tubular necrosis, 128 +/- 62 in transplants with rejection, and 284 +/- 97 in transplants with cyclosporine toxicity. These preliminary results indicate potential usefulness of this method in the evaluation of renal function following transplant surgery

  17. Blood temperature and perfusion to exercising and non-exercising human limbs.

    Science.gov (United States)

    González-Alonso, José; Calbet, José A L; Boushel, Robert; Helge, Jørn W; Søndergaard, Hans; Munch-Andersen, Thor; van Hall, Gerrit; Mortensen, Stefan P; Secher, Niels H

    2015-10-01

    What is the central question of this study? Temperature-sensitive mechanisms are thought to contribute to blood-flow regulation, but the relationship between exercising and non-exercising limb perfusion and blood temperature is not established. What is the main finding and its importance? The close coupling among perfusion, blood temperature and aerobic metabolism in exercising and non-exercising extremities across different exercise modalities and activity levels and the tight association between limb vasodilatation and increases in plasma ATP suggest that both temperature- and metabolism-sensitive mechanisms are important for the control of human limb perfusion, possibly by activating ATP release from the erythrocytes. Temperature-sensitive mechanisms may contribute to blood-flow regulation, but the influence of temperature on perfusion to exercising and non-exercising human limbs is not established. Blood temperature (TB ), blood flow and oxygen uptake (V̇O2) in the legs and arms were measured in 16 healthy humans during 90 min of leg and arm exercise and during exhaustive incremental leg or arm exercise. During prolonged exercise, leg blood flow (LBF) was fourfold higher than arm blood flow (ABF) in association with higher TB and limb V̇O2. Leg and arm vascular conductance during exercise compared with rest was related closely to TB (r(2) = 0.91; P incremental leg exercise, LBF increased in association with elevations in TB and limb V̇O2, whereas ABF, arm TB and V̇O2 remained largely unchanged. During incremental arm exercise, both ABF and LBF increased in relationship to similar increases in V̇O2. In 12 trained males, increases in femoral TB and LBF during incremental leg exercise were mirrored by similar pulmonary artery TB and cardiac output dynamics, suggesting that processes in active limbs dominate central temperature and perfusion responses. The present data reveal a close coupling among perfusion, TB and aerobic metabolism in exercising and non

  18. Dynamic CT perfusion measurement in a cardiac phantom.

    Science.gov (United States)

    Ziemer, Benjamin P; Hubbard, Logan; Lipinski, Jerry; Molloi, Sabee

    2015-10-01

    Widespread clinical implementation of dynamic CT myocardial perfusion has been hampered by its limited accuracy and high radiation dose. The purpose of this study was to evaluate the accuracy and radiation dose reduction of a dynamic CT myocardial perfusion technique based on first pass analysis (FPA). To test the FPA technique, a pulsatile pump was used to generate known perfusion rates in a range of 0.96-2.49 mL/min/g. All the known perfusion rates were determined using an ultrasonic flow probe and the known mass of the perfusion volume. FPA and maximum slope model (MSM) perfusion rates were measured using volume scans acquired from a 320-slice CT scanner, and then compared to the known perfusion rates. The measured perfusion using FPA (P(FPA)), with two volume scans, and the maximum slope model (P(MSM)) were related to known perfusion (P(K)) by P(FPA) = 0.91P(K) + 0.06 (r = 0.98) and P(MSM) = 0.25P(K) - 0.02 (r = 0.96), respectively. The standard error of estimate for the FPA technique, using two volume scans, and the MSM was 0.14 and 0.30 mL/min/g, respectively. The estimated radiation dose required for the FPA technique with two volume scans and the MSM was 2.6 and 11.7-17.5 mSv, respectively. Therefore, the FPA technique can yield accurate perfusion measurements using as few as two volume scans, corresponding to approximately a factor of four reductions in radiation dose as compared with the currently available MSM. In conclusion, the results of the study indicate that the FPA technique can make accurate dynamic CT perfusion measurements over a range of clinically relevant perfusion rates, while substantially reducing radiation dose, as compared to currently available dynamic CT perfusion techniques.

  19. 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

  20. Critical cerebral perfusion pressure at high intracranial pressure measured by induced cerebrovascular and intracranial pressure reactivity.

    Science.gov (United States)

    Bragin, Denis E; Statom, Gloria L; Yonas, Howard; Dai, Xingping; Nemoto, Edwin M

    2014-12-01

    The lower limit of cerebral blood flow autoregulation is the critical cerebral perfusion pressure at which cerebral blood flow begins to fall. It is important that cerebral perfusion pressure be maintained above this level to ensure adequate cerebral blood flow, especially in patients with high intracranial pressure. However, the critical cerebral perfusion pressure of 50 mm Hg, obtained by decreasing mean arterial pressure, differs from the value of 30 mm Hg, obtained by increasing intracranial pressure, which we previously showed was due to microvascular shunt flow maintenance of a falsely high cerebral blood flow. The present study shows that the critical cerebral perfusion pressure, measured by increasing intracranial pressure to decrease cerebral perfusion pressure, is inaccurate but accurately determined by dopamine-induced dynamic intracranial pressure reactivity and cerebrovascular reactivity. Cerebral perfusion pressure was decreased either by increasing intracranial pressure or decreasing mean arterial pressure and the critical cerebral perfusion pressure by both methods compared. Cortical Doppler flux, intracranial pressure, and mean arterial pressure were monitored throughout the study. At each cerebral perfusion pressure, we measured microvascular RBC flow velocity, blood-brain barrier integrity (transcapillary dye extravasation), and tissue oxygenation (reduced nicotinamide adenine dinucleotide) in the cerebral cortex of rats using in vivo two-photon laser scanning microscopy. University laboratory. Male Sprague-Dawley rats. At each cerebral perfusion pressure, dopamine-induced arterial pressure transients (~10 mm Hg, ~45 s duration) were used to measure induced intracranial pressure reactivity (Δ intracranial pressure/Δ mean arterial pressure) and induced cerebrovascular reactivity (Δ cerebral blood flow/Δ mean arterial pressure). At a normal cerebral perfusion pressure of 70 mm Hg, 10 mm Hg mean arterial pressure pulses had no effect on

  1. Blood temperature and perfusion to exercising and non‐exercising human limbs

    Science.gov (United States)

    Calbet, José A. L.; Boushel, Robert; Helge, Jørn W.; Søndergaard, Hans; Munch‐Andersen, Thor; van Hall, Gerrit; Mortensen, Stefan P.; Secher, Niels H.

    2015-01-01

    New Findings What is the central question of this study? Temperature‐sensitive mechanisms are thought to contribute to blood‐flow regulation, but the relationship between exercising and non‐exercising limb perfusion and blood temperature is not established. What is the main finding and its importance? The close coupling among perfusion, blood temperature and aerobic metabolism in exercising and non‐exercising extremities across different exercise modalities and activity levels and the tight association between limb vasodilatation and increases in plasma ATP suggest that both temperature‐ and metabolism‐sensitive mechanisms are important for the control of human limb perfusion, possibly by activating ATP release from the erythrocytes. Temperature‐sensitive mechanisms may contribute to blood‐flow regulation, but the influence of temperature on perfusion to exercising and non‐exercising human limbs is not established. Blood temperature (T B), blood flow and oxygen uptake (V˙O2) in the legs and arms were measured in 16 healthy humans during 90 min of leg and arm exercise and during exhaustive incremental leg or arm exercise. During prolonged exercise, leg blood flow (LBF) was fourfold higher than arm blood flow (ABF) in association with higher T B and limb V˙O2. Leg and arm vascular conductance during exercise compared with rest was related closely to T B (r 2 = 0.91; P incremental leg exercise, LBF increased in association with elevations in T B and limb V˙O2, whereas ABF, arm T B and V˙O2 remained largely unchanged. During incremental arm exercise, both ABF and LBF increased in relationship to similar increases in V˙O2. In 12 trained males, increases in femoral T B and LBF during incremental leg exercise were mirrored by similar pulmonary artery T B and cardiac output dynamics, suggesting that processes in active limbs dominate central temperature and perfusion responses. The present data reveal a close coupling among perfusion, T B and

  2. In situ measurements of magnetic nanoparticles after placenta perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Müller, Robert, E-mail: robert.mueller@ipht-jena.de [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany); Gläser, Marcus [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany); University of Applied Sciences, Jena (Germany); Göhner, Claudia; Seyfarth, Lydia; Schleussner, Ekkehard [Department of Obstetrics and Gynecology, Jena University Hospital (Germany); Hofmann, Andreas [HTS Systeme GmbH, Wallenfels (Germany); Fritzsche, Wolfgang [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany)

    2015-04-15

    Nanoparticles (NP) present promising tools for medical applications. However, the investigation of their spatial and temporal distribution is hampered by missing in-situ particle detection and quantification technologies. The placenta perfusion experiment represents an interesting model for the study of the particle distribution at a biological barrier. It allows the ex-vivo investigation of the permeability of the placenta for materials of interest. We introduce an approach based on a magnetic system for an in situ measurement of the concentration of magnetic NPs in such an experiment. A previously off-line utilized magnetic readout device (sensitivity of ≈10{sup −8} Am{sup 2}) was used for long term measurements of magnetic NP of 100–150 nm size range in a closed circuit of a placenta perfusion. It represents a semiquantitative approach. The behavior of particles in the placenta and in the measurement system was studied, as well as the influence of particle surface modifications. The results suggest a transfer of a low amount of particles from the maternal to the fetal blood circuit.

  3. In situ measurements of magnetic nanoparticles after placenta perfusion

    Science.gov (United States)

    Müller, Robert; Gläser, Marcus; Göhner, Claudia; Seyfarth, Lydia; Schleussner, Ekkehard; Hofmann, Andreas; Fritzsche, Wolfgang

    2015-04-01

    Nanoparticles (NP) present promising tools for medical applications. However, the investigation of their spatial and temporal distribution is hampered by missing in-situ particle detection and quantification technologies. The placenta perfusion experiment represents an interesting model for the study of the particle distribution at a biological barrier. It allows the ex-vivo investigation of the permeability of the placenta for materials of interest. We introduce an approach based on a magnetic system for an in situ measurement of the concentration of magnetic NPs in such an experiment. A previously off-line utilized magnetic readout device (sensitivity of ≈10-8 Am2) was used for long term measurements of magnetic NP of 100-150 nm size range in a closed circuit of a placenta perfusion. It represents a semiquantitative approach. The behavior of particles in the placenta and in the measurement system was studied, as well as the influence of particle surface modifications. The results suggest a transfer of a low amount of particles from the maternal to the fetal blood circuit.

  4. Slaughterhouse blood as a perfusate for studying myocardial function under ischemic conditions

    Directory of Open Access Journals (Sweden)

    Bendjelid K.

    2003-01-01

    Full Text Available Metabolic studies using the in vitro non-recirculating blood-perfused isolated heart model require large volumes of blood. The present study was designed to determine whether heterologous pig blood collected from a slaughterhouse can be used as perfusate for isolated pig hearts perfused under aerobic and constant reduced flow conditions. Eight isolated working pig hearts perfused for 90 min at a constant flow of 1.5 ml g-1 min-1 with non-recirculated blood diluted with Krebs-Henseleit bicarbonate buffer at a hematocrit of 23% were compared to eight hearts subjected to the same protocol but perfused only with Krebs-Henseleit bicarbonate buffer solution. Hearts were paced at 100 bpm and subjected to aerobic perfusion at 38ºC. Hearts were weighed before perfusion and at the end of the experiment and the results are reported as percent weight gain (mean ± SD. Comparisons between groups were performed by the Student t-test (P<0.05. After 90 min of perfusion with modified Krebs-Henseleit, perfused hearts presented a larger weight gain than blood-perfused hearts (39.34 ± 9.27 vs 23.13 ± 5.42%, P = 0.003. Left ventricular end-diastolic pressure was higher in the modified Krebs-Henseleit-perfused group than in the blood group (2.8 ± 0.4 vs 2.3 ± 0.3 mmHg, respectively, P = 0.01. We conclude that heterologous blood perfusion, by preserving a more physiological myocardial water content, is a better perfusion fluid than modified Krebs-Henseleit solution for quantitative studies of myocardial metabolism and heart function under ischemic conditions.

  5. Differentiation between diverticulitis and colorectal cancer: quantitative CT perfusion measurements versus morphologic criteria--initial experience.

    Science.gov (United States)

    Goh, Vicky; Halligan, Steve; Taylor, Stuart A; Burling, David; Bassett, Paul; Bartram, Clive I

    2007-02-01

    To determine whether computed tomographic (CT) perfusion measurements in prospectively recruited patients can be used to differentiate between diverticulitis and colorectal cancer and to compare this discrimination with that of standard morphologic criteria. After institutional review board approval and written informed consent were obtained, 60 patients (24 men, 36 women; mean age, 69 years; range, 33.5-90.4 years; 20 patients with cancer, 20 with diverticulitis, and 20 with inactive diverticular disease) underwent CT perfusion imaging at the level of the colonic abnormality, and perfusion parameters were calculated. Analysis of variance was used to investigate any differences in perfusion between the patient groups. Two independent observers also analyzed an abdominopelvic CT study obtained immediately after the CT perfusion study and noted standard morphologic criteria for differential diagnosis. The sensitivity and specificity of CT perfusion measurements for determining the diagnostic category were compared with morphologic criteria by means of multivariate analysis to identify the most discriminatory criteria. Mean blood volume, blood flow, transit time, and permeability were significantly different between patients with cancer and those with diverticulitis (P diagnostic category were blood volume, transit time, permeability, and presence of pericolonic nodes (P = .05, .02, .04, and .02, respectively). Blood volume and blood flow each had a sensitivity of 80% and had specificity of 70% and 75%, respectively, for cancer in comparison with standard morphologic criteria: less than 5 cm of bowel involvement (45% sensitivity, 95% specificity), presence of a mass (85% sensitivity, 90% specificity), pericolonic inflammation (75% sensitivity, 5% specificity), and pericolonic nodes (90% sensitivity, 45% specificity). CT perfusion measurements enable differentiation and better discrimination, in comparison with morphologic criteria, between cancer and diverticulitis

  6. Quantitative dual energy CT measurements in rabbit VX2 liver tumors: Comparison to perfusion CT measurements and histopathological findings

    International Nuclear Information System (INIS)

    Zhang, Long Jiang; Wu, Shengyong; Wang, Mei; Lu, Li; Chen, Bo; Jin, Lixin; Wang, Jiandong; Larson, Andrew C.; Lu, Guang Ming

    2012-01-01

    Purpose: To evaluate the correlation between quantitative dual energy CT and perfusion CT measurements in rabbit VX2 liver tumors. Materials and methods: This study was approved by the institutional animal care and use committee at our institution. Nine rabbits with VX2 liver tumors underwent contrast-enhanced dual energy CT and perfusion CT. CT attenuation for the tumors and normal liver parenchyma and tumor-to-liver ratio were obtained at the 140 kVp, 80 kVp, average weighted images and dual energy CT iodine maps. Quantitative parameters for the viable tumor and adjacent liver were measured with perfusion CT. The correlation between the enhancement values of the tumor in iodine maps and perfusion CT parameters of each tumor was analyzed. Radiation dose from dual energy CT and perfusion CT was measured. Results: Enhancement values for the tumor were higher than that for normal liver parenchyma at the hepatic arterial phase (P < 0.05). The highest tumor-to-liver ratio was obtained in hepatic arterial phase iodine map. Hepatic blood flow of the tumor was higher than that for adjacent liver (P < 0.05). Enhancement values of hepatic tumors in the iodine maps positively correlated with permeability of capillary vessel surface (r = 0.913, P < 0.001), hepatic blood flow (r = 0.512, P = 0.010), and hepatic blood volume (r = 0.464, P = 0.022) at the hepatic arterial phases. The effective radiation dose from perfusion CT was higher than that from DECT (P < 0.001). Conclusions: The enhancement values for viable tumor tissues measured in iodine maps were well correlated to perfusion CT measurements in rabbit VX2 liver tumors. Compared with perfusion CT, dual energy CT of the liver required a lower radiation dose.

  7. 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.

  8. Thermal tests for laser Doppler perfusion measurements in Raynaud's syndrome

    Science.gov (United States)

    Kacprzak, Michal; Skora, A.; Obidzinska, J.; Zbiec, A.; Maniewski, Roman; Staszkiewicz, W.

    2004-07-01

    The laser Doppler method offers a non-invasive, real time technique for monitoring of blood perfusion in microcirculation. In practical measurements the perfusion index is given only in relative values. Thus, accurate and reproducible results can be only obtained when using a well controlled stimulation test. The aim of this study was evaluation of the thermal stimulation test, which is frequently used to investigate microcirculation in patients with Raynaud's syndrome. Three types of thermal tests, in which air or water with temperature in range 5°C - 40°C were used. Ten normal volunteers and fifteen patients with clinical symptoms of the primary Raynaud's syndrome were enrolled in this study. To estimate skin microcirculation changes during the thermal test, the multichannel laser Doppler system and laser Doppler scanner were used. The obtained results were analyzed from the point of view of the efficiency of these methods and the thermal provocative tests in differentiation of normal subjects and patient with Raynaud's syndrome.

  9. Lung perfusion in hemorrhagic shock of rats. The effects of resuscitation with whole blood, saline or hes 6%

    International Nuclear Information System (INIS)

    Turhanoglu, S.; Kaya, S.; Kararmaz, A.; Turhanoglu, A.D.

    2001-01-01

    This study was undertaken to determine the effects of various resuscitation regimens on lung perfusion following resuscitation from hemorrhagic shock. Fourty male Sprague-Dawley rats (250-300 g) were used. The rats were divided randomly into four groups (n=10 for each) and were sedated with intramuscular ketamine (100 mg/kg). We measured blood pressure, rectal temperature and lung perfusion using radioscintigraphy with a technetium colloid indicator. The systolic blood pressure was decreased 75% by removing blood via v. jugularis in the first three groups and group 4 was accepted as the control group, and blood volume was not diminished. Then the first three groups were resuscitated with autologous blood containing 125 units heparine/ml in group 1, saline in group 2, and hydroxyethyl starch (HES) 6% in group 3. After the correction of hypovolemia, all animals were injected 100 Bg (0.1 cc) technetium 99m macroaggregated albumin ( 99m Tc MAA) via penil vein. After injection of 99m Tc MAA, 3 minutes fixed images were detected by a γ camera in posterior position at 15 minutes and 5 hours. 99m Tc MMA ''wash out'' rate in lung was determined quantitatively at 5 hours. Compared to a control group, lung perfusion was decreased significantly in groups resuscitated with saline, and HES 6% while perfusion was restored with autologous blood. We conclude that heparinized autologous blood saved lung capillary circulation in hemorrhagic shock in rats. (author)

  10. Lung perfusion in hemorrhagic shock of rats. The effects of resuscitation with whole blood, saline or hes 6%

    Energy Technology Data Exchange (ETDEWEB)

    Turhanoglu, S.; Kaya, S.; Kararmaz, A.; Turhanoglu, A.D. [Dicle Univ., Diyarbakir (Turkey). Medical School

    2001-12-01

    This study was undertaken to determine the effects of various resuscitation regimens on lung perfusion following resuscitation from hemorrhagic shock. Fourty male Sprague-Dawley rats (250-300 g) were used. The rats were divided randomly into four groups (n=10 for each) and were sedated with intramuscular ketamine (100 mg/kg). We measured blood pressure, rectal temperature and lung perfusion using radioscintigraphy with a technetium colloid indicator. The systolic blood pressure was decreased 75% by removing blood via v. jugularis in the first three groups and group 4 was accepted as the control group, and blood volume was not diminished. Then the first three groups were resuscitated with autologous blood containing 125 units heparine/ml in group 1, saline in group 2, and hydroxyethyl starch (HES) 6% in group 3. After the correction of hypovolemia, all animals were injected 100 Bg (0.1 cc) technetium 99m macroaggregated albumin ({sup 99m}Tc MAA) via penil vein. After injection of {sup 99m}Tc MAA, 3 minutes fixed images were detected by a {gamma} camera in posterior position at 15 minutes and 5 hours. {sup 99m}Tc MMA ''wash out'' rate in lung was determined quantitatively at 5 hours. Compared to a control group, lung perfusion was decreased significantly in groups resuscitated with saline, and HES 6% while perfusion was restored with autologous blood. We conclude that heparinized autologous blood saved lung capillary circulation in hemorrhagic shock in rats. (author)

  11. Esophageal blood flow in the cat. Normal distribution and effects of acid perfusion

    International Nuclear Information System (INIS)

    Hollwarth, M.E.; Smith, M.; Kvietys, P.R.; Granger, D.N.

    1986-01-01

    The radioactive microsphere technique was used to estimate blood flow to different regions of the esophagus and to adjacent regions of the stomach before and after perfusion of the esophagus with hydrochloric acid (pH 1.5) for 5 min. Under resting conditions total blood flow, as well as blood flow to the mucosal-submucosal layer and the muscular layer, to both sphincters was significantly higher than to the esophageal body. Blood flow to the adjacent regions of the stomach was significantly higher than esophageal blood flow. Acid perfusion resulted in a large increase in total blood flow in both sphincters and the lower esophageal body. Gastric blood flow was not altered by acid perfusion. The esophageal hyperemia resulted primarily from an increase in blood flow to the muscular layer; mucosal-submucosal blood flow was increased only in the lower esophageal sphincter. The present study indicates that short periods (5 min) of gastroesophageal reflux may increase esophageal blood flow

  12. Reproducibility of Dynamic Computed Tomography Brain Perfusion Measurements in Patients with Significant Carotid Artery Stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Serafin, Z.; Kotarski, M.; Karolkiewicz, M.; Mindykowski, R.; Lasek, W.; Molski, S.; Gajdzinska, M.; Nowak-Nowacka, A. (Dept. of Radiology and Diagnostic Imaging, and Dept. of General and Vascular Surgery, Nicolaus Copernicus Univ., Collegium Medicum, Bydgoszcz (Poland))

    2009-02-15

    Background: Perfusion computed tomography (PCT) determination is a minimally invasive and widely available technique for brain blood flow assessment, but its application may be restricted by large variation of results. Purpose: To determine the intraobserver, interobserver, and inter examination variability of brain PCT absolute measurements in patients with significant carotid artery stenosis (CAS), and to evaluate the effect of the use of relative perfusion values on PCT reproducibility. Material and Methods: PCT imaging was completed in 61 patients before endarterectomy, and in 38 of these within 4 weeks after treatment. Cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), and peak enhancement intensity (PEI) were calculated with the maximum slope method. Inter examination variability was evaluated based on perfusion of hemisphere contralateral to the treated CAS, from repeated examinations. Interobserver and intraobserver variability were established for the untreated side, based on pretreatment examination. Results: Interobserver and intraobserver variability were highest for CBF measurement (28.8% and 32.5%, respectively), and inter examination variability was the highest for CBV (24.1%). Intraobserver and interobserver variability were higher for absolute perfusion values compared with their respective ratios for CBF and TTP. The only statistically significant difference between perfusion values measured by two observers was for CBF (mean 78.3 vs. 67.5 ml/100 g/min). The inter examination variability of TTP (12.1%) was significantly lower than the variability of other absolute perfusion measures, and the inter examination variability of ratios was significantly lower than absolute values for all the parameters. Conclusion: In longitudinal studies of patients with chronic cerebral ischemia, PCT ratios and either TTP or CBV are more suitable measures than absolute CBF values, because of their considerably lower inter- and intraobserver

  13. Reproducibility of Dynamic Computed Tomography Brain Perfusion Measurements in Patients with Significant Carotid Artery Stenosis

    International Nuclear Information System (INIS)

    Serafin, Z.; Kotarski, M.; Karolkiewicz, M.; Mindykowski, R.; Lasek, W.; Molski, S.; Gajdzinska, M.; Nowak-Nowacka, A.

    2009-01-01

    Background: Perfusion computed tomography (PCT) determination is a minimally invasive and widely available technique for brain blood flow assessment, but its application may be restricted by large variation of results. Purpose: To determine the intraobserver, interobserver, and inter examination variability of brain PCT absolute measurements in patients with significant carotid artery stenosis (CAS), and to evaluate the effect of the use of relative perfusion values on PCT reproducibility. Material and Methods: PCT imaging was completed in 61 patients before endarterectomy, and in 38 of these within 4 weeks after treatment. Cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), and peak enhancement intensity (PEI) were calculated with the maximum slope method. Inter examination variability was evaluated based on perfusion of hemisphere contralateral to the treated CAS, from repeated examinations. Interobserver and intraobserver variability were established for the untreated side, based on pretreatment examination. Results: Interobserver and intraobserver variability were highest for CBF measurement (28.8% and 32.5%, respectively), and inter examination variability was the highest for CBV (24.1%). Intraobserver and interobserver variability were higher for absolute perfusion values compared with their respective ratios for CBF and TTP. The only statistically significant difference between perfusion values measured by two observers was for CBF (mean 78.3 vs. 67.5 ml/100 g/min). The inter examination variability of TTP (12.1%) was significantly lower than the variability of other absolute perfusion measures, and the inter examination variability of ratios was significantly lower than absolute values for all the parameters. Conclusion: In longitudinal studies of patients with chronic cerebral ischemia, PCT ratios and either TTP or CBV are more suitable measures than absolute CBF values, because of their considerably lower inter- and intraobserver

  14. Fast Doppler as a novel bedside measure of cerebral perfusion in preterm infants.

    Science.gov (United States)

    Peeples, Eric S; Mehic, Edin; Mourad, Pierre D; Juul, Sandra E

    2016-02-01

    Altered cerebral perfusion from impaired autoregulation may contribute to the morbidity and mortality associated with premature birth. We hypothesized that fast Doppler imaging could provide a reproducible bedside estimation of cerebral perfusion and autoregulation in preterm infants. This is a prospective pilot study using fast Doppler ultrasound to assess blood flow velocity in the basal ganglia of 19 subjects born at 26-32 wk gestation. Intraclass correlation provided a measure of test-retest reliability, and linear regression of cerebral blood flow velocity and heart rate or blood pressure allowed for estimations of autoregulatory ability. The intraclass correlation when imaging in the first 48 h of life was 0.634. We found significant and independent correlations between the systolic blood flow velocity and both systolic blood pressure and heart rate (P = 0.015 and 0.012 respectively) only in the 26-28 wk gestational age infants in the first 48 h of life. Our results suggest that fast Doppler provides reliable bedside measurements of cerebral blood flow velocity at the tissue level in premature infants, acting as a proxy for cerebral tissue perfusion. Additionally, autoregulation appears to be impaired in the extremely preterm infants, even within a normal range of blood pressures.

  15. Contrast-enhanced ultrasonography to assess blood perfusion of skeletal muscles in normal dogs

    Science.gov (United States)

    OH, Juyeon; JEON, Sunghoon; CHOI, Jihye

    2015-01-01

    This study evaluated perfusion of skeletal muscle using contrast enhanced ultrasonography in humerus, radius, femur and tibia in normal dogs. Contrast enhanced ultrasonography for each region was performed after injecting 0.5 mL and 1 mL of contrast medium (SonoVue) in every dog. Blood perfusion was assessed quantitatively by measuring the peak intensity, time to the peak intensity and area under the curve from the time–intensity curve. Vascularization in skeletal muscle was qualitatively graded with a score of 0–3 according to the number of vascular signals. A parabolic shape of time–intensity curve was observed from muscles in normal dogs, and time to the peak intensity, the peak intensity and area under the curve of each muscle were not significantly different according to the appendicular regions examined and the dosage of contrast agent administered. This study reports that feasibility of contrast enhanced ultrasonography for assessment of the muscular perfusion in canine appendicular regions. PMID:25754794

  16. Misery perfusion, blood pressure control, and 5-year stroke risk in symptomatic major cerebral artery disease.

    Science.gov (United States)

    Yamauchi, Hiroshi; Kagawa, Shinya; Kishibe, Yoshihiko; Takahashi, Masaaki; Higashi, Tatsuya

    2015-01-01

    The benefit of strict blood pressure (BP) control in high-risk patients with symptomatic major cerebral artery disease and misery perfusion (MP) is controversial. Our purposes were (1) to determine whether MP is a predictor of a 5-year risk of subsequent stroke and (2) to investigate the relationships among BP during follow-up, MP, and the stroke risk. We studied 130 nondisabled patients with symptomatic major cerebral artery disease. Baseline hemodynamic measurements were obtained from (15)O-gas positron emission tomography, and patients received medical treatment and they were followed for 5 years or until stroke recurrence or death. During 5 years, strokes occurred in 6 of 16 patients with MP and in 15 of 114 without MP (log-rank test; Pstrokes in patients with MP and 4 in those without MP (Pstroke declined markedly after 2 years, and there was only 1 ipsilateral ischemic stroke in a patient without MP. Normal systolic BP (strokes in patients with impaired perfusion (including MP), whereas systolic BP outside the 130 to 149 mm Hg range was associated with an increased risk of all strokes in patients without MP. Patients with MP showed a high-5-year stroke recurrence, but a large part of the 5-year stroke risk disappeared after 2 years. Aggressive BP control may be hazardous in patients with impaired perfusion, including MP. © 2014 American Heart Association, Inc.

  17. Prediction of residual lung function after lung surgery, and examination of blood perfusion in the pre- and postoperative lung using three-dimensional SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Shimatani, Shinji [Toho Univ., Tokyo (Japan). School of Medicine

    2001-01-01

    In order to predict postoperative pulmonary function after lung surgery, preoperative {sup 99m}Tc-macroaggregated albumin (MAA) lung perfusion scans with single-photon emission computed tomography (SPECT) were performed. Spirometry was also performed before and 4-6 months after surgery in 40 patients. In addition, changes in blood perfusion in the pre- and postoperative lung were examined by postoperative lung perfusion scans in 18 of the 40 patients. We measured the three-dimensional (3-D) imaging volume of the operative and contralateral lungs using the volumes rendering method at blood perfusion thresholds of 20, 50 and 75%, utilizing {sup 99m}Tc-MAA lung perfusion, and predicted pulmonary function by means of the measured volumes. We examined the correlation between predicted and the measured values of postoperative pulmonary function, forced vital capacity (FVC) and forced expiratory volume in one second (FEV{sub 1.0}). The correlation between FEV{sub 1.0} predicted by SPECT (threshold 50%) and measured postoperative lung function resembled that between lung function predicted by the standard planar method and measured FEV{sub 1.0} in the lobectomy group. We then examined the ratios of both pre- and postoperative blood perfusion volumes obtained using 3-D imaging at lung perfusion threshold ranges of 10% each (PV20-29, PV30-39) to pre- and postoperative total perfusion (PV20-100). In the lobectomy group, the postoperative PV20-29/PV20-100 value was significantly higher for the operative side lung than the preoperative PV20-29/PV20-100 value, and the postoperative PV50-59, 60-69, 70-79, 80-89 and 90-100/PV20-100 values were significantly lower than the respective preoperative values. However, in the contralateral lung, the respective pre- and postoperative PV/PV20-100 values were almost identical. These findings suggest that the rate of low blood perfusion increased while the rate of middle to high perfusion decreased in the lobectomy group in the operative

  18. Prolonged preservation of the blood-perfused canine heart with glycolysis-promoting solution.

    Science.gov (United States)

    Takeuchi, K; Cao-Danh, H; Kawai, A; Ohkado, A; Konishi, H; McGowan, F X; del Nido, P J

    1999-09-01

    Prolonged ischemia and inadequate myocardial preservation remain significant perioperative risk factors in cardiac transplantation. Long-term preservation techniques that have been effective in small rodent hearts have not been as effective in larger animal models or in clinical studies. We developed a cardioplegia solution formulated to promote high-energy phosphate production from glycolysis and determined its efficacy in a blood perfused canine heart model subjected to 24 hours of ischemia. Hearts harvested from adult dogs (n = 6 per group) were flushed with a histidine-buffered cardioplegia solution containing glucose or University of Wisconsin solution. The hearts were maintained at 4 degrees C for 24 hours then reperfused with autologous blood. After reperfusion, left ventricular pressures were measured with an intracavitary balloon at varying balloon volumes and compared with control nonischemic hearts. Predicted stroke volume and ejection fraction were calculated at an end-systolic pressure of 70 mm Hg and end-diastolic pressure of 15 mm Hg. Developed pressure was better preserved in the hearts that received histidine-buffered solution (93+/-9 versus 38+/-7 mm Hg, pglycolysis-promoting cardioplegia solution provided effective preservation of the blood perfused canine heart with superior recovery of pump performance after 24 hours of hypothermic ischemia compared with University of Wisconsin solution in this model.

  19. Skin perfusion pressure on the legs measured as the external pressure required for skin reddening after blanching

    DEFF Research Database (Denmark)

    Holstein, P; Nielsen, P.E.; Lund, P

    1980-01-01

    The skin perfusion on the calf was measured photo-electrically and by isotope washout technique using external counter pressure by a blood pressure cuff. By the photocell the skin blanching threshold external pressure (BTEP) was recorded on histamine flared red skin. By isotope washout technique......Hg (SD 8.7). As compared to the intra-arterial blood pressure the BTEP was found to lie close to the mean blood pressure in normal subjects as well as in hypertensive subjects. The present data indicate that the skin perfusion pressure on the legs can be measured by the rapid photo-electric technique...

  20. Patient-specific coronary blood supply territories for quantitative perfusion analysis.

    Science.gov (United States)

    Zakkaroff, Constantine; Biglands, John D; Greenwood, John P; Plein, Sven; Boyle, Roger D; Radjenovic, Aleksandra; Magee, Derek R

    2018-01-01

    Myocardial perfusion imaging, coupled with quantitative perfusion analysis, provides an important diagnostic tool for the identification of ischaemic heart disease caused by coronary stenoses. The accurate mapping between coronary anatomy and under-perfused areas of the myocardium is important for diagnosis and treatment. However, in the absence of the actual coronary anatomy during the reporting of perfusion images, areas of ischaemia are allocated to a coronary territory based on a population-derived 17-segment (American Heart Association) AHA model of coronary blood supply. This work presents a solution for the fusion of 2D Magnetic Resonance (MR) myocardial perfusion images and 3D MR angiography data with the aim to improve the detection of ischaemic heart disease. The key contribution of this work is a novel method for the mediated spatiotemporal registration of perfusion and angiography data and a novel method for the calculation of patient-specific coronary supply territories. The registration method uses 4D cardiac MR cine series spanning the complete cardiac cycle in order to overcome the under-constrained nature of non-rigid slice-to-volume perfusion-to-angiography registration. This is achieved by separating out the deformable registration problem and solving it through phase-to-phase registration of the cine series. The use of patient-specific blood supply territories in quantitative perfusion analysis (instead of the population-based model of coronary blood supply) has the potential of increasing the accuracy of perfusion analysis. Quantitative perfusion analysis diagnostic accuracy evaluation with patient-specific territories against the AHA model demonstrates the value of the mediated spatiotemporal registration in the context of ischaemic heart disease diagnosis.

  1. Patient-specific coronary blood supply territories for quantitative perfusion analysis

    Science.gov (United States)

    Zakkaroff, Constantine; Biglands, John D.; Greenwood, John P.; Plein, Sven; Boyle, Roger D.; Radjenovic, Aleksandra; Magee, Derek R.

    2018-01-01

    Abstract Myocardial perfusion imaging, coupled with quantitative perfusion analysis, provides an important diagnostic tool for the identification of ischaemic heart disease caused by coronary stenoses. The accurate mapping between coronary anatomy and under-perfused areas of the myocardium is important for diagnosis and treatment. However, in the absence of the actual coronary anatomy during the reporting of perfusion images, areas of ischaemia are allocated to a coronary territory based on a population-derived 17-segment (American Heart Association) AHA model of coronary blood supply. This work presents a solution for the fusion of 2D Magnetic Resonance (MR) myocardial perfusion images and 3D MR angiography data with the aim to improve the detection of ischaemic heart disease. The key contribution of this work is a novel method for the mediated spatiotemporal registration of perfusion and angiography data and a novel method for the calculation of patient-specific coronary supply territories. The registration method uses 4D cardiac MR cine series spanning the complete cardiac cycle in order to overcome the under-constrained nature of non-rigid slice-to-volume perfusion-to-angiography registration. This is achieved by separating out the deformable registration problem and solving it through phase-to-phase registration of the cine series. The use of patient-specific blood supply territories in quantitative perfusion analysis (instead of the population-based model of coronary blood supply) has the potential of increasing the accuracy of perfusion analysis. Quantitative perfusion analysis diagnostic accuracy evaluation with patient-specific territories against the AHA model demonstrates the value of the mediated spatiotemporal registration in the context of ischaemic heart disease diagnosis. PMID:29392098

  2. [Study on optimal selection of structure of vaneless centrifugal blood pump with constraints on blood perfusion and on blood damage indexes].

    Science.gov (United States)

    Hu, Zhaoyan; Pan, Youlian; Chen, Zhenglong; Zhang, Tianyi; Lu, Lijun

    2012-12-01

    This paper is aimed to study the optimal selection of structure of vaneless centrifugal blood pump. The optimal objective is determined according to requirements of clinical use. Possible schemes are generally worked out based on structural feature of vaneless centrifugal blood pump. The optimal structure is selected from possible schemes with constraints on blood perfusion and blood damage indexes. Using an optimal selection method one can find the optimum structure scheme from possible schemes effectively. The results of numerical simulation of optimal blood pump showed that the method of constraints of blood perfusion and blood damage is competent for the requirements of selection of the optimal blood pumps.

  3. Analysis of decrease in lung perfusion blood volume with occlusive and non-occlusive pulmonary embolisms

    International Nuclear Information System (INIS)

    Ikeda, Yohei; Yoshimura, Norihiko; Hori, Yoshiro; Horii, Yosuke; Ishikawa, Hiroyuki; Yamazaki, Motohiko; Noto, Yoshiyuki; Aoyama, Hidefumi

    2014-01-01

    Highlights: • The proportion of preserved PE lesions in the non-occlusive group was 76.7% (33/43). • HUs of the iodine map were significantly higher in the non-occlusive group than in the occlusive group. • There was no significant difference in HUs between the non-occlusive and corresponding normal group. - Abstract: Purpose: The aim of this study was to determine if lung perfusion blood volume (lung PBV) with non-occlusive pulmonary embolism (PE) differs quantitatively and visually from that with occlusive PE and to investigate if lung PBV with non-occlusive PE remains the same as that without PE. Materials and methods: Totally, 108 patients suspected of having acute PE underwent pulmonary dual-energy computed tomography angiography (DECTA) between April 2011 and January 2012. Presence of PE on DECTA was evaluated by one radiologist. Two radiologists visually evaluated the PE distribution (segmental or subsegmental) and its nature (occlusive or non-occlusive) on DECTA and classified perfusion in lung PBV as “decreased,” “slightly decreased,” and “preserved”. Two radiologists used a lung PBV application to set a region of interest (ROI) in the center of the lesion and measured HU values of an iodine map. In the same slice as the ROI of the lesion and close to the lesion, another ROI was set in the normal perfusion area without PE, and HUs were measured. The proportion of lesions was compared between the occlusive and non-occlusive groups. HUs were compared among the occlusive, non-occlusive, and corresponding normal groups. Results: Twenty-five patients had 80 segmental or subsegmental lesions. There were 37 and 43 lesions in the occlusive and non-occlusive groups, respectively. The proportion of decreased lesions was 73.0% (27/37) in the occlusive group, while that of preserved lesions in the non-occlusive group was 76.7% (33/43). There was a significant difference in the proportion of lesions (P < 0.001) between the two groups. HUs of the

  4. Captopril improves tumor nanomedicine delivery by increasing tumor blood perfusion and enlarging endothelial gaps in tumor blood vessels.

    Science.gov (United States)

    Zhang, Bo; Jiang, Ting; Tuo, Yanyan; Jin, Kai; Luo, Zimiao; Shi, Wei; Mei, Heng; Hu, Yu; Pang, Zhiqing; Jiang, Xinguo

    2017-12-01

    Poor tumor perfusion and unfavorable vessel permeability compromise nanomedicine drug delivery to tumors. Captopril dilates blood vessels, reducing blood pressure clinically and bradykinin, as the downstream signaling moiety of captopril, is capable of dilating blood vessels and effectively increasing vessel permeability. The hypothesis behind this study was that captopril can dilate tumor blood vessels, improving tumor perfusion and simultaneously enlarge the endothelial gaps of tumor vessels, therefore enhancing nanomedicine drug delivery for tumor therapy. Using the U87 tumor xenograft with abundant blood vessels as the tumor model, tumor perfusion experiments were carried out using laser Doppler imaging and lectin-labeling experiments. A single treatment of captopril at a dose of 100 mg/kg significantly increased the percentage of functional vessels in tumor tissues and improved tumor blood perfusion. Scanning electron microscopy of tumor vessels also indicated that the endothelial gaps of tumor vessels were enlarged after captopril treatment. Immunofluorescence-staining of tumor slices demonstrated that captopril significantly increased bradykinin expression, possibly explaining tumor perfusion improvements and endothelial gap enlargement. Additionally, imaging in vivo, imaging ex vivo and nanoparticle distribution in tumor slices indicated that after a single treatment with captopril, the accumulation of 115-nm nanoparticles in tumors had increased 2.81-fold with a more homogeneous distribution pattern in comparison to non-captopril treated controls. Finally, pharmacodynamics experiments demonstrated that captopril combined with paclitaxel-loaded nanoparticles resulted in the greatest tumor shrinkage and the most extensive necrosis in tumor tissues among all treatment groups. Taken together, the data from the present study suggest a novel strategy for improving tumor perfusion and enlarging blood vessel permeability simultaneously in order to improve

  5. Cerebral blood volume imaging by flat detector computed tomography in comparison to conventional multislice perfusion CT

    International Nuclear Information System (INIS)

    Struffert, Tobias; Kloska, Stephan; Engelhorn, Tobias; Doerfler, Arnd; Deuerling-Zheng, Yu; Boese, Jan; Zellerhoff, Michael; Schwab, Stefan

    2011-01-01

    We tested the hypothesis that Flat Detector computed tomography (FD-CT) with intravenous contrast medium would allow the calculation of whole brain cerebral blood volume (CBV) mapping (FD-CBV) and would correlate with multislice Perfusion CT (PCT). Twenty five patients were investigated with FD-CBV and PCT. Correlation of the CBV maps of both techniques was carried out with measurements from six anatomical regions from both sides of the brain. Mean values of each region and the correlation coefficient were calculated. Bland-Altman analysis was performed to compare the two different imaging techniques. The image and data quality of both PCT and FD-CBV were suitable for evaluation in all patients. The mean CBV values of FD-CBV and PCT showed only minimal differences with overlapping standard deviation. The correlation coefficient was 0.79 (p < 0.01). Bland-Altman analysis showed a mean difference of -0.077 ± 0.48 ml/100 g between FD-CBV and PCT CBV measurements, indicating that FD-CBV values were only slightly lower than those of PCT. CBV mapping with intravenous contrast medium using Flat Detector CT compared favourably with multislice PCT. The ability to assess cerebral perfusion within the angiographic suite may improve the management of ischaemic stroke and evaluation of the efficacy of dedicated therapies. (orig.)

  6. Measurement of cerebral perfusion and haemodynamic reserve by SPECT: application to cerebrovascular disease

    International Nuclear Information System (INIS)

    Steinling, M.

    1990-01-01

    The isolated measurement of cerebral blood flow can lead to gross errors in vascular disease, particularly ischaemic disease, because of disruption of the relations between blood flow and metabolism. In contrast, the measurement of cerebral blood flow combined with measurement of the haemodynamic reserve overcomes these difficulties, regardless of the method of evaluation: reactivity to CO 2 or to acetazolamide; measurement of the flow volume ratio. The author demonstrates that these measurements are even more valuable in situations in which morphological examinations (MRI or computed tomography) are of little value: transient ischaemic attacks, asymptomatic carotid artery stenosis, etc. However, these measurements are useful in constituted infarctions or in vasospasm to assess the distant effects or to guide the therapeutic adjustment or even to provide prognostic elements. Combined measurement of perfusion and haemodynamic reserve, although it does not constitute a formal proof, is now largely accessible by means of non-specialized gamma cameras with determination of the flow/volume ratio [fr

  7. Measurement of cerebral perfusion and haemodynamic reserve by SPECT: application to cerebrovascular disease

    International Nuclear Information System (INIS)

    Steinling, M.

    1990-01-01

    The isolated measurement of cerebral blood flow can lead to gross errors in vascular disease, particularly ischaemic disease, because of disruption of the relations between blood flow and metabolism. In contrast, the measurement of cerebral blood flow combined with measurement of the haemodynamic reserve overcomes these difficulties, regardless of the method of evaluation: reactivity to CO 2 or to acetazolamide; measurement of the flow/volume ratio. The author demonstrates that these measurements are even more valuable in situations in which morphological examinations (MRI or computed tomography) are of little value: transient ischaemic attacks, asymptomatic carotid artery stenosis, etc. However, these measurements are useful in constituted infarctions or in vasospasm to assess the distant effects or to guide the therapeutic adjustment or even to provide prognostic elements. Combined measurement of perfusion and haemodynamic reserve, although it does not constitute a formal proof, is now largely accessible by means of non-specialized gamma cameras with determination of the flow/volume ratio [fr

  8. Photoplethysmographic sensors for perfusion measurements in spinal cord tissue

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, J P; Kyriacou, P A, E-mail: Justin.Phillips.1@city.ac.uk [School of Engineering and Mathematical Sciences, City University London, EC1V 0HB (United Kingdom)

    2011-08-17

    Sensors for recording photoplethysmographic signals from the nervous tissue of the spinal cord are described. The purpose of these sensors is to establish whether perfusion is compromised in various states of injury which occur in certain animal models of spinal cord injury, for example compression injury. Various measures of perfusion are applicable such as the amplitude of the photoplethysmograph signal and the oxygen saturation, measured using a dual wavelength configuration. Signals are usually compared to baseline measurements made in uninjured subjects. This paper describes two types of probe, one based on optical fibres, and one in which optotes are placed in direct contact with the tissue surface. Results from a study based on a compression model utilising a fibreoptic sensor are presented.

  9. 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.

  10. In vitro fabrication of functional three-dimensional tissues with perfusable blood vessels.

    Science.gov (United States)

    Sekine, Hidekazu; Shimizu, Tatsuya; Sakaguchi, Katsuhisa; Dobashi, Izumi; Wada, Masanori; Yamato, Masayuki; Kobayashi, Eiji; Umezu, Mitsuo; Okano, Teruo

    2013-01-01

    In vitro fabrication of functional vascularized three-dimensional tissues has been a long-standing objective in the field of tissue engineering. Here we report a technique to engineer cardiac tissues with perfusable blood vessels in vitro. Using resected tissue with a connectable artery and vein as a vascular bed, we overlay triple-layer cardiac cell sheets produced from coculture with endothelial cells, and support the tissue construct with media perfused in a bioreactor. We show that endothelial cells connect to capillaries in the vascular bed and form tubular lumens, creating in vitro perfusable blood vessels in the cardiac cell sheets. Thicker engineered tissues can be produced in vitro by overlaying additional triple-layer cell sheets. The vascularized cardiac tissues beat and can be transplanted with blood vessel anastomoses. This technique may create new opportunities for in vitro tissue engineering and has potential therapeutic applications.

  11. Increased brainstem perfusion, but no blood-brain barrier disruption, during attacks of migraine with aura

    DEFF Research Database (Denmark)

    Hougaard, Anders; Amin, Faisal M; Christensen, Casper E

    2017-01-01

    symptoms are related to the headache phase of migraine. Animal studies suggest that cortical spreading depression, the likely mechanism of migraine aura, causes disruption of the blood-brain barrier and noxious stimulation of trigeminal afferents leading to activation of brainstem nuclei and triggering...... of migraine headache. We used the sensitive and validated technique of dynamic contrast-enhanced high-field magnetic resonance imaging to simultaneously investigate blood-brain barrier permeability and tissue perfusion in the brainstem (at the level of the lower pons), visual cortex, and brain areas......-free day. The mean time from attack onset to scanning was 7.6 h. We found increased brainstem perfusion bilaterally during migraine with aura attacks. Perfusion also increased in the visual cortex and posterior white matter following migraine aura. We found no increase in blood-brain barrier permeability...

  12. Perfusion measurements with radioactively labelled microspheres

    International Nuclear Information System (INIS)

    Schosser, R.

    1980-01-01

    The technique and the evaluation of the microsphere-method are comprehensively represented in theory and practice. Some changes and new concepts are discussed, besides the known foundations and techniques, that assure an essential methodic improvement resp. practical simplifications. Two new formulas are derived within the frame of the theoretical principles, by which the absolute flux of shorts can be calculated, i.e. on the one hand in the case of known and on the other hand in the case of unknown applied amount of indicator. The determination of the optimal indicator dose is defined and formulated mathematically with respect to the experimental conditions to be expected. The matrix method was designed for the analysis of complex gamma spectra. Hereby there is no selective error accumulation in the case of low energy radio nuclids contrary to the so far exclusively used stripping technique. The number of possible error quantities was reduced by one resp. two variables. The error of particular radio nuclid components is quantitatively computed as standard deviation by means of the theory of approximated systems of linear equations. The external measurement of distance was developed. This technique is less susceptible for errors as the aliquota i.e. whole body measurement technique. Additionally less measurement time is needed. A flexible computer program for a desk top computer was developped for the evaluation. The data from the gamma spectrometer are recorded on tipe and automatically read in by the computer. The manual input are limited to the weights of the organs and some control parameter. The output is made by a clearly arranged table by means of a lineprinter. (orig./MG) [de

  13. [Evaluation of the blood flow in common hepatic tumors by multi-slice spiral CT whole-liver perfusion imaging].

    Science.gov (United States)

    Li, Mengdi; Chen, Yong; Gao, Zhiling; Zhu, Kai; Yin, Xin

    2015-12-01

    To study the characteristics of blood flow in common hepatic tumors by 256-slice spiral CT whole-liver perfusion imaging. Seventy-one patients with hepatic tumors were examined retrospectively by 256-slice spiral CT whole-liver perfusion. Among them, twenty-seven cases were of primary hepatic cancer, twenty-four cases of hepatic hemangioma, and twenty cases of hepatic metastases.Regions of interest (ROIs) were placed in the tumor parenchyma (Area A), peritumoral hepatic parenchyma (Area B), and normal hepatic parenchyma (Area C), respectively. The time density curves (TDC) were drawn, and perfusion parameters including hepatic arterial perfusion(HAP), portal venous perfusion(PVP), total liver perfusion(TLP) and hepatic erfusion index(HPI) were obtained. The values of ROIs were measured, and the perfusion parameters in the areas A, B, C of different hepatic tumors were statistically analyzed. The values of HAP, PVP, HPI in the tumor parenchyma of primary hepatic carcinoma were (20.00 ± 11.41)ml · min(-1) · 100 ml(-1,) (32.31 ± 21.06)ml · min(-1) · 100 ml(-1,) (52.31 ± 30.55)ml · min(-1) · 100 ml(-1,) and (39.67 ± 11.19)%, showing significant difference as compared with those in peritumoral hepatic parenchyma and in normal hepatic parenchyma(PHAP, TLP, and HPI in the tumor parenchyma of hepatic hemangioma were (40.39 ± 29.23)ml · min(-1) · 100 ml(-1,) (132.72 ± 132.65) ml · min(-1) · 100 ml(-1,) and (35.51 ± 15.12)%, were significantly different as compared with those in the peritumoral hepatic parenchyma and in normal hepatic parenchyma(PHAP, PVP, HPI in the tumor parenchyma of hepatic metastases were (17.43 ± 12.27)ml · min(-1) · 100 ml(-1,) (36.19 ± 34.99) ml · min(-1) · 100 ml(-1,) and (37.86 ± 14.49)%, significantly different as compared normal hepatic parenchyma (PHAP, PVP, and TLP of tumor tissue and the PVP and HPI of peritumoral tissue in different hepatic tumors were statistically significantly different (P<0.05). The multi

  14. Skin perfusion pressure measured by isotope washout in legs with arterial occlusive disease. Evaluation of different tracers, comparison to segmental systolic pressure, angiography and transcutaneous oxygen tension and variations during changes in systemic blood pressure

    DEFF Research Database (Denmark)

    Holstein, P; Trap-Jensen, J; Bagger, H

    1983-01-01

    in legs with arterial occlusions at two levels or more; (4) In 47 legs with AOD, the SPP on the calf or on the thigh was compared with transcutaneously measured pO2. The two different methods correlated statistically significant, but the scatter was great; (5) During induced variations in systemic blood...... that 99Tcm is as suitable as the 131I- -labelled tracers in estimating the SPP. The SPP is significantly correlated to skin blood flow, to systolic blood pressure, to tc pO2 and to angiographic findings. Correction of SPP for systemic blood pressure changes can be made in proportion with the measured...... variations in systemic mean blood pressure, but only for groups of patients....

  15. Blood-brain barrier permeability imaging using perfusion computed tomography

    Directory of Open Access Journals (Sweden)

    Avsenik Jernej

    2015-06-01

    Full Text Available Background. The blood-brain barrier represents the selective diffusion barrier at the level of the cerebral microvascular endothelium. Other functions of blood-brain barrier include transport, signaling and osmoregulation. Endothelial cells interact with surrounding astrocytes, pericytes and neurons. These interactions are crucial to the development, structural integrity and function of the cerebral microvascular endothelium. Dysfunctional blood-brain barrier has been associated with pathologies such as acute stroke, tumors, inflammatory and neurodegenerative diseases.

  16. Dynamic Susceptibility Contrast Perfusion Magnetic Resonance Imaging Demonstrates Reduced Periventricular Cerebral Blood Flow in Dogs with Ventriculomegaly

    Directory of Open Access Journals (Sweden)

    Martin J. Schmidt

    2017-08-01

    Full Text Available The nature of ventriculomegaly in dogs is still a matter of debate. Signs of increased intraventricular pressure and atrophy of the cerebral white matter have been found in dogs with ventriculomegaly, which would imply increased intraventricular pressure and, therefore, a pathological condition, i.e., to some extent. Reduced periventricular blood flow was found in people with high elevated intraventricular pressure. The aim of this study was to compare periventricular brain perfusion in dogs with and without ventriculomegaly using perfusion weighted-magnetic-resonance-imaging to clarify as to whether ventriculomegaly might be associated with an increase in intraventricular pressure. Perfusion was measured in 32 Cavalier King Charles spaniels (CKCS with ventriculomegaly, 10 CKCSs were examined as a control group. Cerebral blood flow (CBF was measured using free-hand regions of interest (ROI in five brain regions: periventricular white matter, caudate nucleus, parietal cortex, hippocampus, and thalamus. CBF was significantly lower in the periventricular white matter of the dogs with ventriculomegaly (p = 0.0029 but not in the other ROIs. Reduction of periventricular CBF might imply increase of intraventricular pressure in ventriculomegaly.

  17. Factors affecting the lung perfused blood volume in patients with intrapulmonary clots after anti-coagulation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Munemasa, E-mail: radokada@yamaguchi-u.ac.jp [Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Masuda, Yu [4th Grade of 6-year Medicine Doctor Program, Department of Medicine, Yamaguchi University Faculty of Medicine and Health Sciences 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Nakashima, Yoshiteru [Department of Radiology, Yamaguchi Grand Medical Center, Oosaki 77, Hofu, Yamaguchi 747-8511 (Japan); Nomura, Takafumi; Nakao, Sei [Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Suga, Kazuyoshi [Department of Radiology, St Hills Hospital, Imamurakita 3-7-18, Ube, Yamaguchi 755-0155 (Japan); Kido, Shoji [Computer-aided Diagnosis and Biomedical Imaging Research Biomedical Engineering, Applied Medical Engineering Science Graduate School of Medicine, Yamaguchi University, Tokiwadai 2-16-1, Ube, Yamaguchi 755-8611 (Japan); Matsunaga, Naofumi [Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan)

    2015-08-15

    Highlights: • Dual-energy CT can provide morphological and functional lung images in the same examination. • The subsequent dual-energy CT demonstrates the increased whole lung perfused blood volume (V{sub 120}) despite the residual intrapulmonary clots after treatment in one examination. • The increased whole lung perfusion (V{sub 120}) and a decreased low perfusion volume (V{sub 5}) result in the improvement in the low perfusion rate (%V{sub 5}) in the patients with acute pulmonary embolism after treatment. - Abstract: Objectives: Factors affecting the improvement in the lung perfused blood volume (LPBV) were evaluated based on the presence of intrapulmonary clots (IPCs) after anti-coagulation therapy using 64-slice dual-energy CT. Materials and methods: 96 patients exhibiting venous thromboembolism underwent initial and repeated LPBV examinations between December 2008 and July 2014. Fifteen patients were excluded due to pulmonary comorbidities, and a total of 81 patients were included in this study. Acute pulmonary embolism (PE) was diagnosed in 46 of the patients (56.7%). LPBV images were three-dimensionally reconstructed with two threshold ranges: 1–120 HU (V{sub 120}) and 1–5 HU (V{sub 5}), and the relative value of V{sub 5} per V{sub 120} expressed as %V{sub 5}. These values were subsequently compared with indicators of the severity of PE, such as the D-dimer level, heart rate and CT measurements. This study was approved by the local ethics committee. Results: In patients with IPCs, the D-dimer, V{sub 5} and %V{sub 5}values were significantly larger (p ≤ 0.01) in the initial LPBV, although these differences disappeared in subsequent LPBV after treatment. The right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio and %V{sub 5} values were also significantly reduced, whereas the V{sub 5} value did not significantly decrease (p = 0.07), but V{sub 120} value significantly increased (p < 0.001) after treatment. However, in

  18. Abolished ventilation and perfusion of lung caused by blood clot in the left main bronchus

    DEFF Research Database (Denmark)

    Afzelius, P; Bergmann, A; Henriksen, J H

    2015-01-01

    /Q) scintigraphy with single-photon emission CT (SPECT)/CT. V/Q SPECT/CT demonstrated abolished ventilation due to obstruction of the left main bronchus and markedly reduced perfusion of the entire left lung, a condition that was completely reversed after removal of a blood clot. We present the first pictorially......It is generally assumed that the lungs possess arterial autoregulation associated with bronchial obstruction. A patient with pneumonia and congestive heart failure unexpectedly developed frequent haemoptysis. High-resolution CT and diagnostic CT were performed as well as ventilation/perfusion (V...

  19. Effect of blood flow on muscle lactate release studied in perfused rat hindlimb

    DEFF Research Database (Denmark)

    Pilegaard, H; Bangsbo, Jens; Henningsen, P

    1995-01-01

    The influence of blood flow on muscle lactate and H+ release as well as muscle glyconeogenesis was studied in the perfused rat hindlimb. After 2 min of supramaximal stimulation the perfusate flow rate was 7 (F7), 12 (F12), or 18 (F18) ml/min for 30 min. Perfusate samples were drawn frequently...... and muscle samples were obtained before stimulation, immediately after stimulation, and at 3, 10, and 30 min of recovery from soleus, white gastrocnemius (WG) and red gastrocnemius. During the first 5 min of recovery lactate release was 35-39% lower (P F7 than in F12 and F18...... but with no differences in total release during recovery. In F7 the concentration of lactate was higher (P F7 than in F12 and F18. The difference...

  20. Analysis of blood flow in a third ventricular ependymoma and an olfactory bulb meningioma by usisng perfusion computed tomography

    International Nuclear Information System (INIS)

    Kishimoto, M.; Yamada, K.; Seok, J.S.; Shimizu, J.; Kobayashi, Y.; Akiba, Y.; Morishita, Y.; Iwasa, A.; Iwasaki, T.; Miyake, Y.

