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Sample records for blood volume measured

  1. Transcutaneous measurement of volume blood flow

    Science.gov (United States)

    Daigle, R. E.; Mcleod, F. D.; Miller, C. W.; Histand, M. B.; Wells, M. K.

    1974-01-01

    Blood flow velocity measurements, using Doppler velocimeter, are described. The ability to measure blood velocity using ultrasound is derived from the Doppler effect; the change in frequency which occurs when sound is reflected or transmitted from a moving target. When ultrasound of the appropriate frequency is transmitted through a moving blood stream, the blood cells act as point scatterers of ultrasonic energy. If this scattered ultrasonic energy is detected, it is found to be shifted in frequency according to the velocity of the blood cells, nu, the frequency of the incident sound, f sub o, the speed of sound in the medium, c, and the angle between the sound beam and the velocity vector, o. The relation describing this effect is known as the Doppler equation. Delta f = 2 f sub o x nu x cos alpha/c. The theoretical and experimental methods are evaluated.

  2. 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 relat

  3. On-line dynamic measurement of blood viscosity, hematocrit and change of blood volume

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To develop an on-line system for the measurement of blood viscosity and hematocrit. The dynamic changes of the macrovascular blood volumes,microvascular blood volumes and the total blood volume were observed by means of calculating from the testing result. Methods: Applying traditional viscosity measurement principle and specific wavelength optic density measurement method, an on-line system for the measurement of blood viscosity and hematocrit was developed, and the A/D multifunctionai board and the testing circuit were designed by ourselves. The system was validated by experiments both in vitro and in vivo. Therapeutic effects of hypertonic saline dextran solution (HSD) and Lactatic Ringer's solution at the early stage after burn-blast combined injury were compared by this method. Results: The results showed that the system has attained the goal of the design. The changes of the blood viscosity and hematocrit could be detected effectively and continuously. The changes of macrovascular, microvascular and total blood volume could be calculated approximately. Conclusions: The system and the method can continuously on-line test the blood viscosity and hematocrit, and reveal the change and distribution of blood volumes more accurately and dearly in the therapy process by estimating changes of the macrovascular, microvascular and total blood volumes, respectively. It has confirmed that HSD treatment could increase blood pressure and attenuate tissue edema by significantly increasing total blood volume,improving macrocirculatory and microcirculatory blood volumes. This study suggested that it could be desirable to develop an experiment technique based on the method mentioned above.

  4. Blood volume measurement with indocyanine green pulse spectrophotometry: dose and site of dye administration

    NARCIS (Netherlands)

    M.R. Germans; P.C. de Witt Hamer; L.J. van Boven; K.A.H. Zwinderman; G.J. Bouma

    2010-01-01

    (1) To determine the optimal administration site and dose of indocyanine green (ICG) for blood volume measurement using pulse spectrophotometry, (2) to assess the variation in repeated blood volume measurements for patients after subarachnoid hemorrhage and (3) to evaluate the safety and efficacy of

  5. Can cerebral blood volume be measured reproducibly with an improved near infrared spectroscopy system?

    NARCIS (Netherlands)

    Ven, M.T.P. van de; Colier, W.N.J.M.; Sluijs, M.C. van der; Walraven, D.; Oeseburg, B.; Folgering, H.T.M.

    2001-01-01

    In some circumstances, cerebral blood volume (CBV) can be used as a measure for cerebral blood flow. A new near infrared spectroscope was used for determining the reproducibility of CBV measurements assessed by the O2-method. Twenty-seven healthy subjects were investigated. An intrasubject coefficie

  6. Quantitative absorption cytometry for measuring red blood cell hemoglobin mass and volume.

    Science.gov (United States)

    Schonbrun, Ethan; Malka, Roy; Di Caprio, Giuseppe; Schaak, Diane; Higgins, John M

    2014-04-01

    We present an optical system, called the quantitative absorption cytometer (QAC), to measure the volume and hemoglobin mass of red blood cells flowing through a microfluidic channel. In contrast to clinical hematology analyzers, where cells are sphered in order for both volume and hemoglobin to be measured accurately, the QAC measures cells in their normal physiological shape. Human red blood cells are suspended in a refractive index-matching absorbing buffer, driven through a microfluidic channel, and imaged using a transmission light microscope onto a color camera. A red and a blue LED illuminate cells and images at each color are used to independently retrieve cell volume and hemoglobin mass. This system shows good agreement with red blood cell indices retrieved by a clinical hematology analyzer and in fact measures a smaller coefficient of variation of hemoglobin concentration. In addition to cell indices, the QAC returns height and mass maps of each measured cell. These quantitative images are valuable for analyzing the detailed morphology of individual cells as well as statistical outliers found in the data. We also measured red blood cells in hypertonic and hypotonic buffers to quantify the correlation between volume and hemoglobin mass under osmotic stress. Because this method is invariant to cell shape, even extremely nonspherical cells in hypertonic buffers can be measured accurately.