    2008-01-01

    Brain perfusion computed tomography (CT) scanning was performed in a mongrel dog and a golden retriever that were diagnosed with third ventricular tumor and olfactory bulb tumor, respectively, by contrast-enhanced CT. The tumors were pathologically diagnosed as ependymoma and meningioma, respectively. Perfusion CT results revealed that the ependymoma in this study had a lower blood flow, higher blood volume, and greater transit time of blood than the adjacent brain tissue. Further, the meningioma in this study had a higher blood flow, higher blood volume, and greater transit time of blood than the adjacent brain tissue. Perfusion CT can potentially be used for the grading of brain tumors and narrowing differential diagnosis, provided the perfusion CT data of animals are accumulated

  1. 96 perfusable blood vessels to study vascular permeability in vitro.

    Science.gov (United States)

    van Duinen, V; van den Heuvel, A; Trietsch, S J; Lanz, H L; van Gils, J M; van Zonneveld, A J; Vulto, P; Hankemeier, T

    2017-12-22

    Current in vitro models to test the barrier function of vasculature are based on flat, two-dimensional monolayers. These monolayers do not have the tubular morphology of vasculature found in vivo and lack important environmental cues from the cellular microenvironment, such as interaction with an extracellular matrix (ECM) and exposure to flow. To increase the physiological relevance of in vitro models of the vasculature, it is crucial to implement these cues and better mimic the native three-dimensional vascular architecture. We established a robust, high-throughput method to culture endothelial cells as 96 three-dimensional and perfusable microvessels and developed a quantitative, real-time permeability assay to assess their barrier function. Culture conditions were optimized for microvessel formation in 7 days and were viable for over 60 days. The microvessels exhibited a permeability to 20 kDa dextran but not to 150 kDa dextran, which mimics the functionality of vasculature in vivo. Also, a dose-dependent effect of VEGF, TNFα and several cytokines confirmed a physiologically relevant response. The throughput and robustness of this method and assay will allow end-users in vascular biology to make the transition from two-dimensional to three-dimensional culture methods to study vasculature.

  2. Haemoadsorption reduces the inflammatory response and improves blood flow during ex vivo renal perfusion in an experimental model

    Directory of Open Access Journals (Sweden)

    Sarah A. Hosgood

    2017-10-01

    Full Text Available Abstract Background Ex-vivo normothermic perfusion strategies are a promising new instrument in organ transplantation. The perfusion conditions are designed to be protective however the artificial environment can induce a local inflammatory response. The aim of this study was to determine the effect of incorporating a Cytosorb adsorber into an isolated kidney perfusion system. Methods Porcine kidneys were subjected to 22 h of cold ischaemia then reperfused for 6 h on an ex vivo reperfusion circuit. Pairs of kidneys were randomised to either control (n = 5 or reperfusion with a Cytosorb adsorber (n = 5 integrated into the circuit. Tissue, blood and urine samples were taken for the measurement of inflammation and renal function. Results Baseline levels of cytokines (IL-6, TNFα, IL-8, IL-10, IL-1β, IL-1α were similar between groups. Levels of IL-6 and IL-8 in the perfusate significantly increased during reperfusion in the control group but not in the Cytosorb group (P = 0.023, 0.049. Levels of the other cytokines were numerically lower in the Cytosorb group; however, this did not reach statistical significance. The mean renal blood flow (RBF was significantly higher in the Cytosorb group (162 ± 53 vs. 120 ± 35 mL/min/100 g; P = 0.022. Perfusate levels of prostaglandin E2 were significantly lower in the Cytosorb group (642 ± 762 vs. 3258 ± 980 pg/mL; P = 0.0001. Levels of prostacyclin were significantly lower in the Cytosorb group at 1, 3 and 6 h of reperfusion (P = 0.008, 0.003, 0.0002. Levels of thromboxane were also significantly lower in the Cytosorb group throughout reperfusion (P = 0.005. Haemoadsorption had no effect on creatinine clearance (P = 0.109. Conclusion Haemoadsorption can reduce the inflammatory response and improve renal blood flow during perfusion. Nonetheless, in this model haemoadsorption had no influence on renal function and this may relate to the broad-spectrum action of the Cytosorb

  3. Quantitative arterial spin labelling perfusion measurements in rat models of renal transplantation and acute kidney injury at 3 T

    International Nuclear Information System (INIS)

    Zimmer, Fabian; Schad, Lothar R.; Zoellner, Frank G.; Klotz, Sarah; Hoeger, Simone; Yard, Benito A.; Kraemer, Bernhard K.

    2017-01-01

    To employ ASL for the measurement of renal cortical perfusion in particular renal disorders typically associated with graft loss and to investigate its potential to detect and differentiate the related functional deterioration i.e., in a setting of acute kidney injury (AKI) as well as in renal grafts showing acute and chronic transplant rejection. 14 Lewis rats with unilateral ischaemic AKI and 43 Lewis rats with renal grafts showing acute or chronic rejections were used. All ASL measurements in this study were performed on a 3 T MR scanner using a FAIR True-FISP approach to assess renal blood flow (RBF). Perfusion maps were calculated and the cortical blood flow was determined using a region-of-interest based analysis. RBF of healthy and AKI kidneys as well as of both rejection models, were compared. In a subsample of 20 rats, creatinine clearance was measured and correlated with cortical perfusion. RBF differs significantly between healthy and AKI kidneys (P < 0.001) with a mean difference of 213 ± 80 ml/100 g/min. Renal grafts with chronic rejections show a significantly higher (P < 0.001) mean cortical perfusion (346 ± 112 ml/100 g/min) than grafts with acute rejection (240 ± 66 ml/100 g/min). Both transplantation models have a significantly (P < 0.001) lower perfusion than healthy kidneys. Renal creatinine clearance is significantly correlated (R = 0.85, P < 0.001) with cortical blood flow. Perfusion measurements with ASL have the potential to become a valuable diagnostic tool, regarding the detection of renal impairment and the differentiation of disorders that lead to a loss of renal function and that are typically associated with graft loss.

  4. Quantitative arterial spin labelling perfusion measurements in rat models of renal transplantation and acute kidney injury at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, Fabian; Schad, Lothar R.; Zoellner, Frank G. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Klotz, Sarah; Hoeger, Simone; Yard, Benito A.; Kraemer, Bernhard K. [Heidelberg Univ., Mannheim (Germany). Dept. of Medicine V

    2017-05-01

    To employ ASL for the measurement of renal cortical perfusion in particular renal disorders typically associated with graft loss and to investigate its potential to detect and differentiate the related functional deterioration i.e., in a setting of acute kidney injury (AKI) as well as in renal grafts showing acute and chronic transplant rejection. 14 Lewis rats with unilateral ischaemic AKI and 43 Lewis rats with renal grafts showing acute or chronic rejections were used. All ASL measurements in this study were performed on a 3 T MR scanner using a FAIR True-FISP approach to assess renal blood flow (RBF). Perfusion maps were calculated and the cortical blood flow was determined using a region-of-interest based analysis. RBF of healthy and AKI kidneys as well as of both rejection models, were compared. In a subsample of 20 rats, creatinine clearance was measured and correlated with cortical perfusion. RBF differs significantly between healthy and AKI kidneys (P < 0.001) with a mean difference of 213 ± 80 ml/100 g/min. Renal grafts with chronic rejections show a significantly higher (P < 0.001) mean cortical perfusion (346 ± 112 ml/100 g/min) than grafts with acute rejection (240 ± 66 ml/100 g/min). Both transplantation models have a significantly (P < 0.001) lower perfusion than healthy kidneys. Renal creatinine clearance is significantly correlated (R = 0.85, P < 0.001) with cortical blood flow. Perfusion measurements with ASL have the potential to become a valuable diagnostic tool, regarding the detection of renal impairment and the differentiation of disorders that lead to a loss of renal function and that are typically associated with graft loss.

  5. Blood temperature and perfusion to exercising and non-exercising human limbs

    DEFF Research Database (Denmark)

    González-Alonso, José; Calbet, José A. L.; Boushel, Robert

    2015-01-01

    increased in association with elevations in TB and limb V̇O2, whereas ABF, arm TB and V̇O2 remained largely unchanged. During incremental arm exercise, both ABF and LBF increased in relationship to similar increases in V̇O2. In 12 trained males, increases in femoral TB and LBF during incremental leg......NEW FINDINGS: What is the central question of this study? Temperature-sensitive mechanisms are thought to contribute to blood-flow regulation, but the relationship between exercising and non-exercising limb perfusion and blood temperature is not established. What is the main finding and its...... importance? The close coupling among perfusion, blood temperature and aerobic metabolism in exercising and non-exercising extremities across different exercise modalities and activity levels and the tight association between limb vasodilatation and increases in plasma ATP suggest that both temperature...

  6. Regional cerebral blood perfusion SPECT imaging in brain ischemic injury due to cerebral hemorrhage

    International Nuclear Information System (INIS)

    Zhang Chunyin; Chen Yue; Li Zuoxiao; Tan Hua; Li Xiaohong

    2006-01-01

    Objective: To explore the clinical value of SPECT perfusion imaging in brain ischemic injury due to cerebral hemorrhage before and after treatment. Methods: Sixty cases of cerebral hemorrhage were randomly divided into nimodipine treated group and routine treated group. The volume of primary ischemic focus, changes of regional cerebral blood perfusion around hematoma and other cerebral areas were observed by SPECT imaging. Results: Volume of the primary focus was reduced apparently in both groups, but much more in nimodipine treated group (P<0.01). Also the regional cerebral blood flow in ischemic focus and remote areas increased much more in nimodipine treated group than routine treated group (P< 0.01). Conclusions: Brain SPECT imaging can sensitively reflect the regional cerebral blood flow before and after treatment. Thereby, it is useful for therapeutic monitoring. (authors)

  7. Ray-Based Approach to Skeletal Muscle Perfusion Measurement on Interventional X-ray Systems

    NARCIS (Netherlands)

    Giordano, M.; Vonken, E.J.; Bertram, M.; Mali, W.; Viergever, M.A.; Neukirchen, C.

    2012-01-01

    Purpose: Quantitative assessment of tissue perfusion by imaging methods could improve outcome control during treatment of peripheral vascular disease. Currently, revascularization treatments are assessedby planar angiography which only allows for qualitative inspection of blood flow in vessels. In

  8. Skin perfusion pressure measured by isotope washout in legs with arterial occlusive disease. Evaluation of different tracers, comparison to segmental systolic pressure, angiography and transcutaneous oxygen tension and variations during changes in systemic blood pressure

    DEFF Research Database (Denmark)

    Holstein, P; Trap-Jensen, J; Bagger, H

    1983-01-01

    ), 131I- -antipyrine (131I- -a.p.) was compared to Na(131I-) and 99Tcm-pertechnetate (99Tcm). The average SPP by 131I- -a.p. and by 131I- were approximately equal, 57.0 mmHg (range 18-93) compared to 56.3 mmHg (range 13-88) (P greater than 0.1). The average SPP by 99Tcm was just slightly higher, 60.3 mm...... that 99Tcm is as suitable as the 131I- -labelled tracers in estimating the SPP. The SPP is significantly correlated to skin blood flow, to systolic blood pressure, to tc pO2 and to angiographic findings. Correction of SPP for systemic blood pressure changes can be made in proportion with the measured...

  9. Compact dual-mode diffuse optical system for blood perfusion monitoring in a porcine model of microvascular tissue flaps

    Science.gov (United States)

    Lee, Seung Yup; Pakela, Julia M.; Helton, Michael C.; Vishwanath, Karthik; Chung, Yooree G.; Kolodziejski, Noah J.; Stapels, Christopher J.; McAdams, Daniel R.; Fernandez, Daniel E.; Christian, James F.; O'Reilly, Jameson; Farkas, Dana; Ward, Brent B.; Feinberg, Stephen E.; Mycek, Mary-Ann

    2017-12-01

    In reconstructive surgery, the ability to detect blood flow interruptions to grafted tissue represents a critical step in preventing postsurgical complications. We have developed and pilot tested a compact, fiber-based device that combines two complimentary modalities-diffuse correlation spectroscopy (DCS) and diffuse reflectance spectroscopy-to quantitatively monitor blood perfusion. We present a proof-of-concept study on an in vivo porcine model (n=8). With a controllable arterial blood flow supply, occlusion studies (n=4) were performed on surgically isolated free flaps while the device simultaneously monitored blood flow through the supplying artery as well as flap perfusion from three orientations: the distal side of the flap and two transdermal channels. Further studies featuring long-term monitoring, arterial failure simulations, and venous failure simulations were performed on flaps that had undergone an anastomosis procedure (n=4). Additionally, benchtop verification of the DCS system was performed on liquid flow phantoms. Data revealed relationships between diffuse optical measures and state of occlusion as well as the ability to detect arterial and venous compromise. The compact construction of the device, along with its noninvasive and quantitative nature, would make this technology suitable for clinical translation.

  10. Comparison of Cerebral Oxygen Saturation and Cerebral Perfusion Computed Tomography in Cerebral Blood Flow in Patients with Brain Injury.

    Science.gov (United States)

    Trofimov, Alexey O; Kalentiev, George; Voennov, Oleg; Grigoryeva, Vera

    2016-01-01

    The purpose of this study was to determine the relationship between cerebral tissue oxygen saturation and cerebral blood volume in patients with traumatic brain injury. Perfusion computed tomography of the brain was performed in 25 patients with traumatic brain injury together with simultaneous SctO2 level measurement using cerebral near-infrared oxymetry. The mean age of the injured persons was 34.5±15.6 years (range 15-65); 14 men, 11 women. The Injury Severity Score (ISS) values were 44.4±9.7 (range 25-81). The Glasgow Coma Score (GCS) mean value before the study was 10.6±2.1 (range 5-13). SctO2 ranged from 51 to 89%, mean 62±8.2%. Cerebral blood volume (CBV) values were 2.1±0.67 ml/100 g (min 1.1; max 4.3 ml/100 g). Cerebral blood flow (CBF) was 31.99±13.6 ml/100 g×min. Mean transit time (MTT) values were 5.7±4.5 s (min 2.8; max 34.3 s). The time to peak (TTP) was 22.2±3.1 s. A statistically significant correlation was found between SctO2 level and cerebral blood volume (CBV) level (R=0.9; pbrain tissue oxygenation and other parameters of brain perfusion.

  11. Error analysis of the double-integral method for calculating brain blood perfusion from inert gas clearance data

    International Nuclear Information System (INIS)

    Smith, G.T.; Stokely, E.M.; Lewis, M.H.; Devous, M.D. Sr.; Bonte, F.J.

    1984-01-01

    A single-photon dynamic computer-assisted tomograph (DSPECT) has been built and is currently being used to evaluate regional cerebral blood perfusion in patients and volunteers. A computer simulation of the system was created to analyze the effects of data collection, Poisson noise, attenuation compensation, and the reconstruction technique now employed in the DSPECT. Several methods of attenuation compensation were used to generate perfusion images from both ideal and noisy data. The results indicate that the mean perfusion is calculated to within 10.4% accuracy for all perfusion rates in a region of interest if attenuation correction is used. Without attenuation correction, perfusions are underestimated by as much as 27%. The three correctors tested have different effects on the calculated perfusion value, depending on the location of the region of interest in the picture. The algorithm introduces random noise that is proportional to both the random error in the input data and the perfusion rate. Air-curve delay errors result in inaccuracies in the final perfusion picture that are proportional to perfusion rate. Physiological values (0.8-1.5) of the partition coefficient cause overestimation of both gray (0-34%) and white (7-67%) matter perfusion values. Compton scatter and collimator effects were not addressed in this study

  12. Error analysis of the double-integral method for calculating brain blood perfusion from inert gas clearance data.

    Science.gov (United States)

    Smith, G T; Stokely, E M; Lewis, M H; Devous, M D; Bonte, F J

    1984-03-01

    A single-photon dynamic computer-assisted tomograph (DSPECT) has been built and is currently being used to evaluate regional cerebral blood perfusion in patients and volunteers. A computer simulation of the system was created to analyze the effects of data collection, Poisson noise, attenuation compensation, and the reconstruction technique now employed in the DSPECT. Several methods of attenuation compensation were used to generate perfusion images from both ideal and noisy data. The results indicate that the mean perfusion is calculated to within 10.4% accuracy for all perfusion rates in a region of interest if attenuation correction is used. Without attenuation correction, perfusions are underestimated by as much as 27%. The three correctors tested have different effects on the calculated perfusion value, depending on the location of the region of interest in the picture. The algorithm introduces random noise that is proportional to both the random error in the input data and the perfusion rate. Air-curve delay errors result in inaccuracies in the final perfusion picture that are proportional to perfusion rate. Physiological values (0.8-1.5) of the partition coefficient cause overestimation of both gray (0-34%) and white (7-67%) matter perfusion values. Compton scatter and collimator effects were not addressed in this study.

  13. Perfusion functional MRI reveals cerebral blood flow pattern under psychological stress

    Science.gov (United States)

    Wang, Jiongjiong; Rao, Hengyi; Wetmore, Gabriel S.; Furlan, Patricia M.; Korczykowski, Marc; Dinges, David F.; Detre, John A.

    2005-12-01

    Despite the prevalence of stress in everyday life and its impact on happiness, health, and cognition, little is known about the neural substrate of the experience of everyday stress in humans. We use a quantitative and noninvasive neuroimaging technique, arterial spin-labeling perfusion MRI, to measure cerebral blood flow (CBF) changes associated with mild to moderate stress induced by a mental arithmetic task with performance monitoring. Elicitation of stress was verified by self-report of stress and emotional state and measures of heart rate and salivary-cortisol level. The change in CBF induced by the stress task was positively correlated with subjective stress rating in the ventral right prefrontal cortex (RPFC) and left insula/putamen area. The ventral RPFC along with right insula/putamen and anterior cingulate showed sustained activation after task completion in subjects reporting a high stress level during arithmetic tasks. Additionally, variations of baseline CBF in the ventral RPFC and right orbitofrontal cortex were found to correlate with changes in salivary-cortisol level and heart rate caused by undergoing stress tasks. We further demonstrated that the observed right prefrontal activation could not be attributed to increased cognitive demand accompanying stress tasks and extended beyond neural pathways associated with negative emotions. Our results provide neuroimaging evidence that psychological stress induces negative emotion and vigilance and that the ventral RPFC plays a key role in the central stress response. anterior cingulate cortex | arterial spin labeling | right prefrontal cortex

  14. Relationships among ventilation-perfusion distribution, multiple inert gas methodology and metabolic blood-gas tensions.

    Science.gov (United States)

    Lee, A S; Patterson, R W; Kaufman, R D

    1987-12-01

    The retention equations upon which the Multiple Inert Gas Method is based are derived from basic principles using elementary algebra. It is shown that widely disparate distributions produce indistinguishable sets of retentions. The limits of resolution of perfused compartments in the VA/Q distribution obtainable by the use of the multiple inert gas method are explored mathematically, and determined to be at most shunt and two alveolar compartments ("tripartite" distribution). Every continuous distribution studied produced retentions indistinguishable from those of its unique "matching" tripartite distribution. When a distribution is minimally specified, it is unique. Any additional specification (increased resolution--more compartments) of the distribution results in the existence of an infinitude of possible distributions characterized by indistinguishable sets of retention values. No further increase in resolution results from the use of more tracers. When sets of retention values were extracted from published multiple inert gas method continuous distributions, and compared with the published "measured" retention sets, substantial differences were found. This illustrates the potential errors incurred in the practical, in vivo application of the multiple inert gas method. In preliminary studies, the tripartite distribution could be determined with at least comparable accuracy by blood-gas (oxygen, carbon dioxide) measurements.

  15. Reducing body fat with altitude hypoxia training in swimmers: role of blood perfusion to skeletal muscles.

    Science.gov (United States)

    Chia, Michael; Liao, Chin-An; Huang, Chih-Yang; Lee, Wen-Chih; Hou, Chien-Wen; Yu, Szu-Hsien; Harris, M Brennan; Hsu, Tung-Shiung; Lee, Shin-Da; Kuo, Chia-Hua

    2013-02-28

    Swimmers tend to have greater body fat than athletes from other sports. The purpose of the study was to examine changes in body composition after altitude hypoxia exposure and the role of blood distribution to the skeletal muscle in swimmers. With a constant training volume of 12.3 km/day, young male swimmers (N = 10, 14.8 ± 0.5 years) moved from sea-level to a higher altitude of 2,300 meters. Body composition was measured before and after translocation to altitude using dual-energy X-ray absorptiometry (DXA) along with 8 control male subjects who resided at sea level for the same period of time. To determine the effects of hypoxia on muscle blood perfusion, total hemoglobin concentration (THC) was traced by near-infrared spectroscopy (NIRS) in the triceps and quadriceps muscles under glucose-ingested and insulin-secreted conditions during hypoxia exposure (16% O2) after training. While no change in body composition was found in the control group, subjects who trained at altitude had unequivocally decreased fat mass (-1.7 ± 0.3 kg, -11.4%) with increased lean mass (+0.8 ± 0.2 kg, +1.5%). Arterial oxygen saturation significantly decreased with increased plasma lactate during hypoxia recovery mimicking 2,300 meters at altitude (~93% versus ~97%). Intriguingly, hypoxia resulted in elevated muscle THC, and sympathetic nervous activities occurred in parallel with greater-percent oxygen saturation in both muscle groups. In conclusion, the present study provides evidence that increased blood distribution to the skeletal muscle under postprandial condition may contribute to the reciprocally increased muscle mass and decreased body mass after a 3-week altitude exposure in swimmers.

  16. Evaluation of ocular acupuncture on cerebral infarction with cerebral blood flow perfusion imaging

    International Nuclear Information System (INIS)

    Li Yuge; Gao Qinyi; Wang Shuang; Zhao Yong

    2008-01-01

    To evaluate the immediate effect of ocular acupuncture on patients, an method of SPECT image of cerebral blood flow daily stress test was established. 10 patients diagnosed as cerebral infarction by CT or MRI were tested. They all received 99 Tc m -ECD SPECT imaging at twice before and after ocular acupuncture. By means of image subtraction technique and semi-quantitative method of regional interesting area, the change of regional cerebral blood flow was observed between the two images. Under restful state perfusion of cerebral blood flow in 18 foci was low at the frontal lobe, the cerebellum, the basal ganglia and temporal lobe. After ocular acupuncture, the perfusions were obviously increased in 16 foci among them and the reactivity of the frontal lobe and the cerebellum to ocular acupuncture was higher, the average improvement rate of which was 55.15% and 53.06% respectively, lower in the basal ganglia and temporal lobe, the average improvement rate was 31.79% and 36.67% respectively. 99 Tc m -ECD SPECT cerebral perfusion image has some significant clinic value for evaluating the effect of ocular acupuncture to treating cerebral infarction. (authors)

  17. Influence of red blood cell aggregation on perfusion of an artificial microvascular network.

    Science.gov (United States)

    Reinhart, Walter H; Piety, Nathaniel Z; Shevkoplyas, Sergey S

    2017-07-01

    RBCs suspended in plasma form multicellular aggregates under low-flow conditions, increasing apparent blood viscosity at low shear rates. It has previously been unclear, however, if RBC aggregation affects microvascular perfusion. Here, we analyzed the impact of RBC aggregation on perfusion and 'capillary' hematocrit in an AMVN at driving pressures ranging from 5 to 60 cm H 2 O to determine if aggregation could improve tissue oxygenation. RBCs were suspended at 30% hematocrit in either 46.5 g/L dextran 40 (D40, non-aggregating medium) or 35 g/L dextran 70 (D70, aggregating medium) solutions with equal viscosity. Aggregation was readily observed in the AMVN for RBCs suspended in D70 at driving pressures ≤40 cm H 2 O. The AMVN perfusion rate was the same for RBCs suspended in aggregating and non-aggregating medium, at both 'venular' and 'capillary' level. Estimated 'capillary' hematocrit was higher for D70 suspensions than for D40 suspensions at intermediate driving pressures (5-40 cm H 2 O). We conclude that although RBC aggregation did not affect the AMVN perfusion rate independently of the driving pressure, a higher hematocrit in the 'capillaries' of the network for D70 suspensions suggested a better oxygen transport capacity in the presence of RBC aggregation. © 2016 John Wiley & Sons Ltd.

  18. Effects of shear forces and pressure on blood vessel function and metabolism in a perfusion bioreactor.

    Science.gov (United States)

    Hoenicka, Markus; Wiedemann, Ludwig; Puehler, Thomas; Hirt, Stephan; Birnbaum, Dietrich E; Schmid, Christof

    2010-12-01

    Bovine saphenous veins (BSV) were incubated in a perfusion bioreactor to study vessel wall metabolism and wall structure under tissue engineering conditions. Group 1 vessels were perfused for 4 or 8 days. The viscosity of the medium was increased to that of blood in group 2. Group 3 vessels were additionally strained with luminal pressure. Groups 1-d through 3-d were similar except that BSV were endothelium-denuded before perfusion. Groups 1-a through 3-a used native vessels at elevated flow rates. Group 3 vessels responded significantly better to noradrenaline on day 4, whereas denuded vessels showed attenuated responses (p vessels. pO₂ gradients across the vessels were independent of time and significantly higher in group 2 (p vessels of groups 3, 1-d, and 3-d which released more lactate than glucose could supply (p vessels as well as all vessels perfused with elevated flow rates showed a loss of endothelial cells after 4 days, whereas group 2 and 3 vessels retained most of the endothelium. These data suggest that vessel metabolism was not limited by oxygen supply. Shear forces did not affect glucose metabolism but increased oxygen consumption and endothelial cell survival. Luminal pressure caused the utilization of energy sources other than glucose, as long as the endothelium was intact. Therefore, vessel metabolism needs to be monitored during tissue engineering procedures which challenge the constructs with mechanical stimuli.

  19. Validation of measurements of ventilation-to-perfusion ratio inequality in the lung from expired gas

    Science.gov (United States)

    Prisk, G. Kim; Guy, Harold J B.; West, John B.; Reed, James W.

    2003-01-01

    The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (Va/Q) inequality in the lung. To further validate this estimate, we examined three measures of Va/Q inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions and after exposure to aerosolized methacholine. These measurements were then compared with arterial blood gases and with measurements of Va/Q inhomogeneity obtained using the multiple inert gas elimination technique. The slope of the instantaneous respiratory exchange ratio (R slope) vs. expired volume was poorly correlated with independent measures, probably because of the curvilinear nature of the relationship due to continuing gas exchange. When R was converted to the intrabreath Va/Q (iV/Q), the best index was the slope of iV/Q vs. volume over phase III (iV/Q slope). This was strongly correlated with independent measures, especially those relating to inhomogeneity of perfusion. The correlations for iV/Q slope and R slope considerably improved when only the first half of phase III was considered. We conclude that a useful noninvasive measurement of Va/Q inhomogeneity can be derived from the intrabreath respiratory exchange ratio.

  20. Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain

    International Nuclear Information System (INIS)

    Sedlacik, Jan; Fiehler, Jens; Reitz, Matthias; Schmidt, Nils O.; Bolar, Divya S.; Adalsteinsson, Elfar

    2015-01-01

    The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml.kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s and -1] = 20.7/20.4/20.1, R2*[s and -1] = 31.6/29.6/25.9, R2'[s and 1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml.min and -1.100g and -1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood oxygenation level. We found good

  1. Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacik, Jan; Fiehler, Jens [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neuroradiology; Reitz, Matthias; Schmidt, Nils O. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neurosurgery; Bolar, Divya S. [Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA (United States). Radiology; Adalsteinsson, Elfar [Massachusetts Institute of Technology, Cambridge, MA (United States). Electrical Engineering and Computer Science

    2015-05-01

    The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml.kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s {sup and} -1] = 20.7/20.4/20.1, R2*[s {sup and} -1] = 31.6/29.6/25.9, R2'[s {sup and} 1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml.min {sup and} -1.100g {sup and} -1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood

  2. Scintigraphic study of blood perfusion of the pulmonary artery in pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Certain, D.A.; Brolio, R.; Salomon, G.C.; Carvalho, N.; Barbosa, Z.L.M.

    1972-01-01

    Blood perfusion in the pulmonary artery is studied by pulmonary scintigraphy with macroaggregated albumin 131 I, in 74 cases of pulmonary tuberculosis. Results shown by scintigraphy are compared to those observed in roentgenography and also correlated with the extension and degree of the lesions, and with the presence of associated tuberculosis, considered capable of changing the scintigraphic picture. The reduction of blood flow in the pulmonary artery are observed in cases of infiltrative, fibrotic of caseous lesions, as well as in cases of minor lesions [pt

  3. Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Ogami, M; Kulkarni, R; Wang, H; Reif, R; Wang, R K [University of Washington, Department of Bioengineering, Seattle, Washington 98195 (United States)

    2014-08-31

    We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing. (laser biophotonics)

  4. Non-invasive estimation of hepatic blood perfusion from H215O PET images using tissue-derived arterial and portal input functions

    International Nuclear Information System (INIS)

    Kudomi, N.; Slimani, L.; Jaervisalo, M.J.; Lautamaeki, R.; Naum, G.A.; Knuuti, J.; Kiss, J.; Savunen, T.; Iida, H.; Nuutila, P.; Iozzo, P.

    2008-01-01

    The liver is perfused through the portal vein and the hepatic artery. When its perfusion is assessed using positron emission tomography (PET) and 15 O-labeled water (H 2 15 O), calculations require a dual blood input function (DIF), i.e., arterial and portal blood activity curves. The former can be generally obtained invasively, but blood withdrawal from the portal vein is not feasible in humans. The aim of the present study was to develop a new technique to estimate quantitative liver perfusion from H 2 15 O PET images with a completely non-invasive approach. We studied normal pigs (n=14) in which arterial and portal blood tracer concentrations and Doppler ultrasonography flow rates were determined invasively to serve as reference measurements. Our technique consisted of using model DIF to create tissue model function and the latter method to simultaneously fit multiple liver time-activity curves from images. The parameters obtained reproduced the DIF. Simulation studies were performed to examine the magnitude of potential biases in the flow values and to optimize the extraction of multiple tissue curves from the image. The simulation showed that the error associated with assumed parameters was 2 15 O PET imaging. This suggests the possibility to enable completely non-invasive technique to assess liver perfusion in patho-physiological studies. (orig.)

  5. Increased brainstem perfusion, but no blood-brain barrier disruption, during attacks of migraine with aura.

    Science.gov (United States)

    Hougaard, Anders; Amin, Faisal M; Christensen, Casper E; Younis, Samaira; Wolfram, Frauke; Cramer, Stig P; Larsson, Henrik B W; Ashina, Messoud

    2017-06-01

    See Moskowitz (doi:10.1093/brain/awx099) for a scientific commentary on this article.The migraine aura is characterized by transient focal cortical disturbances causing dramatic neurological symptoms that are usually followed by migraine headache. It is currently not understood how the aura symptoms are related to the headache phase of migraine. Animal studies suggest that cortical spreading depression, the likely mechanism of migraine aura, causes disruption of the blood-brain barrier and noxious stimulation of trigeminal afferents leading to activation of brainstem nuclei and triggering of migraine headache. We used the sensitive and validated technique of dynamic contrast-enhanced high-field magnetic resonance imaging to simultaneously investigate blood-brain barrier permeability and tissue perfusion in the brainstem (at the level of the lower pons), visual cortex, and brain areas of the anterior, middle and posterior circulation during spontaneous attacks of migraine with aura. Patients reported to our institution to undergo magnetic resonance imaging during the headache phase after presenting with typical visual aura. Nineteen patients were scanned during attacks and on an attack-free day. The mean time from attack onset to scanning was 7.6 h. We found increased brainstem perfusion bilaterally during migraine with aura attacks. Perfusion also increased in the visual cortex and posterior white matter following migraine aura. We found no increase in blood-brain barrier permeability in any of the investigated regions. There was no correlation between blood-brain barrier permeability, brain perfusion, and time from symptom onset to examination or pain intensity. Our findings demonstrate hyperperfusion in brainstem during the headache phase of migraine with aura, while the blood-brain barrier remains intact during attacks of migraine with aura. These data thus contradict the preclinical hypothesis of cortical spreading depression-induced blood-brain barrier

  6. Measurement of Choroidal Perfusion and Thickness Following Systemic Sildenafil (Viagra®)

    Science.gov (United States)

    Kim, David Y.; Silverman, Ronald H.; Chan, R.V. Paul; Khanifar, Aziz A.; Rondeau, Mark; Lloyd, Harriet; Schlegel, Peter; Coleman, D. Jackson

    2011-01-01

    Objective To demonstrate anatomic and physiologic changes in the human choroid following systemic sildenafil citrate (ViagraR) using enhanced depth imaging spectral domain-optical coherence tomography (EDI-OCT) and swept-scan high frequency digital ultrasound. Methods Seven healthy male subjects (mean age 32.7 years) were evaluated at baseline and two hours after ingesting 50 mg of sildenafil. Swept-scan high frequency digital ultrasound and EDI-OCT were utilized to measure choroidal perfusion and thickness, respectively. Results were read by masked observers. The Wilcoxon signed-rank test and t-test were used to analyze differences in choroidal flow and thickness at baseline and two hours after ingestion of sildenafil. Results Two hours following sildenafil, increased choroidal perfusion was observed in 11 of 12 eyes measured by swept-scan high frequency digital ultrasound. The mean increase was 3.46 (±2.00) times baseline with a range of 0.47 to 7.80 times baseline (p=0.004). Increased choroidal thickness was observed in 12 of 12 eyes measured with EDI-OCT. The average choroidal thickness increased by 11.6% temporal to the fovea, 9.3% nasal to the fovea, and 10.7% underneath the fovea (p<0.001 for all values). Conclusions Choroidal perfusion and thickness both increase in response to systemic sildenafil. These changes could secondarily affect retinal function, explain previously reported clinical symptoms, and potentially be a useful adjunct for treatment of ocular diseases that would benefit from increased choroidal blood flow. PMID:22974308

  7. Macro- and microelements in the rat liver, kidneys, and brain tissues; sex differences and effect of blood removal by perfusion in vivo.

    Science.gov (United States)

    Orct, Tatjana; Jurasović, Jasna; Micek, Vedran; Karaica, Dean; Sabolić, Ivan

    2017-03-01

    Concentrations of macro- and microelements in animal organs indicate the animal health status and represent reference data for animal experiments. Their levels in blood and tissues could be different between sexes, and could be different with and without blood in tissues. To test these hypotheses, in adult female and male rats the concentrations of various elements were measured in whole blood, blood plasma, and tissues from blood-containing (nonperfused) and blood-free liver, kidneys, and brain (perfused in vivo with an elements-free buffer). In these samples, 6 macroelements (Na, Mg, P, S, K, Ca) and 14 microelements (Fe, Mn, Co, Cu, Zn, Se, I, As, Cd, Hg, Pb, Li, B, Sr) were determined by inductively coupled plasma mass spectrometry following nitric acid digestion. In blood and plasma, female- or male-dominant sex differences were observed for 6 and 5 elements, respectively. In nonperfused organs, sex differences were observed for 3 (liver, brain) or 9 (kidneys) elements, whereas in perfused organs, similar differences were detected for 9 elements in the liver, 5 in the kidneys, and none in the brain. In females, perfused organs had significantly lower concentrations of 4, 5, and 2, and higher concentrations of 10, 4, and 7 elements, respectively, in the liver, kidneys, and brain. In males, perfusion caused lower concentrations of 4, 7, and 2, and higher concentrations of 1, 1, and 7 elements, respectively, in the liver, kidneys, and brain. Therefore, the residual blood in organs can significantly influence tissue concentrations of various elements and their sex-dependency. Copyright © 2017 Elsevier GmbH. All rights reserved.

  8. 3D pulmonary perfusion MRI and MR angiography of pulmonary embolism in pigs after a single injection of a blood pool MR contrast agent

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Christian; Ley, Sebastian; Puderbach, Michael; Plathow, Christian; Kauczor, Hans-Ulrich [Department of Radiology, Innovative Cancer Diagnostic and Therapy, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg (Germany); Bock, Michael [Department of Medical Physics in Radiology, Innovative Cancer Diagnostic and Therapy, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg (Germany)

    2004-07-01

    The purpose of this study was to assess the feasibility of contrast-enhanced 3D perfusion MRI and MR angiography (MRA) of pulmonary embolism (PE) in pigs using a single injection of the blood pool contrast Gadomer. PE was induced in five domestic pigs by injection of autologous blood thrombi. Contrast-enhanced first-pass 3D perfusion MRI (TE/TR/FA: 1.0 ms/2.2 ms/40 ; voxel size: 1.3 x 2.5 x 4.0 mm{sup 3}; TA: 1.8 s per data set) and high-resolution 3D MRA (TE/TR/FA: 1.4 ms/3.4 ms/40 ; voxel size: 0.8 x 1.0 x 1.6 mm{sup 3}) was performed during and after a single injection of 0.1 mmol/kg body weight of Gadomer. Image data were compared to pre-embolism Gd-DTPA-enhanced MRI and post-embolism thin-section multislice CT (n=2). SNR measurements were performed in the pulmonary arteries and lung. One animal died after induction of PE. In all other animals, perfusion MRI and MRA could be acquired after a single injection of Gadomer. At perfusion MRI, PE could be detected by typical wedge-shaped perfusion defects. While the visualization of central PE at MRA correlated well with the CT, peripheral PE were only visualized by CT. Gadomer achieved a higher peak SNR of the lungs compared to Gd-DTPA (21{+-}8 vs. 13{+-}3). Contrast-enhanced 3D perfusion MRI and MRA of PE can be combined using a single injection of the blood pool contrast agent Gadomer. (orig.)

  9. Optoacoustic measurements of human placenta and umbilical blood oxygenation

    Science.gov (United States)

    Nanovskaya, T. N.; Petrov, I. Y.; Petrov, Y.; Patrikeeva, S. L.; Ahmed, M. S.; Hankins, G. D. V.; Prough, D. S.; Esenaliev, R. O.

    2016-03-01

    Adequate oxygenation is essential for normal embryogenesis and fetal growth. Perturbations in the intrauterine oxidative environment during pregnancy are associated with several pathophysiological disorders such as pregnancy loss, preeclampsia, and intrauterine growth restriction. We proposed to use optoacoustic technology for monitoring placental and fetal umbilical blood oxygenation. In this work, we studied optoacoustic monitoring of oxygenation in placenta and umbilical cord blood ex vivo using technique of placenta perfusion. We used a medical grade, nearinfrared, tunable, optoacoustic system developed and built for oxygenation monitoring in blood vessels and in tissues. First, we calibrated the system for cord blood oxygenation measurements by using a CO-Oximeter (gold standard). Then we performed validation in cord blood circulating through the catheters localized on the fetal side of an isolated placental lobule. Finally, the oxygenation measurements were performed in the perfused placental tissue. To increase or decrease blood oxygenation, we used infusion of a gas mixture of 95% O2 + 5% CO2 and 95% N2 + 5% CO2, respectively. In placental tissue, up to four cycles of changes in oxygenation were performed. The optoacoustically measured oxygenation in circulating cord blood and in placental lobule closely correlated with the actual oxygenation data measured by CO-Oximeter. We plan to further test the placental and cord blood oxygenation monitoring with optoacoustics in animal and clinical studies.

  10. Can the green laser doppler measure skin-nutritive perfusion in patients with peripheral vascular disease?

    NARCIS (Netherlands)

    Ubbink, D. T.; Tulevski, I. I.; Jacobs, M. J.

    2000-01-01

    The recently developed green laser (GL; wavelength 543 nm) is thought to measure perfusion derived from a more superficial skin layer than does the standard near-infrared laser (RL; wavelength 780 nm). These lasers were used to investigate the disturbances in the different layers of skin perfusion

  11. Investigation of Hepatic Blood Perfusion by Laser Speckle Imaging and Changes of Hepatic Vasoactive Substances in Mice after Electroacupuncture

    Directory of Open Access Journals (Sweden)

    Xiao-jing Song

    2014-01-01

    Full Text Available The study was conducted to observe the effect of electroacupuncture (EA on hepatic blood perfusion (HBP and vascular regulation. We investigated 60 male anesthetized mice under the following 3 conditions: without EA stimulation (control group; EA stimulation at Zusanli (ST36 group; EA stimulation at nonacupoint (NA group during 30 min. The HBP was measured using the laser speckle perfusion imaging (LSPI. The level of nitric oxide (NO, endothelin-1 (ET-1, and noradrenaline (NE in liver tissue was detected by biochemical methods. Results were as follows. At each time point, HBP increase in ST36 group was higher than that in the NA group in anesthetized mice. HBP gradually decreased during 30 min in control group. The level of NO in ST36 group was higher than that in NA group. The level of both ET-1 and NE was the highest in control group, followed by NA group and ST36 group. It is concluded that EA at ST36 could increase HBP possibly by increasing the blood flow velocity (BFV, changing vascular activity, increasing the level of NO, and inhibiting the level of ET-1 in liver tissue.

  12. Comparison of Acupuncture Effect on Blood Perfusion between Needling Nonacupoint on Meridian and Needling Nonacupoint off Meridian

    Directory of Open Access Journals (Sweden)

    Wei-Bo Zhang

    2013-01-01

    Full Text Available To verify the ancient theory of rather missing the acupoint than missing the meridian, acupuncture at nonacupoint on meridian and acupuncture at nonacupoint off meridian were performed, respectively. The blood perfusion (BP on the calf around bladder meridian area was measured with a laser Doppler perfusion imager before, during, and after acupuncture. The whole scanning field was divided into seven subareas, and mean BP on each area was calculated. The ratio of mean BP between a subarea and a reference subarea was gotten, and then the change rate was calculated as ratio change rate (RCR. The results showed that RCR on bladder meridian area and around Chengshan (BL57 during or after acupuncture at nonacupoint on meridian was significantly higher than that at nonacupoint off meridian, which supports the ancient theory. Such differences may be attributable to some factors that can facilitate the signals transmission and produce a better acupuncture effect, such as richer nerve terminals, blood vessels, and mast cells which can produce stronger signals on the acupoints and the low hydraulic resistance channel along meridians which plays a role of signal transmitting channel to get a better effect of acupuncture.

  13. Non-invasive estimation of hepatic blood perfusion from H{sub 2} {sup 15}O PET images using tissue-derived arterial and portal input functions

    Energy Technology Data Exchange (ETDEWEB)

    Kudomi, N.; Slimani, L.; Jaervisalo, M.J.; Lautamaeki, R.; Naum, G.A.; Knuuti, J. [University of Turku, Turku PET Centre (Finland); Kiss, J.; Savunen, T. [University of Turku, Department on Surgery, Turku (Finland); Iida, H. [National Cardiovascular Center-Research Institute, Department of Investigative Radiology, Advanced Medical-Engineering Center, Suita, Osaka (Japan); Nuutila, P. [University of Turku, Turku PET Centre (Finland); University of Turku, Department of Medicine, Turku (Finland); Iozzo, P. [University of Turku, Turku PET Centre (Finland); National Research Council, Institute of Clinical Physiology, Pisa (Italy)

    2008-10-15

    The liver is perfused through the portal vein and the hepatic artery. When its perfusion is assessed using positron emission tomography (PET) and {sup 15}O-labeled water (H{sub 2}{sup 15}O), calculations require a dual blood input function (DIF), i.e., arterial and portal blood activity curves. The former can be generally obtained invasively, but blood withdrawal from the portal vein is not feasible in humans. The aim of the present study was to develop a new technique to estimate quantitative liver perfusion from H{sub 2}{sup 15}O PET images with a completely non-invasive approach. We studied normal pigs (n=14) in which arterial and portal blood tracer concentrations and Doppler ultrasonography flow rates were determined invasively to serve as reference measurements. Our technique consisted of using model DIF to create tissue model function and the latter method to simultaneously fit multiple liver time-activity curves from images. The parameters obtained reproduced the DIF. Simulation studies were performed to examine the magnitude of potential biases in the flow values and to optimize the extraction of multiple tissue curves from the image. The simulation showed that the error associated with assumed parameters was <10%, and the optimal number of tissue curves was between 10 and 20. The estimated DIFs were well reproduced against the measured ones. In addition, the calculated liver perfusion values were not different between the methods and showed a tight correlation (r=0.90). In conclusion, our results demonstrate that DIF can be estimated directly from tissue curves obtained through H{sub 2}{sup 15}O PET imaging. This suggests the possibility to enable completely non-invasive technique to assess liver perfusion in patho-physiological studies. (orig.)

  14. Laser doppler perfusion imaging

    International Nuclear Information System (INIS)

    Waardell, K.

    1992-01-01

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

  15. Effect of radial artery harvest on collateral forearm blood flow and digital perfusion.

    Science.gov (United States)

    Brodman, Richard F; Hirsh, Laurie E; Frame, Rosemary

    2002-03-01

    Changes describing digital and forearm circulation after radial artery harvest have been reported infrequently. This prospective study examined digital perfusion and forearm collateral circulation preoperatively and postoperatively in patients who underwent coronary artery bypass grafting with radial artery free grafts. Noninvasive evaluation was conducted with digital photoelectric plethysmography and color flow and pulsed Doppler studies. Thumb perfusion index decreased from 1.25 to 0.84 (30%, P <.001) in the unoperated extremities and from 1.23 to 0.80 (36%) in the operated extremities (P <.001). Doppler studies in extremities after radial artery harvest demonstrated an increase in ulnar artery diameter from 3.87 to 4.66 mm (15.7%, P <.001) and a rise in ulnar blood flow velocity from 38.96 to 48.46 cm/s (17.4%) preoperatively to 8 weeks postoperatively (P <.001). No hand ischemia was noted. Our study identified a mild reduction in digital perfusion and an increase in ulnar artery flow velocity and diameter with no clinical sequelae or compromise in hand function after radial artery harvest in properly selected patients.

  16. Measurement of Outflow Facility Using iPerfusion.

    Directory of Open Access Journals (Sweden)

    Joseph M Sherwood

    Full Text Available Elevated intraocular pressure (IOP is the predominant risk factor for glaucoma, and reducing IOP is the only successful strategy to prevent further glaucomatous vision loss. IOP is determined by the balance between the rates of aqueous humour secretion and outflow, and a pathological reduction in the hydraulic conductance of outflow, known as outflow facility, is responsible for IOP elevation in glaucoma. Mouse models are often used to investigate the mechanisms controlling outflow facility, but the diminutive size of the mouse eye makes measurement of outflow technically challenging. In this study, we present a new approach to measure and analyse outflow facility using iPerfusion™, which incorporates an actuated pressure reservoir, thermal flow sensor, differential pressure measurement and an automated computerised interface. In enucleated eyes from C57BL/6J mice, the flow-pressure relationship is highly non-linear and is well represented by an empirical power law model that describes the pressure dependence of outflow facility. At zero pressure, the measured flow is indistinguishable from zero, confirming the absence of any significant pressure independent flow in enucleated eyes. Comparison with the commonly used 2-parameter linear outflow model reveals that inappropriate application of a linear fit to a non-linear flow-pressure relationship introduces considerable errors in the estimation of outflow facility and leads to the false impression of pressure-independent outflow. Data from a population of enucleated eyes from C57BL/6J mice show that outflow facility is best described by a lognormal distribution, with 6-fold variability between individuals, but with relatively tight correlation of facility between fellow eyes. iPerfusion represents a platform technology to accurately and robustly characterise the flow-pressure relationship in enucleated mouse eyes for the purpose of glaucoma research and with minor modifications, may be applied

  17. Semi-quantitative myocardial perfusion measured by computed tomography in patients with refractory angina

    DEFF Research Database (Denmark)

    Qayyum, Abbas Ali; Kühl, Jørgen Tobias; Kjaer, Andreas

    2017-01-01

    INTRODUCTION: Computed tomography (CT) is a novel method for assessment of myocardial perfusion and has not yet been compared to rubidium-82 positron emission tomography (PET). We aimed to compare CT measured semi-quantitative myocardial perfusion with absolute quantified myocardial perfusion using...... scanner and CT/PET 64-slice scanner. CT measured myocardial attenuation density (AD) and perfusion index (PI) were correlated to absolute PET myocardial perfusion values. RESULTS: Rest AD, rest and stress PI did not correlate to PET findings (r = 0·412, P = 0·113; r = 0·300, P = 0·259; and r = 0·508, P...... PET and to detect stenotic territories in patients with severe coronary artery disease. MATERIALS AND METHODS: Eighteen patients with stenosis narrowing coronary arteries ≥70% demonstrated on invasive coronary angiography underwent rest and adenosine stress imaging obtained by 320-multidetector CT...

  18. Polarographic measurement of ascorbate washout in isolated perfused rabbit hearts

    International Nuclear Information System (INIS)

    Arts, T.; Kuikka, J.T.; Reneman, R.S.; Bassingthwaighte, J.B.

    1985-01-01

    To study the myocardial washout of ascorbate, the applicability of polarographic detection of ascorbate ions by a platinum electrode (sensitive area 0.03 mm2) was investigated, in both a calibration setup (sampling flow along the electrode: 100 microliter X s-1) and isolated, retrogradely perfused rabbit hearts. In the calibration setup at pH 7.4, the sensitivity of the electrode was 70 microA/mol. This sensitivity increased moderately with increasing pH (13%/unit pH) and increasing sampling flow rate (14% at an increase from 100 to 150 microliter X s-1). In the isolated hearts, ascorbate infused into the aorta was detected in a right ventricular drain by the electrode as well as by the use of 14 C-labeled ascorbate. Both recorded time courses were similar except for a scaling factor dependent on flow velocity. During continuous infusion the arteriovenous difference of ascorbate was 2 +/- 2% (SD), indicating a relatively low consumption of ascorbate by the isolated heart. The authors conclude that polarographic measurement of ascorbate in the coronary effluent of an isolated rabbit heart can be performed on-line and relatively easily

  19. MRI of myocardial perfusion.

    Science.gov (United States)

    Jerosch-Herold, Michael; Muehling, Olaf; Wilke, Norbert

    2006-02-01

    An overwhelming number of myocardial perfusion studies are done by nuclear isotope imaging. Magnetic resonance imaging during the first pass of an injected, contrast bolus has some significant advantages for detection of blood flow deficits, namely higher spatial resolution, absence of ionizing radiation, and speed of the test. Previous clinical studies have demonstrated that excellent sensitivity and specificity can be achieved with MR myocardial perfusion imaging for detecting coronary artery disease, and assessment of patients with acute chest pain. Furthermore, an absolute quantification of myocardial blood flow is feasible, as was demonstrated by comparison of MR perfusion imaging, to measurements with isotope labeled microspheres in experimental models. An integrated assessment of perfusion, function, and viability, is thus feasible by MRI to answer important clinical challenges such as the identification of stunned or hibernating, but viable myocardium.

  20. Insulin resistance is associated with lower arterial blood flow and reduced cortical perfusion in cognitively asymptomatic middle-aged adults.

    Science.gov (United States)

    Hoscheidt, Siobhan M; Kellawan, J Mikhail; Berman, Sara E; Rivera-Rivera, Leonardo A; Krause, Rachel A; Oh, Jennifer M; Beeri, Michal S; Rowley, Howard A; Wieben, Oliver; Carlsson, Cynthia M; Asthana, Sanjay; Johnson, Sterling C; Schrage, William G; Bendlin, Barbara B

    2017-06-01

    Insulin resistance (IR) is associated with poor cerebrovascular health and increased risk for dementia. Little is known about the unique effect of IR on both micro- and macrovascular flow particularly in midlife when interventions against dementia may be most effective. We examined the effect of IR as indexed by the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) on cerebral blood flow in macro- and microvessels utilizing magnetic resonance imaging (MRI) among cognitively asymptomatic middle-aged individuals. We hypothesized that higher HOMA-IR would be associated with reduced flow in macrovessels and lower cortical perfusion. One hundred and twenty cognitively asymptomatic middle-aged adults (57 ± 5 yrs) underwent fasting blood draw, phase contrast-vastly undersampled isotropic projection reconstruction (PC VIPR) MRI, and arterial spin labeling (ASL) perfusion. Higher HOMA-IR was associated with lower arterial blood flow, particularly within the internal carotid arteries (ICAs), and lower cerebral perfusion in several brain regions including frontal and temporal lobe regions. Higher blood flow in bilateral ICAs predicted greater cortical perfusion in individuals with lower HOMA-IR, a relationship not observed among those with higher HOMA-IR. Findings provide novel evidence for an uncoupling of macrovascular blood flow and microvascular perfusion among individuals with higher IR in midlife.

  1. A pilot study of regional perfusion and oxygenation in calf muscles of individuals with diabetes with a noninvasive measure.

    Science.gov (United States)

    Zheng, Jie; Hasting, Mary K; Zhang, Xiaodong; Coggan, Andrew; An, Hongyu; Snozek, Darrah; Curci, John; Mueller, Michael J

    2014-02-01

    To assess alterations in the regional perfusion and oxygenation of the calf muscles in individuals with diabetes. Age-matched individuals with (n = 5) and without diabetes (n = 6) were investigated. Skeletal muscle perfusion, oxygen extraction fraction, and oxygen consumption rate were measured by newly developed noncontrast magnetic resonance imaging (MRI) techniques. The subjects lay supine on the MRI table with their foot firmly strapped to a custom-built isometric exercise device. The measurements were performed at rest and during an isometric plantar flexion muscle contraction. Individuals without diabetes had up to a 10-fold increase in muscle perfusion, 25% elevation in muscle oxygen extraction fraction, and a 12-fold increase in oxygen consumption rate in the calf during the plantar flexion isometric contraction. In patients with diabetes, the increases in these parameters were only up to sixfold, 2%, and sixfold, respectively. Exercise oxygen consumption rate was inversely associated with blood HbA1c levels (r(2) = .91). This is the first study to quantify regional skeletal muscle oxygenation in patients with diabetes using noncontrast MRI and warrants additional study. Attenuation of perfusion and oxygenation during exercise may have implications for understanding diabetic complications in the lower extremities. Copyright © 2014 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  2. Methodological NMR imaging developments to measure cerebral perfusion

    International Nuclear Information System (INIS)

    Pannetier, N.

    2010-12-01

    This work focuses on acquisition techniques and physiological models that allow characterization of cerebral perfusion by MRI. The arterial input function (AIF), on which many models are based, is measured by a technique of optical imaging at the carotid artery in rats. The reproducibility and repeatability of the AIF are discussed and a model function is proposed. Then we compare two techniques for measuring the vessel size index (VSI) in rats bearing a glioma. The reference technique, using a USPIO contrast agent (CA), faces the dynamic approach that estimates this parameter during the passage of a bolus of Gd. This last technique has the advantage of being used clinically. The results obtained at 4.7 T by both approaches are similar and use of VSI in clinical protocols is strongly encouraged at high field. The mechanisms involved (R1 and R2* relaxivities) were then studied using a multi gradient -echoes approach. A multi-echoes spiral sequence is developed and a method that allows the refocusing between each echo is presented. This sequence is used to characterize the impact of R1 effects during the passage of two successive injections of Gd. Finally, we developed a tool for simulating the NMR signal on a 2D geometry taking into account the permeability of the BBB and the CA diffusion in the interstitial space. At short TE, the effect of diffusion on the signal is negligible. In contrast, the effects of diffusion and permeability may be separated at long echo time. Finally we show that during the extravasation of the CA, the local magnetic field homogenization due to the decrease of the magnetic susceptibility difference at vascular interfaces is quickly balanced by the perturbations induced by the increase of the magnetic susceptibility difference at the cellular interfaces in the extravascular compartment. (author)

  3. Radiation exposure to surgical staff during hyperthermic isolated limb perfusion with 99m Technetium labeled red blood cells

    DEFF Research Database (Denmark)

    Kristoffersen, Ulrik Sloth; Straalman, Kristina; Schmidt, Grethe

    2009-01-01

    HILP with (99m)Technetium labeled red blood cells. MATERIALS AND METHODS: Thirteen patients had HILP performed in 11 lower limbs and two upper limbs at our inpatient clinic between October 2006 and February 2007. The surgeon and nurse had thermoluminescence dosimetry (TLD) chips attached to the finger...... to the limb circuit. This has made HILP safe for the patient. However, the radiation exposure to the surgical staff has never been measured and could be a limiting factor for the use of HILP. The purpose of the present study was to measure and evaluate the radiation exposure to the surgical staff performing...... pulp and to the ring area of the left fourth finger, as well as an electronic dosimeter attached to the anterior lining of the trousers. The anesthesiologist and perfusion technologist also carried electronic dosimeters. RESULTS: The surgeon had the highest radioactive exposure with an average dose per...

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

    Science.gov (United States)

    Djuric-Stefanovic, A; Saranovic, Dj; Sobic-Saranovic, D; Masulovic, D; Artiko, V

    2015-03-01

    Standardized perfusion value (SPV) is a universal indicator of tissue perfusion, normalized to the whole-body perfusion, which was proposed to simplify, unify and allow the interchangeability among the perfusion measurements and comparison between the tumor perfusion and metabolism. The aims of our study were to assess the standardized perfusion value (SPV) of the esophageal carcinoma, and its correlation with quantitative CT perfusion measurements: blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) of the same tumor volume samples, which were obtained by deconvolution-based CT perfusion analysis. Forty CT perfusion studies of the esophageal cancer were analyzed, using the commercial deconvolution-based CT perfusion software (Perfusion 3.0, GE Healthcare). The SPV of the esophageal tumor and neighboring skeletal muscle were correlated with the corresponding mean tumor and muscle quantitative CT perfusion parameter values, using Spearman's rank correlation coefficient (rS). Median SPV of the esophageal carcinoma (7.1; range: 2.8-13.4) significantly differed from the SPV of the skeletal muscle (median: 1.0; range: 0.4-2.4), (Z=-5.511, pCT perfusion measurements and statistically significant correlation was proved. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Effect of intranasally administered insulin on cerebral blood flow and perfusion

    DEFF Research Database (Denmark)

    Akintola, Abimbola A.; van Opstal, Anna M.; Westendorp, Rudi G.

    2017-01-01

    Insulin, a vasoactive modulator regulating peripheral and cerebral blood flow, has been consistently linked to aging and longevity. In this proof of principle study, using a randomized, double-blinded, placebo-controlled crossover design, we explored the effects of intranasally administered insul.......28±6.75 mL/100g/min versus 63.31±6.84 mL/100g/min, P=0.003). Thus, intranasal insulin improved tissue perfusion of the occipital cortical brain region and the thalamus in older adults.......Insulin, a vasoactive modulator regulating peripheral and cerebral blood flow, has been consistently linked to aging and longevity. In this proof of principle study, using a randomized, double-blinded, placebo-controlled crossover design, we explored the effects of intranasally administered insulin...... labelling. Total flow through the major cerebropetal arteries was unchanged in both young and old. In the older participants, intranasal insulin compared to placebo increased perfusion through the occipital gray matter (65.2±11.0 mL/100g/min vs 61.2±10.1 mL/100g/min, P=0.001), and in the thalamus (68...

  6. Cerebral perfusion pressure in women with preeclampsia is elevated even after treatment of elevated blood pressure.

    Science.gov (United States)

    Sonneveld, Milan J; Brussé, Ingrid A; Duvekot, Johannes J; Steegers, Eric A P; Grune, Frank; Visser, Gerhard H

    2014-05-01

    Cerebral perfusion pressure (CPP) is elevated in preeclampsia, and may predispose to cerebrovascular complications and progression to eclampsia. We estimated zero flow pressure (ZFP) and CPP using simultaneously obtained arterial blood pressure and middle cerebral artery blood flow velocity in 10 women with preeclampsia, all treated with methyldopa with or without nifedipine, and 18 healthy pregnant controls. Mean ± SD ZFP was lower in women with preeclampsia than in controls (16.8 ± 10.9 vs. 31.7 ± 15.0 mmHg, p = 0.01) whereas CPP was considerably higher (82.3 ± 17.7 vs. 55.0 ± 11.7 mmHg, p preeclampsia, but not in controls. Women with preeclampsia may have an increased cerebral perfusion due to a reduced ZFP and increased CPP despite treatment with antihypertensive medication. More rigorous antihypertensive therapy, aimed at reducing CPP, could result in a decrease in cerebral complications in women with preeclampsia. © 2014 Nordic Federation of Societies of Obstetrics and Gynecology.

  7. Blood Perfusion in Microfluidic Models of Pulmonary Capillary Networks: Role of Geometry and Hematocrit

    Science.gov (United States)

    Stauber, Hagit; Waisman, Dan; Sznitman, Josue; Technion-IIT Team; Department of Neonatology Carmel Medical Center; Faculty of Medicine-Technion IIT Collaboration

    2015-11-01

    Microfluidic platforms are increasingly used to study blood microflows at true physiological scale due to their ability to overcome manufacturing obstacle of complex anatomical morphologies, such as the organ-specific architectures of the microcirculation. In the present work, we utilize microfluidic platforms to devise in vitro models of the underlying pulmonary capillary networks (PCN), where capillary lengths and diameters are similar to the size of RBCs (~ 5-10 μm). To better understand flow characteristics and dispersion of red blood cells (RBCs) in PCNs, we have designed microfluidic models of alveolar capillary beds inspired by the seminal ``sheet flow'' model of Fung and Sobin (1969). Our microfluidic PCNs feature confined arrays of staggered pillars with diameters of ~ 5,7 and 10 μm, mimicking the dense structure of pulmonary capillary meshes. The devices are perfused with suspensions of RBCs at varying hematocrit levels under different flow rates. Whole-field velocity patterns using micro-PIV and single-cell tracking using PTV are obtained with fluorescently-labelled RBCs and discussed. Our experiments deliver a real-scale quantitative description of RBC perfusion characteristics across the pulmonary capillary microcirculation.

  8. Consideration of Normal Variation of Perfusion Measurements in the Quantitative Analysis of Myocardial Perfusion SPECT: Usefulness in Assessment of Viable Myocardium

    International Nuclear Information System (INIS)

    Paeng, Jin Chul; Lim, Il Han; Kim, Ki Bong; Lee, Dong Soo

    2008-01-01

    Although automatic quantification software of myocardial perfusion SPECT provides highly objective and reproducible quantitative measurements, there is still some limitation in the direct use of quantitative measurements. In this study we derived parameters using normal variation of perfusion measurements, and tried to test the usefulness of these parameters. In order to calculate normal variation of perfusion measurements on myocardial perfusion SPECT, 55 patients (M:F=28:27) of low-likelihood for coronary artery disease were enrolled and 201 Tl rest / 99m Tc-MIBI stress SPECT studies were performed. Using 20-segment model, mean (m) and standard deviation (SD) of perfusion were calculated in each segment. As a myocardial viability assessment group, another 48 patients with known coronary artery disease, who underwent coronary artery bypass graft surgery (CABG) were enrolled. 201 Tl rest / 99m Tc-MIBI stress / 201 Tl 24-hr delayed SPECT was performed before CABG and SPECT was followed up 3 months after CABG. From the preoperative 24-hr delayed SPECT, Q delay (perfusion measurement), Δ delay (Q delay .m) and Z delay ((Q delay .m)/SD) were defined and diagnostic performances of them for myocardial viability were evaluated using area under curve (AUC) on receiver operating characteristic (ROC) curve analysis. Segmental perfusion measurements showed considerable normal variations among segments. In men, the lowest segmental perfusion measurement was 51.8±6.5 and the highest segmental perfusion was 87.0±5.9, and they are 58.7±8.1 and 87.3±6.0, respectively in women. In the viability assessment, Q delay showed AUC of 0.633, while those for Δ delay and Z delay were 0.735 and 0.716, respectively. The AUCs of Δ delay and Z delay were significantly higher than that of Q delay (p=0.001 and 0.018, respectively). The diagnostic performance of Δ delay , which showed highest AUC, was 85% of sensitivity and 53% of specificity at the optimal cutoff of -24.7. On automatic

  9. Skeletal muscle perfusion measured by positron emission tomography during exercise

    NARCIS (Netherlands)

    Ament, W; Lubbers, J; Rakhorst, G; Vaalburg, W; Verkerke, GJ; Paans, AMJ; Willemsen, ATM

    1998-01-01

    The applicability of (H2O)-O-15-positron emission tomographic (PET) imaging for the assessment of skeletal muscle perfusion during exercise was investigated in five healthy subjects performing intermittent isometric contractions on a calf ergometer. The workload of the left calf muscles was kept

  10. Effect of combined VEGF165/ SDF-1 gene therapy on vascular remodeling and blood perfusion in cerebral ischemia.

    Science.gov (United States)

    Hu, Guo-Jie; Feng, Yu-Gong; Lu, Wen-Peng; Li, Huan-Ting; Xie, Hong-Wei; Li, Shi-Fang

    2017-09-01

    OBJECTIVE Therapeutic neovascularization is a promising strategy for treating patients after an ischemic stroke; however, single-factor therapy has limitations. Stromal cell-derived factor 1 (SDF-1) and vascular endothelial growth factor (VEGF) proteins synergistically promote angiogenesis. In this study, the authors assessed the effect of combined gene therapy with VEGF 165 and SDF-1 in a rat model of cerebral infarction. METHODS An adenoviral vector expressing VEGF 165 and SDF-1 connected via an internal ribosome entry site was constructed (Ad- VEGF 165 -SDF-1). A rat model of middle cerebral artery occlusion (MCAO) was established; either Ad- VEGF 165 -SDF-1 or control adenovirus Ad- LacZ was stereotactically microinjected into the lateral ventricle of 80 rats 24 hours after MCAO. Coexpression and distribution of VEGF 165 and SDF-1 were examined by reverse-transcription polymerase chain reaction, Western blotting, and immunofluorescence. The neurological severity score of each rat was measured on Days 3, 7, 14, 21, and 28 after MCAO. Angiogenesis and vascular remodeling were evaluated via bromodeoxyuridine and CD34 immunofluorescence labeling. Relative cerebral infarction volumes were determined by T2-weighted MRI and triphenyltetrazolium chloride staining. Cerebral blood flow, relative cerebral blood volume, and relative mean transmit time were assessed using perfusion-weighted MRI. RESULTS The Ad- VEGF 165 -SDF-1 vector mediated coexpression of VEGF 165 and SDF-1 in multiple sites around the ischemic core, including the cortex, corpus striatum, and hippocampal granular layer. Coexpression of VEGF 165 and SDF-1 improved neural function, reduced cerebral infarction volume, increased microvascular density and promoted angiogenesis in the ischemic penumbra, and improved cerebral blood flow and perfusion. CONCLUSIONS Combined VEGF 165 and SDF-1 gene therapy represents a potential strategy for improving vascular remodeling and recovery of neural function after

  11. Hypertension impairs myocardial blood perfusion reserve in subjects without regional myocardial ischemia

    International Nuclear Information System (INIS)

    Nakajima, Hiroshi; Onishi, Katsuya; Kurita, Tairo

    2010-01-01

    Quantitative analysis of myocardial perfusion MRI can provide noninvasive assessments of myocardial perfusion reserve (MPR), which is associated with endothelial function. Endothelial function is influenced by various factors, including hypertension, diabetes, dyslipidemia, renal dysfunction and anemia. The purpose of this study was to evaluate which risk factor is the strongest effector of MPR in subjects without regional myocardial ischemia. We studied 110 patients (66 years ±10, male 68%, hypertension 76%, diabetes mellitus (DM) 40% and dyslipidemia 65%) without regional myocardial ischemia. Adenosine triphosphate (ATP) stress and rest first-pass perfusion magnetic resonance (MR) images were acquired with a 1.5-T MR system, and MPR was calculated as the ratio of stress to rest myocardial blood flow (MBF). Average rest MBF in 110 patients was 1.07±0.62 ml min -1 g -1 , whereas stress MBF was 3.15±1.93 ml min -1 g -1 and the MPR was 3.33±1.82. Rest MBF correlated significantly with hematocrit, whereas stress MBF showed a strong correlation with estimated glomerular filtration rate (e-GFR). MPR was associated with hypertension, age, e-GFR, hematocrit and left ventricular mass index (LVMI). In multiple regression analysis, hypertension (P=0.003, β=-0.274) showed the strongest correlation with MPR among other risk factors, such as diabetes (P=ns), dyslipidemia (P=ns), e-GFR (P=ns), LVMI (P=0.007, β=-0.248) and hematocrit (P=ns) after adjusting age and gender. Hypertension is the most important effector of MPR in subjects without myocardial ischemia. (author)

  12. Experimental subarachnoid hemorrhage: subarachnoid blood volume, mortality rate, neuronal death, cerebral blood flow, and perfusion pressure in three different rat models.

    Science.gov (United States)

    Prunell, Giselle Fabiana; Mathiesen, Tiit; Diemer, Nils Henrik; Svendgaard, Niels-Aage

    2003-01-01

    To investigate which of three subarachnoid hemorrhage (SAH) models is the most suitable for studies of pathological and pathophysiological processes after SAH. SAH was induced in rats via intracranial endovascular perforation (perforation model), blood injection into the cisterna magna (300 microl), or blood injection into the prechiasmatic cistern (200 microl). The subarachnoid blood volume was quantitatively measured. Cerebral blood flow (CBF) (as assessed with laser Doppler flowmetry), intracranial pressure, and mean arterial blood pressure were recorded for 90 minutes after SAH. Mortality was recorded, and neuronal death was assessed in animals that survived 7 days after SAH. The subarachnoid blood volume was close to the injected amount after prechiasmatic SAH. In the other models, the volume varied between 40 and 480 microl. The mortality rates were 44% in the perforation SAH group, 25% in the prechiasmatic SAH group, and 0% in the cisterna magna SAH group; the corresponding values for neuronal death were 11, 44, and 28%. Cerebral perfusion pressure approached baseline values within 5 minutes after SAH in all three models. CBF decreased to approximately 35% of baseline values immediately after SAH in all groups; it gradually increased to normal values 15 minutes after SAH in the cisterna magna SAH group and to 60 and 89% of baseline values 90 minutes post-SAH in the perforation and prechiasmatic SAH groups. CBF was significantly correlated with the subarachnoid blood volume. The prechiasmatic SAH model seems to be the most suitable for study of the sequelae after SAH; it produces a significant decrease in CBF, an acceptable mortality rate, and substantial pathological lesions, with high reproducibility. The CBF reduction is predominantly dependent on the amount of subarachnoid blood.

  13. Perfusion measurements by micro-CT using prior image constrained compressed sensing (PICCS): initial phantom results.

    Science.gov (United States)

    Nett, Brian E; Brauweiler, Robert; Kalender, Willi; Rowley, Howard; Chen, Guang-Hong

    2010-04-21

    Micro-CT scanning has become an accepted standard for anatomical imaging in small animal disease and genome mutation models. Concurrently, perfusion imaging via tracking contrast dynamics after injection of an iodinated contrast agent is a well-established tool for clinical CT scanners. However, perfusion imaging is not yet commercially available on the micro-CT platform due to limitations in both radiation dose and temporal resolution. Recent hardware developments in micro-CT scanners enable continuous imaging of a given volume through the use of a slip-ring gantry. Now that dynamic CT imaging is feasible, data may be acquired to measure tissue perfusion using a micro-CT scanner (CT Imaging, Erlangen, Germany). However, rapid imaging using micro-CT scanners leads to high image noise in individual time frames. Using the standard filtered backprojection (FBP) image reconstruction, images are prohibitively noisy for calculation of voxel-by-voxel perfusion maps. In this study, we apply prior image constrained compressed sensing (PICCS) to reconstruct images with significantly lower noise variance. In perfusion phantom experiments performed on a micro-CT scanner, the PICCS reconstruction enabled a reduction to 1/16 of the noise variance of standard FBP reconstruction, without compromising the spatial or temporal resolution. This enables a significant increase in dose efficiency, and thus, significantly less exposure time is needed to acquire images amenable to perfusion processing. This reduction in required irradiation time enables voxel-by-voxel perfusion maps to be generated on micro-CT scanners. Sample perfusion maps using a deconvolution-based perfusion analysis are included to demonstrate the improvement in image quality using the PICCS algorithm.

  14. Perfusion measurements by micro-CT using prior image constrained compressed sensing (PICCS): initial phantom results

    International Nuclear Information System (INIS)

    Nett, Brian E; Chen, G-H; Brauweiler, Robert; Kalender, Willi; Rowley, Howard

    2010-01-01

    Micro-CT scanning has become an accepted standard for anatomical imaging in small animal disease and genome mutation models. Concurrently, perfusion imaging via tracking contrast dynamics after injection of an iodinated contrast agent is a well-established tool for clinical CT scanners. However, perfusion imaging is not yet commercially available on the micro-CT platform due to limitations in both radiation dose and temporal resolution. Recent hardware developments in micro-CT scanners enable continuous imaging of a given volume through the use of a slip-ring gantry. Now that dynamic CT imaging is feasible, data may be acquired to measure tissue perfusion using a micro-CT scanner (CT Imaging, Erlangen, Germany). However, rapid imaging using micro-CT scanners leads to high image noise in individual time frames. Using the standard filtered backprojection (FBP) image reconstruction, images are prohibitively noisy for calculation of voxel-by-voxel perfusion maps. In this study, we apply prior image constrained compressed sensing (PICCS) to reconstruct images with significantly lower noise variance. In perfusion phantom experiments performed on a micro-CT scanner, the PICCS reconstruction enabled a reduction to 1/16 of the noise variance of standard FBP reconstruction, without compromising the spatial or temporal resolution. This enables a significant increase in dose efficiency, and thus, significantly less exposure time is needed to acquire images amenable to perfusion processing. This reduction in required irradiation time enables voxel-by-voxel perfusion maps to be generated on micro-CT scanners. Sample perfusion maps using a deconvolution-based perfusion analysis are included to demonstrate the improvement in image quality using the PICCS algorithm.

  15. Characteristic patterns of cerebral blood perfusion and cognitive impairment in patients with Parkinsons disease

    International Nuclear Information System (INIS)

    Jeong, Y. J.; Park, M. J.; Cha, J. G.; Kim, S. H.; Kim, J. W.; Kang, D. Y.

    2005-01-01

    Parkinsons disease (PD) is a neurodegenerative disorder that represents cognitive impairment as well as motor symptoms. Even in the early stages of PD, cognitive alterations can be demonstrated by careful neuropsychological test. The purposes of this study are to investigate the pattern of cognitive impairment and the regional cerebral blood flow (rCBF) using Tc-99m HMPAO SPECT in patients with PD. One hundred and twenty two patients with PD and 35 control subjects participated in this study. Patients with PD who had dementia clinically or K-MMSE score below 25 points or with severe motor dysfunction to interfere with the tests were also excluded. They were all matched for age (61±10 vs 61±8), education periods (8.8±4.9 vs 8.8±4.5), and K-MMSE score (27±1.6 vs 27±1.5). All subjects were evaluated using the Seoul Neuropsychological Screening Battery (SNSB) and Tc-99m HMPAO SPECT with SPM software to measure rCBF. Patients with PD performed worse in digit span backward, Rey Complex Figure Test, visual memory, semantic fluency, stroop test, and alternating hand movement test(p<0.05) compared with control group. On SNSB test, 100 patients (82.0%) showed some abnormalities. Eighty-six patients (70.5%) showed frontal dysfunction, 47 (38.5%) memory impairment, 33 (27.0%) language dysfunction, 25 (20.5%) attention deficit and 22 (18.3%) visuospatial dysfunction in the order of frequency. Eight patients with PD showed single memory domain MCI and 28 single non-memory domain MCI (20 frontal dysfunction). Multiple domain MCI was found in 64 patients with PD. SPM analysis of the SPECT image revealed multiple perfusion deficit in the both frontal, temporal, both limbic lobes, Lt. parietal and Lt. Putamen. It is concluded that abnormalities of cognitive function be detected very commonly in patients with PD. MCI in PD patients is most frequently involved in the item of frontal lobe function. SPECT image might be helpful to explain cognitive impairment in some PD patients

  16. Characteristic patterns of cerebral blood perfusion and cognitive impairment in patients with Parkinsons disease

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y. J.; Park, M. J.; Cha, J. G.; Kim, S. H.; Kim, J. W.; Kang, D. Y. [Dong-A University College of medicine, Pusan (Korea, Republic of)

    2005-07-01

    Parkinsons disease (PD) is a neurodegenerative disorder that represents cognitive impairment as well as motor symptoms. Even in the early stages of PD, cognitive alterations can be demonstrated by careful neuropsychological test. The purposes of this study are to investigate the pattern of cognitive impairment and the regional cerebral blood flow (rCBF) using Tc-99m HMPAO SPECT in patients with PD. One hundred and twenty two patients with PD and 35 control subjects participated in this study. Patients with PD who had dementia clinically or K-MMSE score below 25 points or with severe motor dysfunction to interfere with the tests were also excluded. They were all matched for age (61{+-}10 vs 61{+-}8), education periods (8.8{+-}4.9 vs 8.8{+-}4.5), and K-MMSE score (27{+-}1.6 vs 27{+-}1.5). All subjects were evaluated using the Seoul Neuropsychological Screening Battery (SNSB) and Tc-99m HMPAO SPECT with SPM software to measure rCBF. Patients with PD performed worse in digit span backward, Rey Complex Figure Test, visual memory, semantic fluency, stroop test, and alternating hand movement test(p<0.05) compared with control group. On SNSB test, 100 patients (82.0%) showed some abnormalities. Eighty-six patients (70.5%) showed frontal dysfunction, 47 (38.5%) memory impairment, 33 (27.0%) language dysfunction, 25 (20.5%) attention deficit and 22 (18.3%) visuospatial dysfunction in the order of frequency. Eight patients with PD showed single memory domain MCI and 28 single non-memory domain MCI (20 frontal dysfunction). Multiple domain MCI was found in 64 patients with PD. SPM analysis of the SPECT image revealed multiple perfusion deficit in the both frontal, temporal, both limbic lobes, Lt. parietal and Lt. Putamen. It is concluded that abnormalities of cognitive function be detected very commonly in patients with PD. MCI in PD patients is most frequently involved in the item of frontal lobe function. SPECT image might be helpful to explain cognitive impairment in some

  17. Effects of perfusion detect on the measurement of left ventricular mass, ventricular volume and post-stress left ventricular ejection fraction in gated myocardial perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Byeong Cheol; Bae, Sun Keun; Lee, Sang Woo; Jeong, Sin Young; Lee, Jae Tae; Lee, Kyu Bo [Kyungpook National University Medical School, Daegu (Korea, Republic of)

    2002-12-01

    The presence of perfusion defect may influence the left ventricular mass (LVM) measurement by quantitative gated myocardial perfusion SPECT (QGS), and ischemic myocardium, usually showing perfusion defect may produce post-stress LV dysfunction. This study was aimed to evaluated the effects of extent and reversibility of perfusion defect on the automatic measurement of LVM by QGS and to investigate the effect of reversibility of perfusion defect on post-stress LV dysfunction. Forty-six patients (male/female=34:12, mean age=64 years) with perfusion defect on myocardial perfusion SPECT underwent rest and post-stress QGS. Forty patients (87%) showed reversible defect. End-diastolic volume (EDV), end-systolic volume (ESV), LV ejection fraction (EF), and LV myocardial volume were obtained from QGS by autoquant program, and LVM was calculated by multiplying the LV myocardial volume by the specific gravity of myocardium. LVMs measured at rest and post-stress QGS showed good correlation, and higher correlation was founded in the subjects with fixed perfusion defect and with small defect (smaller than 20%). There were no significant differences in EDVs, ESVs and EFs between obtained by rest and post-stress QGS in patients with fixed myocardial defect. Whereas, EF obtained by post-stress QGS was lower than that by rest QGS in patients with reversible defect and 10 (25%) of them showed decreases in EF more than 5% in post-stress QGS, as compared to that of rest QGS. Excellent correlations of EDVs, ESVs, EFs between rest and post-stress QGS were noted. Patients with fixed defect had higher correlation between defect can affect LVM measurement by QGS and patients with reversible defect shows post-stress LV dysfunction more frequently than patients with fixed perfusion defect.

  18. Simultaneous measurement of pO2 and perfusion in the rabbit kidney in vivo.

    Science.gov (United States)

    O'Connor, Paul M; Anderson, Warwick P; Kett, Michelle M; Evans, Roger G

    2007-01-01

    Recently, a combined probe has been developed capable of simultaneous measurement of local tissue pO2 (fluorescence oximetry) and microvascular perfusion (laser Doppler flux) within the same local region. The aim of the current study was to test the utility of these combined probes to measure pO2 and perfusion in the kidney. Studies were performed in anesthetized, artificially ventilated rabbits (n=7). Baseline measurements of renal medullary perfusion and pO2 obtained using combined probes (537 +/- 110 units & 28.7 +/- 6.l mmHg, respectively) were indistinguishable from those obtained using independent probes (435 +/- 102 units & 26.9 +/- 6.4 mmHg). Baseline measurements of renal cortical pO2 were also similar between combined (9.7 +/- 1.6 mmHg) and independent probes (9.5 +/- 2.3 mmHg). Baseline levels of cortical perfusion however, were significantly greater when measured using independent probes (1130 +/- 114 units) compared to combined probes (622 +/- 59 units; P pO2 resulting from graded stimulation of the renal nerves were not significantly different when measured using combined probes to those obtained using independent probes. We conclude that combined probes are equally suitable to independent probes for tissue pO2 and microvascular perfusion measurement in the kidney. Our results raise some concerns regarding the accuracy of these OxyLite fluorescence probes for pO2 measurement in the kidney, particularly within the renal cortex.

  19. Validation of Perfusion Quantification with 3D Gradient Echo Dynamic Contrast-Enhanced Magnetic Resonance Imaging Using a Blood Pool Contrast Agent in Skeletal Swine Muscle.

    Directory of Open Access Journals (Sweden)

    Stefan Hindel

    Full Text Available The purpose of our study was to validate perfusion quantification in a low-perfused tissue by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI with shared k-space sampling using a blood pool contrast agent. Perfusion measurements were performed in a total of seven female pigs. An ultrasonic Doppler probe was attached to the right femoral artery to determine total flow in the hind leg musculature. The femoral artery was catheterized for continuous local administration of adenosine to increase blood flow up to four times the baseline level. Three different stable perfusion levels were induced. The MR protocol included a 3D gradient-echo sequence with a temporal resolution of approximately 1.5 seconds. Before each dynamic sequence, static MR images were acquired with flip angles of 5°, 10°, 20°, and 30°. Both static and dynamic images were used to generate relaxation rate and baseline magnetization maps with a flip angle method. 0.1 mL/kg body weight of blood pool contrast medium was injected via a central venous catheter at a flow rate of 5 mL/s. The right hind leg was segmented in 3D into medial, cranial, lateral, and pelvic thigh muscles, lower leg, bones, skin, and fat. The arterial input function (AIF was measured in the aorta. Perfusion of the different anatomic regions was calculated using a one- and a two-compartment model with delay- and dispersion-corrected AIFs. The F-test for model comparison was used to decide whether to use the results of the one- or two-compartment model fit. Total flow was calculated by integrating volume-weighted perfusion values over the whole measured region. The resulting values of delay, dispersion, blood volume, mean transit time, and flow were all in physiologically and physically reasonable ranges. In 107 of 160 ROIs, the blood signal was separated, using a two-compartment model, into a capillary and an arteriolar signal contribution, decided by the F-test. Overall flow in hind leg muscles

  20. Wet cupping therapy improves local blood perfusion and analgesic effects in patients with nerve-root type cervical spondylosis.

    Science.gov (United States)

    Meng, Xiang-Wen; Wang, Ying; Piao, Sheng-Ai; Lv, Wen-Tao; Zhu, Cheng-Hui; Mu, Ming-Yuan; Li, Dan-Dan; Liu, Hua-Peng; Guo, Yi

    2018-01-15

    To observe wet cupping therapy (WCT) on local blood perfusion and analgesic effects in patients with nerve-root type cervical spondylosis (NT-CS). Fifty-seven NT-CS patients were randomly divided into WCT group and Jiaji acupoint-acupuncture (JA) group according a random number table. WCT group (30 cases) was treated with WCT for 10 min, and JA group (27 cases) was treated with acupuncture for 10 min. The treatment effificacies were evaluated with a Visual Analogue Scale (VAS). Blood perfusion at Dazhui (GV 14) and Jianjing (GB 21) acupoints (affected side) was observed with a laser speckle flflowmetry, and its variations before and after treatment in both groups were compared as well. In both groups, the VAS scores signifificantly decreased after the intervention (P<0.01), while the blood perfusion at the two acupoints signifificantly increased after intervention (P<0.05); however, the increasement magnitude caused by WCT was obvious compared with JA (P<0.05). WCT could improve analgesic effects in patients with NT-CS, which might be related to increasing local blood perfusion of acupunct points.

  1. Absolute Versus Relative Myocardial Blood Flow by Dynamic CT Myocardial Perfusion Imaging in Patients With Anatomic Coronary Artery Disease

    NARCIS (Netherlands)

    Wichmann, Julian L.; Meinel, Felix G.; Schoepf, U. Joseph; Lo, Gladys G.; Choe, Yeon Hyeon; Wang, Yining; Vliegenthart, Rozemarijn; Varga-Szemes, Akos; Muscogiuri, Giuseppe; Cannao, Paola M.; De Cecco, Carlo N.

    OBJECTIVE. The purpose of this study was to evaluate differences in the diagnostic accuracy of absolute and relative territorial myocardial blood flow (MBF) derived from stress dynamic CT myocardial perfusion imaging (MPI) for the detection of significant coronary artery stenosis. MATERIALS AND

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-15

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

  3. Spatio-temporal cerebral blood flow perfusion patterns in cortical spreading depression

    Science.gov (United States)

    Verisokin, Andrey Yu.; Verveyko, Darya V.; Postnov, Dmitry E.

    2017-04-01

    Cortical spreading depression (CSD) is an example of one of the most common abnormalities in biophysical brain functioning. Despite the fact that there are many mathematical models describing the cortical spreading depression (CSD), most of them do not take into consideration the role of redistribution of cerebral blood flow (CBF), that results in the formation of spatio-temporal patterns. The paper presents a mathematical model, which successfully explains the CBD role in the CSD process. Numerical study of this model has revealed the formation of stationary dissipative structures, visually analogous to Turing structures. However, the mechanism of their formation is not diffusion. We show these structures occur due to another type of spatial coupling, that is related to tissue perfusion rate. The proposed model predicts that at similar state of neurons the distribution of blood flow and oxygenation may by different. Currently, this effect is not taken into account when the Blood oxygen-level dependent (BOLD) contrast imaging used in functional magnetic resonance imaging (fMRI). Thus, the diagnosis on the BOLD signal can be ambiguous. We believe that our results can be used in the future for a more correct interpretation of the data obtained with fMRI, NIRS and other similar methods for research of the brain activity.

  4. 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.

  5. Evaluation of Perfusion and Thermal Parameters of Skin Tissue Using Cold Provocation and Thermographic Measurements

    Directory of Open Access Journals (Sweden)

    Strąkowska Maria

    2016-09-01

    Full Text Available Measurement of the perfusion coefficient and thermal parameters of skin tissue using dynamic thermography is presented in this paper. A novel approach based on cold provocation and thermal modelling of skin tissue is presented. The measurement was performed on a person’s forearm using a special cooling device equipped with the Peltier module. The proposed method first cools the skin, and then measures the changes of its temperature matching the measurement results with a heat transfer model to estimate the skin perfusion and other thermal parameters. In order to assess correctness of the proposed approach, the uncertainty analysis was performed.

  6. Comparison of Optic Nerve Head Blood Flow Autoregulation among Quadrants Induced by Decreased Ocular Perfusion Pressure during Vitrectomy

    Directory of Open Access Journals (Sweden)

    Ryuya Hashimoto

    2017-01-01

    Full Text Available Purpose. The present study aimed to examine changes in optic nerve head (ONH blood flow autoregulation in 4 quadrants (superior, nasal, inferior, and temporal with decreased ocular perfusion pressure (OPP during vitrectomy in order to determine whether there is a significant difference of autoregulatory capacity in response to OPP decrease at each ONH quadrant. Methods. This study included 24 eyes with an epiretinal membrane or macular hole that underwent vitrectomy at Toho University Sakura Medical Center. Following vitrectomy, the tissue mean blur rate (MBR, which reflects ONH blood flow, was measured. Mean tissue MBRs in the four quadrants were generated automatically in the software analysis report. Measurements were conducted before and 5 and 10 min after intraocular pressure (IOP elevation of approximately 15 mmHg in the subjects without systemic disorders. Results. The baseline tissue MBR of the temporal quadrant was significantly lower than that of the other 3 quadrants (all P<0.05. However, the time courses of tissue MBR in response to OPP decrease were not significantly different among the four quadrants during vitrectomy (P=0.23. Conclusions. There is no significant difference in the autoregulatory capacity of the four ONH quadrants in patients without systemic disorders during vitrectomy.

  7. Beam hardening correction in CT myocardial perfusion measurement

    Science.gov (United States)

    So, Aaron; Hsieh, Jiang; Li, Jian-Ying; Lee, Ting-Yim

    2009-05-01

    This paper presents a method for correcting beam hardening (BH) in cardiac CT perfusion imaging. The proposed algorithm works with reconstructed images instead of projection data. It applies thresholds to separate low (soft tissue) and high (bone and contrast) attenuating material in a CT image. The BH error in each projection is estimated by a polynomial function of the forward projection of the segmented image. The error image is reconstructed by back-projection of the estimated errors. A BH-corrected image is then obtained by subtracting a scaled error image from the original image. Phantoms were designed to simulate the BH artifacts encountered in cardiac CT perfusion studies of humans and animals that are most commonly used in cardiac research. These phantoms were used to investigate whether BH artifacts can be reduced with our approach and to determine the optimal settings, which depend upon the anatomy of the scanned subject, of the correction algorithm for patient and animal studies. The correction algorithm was also applied to correct BH in a clinical study to further demonstrate the effectiveness of our technique.

  8. Blood flow and vascular reactivity in collaterally perfused brain tissue. Evidence of an ischemic penumbra in patients with acute stroke

    DEFF Research Database (Denmark)

    Olsen, T S; Larsen, B; Herning, M

    1983-01-01

    In a group of 48 patients with completed stroke, 8 patients had viable collaterally perfused brain tissue which was accessible for rCBF recordings with a two dimensional technique. All 8 had deep subcortical infarcts on CT-scan, and angiographic occlusion of the arteries normally supplying...... the infarcted territory. The brain tissue overlying the deep infarcts appeared normal on CT-scan and was supplied by collateral circulation. rCBF was measured in all within 72 hours after the stroke. The intra-carotid Xe-133 injection method and a 254 multidetector camera were used to study rCBF. Relatively...... ischemic low flow areas were a constant finding in the collaterally perfused tissue. In 6 of the patients, the collaterally perfused part of the brain had low flow values comparable to those of an "ischemic penumbra" (viable, but functionally depressed brain tissue due to inadequate perfusion...

  9. Brain capillary transit time heterogeneity in healthy volunteers measured by dynamic contrast-enhanced T1-weighted perfusion MRI

    DEFF Research Database (Denmark)

    Larsson, Henrik B.W.; Vestergaard, Mark B.; Lindberg, Ulrich

    2017-01-01

    based on a gamma-variate model of the capillary transit time distribution. In addition, we wanted to investigate if a subtle increase of the blood–brain barrier permeability can be incorporated into the model, still allowing estimation of CTH. Materials and Methods: Twenty-three healthy subjects were...... scanned at 3.0T MRI system applying DCE-MRI and using a gamma-variate model to estimate CTH as well as cerebral blood flow (CBF), cerebral blood volume (CBV), and permeability of the blood–brain barrier, measured as the influx constant Ki. For proof of principle we also investigated three patients...... response function. Conclusion: Our results open the possibility of characterizing brain perfusion by the capillary transit time distribution using DCE-MRI, theoretically a determinant of efficient blood to brain transport of important substances. Level of Evidence: 2. J. MAGN. RESON. IMAGING 2017;45:1809–1820....

  10. Correction of disorders in tissue perfusion, blood coagulation and fibrinolysis with Orbita apparatus on terahertz waves of cell metabolites

    Directory of Open Access Journals (Sweden)

    Vyacheslav F. Kirichuk

    2013-02-01

    Full Text Available This article contains information on principle of operation, technical parameters and possible application of Orbita {transliteration from Russian} apparatus for hemodynamic, fibrinolytic and peripheral perfusion disorders treatment. A single exposure to terahertz waves emitted by Orbita apparatus, corresponding to frequencies of molecular absorption and emission spectra of atmospheric oxygen (129.0 GHz, completely cures coagulant and fibrinolytic disorders of animals with acute immobilization stress. A course of treatment with electromagnetic waves corresponding to frequencies of molecular absorption and emission spectra of nitrogen oxide (150.176 – 150.664 leads to normalization of disrupted peripheral tissue perfusion parameters of animal undergoing treatment and stimulates basal and induced output of nitrogen oxide. This leads to decrease in peripheral vascular resistance to microcirculation and increase in blood flow to microvasculature. Experimental data provided in this article serves as a proof of viability of Orbita apparatus for treatment of coagulant, fibrinolytic and tissue perfusion disorders.

  11. SHORT-TERM EFFECTS OF EXERCISE ON OPTIC NERVE AND MACULAR PERFUSION MEASURED BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

    Science.gov (United States)

    Alnawaiseh, Maged; Lahme, Larissa; Treder, Maximilian; Rosentreter, André; Eter, Nicole

    2017-09-01

    To evaluate the effects of exercise on optic nerve and macular perfusion using optical coherence tomography angiography. Thirteen eyes of 13 healthy volunteers were examined using a high-speed and high-resolution spectral-domain optical coherence tomography XR Avanti with a split-spectrum amplitude-decorrelation angiography algorithm. Blood pressure, heart rate, the mean area of the foveal avascular zone , and flow density on the optic nerve head and macula, before and after exercise were measured and analyzed. Mean patient age was 27.3 ± 3.5 years. Heart rate, systolic and diastolic blood pressure increased significantly after exercise (P < 0.001). The mean area of the foveal avascular zone did not change significantly after exercise (before: 0.27 ± 0.07 mm; after: 0.26 ± 0.07 mm; P = 0.10). The peripapillary and the parafoveal flow density decreased significantly after exercise (peripapillary: before: 65.1 ± 2.1; after: 62.3 ± 3.0; P < 0.001 and parafoveal: before: 56.7 ± 1.3; after: 55.6 ± 1.5; P = 0.007). Increased physical activity induced significant changes in optic nerve and macular perfusion, which were measured using split-spectrum amplitude-decorrelation angiography optical coherence tomography angiography. In studies that aim to evaluate optic nerve and macular perfusion using optical coherence tomography angiography, it should be strongly recommended that patients rest before imaging is performed and that data concerning systemic circulation including blood pressure and pulse is included within the evaluation.

  12. Short-term effects of brimonidine/timolol and dorzolamide/timolol on ocular perfusion pressure and blood flow in glaucoma.

    Science.gov (United States)

    Siesky, Brent; Harris, Alon; Ehrlich, Rita; Cantor, Louis; Shoja, Mohammadali M; Rusia, Deepam; Hollander, David A; Abrams, Leslie; Williams, Julia M; Shoshani, Yochai

    2012-01-01

    To examine the comparative short-term effects of brimonidine/timolol and dorzolamide/timolol on ocular perfusion pressure and retrobulbar blood flow in patients with primary open angle glaucoma (OAG). In a prospective, randomized, double-blind, crossover study, intraocular pressure (IOP), blood pressure (BP), ocular perfusion pressure (OPP), and retrobulbar hemodynamics were assessed in 15 patients with OAG (mean age 68.1 years, eight women) with well controlled IOP. IOP was measured by Goldman applanation tonometery and color Doppler imaging was utilized to assess the retrobulbar blood vessels before and 1 month after treatment with topical brimonidine/timolol and dorzolamide/timolol. Statistical analysis was performed by Friedman two-way analysis of variance by ranks and post-hoc Wilcoxon signed rank test for multiple comparisons with Holm's sequential Bonferroni procedure. P values <0.05 were considered statistically significant. The Friedman test and subsequent post-hoc analysis indicated that IOP, BP, OPP, and retrobulbar blood flow velocities did not significantly differ between brimonidine/timolol and dorzolamide/timolol after 1-month treatment administration in patients with OAG and well controlled IOP. In this cohort of patients with OAG, short-term treatment with brimonidine/timolol and dorzolamide/timolol results in similar effects on OPP and retrobulbar blood flow velocities.

  13. Estimation of rat muscle blood flow by microdialysis probes perfused with ethanol, [14C]ethanol, and 3H2O

    DEFF Research Database (Denmark)

    Stallknecht, B; Donsmark, M; Enevoldsen, L H

    1999-01-01

    rates ranging from 0 to 21 ml. 100 g-1. min-1. The microdialysis probes were perfused at 2 microliter/min with perfusate containing ethanol, [14C]ethanol, and 3H2O. Within and between experiments outflow-to-inflow ratios (o/i) generally varied inversely with blood flow. When a low flow or no flow....... Ethanol and [14C]ethanol o/i ratios did not differ. 3H2O o/i paralleled ethanol and [14C]ethanol o/i ratios but it was significantly lower. In conclusion, differences in skeletal muscle blood flow can be detected by the microdialysis technique. However, the slow changes in o/i, in particular at low blood...... flow rates, limit the usefulness of the technique for measuring dynamic changes in blood flow; caution must also be exerted during muscle contractions. 3H2O and [14C]ethanol are good alternatives to ethanol in the determination of blood flow by microdialysis....

  14. Quantitative assessment of magnetic resonance derived myocardial perfusion measurements using advanced techniques: microsphere validation in an explanted pig heart system

    NARCIS (Netherlands)

    Schuster, Andreas; Zarinabad, Niloufar; Ishida, Masaki; Sinclair, Matthew; van den Wijngaard, Jeroen P. H. M.; Morton, Geraint; Hautvast, Gilion L. T. F.; Bigalke, Boris; van Horssen, Pepijn; Smith, Nicolas; Spaan, Jos A. E.; Siebes, Maria; Chiribiri, Amedeo; Nagel, Eike

    2014-01-01

    Cardiovascular Magnetic Resonance (CMR) myocardial perfusion imaging has the potential to evolve into a method allowing full quantification of myocardial blood flow (MBF) in clinical routine. Multiple quantification pathways have been proposed. However at present it remains unclear which algorithm

  15. Effect of steroid on brain tumors and surround edemas : observation with regional cerebral blood volume (rCBV) maps of perfusion MRI

    International Nuclear Information System (INIS)

    Choi, Ju Youl; Sun, Joo Sung; Kim, Sun Yong; Kim, Ji Hyung; Suh, Jung Ho; Cho, Kyung Gi; Kim, Jang Sung

    2000-01-01

    To observe the hemodynamic change in brain tumors and peritumoral edemas after steroid treatment, and then investigate the clinical usefulness of perfusion MRI. We acquired conventional and perfusion MR images in 15 patients with various intracranial tumors (4 glioblastoma multiformes, 4 meningiomas, 3 metastatic tumors, 1 anaplastic ependymoma, 1 anaplastic astrocytoma, 1 hemangioblastoma, and 1 pilocytic astrocytoma). For perfusion MR imaging, a 1.5T unit employing the gradient-echo EPI technique was used, and further perfusion MR images were obtained 2-10 days after intravenous steroid therapy. After processing of the raw data, regional cerebral blood volume (rCBV) maps were reconstructed. The maps were visually evaluated by comparing relative perfusion in brain tumors and peritumoral edemas with that in contralateral white matter. Objective evaluations were performed by comparing the perfusion ratios of brain tumors and peritumoral edemas. Visual evaluations of rCBV maps, showed that in most brain tumors (67%, 10/15), perfusion was high before steroid treatment and showed in (80%, 12/15) decreased afterwards. Objective evaluation, showed that in all brain tumors, perfusion decreased. Visual evaluation of perfusion change in peritumoral edemas revealed change in only one case, but objective evaluation indicated that perfusion decreased significantly in all seven cases. rCBV maps acquired by perfusion MR imaging can provide hemodynamic information about brain tumors and peritumoral edemas. Such maps could prove helpful in the preoperative planning of brain tumor surgery and the monitoring of steroid effects during conservative treatment. (author)

  16. Noninvasive estimation of oxygen consumption in human calf muscle through combined NMR measurements of ASL perfusion and T₂ oxymetry.

    Science.gov (United States)

    Decorte, Nicolas; Buehler, Tania; Caldas de Almeida Araujo, Ericky; Vignaud, Alexandre; Carlier, Pierre G

    2014-01-01

    The objective of this work was to demonstrate the feasibility of measuring muscle O2 consumption (V˙O2) noninvasively with a combination of functional nuclear magnetic resonance (NMR) imaging methods, and to verify that changes in muscle V˙O2 can be detected with a temporal resolution compatible with physiological investigation and patient ease. T2-based oxymetry of arterial and venous blood was combined with the arterial-spin labeling (ASL)-based determination of muscle perfusion. These measurements were performed on 8 healthy volunteers under normoxic and hypoxic conditions in order to assess the sensitivity of measurements over a range of saturation values. Blood samples were drawn simultaneously and used to titrate blood T2 measurements versus hemoglobin O2 saturation (%HbO2) in vitro. The in vitro calibration curve of blood T2 fitted very well with the %HbO2 (r(2): 0.95). The in vivo venous T2 measurements agreed well with the in vitro measurements (intraclass correlation coefficient 0.82, 95% confidence interval 0.61-0.91). Oxygen extraction at rest decreased in the calf muscles subjected to hypoxia (p = 0.031). The combination of unaltered muscle perfusion and pinched arteriovenous O2 difference (p = 0.038) pointed towards a reduced calf muscle V˙O2 during transient hypoxia (p = 0.018). The results of this pilot study confirmed that muscle O2 extraction and V˙O2 can be estimated noninvasively using a combination of functional NMR techniques. Further studies are needed to confirm the usefulness in a larger sample of volunteers and patients. © 2014 S. Karger AG, Basel.

  17. Experimental flow and perfusion measurement in an animal model with magnetic resonance tomography

    International Nuclear Information System (INIS)

    Schoenberg, S.O.; Bock, M.; Just, A.

    2001-01-01

    Aim. Validation of non-invasive methods for morphologic and functional imaging of the kidney under physiologic and pathophysiologic conditions. Material and Methods. In chronically instrumented animals (foxhounds) comparative measurements of renal flow and perfusion were performed. Magnetic resonance imaging techniques were compared to data obtained from implanted flow probes and total kidney weight post mortem. In the MR system, different degrees of renal artery stenosis could be induced by means of an implanted inflatable cuff. The degree of stenosis was verified with high-resolution 3D contrast-enhanced MR angiography (3D-CE-MRA) using an intravascular contrast agent. Results. The MR-data agreed well with the invasively obtained results. Artifacts resulting from the implanted flow probes and other devices could be kept to a minimum due to appropriate selection of the probe materials and measurement strategies. Stenoses could be reproduced reliably and quantified from the induced morphologic and functional changes. Conclusion. Morphologic and functional MR techniques are well suited for non-invasive in vivo assessment of renal blood flow physiology. (orig.) [de

  18. Assessment of Blood Flow in Hepatocellular Carcinoma: Correlations of Computed Tomography Perfusion Imaging and Circulating Angiogenic Factors

    Directory of Open Access Journals (Sweden)

    Chen-Pin Chou

    2013-08-01

    Full Text Available Hepatocellular carcinoma (HCC is a highly vascular tumor through the process of angiogenesis. To evaluate more non-invasive techniques for assessment of blood flow (BF in HCC, this study examined the relationships between BF of HCC measured by computer tomography (CT perfusion imaging and four circulating angiogenic factors in HCC patients. Interleukin 6 (IL-6, interleukin 8 (IL-8, vascular endothelial growth factor (VEGF, and platelet derived growth factor (PDGF in plasma were measured using Bio-Plex multiplex immunoassay in 21 HCC patients and eight healthy controls. Circulating IL-6, IL-8 and VEGF showed higher concentrations in HCC patients than in controls (p < 0.05, and predicted HCC occurrence better than chance (p < 0.01. Twenty-one patients with HCC received 21-phase liver imaging using a 64-slice CT. Total BF, arterial BF, portal BF, arterial fraction (arterial BF/total BF of the HCC and surrounding liver parenchyma, and HCC-parenchyma ratio were measured using a dual-vessel model. After analyzing the correlations between BF in HCC and four circulating angiogenic factors, we found that the HCC-parenchyma ratio of arterial BF showed a significantly positive correlation with the level of circulating IL-8 (p < 0.05. This circulating biomarker, IL-8, provides a non-invasive tool for assessment of BF in HCC.

  19. Quantitative renal perfusion measurements in a rat model of acute kidney injury at 3T: testing inter- and intramethodical significance of ASL and DCE-MRI.

    Directory of Open Access Journals (Sweden)

    Fabian Zimmer

    Full Text Available OBJECTIVES: To establish arterial spin labelling (ASL for quantitative renal perfusion measurements in a rat model at 3 Tesla and to test the diagnostic significance of ASL and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI in a model of acute kidney injury (AKI. MATERIAL AND METHODS: ASL and DCE-MRI were consecutively employed on six Lewis rats, five of which had a unilateral ischaemic AKI. All measurements in this study were performed on a 3 Tesla MR scanner using a FAIR True-FISP approach and a TWIST sequence for ASL and DCE-MRI, respectively. Perfusion maps were calculated for both methods and the cortical perfusion of healthy and diseased kidneys was inter- and intramethodically compared using a region-of-interest based analysis. RESULTS/SIGNIFICANCE: Both methods produce significantly different values for the healthy and the diseased kidneys (P<0.01. The mean difference was 147±47 ml/100 g/min and 141±46 ml/100 g/min for ASL and DCE-MRI, respectively. ASL measurements yielded a mean cortical perfusion of 416±124 ml/100 g/min for the healthy and 316±102 ml/100 g/min for the diseased kidneys. The DCE-MRI values were systematically higher and the mean cortical renal blood flow (RBF was found to be 542±85 ml/100 g/min (healthy and 407±119 ml/100 g/min (AKI. CONCLUSION: Both methods are equally able to detect abnormal perfusion in diseased (AKI kidneys. This shows that ASL is a capable alternative to DCE-MRI regarding the detection of abnormal renal blood flow. Regarding absolute perfusion values, nontrivial differences and variations remain when comparing the two methods.

  20. Studies on blood supply of liver metastasis with DSA, CT and portal vein perfusion CT during superior mesenteric arterial portography

    International Nuclear Information System (INIS)

    Li Zhigang; Shi Gaofeng; Huang Jingxiang; Li Shunzong; Liang Guoqing; Wang Hongguang; Han Pengyin; Wang Qi; Gu Tieshu

    2008-01-01

    Objective: To probe the blood supply of liver metastasis by celiac artery, proper hepatic artery DSA, portal vein perfusion CT during superior mesenteric arterial portography (PCTAP). Methods: One hundred patients with liver metastases were examined prospectively by plain CT scan, multiphase enhanced CT scan, celiac arteriography and proper hepatic arteriography. Of them, 56 patients were examined by PCTAP. All primary lesions were confirmed by operation and (or) pathology examination. In order to investigate the blood supply of metastasis lesions, the software of Photoshop was used to obtain the time-attenuation curves (TDC) of tumor center, tumor edge, portal vein and normal liver parenchyma adjacent to the tumor to calculate liver perfusion for DSA image analysis, while a deconvolution model from CT perfusion software was designed for the dual blood supply. Results: DSA findings: TDC of proper hepatic arteriography showed: the mean peak concentration (K value) in tumor centers was (67 ± 12)%, and it was (76 ± 15)% for peritumor tissue, (51 ± 10)% in normal liver parenchyma. TDC of celiac arteriogaphy showed that the contrast concentration of tumor centers and tumor edge increased fast in early stage, then maintained a slight upward plateau, in the meanwhile, the contrast concentration of normal liver parenchyma kept increasing slowly. PCTAP findings: tumors exhibited no enhancement during 30 s continued scans. Conclusion: The blood supply of liver metastasis mainly comes from hepatic artery, but barely from portal vein. (authors)

  1. 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.

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

    Science.gov (United States)

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

    2014-08-01

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

  3. Thermal behavior of human eye in relation with change in blood perfusion, porosity, evaporation and ambient temperature.

    Science.gov (United States)

    Rafiq, Aasma; Khanday, M A

    2016-12-01

    Extreme environmental and physiological conditions present challenges for thermal processes in body tissues including multi-layered human eye. A mathematical model has been formulated in this direction to study the thermal behavior of the human eye in relation with the change in blood perfusion, porosity, evaporation and environmental temperatures. In this study, a comprehensive thermal analysis has been performed on the multi-layered eye using Pennes' bio-heat equation with appropriate boundary and interface conditions. The variational finite element method and MATLAB software were used for the solution purpose and simulation of the results. The thermoregulatory effect due to blood perfusion rate, porosity, ambient temperature and evaporation at various regions of human eye was illustrated mathematically and graphically. The main applications of this model are associated with the medical sciences while performing laser therapy and other thermoregulatory investigation on human eye. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Regional blood perfusion in childhood partial seizure using N-isopropyl-p-[I-123]iodoamphetamine and single photon emission CT

    International Nuclear Information System (INIS)

    Michihiro, Narumi; Kurosawa, Yumiko; Hibio, Shuichi; Ishihara, Hiroaki; Ariizumi, Motomizu

    1989-01-01

    Single photon emission CT (SPECT) with N-isopropyl-p-[I-123]iodoamphetamine was performed in 20 pediatric patients with partial seizure to examine regional blood perfusion. In detecting location of abnormality, SPECT and EEG were concordant in 13 patients (65%) and discordant in 4 patients (20%). In 7 patients undergoing SPECT one to 4 years after seizure onset, decreased blood perfusion corresponded to focal abnormality on EEG. In other 9 patiets in whom SPECT was performed within one year, however, location of abnormality on SPECT did not necessarily concur with that on EEG. These findings suggest that brain lesions are not focal but extensive at the early stage of partial seizure and that they are becoming focal with the mature of the central nervous system. (Namekawa, K)

  5. Quantitative assessment of magnetic resonance derived myocardial perfusion measurements using advanced techniques: microsphere validation in an explanted pig heart system.

    Science.gov (United States)

    Schuster, Andreas; Zarinabad, Niloufar; Ishida, Masaki; Sinclair, Matthew; van den Wijngaard, Jeroen Phm; Morton, Geraint; Hautvast, Gilion Ltf; Bigalke, Boris; van Horssen, Pepijn; Smith, Nicolas; Spaan, Jos Ae; Siebes, Maria; Chiribiri, Amedeo; Nagel, Eike

    2014-10-14

    Cardiovascular Magnetic Resonance (CMR) myocardial perfusion imaging has the potential to evolve into a method allowing full quantification of myocardial blood flow (MBF) in clinical routine. Multiple quantification pathways have been proposed. However at present it remains unclear which algorithm is the most accurate. An isolated perfused, magnetic resonance (MR) compatible pig heart model allows very accurate titration of MBF and in combination with high-resolution assessment of fluorescently-labeled microspheres represents a near optimal platform for validation. We sought to investigate which algorithm is most suited to quantify myocardial perfusion by CMR at 1.5 and 3 Tesla using state of the art CMR perfusion techniques and quantification algorithms. First-pass perfusion CMR was performed in an MR compatible blood perfused pig heart model. We acquired perfusion images at physiological flow ("rest"), reduced flow ("ischaemia") and during adenosine-induced hyperaemia ("hyperaemia") as well as during coronary occlusion. Perfusion CMR was performed at 1.5 Tesla (n = 4 animals) and at 3 Tesla (n = 4 animals). Fluorescently-labeled microspheres and externally controlled coronary blood flow served as reference standards for comparison of different quantification strategies, namely Fermi function deconvolution (Fermi), autoregressive moving average modelling (ARMA), exponential basis deconvolution (Exponential) and B-spline basis deconvolution (B-spline). All CMR derived MBF estimates significantly correlated with microsphere results. The best correlation was achieved with Fermi function deconvolution both at 1.5 Tesla (r = 0.93, p Tesla (r = 0.9, p Tesla (p Tesla and showed the weakest correlation to microspheres (r = 0.74, p Tesla exponential deconvolution performed worst (r = 0.49, p model. Amongst the different techniques, Fermi function deconvolution was the most accurate technique at both field strengths. Perfusion CMR based on Fermi

  6. Brief ex vivo perfusion with heparinized and/or citrated whole blood enhances tolerance of free muscle flaps to prolonged ischemia.

    Science.gov (United States)

    Fowler, J D; Li, X; Cooley, B C

    1999-01-01

    This study investigated the use of heparinized and/or citrated whole blood as a perfusate for enhancing muscle tolerance to warm ischemia. Unilateral cutaneous trunci muscle flaps were harvested from Sprague-Dawley rats and stored for 10 hr at 22-24 degrees C prior to transplantation to the groin. One group served as a non-perfused control. In three experimental groups, the flaps were hand-perfused ex vivo with 1.0 ml of heparinized, citrated, or heparinized and citrated autogenous whole blood at physiological pressures. Perfusion was administered over a 10-min period 5 hr into the ischemic period. Flaps were revascularized on the femoral vessels and then harvested 48 hr following revascularization. Tissue injury was assessed by calculation of flap weight change (indicator of tissue edema), histochemical evaluation of muscle dehydrogenase activity (nitroblue tetrazolium assay), and light microscopy. All perfused groups had significantly higher muscle dehydrogenase activity compared with non-perfused controls (P flap edema was seen in the combined heparin-citrate perfusion of flaps compared with nonperfused controls (P flaps. We conclude that mid-ischemic perfusion with heparinized and/or citrated blood limits the deleterious effects of extended warm ischemia.

  7. Measurement of extracellular volume and transit time heterogeneity using contrast-enhanced myocardial perfusion MRI in patients after acute myocardial infarction.

    Science.gov (United States)

    Kunze, Karl P; Rischpler, Christoph; Hayes, Carmel; Ibrahim, Tareq; Laugwitz, Karl-Ludwig; Haase, Axel; Schwaiger, Markus; Nekolla, Stephan G

    2017-06-01

    To assess the ability of dynamic contrast-enhanced myocardial perfusion MRI to measure extracellular volume (ECV) and to investigate the possibility of estimating capillary transit time heterogeneity (CTH) in patients after myocardial infarction and successful revascularization. Twenty-four perfusion data sets were acquired on a 3 Tesla positron emission tomography (PET)/MRI scanner. Three perfusion models of different complexity were implemented in a hierarchical fashion with an Akaike information criterion being used to determine the number of fit parameters supported by the data. Results were compared sector-wise to ECV from an equilibrium T 1 mapping method (modified look-locker inversion recovery (MOLLI)). ECV derived from the perfusion analysis correlated well with equilibrium measurements (R² = 0.76). Estimation of CTH was supported in 16% of sectors (mostly remote). Inclusion of a nonzero CTH parameter usually led to lower estimates of first-pass extraction and slightly higher estimates of blood volume and flow. Estimation of the capillary permeability-surface area product was feasible in 81% of sectors. Transit time heterogeneity has a measurable effect on the kinetic analysis of myocardial perfusion MRI data, and Gd-DTPA extravasation in the myocardium is usually not flow-limited in infarct-related pathology. Measurement of myocardial ECV using perfusion imaging could provide a scan-time efficient alternative to methods based on T 1 mapping. Magn Reson Med 77:2320-2330, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  8. [Realization of a measurement module for determining pH value in perfusion cultures].

    Science.gov (United States)

    Dencks, St; Hanke, G; Rabenau, M; Poll, R

    2002-01-01

    For cultivating animal cells in bioreactors the maintenance of a fixed pH-value is of elementary importance. In a perfused cell culture system the pH-value is measured by electrochemical flow rate sensors. For the acceptance of a technical solution the integration in complex workplaces is necessary, thereby small size and low costs are the main features. For that a special measurement module was developed, consisting of measuring amplifier and microcontroller component with CAN-Bus-interface.

  9. Influence of vascular enhancement, age and gender on pulmonary perfused blood volume quantified by dual-energy-CTPA

    International Nuclear Information System (INIS)

    Meinel, Felix G.; Graef, Anita; Sommer, Wieland H.; Thierfelder, Kolja M.; Reiser, Maximilian F.; Johnson, Thorsten R.C.

    2013-01-01

    Objectives: To determine the influence of technical and demographic parameters on quantification of pulmonary perfused blood volume (PBV) in dual energy computed tomography pulmonary angiography (DE-CTPA). Materials and methods: Pulmonary PBV was quantified in 142 patients who underwent DE-CTPA for suspected pulmonary embolism but in whom no thoracic pathologies were detected. Multivariate linear regression analysis was performed to calculate the influence of age, gender, enhancement of pulmonary trunk and enhancement difference between pulmonary trunk and left atrium (as a measure of timing) on PBV values. The resulting regression coefficients were used to calculate age-specific ranges of normal for PBV values adjusted for vascular enhancement and timing. Results: Enhancement of the pulmonary trunk (β = −0.29, p = 0.001) and enhancement difference between pulmonary trunk and left atrium (β = −0.24, p = 0.003) were found to significantly influence PBV values. Age (β = −0.33, p < 0.001) but not gender (β = 0.14, p = 0.05) had a significant negative influence on pulmonary PBV values. There was a 20% relative decrease of pulmonary PBV from patients aged <30 to patients over 80 years of age. Conclusions: DE-CTPA derived PBV values need to be corrected for age, vascular enhancement and timing but not for gender. The age-specific ranges of normal derived from this study can be used as a reference in future studies of PBV in pulmonary pathologies

  10. Improving cerebral blood flow quantification for arterial spin labeled perfusion MRI by removing residual motion artifacts and global signal fluctuations.

    Science.gov (United States)

    Wang, Ze

    2012-12-01

    Denoising is critical to improving the quality and stability of cerebral blood flow (CBF) quantification in arterial spin labeled (ASL) perfusion magnetic resonance imaging (MRI) due to the intrinsic low signal-to-noise-ratio (SNR) of ASL data. Previous studies have been focused on reducing the spatial or temporal noise using standard filtering techniques, and less attention has been paid to two global nuisance effects, the residual motion artifacts and the global signal fluctuations. Since both nuisances affect the whole brain, removing them in advance should enhance the CBF quantification quality for ASL MRI. The purpose of this paper was to assess this potential benefit. Three methods were proposed to suppress each or both of the two global nuisances. Their performances for CBF quantification were validated using ASL data acquired from 13 subjects. Evaluation results showed that covarying out both global nuisances significantly improved temporal SNR and test-retest stability of CBF measurement. Although the concept of removing both nuisances is not technically novel per se, this paper clearly showed the benefits for ASL CBF quantification. Dissemination of the proposed methods in a free ASL data processing toolbox should be of interest to a broad range of ASL users. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Long-Term Spinal Cord Stimulation Alleviates Mechanical Hypersensitivity and Increases Peripheral Cutaneous Blood Perfusion in Experimental Painful Diabetic Polyneuropathy.