  7. Portal blood flow volume measurement in schistosomal patients: evaluation of Doppler ultrasonography reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    Leao, Alberto Ribeiro de Souza; Santos, Jose Eduardo Mourao; Moulin, Danilo Sales; Shigueoka, David Carlos; D' Ippolito, Giuseppe [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Escola Paulista de Medicina. Dept. de Diagnostico por Imagem]. E-mail: ar.leao@uol.com.br; Colleoni, Ramiro [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Escola Paulista de Medicina. Dept. de Gastroenterologia

    2008-09-15

    Objective: To evaluate the reproducibility of Doppler ultrasonography in the measurement of portal blood flow volume in schistosomal patients. Materials and methods: Prospective, transversal, observational and self-paired study evaluating 21 patients with hepatosplenic schistosomiasis submitted to Doppler ultrasonography performed by three independent observers for measurement of portal blood flow. Pairwise interobserver agreement was calculated by means of the intraclass correlation coefficient, paired t-test and Pearson's correlation coefficient. Results: Interobserver agreement was excellent. Intraclass correlation ranged from 80.6% to 93.0% (IC at 95% [65.3% ; 95.8%]), with the Pearson's correlation coefficient ranging between 81.6% and 92.7% with no statistically significant interobserver difference regarding the mean portal blood flow volume measured by Doppler ultrasonography (p = 0.954 / 0.758 / 0.749). Conclusion: Doppler ultrasonography has demonstrated to be a reliable method for measuring the portal blood flow volume in patients with portal hypertension secondary to schistosomiasis, with a good interobserver agreement. (author)

  8. Human cerebral blood volume measurements using dynamic contrast enhancement in comparison to dynamic susceptibility contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Moran [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Liberman, Gilad; Vitinshtein, Faina; Aizenstein, Orna [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Nadav, Guy [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Faculty of Engineering, Tel Aviv (Israel); Blumenthal, Deborah T.; Bokstein, Felix [Tel Aviv Sourasky Medical Center, Neuro-Oncology Service, Tel Aviv (Israel); Bashat, Dafna Ben [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv (Israel)

    2015-07-15

    Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (v{sub p}) can also be extracted from dynamic contrast enhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. v{sub p} and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between v{sub p} and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

  9. Validation of a continuous penile blood-flow measurement by pulse-volume-plethysmography.

    Science.gov (United States)

    Lavoisier, P; Barbe, R; Gally, M

    2002-04-01

    Today, in the assessment of cavernous artery blood-flow, the most commonly used technique is Doppler ultrasound velocimetry (continuous, pulsed, color-coded or power), which is often considered as the gold standard. Plethysmographic techniques and radioactive tracers have been widely used for the assessment of global penis flow variations but are not adequate for continuous blood-flow measurement. A new pulse-volume plethysmographic (PVP) device using a water-filled penile cuff was employed to assess continuous blood-flow measurement in the penis. Simultaneously Doppler velocity was recorded and served as a gold standard. A penile water-cuff is connected through a pressure tube to a three-way tap. The pulse-volume changes in the penile water-cuff are measured by means of a latex membrane placed over one of the three-way taps. The displacements of the latex are recorded by a photoplethysmograph. The third tap is connected to a 5 l perfusion bag placed 30 cm above the penis so as to maintain constant pressure in the whole device whatever the penis volume. Twenty-four volunteers were tested. The Doppler velocity signal and pulse volume of cavernous arteries were measured simultaneously after PGE1 intra-cavernous injection. Blood-flow variations were induced by increasing penis artery compression with a second penile water-cuff used as a tourniquet fitted onto the penis root, and the pressure of which could be modified by a water-filled syringe. The amplitude of the plethysmographic pulse-volume signal and the area under the Doppler velocity signal were correlated. The inter-patient (n=24) correlation ranged from 0.455 to 0.904, with a mean correlation of 0.704 and P<0.0001. PVP measurement by a water-filled cuff was validated by ultrasound velocimetry. This new continuous, non-invasive and easy-to-use technique enables physiological and physiopathological flow-measurement during sleep, under visual sexual stimulation (VSS), or following artificial erection

  10. Reduced central blood volume in cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Bendtsen, Flemming; Sørensen, T I

    1989-01-01

    for measuring the central blood volume. We have developed a method that enables us to determine directly the central blood volume, i.e., the blood volume in the heart cavities, lungs, and central arterial tree. In 60 patients with cirrhosis and 16 control subjects the central blood volume was assessed according...