    Science.gov (United States)

    van Beek, Maarten; Hermes, Denise; Honig, Wiel M; Linderoth, Bengt; van Kuijk, Sander M J; van Kleef, Maarten; Joosten, Elbert A

    2018-03-09

    This study utilizes a model of long-term spinal cord stimulation (SCS) in experimental painful diabetic polyneuropathy (PDPN) to investigate the behavioral response during and after four weeks of SCS (12 hours/day). Second, we investigated the effect of long-term SCS on peripheral cutaneous blood perfusion in experimental PDPN. Mechanical sensitivity was assessed in streptozotocin induced diabetic rats (n = 50) with von Frey analysis. Hypersensitive rats (n = 24) were implanted with an internal SCS battery, coupled to an SCS electrode covering spinal levels L2-L5. The effects of four weeks of daily conventional SCS for 12 hours (n = 12) or Sham SCS (n = 12) were evaluated with von Frey assessment, and laser Doppler imaging (LDI). Average paw withdrawal thresholds (PWT) increased during long-term SCS in the SCS group, in contrast to a decrease in the Sham group (Sham vs. SCS; p = 0.029). Twenty-four hours after long-term SCS average PWT remained higher in the SCS group. Furthermore, the SCS group showed a higher cutaneous blood perfusion during long-term SCS compared to the Sham group (Sham vs. SCS; p = 0.048). Forty-eight hours after long-term SCS, no differences in skin perfusion were observed. We demonstrated that long-term SCS results in decreased baseline mechanical hypersensitivity and results in increased peripheral blood perfusion during stimulation in a rat model of PDPN. Together, these findings indicate that long-term SCS results in modulation of the physiological circuitry related to the nociceptive system in addition to symptomatic treatment of painful symptoms. © 2018 The Authors. Neuromodulation: Technology at the Neural Interface published by Wiley Periodicals, Inc. on behalf of International Neuromodulation Society.

  12. Microheterogeneity of regional myocardial blood flows in low-perfused rat hearts evaluated by double-tracer digital radiography

    International Nuclear Information System (INIS)

    Matsumoto, Takeshi; Asano, Takahisa; Takemoto, Mami; Tachibana, Hiroyuki; Ogasawara, Yasuo; Kajiya, Fumihiko

    2007-01-01

    Using 3 H- and 125 I-labeled desmethylimipramine (DMI) for regional flow tracers, we established a two-time measurement method for the spatial pattern of myocardial perfusion in cross-circulated rat hearts. Myocardial extractions and retentions of these tracers were confirmed to be satisfactory; however, the latter were less than 90% after 3 min at a perfusion rate of 2.9 ml/min/g, limiting the present application to a short-time perfusion measurement. Distributions of myocardial depositions were separated by subtraction digital radiography with 400-μm pixel resolution. Its feasibility was examined by regression analysis between local deposition densities of 3 H- and 125 I-DMI injected simultaneously. The slope, y-intercept, and correlation coefficient (r) of the regression line were 0.98±0.04, 0.02±0.04, and 0.95±0.03, respectively, indicating the validity of the present image subtraction technique. The spatial pattern of myocardial perfusion in response to flow reduction was evaluated by the injections of 3 H- and 125 I-DMI, respectively, before and after a nearly 70% flow reduction. A significant correlation between normalized density distributions of these tracers was found in both subepicardium (r=0.77±0.12) and subendocardium (r=0.73±0.20), indicating the stable pattern of myocardial perfusion. However, the coefficient of variation of tracer densities showed a decrease of subendocardial flow heterogeneity from 35±15% to 31±16%. Thus, flow differences between originally high- and low-flow regions in subendocardium were reduced on a relative basis during low perfusion

  13. The feasibility and reliability of capillary blood pressure measurements in the fingernail fold

    NARCIS (Netherlands)

    de Graaff, Jurgen C.; Ubbink, Dirk Th; Lagarde, Sjoerd M.; Jacobs, Michael J. H. M.

    2002-01-01

    Capillary blood pressure is an essential parameter in the study of the (patho-)physiology of microvascular perfusion. Currently, capillary pressure measurements in humans are performed using a servo-nulling micropressure system containing an oil-water interface, which suffers some drawbacks. In

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

    Science.gov (United States)

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

    2011-03-01

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

  15. Effects of Electroacupuncture Stimulation at “Zusanli” Acupoint on Hepatic NO Release and Blood Perfusion in Mice

    Directory of Open Access Journals (Sweden)

    Shu-you Wang

    2015-01-01

    Full Text Available The study is to observe the influence of electroacupuncture (EA stimulation at “Zusanli” (ST36 on the release of nitric oxide (NO and blood perfusion (BP in the liver and further explore whether the hepatic blood perfusion (HBP changes were regulated by EA ST36 induced NO in nitric oxide synthase inhibited mice. The HBP change of the mice was detected by laser speckle perfusion imaging (LSPI before and after being given interventions, and the NO in liver tissue was detected by nitric acid reductase in each group. The NO levels and HBP in the L-NAME group were significantly lower than those in the control group (P<0.01. The NO level and HBP increase in EA group were significantly higher than those in control group (P<0.05. The NO level in the L-NAME EA group was slightly higher than that in the L-NAME group. The HBP increase in the L-NAME EA group was not statistically significant. These results showed that EA could accelerate the synthesis of NO and thereby increase HBP via vasodilation in liver tissue.

  16. Complement C3 inhibitor Cp40 attenuates xenoreactions in pig hearts perfused with human blood.

    Science.gov (United States)

    Abicht, Jan-Michael; Kourtzelis, Ioannis; Reichart, Bruno; Koutsogiannaki, Sophia; Primikyri, Alexandra; Lambris, John D; Chavakis, Triantafyllos; Holdt, Lesca; Kind, Alexander; Guethoff, Sonja; Mayr, Tanja

    2017-01-01

    The complement system plays a crucial role in acute xenogeneic reactions after cardiac transplantation. We used an ex vivo perfusion model to investigate the effect of Cp40, a compstatin analog and potent inhibitor of complement at the level of C3. Fifteen wild-type pig hearts were explanted, cardiopleged, and reperfused ex vivo after 150 minutes of cold ischemia. Hearts were challenged in a biventricular working heart mode to evaluate cardiac perfusion and function. In the treatment group (n=5), the complement cascade was blocked at the level of C3 using Cp40, using diluted human blood. Untreated human and porcine blood was used for controls. Throughout the perfusion, C3 activation was inhibited when Cp40 was used (mean of all time points: 1.11 ± 0.34% vs 3.12 ± 0.48% control activation; Phearts xenoperfused ex vivo. We suggest that this compstatin analog, which blocks all main pathways of complement activation, could be a beneficial perioperative treatment in preclinical and in future clinical xenotransplantation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Physiological and psychological individual differences influence resting brain function measured by ASL perfusion.

    Science.gov (United States)

    Kano, M; Coen, S J; Farmer, A D; Aziz, Q; Williams, S C R; Alsop, D C; Fukudo, S; O'Gorman, R L

    2014-09-01

    Effects of physiological and/or psychological inter-individual differences on the resting brain state have not been fully established. The present study investigated the effects of individual differences in basal autonomic tone and positive and negative personality dimensions on resting brain activity. Whole-brain resting cerebral perfusion images were acquired from 32 healthy subjects (16 males) using arterial spin labeling perfusion MRI. Neuroticism and extraversion were assessed with the Eysenck Personality Questionnaire-Revised. Resting autonomic activity was assessed using a validated measure of baseline cardiac vagal tone (CVT) in each individual. Potential associations between the perfusion data and individual CVT (27 subjects) and personality score (28 subjects) were tested at the level of voxel clusters by fitting a multiple regression model at each intracerebral voxel. Greater baseline perfusion in the dorsal anterior cingulate cortex (ACC) and cerebellum was associated with lower CVT. At a corrected significance threshold of p individual autonomic tone and psychological variability influence resting brain activity in brain regions, previously shown to be associated with autonomic arousal (dorsal ACC) and personality traits (amygdala, caudate, etc.) during active task processing. The resting brain state may therefore need to be taken into account when interpreting the neurobiology of individual differences in structural and functional brain activity.

  18. Deconvolution-Based CT and MR Brain Perfusion Measurement: Theoretical Model Revisited and Practical Implementation Details

    Science.gov (United States)

    Fieselmann, Andreas; Kowarschik, Markus; Ganguly, Arundhuti; Hornegger, Joachim; Fahrig, Rebecca

    2011-01-01

    Deconvolution-based analysis of CT and MR brain perfusion data is widely used in clinical practice and it is still a topic of ongoing research activities. In this paper, we present a comprehensive derivation and explanation of the underlying physiological model for intravascular tracer systems. We also discuss practical details that are needed to properly implement algorithms for perfusion analysis. Our description of the practical computer implementation is focused on the most frequently employed algebraic deconvolution methods based on the singular value decomposition. In particular, we further discuss the need for regularization in order to obtain physiologically reasonable results. We include an overview of relevant preprocessing steps and provide numerous references to the literature. We cover both CT and MR brain perfusion imaging in this paper because they share many common aspects. The combination of both the theoretical as well as the practical aspects of perfusion analysis explicitly emphasizes the simplifications to the underlying physiological model that are necessary in order to apply it to measured data acquired with current CT and MR scanners. PMID:21904538

  19. Deconvolution-Based CT and MR Brain Perfusion Measurement: Theoretical Model Revisited and Practical Implementation Details.

    Science.gov (United States)

    Fieselmann, Andreas; Kowarschik, Markus; Ganguly, Arundhuti; Hornegger, Joachim; Fahrig, Rebecca

    2011-01-01

    Deconvolution-based analysis of CT and MR brain perfusion data is widely used in clinical practice and it is still a topic of ongoing research activities. In this paper, we present a comprehensive derivation and explanation of the underlying physiological model for intravascular tracer systems. We also discuss practical details that are needed to properly implement algorithms for perfusion analysis. Our description of the practical computer implementation is focused on the most frequently employed algebraic deconvolution methods based on the singular value decomposition. In particular, we further discuss the need for regularization in order to obtain physiologically reasonable results. We include an overview of relevant preprocessing steps and provide numerous references to the literature. We cover both CT and MR brain perfusion imaging in this paper because they share many common aspects. The combination of both the theoretical as well as the practical aspects of perfusion analysis explicitly emphasizes the simplifications to the underlying physiological model that are necessary in order to apply it to measured data acquired with current CT and MR scanners.

  20. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    International Nuclear Information System (INIS)

    Mendrik, Adrienne M; Van Ginneken, Bram; Viergever, Max A; Vonken, Evert-jan; De Jong, Hugo W; Riordan, Alan; Van Seeters, Tom; Smit, Ewoud J; Prokop, Mathias

    2011-01-01

    Cerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of x-ray radiation that can be used per sequential scan is limited, which results in a high level of noise. To detect areas of abnormal perfusion, perfusion parameters are derived from the CTP data, such as the cerebral blood flow (CBF). Algorithms to determine perfusion parameters, especially singular value decomposition, are very sensitive to noise. Therefore, noise reduction is an important preprocessing step for CTP analysis. In this paper, we propose a time-intensity profile similarity (TIPS) bilateral filter to reduce noise in 4D CTP scans, while preserving the time-intensity profiles (fourth dimension) that are essential for determining the perfusion parameters. The proposed TIPS bilateral filter is compared to standard Gaussian filtering, and 4D and 3D (applied separately to each sequential scan) bilateral filtering on both phantom and patient data. Results on the phantom data show that the TIPS bilateral filter is best able to approach the ground truth (noise-free phantom), compared to the other filtering methods (lowest root mean square error). An observer study is performed using CBF maps derived from fifteen CTP scans of acute stroke patients filtered with standard Gaussian, 3D, 4D and TIPS bilateral filtering. These CBF maps were blindly presented to two observers that indicated which map they preferred for (1) gray/white matter differentiation, (2) detectability of infarcted area and (3) overall image quality. Based on these results, the TIPS bilateral filter ranked best and its CBF maps were scored to have the best overall image quality in 100% of the cases by both observers. Furthermore, quantitative CBF and cerebral blood volume values in both the phantom and the

  1. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    Energy Technology Data Exchange (ETDEWEB)

    Mendrik, Adrienne M; Van Ginneken, Bram; Viergever, Max A [Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Vonken, Evert-jan; De Jong, Hugo W; Riordan, Alan; Van Seeters, Tom; Smit, Ewoud J; Prokop, Mathias, E-mail: a.m.mendrik@gmail.com [Radiology Department, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)

    2011-07-07

    Cerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of x-ray radiation that can be used per sequential scan is limited, which results in a high level of noise. To detect areas of abnormal perfusion, perfusion parameters are derived from the CTP data, such as the cerebral blood flow (CBF). Algorithms to determine perfusion parameters, especially singular value decomposition, are very sensitive to noise. Therefore, noise reduction is an important preprocessing step for CTP analysis. In this paper, we propose a time-intensity profile similarity (TIPS) bilateral filter to reduce noise in 4D CTP scans, while preserving the time-intensity profiles (fourth dimension) that are essential for determining the perfusion parameters. The proposed TIPS bilateral filter is compared to standard Gaussian filtering, and 4D and 3D (applied separately to each sequential scan) bilateral filtering on both phantom and patient data. Results on the phantom data show that the TIPS bilateral filter is best able to approach the ground truth (noise-free phantom), compared to the other filtering methods (lowest root mean square error). An observer study is performed using CBF maps derived from fifteen CTP scans of acute stroke patients filtered with standard Gaussian, 3D, 4D and TIPS bilateral filtering. These CBF maps were blindly presented to two observers that indicated which map they preferred for (1) gray/white matter differentiation, (2) detectability of infarcted area and (3) overall image quality. Based on these results, the TIPS bilateral filter ranked best and its CBF maps were scored to have the best overall image quality in 100% of the cases by both observers. Furthermore, quantitative CBF and cerebral blood volume values in both the phantom and the

  2. Paradox: increased blood perfusion to the face enhances protection against frostbite while it lowers wind chill equivalent temperatures.

    Science.gov (United States)

    Shitzer, Avraham

    2007-05-01

    A model of facial heat exchange in cold and windy environments is presented. The tissue is depicted as a hollow cylinder and the model includes heat conduction and heat transport by blood circulation from the warmer core. A steady-state solution facilitating the estimation of wind chill equivalent temperature (WCET) as a function of the effective wind velocity, air temperature and blood perfusion rate was obtained. The results quantify and demonstrate the elevation of skin temperatures caused by increased flow of warmer blood from the inner core to the face. Elevated facial temperatures, while enhancing protection against frostbite and other cold-related injuries, also increase heat loss to the colder environment. Paradoxically, such elevated facial temperatures cause WCETs, as estimated by the prevailing definition, to attain lower rather than higher values, indicating, in fact, increased risk of frostbite. The results of this study should be useful in understanding and quantifying the effects of blood perfusion in protection against cold-related injuries. They should also be considered in the re-evaluation and re-formulation of the concept of wind chill, which has been a useful cold weather indicator for decades.

  3. Role of perfusion SPECT in prediction and measurement of pulmonary complications after radiotherapy for lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Farr, Katherina P.; Khalil, Azza A.; Grau, Cai [Aarhus University Hospital, Department of Oncology, Aarhus C (Denmark); Kramer, Stine; Morsing, Anni [Aarhus University Hospital, Department of Nuclear Medicine and PET Centre, Aarhus C (Denmark)

    2015-07-15

    The purpose of the study was to evaluate the ability of baseline perfusion defect score (DS) on SPECT to predict the development of severe symptomatic radiation pneumonitis (RP) and to evaluate changes in perfusion on SPECT as a method of lung perfusion function assessment after curative radiotherapy (RT) for non-small-cell lung cancer (NSCLC). Patients with NSCLC undergoing curative RT were included prospectively. Perfusion SPECT/CT and global pulmonary function tests (PFT) were performed before RT and four times during follow-up. Functional activity on SPECT was measured using a semiquantitative perfusion DS. Pulmonary morbidity was graded by the National Cancer Institute's Common Terminology Criteria for Adverse Events version 4 for pneumonitis. Patients were divided into two groups according to the severity of RP. A total of 71 consecutive patients were included in the study. Baseline DS was associated with chronic obstructive pulmonary disease. A significant inverse correlation was found between baseline DS and forced expiratory volume in 1 s and diffusing capacity of the lung for carbon monoxide. Patients with severe RP had significantly higher baseline total lung DS (mean 5.43) than those with no or mild symptoms (mean DS 3.96, p < 0.01). PFT results were not different between these two groups. The odds ratio for total lung DS was 7.8 (95 % CI 1.9 - 31) demonstrating the ability of this parameter to predict severe RP. Adjustment for other potential confounders known to be associated with increased risk of RP was performed and did not change the odds ratio. The median follow-up time after RT was 8.4 months. The largest DS increase of 13.3 % was associated with severe RP at 3 months of follow-up (p < 0.01). The development of severe RP during follow-up was not associated with changes in PFT results. Perfusion SPECT is a valuable method for predicting severe RP and for assessing changes in regional functional perfusion after curative RT comparable with

  4. 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)

  5. Novel adhesive glove device (AGD) for active compression-decompression (ACD) CPR results in improved carotid blood flow and coronary perfusion pressure in piglet model of cardiac arrest.

    Science.gov (United States)

    Udassi, Jai P; Udassi, Sharda; Shih, Andre; Lamb, Melissa A; Porvasnik, Stacy L; Zaritsky, Arno L; Haque, Ikram U

    2012-06-01

    ACD-CPR improves coronary and cerebral perfusion. We developed an adhesive glove device (AGD) and hypothesized that ACD-CPR using an AGD provides better chest decompression resulting in improved carotid blood flow as compared to standard (S)-CPR. Prospective, randomized and controlled animal study. Sixteen anesthetized and ventilated piglets were randomized after 3 min of untreated VF to receive either S-CPR or AGD-ACD-CPR by a PALS certified single rescuer with compressions of 100 min(-1) and C:V ratio of 30:2. AGD consisted of a modified leather glove exposing the fingers and thumb. A wide Velcro patch was sewn to the palmer aspect of the glove and the counter Velcro patch was adhered to the pig's chest wall. Carotid blood flow was measured using ultrasound. Data (mean±SD) was analyzed using one way ANOVA and unpaired t-test; p-value ≤ 0.05 was considered statistically significant. Right atrial pressure (mmHg) during the decompression phase was lower during AGD-ACD-CPR (-3.32±2.0) when compared to S-CPR (0.86±1.8, p=0.0007). Mean carotid blood flow was 53.2±27.1 (% of baseline blood flow in ml/min) in AGD vs. 19.1±12.5% in S-CPR, p=0.006. Coronary perfusion pressure (CPP, mmHg) was 29.9±5.8 in AGD vs. 22.7±6.9 in S-CPR, p=0.04. There was no significant difference in time to ROSC and number of epinephrine doses. Active chest decompression during CPR using this simple and inexpensive adhesive glove device resulted in significantly better carotid blood flow during the first 2 min of CPR. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  6. Arterial spin labeling MR imaging reproducibly measures peak-exercise calf muscle perfusion: a study in patients with peripheral arterial disease and healthy volunteers.

    Science.gov (United States)

    Pollak, Amy W; Meyer, Craig H; Epstein, Frederick H; Jiji, Ronny S; Hunter, Jennifer R; Dimaria, Joseph M; Christopher, John M; Kramer, Christopher M

    2012-12-01

    This study hypothesized that arterial spin labeling (ASL) magnetic resonance (MR) imaging at 3-T would be a reliable noncontrast technique for measuring peak exercise calf muscle blood flow in both healthy volunteers and patients with peripheral arterial disease (PAD) and will discriminate between these groups. Prior work demonstrated the utility of first-pass gadolinium-enhanced calf muscle perfusion MR imaging in patients with PAD. However, patients with PAD often have advanced renal disease and cannot receive gadolinium. PAD patients had claudication and an ankle brachial index of 0.4 to 0.9. Age-matched normal subjects (NL) had no PAD risk factors and were symptom-free with exercise. All performed supine plantar flexion exercise in a 3-T MR imaging scanner using a pedal ergometer until exhaustion or limiting symptoms and were imaged at peak exercise with 15 averaged ASL images. Peak perfusion was measured from ASL blood flow images by placing a region of interest in the calf muscle region with the greatest signal intensity. Perfusion was compared between PAD patients and NL and repeat testing was performed in 12 subjects (5 NL, 7 PAD) for assessment of reproducibility. Peak exercise calf perfusion of 15 NL (age: 54 ± 9 years) was higher than in 15 PAD patients (age: 64 ± 5 years, ankle brachial index: 0.70 ± 0.14) (80 ± 23 ml/min - 100 g vs. 49 ± 16 ml/min/100 g, p calf muscle. Independent of exercise time, ASL discriminates between NL and PAD patients. This technique may prove useful for clinical trials of therapies for improving muscle perfusion, especially in patients unable to receive gadolinium. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  7. Comparison of blood flow models and acquisitions for quantitative myocardial perfusion estimation from dynamic CT.

    Science.gov (United States)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R; La Riviere, Patrick J; Alessio, Adam M

    2014-04-07

    Myocardial blood flow (MBF) can be estimated from dynamic contrast enhanced (DCE) cardiac CT acquisitions, leading to quantitative assessment of regional perfusion. The need for low radiation dose and the lack of consensus on MBF estimation methods motivates this study to refine the selection of acquisition protocols and models for CT-derived MBF. DCE cardiac CT acquisitions were simulated for a range of flow states (MBF = 0.5, 1, 2, 3 ml (min g)(-1), cardiac output = 3, 5, 8 L min(-1)). Patient kinetics were generated by a mathematical model of iodine exchange incorporating numerous physiological features including heterogenenous microvascular flow, permeability and capillary contrast gradients. CT acquisitions were simulated for multiple realizations of realistic x-ray flux levels. CT acquisitions that reduce radiation exposure were implemented by varying both temporal sampling (1, 2, and 3 s sampling intervals) and tube currents (140, 70, and 25 mAs). For all acquisitions, we compared three quantitative MBF estimation methods (two-compartment model, an axially-distributed model, and the adiabatic approximation to the tissue homogeneous model) and a qualitative slope-based method. In total, over 11 000 time attenuation curves were used to evaluate MBF estimation in multiple patient and imaging scenarios. After iodine-based beam hardening correction, the slope method consistently underestimated flow by on average 47.5% and the quantitative models provided estimates with less than 6.5% average bias and increasing variance with increasing dose reductions. The three quantitative models performed equally well, offering estimates with essentially identical root mean squared error (RMSE) for matched acquisitions. MBF estimates using the qualitative slope method were inferior in terms of bias and RMSE compared to the quantitative methods. MBF estimate error was equal at matched dose reductions for all quantitative methods and range of techniques evaluated. This

  8. Comparison of blood flow models and acquisitions for quantitative myocardial perfusion estimation from dynamic CT

    Science.gov (United States)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2014-04-01

    Myocardial blood flow (MBF) can be estimated from dynamic contrast enhanced (DCE) cardiac CT acquisitions, leading to quantitative assessment of regional perfusion. The need for low radiation dose and the lack of consensus on MBF estimation methods motivates this study to refine the selection of acquisition protocols and models for CT-derived MBF. DCE cardiac CT acquisitions were simulated for a range of flow states (MBF = 0.5, 1, 2, 3 ml (min g)-1, cardiac output = 3, 5, 8 L min-1). Patient kinetics were generated by a mathematical model of iodine exchange incorporating numerous physiological features including heterogenenous microvascular flow, permeability and capillary contrast gradients. CT acquisitions were simulated for multiple realizations of realistic x-ray flux levels. CT acquisitions that reduce radiation exposure were implemented by varying both temporal sampling (1, 2, and 3 s sampling intervals) and tube currents (140, 70, and 25 mAs). For all acquisitions, we compared three quantitative MBF estimation methods (two-compartment model, an axially-distributed model, and the adiabatic approximation to the tissue homogeneous model) and a qualitative slope-based method. In total, over 11 000 time attenuation curves were used to evaluate MBF estimation in multiple patient and imaging scenarios. After iodine-based beam hardening correction, the slope method consistently underestimated flow by on average 47.5% and the quantitative models provided estimates with less than 6.5% average bias and increasing variance with increasing dose reductions. The three quantitative models performed equally well, offering estimates with essentially identical root mean squared error (RMSE) for matched acquisitions. MBF estimates using the qualitative slope method were inferior in terms of bias and RMSE compared to the quantitative methods. MBF estimate error was equal at matched dose reductions for all quantitative methods and range of techniques evaluated. This suggests that

  9. Measurement of pulmonary vascular resistance of Fontan candidates with pulmonary arterial distortion by means of pulmonary perfusion imaging

    International Nuclear Information System (INIS)

    Park, In-Sam; Mizukami, Ayumi; Tomimatsu, Hirofumi; Kondou, Chisato; Nakanishi, Toshio; Nakazawa, Makoto; Momma, Kazuo

    1998-01-01

    We measured the distribution of blood flow to the right (R) and left lung (L) by means of pulmonary perfusion imaging and calculated pulmonary vascular resistance (Rp) in 13 patients, whose right and left pulmonary artery pressures were different by 2 to 9 mmHg due to pulmonary arterial distortion (5 interruption, 8 stenosis). The right lung/left lung blood flow ratio was determined and from the ratio and the total pulmonary blood flow, which was determined using the Fick's principle, the absolute values of right and left pulmonary blood flow were calculated. Using the right and left pulmonary blood flow and the right and left pulmonary arterial pressures, right and left pulmonary vascular resistance were calculated, separately. Vascular resistance of the whole lung (Rp) was then calculated using the following equation. 1/(Rp of total lung)=1/(Rp of right lung)+1/(Rp of left lung). Rp calculated from this equation was 1.8+/-0.8 U·m 2 and all values were less than 3 U·m 2 (range 0.3-2.8). Rp estimated from the conventional method using the total pulmonary blood flow and pulmonary arterial pressures, without using the right/left blood flow ratio, ranging from 0.4 to 3.8 U·m 2 and 5 of 13 patients showed Rp>3 U·m 2 . All patients underwent Fontan operation successfully. These data indicated that this method is useful to estimate Rp and to determine the indication of Fontan operation in patients with pulmonary arterial distortions. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

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

  11. Microstructure oriented modelling of hierarchically perfused porous media for cerebral blood flow evaluation

    Czech Academy of Sciences Publication Activity Database

    Tonar, Z.; Kochová, P.; Cimrman, R.; Witter, K.; Janáček, Jiří; Rohan, V.

    2011-01-01

    Roč. 465, č. 2011 (2011), s. 286-289 ISSN 1013-9826. [International Conference on Materials Structure & Micromechanics of Fracture /6./. Brno, 28.06.2010-30.06.2010] Institutional research plan: CEZ:AV0Z50110509 Keywords : brain * perfusion * morphometry * microvessels * stereology * modelling Subject RIV: EA - Cell Biology

  12. Blood perfusion in osteomyelitis studied with [O-15] water PET in a juvenile porcine model

    DEFF Research Database (Denmark)

    Jodal, Lars; Nielsen, Ole L.; Afzelius, Pia

    2017-01-01

    Background Osteomyelitis is a serious disease which can be difficult to treat despite properly instituted antibiotic therapy. This appears to be related at least partly to degraded vascularisation in the osteomyelitic (OM) lesions. Studies of perfusion in OM bones are, however, few and not quanti...

  13. 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

  14. Measurement of myocardial perfusion with electron beam tomography: comparison with {sup 99m}Tc-MIBI scan

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Koo; Choi, Jin Young; Yoo, Seok Jong [Research Institute of Radiological Science, Seoul (Korea, Republic of); And Others

    2000-07-01

    To compare the accuracy with which electron beam tomography (EBT) and {sup 99m}Tc-MIBI scanning measure myocardial perfusion valve. Twenty-two subjects (normal volunteers (n=3D6), patients in whom ischemic heart disease was diagnosed (n=3D5), and those in whom ischemic heart disease was suspected but who were found to be normal (n=3D11)) were involved in this study. EBT was performed after bolus injection of contrast media (50 ml of Iopamiro 370 or Optiray 350, 3 ml/sec). The myocardium was divided into 16 segments according to the classification devised by the American Society of Echocardiography, and each myocardial perfusion value was calculated by post-image processing. A pharmacologic stress test was performed in all subjects except four patients with acute myocardial infarction, and myocardial perfusion reserve ratios were assessed. Single photon emission computed tomography (SPECT) was performed after the injection of 20 mCi of {sup 99m}Tc-MIBI. Any segment with moderate to severe photon defect on visual analysis of SPECT were identified and perfusion values determined by EBT in normal and ischemic segments were compared. No difference in myocardial perfusion was found between volunteers and the suspected group. Their perfusion values were 0.71{+-}0.14 ml/g/min in the resting state and 1.16{+-}0.24 ml/g/min on the stress test and the myocardial perfusion reserve ratio was, therefore, 1:1.68{+-}0.38. In ischemic patients, {sup 99m}Tc-MIBI scanning revealed a perfusion defect in 28 segments, and on EBT the measurement obtained was 0.54{+-}0.19 ml/g/min. The remaining 324 perfusion segments shown by SPECT to be normal showed a perfusion value of 0.79{+-}0.22 ml/g/min on EBT. Compared with {sup 99m}Tc-MIBI scanning, the measurement of myocardial perfusion by EBT provides absolute quantification of perfusion value and more detailed anatomic information. (author)

  15. 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.

  16. 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

  17. Silencing of eIF3e promotes blood perfusion recovery after limb ischemia through stabilization of hypoxia-inducible factor 2α activity.

    Science.gov (United States)

    Hashimoto, Takuya; Chen, Li; Kimura, Hideo; Endler, Alexander; Koyama, Hiroyuki; Miyata, Tetsuro; Shibasaki, Futoshi; Watanabe, Toshiaki

    2016-07-01

    We previously observed that silencing of eukaryotic translation initiation factor 3 subunit e (eIF3e), a hypoxia-independent downregulator of hypoxia-inducible factor 2α (HIF-2α), led to neoangiogenesis by promoting HIF-2α activity under normoxic conditions. In the current study, we investigated whether temporary silencing of eIF3e in muscles affects blood flow recovery in a mouse ischemic limb model. eIF3e silencing was performed using small interfering RNA (siRNA), and changes in gene transcription and protein expression were analyzed in vitro using murine primary skeletal muscle myoblast and human primary skeletal muscle myoblast cell cultures. In unilateral femoral artery ligation experiments, eIF3e siRNA-expressing plasmids were injected into the muscles of BALB/c mice near the ligation sites, and tissue damage and loss of limb function were scored for 28 days while serial measurements of limb perfusions were performed with laser Doppler perfusion imaging. Silencing of eIF3e in murine primary skeletal muscle myoblasts led to stabilization of HIF-2α and upregulation of angiogenic transcripts, including basic fibroblast growth factor and platelet-derived growth factor B (P recovery at days 7, 14, and 21 (P < .05). eIF3e is an angiogenesis suppressor and may be a therapeutic target for promoting angiogenesis after ischemic injuries. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  18. Effects of Combined Far-Infrared Radiation and Acupuncture at ST36 on Peripheral Blood Perfusion and Autonomic Activities

    Directory of Open Access Journals (Sweden)

    Cheng-Chan Yang

    2017-01-01

    Full Text Available Using four-channel photoplethysmography (PPG for acquiring peripheral arterial waveforms, this study investigated vascular and autonomic impacts of combined acupuncture-far infrared radiation (FIR in improving peripheral circulation. Twenty healthy young adults aged 25.5±4.6 were enrolled for 30-minute measurement. Each subject underwent four treatment strategies, including acupuncture at ST36 (Zusanli, pseudoacupuncture, FIR, and combined acupuncture-FIR at different time points. Response was assessed at 5-minute intervals. Area under arterial waveform at baseline was defined as AreaBaseline, whereas AreaStim referred to area at each 5-minute substage during and after treatment. AreaStim/AreaBaseline was compared at different stages and among different strategies. Autonomic activity at different stages was assessed using low-to-high frequency power ratio (LHR. The results demonstrated increased perfusion for each therapeutic strategy from stage 1 to stage 2 (all p<0.02. Elevated perfusion was noted for all treatment strategies at stage 3 compared to stage 1 except pseudoacupuncture. Increased LHR was noted only in subjects undergoing pseudoacupuncture at stage 3 compared to stage 1 (p=0.045. Reduced LHR at stage 2 compared to stage 1 was found only in combined treatment group (p=0.041. In conclusion, the results support clinical benefits of combined acupuncture-FIR treatment in enhancing peripheral perfusion and parasympathetic activity.

  19. Diagnostic examination performance by using microvascular leakage, cerebral blood volume, and blood flow derived from 3-T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in the differentiation of glioblastoma multiforme and brain metastasis

    International Nuclear Information System (INIS)

    Server, Andres; Nakstad, Per H.; Orheim, Tone E.D.; Graff, Bjoern A.; Josefsen, Roger; Kumar, Theresa

    2011-01-01

    Conventional magnetic resonance (MR) imaging has limited capacity to differentiate between glioblastoma multiforme (GBM) and metastasis. The purposes of this study were: (1) to compare microvascular leakage (MVL), cerebral blood volume (CBV), and blood flow (CBF) in the distinction of metastasis from GBM using dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC-MRI), and (2) to estimate the diagnostic accuracy of perfusion and permeability MR imaging. A prospective study of 61 patients (40 GBMs and 21 metastases) was performed at 3 T using DSC-MRI. Normalized rCBV and rCBF from tumoral (rCBVt, rCBFt), peri-enhancing region (rCBVe, rCBFe), and by dividing the value in the tumor by the value in the peri-enhancing region (rCBVt/e, rCBFt/e), as well as MVL were calculated. Hemodynamic and histopathologic variables were analyzed statistically and Spearman/Pearson correlations. Receiver operating characteristic curve analysis was performed for each of the variables. The rCBVe, rCBFe, and MVL were significantly greater in GBMs compared with those of metastases. The optimal cutoff value for differentiating GBM from metastasis was 0.80 which implies a sensitivity of 95%, a specificity of 92%, a positive predictive value of 86%, and a negative predictive value of 97% for rCBVe ratio. We found a modest correlation between rCBVt and rCBFt ratios. MVL measurements in GBMs are significantly higher than those in metastases. Statistically, both rCBVe, rCBVt/e and rCBFe, rCBFt/e were useful in differentiating between GBMs and metastases, supporting the hypothesis that perfusion MR imaging can detect infiltration of tumor cells in the peri-enhancing region. (orig.)

  20. Lung perfusion measured using magnetic resonance imaging: New tools for physiological insights into the pulmonary circulation.

    Science.gov (United States)

    Hopkins, Susan R; Prisk, G Kim

    2010-12-01

    Since the lung receives the entire cardiac output, sophisticated imaging techniques are not required in order to measure total organ perfusion. However, for many years studying lung function has required physiologists to consider the lung as a single entity: in imaging terms as a single voxel. Since imaging, and in particular functional imaging, allows the acquisition of spatial information important for studying lung function, these techniques provide considerable promise and are of great interest for pulmonary physiologists. In particular, despite the challenges of low proton density and short T2* in the lung, noncontrast MRI techniques to measure pulmonary perfusion have several advantages including high reliability and the ability to make repeated measurements under a number of physiologic conditions. This brief review focuses on the application of a particular arterial spin labeling (ASL) technique, ASL-FAIRER (flow sensitive inversion recovery with an extra radiofrequency pulse), to answer physiologic questions related to pulmonary function in health and disease. The associated measurement of regional proton density to correct for gravitational-based lung deformation (the "Slinky" effect (Slinky is a registered trademark of Pauf-Slinky incorporated)) and issues related to absolute quantification are also discussed. Copyright © 2010 Wiley-Liss, Inc.

  1. Quantification of the effect of water exchange in dynamic contrast MRI perfusion measurements in the brain and heart

    DEFF Research Database (Denmark)

    Larsson, H B; Rosenbaum, S; Fritz-Hansen, T

    2001-01-01

    Measurement of myocardial and brain perfusion when using exogenous contrast agents (CAs) such as gadolinium-DTPA (Gd-DTPA) and MRI is affected by the diffusion of water between compartments. This water exchange may have an impact on signal enhancement, or, equivalently, on the longitudinal......(i)) by using a realistic simulation. These results were verified by in vivo studies of the heart and brain in humans. The conclusion is that water exchange between the vascular and extravascular extracellular space has no effect on K(i) estimation in the myocardium when a normal dose of Gd-DTPA is used. Water...... relaxation rate, and could therefore cause a systematic error in the calculation of perfusion (F) or the perfusion-related parameter, the unidirectional influx constant over the capillary membranes (K(i)). The aim of this study was to quantify the effect of water exchange on estimated perfusion (F or K...

  2. Assessment of myocardial perfusion abnormality and hibernating myocardium by gated blood pool and exercise-stress thallium tomographies after successful coronary angioplasty

    International Nuclear Information System (INIS)

    Hashimoto, Akiyoshi; Nakata, Tomoaki; Tsuchihashi, Kazufumi

    1993-01-01

    Cardiac function and myocardial perfusion were assessed by exercise-stress thallium SPECT and resting gated blood pool SPECT techniques before and after 47 successful coronary angioplasties. Thallium perfusion was analyzed visually and quantitatively in stress and resting studies. Left ventricular ejection fraction (LVEF) and peak filling rate (PFR) were calculated and regional wall motion was scored by amplitude and phase images in radionuclide planar and tomographic imagings. The thallium redistribution in delayed or resting SPECTs was more sensitive (87%) for detecting myocardial ischemia compared to symptoms (36%) and ECG changes (60%). An exercise capacity, LVEF, PFR, and the scores of perfusion and regional wall motion were improved significantly after coronary angioplasty. Stress thallium and gated blood pool SPECTs showed the improvements of myocardial perfusion in 159 (79%) of 201 segments and regional wall motion in 47 (51%) of 92 segments, respectively. These results suggest that the combined use of stress thallium SPECT, gated blood pool planar and SPECT techniques can contribute not only to the assessment of the efficacy of coronary angioplasty but also to detecting the mismatching of myocardial perfusion and contraction ('myocardial hibernation') in infarct-related myocardial lesions. (author)

  3. Acetazolamide tomoscintigraphic study of the effect on cerebral blood perfusion using 123I isopropyliodoamphetamine (IAMP 123I). Preliminary results

    International Nuclear Information System (INIS)

    Moretti, J.L.; Defer, G.; Delmon, L.; Caillat-Vigneron, N.; Devinoy, A.; Sergent, A.; Safai, N.; Cesaro, P.

    1987-01-01

    The effect of Acetazolamide (Diamox) on cerebral blood perfusion has been studied in ten patients with cerebral ischemia. Previously, the dose and time effects was tested in two independent groups of male Wistar rats. The cerebral blood perfusion was estimated in man by the cerebral distribution of Isopropyliodoamphetamine 123 I (IAMP 123 I) visualised with conventional emission tomography. The study involved two identical examinations, the second one followed an injection of 1 g of Diamox. The biodistribution of IAMP 123 I was studied in rats without or after different doses of Diamox by counting of target organs. In animals, the pulmonary activity curve versus the dose showed a maximum for 100 mg/kg as the cerebral activity curve increased proportional to the dose. The study of time effect indicated that the best conditions for cerebral imaging by IAMP 123 I seems to take place twenty minutes after the injection of Diamox. In man, the results obtained after Diamox confirmed the known effect of decreasing of vascular resistance, especially in brain. The total cerebral activity in IAMP 123 I was increased in all the patients. In six patients of the ten, the activity of the ischemic region was lower than expected because of the high uptake of the controlateral hemisphere. This phenomenon may increase the sensitivity of detecting lightly hypoperfused cerebral regions. In some other patients, a high activity of the ischemic zone seems to proove an early regulation of the regional blood flow and may be an element of good pronostic. Making an Acetazolamide injection before a tomoscintigraphic examination of the brain with IAMP 123 I seems to provide conventional imaging with sensitivity and pronostic value [fr

  4. Effects of topical hypotensive drugs on circadian IOP, blood pressure, and calculated diastolic ocular perfusion pressure in patients with glaucoma.

    Science.gov (United States)

    Quaranta, Luciano; Gandolfo, Federico; Turano, Raffaele; Rovida, Federico; Pizzolante, Teodoro; Musig, Andrea; Gandolfo, Enrico

    2006-07-01

    To compare the short-term effects of timolol 0.5%, brimonidine 0.2%, dorzolamide 2%, and latanoprost 0.005% on intraocular pressure (IOP), blood pressure (BP), and diastolic ocular perfusion pressure (DOPP), calculated as the difference between the diastolic blood pressure (DBP) and IOP. According to a 4 x 4 Latin squares design for repeated measures, 27 untreated patients and patients with newly diagnosed primary open-angle glaucoma (POAG) were treated with timolol 0.5% at 8 AM and 8 PM; brimonidine 0.2% at 8 AM and 8 PM; dorzolamide 2% at 8 AM, 2 PM, and 8 PM; and latanoprost 0.005% at 8 PM. The duration of each treatment course was 6-weeks, with a 4-week washout between each treatment. IOP and BP were measured at baseline and at the end of each treatment period. IOP was measured every 2 hours throughout a 24-hour period. Sitting IOP was measured from 8 AM to 10 PM by Goldmann applanation tonometry. Supine IOP was assessed from 12 to 6 AM by means of a handheld electronic tonometer (TonoPen XL; Mentor, Norwell, MA). BP monitoring was performed by means of an automated portable device (TM-2430; A & D Co., Saitama, Japan). All the drugs tested decreased the IOP significantly at all time points in comparison with baseline pressure. The mean 24-hour IOP after latanoprost administration (16.62+/-0.98 mm Hg) was significantly lower than that after timolol, brimonidine, or dorzolamide (P=0.0001). During the 24-hour period, brimonidine induced a significant decrease in systolic BP (SBP) and DBP at all time points when compared with baseline measurements and with those after administration of the other drugs (P<0.0001). Timolol caused a significant decrease in DBP and SBP at all the 24-hour time points when compared with the baseline and with the dorzolamide- and latanoprost-induced changes (P<0.0001). The mean 24-hour DOPPs were 50.7+/-5.9 mm Hg at baseline, 53+/-5.5 mm Hg with timolol, 46.2+/-5.4 mm Hg with brimonidine, 55.9+/-4.6 mm Hg with dorzolamide, and 56

  5. Comparison of spectroscopically measured finger and forearm tissue ethanol concentration to blood and breath ethanol measurements

    Science.gov (United States)

    Ridder, Trent D.; Hull, Edward L.; Ver Steeg, Benjamin J.; Laaksonen, Bentley D.

    2011-02-01

    Previous works investigated a spectroscopic technique that offered a promising alternative to blood and breath assays for determining in vivo alcohol concentration. Although these prior works measured the dorsal forearm, we report the results of a 26-subject clinical study designed to evaluate the spectroscopic technique at a finger measurement site through comparison to contemporaneous forearm spectroscopic, venous blood, and breath measurements. Through both Monte Carlo simulation and experimental data, it is shown that tissue optical probe design has a substantial impact on the effective path-length of photons through the skin and the signal-to-noise ratio of the spectroscopic measurements. Comparison of the breath, blood, and tissue assays demonstrated significant differences in alcohol concentration that are attributable to both assay accuracy and alcohol pharmacokinetics. Similar to past works, a first order kinetic model is used to estimate the fraction of concentration variance explained by alcohol pharmacokinetics (72.6-86.7%). A significant outcome of this work was significantly improved pharmacokinetic agreement with breath (arterial) alcohol of the finger measurement (mean kArt-Fin = 0.111 min-1) relative to the forearm measurement (mean kArt-For = 0.019 min-1) that is likely due to the increased blood perfusion of the finger.

  6. Quantification of MRI measured myocardial perfusion reserve in healthy humans: A comparison with positron emission tomography

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Hove, J.D.; Kofoed, K.F.

    2008-01-01

    Purpose: To validate a noninvasive quantitative MRI technique, the K-i perfusion method, for myocardial perfusion in humans using N-13-ammonia PET as a reference method. Materials and Methods: Ten healthy males (64 +/- 8 years) were examined with combined PET and MRI perfusion imaging at rest and...

  7. Role of perfusion SPECT in prediction and measurement of pulmonary complications after radiotherapy for lung cancer

    DEFF Research Database (Denmark)

    Farr, Katherina P; Kramer, Stine; Khalil, Azza A

    2015-01-01

    PURPOSE: The purpose of the study was to evaluate the ability of baseline perfusion defect score (DS) on SPECT to predict the development of severe symptomatic radiation pneumonitis (RP) and to evaluate changes in perfusion on SPECT as a method of lung perfusion function assessment after curative...

  8. Measurement of lung volume by lung perfusion scanning using SPECT and prediction of postoperative respiratory function

    International Nuclear Information System (INIS)

    Andou, Akio; Shimizu, Nobuyosi; Maruyama, Shuichiro

    1992-01-01

    Measurement of lung volume by lung perfusion scanning using single photon emission computed tomography (SPECT) and its usefulness for the prediction of respiratory function after lung resection were investigated. The lung volumes calculated in 5 patients by SPECT (threshold level 20%) using 99m Tc-macroaggregated albumin (MAA), related very closely to the actually measured lung volumes. This results prompted us to calculate the total lung volume and the volume of the lobe to be resected in 18 patients with lung cancer by SPECT. Based on the data obtained, postoperative respiratory function was predicted. The predicted values of forced vital capacity (FVC), forced expiratory volume (FEV 1.0 ), and maximum vital volume (MVV) showed closer correlations with the actually measured postoperative values (FVC, FEV 1.0 , MVV : r=0.944, r=0.917, r=0.795 respectively), than the values predicted by the ordinary lung perfusion scanning. This method facilitates more detailed evaluation of local lung function on a lobe-by-lobe basis, and can be applied clinically to predict postoperative respiratory function. (author)

  9. The effect of laser power, blood perfusion, thermal and optical properties of human liver tissue on thermal damage in LITT.

    Science.gov (United States)

    Shibib, Khalid Salem; Munshid, Mohammed A; Lateef, Hind Ali

    2017-12-01

    In this work, the finite-element method (FEM) was used to predict the temperature distribution, and the thermal damage volume in human liver tissue subjected to laser in laser-induced interstitial thermotherapy (LITT). The effect of laser power, blood perfusion, and thermal and optical properties on maximum temperature and thermal damage volume were predicted using the finite-element method. A computer program was written in visual basic language, which was verified by comparing its result with data published elsewhere. The bio-heat equation together with the effect of linear laser source were used to simulate heat transfer through tissue from which the temperature distributions, and the subsequent thermal damage, were obtained based on Arrhenius equation. In this mathematical model for LITT, it was found that increasing laser power, absorption, and scattering coefficient increased the damage zone while increasing tissue water content, perfusion rate, and tissue anisotropy factor decreased the damage zone. These findings are important aspects for doctors in the pre-estimation of the damage zone before starting the therapy so as to kill only the desired zone.

  10. Perfusion measurements of the brain: using dynamic CT for the quantitative assessment of cerebral ischemia in acute stroke

    International Nuclear Information System (INIS)

    Klotz, Ernst; Koenig, Matthias

    1999-01-01

    Objective: Perfusion CT has been successfully used as a functional imaging technique for the differential diagnosis of patients with hyperacute stroke. We investigated to what extent this technique can also be used for the quantitative assessment of cerebral ischemia. Methods and material: We studied linearity, spatial resolution and noise behaviour of cerebral blood flow (CBF) determination with computer simulations and phantom measurements. Statistical ROI based analysis of CBF images of a subset of 38 patients from a controlled clinical stroke study with currently more than 75 patients was done to check the power of relative cerebral blood flow (rCBF) values to predict definite infarction and ischemic penumbra. Classification was performed using follow-up CT and MR data. Results: Absolute CBF values were systematically underestimated, the degree depended on the cardiac output of the patients. Phantom measurements and simulations indicated very good linearity allowing reliable calculation of rCBF values. Infarct and penumbra areas in 19 patients receiving standard heparin therapy had mean rCBF values of 0.19 and 0.62, respectively. The corresponding values for 19 patients receiving local intraarterial fibrinolysis were 0.18 and 0.57. The difference between infarct and penumbra values was highly significant (P<0.0001) in both groups. No penumbra area was found with an rCBF value of less than 0.20. While in the heparin group only 25% of all areas with an rCBF between 0.20 and 0.35 survived, in the fibrinolytic group 61% of these areas could be saved (P<0.05). Conclusion: Perfusion CT is a fast and practical technique for routine clinical application. It provides substantial and important additional information for the selection of the optimal treatment strategy for patients with hyperacute stroke. Relative values of cerebral blood flow discriminate very well between areas of reversible and irreversible ischemia; an rCBF value of 0.20 appears to be a definite lower

  11. Evaluation of blood perfusion in liver cirrhosis by dynamic contrast enhanced computed tomography

    DEFF Research Database (Denmark)

    Andersen, Mette L.; Fallentin, Eva; Lauridsen, Carsten Ammitzbøl

    2017-01-01

    -CT), in patients with varying degrees of cirrhosis categorised by Child Pugh score (CP). We compared the perfusion values and the hepatic perfusion index (HPI) ((AP/AP+PP) x 100) in between the three respective CP groups, to evaluate if AP, PP and HPI correlated with the CP level and hepatic venous pressure...... patients, and C in six patients. The mean values of AP were significantly increased in patients with CP C vs. A+B, (70,4 ml/ vs. 43.1) ml/min/100ml tissue (p=0.0003). Patients with Child Pugh A tended to have higher PP values, 117,7 and Child B+C 105.3 ml/min/100ml tissue, respectively (p=0,44). The HPI...... increased significant with the degree of cirrhosis (mean A 29.6/B 30,96/C 44.9 ml/min/100ml tissue ANOVA p=0,046). Testing for linear regression with PP and HVPG values, the r-values raised with CP score (CP A r=0,137 p=0,049, CP B r=0,314 p=0,215 and CP C r=0,427 p=0,12). We found no correlation between...

  12. Noninvasive measurements of regional cerebral perfusion in preterm and term neonates by magnetic resonance arterial spin labeling

    DEFF Research Database (Denmark)

    Miranda Gimenez-Ricco, Maria Jo; Olofsson, K; Sidaros, Karam

    2006-01-01

    Magnetic resonance arterial spin labeling (ASL) at 3 Tesla has been investigated as a quantitative technique for measuring regional cerebral perfusion (RCP) in newborn infants. RCP values were measured in 49 healthy neonates: 32 preterm infants born before 34 wk of gestation and 17 term-born neon......Magnetic resonance arterial spin labeling (ASL) at 3 Tesla has been investigated as a quantitative technique for measuring regional cerebral perfusion (RCP) in newborn infants. RCP values were measured in 49 healthy neonates: 32 preterm infants born before 34 wk of gestation and 17 term...

  13. 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

  14. 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.

  15. Cerebral blood perfusion changes in amputees with myoelectric hands after rehabilitation: a SPECT computer-aided analysis.

    Science.gov (United States)

    Liu, Qiufang; Zheng, Xiujuan; Li, Panli; Xu, Lian; He, Longwen; Mei, Zhao; Zhu, Yinyan; Huang, Gang; Zhong, Chunlong; Song, Shaoli

    2016-08-31

    Rehabilitation, which is essential for amputees with myoelectric hands, can improve the quality of daily life by remodeling the neuron network. In our study, we aim to develop a cerebral blood perfusion (CBF) single-photon emission computed tomography computer-aided (SPECT-CA) detection scheme to automatically locate the brain's activated regions after rehabilitation. Five participants without forearms (three male, two female, mean age 51 ± 12.89 years, two missing the right side, and three missing the left side) were included in our study. In the clinical assessment, all of the participants received higher scores after training. The results of the SPM analysis indicated that CBF in the precentral gyrus, postcentral gyrus, frontal lobe, temporal lobe and cerebellum was significantly different among the five participants (P rehabilitation with high sensitivity and accuracy. This method has great potential for locating the remodeled neuron regions of amputees with myoelectric hands after rehabilitation.

  16. Effects of intracavitary blood flow and electrode-target distance on radiofrequency power required for transient conduction block in a Langendorff-perfused canine model

    NARCIS (Netherlands)

    Simmers, T. A.; de Bakker, J. M.; Coronel, R.; Wittkampf, F. H.; van Capelle, F. J.; Janse, M. J.; Hauer, R. N.

    1998-01-01

    OBJECTIVES: We sought to quantify the effects of electrode-target distance and intracavitary blood flow on radiofrequency (RF) power required to induce transient conduction block, using a Langendorff-perfused canine ablation model. BACKGROUND: Given the thermally mediated nature of RF catheter

  17. Re-thinking resuscitation: Leaving blood pressure cosmetics behind and moving forward to permissive hypotension and a tissue perfusion-based approach

    NARCIS (Netherlands)

    M.W. Dünser (Martin); E.P. Takala; A. Brunauer (Andreas); J. Bakker (Jan)

    2013-01-01

    textabstractDefinitions of shock and resuscitation endpoints traditionally focus on blood pressures and cardiac output. This carries a high risk of overemphasizing systemic hemodynamics at the cost of tissue perfusion. In line with novel shock definitions and evidence of the lack of a correlation

  18. Perfusion index as a possible predictor for postanesthetic shivering.

    Science.gov (United States)

    Kuroki, Chiharu; Godai, Kohei; Hasegawa-Moriyama, Maiko; Kuniyoshi, Tamotsu; Matsunaga, Akira; Kanmura, Yuichi; Kuwaki, Tomoyuki

    2014-02-01

    Postanesthetic shivering can be triggered by surgical stress and several aspects of anesthetic management and is frequently preceded by a decrease in peripheral blood flow due to thermoregulatory vasoconstriction. As perfusion index correlates with peripheral blood flow, we examined whether perioperative perfusion index, measured using pulse oximetry, might be correlated with postanesthetic shivering. Twenty-eight patients presenting for elective abdominal surgery were enrolled. Core (esophagus) and peripheral (finger) temperatures and perfusion index were recorded in the perioperative periods. Correlations between perfusion index and peripheral temperature and core-to-peripheral temperature gradient were then explored. Plasma levels of epinephrine and norepinephrine were also measured. The extent of shivering was graded after emergence from anesthesia. Perfusion index declined before emergence from anesthesia in patients who then developed postanesthetic shivering. This coincided with the time at which the difference between core and peripheral temperature became dissociated and peripheral temperature declined. Perioperative perfusion index was correlated with peripheral temperature and peripheral-core temperature gradient. Perfusion index at closure of the peritoneum predicted postanesthetic shivering and was significantly correlated with the extent of shivering. Plasma levels of both epinephrine and norepinephrine were significantly elevated after shivering events. Perfusion index was significantly lower in patients with postanesthetic shivering before emergence from anesthesia, indicating that measurement of perfusion index during and before the end of anesthesia might be a useful means of predicting postanesthetic shivering.

  19. Thyroxine (T4 Transfer from Blood to Cerebrospinal Fluid in Sheep Isolated Perfused Choroid Plexus: Role of Multidrug Resistance-Associated Proteins and Organic Anion Transporting Polypeptides

    Directory of Open Access Journals (Sweden)

    Kazem Zibara

    2017-05-01

    Full Text Available Thyroxine (T4 enters the brain either directly across the blood–brain barrier (BBB or indirectly via the choroid plexus (CP, which forms the blood–cerebrospinal fluid barrier (B-CSF-B. In this study, using isolated perfused CP of the sheep by single-circulation paired tracer and steady-state techniques, T4 transport mechanisms from blood into lateral ventricle CP has been characterized as the first step in the transfer across the B-CSF-B. After removal of sheep brain, the CPs were perfused with 125I-T4 and 14C-mannitol. Unlabeled T4 was applied during single tracer technique to assess the mode of maximum uptake (Umax and the net uptake (Unet on the blood side of the CP. On the other hand, in order to characterize T4 protein transporters, steady-state extraction of 125I-T4 was measured in presence of different inhibitors such as probenecid, verapamil, BCH, or indomethacin. Increasing the concentration of unlabeled-T4 resulted in a significant reduction in Umax%, which was reflected by a complete inhibition of T4 uptake into CP. In fact, the obtained Unet% decreased as the concentration of unlabeled-T4 increased. The addition of probenecid caused a significant inhibition of T4 transport, in comparison to control, reflecting the presence of a carrier mediated process at the basolateral side of the CP and the involvement of multidrug resistance-associated proteins (MRPs: MRP1 and MRP4 and organic anion transporting polypeptides (Oatp1, Oatp2, and Oatp14. Moreover, verapamil, the P-glycoprotein (P-gp substrate, resulted in ~34% decrease in the net extraction of T4, indicating that MDR1 contributes to T4 entry into CSF. Finally, inhibition in the net extraction of T4 caused by BCH or indomethacin suggests, respectively, a role for amino acid “L” system and MRP1/Oatp1 in mediating T4 transfer. The presence of a carrier-mediated transport mechanism for cellular uptake on the basolateral membrane of the CP, mainly P-gp and Oatp2, would account

  20. A compact instrument to measure perfusion of vasculature in transplanted maxillofacial free flaps

    Science.gov (United States)

    Kolodziejski, Noah J.; Stapels, Christopher J.; McAdams, Daniel R.; Fernandez, Daniel E.; Podolsky, Matthew J.; Farkas, Dana; Ward, Brent B.; Vartarian, Mark; Feinberg, Stephen E.; Lee, Seung Yup; Parikh, Urmi; Mycek, Mary-Ann; Christian, James F.

    2016-03-01

    The vascularization and resulting perfusion of transferred tissues are critical to the success of grafts in buried free flap transplantations. To enable long-term clinical monitoring of grafted tissue perfusion during neovascularization and endothelialization, we are developing an implantable instrument for the continuous monitoring of perfusion using diffuse correlation spectroscopy (DCS), and augmented with diffuse reflectance spectroscopy (DRS). This work discusses instrument construction, integration, and preliminary results using a porcine graft model.

  1. Dynamic contrast-enhanced quantitative perfusion measurement of the brain using T-1-weighted MRI at 3T

    DEFF Research Database (Denmark)

    Larsson, H.B.W.; Hansen, A.E.; Berg, H.K.

    2008-01-01

    Purpose: To develop a method for the measurement of brain perfusion based on dynamic contrast-enhanced T-1-weighted MR imaging. Materials and Methods: Dynamic imaging of the first pass of a bolus of a paramagnetic contrast agent was performed using a 3T whole-body magnet and a T-1-weighted fast...... field echo sequence. The input function was obtained from the internal carotid artery. An initial T-1 measurement was performed in order to convert the MR signal to concentration of the contrast agent. Pixelwise and region of interest (ROI)based calculation of cerebral perfusion (CBF) was performed...... inside the infarct core was, 9 mL/100g/min in one of the stroke patients. The other stroke patient had postischemic hyperperfusion and CBF was 140 mL/100g/min. Conclusion: Absolute values of brain perfusion can be obtained using dynamic contrast-enhanced MRI. These values correspond,to expected values...

  2. 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....

  3. 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.

  4. Measurement of ventilation- and perfusion-mediated cooling during laser ablation in ex vivo human lung tumors.

    Science.gov (United States)

    Vietze, Andrea; Koch, Franziska; Laskowski, Ulrich; Linder, Albert; Hosten, Norbert

    2011-11-01

    Perfusion-mediated tissue cooling has often been described in the literature for thermal ablation therapies of liver tumors. The objective of this study was to investigate the cooling effects of both perfusion and ventilation during laser ablation of lung malignancies. An ex vivo lung model was used to maintain near physiological conditions for the specimens. Fourteen human lung lobes containing only primary lung tumors (non-small cell lung cancer) were used. Laser ablation was carried out using a Nd:YAG laser with a wavelength of 1064 nm and laser fibers with 30 mm diffusing tips. Continuous invasive temperature measurement in 10 mm distance from the laser fiber was performed. Laser power was increased at 2 W increments starting at 10 W up to a maximum power of 12-20 W until a temperature plateau around 60 °C was reached at one sensor. Ventilation and perfusion were discontinued for 6 min each to assess their effects on temperature development. The experiments lead to 25 usable temperature profiles. A significant temperature increase was observed for both discontinued ventilation and perfusion. In 6 min without perfusion, the temperature rose about 5.5 °C (mean value, Pcooling are significant influencing factors on temperature development during thermal ablation. They should be taken into account during the planning and preparation of minimally invasive lung tumor treatment in order to achieve complete ablation. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  5. Increasing heel skin perfusion by elevation.

    Science.gov (United States)

    Huber, Jacqueline; Reddy, Raj; Pitham, Tom; Huber, David

    2008-01-01

    To determine the efficacy of elevation in the primary prevention and treatment of pressure ulcers by studying the blood flow in tissue at risk of ulceration. A prospective study was used to compare different preventative devices with an elevating prosthesis. : Wollongong Hospital Wollongong, New South Wales, Australia. Normal subjects and subjects with vasculopathy were tested with their heel resting on a hospital bed, medical-grade lamb's wool, or a viscoelastic gel overlay, with or without the test prosthesis. Skin perfusion was measured throughout using a laser Doppler monitor. A device designed to elevate the heel off the bed and distribute the weight of the leg and foot on the calf. Heel capillary blood perfusion. Perfusion in the heel was significantly greater when elevated than when using the other devices tested. The differences in mean red blood cell flux were significant, with P pressure ulcer prevention and treatment and should be incorporated into health care practice.

  6. Fluorescence measurement of calcium transients in perfused rabbit heart using rhod 2.

    Science.gov (United States)

    Del Nido, P J; Glynn, P; Buenaventura, P; Salama, G; Koretsky, A P

    1998-02-01

    Surface fluorescence spectroscopy of the beating heart to measure cytosolic calcium has been limited by the need to use ultraviolet excitation light for many of the commonly used calcium indicators. Ultraviolet light in the heart produces a high level of background fluorescence and is highly absorbed, limiting tissue penetration. Visible wave-length fluorescence dyes such as rhod 2 are available; however, the lack of spectral shift with calcium binding precludes the use of ratio techniques to account for changes in cytosolic dye concentration. We have developed a method for in vivo quantitation of cytosolic rhod 2 concentration that in conjunction with calcium-dependent fluorescence measurements permits estimation of cytosolic calcium levels in perfused rabbit hearts. Reflective absorbance of excitation light by rhod 2 loaded into myocardium was used as an index of dye concentration and the ratio of fluorescence intensity to absorbance as a measure of cytosolic calcium concentration. Endothelial cell loading of rhod 2 was found to be minimal (calcium was measured in vitro to be 500 nM, and this value increased to 710 nM in the presence of 0.5 mM myoglobin. On the basis of this value and in vivo fluorescence measurements, cytosolic calcium concentration in the rabbit heart was found to be 229 +/- 90 nM at end diastole and 930 +/- 130 nM at peak systole, with peak fluorescence preceding peak ventricular pressure by approximately 40 ms. This technique should facilitate detailed analysis of calcium transients from the whole heart.

  7. Caffeine intake inverts the effect of adenosine on myocardial perfusion during stress as measured by T1 mapping

    NARCIS (Netherlands)

    Kuijpers, Dirkjan; Prakken, Niek H.; Vliegenthart, Rozemarijn; van Dijkman, Paul R. M.; van der Harst, Pim; Oudkerk, Matthijs

    2016-01-01

    Caffeine intake before adenosine stress myocardial perfusion imaging may cause false negative findings. We hypothesized that the antagonistic effect of caffeine can be measured by T1 relaxation times in rest and adenosine stress cardiac magnetic resonance imaging (CMR), as T1 mapping techniques are

  8. Post traumatic brain perfusion SPECT analysis using reconstructed ROI maps of radioactive microsphere derived cerebral blood flow and statistical parametric mapping

    International Nuclear Information System (INIS)

    McGoron, Anthony J; Capille, Michael; Georgiou, Michael F; Sanchez, Pablo; Solano, Juan; Gonzalez-Brito, Manuel; Kuluz, John W

    2008-01-01

    Assessment of cerebral blood flow (CBF) by SPECT could be important in the management of patients with severe traumatic brain injury (TBI) because changes in regional CBF can affect outcome by promoting edema formation and intracranial pressure elevation (with cerebral hyperemia), or by causing secondary ischemic injury including post-traumatic stroke. The purpose of this study was to establish an improved method for evaluating regional CBF changes after TBI in piglets. The focal effects of moderate traumatic brain injury (TBI) on cerebral blood flow (CBF) by SPECT cerebral blood perfusion (CBP) imaging in an animal model were investigated by parallelized statistical techniques. Regional CBF was measured by radioactive microspheres and by SPECT 2 hours after injury in sham-operated piglets versus those receiving severe TBI by fluid-percussion injury to the left parietal lobe. Qualitative SPECT CBP accuracy was assessed against reference radioactive microsphere regional CBF measurements by map reconstruction, registration and smoothing. Cerebral hypoperfusion in the test group was identified at the voxel level using statistical parametric mapping (SPM). A significant area of hypoperfusion (P < 0.01) was found as a response to the TBI. Statistical mapping of the reference microsphere CBF data confirms a focal decrease found with SPECT and SPM. The suitability of SPM for application to the experimental model and ability to provide insight into CBF changes in response to traumatic injury was validated by the SPECT SPM result of a decrease in CBP at the left parietal region injury area of the test group. Further study and correlation of this characteristic lesion with long-term outcomes and auxiliary diagnostic modalities is critical to developing more effective critical care treatment guidelines and automated medical imaging processing techniques

  9. 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

  10. Healing of ulcers on the feet correlated with distal blood pressure measurements in occlusive arterial disease

    DEFF Research Database (Denmark)

    Holstein, P; Lassen, N A

    1980-01-01

    The frequency of healing in subchronic ulcers in 66 feet in 62 patients with arterial occlusive disease was correlated with the systolic digital blood pressure (SDBP) and the systolic ankle blood pressure (SABP), both measured with a strain gauge, and with the skin perfusion pressure on the heel...... of healing correlated significantly with the three distal blood pressure parameters investigated, the closest correlation being with the SDBP measured at the final examination, i.e. just after healing of the ulcer or just before an inevitable major amputation. Of the 22 cases with SDBP below 20 mmHg only two...... and peripheral neuropathy were frequent in the diabetic group. The data show that the systolic digital blood pressure is a particularly valuable prognostic parameter....

  11. Blood lipid levels and SPECT of myocardium perfusion to type 2 asymptomatic diabetic patients

    International Nuclear Information System (INIS)

    Pena Quian, Yamile; Fernandez-Britto Rodriguez, Jose; Coca Perez, Marco A; Batista Cuellar, Juan F; Rochela Vazquez, Luis Manuel

    2006-01-01

    SPECT, coronary angiography and laboratories test were performed on 31 asymptomatic type 2 diabetes patients, in order to determine the relationship among the lipid levels in blood and the results of the SPECT. Patients were classified in two groups (positive SPECT or negative SPECT). Simple descriptive statistics were calculated for all variables in both groups. Positive SPECT was detected in 35,5% of the patients and negative SPECT in 64,5%.The coronary angiography and SPECT showed good correlation. Low values of HDLc showed significant association with the positive results of the SPECT. The logistical regression showed an increment of the capacity to predict a positive SPECT if the values of HDLc are used. Conclusion: The present investigation demonstrated a significant association among the low levels of HDLc in blood and the positive results of the SPECT. The low values of HDLc could predict the possibility of a positive SPECT in asymptomatic diabetic type 2 patients (au)

  12. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    NARCIS (Netherlands)

    A. Mendrik (Adrienne); E.J.P.A. Vonken; B.T.J. van Ginneken (Berbke); J.R. Riordan (John ); H.W.A.M. de Jong (Hugo); T. van Seeters (Tom); E.J. Smit (Ewoud); M.A. Viergever (Max); M. Prokop (Mathias)

    2011-01-01

    textabstractCerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of

  13. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    NARCIS (Netherlands)

    Mendrik, A.M.; Vonken, E.J.; Ginneken, B. van; Jong, H.W. de; Riordan, A.; Seeters, T. van; Smit, E.J.; Viergever, M.A.; Prokop, M.

    2011-01-01

    Cerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of x-ray

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-15

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

  15. Effects of aerobic exercise and medical nutrition intervention on endothelial injury and placental blood perfusion in patients with preeclampsia

    Directory of Open Access Journals (Sweden)

    Zhen-Ju Zhang1

    2017-06-01

    Full Text Available Objective: To study the effects of aerobic exercise and medical nutrition intervention on endothelial injury and placental blood perfusion in patients with preeclampsia. Methods: 72 cases of patients diagnosed with preeclampsia in Department of Obstetrics and Gynecology of Zigong Third People’s Hospital between January 2013 and August 2016 were selected randomly divided into two groups, the observation group received aerobic exercise, medical nutrition combined with routine intervention, and the control group received routine intervention. Before and after intervention, serum endothelial injury markers were detected. After delivery, the expression of apoptosis molecules and the contents of stress molecules caused by hypoxia in placenta were detected. Results: After intervention, serum AnnexinV, vWF, ET-1 and oxLDL contents of both groups were lower than those before intervention while NO, PLGF and ABCA1 contents were higher than those before intervention and serum AnnexinV, vWF, ET-1 and oxLDL contents of observation group were lower than those of control group while NO, PLGF and ABCA1 contents were higher than those of control group; after delivery, Bax, Fas, FasL and Caspase-3 mRNA expression as well as MDA, AOPP, CHOP and GRP78 protein contents in placenta of observation group were lower than those of control group. Conclusion: Aerobic exercise and medical nutrition intervention can reduce the endothelial injury and improve the placental hypoxia of preeclampsia.

  16. 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.

  17. TU-G-204-01: BEST IN PHYSICS (IMAGING): Dynamic CT Myocardial Perfusion Measurement and Its Comparison to Fractional Flow Reserve

    Energy Technology Data Exchange (ETDEWEB)

    Ziemer, B; Hubbard, L; Groves, E; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S [University of California, Irvine, CA (United States)

    2015-06-15

    Purpose: To evaluate a first pass analysis (FPA) technique for CT perfusion measurement in a swine animal and its validation using fractional flow reserve (FFR) as a reference standard. Methods: Swine were placed under anesthesia and relevant physiologic parameters were continuously recorded. Intra-coronary adenosine was administered to induce maximum hyperemia. A pressure wire was advanced distal to the first diagonal branch of the left anterior descending (LAD) artery for FFR measurements and a balloon dilation catheter was inserted over the pressure wire into the proximal LAD to create varying levels of stenosis. Images were acquired with a 320-row wide volume CT scanner. Three main coronary perfusion beds were delineated in the myocardium using arteries extracted from CT angiography images using a minimum energy hypothesis. The integrated density in the perfusion bed was used to calculate perfusion using the FPA technique. The perfusion in the LAD bed over a range of stenosis severity was measured. The measured fractional perfusion was compared to FFR and linear regression was performed. Results: The measured fractional perfusion using the FPA technique (P-FPA) and FFR were related as P-FPA = 1.06FFR – 0.06 (r{sup 2} = 0.86). The perfusion measurements were calculated with only three to five total CT volume scans, which drastically reduces the radiation dose as compared with the existing techniques requiring 15–20 volume scans. Conclusion: The measured perfusion using the first pass analysis technique showed good correlation with FFR measurements as a reference standard. The technique for perfusion measurement can potentially make a substantial reduction in radiation dose as compared with the existing techniques.

  18. TU-G-204-01: BEST IN PHYSICS (IMAGING): Dynamic CT Myocardial Perfusion Measurement and Its Comparison to Fractional Flow Reserve

    International Nuclear Information System (INIS)

    Ziemer, B; Hubbard, L; Groves, E; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S

    2015-01-01

    Purpose: To evaluate a first pass analysis (FPA) technique for CT perfusion measurement in a swine animal and its validation using fractional flow reserve (FFR) as a reference standard. Methods: Swine were placed under anesthesia and relevant physiologic parameters were continuously recorded. Intra-coronary adenosine was administered to induce maximum hyperemia. A pressure wire was advanced distal to the first diagonal branch of the left anterior descending (LAD) artery for FFR measurements and a balloon dilation catheter was inserted over the pressure wire into the proximal LAD to create varying levels of stenosis. Images were acquired with a 320-row wide volume CT scanner. Three main coronary perfusion beds were delineated in the myocardium using arteries extracted from CT angiography images using a minimum energy hypothesis. The integrated density in the perfusion bed was used to calculate perfusion using the FPA technique. The perfusion in the LAD bed over a range of stenosis severity was measured. The measured fractional perfusion was compared to FFR and linear regression was performed. Results: The measured fractional perfusion using the FPA technique (P-FPA) and FFR were related as P-FPA = 1.06FFR – 0.06 (r 2 = 0.86). The perfusion measurements were calculated with only three to five total CT volume scans, which drastically reduces the radiation dose as compared with the existing techniques requiring 15–20 volume scans. Conclusion: The measured perfusion using the first pass analysis technique showed good correlation with FFR measurements as a reference standard. The technique for perfusion measurement can potentially make a substantial reduction in radiation dose as compared with the existing techniques

  19. 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

  20. Identification of hemodynamically compromised regions by means of cerebral blood volume mapping utilizing computed tomography perfusion imaging.

    Science.gov (United States)

    Takahashi, Satoshi; Tanizaki, Yoshio; Akaji, Kazunori; Kimura, Hiroaki; Katano, Takehiro; Suzuki, Kentaro; Mochizuki, Yoichi; Shidoh, Satoka; Nakazawa, Masaki; Yoshida, Kazunari; Mihara, Ban

    2017-04-01

    The aim of the study was to evaluate the potential role of computed tomography perfusion (CTP) imaging in identifying hemodynamically compromised regions in patients with occlusive cerebrovascular disease. Twelve patients diagnosed with either occlusion or severe stenosis of the internal carotid artery or the M1 portion of the middle cerebral artery underwent CTP imaging. The data was analyzed by an automated ROI-determining software. Patients were classified into two subgroups: an asymptomatic group consisting of three patients in whom perfusion pressure distal to the site of occlusion/stenosis (PP dis ) could be maintained in spite of the arterial occlusion/stenosis, and a symptomatic group consisting of nine patients in whom PP dis could not be maintained enough to avoid watershed infarction. Four CTP-related parameters were independently compared between the two groups. Significant differences were determined using a two-sample t-test. When statistically significant differences were identified, cut-off points were calculated using ROC curves. Analysis revealed statistically significant differences between the asymptomatic and symptomatic subgroups only in the measure of relCBV (p=0.028). Higher relCBV values were observed in the symptomatic subgroup. ROC curve analysis revealed 1.059 to be the optimal relCBV cut-off value for distinguishing between the asymptomatic and symptomatic subgroups. The data revealed that, in patients whose PP dis is maintained, relCBV remains around 1.00. Conversely, in patients whose PP dis decreased, relCBV increased. From these findings, we conclude that elevation of relCBV as observed using CTP imaging accurately reflects the extent of compensatory vasodilatation involvement and can identify hemodynamically compromised regions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Healing of ulcers on the feet correlated with distal blood pressure measurements in occlusive arterial disease

    DEFF Research Database (Denmark)

    Holstein, P; Lassen, N A

    1980-01-01

    The frequency of healing in subchronic ulcers in 66 feet in 62 patients with arterial occlusive disease was correlated with the systolic digital blood pressure (SDBP) and the systolic ankle blood pressure (SABP), both measured with a strain gauge, and with the skin perfusion pressure on the heel...... (SPPH) as measured with a photocell. Thirty-two patients (35 feet with ulcerations) had diabetes mellitus. The treatment was conservative. In 42 feet the ulcers healed after an average period of 5.8 months; in 24 feet major amputation became necessary after an average of 4.3 months. The frequency...... of healing correlated significantly with the three distal blood pressure parameters investigated, the closest correlation being with the SDBP measured at the final examination, i.e. just after healing of the ulcer or just before an inevitable major amputation. Of the 22 cases with SDBP below 20 mmHg only two...

  2. Cerebral blood volume calculated by dynamic susceptibility contrast-enhanced perfusion MR imaging: preliminary correlation study with glioblastoma genetic profiles.

    Directory of Open Access Journals (Sweden)

    Inseon Ryoo

    Full Text Available To evaluate the usefulness of dynamic susceptibility contrast (DSC enhanced perfusion MR imaging in predicting major genetic alterations in glioblastomas.Twenty-five patients (M:F = 13∶12, mean age: 52.1±15.2 years with pathologically proven glioblastoma who underwent DSC MR imaging before surgery were included. On DSC MR imaging, the normalized relative tumor blood volume (nTBV of the enhancing solid portion of each tumor was calculated by using dedicated software (Nordic TumorEX, NordicNeuroLab, Bergen, Norway that enabled semi-automatic segmentation for each tumor. Five major glioblastoma genetic alterations (epidermal growth factor receptor (EGFR, phosphatase and tensin homologue (PTEN, Ki-67, O6-methylguanine-DNA methyltransferase (MGMT and p53 were confirmed by immunohistochemistry and analyzed for correlation with the nTBV of each tumor. Statistical analysis was performed using the unpaired Student t test, ROC (receiver operating characteristic curve analysis and Pearson correlation analysis.The nTBVs of the MGMT methylation-negative group (mean 9.5±7.5 were significantly higher than those of the MGMT methylation-positive group (mean 5.4±1.8 (p = .046. In the analysis of EGFR expression-positive group, the nTBVs of the subgroup with loss of PTEN gene expression (mean: 10.3±8.1 were also significantly higher than those of the subgroup without loss of PTEN gene expression (mean: 5.6±2.3 (p = .046. Ki-67 labeling index indicated significant positive correlation with the nTBV of the tumor (p = .01.We found that glioblastomas with aggressive genetic alterations tended to have a high nTBV in the present study. Thus, we believe that DSC-enhanced perfusion MR imaging could be helpful in predicting genetic alterations that are crucial in predicting the prognosis of and selecting tailored treatment for glioblastoma patients.

  3. The value of the renal resistive index in the measurement of renal perfusion before and after extracorporal shock wave lithotripsy in correlation to the scintigraphy, to the magnetic resonance perfusion imaging and to big-endothelin values

    International Nuclear Information System (INIS)

    Palwein-Prettner, L.

    1999-07-01

    Purpose: the goal of this study was to evaluate effects of extracorporeal shock wave lithotripsy (ESWL) on the renal perfusion using the resistive index (RI), perfusion scintigraphy, magnetic resonance (MR) perfusion imaging and plasma big-endothelin (big-ET-1) values. Method/materials: In 21 patients divided in 3 age-groups the RI was measured before and 1,3,6 and 24 hours after ESWL. Big-ET-1, a potent vasoconstrictor peptid was correlated with the RI values. The RI and Big-ET-1 results was compared to the results of the MR perfusion imaging and the scintigraphy, the gold-standard method. Results: The RI of the treated kidneys increased significantly from 0,64±0,05 to 0,72±0,08 after the ESWL (p<0,001) and in the untreated kidneys from 0,63±0,05 to 0,68±0,09 (p=0,003). The hightest age group shows the most significant increase. The Big-ET-values also increased only in this age group significantly from 0,78±0,24 fmol/l to 1,58±0,52 fmol/l. In the scintigraphy the decrease of the renal plasma flow (RPF) in this age group was most significant. The MR perfusion Imaging shows in all age groups significant decrease (p<0,001). Conclusion: we conclude that the ESWL causes considerable renal parenchymal damage only in the elderly patients. The following changes in renal perfusion were measured very sensitively with the RI which had a good correlation to the results of the perfusion scintigraphy and the MR perfusion imaging. Further studies with larger series have to evaluate these results. (author)

  4. In vivo Gd-DTPA concentration for MR lung perfusion measurements: Assessment with computed tomography in a porcine model

    Energy Technology Data Exchange (ETDEWEB)

    Puderbach, Michael [German Cancer Research Center, Department of Radiology, Heidelberg (Germany); Deutsches Krebsforschungszentrum, Department of Radiology (E010), Heidelberg (Germany); Risse, Frank; Semmler, Wolfhard [German Cancer Research Center, Department of Medical Physics in Radiology, Heidelberg (Germany); Biederer, Juergen [University Hospital Schleswig-Holstein, Department of Diagnostic Radiology, Campus Kiel (Germany); Ley-Zaporozhan, Julia; Ley, Sebastian [German Cancer Research Center, Department of Radiology, Heidelberg (Germany); University Heidelberg, Department of Pediatric Radiology, Heidelberg (Germany); Szabo, Gabor [University Heidelberg, Department of Cardiac Surgery, Heidelberg (Germany); Kauczor, Hans-Ulrich [University of Heidelberg, Department of Radiology, Heidelberg (Germany)

    2008-10-15

    A linear relationship between MR signal and contrast-agent concentration (CAC) of the arterial-input function (AIF) is crucial for MR lung-perfusion quantification. The aim was to determine the in-vivo real maximum CAC of the AIF, using cine CT measurements in a porcine model. A dilution series (Gd-DTPA, 0-20 mM) was examined by clinical time-resolved 3D-GRE MRI and by MDCT in cine CT mode. Using the CT setup, data were acquired in five pigs immediately after the injection of 0.05 mmol and 0.07 mmol/kg BW Gd-DTPA. For phantom measurements, mean signal values were determined using a region-of-interest (ROI) analysis and for animal measurements, a ROI was placed in the pulmonary trunk of the cine CT perfusion data sets. The CT phantom measurements were used to calculate the in-vivo maximum CAC corresponding to the HU values obtained in the pulmonary trunk by the cine CT study. Linearity of the AIF of the CT perfusion measurements was verified using the MR phantom measurement results. MR phantom measurements demonstrated linearity for concentrations of 0-4 mM. CT phantom measurements showed linear relation for the entire CAC range. Comparing in-vivo and in-vitro measurements, three of five CA injections at 0.05 mmol/kg and all 0.07 mmol/kg injections exceeded the range of linearity in MRI. The CA dose for quantification of lung perfusion with time-resolved MR studies must be chosen carefully since even with low doses (0.05 mmol/kg) the CAC may exceed the range of linearity in the AIF. (orig.)

  5. 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)

  6. [Invasive blood pressure measurements. Factual safety].

    Science.gov (United States)

    Nielsen, L H

    1994-08-01

    Intra-arterial blood pressure measurement is often used in patients with unstable haemodynamics. The demand for accuracy in such measurements is high. Usually these demands are fulfilled, but situations can occur where the dynamic characteristics of the system are exceeded. In order to acknowledge this situation, one must be aware of these dynamic characteristics. The significance of the system's resonance frequency and damping is described. A method to control the usability of the system is described.

  7. Estimation of rat muscle blood flow by microdialysis probes perfused with ethanol, [14C]ethanol, and 3H2O

    DEFF Research Database (Denmark)

    Stallknecht, B; Donsmark, M; Enevoldsen, L H

    1999-01-01

    rates ranging from 0 to 21 ml. 100 g-1. min-1. The microdialysis probes were perfused at 2 microliter/min with perfusate containing ethanol, [14C]ethanol, and 3H2O. Within and between experiments outflow-to-inflow ratios (o/i) generally varied inversely with blood flow. When a low flow or no flow...... was maintained in hindquarters, o/i ratios first increased with time (for at least 60 min) and then leveled off. The long time constant impaired detection of rapid oscillations in blood flow, especially at low blood flow rates. Contractions per se apparently decreased o/i ratios independent of blood flow....... Ethanol and [14C]ethanol o/i ratios did not differ. 3H2O o/i paralleled ethanol and [14C]ethanol o/i ratios but it was significantly lower. In conclusion, differences in skeletal muscle blood flow can be detected by the microdialysis technique. However, the slow changes in o/i, in particular at low blood...

  8. Radionuclide ventilation-perfusion studies in pediatric respiratory diseases: 157 measurements of the distribution of ventilation and perfusion in 130 children

    International Nuclear Information System (INIS)

    Guillet, J.; Basse-Cathalinat, B.; Christophe, E.; Saudubray, F.

    1983-01-01

    Radionuclide investigations provide regional quantitative and kinetic data with a very low exposure. Results are dissonant with roentgenographic findings in 52% of cases and enhance diagnostic and prognostic accuracy. Although it provides poor quality images. The use of 133 Xe is preferable for ventilation studies to ensure correct evaluation of washout and trapping. According to the patient's age and position, 50% washout times vary from 5.6 to 8.7 seconds in the upper segments and from 5.6 to 8.5 seconds in the lower segments. Distribution of blood flow can be studied after intravenous injection of either sup(99m)Tc labelled microspheres of human albumin or 133 Xe saline solution. The former provides better quality images with studies of all incidences but may be contraindicated in cases of severe pulmonary hypertension or major right-to-left shunts. The latter allows a better sequential study. Radionuclide ventilation-perfusion studies are one of the major advances in pediatric pneumology in recent years [fr

  9. Childhood Cerebral Adrenoleukodystrophy: MR Perfusion Measurements and Their Use in Predicting Clinical Outcome after Hematopoietic Stem Cell Transplantation.

    Science.gov (United States)

    McKinney, A M; Benson, J; Nascene, D R; Eisengart, J; Salmela, M B; Loes, D J; Zhang, L; Patel, K; Raymond, G V; Miller, W P

    2016-09-01

    MR perfusion has shown abnormalities of affected WM in cerebral X-linked adrenoleukodystrophy, but serial data is needed to explore the import of such findings after hematopoietic stem cell transplantation. Our aim was to prospectively measure MR perfusion parameters in patients with cerebral adrenoleukodystrophy pre- and post-hematopoietic stem cell transplantation, and to correlate those measurements with clinical outcome. Ten patients with cerebral adrenoleukodystrophy prospectively underwent DSC-MR perfusion imaging at adrenoleukodystrophy at each time point and compared with those in controls. Correlations were calculated between the pre-hematopoietic stem cell transplantation MR perfusion values and 1-year clinical scores, with P value adjustment for multiple comparisons. At baseline in patients with cerebral adrenoleukodystrophy, both relative CBV and relative CBF within the splenium of the corpus callosum and parieto-occipital WM significantly differed from those in controls (P = .005-.031) and remained so 1 year post-hematopoietic stem cell transplantation (P = .003-.005). Meanwhile, no MR perfusion parameter within the leading enhancing edge differed significantly from that in controls at baseline or at 1 year (P = .074-.999) or significantly changed by 1 year post-hematopoietic stem cell transplantation (P = .142-.887). Baseline Loes scores correlated with 1-year clinical neurologic function (r = 0.813, P adrenoleukodystrophy, suggesting local disease stabilization. Meanwhile, parieto-occipital WM and splenium of the corpus callosum relative CBV and relative CBF values worsened; this change signified irreversible injury. Baseline splenium of the corpus callosum relative CBV may predict clinical outcomes following hematopoietic stem cell transplantation. © 2016 by American Journal of Neuroradiology.

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

    NARCIS (Netherlands)

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

    2016-01-01

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

  11. 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.

  12. Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications

    International Nuclear Information System (INIS)

    Peladeau-Pigeon, M; Coolens, C

    2013-01-01

    Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters remains an outstanding problem to address prior to perfusion imaging becoming a widespread standard as a non-invasive quantitative measurement tool. One approach to this validation process has been the development of quality assurance phantoms in order to facilitate controlled perfusion ex vivo. However, most of these systems fail to establish and accurately replicate physiologically relevant capillary permeability and exchange performance. The current work presents the first step in the development of a prospective suite of physics-based perfusion simulations based on coupled fluid flow and particle transport phenomena with the goal of enhancing the understanding of clinical contrast agent kinetics. Existing knowledge about a controllable, two-compartmental fluid exchange phantom was used to validate the computational fluid dynamics (CFD) simulation model presented herein. The sensitivity of CFD-derived contrast uptake curves to contrast injection parameters, including injection duration and flow rate, were quantified and found to be within 10% accuracy. The CFD model was employed to evaluate two commonly used clinical kinetic algorithms used to derive perfusion parameters: Fick's principle and the modified Tofts model. Neither kinetic model was able to capture the true transport phenomena it aimed to represent but if the overall contrast concentration after injection remained identical, then successive DCE-CT evaluations could be compared and could indeed reflect differences in regional tissue flow. This study sets the groundwork for future explorations in phantom development and pharmaco-kinetic modelling, as well as the development of novel contrast

  13. Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications.

    Science.gov (United States)

    Peladeau-Pigeon, M; Coolens, C

    2013-09-07

    Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters remains an outstanding problem to address prior to perfusion imaging becoming a widespread standard as a non-invasive quantitative measurement tool. One approach to this validation process has been the development of quality assurance phantoms in order to facilitate controlled perfusion ex vivo. However, most of these systems fail to establish and accurately replicate physiologically relevant capillary permeability and exchange performance. The current work presents the first step in the development of a prospective suite of physics-based perfusion simulations based on coupled fluid flow and particle transport phenomena with the goal of enhancing the understanding of clinical contrast agent kinetics. Existing knowledge about a controllable, two-compartmental fluid exchange phantom was used to validate the computational fluid dynamics (CFD) simulation model presented herein. The sensitivity of CFD-derived contrast uptake curves to contrast injection parameters, including injection duration and flow rate, were quantified and found to be within 10% accuracy. The CFD model was employed to evaluate two commonly used clinical kinetic algorithms used to derive perfusion parameters: Fick's principle and the modified Tofts model. Neither kinetic model was able to capture the true transport phenomena it aimed to represent but if the overall contrast concentration after injection remained identical, then successive DCE-CT evaluations could be compared and could indeed reflect differences in regional tissue flow. This study sets the groundwork for future explorations in phantom development and pharmaco-kinetic modelling, as well as the development of novel contrast

  14. Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications

    Science.gov (United States)

    Peladeau-Pigeon, M.; Coolens, C.

    2013-09-01

    Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters remains an outstanding problem to address prior to perfusion imaging becoming a widespread standard as a non-invasive quantitative measurement tool. One approach to this validation process has been the development of quality assurance phantoms in order to facilitate controlled perfusion ex vivo. However, most of these systems fail to establish and accurately replicate physiologically relevant capillary permeability and exchange performance. The current work presents the first step in the development of a prospective suite of physics-based perfusion simulations based on coupled fluid flow and particle transport phenomena with the goal of enhancing the understanding of clinical contrast agent kinetics. Existing knowledge about a controllable, two-compartmental fluid exchange phantom was used to validate the computational fluid dynamics (CFD) simulation model presented herein. The sensitivity of CFD-derived contrast uptake curves to contrast injection parameters, including injection duration and flow rate, were quantified and found to be within 10% accuracy. The CFD model was employed to evaluate two commonly used clinical kinetic algorithms used to derive perfusion parameters: Fick's principle and the modified Tofts model. Neither kinetic model was able to capture the true transport phenomena it aimed to represent but if the overall contrast concentration after injection remained identical, then successive DCE-CT evaluations could be compared and could indeed reflect differences in regional tissue flow. This study sets the groundwork for future explorations in phantom development and pharmaco-kinetic modelling, as well as the development of novel contrast

  15. Glucose-induced time-dependent potentiation of insulin release, but not islet blood perfusion, in anesthetized rats.

    Science.gov (United States)

    Jansson, Leif; Bodin, Birgitta; Källskog, Orjan

    2008-01-01

    Repeated administration of glucose in vivo leads to a time-dependent potentiation of insulin release. Glucose is also known to stimulate pancreatic islet blood flow, but whether this is associated with a time-dependent potentiation is unknown. We therefore repeatedly administered glucose to anesthetized rats and evaluated effects on insulin release and islet blood flow. Male Wistar-Furth rats, anesthetized with thiobutabarbital, were injected intravenously with 1 ml of saline or glucose at times 0, 30 and 60 min. The combinations used were saline + saline + saline (SSS), glucose + saline + saline (GSS), saline + saline + glucose (SSG) and glucose + glucose + glucose (GGG). Regional organ blood flow values were measured 3 min after the final injection with a microsphere technique, and at this time also serum insulin concentrations were determined with ELISA. Serum insulin concentrations as well as total pancreatic, pancreatic islet and duodenal blood flow were higher in SSG and GGG-treated rats when compared to those given SSS and GSS. However, only insulin concentrations, not blood flow values, were higher in GGG rats when compared to SSG animals. Glucose-induced time-dependent potentiation of insulin release occurs in vivo in thiobutabarbital-anesthetized rats, but is not associated with a further increase in islet blood flow.

  16. 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.

  17. Limbic system perfusion in Alzheimer's disease measured by MRI-coregistered HMPAO SPET

    Energy Technology Data Exchange (ETDEWEB)

    Callen, David J.A. [Institute of Medical Science, Research Program in Aging, Imaging, Sunnybrook and Women' s University of Toronto, ON (Canada); Black, Sandra E. [Cognitive Neurology Unit and Research Program in Aging, Sunnybrook and Women' s College Health Sciences Centre, Toronto, ON (Canada); Institute of Medical Science, Research Program in Aging, Imaging, Sunnybrook and Women' s University of Toronto, ON (Canada); Department of Medicine (Neurology), University of Toronto, ON (Canada); Caldwell, Curtis B. [Department of Medical Imaging, Sunnybrook and Women' s College Health Sciences Centre and University of Toronto, CN (Canada)

    2002-07-01

    The goal of this study was to perform a systematic, semi-quantitative analysis of limbic perfusion in patients with Alzheimer's disease (AD) using coregistered single-photon emission tomography (SPET) images aligned to magnetic resonance (MR) images. Limbic perfusion in 40 patients with mild to moderate AD was compared with that of 17 age-, sex-, and education-matched normal controls (NC). HMPAO SPET scans and 3D T1-weighted MR images were acquired for each subject. Structures of the limbic system (i.e. hippocampus, amygdala, anterior thalamus, hypothalamus, mamillary bodies, basal forebrain, septal area and cingulate, orbitofrontal and parahippocampal cortices) were traced on the MR images and transferred to the coregistered SPET scans. Perfusion ratios for all limbic regions were calculated relative to cerebellar perfusion. General linear model multivariate analysis revealed that, overall, limbic structures showed significant hypoperfusion (F=7.802, P<0.00001, {eta}{sup 2}=0.695) in AD patients compared with NC. Greatest differences (d{>=}0.8) were found in the hippocampus, as well as all areas of the cingulate cortex. Significant relative hypoperfusion was also apparent in the parahippocampal cortex, amygdala/entorhinal cortex, septal area and anterior thalamus, all of which showed medium to large effect sizes (d=0.6-0.8). No significant relative perfusion differences were detected in the basal forebrain, hypothalamus, mamillary bodies or orbitofrontal cortex. Logistic regression indicated that posterior cingulate cortex perfusion was able to discriminate AD patients from NC with 93% accuracy (95% sensitivity, 88% specificity). The current results suggest that most, but not all, limbic structures show significant relative hypoperfusion in AD. These findings validate previous post-mortem studies and could be useful in improving diagnostic accuracy, monitoring disease progression and evaluating potential treatment strategies in AD. (orig.)

  18. Ventilation-perfused studies using SPECT

    International Nuclear Information System (INIS)

    Zwijnenburg, A.

    1989-01-01

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

  19. Changes in pulse rate, respiratory rate, blood oxygenation, perfusion index, skin conductance, and their variability induced during and after grounding human subjects for 40 minutes.

    Science.gov (United States)

    Chevalier, Gaetan

    2010-01-01

    Previous studies have shown that grounding produces quantifiable physiologic changes. This study was set up to reproduce and expand earlier electrophysiologic and physiologic parameters measured immediately after grounding with improved methodology and state-of-the-art equipment. A multiparameter double-blind experiment was conducted with 14 men and 14 women (age range: 18-80) in relatively good health. Subjects were screened for health problems using a commonly used health questionnaire. They were seated in a comfortable recliner and measured during 2-hour grounding sessions, leaving time for signals to stabilize before, during, and after grounding (40 minutes for each period). Sham 2-hour grounding sessions were also recorded with the same subjects as controls. This report presents results for 5 of the 18 parameters measured. The parameters reported here are: skin conductance (SC), blood oxygenation (BO), respiratory rate (RR), pulse rate (PR), and perfusion index (PI). This study was performed in a rented facility in Encinitas, California. The facility was chosen in a quiet area for its very low electromagnetic noise. For each session, statistical analyses were performed on four 10-minute segments: before and after grounding (sham grounding for control session) and before and after ungrounding (sham ungrounding). There was an immediate decrease in SC at grounding and an immediate increase at ungrounding on all subjects. RR increased during grounding, and the effect lasted after ungrounding. RR variance increased immediately after grounding then decreased. BO variance decreased during grounding, followed by a dramatic increase after ungrounding. PR and PI variances increased toward the end of the grounding period, and this change persisted after ungrounding. These results warrant further research to determine how grounding affects the body. Grounding could become important for relaxation, health maintenance and disease prevention.

  20. Influence of antihypertensive therapy on cerebral perfusion in patients with metabolic syndrome: relationship with cognitive function and 24-h arterial blood pressure monitoring.

    Science.gov (United States)

    Efimova, Nataliya Y; Chernov, Vladimir I; Efimova, Irina Y; Lishmanov, Yuri B

    2015-08-01

    To investigate the regional cerebral blood flow, cognitive function, and parameters of 24-h arterial blood pressure monitoring in patients with metabolic syndrome before and after combination antihypertensive therapy. The study involved 54 patients with metabolic syndrome (MetS) investigated by brain single-photon emission computed tomography, 24-h blood pressure monitoring (ABPM), and comprehensive neuropsychological testing before and after 24 weeks of combination antihypertensive therapy. Patients with metabolic syndrome had significantly poorer regional cerebral blood flow compared with control group: by 7% (P = 0.003) in right anterior parietal cortex, by 6% (P = 0.028) in left anterior parietal cortex, by 8% (P = 0.007) in right superior frontal lobe, and by 10% (P = 0.00002) and 7% (P = 0.006) in right and left temporal brain regions, correspondingly. The results of neuropsychological testing showed 11% decrease in mentation (P = 0.002), and 19% (P = 0.011) and 20% (P = 0.009) decrease in immediate verbal and visual memory in patients with MetS as compared with control group. Relationships between the indices of ABPM, cerebral perfusion, and cognitive function were found. Data showed an improvement of regional cerebral blood flow, ABPM parameters, and indicators of cognitive functions after 6 months of antihypertensive therapy in patients with MetS. The study showed the presence of diffuse disturbances in cerebral perfusion is associated with cognitive disorders in patients with metabolic syndrome. Combination antihypertensive treatment exerts beneficial effects on the 24-h blood pressure profile, increases cerebral blood flow, and improves cognitive function in patients with MetS. © 2015 John Wiley & Sons Ltd.

  1. Polynomial analysis of ambulatory blood pressure measurements

    NARCIS (Netherlands)

    Zwinderman, A. H.; Cleophas, T. A.; Cleophas, T. J.; van der Wall, E. E.

    2001-01-01

    In normotensive subjects blood pressures follow a circadian rhythm. A circadian rhythm in hypertensive patients is less well established, and may be clinically important, particularly with rigorous treatments of daytime blood pressures. Polynomial analysis of ambulatory blood pressure monitoring

  2. Contribution of quantitative perfusion pulmonary scintiscanning with particles to the study of the regional pulmonary blood flow distribution

    International Nuclear Information System (INIS)

    Barreto, S.S.M.

    1988-01-01

    The quantitative perfusion pulmonary scintiscanning with macro aggregates was studied by digital images of perfusion, obtained in scintiscanning chamber coupled to the data processing system. The study was developed in four phases, in the Nuclear Medicine Service of Porto Alegre Clinical Hospital. In each phase, it was studied groups with different ages and different clinical aspects (normal and cardiopathic persons), and they were submitted to several diagnostic techniques. The macro aggregates used was the human albumin and was labelled with technetium 99. A comparative evaluation of this method with others diagnostic techniques was also presented. (C.G.C)

  3. Skin perfusion pressure measured with a photo sensor in an air-filled plastic balloon: validity and reproducibility on the lower leg in normal subjects and patients suspected of obliterative arterial disease

    International Nuclear Information System (INIS)

    Nielsen, Steen Levin; Nielsen, Anne Lerberg; Vind, Susanne Haase; Thomassen, Anders

    2011-01-01

    An inflatable small plastic bag including a photo sensor was constructed for measurement of skin perfusion pressure avoiding the rim of the photo sensor over bony and tendineous surfaces of the tibia below the knee, at the ankle, and on the dorsal forefoot. Compression was obtained using a conical blood pressure cuff with continuous decrease from suprasystolic arm pressure. The validity of skin perfusion pressure with the new device was compared to that of isotope washout below the knee in normal subjects and in patients with an ischemic forefoot with acceptable agreement. The method had a high reproducibility within and between days in normal subjects. Compared to systolic arterial pressure measured using a strain gauge with a cuff on the ankle in normal subjects and patients with intermittent claudication the new device showed blood pressure in the skin closer to the diastolic pressure. The new pressure device thus had acceptable validity and reproducibility for estimation of the skin perfusion pressure and can be used on bony and tendineous sites on the lower limb in regions where critical wound healing is frequent, e.g. ankle and forefoot

  4. Compilation of basal metabolic and blood perfusion rates in various multi-compartment, whole-body thermoregulation models

    Science.gov (United States)

    Shitzer, Avraham; Arens, Edward; Zhang, Hui

    2016-07-01

    The assignments of basal metabolic rates (BMR), basal cardiac output (BCO), and basal blood perfusion rates (BBPR) were compared in nine multi-compartment, whole-body thermoregulation models. The data are presented at three levels of detail: total body, specific body regions, and regional body tissue layers. Differences in the assignment of these quantities among the compared models increased with the level of detail, in the above order. The ranges of variability in the total body BMR was 6.5 % relative to the lowest value, with a mean of 84.3 ± 2 W, and in the BCO, it was 8 % with a mean of 4.70 ± 0.13 l/min. The least variability among the body regions is seen in the combined torso (shoulders, thorax, and abdomen: ±7.8 % BMR and ±5.9 % BBPR) and in the combined head (head, face, and neck ±9.9 % BMR and ±10.9 % BBPR), determined by the ratio of the standard deviation to the mean. Much more variability is apparent in the extremities with the most showing in the BMR of the feet (±117 %), followed by the BBPR in the arms (±61.3 %). In the tissue layers, most of the bone layers were assigned zero BMR and BBPR, except in the shoulders and in the extremities that were assigned non-zero values in a number of models. The next lowest values were assigned to the fat layers, with occasional zero values. Skin basal values were invariably non-zero but involved very low values in certain models, e.g., BBPR in the feet and the hands. Muscle layers were invariably assigned high values with the highest found in the thorax, abdomen, and legs. The brain, lung, and viscera layers were assigned the highest of all values of both basal quantities with those of the brain layers showing rather tight ranges of variability in both basal quantities. Average basal values of the "time-seasoned" models presented in this study could be useful as a first step in future modeling efforts subject to appropriate adjustment of values to conform to most recently available and reliable data.

  5. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

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

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...... of Gd-DTPA (lambda), the vascular blood volume (Vb), and the time delay through the coronary arteries (delta T). The model was evaluated by computer simulation and used on experimental results from seven healthy subjects. The results in the healthy volunteers for a region of interest placed...... in the anterior myocardial wall were (mean +/- SD) Ki = 54 +/- 10 ml/100 g/min, lambda = 30 +/- 3 ml/100 g, Vb = 9 +/- 2 ml/100 g, delta T = 3.2 +/- 1.1 s. These results are in good agreement with similar results obtained by other methods....

  6. Novel idea to monitor and measure blood hemoglobin noninvasively ...

    African Journals Online (AJOL)

    Measuring blood hematocrit noninvasively is reviewed in this paper. Although there is an inclination to measure the hematocrit by determining the bioelectrical impedance of the blood, in vitro experimental methods still remain practically inapplicable. The blood sample size is determined when blood samples are examined.

  7. Tissue perfusion rate estimation with compression-based photoacoustic-ultrasound imaging

    Science.gov (United States)

    Choi, Min; James Shapiro, A. M.; Zemp, Roger

    2018-01-01

    Tissue perfusion is essential for transporting blood oxygen and nutrients. Measurement of tissue perfusion rate would have a significant impact in clinical and preclinical arenas. However, there are few techniques to image this important parameter and they typically require contrast agents. A label-free methodology based on tissue compression and imaging with a high-frequency photoacoustic-ultrasound system is introduced for estimating and visualizing tissue perfusion rates. Experiments demonstrate statistically significant differences in depth-resolved perfusion rates in a human subject with various temperature exposure conditions.

  8. CT perfusion measurements of head and neck carcinoma from single section with largest tumor dimensions or average of multiple sections: Agreement between the two methods and effect on intra- and inter-observer agreement

    Energy Technology Data Exchange (ETDEWEB)

    Tawfik, Ahmed M., E-mail: ahm_m_tawfik@hotmail.com [Institut für Diagnostische und Interventionelle Radiologie, Klinikum der J.W.v. Goethe Universität Frankfurt am Main, Theodor-Stern-Kai 7 Frankfurt am Main 60590 (Germany); Diagnostic Radiology Department, Mansoura Faculty of Medicine, 62 Elgomhorya Street, Mansoura 35512 (Egypt); Nour-Eldin, Nour-Eldin A.; Naguib, Nagy N. [Institut für Diagnostische und Interventionelle Radiologie, Klinikum der J.W.v. Goethe Universität Frankfurt am Main, Theodor-Stern-Kai 7 Frankfurt am Main 60590 (Germany); Razek, Ahmed Abdel [Diagnostic Radiology Department, Mansoura Faculty of Medicine, 62 Elgomhorya Street, Mansoura 35512 (Egypt); Denewer, Adel T. [Surgical Oncology Department, Mansoura Oncology Centre, Mansoura Faculty of medicine (Egypt); Bisdas, Sotirios [Department of Neuroradiology, Eberhard Karls University, Tübingen (Germany); Vogl, Thomas J. [Institut für Diagnostische und Interventionelle Radiologie, Klinikum der J.W.v. Goethe Universität Frankfurt am Main, Theodor-Stern-Kai 7 Frankfurt am Main 60590 (Germany)

    2012-10-15

    Purpose: To evaluate the agreement between quantitative CT perfusion measurements of head and neck squamous cell carcinoma (SCC) obtained from single section with maximal tumor dimension and from average values of multiple sections, and to compare intra- and inter-observer agreement of the two methods. Methods: Perfusion was measured for 28 SCC cases using a region of interest (ROI) inserted in the single dynamic CT section showing maximal tumor dimension, then using average values of multiple ROIs inserted in all tumor-containing sections. Agreement between values of blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) calculated by the two methods was assessed. Intra-observer agreement was assessed by comparing repeated calculations done by the same radiologist using both methods after 2 months blinding period. Perfusion measurements were done by another radiologist independently to assess inter-observer agreement of both methods. Results: No significant differences were observed between the means of the 4 perfusion parameters calculated by both methods, all p values >0.05 The 95% limits of agreement between the two methods were (−33.9 to 43) ml/min/100 g for BF, (−2.5 to 2.8) ml/100 g for BV, (−4.9 to 3.9) s for MTT and (−17.5 to 18.6) ml/min/100 g for PS. Narrower limits of agreement were obtained using average of multiple sections than with single section denoting improved intra- and inter-observer agreement. Conclusion: Agreement between both methods is acceptable. Taking the average of multiple sections slightly improves intra- and inter-observer agreement.

  9. Brain perfusion heterogeneity measurement based on Random Walk algorithm: choice and influence of inner parameters.

    Science.gov (United States)

    Modzelewski, Romain; Janvresse, Elise; de la Rue, Thierry; Vera, Pierre

    2010-06-01

    A Random Walk (RW) algorithm was designed to quantify the level of diffuse heterogeneous perfusion in brain SPECT images in patients suffering from systemic brain disease or from drug-induced therapy. The goal of the present paper is to understand the behavior of the RW method on different kinds of images (extrinsic parameters) and also to understand how to choose the right parameters of the RW (intrinsic parameters) depending on the image characteristics (i.e. SPECT images). "Extrinsic parameters" are related to the image characteristics (level/size of defect and diffuse heterogeneity) and "intrinsic" parameters are related to the parameters of the method (number (N(rw)) and length of walk (L(rw)), temperature (T) and slowing parameter (S)). Two successive studies were conducted to test the influence of these parameters on the RW result. In the first study, calibrated checkerboard images are used to test the influence of "extrinsic parameters" (i.e. image characteristics) on the RW result (R-value). The R-value was tested as a function of (i) the size of black & white (B&W) squares simulating the size of a cortical defect, (ii) the intensity level gaps between the B&W squares simulating the intensity of the cortical defect and (iii) intensity (=variance) of noise, simulating the diffuse heterogeneity. The second study was constructed with simulated representative brain SPECT images, to test the "intrinsic" parameters. The R-value was tested regarding the influence of four parameters: S, T, N(rw) and L(rw). The third study is constructed so as to see if the classification by diffuse heterogeneity of real brain SPECT images is the same if it's made by senior clinicians or by RW algorithm. Study 1: the RW was strongly influenced by all the characteristics of the images. Moreover, these characteristics interact with each other. The RW is influenced most by diffuse heterogeneity, then by intensity and finally by the size of a defect. Study 2: N(rw) and L(rw) values of

  10. 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.

  11. 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.)

  12. CT Perfusion Characteristics Identify Metastatic Sites in Liver

    Directory of Open Access Journals (Sweden)

    Yuan Wang

    2015-01-01

    Full Text Available Tissue perfusion plays a critical role in oncology because growth and migration of cancerous cells require proliferation of new blood vessels through the process of tumor angiogenesis. Computed tomography (CT perfusion is an emerging functional imaging modality that measures tissue perfusion through dynamic CT scanning following intravenous administration of contrast medium. This noninvasive technique provides a quantitative basis for assessing tumor angiogenesis. CT perfusion has been utilized on a variety of organs including lung, prostate, liver, and brain, with promising results in cancer diagnosis, disease prognostication, prediction, and treatment monitoring. In this paper, we focus on assessing the extent to which CT perfusion characteristics can be used to discriminate liver metastases from neuroendocrine tumors from normal liver tissues. The neuroendocrine liver metastases were analyzed by distributed parameter modeling to yield tissue blood flow (BF, blood volume (BV, mean transit time (MTT, permeability (PS, and hepatic arterial fraction (HAF, for tumor and normal liver. The result reveals the potential of CT perfusion as a tool for constructing biomarkers from features of the hepatic vasculature for guiding cancer detection, prognostication, and treatment selection.

  13. CT Perfusion Characteristics Identify Metastatic Sites in Liver.

    Science.gov (United States)

    Wang, Yuan; Hobbs, Brian P; Ng, Chaan S

    2015-01-01

    Tissue perfusion plays a critical role in oncology because growth and migration of cancerous cells require proliferation of new blood vessels through the process of tumor angiogenesis. Computed tomography (CT) perfusion is an emerging functional imaging modality that measures tissue perfusion through dynamic CT scanning following intravenous administration of contrast medium. This noninvasive technique provides a quantitative basis for assessing tumor angiogenesis. CT perfusion has been utilized on a variety of organs including lung, prostate, liver, and brain, with promising results in cancer diagnosis, disease prognostication, prediction, and treatment monitoring. In this paper, we focus on assessing the extent to which CT perfusion characteristics can be used to discriminate liver metastases from neuroendocrine tumors from normal liver tissues. The neuroendocrine liver metastases were analyzed by distributed parameter modeling to yield tissue blood flow (BF), blood volume (BV), mean transit time (MTT), permeability (PS), and hepatic arterial fraction (HAF), for tumor and normal liver. The result reveals the potential of CT perfusion as a tool for constructing biomarkers from features of the hepatic vasculature for guiding cancer detection, prognostication, and treatment selection.

  14. 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)

  15. 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.

  16. Measurement of choroid plexus perfusion using dynamic susceptibility MR imaging: capillary permeability and age-related changes

    Energy Technology Data Exchange (ETDEWEB)

    Bouzerar, Roger; Chaarani, Bader; Baledent, Olivier [University Hospital, Image Processing Department, Amiens (France); Gondry-Jouet, Catherine [University Hospital, Radiology Department, Amiens (France); Zmudka, Jadwiga [University Hospital, Geriatric Unit, Amiens (France)

    2013-12-15

    The cerebrospinal fluid (CSF) plays a major role in the physiology of the central nervous system. The continuous turnover of CSF is mainly attributed to the highly vascularized choroid plexus (CP) located in the cerebral ventricles which represent a complex interface between blood and CSF. We propose a method for evaluating CP functionality in vivo using perfusion MR imaging and establish the age-related changes of associated parameters. Fifteen patients with small intracranial tumors were retrospectively studied. MR Imaging was performed on a 3T MR Scanner. Gradient-echo echo planar images were acquired after bolus injection of gadolinium-based contrast agent (CA). The software developed used the combined T1- and T2-effects. The decomposition of the relaxivity signals enables the calculation of the CP capillary permeability (K{sub 2}). The relative cerebral blood volume (rCBV), mean transit time (MTT), and signal slope decrease (SSD) were also calculated. The mean permeability K{sub 2} of the extracted CP was 0.033+/-0.18 s{sup -1}. K{sub 2} and SSD significantly decreased with subject's age whereas MTT significantly increased with subject's age. No significant correlation was found for age-related changes in rCBV and rCBF. The decrease in CP permeability is in line with the age-related changes in CSF secretion observed in animals. The MTT increase indicates significant structural changes corroborated by microscopy studies in animals or humans. Overall, DSC MR-perfusion enables an in vivo evaluation of the hemodynamic state of CP. Clinical applications such as neurodegenerative diseases could be considered thanks to specific functional studies of CP. (orig.)

  17. Early response evaluation using CT-perfusion one day after transarterial chemoembolization for HCC predicts treatment response and long-term disease control.

    Science.gov (United States)

    Tamandl, Dietmar; Waneck, Fredrik; Sieghart, Wolfgang; Unterhumer, Sylvia; Kölblinger, Claus; Baltzer, Pascal; Ba-Ssalamah, Ahmed; Loewe, Christian

    2017-05-01

    To determine the value of CT perfusion (CTP) for early response assessment after transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). Between April 2013 and April 2015, 41 HCC (16 patients) were included in this study. CT perfusion was performed before and one day after TACE. Blood flow (BF), blood volume (BV), time to start (TTS), arterial liver perfusion (ALP), portal liver perfusion (PVP) and hepatic perfusion index (HPI) were measured. Quantitative perfusion values before and after TACE were compared to the response assessed using mRECIST criteria six weeks after TACE and long-term outcome was assessed. Twenty-one lesions (51%) had complete remission (CR) and five (12%) had partial response (PR) six weeks after TACE. CTP parameters were significantly reduced after TACE in responders (PR, CR, pCT perfusion detects lesions with complete response one day after TACE, and is a feasible tool for early response assessment. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Validation of a laboratory method of measuring postpartum blood loss.

    Science.gov (United States)

    Chua, S; Ho, L M; Vanaja, K; Nordstrom, L; Roy, A C; Arulkumaran, S

    1998-01-01

    Laboratory methods give more accurate measurement of blood loss in the postpartum period than visual estimation. In order to evaluate a laboratory method used to quantify blood loss postpartum, blood lost at gynecological operations was collected in a measuring bottle. The measured amount of blood (50-1,000 ml) was then poured onto absorbent paper towels and sanitary pads, in order to mimic conditions when measuring blood loss in clinical trials in the postpartum period. The amount of blood absorbed onto the absorbent paper and sanitary pads was measured by a rapid method of automatic extraction and photometric measurement of alkaline hematin. The study shows that the method provides a reliable and accurate means of measuring blood loss. The error in each case was less than 10% with an intraclass correlation coefficient of almost 1.

  19. Signal quality measures for unsupervised blood pressure measurement

    International Nuclear Information System (INIS)

    Abdul Sukor, J; Redmond, S J; Lovell, N H; Chan, G S H

    2012-01-01

    Accurate systolic and diastolic pressure estimation, using automated blood pressure measurement, is difficult to achieve when the transduced signals are contaminated with noise or interference, such as movement artifact. This study presents an algorithm for automated signal quality assessment in blood pressure measurement by determining the feasibility of accurately detecting systolic and diastolic pressures when corrupted with various levels of movement artifact. The performance of the proposed algorithm is compared to a manually annotated reference scoring (RS). Based on visual representations and audible playback of Korotkoff sounds, the creation of the RS involved two experts identifying sections of the recorded sounds and annotating sections of noise contamination. The experts determined the systolic and diastolic pressure in 100 recorded Korotkoff sound recordings, using a simultaneous electrocardiograph as a reference signal. The recorded Korotkoff sounds were acquired from 25 healthy subjects (16 men and 9 women) with a total of four measurements per subject. Two of these measurements contained purposely induced noise artifact caused by subject movement. Morphological changes in the cuff pressure signal and the width of the Korotkoff pulse were extracted features which were believed to be correlated with the noise presence in the recorded Korotkoff sounds. Verification of reliable Korotkoff pulses was also performed using extracted features from the oscillometric waveform as recorded from the inflatable cuff. The time between an identified noise section and a verified Korotkoff pulse was the key feature used to determine the validity of possible systolic and diastolic pressures in noise contaminated Korotkoff sounds. The performance of the algorithm was assessed based on the ability to: verify if a signal was contaminated with any noise; the accuracy, sensitivity and specificity of this noise classification, and the systolic and diastolic pressure

  20. Correlation of cerebrovascular reserve as measured by acetazolamide-challenged perfusion CT with collateral circulation in unilateral high grade carotid stenosis

    International Nuclear Information System (INIS)

    Hong, Doran; Lee, Young Hen; Seo, Hyung Suk; Je, Bo Kyoung; Suh, Sang Il; Seol, Hae Young; Kim, Jung Hyuk; Lee, Nam Joon; Yang, Kyung Sook

    2014-01-01

    We correlated cerebrovascular reserve in unilateral high grade carotid artery stenosis or occlusion with a type of collateral circulation using acetazolamide-challenged perfusion CT (ACZ-PCT). Among the patients who underwent ACZ-PCT in our institution, we retrospectively selected the patients with unilateral high grade internal carotid artery or middle cerebral artery stenosis (> 70%) or occlusion; we verified the types of their dominant collateral circulation by digital subtraction angiography or 3T MR-angiography; first, the primary collaterals flow through the circle of Willis; second, the secondary collaterals that flow through the opthalmic artery, the basal artery or other external carotid artery. Using ACZ-PCT, we measured the difference in percentage change of cerebral blood flow of the stenotic hemisphere against contralateral normal hemisphere and compared cerebrovascular reserves of lesional hemisphere, according to the type of collaterals. A total of 28 patients were included. The percentage changes of cerebral blood flow were significantly lower in the stenotic hemisphere than the contralateral hemisphere (14.34 ± 36.43% and 34.53 ± 47.82%, p < 0.001), and in the hemisphere predominantly supplied by secondary collaterals than primary (7.03 ± 32.71% and 24.37 ± 42.03%, p < 0.05), respectively. Cerebrovascular reserves in the ipsilateral hemisphere predominantly supplied by secondary collaterals were more impaired than primary collaterals in patients with unilateral high grade carotid stenosis or occlusion.

  1. Blood Pressure Measurement: Clinic, Home, Ambulatory, and Beyond

    Science.gov (United States)

    Drawz, Paul E.; Abdalla, Mohamed; Rahman, Mahboob

    2014-01-01

    Blood pressure has traditionally been measured in the clinic setting using the auscultory method and a mercury sphygmomanometer. Technological advances have led to improvements in measuring clinic blood pressure and allowed for measuring blood pressures outside the clinic. This review outlines various methods for evaluating blood pressure and the clinical utility of each type of measurement. Home blood pressures and 24 hour ambulatory blood pressures have improved our ability to evaluate risk for target organ damage and hypertension related morbidity and mortality. Measuring home blood pressures may lead to more active participation in health care by patients and has the potential to improve blood pressure control. Ambulatory blood pressure monitoring enables the measuring nighttime blood pressures and diurnal changes, which may be the most accurate predictors of risk associated with elevated blood pressure. Additionally, reducing nighttime blood pressure is feasible and may be an important component of effective antihypertensive therapy. Finally, estimating central aortic pressures and pulse wave velocity are two of the newer methods for assessing blood pressure and hypertension related target organ damage. PMID:22521624

  2. Blood and dried blood spot telomere length measurement by qPCR: assay considerations.

    Directory of Open Access Journals (Sweden)

    DeAnna L Zanet

    Full Text Available Measurement of telomere length is crucial for the study of telomere maintenance and its role in molecular pathophysiology of diseases and in aging. Several methods are used to measure telomere length, the choice of which usually depends on the type and size of sample to be assayed, as well as cost and throughput considerations. The goal of this study was to investigate the factors that may influence the reliability of qPCR-based relative telomere length measurements in whole blood. Day to day intra-individual variability, types of blood anticoagulant, sample storage conditions, processing and site of blood draw were investigated. Two qPCR-based methods to measure telomere length (monoplex vs. multiplex were also investigated and showed a strong correlation between them. Freezing and thawing of the blood and storage of the blood at 4°C for up to 4 days did not affect telomere length values. Telomere lengths in dried blood spots were significantly higher than both whole blood and peripheral mononuclear blood cells, and were highly correlated with both. We found that telomere length measurements were significantly higher in dried blood spots collected directly from fingertip prick compared to dried blood spots prepared with anticoagulated whole blood collected from the finger, and non-blotted whole blood taken from both finger and arm venipuncture. This suggests that DNA from cells blotted on paper is not equivalent to that collected from venipuncture whole blood, and caution should be taken when comparing between blood sample types.

  3. Noninvasive, near infrared spectroscopic-measured muscle pH and PO2 indicate tissue perfusion for cardiac surgical patients undergoing cardiopulmonary bypass

    Science.gov (United States)

    Soller, Babs R.; Idwasi, Patrick O.; Balaguer, Jorge; Levin, Steven; Simsir, Sinan A.; Vander Salm, Thomas J.; Collette, Helen; Heard, Stephen O.

    2003-01-01

    OBJECTIVE: To determine whether near infrared spectroscopic measurement of tissue pH and Po2 has sufficient accuracy to assess variation in tissue perfusion resulting from changes in blood pressure and metabolic demand during cardiopulmonary bypass. DESIGN: Prospective clinical study. SETTING: Academic medical center. SUBJECTS: Eighteen elective cardiac surgical patients. INTERVENTION: Cardiac surgery under cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: A near infrared spectroscopic fiber optic probe was placed over the hypothenar eminence. Reference Po2 and pH sensors were inserted in the abductor digiti minimi (V). Data were collected every 30 secs during surgery and for 6 hrs following cardiopulmonary bypass. Calibration equations developed from one third of the data were used with the remaining data to investigate sensitivity of the near infrared spectroscopic measurement to physiologic changes resulting from cardiopulmonary bypass. Near infrared spectroscopic and reference pH and Po2 measurements were compared for each subject using standard error of prediction. Near infrared spectroscopic pH and Po2 at baseline were compared with values during cardiopulmonary bypass just before rewarming commenced (hypotensive, hypothermic), after rewarming (hypotensive, normothermic) just before discontinuation of cardiopulmonary bypass, and at 6 hrs following cardiopulmonary bypass (normotensive, normothermic) using mixed-model analysis of variance. Near infrared spectroscopic pH and Po2 were well correlated with the invasive measurement of pH (R2 =.84) and Po2 (R 2 =.66) with an average standard error of prediction of 0.022 +/- 0.008 pH units and 6 +/- 3 mm Hg, respectively. The average difference between the invasive and near infrared spectroscopic measurement was near zero for both the pH and Po2 measurements. Near infrared spectroscopic Po2 significantly decreased 50% on initiation of cardiopulmonary bypass and remained depressed throughout the bypass and

  4. Subtracted dynamic MR perfusion source images (sMRP-SI) provide collateral blood flow assessment in MCA occlusions and predict tissue fate

    Energy Technology Data Exchange (ETDEWEB)

    Villringer, Kersten; Serrano-Sandoval, Rafael; Galinovic, Ivana; Ostwaldt, Ann-Christin; Brunecker, Peter; Fiebach, Jochen B. [Charite-Universitaetsmedizin, Academic Neuroradiology, Center for Stroke Research (CSB), Berlin (Germany); Grittner, Ulrike [Charite, Universitaetsmedizin Berlin, Center for Stroke Research, Berlin (Germany); Charite, Department for Biostatistics and Clinical Epidemiology, Berlin (Germany); Schneider, Alice [Charite, Universitaetsmedizin Berlin, Center for Stroke Research, Berlin (Germany); Rocco, Andrea [Charite, Department of Neurology and Center for Stroke Research, Berlin (Germany)

    2016-05-15

    Collateral blood flow is accepted as a predictive factor of tissue fate in ischemic stroke. Thus, we aimed to evaluate a new method derived from MR perfusion source images to assess collateral flow in patients with ICA/MCA occlusions. A total of 132 patients of the prospective 1000+ study were examined. MR perfusion source images were assessed according to Δimg{sub n} = img{sub n} + 1 - img{sub n} - 1 using the five-grade Higashida collateral flow rating system. Higashida scores were correlated to mismatch (MM) volume, mismatch ratio, day 6 FLAIR lesion volumes and day 90 mRS. Patients with Higashida scores 3 and 4 had significantly lower admission NIHSS, smaller FLAIR day 6 lesion volumes (p < 0.001) and higher rates of better long-term outcome (mRS 0-2, p = 0.002). There was a linear trend for the association of Higashida grade 1 (p = 0.002) and 2 (p = 0.001) with unfavourable outcome (day 90 mRS 3-6), but no significant association was found for MM volume, MM ratio and day 90 mRS. Inter-rater agreement was 0.58 (95 % CI 0.43-0.73) on day 1, 0.70 (95 % CI 0.58-0.81) on day 2. sMRP-SI Higashida score offers a non-invasive collateral vessel and tissue perfusion assessment of ischemic tissue. The predictive value of Higashida rating proved superior to MM with regard to day 90 mRS. (orig.)

  5. Subtracted dynamic MR perfusion source images (sMRP-SI) provide collateral blood flow assessment in MCA occlusions and predict tissue fate

    International Nuclear Information System (INIS)

    Villringer, Kersten; Serrano-Sandoval, Rafael; Galinovic, Ivana; Ostwaldt, Ann-Christin; Brunecker, Peter; Fiebach, Jochen B.; Grittner, Ulrike; Schneider, Alice; Rocco, Andrea

    2016-01-01

    Collateral blood flow is accepted as a predictive factor of tissue fate in ischemic stroke. Thus, we aimed to evaluate a new method derived from MR perfusion source images to assess collateral flow in patients with ICA/MCA occlusions. A total of 132 patients of the prospective 1000+ study were examined. MR perfusion source images were assessed according to Δimg n = img n + 1 - img n - 1 using the five-grade Higashida collateral flow rating system. Higashida scores were correlated to mismatch (MM) volume, mismatch ratio, day 6 FLAIR lesion volumes and day 90 mRS. Patients with Higashida scores 3 and 4 had significantly lower admission NIHSS, smaller FLAIR day 6 lesion volumes (p < 0.001) and higher rates of better long-term outcome (mRS 0-2, p = 0.002). There was a linear trend for the association of Higashida grade 1 (p = 0.002) and 2 (p = 0.001) with unfavourable outcome (day 90 mRS 3-6), but no significant association was found for MM volume, MM ratio and day 90 mRS. Inter-rater agreement was 0.58 (95 % CI 0.43-0.73) on day 1, 0.70 (95 % CI 0.58-0.81) on day 2. sMRP-SI Higashida score offers a non-invasive collateral vessel and tissue perfusion assessment of ischemic tissue. The predictive value of Higashida rating proved superior to MM with regard to day 90 mRS. (orig.)

  6. [An integrated system of blood pressure measurement with bluetooth communication].

    Science.gov (United States)

    Wang, Wei; Wang, Jing; Sun, Hongyang; Xu, Zuyang; Chai, Xinyu

    2012-07-01

    The development of the integrated blood pressure system with bluetooth communication function is introduced. Experimental results show that the system can complete blood pressure measurement and data transmission wireless effectively, which can be used in m-Health in future.

  7. 3D discrete angiogenesis dynamic model and stochastic simulation for the assessment of blood perfusion coefficient and impact on heat transfer between nanoparticles and malignant tumors.

    Science.gov (United States)

    Yifat, Jonathan; Gannot, Israel

    2015-03-01

    Early detection of malignant tumors plays a crucial role in the survivability chances of the patient. Therefore, new and innovative tumor detection methods are constantly searched for. Tumor-specific magnetic-core nano-particles can be used with an alternating magnetic field to detect and treat tumors by hyperthermia. For the analysis of the method effectiveness, the bio-heat transfer between the nanoparticles and the tissue must be carefully studied. Heat diffusion in biological tissue is usually analyzed using the Pennes Bio-Heat Equation, where blood perfusion plays an important role. Malignant tumors are known to initiate an angiogenesis process, where endothelial cell migration from neighboring vasculature eventually leads to the formation of a thick blood capillary network around them. This process allows the tumor to receive its extensive nutrition demands and evolve into a more progressive and potentially fatal tumor. In order to assess the effect of angiogenesis on the bio-heat transfer problem, we have developed a discrete stochastic 3D model & simulation of tumor-induced angiogenesis. The model elaborates other angiogenesis models by providing high resolution 3D stochastic simulation, capturing of fine angiogenesis morphological features, effects of dynamic sprout thickness functions, and stochastic parent vessel generator. We show that the angiogenesis realizations produced are well suited for numerical bio-heat transfer analysis. Statistical study on the angiogenesis characteristics was derived using Monte Carlo simulations. According to the statistical analysis, we provide analytical expression for the blood perfusion coefficient in the Pennes equation, as a function of several parameters. This updated form of the Pennes equation could be used for numerical and analytical analyses of the proposed detection and treatment method. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. A comparative study of perfusion CT and 99mTc-Hmpao spect measurement to assess cerebrovascular reserve capacity in patients with internal carotid artery occlusion

    Directory of Open Access Journals (Sweden)

    Eicker S

    2011-11-01

    Full Text Available Abstract Background and purpose Patients with internal carotid artery (ICA occlusion can demonstrate impaired cerebral vascular reserve (CVR. The detection of CVR using single photon emission CT (SPECT is nowadays widely accepted as a predictor in the diagnostic pathway in patients considered for cerebral revascularization. Recently perfusion CT (PCT gained widely acceptance in stroke imaging The present study was aimed at comparing the results of perfusion CT (PCT and 99mTc-HMPAO SPECT with acetazolamide challenge in patients with ICA occlusion. Methods 13 patients were included in the prospective evaluation. Both PCT and 99mTc-HMPAO SPECT were performed before and after the administration of acetazolamide. In detail, regional cerebral blood flow (rCBF, regional cerebral blood volume (rCBV, adapted time to peak (Tmax and mean transit times (MTT were compared with SPECT data. Results 99mTc-HMPAO SPECT demonstrated an impairment of CVR in six patients. A preserved CVR was present in seven patients. All patients with impaired CVR proven by SPECT had a delayed MTT (mean +2.98 s and a delayed Tmax (mean + 5.9 s, (both p Conclusion The prospective study demonstrated a highly significant correlation of perfusion parameters as' detected by 99mTc-HMPAO SPECT and the Tmax as detected by PCT in patients with ICA occlusion. Therefore this easy-to-perform technique seems to be an adequate method for the evaluation of cerebral perfusion in patients with ICA occlusion.

  9. Auscultatory versus oscillometric measurement of blood pressure in octogenarians

    DEFF Research Database (Denmark)

    Rosholm, Jens-Ulrik; Pedersen, Sidsel Arnspang; Matzen, Lars

    2012-01-01

    Auscultatory measurement using a sphygmomanometer has been the predominant method for clinical estimation of blood pressure, but it is now rapidly being replaced by oscillometric measurement.......Auscultatory measurement using a sphygmomanometer has been the predominant method for clinical estimation of blood pressure, but it is now rapidly being replaced by oscillometric measurement....

  10. [Measurement of blood pressure variability and the clinical value].

    Science.gov (United States)

    Kékes, Ede; Kiss, István

    2014-10-19

    Authors have collected and analyzed literature data on blood pressure variability. They present the methods of blood pressure variability measurement, clinical value and relationships with target organ damages and risk of presence of cardiovascular events. They collect data about the prognostic value of blood pressure variability and the effects of different antihypertensive drugs on blood pressure variability. They underline that in addition to reduction of blood pressure to target value, it is essential to influence blood pressure fluctuation and decrease blood pressure variability, because blood pressure fluctuation presents a major threat for the hypertensive subjects. Data from national studies are also presented. They welcome that measurement of blood pressure variability has been included in international guidelines.

  11. Metrics of quality care in veterans: correlation between primary-care performance measures and inappropriate myocardial perfusion imaging.

    Science.gov (United States)

    Winchester, David E; Kitchen, Andrew; Brandt, John C; Dusaj, Raman S; Virani, Salim S; Bradley, Steven M; Shaw, Leslee J; Beyth, Rebecca J

    2015-04-01

    Approximately 10% to 20% of myocardial perfusion imaging (MPI) tests are inappropriate based on professional-society recommendations. The correlation between inappropriate MPI and quality care metrics is not known. Inappropriate MPI will be associated with low achievement of quality care metrics. We conducted a retrospective cross-sectional investigation at a single Veterans Affairs medical center. Myocardial perfusion imaging tests ordered by primary-care clinicians between December 2010 and July 2011 were assessed for appropriateness (by 2009 criteria). Using documentation of the clinical encounter where MPI was ordered, we determined how often quality care metrics were achieved. Among 516 MPI patients, 52 (10.1%) were inappropriate and 464 (89.9%) were not inappropriate (either appropriate or uncertain). Hypertension (82.2%), diabetes mellitus (41.3%), and coronary artery disease (41.1%) were common. Glycated hemoglobin levels were lower in the inappropriate MPI cohort (6.6% vs 7.5%; P = 0.04). No difference was observed in the proportion with goal hemoglobin (62.5% vs 46.3% for appropriate/uncertain; P = 0.258). Systolic blood pressure was not different (132 mm Hg vs 135 mm Hg; P = 0.34). Achievement of several other categorical quality metrics was low in both cohorts and no differences were observed. More than 90% of clinicians documented a plan to achieve most metrics. Inappropriate MPI is not associated with performance on metrics of quality care. If an association exists, it may be between inappropriate MPI and overly aggressive care. Most clinicians document a plan of care to address failure of quality metrics, suggesting awareness of the problem. © 2015 Wiley Periodicals, Inc.

  12. Intra- and multicenter reproducibility of pulsed, continuous and pseudo-continuous arterial spin labeling methods for measuring cerebral perfusion.

    Science.gov (United States)

    Gevers, Sanna; van Osch, Matthias J; Bokkers, Reinoud P H; Kies, Dennis A; Teeuwisse, Wouter M; Majoie, Charles B; Hendrikse, Jeroen; Nederveen, Aart J

    2011-08-01

    Intra- and multicenter reproducibility of currently used arterial spin labeling (ASL) methods were assessed at three imaging centers in the Netherlands, equipped with Philips 3TMR scanners. Six healthy participants were scanned twice at each site. The imaging protocol consisted of continuous ASL (CASL), pseudo-continuous ASL (p-CASL) with and without background suppression, pulsed ASL (PASL) with single and multiple inversion times (TIs), and selective ASL for segmentation. Reproducibility was expressed in terms of the coefficient of repeatability and the repeatability index. Voxelwise analysis of variance was performed, yielding brain maps that reflected regional variability. Intra- and multicenter reproducibility were comparable for all methods, except for single TI PASL, with better intracenter reproducibility (F-test of equality of two variances, Pfeeding arteries within sessions and in gray matter between sessions. On the basis of the results of this study, one could consider the use of reference values in clinical routine, with whole-brain p-CASL perfusion varying <20% over repeated measurements within the same individuals considered to be normal. Knowledge on regional variability allows for the use of perfusion-weighted images in the assessment of local cerebral pathology.

  13. Pulmonary blood volume measured by RI angiocardiography

    International Nuclear Information System (INIS)

    Ono, Kazuo

    1982-01-01

    RI angiocardiography (RACG) was performed in 81 patients with heart disease without congestive heart failure at the time, and the results were compared between the groups with mitral valve disease and other diseases. Cardiac output (CO) and pulmonary mean transit time (PMTT) were compared with the results from the dye dilution method in the same patients. PMTT directly measured by RACG was also compared with the peak to peak time (P-PT). P-PT was expressed as the distance from the right to the left peak time in radiocardiography (RCG). There were good correlations between the CO and PMTT obtained from the RI method and those of the dye dilution method (r = 0.90, r = 0.84). The ralationship between PMTT and P-PT in mitral valve disease was different from that of other diseases. The average value of PMTT was 5.2 +- 1.0 seconds, and pulmonary blood volume (PBV) was 315 +- 57 ml/m 2 in the control group. The PBV values were markedly increased in patients with mitral stenosis (558 +- 132 ml/m 2 ) and mitral regurgitation (444 +- 119 ml/m 2 ), and were slightly increased in aortic valve disease, congenital shunt disease and cardiomyopathy. The patients with ischemic heart disease had normal PBV. In mitral valve disease, the direct method using PMTT of RACG is more accurate than the presumption method using P-PT of RCG. The determination of PBV by this method is very important to observe hemodynamic states in mitral valve disease. (J.P.N.)

  14. Role of cerebral blood volume changes in brain specific-gravity measurements

    International Nuclear Information System (INIS)

    Picozzi, P.; Todd, N.V.; Crockard, A.H.

    1985-01-01

    Cerebral blood volume (CBV) was calculated in gerbils from specific-gravity (SG) changes between normal and saline-perfused brains. Furthermore, changes in CBV were investigated during ischemia using carbon-14-labeled dextran (MW 70,000) as an intravascular marker. Both data were used to evaluate the possible error due to a change in CBV on the measurement of ischemic brain edema by the SG method. The methodological error found was 0.0004 for a 100% CBV change. This error is insignificant, being less than the standard deviation in the SG measured for the gerbil cortex. Thus, CBV changes are not responsible for the SG variations observed during the first phase of ischemia. These variations are better explained as an increase of brain water content during ischemia

  15. SU-F-R-34: Quantitative Perfusion Measurement in Rectal Cancer Using Three Different Pharmacokinetic Models: Implications for Prospective Study Design

    Energy Technology Data Exchange (ETDEWEB)

    Nie, K; Yue, N; Jabbour, S; Kim, S [Rutgers-Cancer Institute of New Jersey, Rutgers-Robert Wood Johnson Medical, New Brunswick, NJ (United States); Mao, T; Shi, L; Hu, X; Qian, L; Sun, X; Niu, T [Sir Run Run Shaw Hospital, Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang (China)

    2016-06-15

    Purpose: To compare three different pharmacokinetic models for analysis of dynamic-contrast-enhanced (DCE)-CT data with respect to different acquisition times and location of region of interest. Methods: Eight rectal cancer patients with pre-treatment DCE-CTs were included. The dynamic sequence started 4–10seconds(s) after the injection of contrast agent. The scan included a 110s acquisition with intervals of 40×1s+15×3s+4×6s. An experienced oncologist outlined the tumor region. Hotspots with top-5%-enhancement were also identified. Pharmacokinetic analysis was performed using three different models: deconvolution method, Patlak model, and modified Toft’s model. Perfusion parameters as blood flow (BF), blood volume (BV), mean transit time (MTT), permeability-surface-area-product (PS), volume transfer constant (Ktrans), and flux rate constant (Kep), were compared with respect to different acquisition times of 45s, 65s, 85s and 105s. Both hotspot and whole-volume variances were also assessed. The differences were compared using the Wilcoxon matched-pairs test and Bland-Altman plots. Results: Moderate correlation was observed for various perfusion parameters (r=0.56–0.72, p<0.0001) but the Wilcoxon test revealed a significant difference among the three models (P < .001). Significant differences in PS were noted between acquisitions of 45s versus longer time of 85s or 105s (p<0.05) using Patlak but not with the deconvolution method. In addition, measurements varied substantially between whole-volume vs. hotspot analysis. Conclusion: The radiation dose of DCE-CT was on average 1.5 times of an abdomen/pelvic CT, which is not insubstantial. To take the DCE-CT forward as a biomarker in oncology, prospective studies should be carefully designed with the optimal image acquisition and analysis technique. Our study suggested that: (1) different kinetic models are not interchangeable; (2) a 45s acquisition might not be sufficient for reliable permeability measurement

  16. 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

  17. A feasibility study on model-based evaluation of kidney perfusion measured by means of FAIR prepared true-FISP arterial spin labeling (ASL) on a 3-T MR scanner.

    Science.gov (United States)

    Kiefer, Claus; Schroth, Gerhard; Gralla, Jan; Diehm, Nico; Baumgartner, Iris; Husmann, Mare

    2009-01-01

    A feasibility study on measuring kidney perfusion by a contrast-free magnetic resonance (MR) imaging technique is presented. A flow-sensitive alternating inversion recovery (FAIR) prepared true fast imaging with steady-state precession (TrueFISP) arterial spin labeling sequence was used on a 3.0-T MR-scanner. The basis for quantification is a two-compartment exchange model proposed by Parkes that corrects for diverse assumptions in single-compartment standard models. Eleven healthy volunteers (mean age, 42.3 years; range 24-55) were examined. The calculated mean renal blood flow values for the exchange model (109 +/- 5 [medulla] and 245 +/- 11 [cortex] ml/min - 100 g) are in good agreement with the literature. Most important, the two-compartment exchange model exhibits a stabilizing effect on the evaluation of perfusion values if the finite permeability of the vessel wall and the venous outflow (fast solution) are considered: the values for the one-compartment standard model were 93 +/- 18 (medulla) and 208 +/- 37 (cortex) ml/min - 100 g. This improvement will increase the accuracy of contrast-free imaging of kidney perfusion in treatment renovascular disease.

  18. Changes of arterial blood flow patterns by patients' posture during hepatic arterial infusion chemotherapy assessed by [sup 99m]Tc-MAA perfusion scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Sone, Yasuhiro; Arai, Yasuaki; Mukaijo, Toshifumi; Nakatsuka, Atsuhiro; Sasaki, Fumio; Kido, Choichiro (Aichi Cancer Center, Nagoya (Japan))

    1993-11-01

    Hepatic arterial perfusion scintigraphy (HAPS) with [sup 99m]Tc-macroaggregated albumin (MAA) was performed to reveal the effect of patients' posture for the arterial blood flow patterns in hepatic arterial infusion (HAI) chemotherapy. Twenty patients with liver metastases having the percutaneously implanted catheter into the hepatic artery underwent HAPS following administration of [sup 99m]Tc-MAA at the supine and the upright position under one week interval. Ten ml of the saline with radionuclide was injected at a rate of one ml per minute. Acquired two images at the different position of each patient were compared and grouped into three classes: similar, slightly different and different. Of 20 patients, 6 (30%) were judged as similar, 8 (40%) as slightly different, and 6 (30%) as different. These results suggest that the drug distribution can change by patients' posture in case of the slow rate HAI performed with continuous infusion pump. (author).

  19. Skin perfusion pressure on the legs measured as the external pressure required for skin reddening after blanching

    DEFF Research Database (Denmark)

    Holstein, P; Nielsen, P.E.; Lund, P

    1980-01-01

    the skin blood flow cessation external pressure (FCEP) was recorded using intra-dermal [131I-]-antipyrine mixed with histamine in estimating the skin blood flow. The external pressure was measured with an airfilled plastic cushion connected to a mercury manometer. Over a wide range of pressures as obtained...

  20. Effects of resting state condition on reliability, trait specificity, and network connectivity of brain function measured with arterial spin labeled perfusion MRI.

    Science.gov (United States)

    Li, Zhengjun; Vidorreta, Marta; Katchmar, Natalie; Alsop, David C; Wolf, Daniel H; Detre, John A

    2018-06-01

    Resting state fMRI (rs-fMRI) provides imaging biomarkers of task-independent brain function that can be associated with clinical variables or modulated by interventions such as behavioral training or pharmacological manipulations. These biomarkers include time-averaged regional brain function as manifested by regional cerebral blood flow (CBF) measured using arterial spin labeled (ASL) perfusion MRI and correlated temporal fluctuations of function across brain networks with either ASL or blood oxygenation level dependent (BOLD) fMRI. Resting-state studies are typically carried out using just one of several prescribed state conditions such as eyes closed (EC), eyes open (EO), or visual fixation on a cross-hair (FIX), which may affect the reliability and specificity of rs-fMRI. In this study, we collected test-retest ASL MRI data during 4 resting-state task conditions: EC, EO, FIX and PVT (low-frequency psychomotor vigilance task), and examined the effects of these task conditions on reliability and reproducibility as well as trait specificity of regional brain function. We also acquired resting-state BOLD fMRI under FIX and compared the network connectivity reliabilities between the four ASL conditions and the BOLD FIX condition. For resting-state ASL data, EC provided the highest CBF reliability, reproducibility, trait specificity, and network connectivity reliability, followed by EO, while FIX was lowest on all of these measures. PVT demonstrated lower CBF reliability, reproducibility and trait specificity than EO and EC. Overall network connectivity reliability was comparable between ASL and BOLD. Our findings confirm ASL CBF as a reliable, stable, and consistent measure of resting-state regional brain function and support the use of EC or EO over FIX and PVT as the resting-state condition. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Electroencephalography reveals lower regional blood perfusion and atrophy of the temporoparietal network associated with memory deficits and hippocampal volume reduction in mild cognitive impairment due to Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Moretti DV

    2015-02-01

    Full Text Available Davide Vito MorettiNational Institute for the research and cure of Alzheimer’s disease, S. John of God, Fatebenefratelli, Brescia, Italy Background: An increased electroencephalographic (EEG upper/lower alpha power ratio has been associated with less regional blood perfusion, atrophy of the temporoparietal region of the brain, and reduction of hippocampal volume in subjects affected by mild cognitive impairment due to Alzheimer’s disease as compared with subjects who do not develop the disease. Moreover, EEG theta frequency activity is quite different in these groups. This study investigated the correlation between biomarkers and memory performance.Methods: EEG α3/α2 power ratio and cortical thickness were computed in 74 adult subjects with prodromal Alzheimer’s disease. Twenty of these subjects also underwent assessment of blood perfusion by single-photon emission computed tomography (SPECT. Pearson’s r was used to assess the correlation between cortical thinning, brain perfusion, and memory impairment.Results: In the higher α3/α2 frequency power ratio group, greater cortical atrophy and lower regional perfusion in the temporoparietal cortex was correlated with an increase in EEG theta frequency. Memory impairment was more pronounced in the magnetic resonance imaging group and SPECT groups.Conclusion: A high EEG upper/low alpha power ratio was associated with cortical thinning and less perfusion in the temporoparietal area. Moreover, atrophy and less regional perfusion were significantly correlated with memory impairment in subjects with prodromal Alzheimer’s disease. The EEG upper/lower alpha frequency power ratio could be useful for identifying individuals at risk for progression to Alzheimer’s dementia and may be of value in the clinical context.Keywords: electroencephalography, perfusion, atrophy, temporoparietal network, memory deficits, hippocampal volume, mild cognitive impairment, Alzheimer’s disease

  2. Clinical value of blood pressure measurement in the community pharmacy.

    Science.gov (United States)

    Sabater-Hernández, Daniel; Azpilicueta, Inés; Sánchez-Villegas, Pablo; Amariles, Pedro; Baena, María I; Faus, María J

    2010-10-01

    To investigate whether the measurement of blood pressure in the community pharmacy is a valuable method to diagnose hypertension, to assess the need and the effectiveness of anti-hypertensive treatments, or, in general, to make clinical decisions. Information has been extracted from articles published in English and in Spanish, from January 1989 to December 2009, in indexed magazines in MEDLINE and EMBASE. To perform the search, multiple and specified terms related to the community pharmacy setting, to blood pressure measurement and to the comparison and agreement between blood pressure measurement methods were used. Selected articles were those that: (1) compared and/or measured the agreement (concordance) between community pharmacy blood pressure measurements obtained in repeated occasions, or (2) compared and/or measured the agreement between the community pharmacy blood pressure measurement method and other measurement methods used in clinical practice for decision-making purposes: blood pressure measurement by a physician, by a nurse and home or ambulatory blood pressure monitoring. Articles were included and analyzed by two investigators independently, who essentially extracted the main results of the manuscripts, emphasizing the assessment of the blood pressure measurement methods used and the completed statistical analysis. Only three studies comparing the community pharmacy blood pressure measurement method with other methods and one comparing repeated measurements of community pharmacy blood pressure were found. Moreover, these works present significant biases and limitations, both in terms of method and statistical analysis, which make difficult to draw consistent conclusions. Further research of high quality is needed, which results can guide the clinical decision-making based on the community pharmacy blood pressure measurement method.

  3. : Myocardial Perfusion

    OpenAIRE

    Dacher, Jean-Nicolas; Lefebvre, V.; Dubourg, Bernard; Deux, Jean-François; Caudron, Jérôme

    2013-01-01

    International audience; The analysis of myocardial perfusion is a key step in the cardiac MRI examination. In routine work, this exploration carried out at rest is based on the qualitative first pass study of gadolinium with an ECG-triggered saturation recovery bFFE sequence. In view of recent knowledge, the analysis of the myocardial perfusion under vasodilator stress may be carried out by scintigraphy or MRI, the latter benefiting from the absence of exposure to ionizing rays and a lower co...

  4. Alterations of the Blood-Brain Barrier and Regional Perfusion in Tumor Development: MRI Insights from a Rat C6 Glioma Model.

    Directory of Open Access Journals (Sweden)

    Monika Huhndorf

    Full Text Available Angiogenesis and anti-angiogenetic medications play an important role in progression and therapy of glioblastoma. In this context, in vivo characterization of the blood-brain-barrier and tumor vascularization may be important for individual prognosis and therapy optimization.We analyzed perfusion and capillary permeability of C6-gliomas in rats at different stages of tumor-growth by contrast enhanced MRI and dynamic susceptibility contrast (DSC MRI at 7 Tesla. The analyses included maps of relative cerebral blood volume (CBV and signal recovery derived from DSC data over a time period of up to 35 days after tumor cell injections.In all rats tumor progression was accompanied by temporal and spatial changes in CBV and capillary permeability. A leakage of the blood-brain barrier (slow contrast enhancement was observed as soon as the tumor became detectable on T2-weighted images. Interestingly, areas of strong capillary permeability (fast signal enhancement were predominantly localized in the center of the tumor. In contrast, the tumor rim was dominated by an increased CBV and showed the highest vessel density compared to the tumor center and the contralateral hemisphere as confirmed by histology.Substantial regional differences in the tumor highlight the importance of parameter maps in contrast or in addition to region-of-interest analyses. The data vividly illustrate how MRI including contrast-enhanced and DSC-MRI may contribute to a better understanding of tumor development.

  5. 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...

  6. Blood volume measurements in gopher snakes, using autologous 51Cr-labeled red blood cells.

    Science.gov (United States)

    Smeller, J M; Bush, M; Seal, U S

    1978-02-01

    Blood volume determinations were performed in 5 anesthetized gopher snakes (Pituophis melanoleucus catenifer) by means of a 51Cr-labeled red blood cell (RBC) method. The mean blood volume was 52.8 ml/kg of body weight (+/- 6.21 SE). Previous blood volume measurements have not been reported for this species. The RBC survival rate was estimated to be greater than 660 days. The RBC survival rate is long, but it cannot be determined accurately by this method.

  7. Blood pressure and anthropometric measurements in healthy ...

    African Journals Online (AJOL)

    Treatment of High Blood Pressure (JNC-7),8 with the subjects sitting quietly and the right arm on a table at the level of the heart. An appropriately sized cuff, covering at least two-thirds of the upper arm with the lower border not less than 2.5 cm from the cubital fossa, was applied after restricting clothing had been removed.

  8. Colour measurement and white blood cell recognition

    CERN Document Server

    Gelsema, E S

    1972-01-01

    As a part of a collaboration with NEMCH aimed at the automation of the differential white blood cell count, studies have been made of the different possibilities for using colour to help in the recognition process. Results are presented comparing data obtained with a microspectrophotometer and with a simulated three-colour scanner.

  9. Theoretical considerations in measurement of time discrepancies between input and myocardial time-signal intensity curves in estimates of regional myocardial perfusion with first-pass contrast-enhanced MRI.

    Science.gov (United States)

    Natsume, Takahiro; Ishida, Masaki; Kitagawa, Kakuya; Nagata, Motonori; Sakuma, Hajime; Ichihara, Takashi

    2015-11-01

    The purpose of this study was to develop a method to determine time discrepancies between input and myocardial time-signal intensity (TSI) curves for accurate estimation of myocardial perfusion with first-pass contrast-enhanced MRI. Estimation of myocardial perfusion with contrast-enhanced MRI using kinetic models requires faithful recording of contrast content in the blood and myocardium. Typically, the arterial input function (AIF) is obtained by setting a region of interest in the left ventricular cavity. However, there is a small delay between the AIF and the myocardial curves, and such time discrepancies can lead to errors in flow estimation using Patlak plot analysis. In this study, the time discrepancies between the arterial TSI curve and the myocardial tissue TSI curve were estimated based on the compartment model. In the early phase after the arrival of the contrast agent in the myocardium, the relationship between rate constant K1 and the concentrations of Gd-DTPA contrast agent in the myocardium and arterial blood (LV blood) can be described by the equation K1={dCmyo(tpeak)/dt}/Ca(tpeak), where Cmyo(t) and Ca(t) are the relative concentrations of Gd-DTPA contrast agent in the myocardium and in the LV blood, respectively, and tpeak is the time corresponding to the peak of Ca(t). In the ideal case, the time corresponding to the maximum upslope of Cmyo(t), tmax, is equal to tpeak. In practice, however, there is a small difference in the arrival times of the contrast agent into the LV and into the myocardium. This difference was estimated to correspond to the difference between tpeak and tmax. The magnitudes of such time discrepancies and the effectiveness of the correction for these time discrepancies were measured in 18 subjects who underwent myocardial perfusion MRI under rest and stress conditions. The effects of the time discrepancies could be corrected effectively in the myocardial perfusion estimates. Copyright © 2015 Elsevier Inc. All rights

  10. Measurement of canine pancreatic perfusion using dynamic computed tomography: Influence of input-output vessels on deconvolution and maximum slope methods

    Energy Technology Data Exchange (ETDEWEB)

    Kishimoto, Miori, E-mail: miori@mx6.et.tiki.ne.jp [Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-11 Inada-cho, Obihiro 080-8555 (Japan); Tsuji, Yoshihisa, E-mail: y.tsuji@extra.ocn.ne.jp [Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Shogoinkawara-cho 54, Sakyo-ku 606-8507 (Japan); Katabami, Nana; Shimizu, Junichiro; Lee, Ki-Ja [Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-11 Inada-cho, Obihiro 080-8555 (Japan); Iwasaki, Toshiroh [Department of Veterinary Internal Medicine, Tokyo University of Agriculture and Technology, Saiwai-cho, 3-5-8, Fuchu 183-8509 (Japan); Miyake, Yoh-Ichi [Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-11 Inada-cho, Obihiro 080-8555 (Japan); Yazumi, Shujiro [Digestive Disease Center, Kitano Hospital, 2-4-20 Ougi-machi, Kita-ku, Osaka 530-8480 (Japan); Chiba, Tsutomu [Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Shogoinkawara-cho 54, Sakyo-ku 606-8507 (Japan); Yamada, Kazutaka, E-mail: kyamada@obihiro.ac.jp [Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-11 Inada-cho, Obihiro 080-8555 (Japan)

    2011-01-15

    Objective: We investigated whether the prerequisite of the maximum slope and deconvolution methods are satisfied in pancreatic perfusion CT and whether the measured parameters between these algorithms are correlated. Methods: We examined nine beagles injected with iohexol (200 mgI kg{sup -1}) at 5.0 ml s{sup -1}. The abdominal aorta and splenic and celiac arteries were selected as the input arteries and the splenic vein, the output veins. For the maximum slope method, we determined the arterial contrast volume of each artery by measuring the area under the curve (AUC) and compared the peak enhancement time in the pancreas with the contrast appearance time in the splenic vein. For the deconvolution method, the artery-to-vein collection rate of contrast medium was calculated. We calculated the pancreatic tissue blood flow (TBF), tissue blood volume (TBV), and mean transit time (MTT) using both algorithms and investigated their correlation based on vessel selection. Results: The artery AUC significantly decreased as it neared the pancreas (P < 0.01). In all cases, the peak time of the pancreas (11.5 {+-} 1.6) was shorter than the appearance time (14.1 {+-} 1.6) in the splenic vein. The splenic artery-vein combination exhibited the highest collection rate (91.1%) and was the only combination that was significantly correlated between TBF, TBV, and MTT in both algorithms. Conclusion: Selection of a vessel nearest to the pancreas is considered as a more appropriate prerequisite. Therefore, vessel selection is important in comparison of the semi-quantitative parameters obtained by different algorithms.

  11. Quantitative perfusion computed tomography measurements of cerebral hemodynamics: Correlation with digital subtraction angiography identified primary and secondary cerebral collaterals in internal carotid artery occlusive disease

    International Nuclear Information System (INIS)

    Cheng Xiaoqing; Tian Jianming; Zuo Changjing; Liu Jia; Zhang Qi; Lu Guangming

    2012-01-01

    Background: The aim of the present study was to assess hemodynamic variations in symptomatic unilateral internal carotid artery occlusion (ICAO) patients with primary collateral flow via circle of Willis or secondary collateral flow via ophthalmic artery and/or leptomeningeal collaterals. Methods: Thirty-eight patients with a symptomatic unilateral ICAO were enrolled in the study. Based on digital subtraction angiography (DSA) findings, patients were classified into 2 groups: primary collateral (n = 14) and secondary collateral (n = 24) groups. Collateral flow hemodynamics were investigated with perfusion computed tomography (PCT) by measuring the cerebral blood flow (CBF), cerebral blood volume (CBV) and time to peak (TTP) in the hemispheres ipsilateral and contralateral to ICAO. Based on the measurements, the ipsilateral to contralateral ratio for each parameter was calculated and compared. Results: Irrespective of the collateral patterns, ipsilateral CBF was not significantly different from that of the contralateral hemisphere (P = 0.285); ipsilateral CBV and TTP was significantly increased compared with those of the contralateral hemisphere (P = 0.000 and P = 0.000 for CBV and TTP, respectively). Furthermore, patients with secondary collaterals had significantly larger ipsilateral-to-contralateral ratios for both CBV (rCBV, P = 0.0197) and TTP (rTTP, P = 0.000) than those of patients with only primary collaterals. These two groups showed no difference in ipsilateral-to-contralateral ratio for CBF (rCBF, P = 0.312). Conclusion: Patients with symptomatic unilateral ICAO in our study were in an autoregulatory vasodilatation status. Moreover, secondary collaterals in ICAO patients were correlated with ipsilateral CBV and delayed TTP that suggested severe hemodynamic impairment, presumably increasing the risk of ischemic events.

  12. Perfusion patterns of metastatic gastrointestinal stromal tumor lesions under specific molecular therapy

    Energy Technology Data Exchange (ETDEWEB)

    Schlemmer, Marcus [Department of Internal Medicine III, University Hospitals-Grosshadern, Ludwig Maximilians University Munich, Marchioninistr. 15, 81377 Munich (Germany); Sourbron, Steven P. [Institute of Clinical Radiology, University Hospitals-Grosshadern, Ludwig Maximilians University Munich, Marchioninistr. 15, 81377 Munich (Germany); Schinwald, Nicole [Department of Internal Medicine III, University Hospitals-Grosshadern, Ludwig Maximilians University Munich, Marchioninistr. 15, 81377 Munich (Germany); Nikolaou, Konstantin; Becker, Christoph R.; Reiser, Maximilian F. [Institute of Clinical Radiology, University Hospitals-Grosshadern, Ludwig Maximilians University Munich, Marchioninistr. 15, 81377 Munich (Germany); Berger, Frank, E-mail: Frank.Berger@med.uni-muenchen.de [Institute of Clinical Radiology, University Hospitals-Grosshadern, Ludwig Maximilians University Munich, Marchioninistr. 15, 81377 Munich (Germany)

    2011-02-15

    Rationale and objective: The aim of this pilot study was the evaluation of CT perfusion patterns in metastatic GIST lesions under specific molecular therapy with sunitinib or imatinib both in responders and non-responders. Patients and methods: 24 patients with metastatic GIST under tyrosine kinase inhibition were retrospectively evaluated. A total of 46 perfusion and venous phase CT scans were acquired. Volume of distribution, blood flow, blood volume, permeability and hepatic perfusion index measurements of metastatic lesions were carried out. Lesions were classified as 'good response' or 'poor response' to therapy, and perfusion parameters were compared for these two types of lesions. Results: 24 patients were evaluated. In the extrahepatic abdominal lesions (N = 15), good responders showed significant lower perfusion values than poor responders (volume of distribution: 3.3 {+-} 2.0 vs. 13.0 {+-} 1.8 ml/100 ml, p = 0.001). The same tendency was observed in intrahepatic lesions (N = 31) (liver volume of distribution: 2.1 {+-} 0.3 vs. 7.1 {+-} 1.3 ml/100 ml, p = 0.003); (hepatic perfusion index: 24.3 {+-} 7.9 vs. 76.1 {+-} 1.5%, p = 0.0001). Conclusion: Our data indicate that there are characteristic perfusion patterns of metastatic GIST lesions showing a good or poor response to molecular pharmacotherapy. Perfusion should be further evaluated in cross-sectional imaging studies as a possible biomarker for treatment response in targeted therapies of GIST.

  13. Effects of Ginkgo biloba on cerebral blood flow assessed by quantitative MR perfusion imaging: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Mashayekh, Ameneh; Pham, Dzung L.; Yousem, David M.; Dizon, Mercedes; Barker, Peter B.; Lin, Doris D.M. [Johns Hopkins University School of Medicine, Department of Radiology, Division of Neuroradiology, Baltimore, MD (United States)

    2011-03-15

    Extract of Ginkgo biloba (EGb), a dietary supplement used for a number of conditions including dementia, has been suggested to increase cerebral blood flow (CBF). The purpose of this study was to determine if changes in CBF could be detected by dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) in elderly human subjects taking EGb. DSC-MRI was performed in nine healthy men (mean age 61 {+-} 10 years) before and after 4 weeks of 60 mg EGb taken twice daily. One subject underwent six consecutive scans to evaluate intrasubject reproducibility. CBF values were computed before and after EGb, and analyzed at three different levels of spatial resolution, using voxel-based statistical parametric mapping (SPM), and regions of interest in different lobes, and all regions combined. Normalized intrasubject CBF (nCBF) measurements had a standard deviation of 7% and 4% in gray and white matter (WM) regions, respectively. SPM using an uncorrected, voxel-level threshold of P {<=} 0.001 showed a small CBF increase in the left parietal-occipital region. CBF in individual lobar regions did not show any significant change post-EGb, but all regions combined showed a significant increase of non-normalized CBF after EGb (15% in white and 13% in gray matter, respectively, P {<=} 0.0001). nCBF measured by DSC-MRI has good intrasubject reproducibility. In this small cohort of normal elderly individuals, a mild increase in CBF is found in the left parietal-occipital WM after EGb, as well as a small but statistically significant increase in global CBF. (orig.)

  14. 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...

  15. The optimal scheme of self blood pressure measurement as determined from ambulatory blood pressure recordings

    NARCIS (Netherlands)

    Verberk, Willem J.; Kroon, Abraham A.; Kessels, Alfons G. H.; Lenders, Jacques W. M.; Thien, Theo; van Montfrans, Gert A.; Smit, Andries J.; de Leeuw, Peter W.

    Objective To determine how many self-measurements of blood pressure (BP) should be taken at home in order to obtain a reliable estimate of a patient's BP. Design Participants performed self blood pressure measurement (SBPM) for 7 days (triplicate morning and evening readings). In all of them, office

  16. The determination of chromium-50 in human blood and its utilization for blood volume measurements

    International Nuclear Information System (INIS)

    Zeisler, R.; Young, I.

    1986-01-01

    Possible relationships between insufficient blood volume increases during pregnancy and infant mortality could be established with an adequate measurement procedure. An accurate and precise technique for blood volume measurements has been found in the isotope dilution technique using chromium-51 as a label for red blood cells. However, in a study involving pregnant women, only stable isotopes can be used for labeling. Stable chromium-50 can be determined in total blood samples before and after dilution experiments by neutron activation analysis (NAA) or mass spectrometry. However, both techniques may be affected by insufficient sensitivity and contamination problems at the inherently low natural chromium concentrations to be measured in the blood. NAA procedures involving irradiations with highly thermalized neutrons at a fluence rate of 2x10 13 n/cm 2 xs and low background gamma spectrometry are applied to the analysis of total blood. Natural levels of chromium-50 in human and animal blood have been found to be <0.1 ng/mL; i.e., total chromium levels of <3 ng/mL. Based on the NAA procedure, a new approach to the blood volume measurement via chromium-50 isotope dilution has been developed which utilizes the ratio of the induced activities of chromium-51 to the iron-59 in three blood samples taken from each individual, namely blank, labeled and diluted labeled blood. (author)

  17. Quantitative aspects of myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Vogel, R.A.

    1980-01-01

    Myocardial perfusion measurements have traditionally been performed in a quantitative fashion using application of the Sapirstein, Fick, Kety-Schmidt, or compartmental analysis principles. Although global myocardial blood flow measurements have not proven clinically useful, regional determinations have substantially advanced our understanding of and ability to detect myocardial ischemia. With the introduction of thallium-201, such studies have become widely available, although these have generally undergone qualitative evaluation. Using computer-digitized data, several methods for the quantification of myocardial perfusion images have been introduced. These include orthogonal and polar coordinate systems and anatomically oriented region of interest segmentation. Statistical ranges of normal and time-activity analyses have been applied to these data, resulting in objective and reproducible means of data evaluation

  18. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

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

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...

  19. 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%

  20. Automated measurement of retinal blood vessel tortuosity

    Science.gov (United States)

    Joshi, Vinayak; Reinhardt, Joseph M.; Abramoff, Michael D.

    2010-03-01

    Abnormalities in the vascular pattern of the retina are associated with retinal diseases and are also risk factors for systemic diseases, especially cardiovascular diseases. The three-dimensional retinal vascular pattern is mostly formed congenitally, but is then modified over life, in response to aging, vessel wall dystrophies and long term changes in blood flow and pressure. A characteristic of the vascular pattern that is appreciated by clinicians is vascular tortuosity, i.e. how curved or kinked a blood vessel, either vein or artery, appears along its course. We developed a new quantitative metric for vascular tortuosity, based on the vessel's angle of curvature, length of the curved vessel over its chord length (arc to chord ratio), number of curvature sign changes, and combined these into a unidimensional metric, Tortuosity Index (TI). In comparison to other published methods this method can estimate appropriate TI for vessels with constant curvature sign and vessels with equal arc to chord ratios, as well. We applied this method to a dataset of 15 digital fundus images of 8 patients with Facioscapulohumeral muscular dystrophy (FSHD), and to the other publically available dataset of 60 fundus images of normal cases and patients with hypertensive retinopathy, of which the arterial and venous tortuosities have also been graded by masked experts (ophthalmologists). The method produced exactly the same rank-ordered list of vessel tortuosity (TI) values as obtained by averaging the tortuosity grading given by 3 ophthalmologists for FSHD dataset and a list of TI values with high ranking correlation with the ophthalmologist's grading for the other dataset. Our results show that TI has potential to detect and evaluate abnormal retinal vascular structure in early diagnosis and prognosis of retinopathies.

  1. Critical evaluation of blood volume measurements during hemodialysis.

    Science.gov (United States)

    Dasselaar, Judith J; van der Sande, Frank M; Franssen, Casper F M

    2012-01-01

    Devices that continuously measure relative blood volume (RBV) changes during hemodialysis (HD) are increasingly used for the prevention of dialysis hypotension and fine-tuning of dry weight. However, RBV measurements are subject to various limitations. First, RBV devices provide information on relative blood volume changes but not on absolute blood volume. Since blood volume varies with the hydration status, identical reductions of RBV may result in very different absolute blood volumes at the end of HD. Second, RBV changes underestimate the change of total blood volume due to translocation of lower-hematocrit blood from the microcirculation to the central circulation. Third, changes in posture before and during HD, food intake, exercise, and administration of intravenous fluids may influence the validity of the RBV measurement. Fourth, results obtained by various RBV devices show large interdevice differences. Finally, although a fall in blood volume is an important factor in dialysis hypotension, frank dialysis hypotension only occurs when the cardiovascular compensatory mechanisms can no longer compensate for the reduction in blood volume. Therefore, the dialysis staff should not exclusively focus on RBV, but also search for opportunities in the dialysis prescription to facilitate cardiovascular compensatory mechanisms, e.g. by lowering dialysate temperature. In the opinion of the authors, routine RBV monitoring should be used with caution until the major conceptual and methodological problems that are inherent to the indirect RBV estimation are clarified. Copyright © 2012 S. Karger AG, Basel.

  2. TREATMENT OF HYPERTENSION USING TELEMEDICAL HOME BLOOD PRESSURE MEASUREMENTS

    DEFF Research Database (Denmark)

    Hoffmann-Petersen, N; Lauritzen, T; Bech, J N

    2015-01-01

    OBJECTIVE: Telemonitoring of home blood pressure measurements (TBPM) is a new and promising supplement to diagnosis, control and treatment of hypertension. We wanted to compare the outcome of antihypertensive treatment based on TBPM and conventional monitoring of blood pressure. DESIGN AND METHOD...... of the measurements and subsequent communication by telephone or E-mail. In the control group, patients received usual care. Primary outcome was reduction in daytime ambulatory blood pressure measurements (ABPM) from baseline to 3 months' follow-up. RESULTS: In both groups, daytime ABPM decreased significantly....../181), p = 0.34. Blood pressure reduction in the TBPM group varied with the different practices. CONCLUSIONS: No further reduction in ABPM or number of patients reaching blood pressure targets was observed when electronic transmission of TBPM was applied in the treatment of hypertension by GPs. Thus...

  3. Correlation between nuclear perfusion parameters and duplex US indices in the diagnosis of renal allograft rejection

    International Nuclear Information System (INIS)

    Kim, E.E.; Maklad, N.F.; Pjura, G.A.; Lowry, P.A.

    1986-01-01

    Fifty nuclear perfusion and duplex US studies in 30 patients who had received renal allografts were prospectively analyzed to evaluate their respective measures of blood flow as indicators of rejection. The nuclear study (Tc-99m DTPA) generated three parameters, and a real-time, pulsed Doppler sector scanner generated resistance and pulsatility indices. In nine cases with a greater than 70% resistance index and 1.4 pulsatility index on US, the US findings correlated well with changes in nuclear perfusion parameters, indication rejection. The authors conclude that the combination of decreasing nuclear perfusion parameters and positive US indices may obviate the need for biopsy in the diagnosis of allograft rejection

  4. CT perfusion imaging of the liver and the spleen in patients with cirrhosis: Is there a correlation between perfusion and portal venous hypertension?

    Energy Technology Data Exchange (ETDEWEB)

    Talakic, Emina; Schoellnast, Helmut [Medical University of Graz, Division of General Radiology, Department of Radiology, Graz (Austria); Schaffellner, Silvia; Kniepeiss, Daniela; Mueller, Helmut [Medical University of Graz, Department of Surgery, Division of Transplantation Surgery, Graz (Austria); Stauber, Rudolf [Medical University of Graz, Department of Internal Medicine, Division of Gastoenterology and Hepatology, Graz (Austria); Quehenberger, Franz [Medical University of Graz, Institute for Medical Informatics, Statistics and Documentation, Graz (Austria)

    2017-10-15

    To correlate hepatic and splenic CT perfusion parameters with hepatic venous pressure gradient (HVPG) measurements in patients with cirrhosis. Twenty-one patients with cirrhosis (males, 17; females, 4; mean ± SD age, 57 ± 7 years) underwent hepatic and splenic perfusion CT on a 320-detector row volume scanner as well as invasive measurement of HVPG. Different CT perfusion algorithms (maximum slope analysis and Patlak plot) were used to measure hepatic arterial flow (HAF), portal venous flow (PVF), hepatic perfusion index (HPI), splenic arterial flow (SAF), splenic blood volume (SBV) and splenic clearance (SCL). Hepatic and splenic perfusion parameters were correlated with HVPG, and sensitivity and specificity for detection of severe portal hypertension (≥12 mmHg) were calculated. The Spearman correlation coefficient was -0.53 (p < 0.05) between SAF and HVPG, and -0.68 (p < 0.01) between HVPG and SCL. Using a cut-off value of 125 ml/min/100 ml for SCL, sensitivity for detection of a HVPG of ≥12 mmHg was 94%, and specificity 100%. There was no significant correlation between hepatic perfusion parameters and HVPG. CT perfusion in patients with cirrhosis showed a strong correlation between SCL and HVPG and may be used for detection of severe portal hypertension. (orig.)

  5. CT perfusion imaging of the liver and the spleen in patients with cirrhosis: Is there a correlation between perfusion and portal venous hypertension?

    Science.gov (United States)

    Talakić, Emina; Schaffellner, Silvia; Kniepeiss, Daniela; Mueller, Helmut; Stauber, Rudolf; Quehenberger, Franz; Schoellnast, Helmut

    2017-10-01

    To correlate hepatic and splenic CT perfusion parameters with hepatic venous pressure gradient (HVPG) measurements in patients with cirrhosis. Twenty-one patients with cirrhosis (males, 17; females, 4; mean ± SD age, 57 ± 7 years) underwent hepatic and splenic perfusion CT on a 320-detector row volume scanner as well as invasive measurement of HVPG. Different CT perfusion algorithms (maximum slope analysis and Patlak plot) were used to measure hepatic arterial flow (HAF), portal venous flow (PVF), hepatic perfusion index (HPI), splenic arterial flow (SAF), splenic blood volume (SBV) and splenic clearance (SCL). Hepatic and splenic perfusion parameters were correlated with HVPG, and sensitivity and specificity for detection of severe portal hypertension (≥12 mmHg) were calculated. The Spearman correlation coefficient was -0.53 (p perfusion parameters and HVPG. CT perfusion in patients with cirrhosis showed a strong correlation between SCL and HVPG and may be used for detection of severe portal hypertension. • SAF and SCL are statistically significantly correlated with HVPG • SCL showed stronger correlation with HVPG than SAF • 125 ml/min/100 ml SCL-cut-off yielded 94 % sensitivity, 100 % specificity for severe PH • HAF, PVF and HPI showed no statistically significant correlation with HVPG.

  6. Cutaneous oxygen uptake and its relation to skin blood perfusion and ambient salinity in the plaice, Pleuronectes platessa

    DEFF Research Database (Denmark)

    Steffensen, J F; Lomholt, J P

    1985-01-01

    Oxygen uptake across plaice skin was unaffected by temporary arrest of skin blood flow. This indicates that oxygen taken up across the skin is consumed by the skin itself. Weight specific rate of O2-consumption of skin is estimated to be 1.7-1.9 times that of the entire fish. Total resting O2...

  7. Self-monitoring of blood glucose measurements and glycaemic ...

    African Journals Online (AJOL)

    Background. Intensive diabetes management requires intensive insulin treatment and self-monitoring of blood glucose (SMBG) measurements to obtain immediate information on the status of the blood glucose level and to obtain data for pattern analysis on which meal planning, insulin and lifestyle adjustments can be ...

  8. Association between blood pressure, measures of body composition ...

    African Journals Online (AJOL)

    Risk factors for development of cardiovascular disease develop early in life and track into adulthood. This study investigated the relationship between blood pressure (BP) and measures of body composition in adolescents. The study participants were 307 adolescents. Blood pressure (BP) and anthropometric parameters: ...

  9. Perioperative blood saving measures in total hip and knee arthroplasty

    NARCIS (Netherlands)

    Horstmann, W.G.

    2011-01-01

    This dissertation explores and discusses different aspects of blood loss and blood-saving measures in total hip and knee arthroplasty. Background: Worldwide, approximately 1 million total hip and 1 million total knee prostheses are implanted each year. Total hip arthroplasty and total

  10. 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

  11. Oscillometric blood pressure measurements: differences between measured and calculated mean arterial pressure.

    NARCIS (Netherlands)

    Kiers, H.D.; Hofstra, J.M.; Wetzels, J.F.M.

    2008-01-01

    Mean arterial pressure (MAP) is often used as an index of overall blood pressure. In recent years, the use of automated oscillometric blood pressure measurement devices is increasing. These devices directly measure and display MAP; however, MAP is often calculated from systolic blood pressure (SBP)

  12. A Review of Liver Perfusion Method in Toxicology Studies

    Directory of Open Access Journals (Sweden)

    M karami

    2014-06-01

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

  13. Home blood pressure measurement in elderly patients with cognitive impairment: comparison of agreement between relative-measured blood pressure and automated blood pressure measurement.

    Science.gov (United States)

    Plichart, Matthieu; Seux, Marie-Laure; Caillard, Laure; Chaussade, Edouard; Vidal, Jean-Sébastien; Boully, Clémence; Hanon, Olivier

    2013-08-01

    Home blood pressure measurement (HBPM) is recommended by guidelines for hypertension management. However, this method might be difficult to use in elderly individuals with cognitive disorders. Our aim was to assess the agreement and the feasibility of HBPM by a relative as compared with 24-h ambulatory blood pressure monitoring (ABPM) in elderly patients with dementia. Sixty outpatients with dementia aged 75 years and older with office hypertension (≥140/90 mmHg) were subjected successively to HBPM by a trained relative and 24-h ABPM. The order of the two methods was randomized. Current guidelines' thresholds for the diagnosis of hypertension were used. The mean (SD) age of the patients was 80.8 (6.1) years (55% women) and the mean (SD) mini-mental state examination score was 20.1 (6.9). The feasibility of relative-HBPM was very high, with a 97% success rate (defined by ≥12/18 measurements reported). The blood pressure measurements were highly correlated between the two methods (r=0.75 and 0.64 for systolic blood pressure and diastolic blood pressure, respectively; Pmethods for the diagnosis of sustained hypertension and white-coat hypertension was excellent (overall agreement, 92%; κ coefficient, 0.81; 95% CI, 0.61-0.93). Similar results were found for daytime-ABPM. In cognitively impaired elderly patients, HBPM by a relative using an automated device was a good alternative to 24-h ABPM.

  14. 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...

  15. Establishment of normal limits for left ventricular ejection fraction and volume measurements from 99Tcm-sestamibi myocardial perfusion gated SPECT

    International Nuclear Information System (INIS)

    Zhang Wanchun; Li Sijin; Kang Chunsong; Hu Guang; Liu Jianzhong; Wang Jin; Kong Fanzhen

    2004-01-01

    Objective: Gated SPECT is a reproducible method for assessing left ventricular volume (LVV) and left ventricular ejection fraction (LVEF) from 99 Tcm-sestamibi ( 99 Tcm-MIBI) myocardial perfusion imaging studies. LVV and LVEF measurements by this approach correlate well with those obtained from other cardiovascular imaging techniques. Nevertheless, the lack of criteria for abnormal test findings has limited the potential clinical application of this new imaging technique. Methods: Gated myocardial perfusion SPECT with 99 Tcm-MIBI (QGSPECT) was performed on 96 individuals with a low Bayesian likelihood ( 99 Tcm-MIBI, 2-dimensional echocardiography was performed on 30 cases within 72 h. Results: The correlation between rest QGSPECT and 2-dimensional echocardiography was r=0.714 for LVEF (p 2 in men and ≤60 ml/m 2 in women, and ESV index ≤41 ml/m 2 in men and ≤25 ml/m 2 in women. Conclusion: (1) Quantification of LV function can be accurately evaluated using gated myocardial perfusion SPECT with 99 Tcm-MIBI, (2) Using a cohort of low-likelihood subjects, we generated sex-specific normal limits for LVV and LVEF for myocardial perfusion gated SPECT. These normal limits can now be evaluated prospectively for their potential clinical value. (authors)

  16. A quantitative high resolution voxel-wise assessment of myocardial blood flow from contrast-enhanced first-pass magnetic resonance perfusion imaging: microsphere validation in a magnetic resonance compatible free beating explanted pig heart model.

    Science.gov (United States)

    Schuster, Andreas; Sinclair, Matthew; Zarinabad, Niloufar; Ishida, Masaki; van den Wijngaard, Jeroen P H M; Paul, Matthias; van Horssen, Pepijn; Hussain, Shazia T; Perera, Divaka; Schaeffter, Tobias; Spaan, Jos A E; Siebes, Maria; Nagel, Eike; Chiribiri, Amedeo

    2015-10-01

    To assess the feasibility of high-resolution quantitative cardiovascular magnetic resonance (CMR) voxel-wise perfusion imaging using clinical 1.5 and 3 T sequences and to validate it using fluorescently labelled microspheres in combination with a state of the art imaging cryomicrotome in a novel, isolated blood-perfused MR-compatible free beating pig heart model without respiratory motion. MR perfusion imaging was performed in pig hearts at 1.5 (n = 4) and 3 T (n = 4). Images were acquired at physiological flow ('rest'), reduced flow ('ischaemia'), and during adenosine-induced hyperaemia ('stress') in control and coronary occlusion conditions. Fluorescently labelled microspheres and known coronary myocardial blood flow represented the reference standards for quantitative perfusion validation. For the comparison with microspheres, the LV was divided into 48 segments based on a subdivision of the 16 AHA segments into subendocardial, midmyocardial, and subepicardial subsegments. Perfusion quantification of the time-signal intensity curves was performed using a Fermi function deconvolution. High-resolution quantitative voxel-wise perfusion assessment was able to distinguish between occluded and remote myocardium (P < 0.001) and between rest, ischaemia, and stress perfusion conditions at 1.5 T (P < 0.001) and at 3 T (P < 0.001). CMR-MBF estimates correlated well with the microspheres at the AHA segmental level at 1.5 T (r = 0.94, P < 0.001) and at 3 T (r = 0.96, P < 0.001) and at the subendocardial, midmyocardial, and subepicardial level at 1.5 T (r = 0.93, r = 0.9, r = 0.88, P < 0.001, respectively) and at 3 T (r = 0.91, r = 0.95, r = 0.84, P < 0.001, respectively). CMR-derived voxel-wise quantitative blood flow assessment is feasible and very accurate compared with microspheres. This technique is suitable for both clinically used field strengths and may provide the tools to assess extent and severity of myocardial ischaemia. Published on behalf of the European Society

  17. Clinical application of cerebral dynamic perfusion studies

    International Nuclear Information System (INIS)

    DeLand, F.H.

    1975-01-01

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

  18. Relative Flow Reserve Derived From Quantitative Perfusion Imaging May Not Outperform Stress Myocardial Blood Flow for Identification of Hemodynamically Significant Coronary Artery Disease

    NARCIS (Netherlands)

    Stuijfzand, W.J.A.; Uusitalo, V.; Kero, T.; Danad, I.; Rijnierse, M.T.; Saraste, A.; Raijmakers, P.G.; Lammertsma, A.A.; Harms, H.J.; Heymans, M.W.; Huisman, M.C.; Marques, K.M.; Kajander, S.A.; Pietila, M.; Sorensen, J.; van Royen, N.; Knuuti, J.; Knaapen, P.

    2015-01-01

    Background: Quantitative myocardial perfusion imaging is increasingly used for the diagnosis of coronary artery disease. Quantitative perfusion imaging allows to noninvasively calculate fractional flow reserve (FFR). This so-called relative flow reserve (RFR) is defined as the ratio of hyperemic

  19. Blood pressure measurements in the ankle are not equivalent to ...

    African Journals Online (AJOL)

    Background. Blood pressure (BP) is often measured on the ankle in the emergency department (ED), but this has never been shown to be an acceptable alternative to measurements performed on the arm. Objective. To establish whether the differences between arm and ankle non-invasive BP measurements were clinically ...

  20. Epidermal Inorganic Optoelectronics for Blood Oxygen Measurement.

    Science.gov (United States)

    Li, Haicheng; Xu, Yun; Li, Xiaomin; Chen, Ying; Jiang, Yu; Zhang, Changxing; Lu, Bingwei; Wang, Jian; Ma, Yinji; Chen, Yihao; Huang, Yin; Ding, Minquang; Su, Honghong; Song, Guofeng; Luo, Yi; Feng, X

    2017-05-01

    Flexible and stretchable optoelectronics, built-in inorganic semiconductor materials, offer a wide range of unprecedented opportunities and will redefine the conventional rigid optoelectronics in biological application and medical measurement. However, a significant bottleneck lies in the brittleness nature of rigid semiconductor materials and the performance's extreme sensitivity to the light intensity variation due to human skin deformation while measuring physical parameters. In this study, the authors demonstrate a systematic strategy to design an epidermal inorganic optoelectronic device by using specific strain-isolation design, nanodiamond thinning, and hybrid transfer printing. The authors propose all-in-one suspension structure to achieve the stretchability and conformability for surrounding environment, and they propose a two-step transfer printing method for hybrid integrating III-V group emitting elements, Si-based photodetector, and interconnects. Owing to the excellent flexibility and stretchability, such device is totally conformal to skin and keeps the constant light transmission between emitting element and photodetector as well as the signal stability due to skin deformation. This method opens a route for traditional inorganic optoelectronics to achieve flexibility and stretchability and improve the performance of optoelectronics for biomedical application. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Quantitative hepatic CT perfusion measurement: Comparison of Couinaud's hepatic segments with dual-source 128-slice CT

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuan [The Department of Radiology, Peking Union Medical College Hospital, Dongcheng District, Beijing, 100730 (China); Xue, Hua-dan, E-mail: bjdanna95@hotmail.com [The Department of Radiology, Peking Union Medical College Hospital, Dongcheng District, Beijing, 100730 (China); Jin, Zheng-yu, E-mail: jin_zhengyu@163.com [The Department of Radiology, Peking Union Medical College Hospital, Dongcheng District, Beijing, 100730 (China); Su, Bai-yan; Li, Zhuo; Sun, Hao; Chen, Yu; Liu, Wei [The Department of Radiology, Peking Union Medical College Hospital, Dongcheng District, Beijing, 100730 (China)

    2013-02-15

    Purpose: To compare the quantitative liver computed tomography perfusion (CTP) differences among eight hepatic segments. Materials and methods: This retrospective study was based on 72 acquired upper abdomen CTP scans for detecting suspected pancreas tumor. Patients with primary or metastatic liver tumor, any focal liver lesions except simple cyst (<3 cm in diameter), history of liver operation or splenectomy, evidence of liver cirrhosis or invasion of portal vein were excluded. The final analysis included 50 patients (M:F = 21:29, mean age = 43.2 years, 15–76 years). Arterial liver perfusion (ALP), portal-venous perfusion (PVP), total hepatic perfusion (THP = ALP + PVP), and hepatic perfusion index (HPI) of each hepatic segment were calculated and compared by means of one-way analysis of variance (ANOVA) and the Bonferonni correction method. Results: Compared to hepatic segments 5, 6, 7 and 8, segments 2 and 3 showed a tendency of higher ALPs, lower PVPs, and higher HPIs, most of which were statistically significant (p < 0.05). Hepatic segments 1 and 4 had higher mean values of ALP and HPI and lower mean values of PVP than segments 5, 6, 7 and 8 as well, although no significant differences were detected except for ALP and HPI for liver segments 1 and 7 (p = 0.001 and 0.035 respectively), and ALP for liver segments 1 and 5 (p = 0.039). Higher ALP and HPI were showed in hepatic segment 3 compared to segment 4 (p = 0.000 and 0.000 respectively). No significant differences were found for THP among eight segments. Conclusions: Intra-hepatic perfusion differences exist in normal hepatic parenchyma especially between lateral sector (segments 2 and 3) and right lobe (segments 5, 6, 7 and 8). This might have potential clinical significance in liver-perfusion-related protocol design and result analysis.

  2. 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.

  3. Comparison of ambulatory blood pressure monitoring and office blood pressure measurements in obese children and adolescents.

    Science.gov (United States)

    Renda, Rahime

    2018-04-01

    Obesity in adults has been related to hypertension and abnormal nocturnal dipping of blood pressure, which are associated with poor cardiovascular and renal outcomes. Here, we aimed to resolve the relationship between the degree of obesity, the severity of hypertension and dipping status on ambulatory blood pressure in obese children. A total 72 patients with primary obesity aged 7 to 18 years (mean: 13.48 ± 3.25) were selected. Patients were divided into three groups based on body mass index (BMİ) Z-score. Diagnosis and staging of ambulatory hypertension based on 24-h blood pressure measurements, obtained from ambulatory blood pressure monitoring. Based on our ambulatory blood pressure data, 35 patients (48.6%) had hypertension, 7 (20%) had ambulatory prehypertension, 21 (60%) had hypertension, and 7 patients (20%) had severe ambulatory hypertension. There was a significant relationship between severity of hypertension and the degree of obesity (p lood pressure results and loads were similar between groups. Diastolic and mean arterial blood pressure levels during the night, diastolic blood pressure loads, and heart rate during the day were significantly higher in Group 3 (p lood pressure at night, mean arterial pressure at night, diastolic blood pressure loads and heart rate at day. Increase in BMI Z-score does not a significant impact on daytime blood pressure and nocturnal dipping status.

  4. Perfusion CT in acute stroke

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  5. The diagnosis of deep venous thrombosis using laser Doppler skin perfusion measurements

    NARCIS (Netherlands)

    de Graaff, J. C.; Ubbink, D. T.; Büller, H. R.; Jacobs, M. J.

    2001-01-01

    Compression ultrasonography (CUS) falls short in the diagnosis of deep venous thrombosis in asymptomatic patients and thrombi limited to the calf veins. Alternatively, laser Doppler fluxmetry (LDF) may be useful for this purpose, as it can measure the peripheral vasoconstriction response upon an

  6. Measurement and Comparison of Organic Compound Concentrations in Plasma, Whole Blood and Dried Blood Spot Samples

    Directory of Open Access Journals (Sweden)

    Stuart A Batterman

    2016-04-01

    Full Text Available The preferred sampling medium for measuring human exposures of persistent organic compounds (POPs is blood, and relevant sample types include whole blood, plasma, and dried blood spots (DBS. Because information regarding the performance and comparability of measurements across these sample types is limited, it is difficult to compare across studies. This study evaluates the performance of POP measurements in plasma, whole blood and DBS, and presents the distribution coefficients needed to convert concentrations among the three sample types. Blood samples were collected from adult volunteers, along with demographic and smoking information, and analyzed by GC/MS for organochlorine pesticides (OCPs, chlorinated hydrocarbons (CHCs, polychlorinated biphenyls (PCBs, and brominated diphenyl ethers (PBDEs. Regression models were used to evaluate the relationships between the sample types and possible effects of personal covariates. Distribution coefficients also were calculated using physically-based models.Across all compounds, concentrations in plasma were consistently the highest; concentrations in whole blood and DBS samples were comparable. Distribution coefficients for plasma to whole blood concentrations ranged from 1.74 to 2.26 for pesticides/CHCs, averaged 1.69 ± 0.06 for the PCBs, and averaged 1.65 ± 0.03 for the PBDEs. Regression models closely fit most chemicals (R2 > 0.80, and whole blood and DBS samples generally showed very good agreement. Distribution coefficients estimated using biologically-based models were near one and did not explain the observed distribution. Among the study population, median concentrations of several pesticides/CHCs and PBDEs exceeded levels reported in the 2007-2008 National Health and Nutrition Examination Survey, while levels of other OCPs and PBDEs were comparable or lower. Race and smoking status appeared to slightly affect plasma/blood concentration ratios for several POPs. The experimentally

  7. Utilizing flat-panel detector parenchymal blood volume imaging (FD-PBV) for quantitative kidney perfusion analysis during the process of percutaneous transluminal renal angioplasty (PTRA): A case report.

    Science.gov (United States)

    Qiu, Chenyang; Shao, Jiang; Liu, Xiu; Liu, Bao

    2017-11-01

    Traditional digital subtraction angiography (DSA) provides lumen morphology of renal artery as indicators for vascular patency in patients with renal artery stenosis (RAS). It, however, lacks hemodynamic information toward target kidney. To solve this shortcoming, a novel technique, flat-panel detector parenchymal blood volume imaging (FD-PBV), is introduced, which is able to evaluate hemodynamic changes of target kidney intraoperatively. A 77-year-old female presented with hypertension, intermittent dizziness, nausea, and fatigue. Ninety-nine percent stenosis of left RAS was found. Percutaneous transluminal renal angioplasty was performed, along with FD-PBV acquisition protocol. Her symptoms relieved gradually after procedure. Intuitive FD-PBV maps showed her renal perfusion improved remarkably. Quantitative analysis of FD-PBV showed her kidney volume was 47.02 and 75.61 cm with average density of contrast medium (CM) 58.1 HU and 311.5 HU before and after stenting. Follow-up at 6 months showed patency of the stent and stable kidney blood perfusion. FD-PBV technique possesses a remarkable value in quantitatively assessing the changes of kidney blood perfusion and can be a useful auxiliary technique for DSA. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

  8. 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....

  9. 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.

  10. CORRELATION OF OCULAR PERFUSION PRESSURE AND INTRAOCULAR PRESSURE CHANGES DURING HAEMODIALYSIS IN END STAGE RENAL DISEASE- AN OBSERVATIONAL STUDY

    Directory of Open Access Journals (Sweden)

    T. R. Anuradha

    2017-12-01

    Full Text Available BACKGROUND Chronic kidney disease patients on haemodialysis have a transient raise in intraocular pressure and decrease in ocular perfusion pressure. This is used in early detection of glaucomatous optic nerve damage and subsequent irreversible visual loss. MATERIALS AND METHODS 100 chronic kidney disease patients under haemodialysis in the nephrology department, Stanley medical college for more than one month were included in the study. We recorded complete history, and all participants were subjected to Intraocular pressure and blood pressure measurement at 3 different timings during haemodialysis session. Mean Arterial Pressure (MAP, Ocular Perfusion Pressure (OPP, Systolic Ocular Perfusion Pressure (SOPP, Diastolic Ocular Perfusion Pressure (DOPP and Mean Ocular Perfusion Pressure (MOPP were calculated. RESULTS Mean IOP from the initiation to the end of haemodialysis was found to be increased. Mean arterial pressure, ocular perfusion pressure, systolic ocular perfusion pressure, diastolic ocular perfusion pressure, mean ocular perfusion pressure was found to be decreased from the initiation to the end of haemodialysis. At the end of study period, 10% were found to develop early glaucomatous field defects and early optic nerve head changes in both eyes at follow-up. CONCLUSION Our study reveals the importance of screening and monitoring of intraocular pressure and characteristic early optic nerve head changes and early visual field changes of glaucoma in end-stage renal disease patients who are on haemodialysis.

  11. Estimating myocardial perfusion from dynamic contrast-enhanced CMR with a model-independent deconvolution method

    Directory of Open Access Journals (Sweden)

    Kadrmas Dan J

    2008-11-01

    Full Text Available Abstract Background Model-independent analysis with B-spline regularization has been used to quantify myocardial blood flow (perfusion in dynamic contrast-enhanced cardiovascular magnetic resonance (CMR studies. However, the model-independent approach has not been extensively evaluated to determine how the contrast-to-noise ratio between blood and tissue enhancement affects estimates of myocardial perfusion and the degree to which the regularization is dependent on the noise in the measured enhancement data. We investigated these questions with a model-independent analysis method that uses iterative minimization and a temporal smoothness regularizer. Perfusion estimates using this method were compared to results from dynamic 13N-ammonia PET. Results An iterative model-independent analysis method was developed and tested to estimate regional and pixelwise myocardial perfusion in five normal subjects imaged with a saturation recovery turboFLASH sequence at 3 T CMR. Estimates of myocardial perfusion using model-independent analysis are dependent on the choice of the regularization weight parameter, which increases nonlinearly to handle large decreases in the contrast-to-noise ratio of the measured tissue enhancement data. Quantitative perfusion estimates in five subjects imaged with 3 T CMR were 1.1 ± 0.8 ml/min/g at rest and 3.1 ± 1.7 ml/min/g at adenosine stress. The perfusion estimates correlated with dynamic 13N-ammonia PET (y = 0.90x + 0.24, r = 0.85 and were similar to results from other validated CMR studies. Conclusion This work shows that a model-independent analysis method that uses iterative minimization and temporal regularization can be used to quantify myocardial perfusion with dynamic contrast-enhanced perfusion CMR. Results from this method are robust to choices in the regularization weight parameter over relatively large ranges in the contrast-to-noise ratio of the tissue enhancement data.

  12. Blood pressure self-measurement in the obstetric waiting room

    DEFF Research Database (Denmark)

    Wagner, Stefan; Kamper, Christina H.; Toftegaard, Thomas Skjødeberg

    2013-01-01

    Background: Pregnant diabetic patients are often required to self- measure their blood pressure in the waiting room before consulta- tion. Currently used blood pressure devices do not guarantee valid measurements when used unsupervised. This could lead to misdi- agnosis and treatment error. The aim...... of this study was to investigate current use of blood pressure self-measurement in the waiting room in order to identify challenges that could influence the resulting data quality. Also, we wanted to investigate the potential for addressing these challenges with e-health and telemedicine technology. Subjects...... and Methods: We observed 81 pregnant diabetics’ ability to correctly self-measure in the waiting room during a 4-week observational descriptive study. Specifically, we investigated the level of patient adherence to six recommendations with which patients are in- structed to comply in order to obtain...

  13. Estimating the measurement uncertainty in forensic blood alcohol analysis.

    Science.gov (United States)

    Gullberg, Rod G

    2012-04-01

    For many reasons, forensic toxicologists are being asked to determine and report their measurement uncertainty in blood alcohol analysis. While understood conceptually, the elements and computations involved in determining measurement uncertainty are generally foreign to most forensic toxicologists. Several established and well-documented methods are available to determine and report the uncertainty in blood alcohol measurement. A straightforward bottom-up approach is presented that includes: (1) specifying the measurand, (2) identifying the major components of uncertainty, (3) quantifying the components, (4) statistically combining the components and (5) reporting the results. A hypothetical example is presented that employs reasonable estimates for forensic blood alcohol analysis assuming headspace gas chromatography. These computations are easily employed in spreadsheet programs as well. Determining and reporting measurement uncertainty is an important element in establishing fitness-for-purpose. Indeed, the demand for such computations and information from the forensic toxicologist will continue to increase.

  14. Automatic noninvasive measurement of systolic blood pressure using photoplethysmography

    Directory of Open Access Journals (Sweden)

    Glik Zehava

    2009-10-01

    Full Text Available Abstract Background Automatic measurement of arterial blood pressure is important, but the available commercial automatic blood pressure meters, mostly based on oscillometry, are of low accuracy. Methods In this study, we present a cuff-based technique for automatic measurement of systolic blood pressure, based on photoplethysmographic signals measured simultaneously in fingers of both hands. After inflating the pressure cuff to a level above systolic blood pressure in a relatively slow rate, it is slowly deflated. The cuff pressure for which the photoplethysmographic signal reappeared during the deflation of the pressure-cuff was taken as the systolic blood pressure. The algorithm for the detection of the photoplethysmographic signal involves: (1 determination of the time-segments in which the photoplethysmographic signal distal to the cuff is expected to appear, utilizing the photoplethysmographic signal in the free hand, and (2 discrimination between random fluctuations and photoplethysmographic pattern. The detected pulses in the time-segments were identified as photoplethysmographic pulses if they met two criteria, based on the pulse waveform and on the correlation between the signal in each segment and the signal in the two neighboring segments. Results Comparison of the photoplethysmographic-based automatic technique to sphygmomanometry, the reference standard, shows that the standard deviation of their differences was 3.7 mmHg. For subjects with systolic blood pressure above 130 mmHg the standard deviation was even lower, 2.9 mmHg. These values are much lower than the 8 mmHg value imposed by AAMI standard for automatic blood pressure meters. Conclusion The photoplethysmographic-based technique for automatic measurement of systolic blood pressure, and the algorithm which was presented in this study, seems to be accurate.

  15. Automatic noninvasive measurement of systolic blood pressure using photoplethysmography.

    Science.gov (United States)

    Nitzan, Meir; Patron, Amikam; Glik, Zehava; Weiss, Abraham T

    2009-10-26

    Automatic measurement of arterial blood pressure is important, but the available commercial automatic blood pressure meters, mostly based on oscillometry, are of low accuracy. In this study, we present a cuff-based technique for automatic measurement of systolic blood pressure, based on photoplethysmographic signals measured simultaneously in fingers of both hands. After inflating the pressure cuff to a level above systolic blood pressure in a relatively slow rate, it is slowly deflated. The cuff pressure for which the photoplethysmographic signal reappeared during the deflation of the pressure-cuff was taken as the systolic blood pressure. The algorithm for the detection of the photoplethysmographic signal involves: (1) determination of the time-segments in which the photoplethysmographic signal distal to the cuff is expected to appear, utilizing the photoplethysmographic signal in the free hand, and (2) discrimination between random fluctuations and photoplethysmographic pattern. The detected pulses in the time-segments were identified as photoplethysmographic pulses if they met two criteria, based on the pulse waveform and on the correlation between the signal in each segment and the signal in the two neighboring segments. Comparison of the photoplethysmographic-based automatic technique to sphygmomanometry, the reference standard, shows that the standard deviation of their differences was 3.7 mmHg. For subjects with systolic blood pressure above 130 mmHg the standard deviation was even lower, 2.9 mmHg. These values are much lower than the 8 mmHg value imposed by AAMI standard for automatic blood pressure meters. The photoplethysmographic-based technique for automatic measurement of systolic blood pressure, and the algorithm which was presented in this study, seems to be accurate.

  16. Critical Evaluation of Blood Volume Measurements during Hemodialysis

    NARCIS (Netherlands)

    Dasselaar, Judith J.; van der Sande, Frank M.; Franssen, Casper F. M.

    2012-01-01

    Devices that continuously measure relative blood volume (RBV) changes during hemodialysis (HD) are increasingly used for the prevention of dialysis hypotension and fine-tuning of dry weight. However, RBV measurements are subject to various limitations. First, RBV devices provide information on

  17. assessment of measures of adiposity that correlate with blood ...

    African Journals Online (AJOL)

    Comparing BMI with dual energy xray absorptiometry. (DXA), an example of direct measurement of total .... (HEM711DLX) blood pressure apparatus on the left arm placed at heart level after 5-minute rest and using ... weight, waist and arm circumferences were obtained. Height was measured without shoes to the nearest.

  18. Assessment of measures of adiposity that correlate with blood ...

    African Journals Online (AJOL)

    Background: Studies differ on which anthropometric measure of adiposity shows good correlation with cardiovascular diseases. In this study, we evaluated the effects of common epidemiological measures of adiposity as a correlate of elevated blood pressure in an African population. Methodology: The study was carried out ...

  19. Invasive v. non-invasive blood pressure measurements the ...

    African Journals Online (AJOL)

    A reasonable correlation exists between invasive and noninvasive methods of measuring systemic blood pressure. However, there are frequent individual differences between these methods and these variations have often caused the validity of the non-invasive measurement to be questioned. The hypothesis that certain ...

  20. 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)

  1. Automatic Detection of Myocardial Boundaries in MR Cardio Perfusion Images

    NARCIS (Netherlands)

    Spreeuwers, Luuk; Breeuwer, Marcel

    2001-01-01

    Cardiovascular diseases often result in reduced blood perfusion of the myocardium (MC). Recent advances in MR allow fast recordingof contrast enhanced myocardial perfusion scans. For perfusion analysis the myocardial boundaries must be traced. Currently this is done manually. In this paper a method

  2. Perivenous support reduces early changes in human vein grafts : Studies in whole blood perfused human vein segments

    NARCIS (Netherlands)

    Stooker, W; Niessen, HWM; Baidoshvili, A; Wildevuur, WR; Van Hinsbergh, VWH; Fritz, J; Wildevuur, CRH; Eijsman, L

    Background: Patency of vein grafts in coronary artery bypass grafting procedures is generally less favorable than those of selected arterial grafts. However, vein grafts still are needed in cardiac operations. It would be desirable to find measures to improve the patency of vein grafts next to

  3. Blood-Brain Barrier Permeability Assessed by Perfusion CT Predicts Symptomatic Hemorrhagic Transformation and Malignant Edema in Acute Ischemic Stroke

    NARCIS (Netherlands)

    Hom, J.; Dankbaar, J. W.; Soares, B. P.; Schneider, T.; Cheng, S. -C.; Bredno, J.; Lau, B. C.; Smith, W.; Dillon, W. P.; Wintermark, M.

    BACKGROUND AND PURPOSE: SHT and ME are feared complications in patients with acute ischemic stroke. They occur >10 times more frequently in tPA-treated versus placebo-treated patients. Our goal was to evaluate the sensitivity and specificity of admission BBBP measurements derived from PCT in

  4. Feasibility of ASL spinal bone marrow perfusion imaging with optimized inversion time.

    Science.gov (United States)

    Xing, Dong; Zha, Yunfei; Yan, Liyong; Wang, Kejun; Gong, Wei; Lin, Hui

    2015-11-01

    To assess the correlation between flow-sensitive alternating inversion recovery (FAIR) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in the measurement of spinal bone marrow (SBM) perfusion; in addition, to assess for an optimized inversion time (TI) as well as the reproducibility of SBM FAIR perfusion. The optimized TI of a FAIR SBM perfusion experiment was carried out on 14 volunteers; two adjacent vertebral bodies were selected from each volunteer to measure the change of signal intensity (ΔM) and the signal-to-noise ratio (SNR) of FAIR perfusion MRI with five different TIs. Then, reproducibility of FAIR data from 10 volunteers was assessed by the reposition SBM FAIR experiments. Finally, FAIR and DCE-MRI were performed on 27 subjects. The correlation between the blood flow on FAIR (BFASL ) and perfusion-related parameters on DCE-MRI was evaluated. The maximum value of ΔM and SNR were 36.39 ± 12.53 and 2.38 ± 0.97, respectively; both were obtained when TI was near 1200 msec. There were no significant difference between the two successive measurements of SBM BFASL perfusion (P = 0.879), and the within-subject coefficients of variation (wCV) of the measurements was 3.28%. The BFASL showed a close correlation with K(trans) (P FAIR perfusion scan protocol has good reproducibility, and as blood flow measurement on FAIR is reliable and closely related with the parameters on DCE-MRI, FAIR is feasible for measuring SBM blood flow. © 2015 Wiley Periodicals, Inc.

  5. Noninvasive blood pressure measurement scheme based on optical fiber sensor

    Science.gov (United States)

    Liu, Xianxuan; Yuan, Xueguang; Zhang, Yangan

    2016-10-01

    Optical fiber sensing has many advantages, such as volume small, light quality, low loss, strong in anti-jamming. Since the invention of the optical fiber sensing technology in 1977, optical fiber sensing technology has been applied in the military, national defense, aerospace, industrial, medical and other fields in recent years, and made a great contribution to parameter measurement in the environment under the limited condition .With the rapid development of computer, network system, the intelligent optical fiber sensing technology, the sensor technology, the combination of computer and communication technology , the detection, diagnosis and analysis can be automatically and efficiently completed. In this work, we proposed a noninvasive blood pressure detection and analysis scheme which uses optical fiber sensor. Optical fiber sensing system mainly includes the light source, optical fiber, optical detector, optical modulator, the signal processing module and so on. wavelength optical signals were led into the optical fiber sensor and the signals reflected by the human body surface were detected. By comparing actual testing data with the data got by traditional way to measure the blood pressure we can establish models for predicting the blood pressure and achieve noninvasive blood pressure measurement by using spectrum analysis technology. Blood pressure measurement method based on optical fiber sensing system is faster and more convenient than traditional way, and it can get accurate analysis results in a shorter period of time than before, so it can efficiently reduce the time cost and manpower cost.

  6. 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)

  7. The effect of dexmedetomidine on cerebral perfusion and oxygenation in healthy piglets with normal and lowered blood pressure anaesthetized with propofol-remifentanil total intravenous anaesthesia

    DEFF Research Database (Denmark)

    Mikkelsen, Mai Louise Grandsgaard; Ambrus, Rikard; Rasmussen, Rune

    2017-01-01

    Background During anaesthesia and surgery, in particular neurosurgery, preservation of cerebral perfusion and oxygenation (CPO) is essential for normal postoperative brain function. The isolated effects on CPO of either individual anaesthetic drugs or entire anaesthetic protocols are of importance...

  8. Magnetic resonance perfusion imaging without contrast media

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  9. Photoacoustic measurements of red blood cell oxygen saturation in blood bags in situ

    Science.gov (United States)

    Pinto, Ruben N.; Bagga, Karan; Douplik, Alexandre; Acker, Jason P.; Kolios, Michael C.

    2017-03-01

    Red blood cell (RBC) transfusion is a critical component of the health care services. RBCs are stored in blood bags in hypothermic temperatures for a maximum of 6 weeks post donation. During this in vitro storage period, RBCs have been documented to undergo changes in structure and function due to mechanical and biochemical stress. Currently, there are no assessment methods that monitor the quality of RBCs within blood bags stored for transfusion. Conventional assessment methods require the extraction of samples, consequently voiding the sterility of the blood bags and potentially rendering them unfit for transfusions. It is hypothesized that photoacoustic (PA) technology can provide a rapid and non-invasive indication of RBC quality. In this study, a novel PA setup was developed for the acquisition of oxygen saturation (SO2) of two blood bags in situ. These measurements were taken throughout the lifespan of the blood bags (42 days) and compared against the clinical gold standard method of the blood gas analyzer (BGA). SO2 values of the blood bags increased monotonically throughout the storage period. A strong correlation between PA SO2 and BGA SO2 was found, however, PA values were on average 3.5% lower. Both techniques found the bags to increase by an SO2 of approximately 20%, and measured very similar rates of SO2 change. Future work will be focused on determining the cause of discrepancy between SO2 values acquired from PA versus BGA, as well as establishing links between the measured SO2 increase and other changes in RBC in situ.

  10. Differences in blood pressure by measurement technique in neurocritically ill patients: A technological assessment.

    Science.gov (United States)

    Lele, Abhijit V; Wilson, Daren; Chalise, Prabhakar; Nazzaro, Jules; Krishnamoorthy, Vijay; Vavilala, Monica S

    2018-01-01

    Blood pressure data may vary by measurement technique. We performed a technological assessment of differences in blood pressure measurement between non-invasive blood pressure (NIBP) and invasive arterial blood pressure (ABP) in neurocritically ill patients. After IRB approval, a prospective observational study was performed to study differences in systolic blood pressure (SBP), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP) values measured by NIBP arm, ABP at level of the phlebostatic axis (ABP heart) and ABP at level of the external auditory meatus (ABP brain) at 30 and 45-degree head of bed elevation (HOB) using repeated measure analysis of covariance and correlation coefficients. Overall, 168 patients were studied with median age of 57 ± 15 years, were mostly female (57%), with body mass index ≤30 (66%). Twenty-three percent (n = 39) had indwelling intracranial pressure monitors, and 19.7% (n = 33) received vasoactive agents. ABP heart overestimated ABP brain for SBP (11.5 ± 2.7 mmHg, p < .001), MAP (mean difference 13.3 ± 0.5 mmHg, p < .001) and CPP (13.4 ± 3.2 mmHg, p < .001). ABP heart overestimated NIBP arm for SBP (8 ± 1.5 mmHg, p < .001), MAP (mean difference 8.6 ± 0.8 mmHg, p < .001), and CPP (mean difference 9.8 ± 3.2 mmHg, p < .001). Regardless of HOB elevation, ABP heart overestimates MAP compared to ABP brain and NIBP arm. Using ABP heart data overestimates CPP and may be responsible for not achieving SBP, MAP or CPP targets aimed at the brain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Effects of Longterm Treatment with Bosentan and Iloprost on Nailfold Absolute Capillary Number, Fingertip Blood Perfusion, and Clinical Status in Systemic Sclerosis.

    Science.gov (United States)

    Trombetta, Amelia Chiara; Pizzorni, Carmen; Ruaro, Barbara; Paolino, Sabrina; Sulli, Alberto; Smith, Vanessa; Cutolo, Maurizio

    2016-11-01

    To quantify in patients with systemic sclerosis (SSc) the absolute nailfold capillary number/mm (the absolute number of capillaries, observable in the first row, in 1 mm per field) and fingertip blood perfusion (FBP) during longterm therapy with the endothelin receptor antagonist bosentan (BOSE) and the synthetic analog of prostacyclin PGI 2 iloprost (ILO) by multiple diagnostic tools. Observed values were correlated with clinical outcomes. Thirty patients with SSc already receiving intravenous ILO (80 μg/day) for 5 continuous days (every 3 mos) were recruited in the clinic. Fifteen patients continued such treatment (ILO group), while in 15 patients BOSE (125 mg twice/day) was added (ILO + BOSE group) because of the onset of pulmonary arterial hypertension or digital ulcers (DU). The followup period was 4 years (T0-T4). Every year the following were evaluated: absolute nailfold capillary number/mm by nailfold videocapillaroscopy, FBP by laser Doppler flowmetry, DU incidence, DLCO, systolic pulmonary arterial pressure (sPAP), renal arterial resistive index, and other biomarkers. From T2 to T4, laser speckled contrast analysis was added. Nonparametric tests were used for statistical analysis. Limited to the ILO + BOSE group, absolute capillary number/mm and FBP showed a progressive increase independently from other variables. In addition, during followup there was a significant reduction (80%) in the incidence of new DU, whereas DLCO and sPAP did not worsen. The study shows in patients with SSc with up to 4 years of combined therapy a progressive significant recovery in structure and function of microvasculature linked to improved clinical outcomes, independent of disease severity.

  12. Monte Carlo estimation of scatter effects on quantitative myocardial blood flow and perfusable tissue fraction using 3D-PET and 15O-water

    Science.gov (United States)

    Hirano, Yoshiyuki; Koshino, Kazuhiro; Watabe, Hiroshi; Fukushima, Kazuhito; Iida, Hidehiro

    2012-11-01

    In clinical cardiac positron emission tomography using 15O-water, significant tracer accumulation is observed not only in the heart but also in the liver and lung, which are partially outside the field-of-view. In this work, we investigated the effects of scatter on quantitative myocardium blood flow (MBF) and perfusable tissue fraction (PTF) by a precise Monte Carlo simulation (Geant4) and a numerical human model. We assigned activities to the heart, liver, and lung of the human model with varying ratios of organ activities according to an experimental time activity curve and created dynamic sinograms. The sinogram data were reconstructed by filtered backprojection. By comparing a scatter-corrected image (SC) with a true image (TRUE), we evaluated the accuracy of the scatter correction. TRUE was reconstructed using a scatter-eliminated sinogram, which can be obtained only in simulations. A scatter-uncorrected image (W/O SC) and an attenuation-uncorrected image (W/O AC) were also constructed. Finally, we calculated MBF and PTF with a single tissue-compartment model for four types of images. As a result, scatter was corrected accurately, and MBFs derived from all types of images were consistent with the MBF obtained from TRUE. Meanwhile, the PTF of only the SC was in agreement with the PTF of TRUE. From the simulation results, we concluded that quantitative MBF is less affected by scatter and absorption in 3D-PET using 15O-water. However, scatter correction is essential for accurate PTF.

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

    International Nuclear Information System (INIS)

    Takasu, Miyuki

    2000-01-01

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

  14. Measurement of the arterial concentration of Gd-DTPA using MRI: a step toward quantitative perfusion imaging

    DEFF Research Database (Denmark)

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

    1996-01-01

    A noninvasive method using an inversion recovery turbo-FLASH for dynamic measurement of the arterial input function represented by the bolus passage of Gd-DTPA in the descending aorta is presented, and the results are compared with the input function obtained by arterial blood samples. A good...... accordance between the two input functions was found, indicating that it is possible to measure the input function to the myocardium using MRI. A variation between the two concentration curves of 5% at upslope, 2.7% at peak point, and ... inversion time peak concentration....

  15. 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...

  16. Quantitation of brain perfusion with {sup 99m}{Tc}-bicisate and single SPECT scan: Comparison with microsphere measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pupi, A.; De Cristofaro, T.R.; Passeri, A.; Castagnoli, A.; Bacciottini, L.; Bottoncetti, A.; Dal Pozzo, G. [Univ. of Florence (Italy); Santoro, G.M.; Antoniucci, D. [USL, Florence (Italy)] [and others

    1994-01-01

    This study describes and validates in a preliminary manner a method to measure the steady-state influx constant (K{sub 1}) of {sup 99m}{Tc}-bicisate with one single photon emission computed tomography (SPECT) scan. The method is based on the analysis of the arterial concentration of the radioactivity. The results of this quantitation procedure were compared with regional CBF (rCBF) measurements made using {sup 99m}{Tc}-microspheres (MI). Two quantitative indexes of perfusion, fractional brain uptake (FBU) and normalized (with cerebellum) brain uptake (NBU), were also evaluated. Two SPECT studies were performed on seven cardiovascular patients who had no signs of neurological disease. In the first of these, {sup 99m}{Tc}-bicisate was used, while in the other, which was performed 2 days later, MI were injected into the left heart ventricle. The values of the FBU, NBU, and K{sub 1} of {sup 99m}{Tc}-bicisate were calculated in several gray and white matter brain regions of interest (ROIs) and compared with the rCBF values measured with MI in coupled ROIs. Mean FBU values were 0.00008 {+-} 0.00002 and 0.00004 {+-} 0.00001 in the gray and the white matter, respectively. Mean NBU values were 0.99 {+-} 0.04 and 0.54 {+-} 0.05, mean K{sub 1} values were 0.36 {+-} 0.06 and 0.19 {+-} 0.03 ml g{sup {minus}1} min{sup {minus}1} and mean rCBF values were 0.51 {+-} 0.04 and 0.27 {+-} 0.04 ml g{sup {minus}1} min{sup {minus}1} in gray and white matter, respectively. Analysis of variance of the regression gave different F values for the regressions with rCBF of FBU (F = 19, n = 126), NBU (F = 289, n = 112), and K{sub 1}(F = 117, n = 112), and K{sub 1}(F = 117, n = 126). The regression of K{sub 1} versus rCBF was K{sub 1} = 0.08 {+-} 0.55 rCBF. 25 refs., 5 figs., 2 tabs.

  17. Comparison of the myocardial blood flow response to regadenoson and dipyridamole: a quantitative analysis in patients referred for clinical 82Rb myocardial perfusion PET

    International Nuclear Information System (INIS)

    Goudarzi, Behnaz; Fukushima, Kenji; Bravo, Paco; Merrill, Jennifer; Bengel, Frank M.

    2011-01-01

    Regadenoson is a novel selective A 2A adenosine receptor agonist, which is administered as an intravenous bolus at a fixed dose. It is currently not clear if the absolute flow increase in response to this fixed dose is a function of distribution volume in individual patients or if it is generally comparable to the previous standard agents dipyridamole or adenosine, which are dosed based on weight. We used quantitative analysis of clinical 82 Rb PET/CT studies to obtain further insights. A total of 104 subjects with normal clinical rest/stress 82 Rb perfusion PET/CT were included in a retrospective analysis. To rule out confounding factors, none had evidence of prior cardiac disease, ischaemia or infarction, cardiomyopathy, diabetes with insulin use, calcium score >400, renal disease or other significant systemic disease. A group of 52 patients stressed with regadenoson were compared with a group of 52 patients stressed with dipyridamole before regadenoson became available. The groups were matched for clinical characteristics, risk factors and baseline haemodynamics. Myocardial blood flow (MBF) and myocardial flow reserve (MFR) were quantified using a previously validated retention model, after resampling of dynamic studies from list-mode 82 Rb datasets. At rest, heart rate, blood pressure and MBF were comparable between the groups. Regadenoson resulted in a significantly higher heart rate (34 ± 14 vs. 23 ± 10 beats per minute increase from baseline; p < 0.01) and rate-pressure product. Patients in the regadenoson group reported less severe symptoms and required less aminophylline. Stress MBF and MFR were not different between the groups (2.2 ± 0.6 vs. 2.1 ± 0.6 ml/min/g, p = 0.39, and 2.9 ± 0.8 vs. 2.8 ± 0.7, p = 0.31, respectively). In the regadenoson group, there was no correlation between stress flow or MFR and body weight or BMI. Despite its administration at a fixed dose, regadenoson results in an absolute increase in MBF which is comparable to that

  18. A novel approach to office blood pressure measurement: 30-minute office blood pressure vs daytime ambulatory blood pressure

    NARCIS (Netherlands)

    Wel, M.C. van der; Buunk, I.E.; Weel, C. van; Thien, Th.; Bakx, J.C.

    2011-01-01

    PURPOSE: Current office blood pressure measurement (OBPM) is often not executed according to guidelines and cannot prevent the white-coat effect. Serial, automated, oscillometric OBPM has the potential to overcome both these problems. We therefore developed a 30-minute OBPM method that we compared

  19. Evaluation of anterior mediastinal solid tumors by CT perfusion: a preliminary study.

    Science.gov (United States)

    Bakan, Selim; Kandemirli, Sedat Giray; Dikici, Atilla Süleyman; Erşen, Ezel; Yıldırım, Onur; Samancı, Cesur; Batur, Şebnem; Çebi Olgun, Deniz; Kantarcı, Fatih; Akman, Canan

    2017-01-01

    We aimed to assess the role of computed tomography (CT) perfusion in differentiation of thymoma from thymic hyperplasia, lymphoma, thymic carcinoma, and lung cancer invading anterior mediastinum. In this study, 25 patients with an anterior mediastinal lesion underwent CT perfusion imaging from January 2015 to February 2016. Diagnoses included thymoma (n=7), thymic hyperplasia (n=8), lymphoma (n=4), thymic carcinoma (n=3), and invasive lung cancer (n=3). Lymphoma, thymic carcinoma, and lung cancer were grouped as malignant tumors for statistical analysis. Values for blood flow, blood volume, and permeability surface were measured in CT perfusion. Blood flow and blood volume values were higher in thymoma in comparison to thymic hyperplasia; however, the difference was not statistically significant. Blood volume values were significantly higher in thymoma (mean, 11.4 mL/100 mL; range, 5.2-20.2 mL/100 mL) compared with lymphoma (mean, 5.3 mL/100 mL; range, 2.5-7.2 mL/100 mL) (P = 0.023). Blood flow and blood volume values were significantly higher in thymoma compared with non-thymoma malignant tumors (P = 0.025). CT perfusion is helpful in differentiating thymoma from non-thymoma malignancies including lymphoma, thymic carcinoma, and invasive lung cancer involving the anterior mediastinum.

  20. In situ mouse carotid perfusion model: glucose and cholesterol transport in the eye and brain.

    Science.gov (United States)

    Cattelotte, Julie; André, Pascal; Ouellet, Mélissa; Bourasset, Fanchon; Scherrmann, Jean-Michel; Cisternino, Salvatore

    2008-08-01

    The in situ mouse brain perfusion method for measuring blood-brain barrier permeability was adapted to assess transport of solutes at the blood-brain and blood-eye barriers. The procedure was checked with radiolabeled markers in oxygenated bicarbonate-buffered fluid infused for 30 to 120 sec via a carotid artery. Vascular flow estimated with diazepam was 2.2-fold lower in the eye than in the brain. The vascular volume and the integrity markers sucrose and inulin indicated that a perfusion flow rate of 2.5 mL/min preserved the physical integrity of these organs. However, the brain vasculature integrity was more sensitive to acute perfusion pressure than the eye vasculature. The functional capacities of blood barriers were assessed with D-glucose; its transport followed Michaelis-Menten kinetics with an apparent K(m) of 7.6 mmol/L and a V(max) of 23 micromol/sec per g in the brain, and a K(m) of 22.9 mmol/L and a V(max) of 40 micromol/sec per g in the eye. The transport of cholesterol to the brain and eye was significantly enhanced by adding the Abca1 inhibitor probucol, suggesting an Abca1-mediated efflux at the mouse brain and eye blood barriers. Thus in situ carotid perfusion is suitable for elucidating transport processes at the blood-brain and blood-eye barriers.

  1. Measurement of testosterone: how important is a morning blood draw?

    Science.gov (United States)

    Crawford, E David; Poage, Wendy; Nyhuis, Allen; Price, David A; Dowsett, Sherie A; Gelwicks, Steven; Muram, David

    2015-01-01

    Since testosterone levels exhibit a circadian variation with peak levels in the morning, evidence-based guidelines recommend measuring morning total testosterone (TT) levels as the initial diagnostic test for androgen deficiency. However, it has been suggested that morning blood draw may not be necessary in older men due to a blunted circadian rhythm. We sought to determine whether it is possible to expand the morning sampling window for measurement of TT. TT levels were measured in a subset of men (mean age of 61 years) participating in the 2013 Prostate Cancer Awareness Week. TT levels measured in blood drawn from 8 to 11 AM (n = 229) differed significantly from those drawn outside this window (n = 442) (411.7 vs 368.3 ng/dl; p = 0.0003). Differences in TT levels were evident across five blood draw time windows (p = < 0.0001) and persisted after adjustment for age and BMI. TT levels in blood drawn from 2 to 5 PM (344.3 ng/dl) and 5 to 8 PM (334.4 ng/dl) differed significantly from that drawn from 8 to 11 AM (p < 0.05), while TT levels from 11 AM to 2 PM (396.5 ng/dl) and 8 PM to 8 AM (373.4 ng/dl) did not (p = 0.90 and 0.73, respectively). Based on these findings, it may be possible to expand the blood draw time window for measurement of serum TT. This community-based study was not prospectively design to determine the most appropriate blood draw window for TT measurement. Only a single TT measurement was made without consideration for day-to-day variability, and TT levels were not measured in the same men at different blood draw times.

  2. 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...

  3. Intravoxel incoherent motion perfusion imaging in acute stroke: initial clinical experience

    International Nuclear Information System (INIS)

    Federau, C.; Becce, F.; Maeder, P.; Meuli, R.; Sumer, S.; Wintermark, M.; O'Brien, K.

    2014-01-01

    Intravoxel incoherent motion (IVIM) imaging is an MRI perfusion technique that uses a diffusion-weighted sequence with multiple b values and a bi-compartmental signal model to measure the so-called pseudo-diffusion of blood caused by its passage through the microvascular network. The goal of the current study was to assess the feasibility of IVIM perfusion fraction imaging in patients with acute stroke. Images were collected in 17 patients with acute stroke. Exclusion criteria were onset of symptoms to imaging >5 days, hemorrhagic transformation, infratentorial lesions, small lesions 2 . Image quality was assessed by two radiologists, and quantitative analysis was performed in regions of interest placed in the stroke area, defined by thresholding the apparent diffusion coefficient maps, as well as in the contralateral region. IVIM perfusion fraction maps showed an area of decreased perfusion fraction f in the region of decreased apparent diffusion coefficient. Quantitative analysis showed a statistically significant decrease in both IVIM perfusion fraction f (0.026 ± 0.019 vs. 0.056 ± 0.025, p = 2.2 . 10 -6 ) and diffusion coefficient D compared with the contralateral side (3.9 ± 0.79 . 10 -4 vs. 7.5 ± 0.86 . 10 -4 mm 2 /s, p = 1.3 . 10 -20 ). IVIM perfusion fraction imaging is feasible in acute stroke. IVIM perfusion fraction is significantly reduced in the visible infarct. Further studies should evaluate the potential for IVIM to predict clinical outcome and treatment response. (orig.)

  4. Development of an Ex-Situ Limb Perfusion System for a Rodent Model.

    Science.gov (United States)

    Gok, Emre; Alghanem, Fares; Moon, Ruth; Guy, Erin; Rojas-Pena, Alvaro; Bartlett, Robert H; Ozer, Kagan

    2018-03-26

    Ex-situ perfusion (ESP) is a promising method in preserving vascularized composite tissue allografts (VCAs) with potential to widen donor procurement to larger geographic areas. To optimize the method of preservation, we developed a small animal model to conduct biomolecular investigations. Twenty rat hind limbs (18.2 ± 1.3 g) were procured and connected to our custom-made ESP system. Perfusion pressure and flow parameters were measured with hourly blood gas analysis under near-normothermic (30-35˚C) conditions. Perfusate was prepared with swine hemoglobin (6-9 g/dL) and STEEN Solution. After 6 hours of perfusion, gastrocnemius muscles were evaluated for their histology and metabolomic profiling. Following 3 sets of experiments, perfusion was maintained at an average flow of 0.9 ± 0.24 mL/min and resulted in lactate levels of 3.78 ± 1.02 mmol/L. Metabolomic analysis revealed maintained cellular energy stores (total adenylates perfusion 0.698 ± 0.052 versus baseline 0.685 ± 0.091 umols/ug, p = 0.831), and histologic analysis revealed no evidence of barotrauma or myodegeneration. Rat hind limbs were viable after 6 hours of ESP on our miniaturized ESP system. This study is the first to document the ex-situ hind limb perfusion platform on a rodent model. These experimental findings have potential to guide future research to extend the viable duration of VCA preservation.

  5. Deeper penetration of erythrocytes into the endothelial glycocalyx is associated with impaired microvascular perfusion.

    Directory of Open Access Journals (Sweden)

    Dae Hyun Lee

    Full Text Available Changes in endothelial glycocalyx are one of the earliest changes in development of cardiovascular disease. The endothelial glycocalyx is both an important biological modifier of interactions between flowing blood and the vessel wall, and a determinant of organ perfusion. We hypothesize that deeper penetration of erythrocytes into the glycocalyx is associated with reduced microvascular perfusion. The population-based prospective cohort study (the Netherlands Epidemiology of Obesity [NEO] study includes 6,673 middle-aged individuals (oversampling of overweight and obese individuals. Within this cohort, we have imaged the sublingual microvasculature of 915 participants using sidestream darkfield (SDF imaging together with a recently developed automated acquisition and analysis approach. Presence of RBC (as a marker of microvascular perfusion and perfused boundary region (PBR, a marker for endothelial glycocalyx barrier properties for RBC accessibility, were assessed in vessels between 5 and 25 µm RBC column width. A wide range of variability in PBR measurements, with a mean PBR of 2.14 µm (range: 1.43-2.86 µm, was observed. Linear regression analysis showed a marked association between PBR and microvascular perfusion, reflected by RBC filling percentage (regression coefficient β: -0.034; 95% confidence interval: -0.037 to -0.031. We conclude that microvascular beds with a thick ("healthy" glycocalyx (low PBR, reflects efficient perfusion of the microvascular bed. In contrast, a thin ("risk" glycocalyx (high PBR is associated with a less efficient and defective microvascular perfusion.

  6. A relative study of hepatic perfusion and portal vein pressure in rats with liver cirrhosis

    International Nuclear Information System (INIS)

    Li Jiaping; Yang Jianyong; Chen Wei; Huang Yonghui

    2006-01-01

    Objective: To evaluate spiral CT perfusion in assessing portal vein pressure in rats with different stages of liver cirrhosis. Methods Seventeen rats with early stage of liver cirrhosis, 18 with intermediate stage, 12 with advanced stage, and 13 healthy rats as a control group were selected and recieved hepatic perfusion on a single-row spiral CT scanner. The parameters of hepatic perfusion were calculated using the deconvolution method. The portal vein pressure was measured by multi-physiographer. Results: (1) In study group, the PVP (portal venous perfusion) and THBP (total hepatic blood perfusion) were negatively correlated with FPP, while positively correlated with the HPI (hepatic perfusion index) and MTT (mean transit time). The FPP had a close relation with PVP. The equation, Y 20.671-3.195X, could be conducted with linear regression analysis. (2) According to the linear regression equation mentioned above, the FPP in 47 rats were 16.090±2.150 cmH 2 0, which was highly correlated with the observed valuel6.108±3.662 cmH 2 O (r=0.823 P<0.01). Conclusion: CT perfusion is a new non-invasive and efficient modality for assessment of the portal pressure in liver cirrhosis in various stages. (authors)

  7. Invasively Measured Aortic Systolic Blood Pressure and Office Systolic Blood Pressure in Cardiovascular Risk Assessment

    DEFF Research Database (Denmark)

    Laugesen, Esben; Knudsen, Søren Tang; Hansen, Klavs Würgler

    2016-01-01

    Aortic systolic blood pressure (BP) represents the hemodynamic cardiac and cerebral burden more directly than office systolic BP. Whether invasively measured aortic systolic BP confers additional prognostic value beyond office BP remains debated. In this study, office systolic BP and invasively m...

  8. Optical techniques for perfusion monitoring of the gastric tube after esophagectomy: a review of technologies and thresholds.

    Science.gov (United States)

    Jansen, S M; de Bruin, D M; van Berge Henegouwen, M I; Strackee, S D; Veelo, D P; van Leeuwen, T G; Gisbertz, S S

    2018-04-26

    Anastomotic leakage is one of the most severe complications after esophageal resection with gastric tube reconstruction. Impaired perfusion of the gastric fundus is seen as the main contributing factor for this complication. Optical modalities show potential in recognizing compromised perfusion in real time, when ischemia is still reversible. This review provides an overview of optical techniques with the aim to evaluate the (1) quantitative measurement of change in perfusion in gastric tube reconstruction and (2) to test which parameters are the most predictive for anastomotic leakage.A Pubmed, MEDLINE, and Embase search was performed and articles on laser Doppler flowmetry (LDF), near-infrared spectroscopy (NIRS), laser speckle contrast imaging (LSCI), fluorescence imaging (FI), sidestream darkfield microscopy (SDF), and optical coherence tomography (OCT) regarding blood flow in gastric tube surgery were reviewed. Two independent reviewers critically appraised articles and extracted the data: Primary outcome was quantitative measure of perfusion change; secondary outcome was successful prediction of necrosis or anastomotic leakage by measured perfusion parameters.Thirty-three articles (including 973 patients and 73 animals) were selected for data extraction, quality assessment, and risk of bias (QUADAS-2). LDF, NIRS, LSCI, and FI were investigated in gastric tube surgery; all had a medium level of evidence. IDEAL stage ranges from 1 to 3. Most articles were found on LDF (n = 12), which is able to measure perfusion in arbitrary perfusion units with a significant lower amount in tissue with necrosis development and on FI (n = 12). With FI blood flow routes could be observed and flow was qualitative evaluated in rapid, slow, or low flow. NIRS uses mucosal oxygen saturation and hemoglobin concentration as perfusion parameters. With LSCI, a decrease of perfusion units is observed toward the gastric fundus intraoperatively. The perfusion units (LDF, LSCI), although

  9. 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.

  10. Refinement of Telemetry for Measuring Blood Pressure in Conscious Rats

    Science.gov (United States)

    Braga, Valdir A; Prabhakar, Nanduri R

    2009-01-01

    Although considered the ‘gold standard’ for measuring blood pressure in laboratory animals, telemetry would benefit from refinement. In the present study, we tested the hypothesis that the small telemetric device used for blood pressure recording in mice would work for rats as well and would serve as an alternative for those studies where abdominal cavity space is quite limited (such as in young animals and pregnant females). Here we report that the use of a smaller and lighter telemetric device implanted in the abdominal aorta of rats led to acquisition of stable and high-quality blood pressure and heart rate data, similar to those obtained by using a larger telemetric device developed for rats. The use of smaller transmitters represents an alternative telemetry technique, especially for those cases in which space in the abdominal cavity is particularly limited such as during pregnancy. PMID:19476715

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

    International Nuclear Information System (INIS)

    Pons, G.

    2011-01-01

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

  13. 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...

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

    International Nuclear Information System (INIS)

    Muessig, K.; Leibniz Center for Diabetes Research, Duesseldorf; University Hospital of Tuebingen; Schraml, C.; Schwenzer, N.F.; University Hospital of Tuebingen; Rietig, R.; Balletshofer, B.; Martirosian, P.; Haering, H.U.; Schick, F.; Claussen, C.D.

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-15

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

  16. Gold-195m: a steady-state imaging agent for venography that gives blood velocity measurement

    Energy Technology Data Exchange (ETDEWEB)

    Dowsett, D.J.; Ennis, J.T.; Collum, C.T.; De Jong, R.B.J.

    1985-08-01

    Gold-195m has found applications in first-pass studies for investigating both right and left ventricular activity as well as lung transit. Owing to its reasonably short half-life of 30 sec the authors have found it particularly useful for imaging leg veins up to and including the inferior vena cava. Its short half-life prevents recirculation activity from appearing, so continuous perfusion into a superficial foot vein and application of ankle tourniquets yield a steady-state image of the deep veins, with particularly good resolution. Its decay pattern along a vessel is very sensitive to blood velocity, so measurement of activity at various points on a vein in a computer static image can give velocity values that reveal abnormalities due to partial or complete thrombosis. The radiation dosimetry of /sup 195m/Au used in this way is lower than contrast and technetium-99m macroaggregated albumin ((/sub 99m/Tc) MAA) venography, making it particularly useful for investigating deep vein thrombosis (DVT) in pregnancy.

  17. Gold-195m: a steady-state imaging agent for venography that gives blood velocity measurement

    International Nuclear Information System (INIS)

    Dowsett, D.J.; Ennis, J.T.; Collum, C.T.; De Jong, R.B.J.

    1985-01-01

    Gold-195m has found applications in first-pass studies for investigating both right and left ventricular activity as well as lung transit. Owing to its reasonably short half-life of 30 sec the authors have found it particularly useful for imaging leg veins up to and including the inferior vena cava. Its short half-life prevents recirculation activity from appearing, so continuous perfusion into a superficial foot vein and application of ankle tourniquets yield a steady-state image of the deep veins, with particularly good resolution. Its decay pattern along a vessel is very sensitive to blood velocity, so measurement of activity at various points on a vein in a computer static image can give velocity values that reveal abnormalities due to partial or complete thrombosis. The radiation dosimetry of /sup 195m/Au used in this way is lower than contrast and technetium-99m macroaggregated albumin ([/sub 99m/Tc] MAA) venography, making it particularly useful for investigating deep vein thrombosis (DVT) in pregnancy

  18. Body mass index and blood pressure measurement during pregnancy.

    LENUS (Irish Health Repository)

    Hogan, Jennifer L

    2012-02-01

    OBJECTIVE: The accurate measurement of blood pressure requires the use of a large cuff in subjects with a high mid-arm circumference (MAC). This prospective study examined the need for a large cuff during pregnancy and its correlation with maternal obesity. METHODS: Maternal body mass index (BMI), fat mass, and MAC were measured. RESULTS: Of 179 women studied, 15.6% were obese. With a BMI of level 1 obesity, 44% needed a large cuff and with a BMI of level 2 obesity 100% needed a large cuff. CONCLUSION: All women booking for antenatal care should have their MAC measured to avoid the overdiagnosis of pregnancy hypertension.

  19. Evaluation of an isotope washout technique to measure skin vascular resistance and skin perfusion pressure: influence of age, site and arterial surgery

    International Nuclear Information System (INIS)

    Duncan, H.J.; Faris, I.B.

    1986-01-01

    1. A simplified isotope (sup(99m)Tc) washout technique has been devised to calculate the skin perfusion pressure (SPP) and skin vascular resistance (SVR). This test is simple, requires inexpensive equipment and is well tolerated by patients. 2. SPP and SVR were calculated in 20 patients 30 years of age and in 15 patients with peripheral vascular disease (PVD). With increasing age the SPP and SVP were increased. The SPP was similar to the mean arterial pressure in normal individuals but was decreased in patients with PVD. The SPP is a useful indicator of the severity of the PVD. 3. The SPP and SVR were higher in the calf than in the foot. This is probably related to the decrease in pressure in the distal arterial tree. 4. SPP was increased by 110% and skin blood flow by 190% by arterial reconstructive surgery. This test may be of use in assessing the effectiveness of arterial surgery. (author)

  20. Delta-projection imaging on contrast-enhanced ultrasound to quantify tumor microvasculature and perfusion.

    Science.gov (United States)

    Sehgal, Chandra M; Cary, Theodore W; Arger, Peter H; Wood, Andrew K W

    2009-01-01

    The aim of this study was to assess the Delta-projection image processing technique for visualizing tumor microvessels and for quantifying the area of tissue perfused by them on contrast-enhanced ultrasound images. The Delta-projection algorithm was implemented to quantify perfusion by tracking the running maximum of the difference (Delta) between the contrast-enhanced ultrasound image sequence and a baseline image. Twenty-five mice with subcutaneous K1735 melanomas were first imaged with contrast-enhanced grayscale and then with minimum-exposure contrast-enhanced power Doppler (minexCPD) ultrasound. Delta-projection images were reconstructed from the grayscale images and then used to evaluate the evolution of tumor vascularity during the course of contrast enhancement. The extent of vascularity (ratio of the perfused area to the tumor area) for each tumor was determined quantitatively from Delta-projection images and compared to the extent of vascularity determined from contrast-enhanced power Doppler images. Delta-projection and minexCPD measurements were compared using linear regression analysis. Delta-projection was successfully performed in all 25 cases. The technique allowed the dynamic visualization of individual blood vessels as they filled in real time. Individual tumor blood vessels were distinctly visible during early image enhancement. Later, as an increasing number of blood vessels were filled with the contrast agent, clusters of vessels appeared as regions of perfusion, and the identification of individual vessels became difficult. Comparisons were made between the perfused area of tumors in Delta-projections and in minexCPD images. The Delta-projection perfusion measurements were correlated linearly with minexCPD. Delta-projection visualized tumor vessels and enabled the quantitative assessment of the tumor area perfused by the contrast agent.

  1. The measurement of blood speed in the pulmonary artery trunk

    International Nuclear Information System (INIS)

    Saro, J.P.; Bula-Cruz, J.; Rafael, J.A.; Botelho, M.F.; Lima, J.P.

    1998-01-01

    The paper describes a non invasive methodology for the measurement of blood speed in the pulmonary artery trunk. The methodology has been tested with a moving radioactive tracer (nuclear medicine). An image processing technique is proposed, for detection and analysis of a moving object with variable shape and intensity over time (radioactive bolus). Experiments on the application of the technique in nuclear medicine are critically analysed. (authors)

  2. Transcutaneous Measurement of Blood Analyte Concentration Using Raman Spectroscopy

    Science.gov (United States)

    Barman, Ishan; Singh, Gajendra P.; Dasari, Ramachandra R.; Feld, Michael S.

    2008-11-01

    Diabetes mellitus is a chronic disorder, affecting nearly 200 million people worldwide. Acute complications, such as hypoglycemia, cardiovascular disease and retinal damage, may occur if the disease is not adequately controlled. As diabetes has no known cure, tight control of glucose levels is critical for the prevention of such complications. Given the necessity for regular monitoring of blood glucose, development of non-invasive glucose detection devices is essential to improve the quality of life in diabetic patients. The commercially available glucose sensors measure the interstitial fluid glucose by electrochemical detection. However, these sensors have severe limitations, primarily related to their invasive nature and lack of stability. This necessitates the development of a truly non-invasive glucose detection technique. NIR Raman Spectroscopy, which combines the substantial penetration depth of NIR light with the excellent chemical specificity of Raman spectroscopy, provides an excellent tool to meet the challenges involved. Additionally, it enables simultaneous determination of multiple blood analytes. Our laboratory has pioneered the use of Raman spectroscopy for blood analytes' detection in biological media. The preliminary success of our non-invasive glucose measurements both in vitro (such as in serum and blood) and in vivo has provided the foundation for the development of feasible clinical systems. However, successful application of this technology still faces a few hurdles, highlighted by the problems of tissue luminescence and selection of appropriate reference concentration. In this article we explore possible avenues to overcome these challenges so that prospective prediction accuracy of blood analytes can be brought to clinically acceptable levels.

  3. Measurement of the distribution of ventilation-perfusion ratios in the human lung with proton MRI: comparison with the multiple inert-gas elimination technique.

    Science.gov (United States)

    Sá, Rui Carlos; Henderson, A Cortney; Simonson, Tatum; Arai, Tatsuya J; Wagner, Harrieth; Theilmann, Rebecca J; Wagner, Peter D; Prisk, G Kim; Hopkins, Susan R

    2017-07-01

    We have developed a novel functional proton magnetic resonance imaging (MRI) technique to measure regional ventilation-perfusion (V̇ A /Q̇) ratio in the lung. We conducted a comparison study of this technique in healthy subjects ( n = 7, age = 42 ± 16 yr, Forced expiratory volume in 1 s = 94% predicted), by comparing data measured using MRI to that obtained from the multiple inert gas elimination technique (MIGET). Regional ventilation measured in a sagittal lung slice using Specific Ventilation Imaging was combined with proton density measured using a fast gradient-echo sequence to calculate regional alveolar ventilation, registered with perfusion images acquired using arterial spin labeling, and divided on a voxel-by-voxel basis to obtain regional V̇ A /Q̇ ratio. LogSDV̇ and LogSDQ̇, measures of heterogeneity derived from the standard deviation (log scale) of the ventilation and perfusion vs. V̇ A /Q̇ ratio histograms respectively, were calculated. On a separate day, subjects underwent study with MIGET and LogSDV̇ and LogSDQ̇ were calculated from MIGET data using the 50-compartment model. MIGET LogSDV̇ and LogSDQ̇ were normal in all subjects. LogSDQ̇ was highly correlated between MRI and MIGET (R = 0.89, P = 0.007); the intercept was not significantly different from zero (-0.062, P = 0.65) and the slope did not significantly differ from identity (1.29, P = 0.34). MIGET and MRI measures of LogSDV̇ were well correlated (R = 0.83, P = 0.02); the intercept differed from zero (0.20, P = 0.04) and the slope deviated from the line of identity (0.52, P = 0.01). We conclude that in normal subjects, there is a reasonable agreement between MIGET measures of heterogeneity and those from proton MRI measured in a single slice of lung. NEW & NOTEWORTHY We report a comparison of a new proton MRI technique to measure regional V̇ A /Q̇ ratio against the multiple inert gas elimination technique (MIGET). The study reports good relationships

  4. Applicability of quantitative optical imaging techniques for intraoperative perfusion diagnostics: a comparison of laser speckle contrast imaging, sidestream dark-field microscopy, and optical coherence tomography

    Science.gov (United States)

    Jansen, Sanne M.; de Bruin, Daniel M.; Faber, Dirk J.; Dobbe, Iwan J. G. G.; Heeg, Erik; Milstein, Dan M. J.; Strackee, Simon D.; van Leeuwen, Ton G.

    2017-08-01

    Patient morbidity and mortality due to hemodynamic complications are a major problem in surgery. Optical techniques can image blood flow in real-time and high-resolution, thereby enabling perfusion monitoring intraoperatively. We tested the feasibility and validity of laser speckle contrast imaging (LSCI), optical coherence tomography (OCT), and sidestream dark-field microscopy (SDF) for perfusion diagnostics in a phantom model using whole blood. Microvessels with diameters of 50, 100, and 400 μm were constructed in a scattering phantom. Perfusion was simulated by pumping heparinized human whole blood at five velocities (0 to 20 mm/s). Vessel diameter and blood flow velocity were assessed with LSCI, OCT, and SDF. Quantification of vessel diameter was feasible with OCT and SDF. LSCI could only visualize the 400-μm vessel, perfusion units scaled nonlinearly with blood velocity. OCT could assess blood flow velocity in terms of inverse OCT speckle decorrelation time. SDF was not feasible to measure blood flow; however, for diluted blood the measurements were linear with the input velocity up to 1 mm/s. LSCI, OCT, and SDF were feasible to visualize blood flow. Validated blood flow velocity measurements intraoperatively in the desired parameter (mL·g-1) remain challenging.

  5. Impact of right-ventricular apical pacing on the optimal left-ventricular lead positions measured by phase analysis of SPECT myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Hung, Guang-Uei; Huang, Jin-Long; Lin, Wan-Yu; Tsai, Shih-Chung; Wang, Kuo-Yang; Chen, Shih-Ann; Lloyd, Michael S.; Chen, Ji

    2014-01-01

    The use of SPECT phase analysis to optimize left-ventricular (LV) lead positions for cardiac resynchronization therapy (CRT) was performed at baseline, but CRT works as simultaneous right ventricular (RV) and LV pacing. The aim of this study was to assess the impact of RV apical (RVA) pacing on optimal LV lead positions measured by SPECT phase analysis. This study prospectively enrolled 46 patients. Two SPECT myocardial perfusion scans were acquired under sinus rhythm with complete left bundle branch block and RVA pacing, respectively, following a single injection of 99m Tc-sestamibi. LV dyssynchrony parameters and optimal LV lead positions were measured by the phase analysis technique and then compared between the two scans. The LV dyssynchrony parameters were significantly larger with RVA pacing than with sinus rhythm (p ∝0.01). In 39 of the 46 patients, the optimal LV lead positions were the same between RVA pacing and sinus rhythm (kappa = 0.861). In 6 of the remaining 7 patients, the optimal LV lead positions were along the same radial direction, but RVA pacing shifted the optimal LV lead positions toward the base. The optimal LV lead positions measured by SPECT phase analysis were consistent, no matter whether the SPECT images were acquired under sinus rhythm or RVA pacing. In some patients, RVA pacing shifted the optimal LV lead positions toward the base. This study supports the use of baseline SPECT myocardial perfusion imaging to optimize LV lead positions to increase CRT efficacy. (orig.)

  6. Hyperpolarized13C urea myocardial first-pass perfusion imaging using velocity-selective excitation.

    Science.gov (United States)

    Fuetterer, Maximilian; Busch, Julia; Peereboom, Sophie M; von Deuster, Constantin; Wissmann, Lukas; Lipiski, Miriam; Fleischmann, Thea; Cesarovic, Nikola; Stoeck, Christian T; Kozerke, Sebastian

    2017-06-21

    A velocity-selective binomial excitation scheme for myocardial first-pass perfusion measurements with hyperpolarized 13 C substrates, which preserves bolus magnetization inside the blood pool, is presented. The proposed method is evaluated against gadolinium-enhanced 1 H measurements in-vivo. The proposed excitation with an echo-planar imaging readout was implemented on a clinical CMR system. Dynamic myocardial stress perfusion images were acquired in six healthy pigs after bolus injection of hyperpolarized 13 C urea with the velocity-selective vs. conventional excitation, as well as standard 1 H gadolinium-enhanced images. Signal-to-noise, contrast-to-noise (CNR) and homogeneity of semi-quantitative perfusion measures were compared between methods based on first-pass signal-intensity time curves extracted from a mid-ventricular slice. Diagnostic feasibility is demonstrated in a case of septal infarction. Velocity-selective excitation provides over three-fold reduction in blood pool signal with a two-fold increase in myocardial CNR. Extracted first-pass perfusion curves reveal a significantly reduced variability of semi-quantitative first-pass perfusion measures (12-20%) for velocity-selective excitation compared to conventional excitation (28-93%), comparable to that of reference 1 H gadolinium data (9-15%). Overall image quality appears comparable between the velocity-selective hyperpolarized and gadolinium-enhanced imaging. The feasibility of hyperpolarized 13 C first-pass perfusion CMR has been demonstrated in swine. Comparison with reference 1 H gadolinium data revealed sufficient data quality and indicates the potential of hyperpolarized perfusion imaging for human applications.

  7. The blood donor identity survey: a multidimensional measure of blood donor motivations.

    Science.gov (United States)

    France, Christopher R; Kowalsky, Jennifer M; France, Janis L; Himawan, Lina K; Kessler, Debra A; Shaz, Beth H

    2014-08-01

    Evidence indicates that donor identity is an important predictor of donation behavior; however, prior studies have relied on diverse, unidimensional measures with limited psychometric support. The goals of this study were to examine the application of self-determination theory to blood donor motivations and to develop and validate a related multidimensional measure of donor identity. Items were developed and administered electronically to a sample of New York Blood Center (NYBC) donors (n=582) and then to a sample of Ohio University students (n=1005). Following initial confirmatory factor analysis (CFA) on the NYBC sample to identify key items related to self-determination theory's six motivational factors, a revised survey was administered to the university sample to reexamine model fit and to assess survey reliability and validity. Consistent with self-determination theory, for both samples CFAs indicated that the best fit to the data was provided by a six-motivational-factor model, including amotivation, external regulation, introjected regulation, identified regulation, integrated regulation, and intrinsic regulation. The Blood Donor Identity Survey provides a psychometrically sound, multidimensional measure of donor motivations (ranging from unmotivated to donate to increasing levels of autonomous motivation to donate) that is suitable for nondonors as well as donors with varying levels of experience. Future research is needed to examine longitudinal changes in donor identity and its relationship to actual donation behavior. © 2014 AABB.

  8. An electronic manometer for blood-pressure measurement.

    Science.gov (United States)

    Burke, M J

    1999-01-01

    This article reports the development of an electronic manometer for use in the measurement of blood pressure. It is intended to act as a replacement gauge for the mercury and aneroid manometers used in conventional sphygmomanometers. It measures pressure in the range 0-300 mm Hg (0-40 kPa) with a resolution of 1 mm Hg (0.13 kPa) and an accuracy of +/- 1 mm Hg (+/- 0.13 kPa) which is displayed on a liquid crystal display. It operates from a 9 V PP3 battery over a temperature range of 10-50 degrees C.

  9. Prospective blood pressure measurement in renal transplant recipients.

    Science.gov (United States)

    David, V G; Yadav, B; Jeyaseelan, L; Deborah, M N; Jacob, S; Alexander, S; Varughese, S; John, G T

    2014-05-01

    Blood pressure (BP) control at home is difficult when managed only with office blood pressure monitoring (OBPM). In this prospective study, the reliability of BP measurements in renal transplant patients with OBPM and home blood pressure monitoring (HBPM) was compared with ambulatory blood pressure monitoring (ABPM) as the gold standard. Adult patients who had living-related renal transplantation from March 2007 to February 2008 had BP measured by two methods; OBPM and ABPM at pretransplantation, 2(nd), 4(th), 6(th), and 9(th) months and all the three methods: OBPM, ABPM, and HBPM at 6 months after transplantation. A total of 49 patients, age 35 ± 11 years, on prednisolone, tacrolimus, and mycophenolate were evaluated. A total of 39 were males (79.6%). Systolic BP (SBP) and diastolic BP (DBP) measured by OBPM were higher than HBPM when compared with ABPM. When assessed using OBPM and awake ABPM, both SBP and DBP were significantly overestimated by OBPM with mean difference of 3-12 mm Hg by office SBP and 6-8 mm Hg for office DBP. When HBPM was compared with mean ABPM at 6 months both the SBP and DBP were overestimated by and 7 mm Hg respectively. At 6 months post transplantation, when compared with ABPM, OBPM was more specific than HBPM in diagnosing hypertension (98% specificity, Kappa: 0.88 vs. 89% specificity, Kappa: 0.71). HBPM was superior to OBPM in identifying patients achieving goal BP (89% specificity, Kappa: 0.71 vs. 50% specificity Kappa: 0.54). In the absence of a gold standard for comparison the latent class model analysis still showed that ABPM was the best tool for diagnosing hypertension and monitoring patients reaching targeted control. OBPM remains an important tool for the diagnosis and management of hypertension in renal transplant recipients. HBPM and ABPM could be used to achieve BP control.

  10. Prospective blood pressure measurement in renal transplant recipients

    Directory of Open Access Journals (Sweden)

    V G David

    2014-01-01

    Full Text Available Blood pressure (BP control at home is difficult when managed only with office blood pressure monitoring (OBPM. In this prospective study, the reliability of BP measurements in renal transplant patients with OBPM and home blood pressure monitoring (HBPM was compared with ambulatory blood pressure monitoring (ABPM as the gold standard. Adult patients who had living-related renal transplantation from March 2007 to February 2008 had BP measured by two methods; OBPM and ABPM at pretransplantation, 2 nd , 4 th , 6 th , and 9 th months and all the three methods : OBPM, ABPM, and HBPM at 6 months after transplantation. A total of 49 patients, age 35 ± 11 years, on prednisolone, tacrolimus, and mycophenolate were evaluated. A total of 39 were males (79.6%. Systolic BP (SBP and diastolic BP (DBP measured by OBPM were higher than HBPM when compared with ABPM. When assessed using OBPM and awake ABPM, both SBP and DBP were significantly overestimated by OBPM with mean difference of 3-12 mm Hg by office SBP and 6-8 mm Hg for office DBP. When HBPM was compared with mean ABPM at 6 months both the SBP and DBP were overestimated by and 7 mm Hg respectively. At 6 months post transplantation, when compared with ABPM, OBPM was more specific than HBPM in diagnosing hypertension (98% specificity, Kappa : 0.88 vs. 89% specificity, Kappa : 0.71. HBPM was superior to OBPM in identifying patients achieving goal BP (89% specificity, Kappa : 0.71 vs. 50% specificity Kappa : 0.54. In the absence of a gold standard for comparison the latent class model analysis still showed that ABPM was the best tool for diagnosing hypertension and monitoring patients reaching targeted control. OBPM remains an important tool for the diagnosis and management of hypertension in renal transplant recipients. HBPM and ABPM could be used to achieve BP control.

  11. 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

  12. 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

  13. 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)

  14. TREATMENT OF HYPERTENSION USING TELEMEDICAL HOME BLOOD PRESSURE MEASUREMENTS

    DEFF Research Database (Denmark)

    Hoffmann-Petersen, N; Lauritzen, T; Bech, J N

    2015-01-01

    of the measurements and subsequent communication by telephone or E-mail. In the control group, patients received usual care. Primary outcome was reduction in daytime ambulatory blood pressure measurements (ABPM) from baseline to 3 months' follow-up. RESULTS: In both groups, daytime ABPM decreased significantly....... The decrease in daytime ABPM in the intervention group was systolic/diastolic, -8  ± 12/-4 ± 7 mmHg. This did not differ significantly from the control group's -8 ± 13/-4 ± 8 mmHg. An equal number of participants obtained normal daytime ABPM, in the intervention group 17% (31/175) versus control 21% (37....../181), p = 0.34. Blood pressure reduction in the TBPM group varied with the different practices. CONCLUSIONS: No further reduction in ABPM or number of patients reaching blood pressure targets was observed when electronic transmission of TBPM was applied in the treatment of hypertension by GPs. Thus...

  15. Microdialysis measurements of lamellar perfusion and energy metabolism during the development of laminitis in the oligofructose model.

    Science.gov (United States)

    Medina-Torres, C E; Underwood, C; Pollitt, C C; Castro-Olivera, E M; Hodson, M P; Richardson, D W; van Eps, A W

    2016-03-01

    Failure of lamellar energy metabolism, with or without ischaemia, may be important in the pathophysiology of sepsis-associated laminitis. To examine lamellar perfusion and energy balance during laminitis development in the oligofructose model using tissue microdialysis. In vivo experiment. Six Standardbred horses underwent laminitis induction using the oligofructose model (OFT group) and 6 horses were untreated controls (CON group). Microdialysis probes were placed in the lamellar tissue of one forelimb (all horses) as well as the skin dermis of the tail in OFT horses. Dialysate and plasma samples were collected every 2 h for 24 h and concentrations of energy metabolites (glucose, lactate, pyruvate) and standard indices of energy metabolism (lactate to glucose ratio [L:G] and lactate to pyruvate ratio [L:P]) determined. Microdialysis urea clearance was used to estimate changes in tissue perfusion. Data were analysed nonparametrically. Median glucose concentration decreased to 5-fold increase in median L:G compared with baseline occurred in OFT lamellar and skin dialysate (Plaminitis in the oligofructose model. Glucose concentrations in the lamellar interstitium decreased, suggesting increased glucose consumption but there was no definitive evidence of lamellar energy failure. © 2015 EVJ Ltd.

  16. 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)

  17. Diagnostic value of transmural perfusion ratio derived from dynamic CT-based myocardial perfusion imaging for the detection of haemodynamically relevant coronary artery stenosis.

    Science.gov (United States)

    Coenen, Adriaan; Lubbers, Marisa M; Kurata, Akira; Kono, Atsushi; Dedic, Admir; Chelu, Raluca G; Dijkshoorn, Marcel L; Rossi, Alexia; van Geuns, Robert-Jan M; Nieman, Koen

    2017-06-01

    To investigate the additional value of transmural perfusion ratio (TPR) in dynamic CT myocardial perfusion imaging for detection of haemodynamically significant coronary artery disease compared with fractional flow reserve (FFR). Subjects with suspected or known coronary artery disease were prospectively included and underwent a CT-MPI examination. From the CT-MPI time-point data absolute myocardial blood flow (MBF) values were temporally resolved using a hybrid deconvolution model. An absolute MBF value was measured in the suspected perfusion defect. TPR was defined as the ratio between the subendocardial and subepicardial MBF. TPR and MBF results were compared with invasive FFR using a threshold of 0.80. Forty-three patients and 94 territories were analysed. The area under the receiver operator curve was larger for MBF (0.78) compared with TPR (0.65, P = 0.026). No significant differences were found in diagnostic classification between MBF and TPR with a territory-based accuracy of 77 % (67-86 %) for MBF compared with 70 % (60-81 %) for TPR. Combined MBF and TPR classification did not improve the diagnostic classification. Dynamic CT-MPI-based transmural perfusion ratio predicts haemodynamically significant coronary artery disease. However, diagnostic performance of dynamic CT-MPI-derived TPR is inferior to quantified MBF and has limited incremental value. • The transmural perfusion ratio from dynamic CT-MPI predicts functional obstructive coronary artery disease • Performance of the transmural perfusion ratio is inferior to quantified myocardial blood flow • The incremental value of the transmural perfusion ratio is limited.

  18. Characteristics of cerebral hemodynamics assessed by CT perfusion in moyamoya disease.

    Science.gov (United States)

    Sasagawa, Ayaka; Mikami, Takeshi; Hirano, Toru; Akiyama, Yukinori; Mikuni, Nobuhiro

    2018-01-01

    Due to the recent development of multidetector row computed tomography (CT), hemodynamic parameters can now be conveniently obtained with CT perfusion. The purpose of this study is to characterize the hemodynamic parameters of CT perfusion in moyamoya disease, and to discuss the differences in collateral circulation between moyamoya disease and atherosclerotic disease. A total of 16 hemispheric sides of 15 patients with moyamoya disease and 10 hemispheric sides of 9 patients with atherosclerotic disease who underwent bypass surgery were included. CT perfusion was performed with 123 I-IMP SPECT. Cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) values obtained by CT perfusion using standard singular value decomposition as the deconvolution algorithm in moyamoya disease were calculated. Preoperative values of these parameters were compared with those of atherosclerotic disease. Then, the postoperative changes of these parameters were analyzed. In the impaired side, CBF as measured by CT perfusion was correlated with that measured by 123 I-IMP SPECT. In moyamoya disease, CBV as measured by CT perfusion was significantly increased compared to in atherosclerotic disease, yet CBF was significantly decreased in atherosclerotic disease. Postoperatively, the asymmetry ratios of MTT were significantly improved, especially in atherosclerotic disease compared with moyamoya disease. On CT perfusion, the parameters included transit time and arrival time. CBV increase in moyamoya disease and postoperative improvement of MTT, especially in atherosclerotic disease, were unique characteristics in each. This might be due to the difference of collateral circulation and compensatory mechanisms between moyamoya disease and atherosclerotic disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Non-invasive assessment of vasospasm following aneurysmal SAH using C-arm FDCT parenchymal blood volume measurement in the neuro-interventional suite: Technical feasibility

    Science.gov (United States)

    Downer, Jonathan; Corkill, Rufus; Byrne, James V

    2015-01-01

    Introduction Cerebral vasospasm is the leading cause of morbidity and mortality in patients with aneurysmal subarachnoid haemorrhage (SAH) surviving the initial ictus. Commonly used techniques for vasospasm assessment are digital subtraction angiography and transcranial Doppler sonography. These techniques can reliably identify only the major vessel spasm and fail to estimate its haemodynamic significance. To overcome these issues and to enable comprehensive non-invasive assessment of vasospasm inside the interventional suite, a novel protocol involving measurement of parenchymal blood volume (PBV) using C-arm flat detector computed tomography (FDCT) was implemented. Materials and methods Patients from the neuro-intensive treatment unit (ITU) with suspected vasospasm following aneurysmal SAH were scanned with a biplane C-arm angiography system using an intravenous contrast injection protocol. The PBV maps were generated using prototype software. Contemporaneous clinically indicated MR scan including the diffusion- and perfusion-weighted sequences was performed. C-arm PBV maps were compared against the MR perfusion maps. Results Distribution of haemodynamic impairment on C-arm PBV maps closely matched the pattern of abnormality on MR perfusion maps. On visual comparison between the two techniques, the extent of abnormality indicated PBV to be both cerebral blood flow and cerebral blood volume weighted. Conclusion C-arm FDCT PBV measurements allow an objective assessment of the severity and localisation of cerebral hypoperfusion resulting from vasospasm. The technique has proved feasible and useful in very sick patients after aneurysmal SAH. The promise shown in this early study indicates that it deserves further evaluation both for post-SAH vasospasm and in other relevant clinical settings. PMID:26017197

  20. Brain perfusion CT compared with ¹⁵O-H₂O PET in patients with primary brain tumours

    DEFF Research Database (Denmark)

    Grüner, Julie Marie; Paamand, Rune Tore; Kosteljanetz, Michael

    2012-01-01

    Perfusion CT (PCT) measurements of regional cerebral blood flow (rCBF) have been proposed as a fast and easy method for identifying angiogenically active tumours. In this study, quantitative PCT rCBF measurements in patients with brain tumours were compared to the gold standard PET rCBF with (15)O...

  1. Validation of myocardial perfusion quantification by dynamic CT in an ex-vivo porcine heart model

    NARCIS (Netherlands)

    Pelgrim, Gert Jan; Das, Marco; van Tuijl, Sjoerd; van Assen, Marly; Prinzen, Frits W; Stijnen, Marco; Oudkerk, Matthijs; Wildberger, Joachim E; Vliegenthart, Rozemarijn

    2017-01-01

    To test the accuracy of quantification of myocardial perfusion imaging (MPI) using computed tomography (CT) in ex-vivo porcine models. Five isolated porcine hearts were perfused according to Langendorff. Hearts were perfused using retrograde flow through the aorta and blood flow, blood pressure and

  2. Magnetic resonance imaging perfusion is associated with disease severity and activity in multiple sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Piotr [Oslo University Hospital, Department of Radiology and Nuclear Medicine, Oslo (Norway); University of Oslo, Institute of Clinical Medicine, Faculty of Medicine, Oslo (Norway); Owren Nygaard, Gro [Oslo University Hospital, Department of Neurology, Oslo (Norway); Bjoernerud, Atle [Intervention Center, Oslo University Hospital, Oslo (Norway); University of Oslo, Department of Physics, Oslo (Norway); Gulowsen Celius, Elisabeth [Oslo University Hospital, Department of Neurology, Oslo (Norway); University of Oslo, Institute of Health and Society, Faculty of Medicine, Oslo (Norway); Flinstad Harbo, Hanne [University of Oslo, Institute of Clinical Medicine, Faculty of Medicine, Oslo (Norway); Oslo University Hospital, Department of Neurology, Oslo (Norway); Kristiansen Beyer, Mona [Oslo University Hospital, Department of Radiology and Nuclear Medicine, Oslo (Norway); Oslo and Akershus University College of Applied Sciences, Department of Life Sciences and Health, Oslo (Norway)

    2017-07-15

    The utility of perfusion-weighted imaging in multiple sclerosis (MS) is not well investigated. The purpose of this study was to compare baseline normalized perfusion measures in subgroups of newly diagnosed MS patients. We wanted to test the hypothesis that this method can differentiate between groups defined according to disease severity and disease activity at 1 year follow-up. Baseline magnetic resonance imaging (MRI) including a dynamic susceptibility contrast perfusion sequence was performed on a 1.5-T scanner in 66 patients newly diagnosed with relapsing-remitting MS. From the baseline MRI, cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) maps were generated. Normalized (n) perfusion values were calculated by dividing each perfusion parameter obtained in white matter lesions by the same parameter obtained in normal-appearing white matter. Neurological examination was performed at baseline and at follow-up approximately 1 year later to establish the multiple sclerosis severity score (MSSS) and evidence of disease activity (EDA). Baseline normalized mean transit time (nMTT) was lower in patients with MSSS >3.79 (p = 0.016), in patients with EDA (p = 0.041), and in patients with both MSSS >3.79 and EDA (p = 0.032) at 1-year follow-up. Baseline normalized cerebral blood flow and normalized cerebral blood volume did not differ between these groups. Lower baseline nMTT was associated with higher disease severity and with presence of disease activity 1 year later in newly diagnosed MS patients. Further longitudinal studies are needed to confirm whether baseline-normalized perfusion measures can differentiate between disease severity and disease activity subgroups over time. (orig.)

  3. Magnetic resonance imaging perfusion is associated with disease severity and activity in multiple sclerosis

    International Nuclear Information System (INIS)

    Sowa, Piotr; Owren Nygaard, Gro; Bjoernerud, Atle; Gulowsen Celius, Elisabeth; Flinstad Harbo, Hanne; Kristiansen Beyer, Mona

    2017-01-01

    The utility of perfusion-weighted imaging in multiple sclerosis (MS) is not well investigated. The purpose of this study was to compare baseline normalized perfusion measures in subgroups of newly diagnosed MS patients. We wanted to test the hypothesis that this method can differentiate between groups defined according to disease severity and disease activity at 1 year follow-up. Baseline magnetic resonance imaging (MRI) including a dynamic susceptibility contrast perfusion sequence was performed on a 1.5-T scanner in 66 patients newly diagnosed with relapsing-remitting MS. From the baseline MRI, cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) maps were generated. Normalized (n) perfusion values were calculated by dividing each perfusion parameter obtained in white matter lesions by the same parameter obtained in normal-appearing white matter. Neurological examination was performed at baseline and at follow-up approximately 1 year later to establish the multiple sclerosis severity score (MSSS) and evidence of disease activity (EDA). Baseline normalized mean transit time (nMTT) was lower in patients with MSSS >3.79 (p = 0.016), in patients with EDA (p = 0.041), and in patients with both MSSS >3.79 and EDA (p = 0.032) at 1-year follow-up. Baseline normalized cerebral blood flow and normalized cerebral blood volume did not differ between these groups. Lower baseline nMTT was associated with higher disease severity and with presence of disease activity 1 year later in newly diagnosed MS patients. Further longitudinal studies are needed to confirm whether baseline-normalized perfusion measures can differentiate between disease severity and disease activity subgroups over time. (orig.)

  4. A study of whole brain perfusion CT and CT angiography in hyperacute and acute cerebral infarction

    International Nuclear Information System (INIS)

    Zhang Yonghai; Bai Junhu; Zhang Ming; Yang Guocai; Tang Guibo; Fang Jun; Shi Wei; Li Xinghua; Liu Suping; Lu Qing; Tang Jun

    2005-01-01

    Objective: To evaluate the diagnostic value of whole-brain perfusion blood volume-weighted CT imaging (PWCT) and simultaneous CT angiography (CTA) on early stage of cerebral ischemic infarction. Methods: Non-contrast CT (NCCT), CT perfusion-weighted imaging (PWCT) and delayed CT (DCT) were conducted on 20 cases of early ischemic infarction of whose onset time ranged from 2 to 24 hours. All cases were reexamined with CT or MRI one week to one month later. CT values and perfusion blood volume (PBV) of central and peripheral low perfusion areas as well as those of collateral side were measured. CTA was reconstructed with PWCT as source images to evaluate occlusion or stenosis of blood vessel, and DCT was used to detect the collateral circulation. Results: Of the 20 cases, NCCT, PWCT and CTA were negative in 10 cases in which 6 were confirmed as Transient Ischemic Attack (TIA) on reexamined CT and clinical features, and the other 4 were confirmed as lacunar infarction. For the remaining 10 cases, a comparison was made with ANOVA between low perfusion area (central, peripheral inside and outside) and collateral side. The difference was significant (P<0.01). However, no significant difference was revealed in the central, peripheral inside and outside areas. PBV values were significant in low perfusion area and collateral side (P<0.05). The area of the final infarction was larger than that of the low perfusion area, and the percentage of enlargement exhibited medium negative correlation to the time of ischemia. CTA indicated that 2 cases suffered from left middle cerebral artery occlusion, meanwhile anterior and middle branches of MCA in the other 3 cases were not identified. The sensitivity of NCCT, PWCT and CTA were 28.5%, 71.4% and 35.7% respectively. DCT indicated that 5 cases had asymmetrical blood vessels. Conclusion: The whole-brain perfusion-weighted CT imaging and simultaneous CT angiography (CTA) is p roved to be a simple, timesaving and effective method for the

  5. Whole brain C-arm computed tomography parenchymal blood volume measurements.

    Science.gov (United States)

    Kamran, Mudassar; Byrne, James V

    2016-04-01

    C-arm flat detector computed tomography (FDCT) parenchymal blood volume (PBV) imaging in the neuro-interventional suite is a new technique for which detailed whole brain measurements have not been previously reported. This study aims to create a catalogue of PBV measurements for various anatomical regions encompassing the whole brain, using a three-dimensional volume-of-interest (3D-VOI) analysis. We acquired and analysed 30 C-arm FDCT datasets from 26 patients with aneurysmal subarachnoid haemorrhage (SAH), as part of a prospective study comparing C-arm computed tomography (CT) PBV with magnetic resonance perfusion-weighted imaging (MR-PWI). We calculated the PBV values for various brain regions with an automated analysis, using 58 pre-defined atlas-based 3D-VOIs encompassing the whole brain. VOIs partially or completely overlapping regions of magnetic resonance diffusion weighted imaging (MR-DWI) abnormality or magnetic resonance cerebral blood flow (MR-CBF) asymmetry were excluded from the analysis. Of the 30 C-arm CT PBV datasets, 14 (54%; 12 patients) had areas of restricted diffusion, the majority of which were focal. The PBV values for the cerebral cortex and cerebral white matter were 4.01 ± 0.47 (mean ± SD) and 3.01 ± 0.39 ml per 100 ml. Lobar PBV values were: frontal lobe 4.2 ± 0.8, temporal lobe 4.2 ± 0.9, parietal lobe 3.9 ± 0.7 and occipital lobe 4.3 ± 0.8 ml/100 ml. The basal ganglia and brainstem PBV values were 3.4 ± 0.7 and 4.6 ± 0.6 ml/100 ml, respectively. Compared with the typical reference cerebral blood volume (CBV) values reported in the literature for Positron Emission Tomography (PET), the PBV values were relatively high for the white matter and relatively low for the cortical grey matter. The reported catalogue of PBV values for various brain regions would be useful to inform future studies and could be used in clinical practice, when interpreting PBV maps. © The Author(s) 2016.

  6. CT Perfusion of the Head

    Science.gov (United States)

    ... Site Index A-Z CT Perfusion of the Head Computed tomography (CT) perfusion of the head uses ... the Head? What is CT Perfusion of the Head? Computed tomography (CT) perfusion imaging shows which areas ...

  7. Out-of-office blood pressure: from measurement to control

    Directory of Open Access Journals (Sweden)

    Baguet JP

    2012-05-01

    Full Text Available Jean-Philippe Baguet1,21Department of Cardiology, University Hospital, 2Bioclinic Radiopharmaceutics Laboratory, INSERM U1039, Joseph Fourier University, Grenoble, FranceAbstract: Hypertension is an important risk factor for the development of cardiovascular disease, and is a major cause of morbidity and mortality worldwide. Traditionally, hypertension diagnosis and treatment and clinical evaluations of antihypertensive efficacy have been based on office blood pressure (BP measurements; however, there is increasing evidence that office measures may provide inadequate or misleading estimates of a patient’s true BP status and level of cardiovascular risk. The introduction, and endorsement by treatment guidelines, of 24-hour ambulatory BP monitoring and self (or home BP monitoring has facilitated more reliable and reproducible estimations of true BP, including the identification of white-coat and masked hypertension, and evaluation of BP variability. In addition, ambulatory BP monitoring enables accurate assessment of treatment effectiveness over 24 hours and both ambulatory and self BP monitoring may lead to better tailoring of therapy according to BP profile and concomitant disease. This review describes the clinical benefits and limitations of out-of-office assessments and their applications for effective management of hypertension and attainment of BP control.Keywords: ambulatory, ABPM, SBPM, blood pressure measurement, hypertension

  8. 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.

  9. Common Genetic Polymorphisms Influence Blood Biomarker Measurements in COPD.

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2016-08-01

    Full Text Available Implementing precision medicine for complex diseases such as chronic obstructive lung disease (COPD will require extensive use of biomarkers and an in-depth understanding of how genetic, epigenetic, and environmental variations contribute to phenotypic diversity and disease progression. A meta-analysis from two large cohorts of current and former smokers with and without COPD [SPIROMICS (N = 750; COPDGene (N = 590] was used to identify single nucleotide polymorphisms (SNPs associated with measurement of 88 blood proteins (protein quantitative trait loci; pQTLs. PQTLs consistently replicated between the two cohorts. Features of pQTLs were compared to previously reported expression QTLs (eQTLs. Inference of causal relations of pQTL genotypes, biomarker measurements, and four clinical COPD phenotypes (airflow obstruction, emphysema, exacerbation history, and chronic bronchitis were explored using conditional independence tests. We identified 527 highly significant (p 10% of measured variation in 13 protein biomarkers, with a single SNP (rs7041; p = 10-392 explaining 71%-75% of the measured variation in vitamin D binding protein (gene = GC. Some of these pQTLs [e.g., pQTLs for VDBP, sRAGE (gene = AGER, surfactant protein D (gene = SFTPD, and TNFRSF10C] have been previously associated with COPD phenotypes. Most pQTLs were local (cis, but distant (trans pQTL SNPs in the ABO blood group locus were the top pQTL SNPs for five proteins. The inclusion of pQTL SNPs improved the clinical predictive value for the established association of sRAGE and emphysema, and the explanation of variance (R2 for emphysema improved from 0.3 to 0.4 when the pQTL SNP was included in the model along with clinical covariates. Causal modeling provided insight into specific pQTL-disease relationships for airflow obstruction and emphysema. In conclusion, given the frequency of highly significant local pQTLs, the large amount of variance potentially explained by pQTL, and the

  10. Comparison of Gated SPECT Myocardial Perfusion Imaging with Echocardiography for the Measurement of Left Ventricular Volumes and Ejection Fraction in Patients With Severe Heart Failure

    Science.gov (United States)

    Shojaeifard, Maryam; Ghaedian, Tahereh; Yaghoobi, Nahid; Malek, Hadi; Firoozabadi, Hasan; Bitarafan-Rajabi, Ahmad; Haghjoo, Majid; Amin, Ahmad; Azizian, Nasrin; Rastgou, Feridoon

    2015-01-01

    Background: Gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is known as a feasible tool for the measurement of left ventricular ejection fraction (EF) and volumes, which are of great importance in the management and follow-up of patients with coronary artery diseases. However, considering the technical shortcomings of SPECT in the presence of perfusion defect, the accuracy of this method in heart failure patients is still controversial. Objectives: The aim of the present study was to compare the results from gated SPECT MPI with those from echocardiography in heart failure patients to compare echocardiographically-derived left ventricular dimension and function data to those from gated SPECT MPI in heart failure patients. Patients and Methods: Forty-one patients with severely reduced left ventricular systolic function (EF ≤ 35%) who were referred for gated SPECT MPI were prospectively enrolled. Quantification of EF, end-diastolic volume (EDV), and end-systolic volume (ESV) was performed by using quantitative gated spect (QGS) (QGS, version 0.4, May 2009) and emory cardiac toolbox (ECTb) (ECTb, revision 1.0, copyright 2007) software packages. EF, EDV, and ESV were also measured with two-dimensional echocardiography within 3 days after MPI. Results: A good correlation was found between echocardiographically-derived EF, EDV, and ESV and the values derived using QGS (r = 0.67, r = 0.78, and r = 0.80 for EF, EDV, and ESV, respectively; P echocardiography. ECTb-derived EDV was also significantly higher than the EDV measured with echocardiography and QGS. The highest correlation between echocardiography and gated SPECT MPI was found for mean values of ESV different. Conclusions: Gated SPECT MPI has a good correlation with echocardiography for the measurement of left ventricular EF, EDV, and ESV in patients with severe heart failure. However, the absolute values of these functional parameters from echocardiography and gated

  11. High-Sodium Diet Has Opposing Effects on Mean Arterial Blood Pressure and Cerebral Perfusion in a Transgenic Mouse Model of Alzheimer's Disease.

    Science.gov (United States)

    Taheri, Saeid; Yu, Jin; Zhu, Hong; Kindy, Mark S

    2016-10-04

    Cerebral ionic homeostasis impairment, especially Ca2+, has been observed in Alzheimer's disease (AD) and also with hypertension. Hypertension and AD both have been implicated in impaired cerebral autoregulation. However, the relationship between the ionic homeostasis impairment in AD and hypertension and cerebral blood flow (CBF) autoregulation is not clear. To test the hypothesis that a high-salt diet regimen influences the accumulation of amyloid-β (Aβand CBF) and CBF, exacerbates cognitive decline, and increases the propensity to AD. Double transgenic mice harboring the amyloid-β protein precursor (APPswe), and presenilin-1 (PSEN1) along with control littermates, 2 months of age at initiation of special diet, were divided into 4 groups: Group A, APP/PS1 and Group B, controls fed a high-sodium (4.00%) chow diet for 3 months; Group C, APP/PS1 and Group D, controls fed a low-sodium (0.08%) regular chow diet for 3 months. Mean arterial blood pressure (MAP) and CBF were measured noninvasively using the tail MAP measurement device and magnetic resonance imaging, respectively. Aβ plaques numbers in the cortex and hippocampus of APP/PS1 were quantified. In contrary to controls, APP/PS1 mice fed a high-salt diet did not show markedly elevated mean systolic and diastolic blood pressure (134±4.8 compared with 162±2.8 mmHg, and 114±5.0 compared with 137±20 mmHg, phigh-salt diet increased CBF in both APP/PS1 and controls and did not alter the cerebral tissue integrity. Aβ plaques were significantly reduced in the cortex and hippocampus of mice fed a high-salt diet. These data suggest that a high-salt diet differently affects MAP and CBF in APP/PS1 mice and controls.

  12. 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

  13. Spatial relationship between tumor perfusion and endogeneous glucose distribution

    International Nuclear Information System (INIS)

    Schroeder, T.; Larrier, N.; Viglianti, B.; Rabbani, Z.N.; Peltz, C.; Vujascovic, Z.; Dewhirst, M.W.

    2003-01-01

    Earlier studies detecting glucose in tissue and solid tumors by bioluminescence imaging suggested, that glucose distribution patterns may be spatially related to functional vascularity. The purpose of this study was to evaluate this relationship by comparing glucose distribution patterns as determined by bioluminescence imaging to perfusion patterns of endogeneous Hoechst 33342 in rats bearing mammary carcinomas. R 3230 mammary carcinoma cells have been implanted subcutaneously into 7 female Fischer 344 rats. Two months post implantation, after injection of Hoechst 33342 the tumors were removed and snap frozen to conserve metabolite levels. Concomitantly, blood was sampled from the animals for analysis of glucose concentrations using a micodialysis analyzer. Cryosections of the tumors have been prepared, and every slice has been analyzed for both, Hoechst binding by fluorescence microscopy, and for glucose distribution patterns using bioluminescence imaging. In many cases vascular structures could be retrieved by the spatial pattern of glucose distribution. In some cases however, higher glucose concentrations could be found independent from Hoechst signal. On the other hand, regions of high Hoechst signal are not necessarily correlated with high glucose concentrations. When comparing blood and tissue glucose levels, tissue glucose content as measured with bioluminescence imaging (1.9-3.5 mM) is considerably lower than blood glucose (5.6-8.0 mM), demonstrating the expected gradient from blood to tissue. This study demonstrates the feasibility of monitoring glucose gradients in relation to functional vasculature throughout the body, from blood down to tissue or tumor and further, throughout the microenvironment of the solid tumor. Glucose distribution patterns may be an important tool in perfusion studies, e. g. in detecting the direction of blood flow in ex-vivo samples or in estimating glucose consumption rates of tumor cells adjacent to or in between perfused

  14. Comparison of Regional Brain Perfusion Levels in Chronically Smoking and Non-Smoking Adults

    Directory of Open Access Journals (Sweden)

    Timothy C. Durazzo

    2015-07-01

    Full Text Available Chronic cigarette smoking is associated with numerous abnormalities in brain neurobiology, but few studies specifically investigated the chronic effects of smoking (compared to the acute effects of smoking, nicotine administration, or nicotine withdrawal on cerebral perfusion (i.e., blood flow. Predominately middle-aged male (47 ± 11 years of age smokers (n = 34 and non-smokers (n = 27 were compared on regional cortical perfusion measured by continuous arterial spin labeling magnetic resonance studies at 4 Tesla. Smokers showed significantly lower perfusion than non-smokers in the bilateral medial and lateral orbitofrontal cortices, bilateral inferior parietal lobules, bilateral superior temporal gyri, left posterior cingulate, right isthmus of cingulate, and right supramarginal gyrus. Greater lifetime duration of smoking (adjusted for age was related to lower perfusion in multiple brain regions. The results indicated smokers showed significant perfusion deficits in anterior cortical regions implicated in the development, progression, and maintenance of all addictive disorders. Smokers concurrently demonstrated reduced blood flow in posterior brain regions that show morphological and metabolic aberrations as well as elevated beta amyloid deposition demonstrated by those with early stage Alzheimer disease. The findings provide additional novel evidence of the adverse effects of cigarette smoking on the human brain.

  15. The future of the perfusion record: automated data collection vs. manual recording.

    Science.gov (United States)

    Ottens, Jane; Baker, Robert A; Newland, Richard F; Mazzone, Annette

    2005-12-01

    The perfusion record, whether manually recorded or computer generated, is a legal representation of the procedure. The handwritten perfusion record has been the most common method of recording events that occur during cardiopulmonary bypass. This record is of significant contrast to the integrated data management systems available that provide continuous collection of data automatically or by means of a few keystrokes. Additionally, an increasing number of monitoring devices are available to assist in the management of patients on bypass. These devices are becoming more complex and provide more data for the perfusionist to monitor and record. Most of the data from these can be downloaded automatically into online data management systems, allowing more time for the perfusionist to concentrate on the patient while simultaneously producing a more accurate record. In this prospective report, we compared 17 cases that were recorded using both manual and electronic data collection techniques. The perfusionist in charge of the case recorded the perfusion using the manual technique while a second perfusionist entered relevant events on the electronic record generated by the Stockert S3 Data Management System/Data Bahn (Munich, Germany). Analysis of the two types of perfusion records showed significant variations in the recorded information. Areas that showed the most inconsistency included measurement of the perfusion pressures, flow, blood temperatures, cardioplegia delivery details, and the recording of events, with the electronic record superior in the integrity of the data. In addition, the limitations of the electronic system were also shown by the lack of electronic gas flow data in our hardware. Our results confirm the importance of accurate methods of recording of perfusion events. The use of an automated system provides the opportunity to minimize transcription error and bias. This study highlights the limitation of spot recording of perfusion events in the

  16. Pulmonary vascular volume ratio measured by cardiac computed tomography in children and young adults with congenital heart disease: comparison with lung perfusion scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo; Park, Sang Hyub [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of)

    2017-11-15

    Lung perfusion scintigraphy is regarded as the gold standard for evaluating differential lung perfusion ratio in congenital heart disease. To compare cardiac CT with lung perfusion scintigraphy for estimated pulmonary vascular volume ratio in patients with congenital heart disease. We included 52 children and young adults (median age 4 years, range 2 months to 28 years; 31 males) with congenital heart disease who underwent cardiac CT and lung perfusion scintigraphy without an interim surgical or transcatheter intervention and within 1 year. We calculated the right and left pulmonary vascular volumes using threshold-based CT volumetry. Then we compared right pulmonary vascular volume percentages at cardiac CT with right lung perfusion percentages at lung perfusion scintigraphy by using paired t-test and Bland-Altman analysis. The right pulmonary vascular volume percentages at cardiac CT (66.3 ± 14.0%) were significantly smaller than the right lung perfusion percentages at lung perfusion scintigraphy (69.1 ± 15.0%; P=0.001). Bland-Altman analysis showed a mean difference of -2.8 ± 5.8% and 95% limits of agreement (-14.1%, 8.5%) between these two variables. Cardiac CT, in a single examination, can offer pulmonary vascular volume ratio in addition to pulmonary artery anatomy essential for evaluating peripheral pulmonary artery stenosis in patients with congenital heart disease. However there is a wide range of agreement between cardiac CT and lung perfusion scintigraphy. (orig.)

  17. Noninvasive quantification of myocardial perfusion heterogeneity by Markovian analysis in SPECT nuclear imaging; Quantification non invasive de l'heterogeneite de la perfusion du myocarde par analyse markovienne en imageries nucleaire SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Pons, G.

    2011-04-28

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

  18. Hyperventilation, cerebral perfusion, and syncope

    DEFF Research Database (Denmark)

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

    2014-01-01

    the contribution of a low PaCO2 to the early postural reduction in middle cerebral artery blood velocity is transient. HV together with postural stress does not reduce cerebral perfusion to such an extent that TLOC develops. However when HV is combined with cardiovascular stressors like cold immersion or reduced...... dioxide (PaCO2) and oxygen (PaO2) partial pressures so that hypercapnia/hypoxia increases and hypocapnia/hyperoxia reduces global cerebral blood flow. Cerebral hypoperfusion and TLOC have been associated with hypocapnia related to HV. Notwithstanding pronounced cerebrovascular effects of PaCO2...

  19. Blood Density Is Nearly Equal to Water Density: A Validation Study of the Gravimetric Method of Measuring Intraoperative Blood Loss.

    Science.gov (United States)

    Vitello, Dominic J; Ripper, Richard M; Fettiplace, Michael R; Weinberg, Guy L; Vitello, Joseph M

    2015-01-01

    Purpose. The gravimetric method of weighing surgical sponges is used to quantify intraoperative blood loss. The dry mass minus the wet mass of the gauze equals the volume of blood lost. This method assumes that the density of blood is equivalent to water (1 gm/mL). This study's purpose was to validate the assumption that the density of blood is equivalent to water and to correlate density with hematocrit. Methods. 50 µL of whole blood was weighed from eighteen rats. A distilled water control was weighed for each blood sample. The averages of the blood and water were compared utilizing a Student's unpaired, one-tailed t-test. The masses of the blood samples and the hematocrits were compared using a linear regression. Results. The average mass of the eighteen blood samples was 0.0489 g and that of the distilled water controls was 0.0492 g. The t-test showed P = 0.2269 and R (2) = 0.03154. The hematocrit values ranged from 24% to 48%. The linear regression R (2) value was 0.1767. Conclusions. The R (2) value comparing the blood and distilled water masses suggests high correlation between the two populations. Linear regression showed the hematocrit was not proportional to the mass of the blood. The study confirmed that the measured density of blood is similar to water.

  20. Cerebral blood oxygenation measurements in neonates with optoacoustic technique

    Science.gov (United States)

    Herrmann, Stephen; Petrov, Irene Y.; Petrov, Yuriy; Richardson, C. Joan; Fonseca, Rafael A.; Prough, Donald S.; Esenaliev, Rinat O.

    2017-03-01

    Cerebral hypoxia is a major contributor to neonatal/infant mortality and morbidity including severe neurological complications such as mental retardation, cerebral palsy, motor impairment, and epilepsy. Currently, no technology is capable of accurate monitoring of neonatal cerebral oxygenation. We proposed to use optoacoustics for this application by probing the superior sagittal sinus (SSS), a large central cerebral vein. We developed and built a multi-wavelength, optical parametric oscillator (OPO) and laser diode optoacoustic systems for measurement of SSS blood oxygenation in the reflection mode through open anterior or posterior fontanelles and in the transmission mode through the skull in the occipital area. In this paper we present results of initial tests of the laser diode system for neonatal cerebral oxygenation measurements. First, the system was tested in phantoms simulating neonatal SSS. Then, using the data obtained in the phantoms, we optimized the system's hardware and software and tested it in neonates admitted in the Neonatal Intensive Care Unit. The laser diode system was capable of detecting SSS signals in the reflection mode through the open anterior and posterior fontanelles as well as in the transmission mode through the skull with high signal-to-noise ratio. Using the signals measured at different wavelengths and algorithms developed for oxygenation measurements, the laser diode system provided real-time, continuous oxygenation monitoring with high precision at all these locations.

  1. Combination of phlebography and sanguinous measurement of venous blood pressure

    International Nuclear Information System (INIS)

    Weber, J.

    1988-01-01

    Phlebographic visualisation offers the highest spatial resolution of all imaging methods both in respect of veins of the leg and pelvis and of the abdomen. Phlebography offers optimal conditions for assessing morphological changes at the veins and in their direct neighbourhood. No quantitative information is available via phlebography if haemodynamics are disturbed; qualitative information is yielded merely to a restricted extent (by assessing flow velocity and collaterals). Direct sanguinous measurement of venous blood pressure is particularly suitable for the quantitative and qualitative assessment of disturbed haemodynamic conditions; in this respect it stands out among the function tests based on the employment of apparatures. If it is combined with phlebography, it is possible not only to optimise the diagnostic yield in the hands of one investigator, but also to reduce the invasiveness of both methods to one single puncture, since the puncture needle is at the same time also an instrument to measure the pressure. The article points out the possibilities and limitations of combining a) ascending phlebography of the leg and pelvis with peripheral venous pressure measurement (phlebodynamometry) and b) visualisation of the veins of the pelvis and vena cava inferior with central sanguinous venous pressure measurement (CP). Indicatious and technical execution are described. (orig.) [de

  2. A pitfall in the measurement of arterial blood pressure in the ischaemic limb during elevation

    DEFF Research Database (Denmark)

    Bülow, J; Jelnes, Rolf

    1987-01-01

    In order to evaluate if elevation of the ischaemic limb above heart level is an alternative to the conventionally applied method with external counterpressure for estimation of skin perfusion pressure, femoral and popliteal artery pressures were measured directly in eight patients with occlusion ...... extremity cannot be determined non-invasively by elevation of the extremity, probably due to collapse of segments of the vascular bed increasing the vascular resistance considerably....

  3. Comparison of spectroscopically measured tissue alcohol concentration to blood and breath alcohol measurements

    Science.gov (United States)

    Ridder, Trent D.; Ver Steeg, Benjamin J.; Laaksonen, Bentley D.

    2009-09-01

    Alcohol testing is an expanding area of interest due to the impacts of alcohol abuse that extend well beyond drunk driving. However, existing approaches such as blood and urine assays are hampered in some testing environments by biohazard risks. A noninvasive, in vivo spectroscopic technique offers a promising alternative, as no body fluids are required. The purpose of this work is to report the results of a 36-subject clinical study designed to characterize tissue alcohol measured using near-infrared spectroscopy relative to venous blood, capillary blood, and breath alcohol. Comparison of blood and breath alcohol concentrations demonstrated significant differences in alcohol concentration [root mean square of 9.0 to 13.5 mg/dL] that were attributable to both assay accuracy and precision as well as alcohol pharmacokinetics. A first-order kinetic model was used to estimate the contribution of alcohol pharmacokinetics to the differences in concentration observed between the blood, breath, and tissue assays. All pair-wise combinations of alcohol assays were investigated, and the fraction of the alcohol concentration variance explained by pharmacokinetics ranged from 41.0% to 83.5%. Accounting for pharmacokinetic concentration differences, the accuracy and precision of the spectroscopic tissue assay were found to be comparable to those of the blood and breath assays.

  4. 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

  5. Magnetic resonance first-pass perfusion imaging: overview and perspectives.

    Science.gov (United States)

    Zenovich, A; Muehling, O M; Panse, P M; Jerosch-Herold, M; Wilke, N

    2001-01-01

    The data from clinical studies with quantitative MR first-pass perfusion imaging suggests that this technique outperforms SPECT--widely available clinical imaging tool--in sensitivity and specificity. Moreover, MRFP imaging may be combined with the assessment of global and segmental function of the heart and regional wall thickening, and in addition, performed with pharmacological stress agents. The inter- and intra-observer reproducibility of quantitative MRFP is comparable with clinically used nuclear medicine techniques. MRFP measurements can discern collateral myocardium and are able to identify small changes in myocardial blood flow and myocardial perfusion reserve (the ratio of stress blood flow over resting). MRFP imaging has been mainly used in context of coronary artery disease but many other exciting areas in clinical cardiology are awaiting of new insights that can be accomplished with this technique. Trials are needed to obtain the approval of the contrast agent (Gd-DTPA) and perfusion sequences by the Food and Drug Administration and to establish reimbursement procedures with the third-party insurance companies and health maintenance organizations.

  6. Measurements of enlarged blood pump models using Laser Doppler Anemometer.

    Science.gov (United States)

    Chua, L P; Yu, S C; Leo, H L

    2000-01-01

    In an earlier study (Chua et al., 1998, 1999a), a 5:1 enlarged model of the Kyoto-NTN Magnetically Suspended Centrifugal Blood Pump (Akamatsu et al., 1995) with five different impeller blade profiles was designed and constructed. Their respective flow characteristics with respect to (1) the three different blade profile designs: forward, radial, and backward, (2) the number of blades used, and (3) the rotating speed were investigated. Among the five impeller designs, the results obtained suggested that impellers A and C designs should be adopted if higher head is required. Impellers A and C therefore were selected for the flow in between their blades to be measured using Laser Doppler Anemometer (LDA), so as to have a better understanding of the flow physics with respect to the design parameters.

  7. 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

  8. 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.

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