  11. Absolute cerebral blood flow and blood volume measured by magnetic resonance imaging bolus tracking: comparison with positron emission tomography values

    DEFF Research Database (Denmark)

    Østergaard, Leif; Smith, D F; Vestergaard-Poulsen, Peter;

    1998-01-01

    The authors determined cerebral blood flow (CBF) with magnetic resonance imaging (MRI) of contrast agent bolus passage and compared the results with those obtained by O-15 labeled water (H215O) and positron emission tomography (PET). Six pigs were examined by MRI and PET under normo......- and hypercapnic conditions. After dose normalization and introduction of an empirical constant phi Gd, absolute regional CBF was calculated from MRI. The spatial resolution and the signal-to-noise ratio of CBF measurements by MRI were better than by the H215O-PET protocol. Magnetic resonance imaging cerebral...... blood volume (CBV) estimates obtained using this normalization constant correlated well with values obtained by O-15 labeled carbonmonooxide (C15O) PET. However, PET CBV values were approximately 2.5 times larger than absolute MRI CBV values, supporting the hypothesized sensitivity of MRI to small...

  12. Calculation of the Residual Blood Volume after Acute, Non-Ongoing Hemorrhage Using Serial Hematocrit Measurements and the Volume of Isotonic Fluid Infused: Theoretical Hypothesis Generating Study.

    Science.gov (United States)

    Oh, Won Sup; Chon, Sung-Bin

    2016-05-01

    Fluid resuscitation, hemostasis, and transfusion is essential in care of hemorrhagic shock. Although estimation of the residual blood volume is crucial, the standard measuring methods are impractical or unsafe. Vital signs, central venous or pulmonary artery pressures are inaccurate. We hypothesized that the residual blood volume for acute, non-ongoing hemorrhage was calculable using serial hematocrit measurements and the volume of isotonic solution infused. Blood volume is the sum of volumes of red blood cells and plasma. For acute, non-ongoing hemorrhage, red blood cell volume would not change. A certain portion of the isotonic fluid would increase plasma volume. Mathematically, we suggest that the residual blood volume after acute, non-ongoing hemorrhage might be calculated as 0·25N/[(Hct1/Hct2)-1], where Hct1 and Hct2 are the initial and subsequent hematocrits, respectively, and N is the volume of isotonic solution infused. In vivo validation and modification is needed before clinical application of this model.

  13. Accurate measurement of volume and shape of resting and activated blood platelets from light scattering.

    Science.gov (United States)

    Moskalensky, Alexander E; Yurkin, Maxim A; Konokhova, Anastasiya I; Strokotov, Dmitry I; Nekrasov, Vyacheslav M; Chernyshev, Andrei V; Tsvetovskaya, Galina A; Chikova, Elena D; Maltsev, Valeri P

    2013-01-01

    We introduce a novel approach for determination of volume and shape of individual blood platelets modeled as an oblate spheroid from angle-resolved light scattering with flow-cytometric technique. The light-scattering profiles (LSPs) of individual platelets were measured with the scanning flow cytometer and the platelet characteristics were determined from the solution of the inverse light-scattering problem using the precomputed database of theoretical LSPs. We revealed a phenomenon of parameter compensation, which is partly explained in the framework of anomalous diffraction approximation. To overcome this problem, additional a priori information on the platelet refractive index was used. It allowed us to determine the size of each platelet with subdiffraction precision and independent of the particular value of the platelet aspect ratio. The shape (spheroidal aspect ratio) distributions of platelets showed substantial differences between native and activated by 10 μM adenosine diphosphate samples. We expect that the new approach may find use in hematological analyzers for accurate measurement of platelet volume distribution and for determination of the platelet activation efficiency.

  14. Accurate measurement of volume and shape of resting and activated blood platelets from light scattering

    Science.gov (United States)

    Moskalensky, Alexander E.; Yurkin, Maxim A.; Konokhova, Anastasiya I.; Strokotov, Dmitry I.; Nekrasov, Vyacheslav M.; Chernyshev, Andrei V.; Tsvetovskaya, Galina A.; Chikova, Elena D.; Maltsev, Valeri P.

    2013-01-01

    We introduce a novel approach for determination of volume and shape of individual blood platelets modeled as an oblate spheroid from angle-resolved light scattering with flow-cytometric technique. The light-scattering profiles (LSPs) of individual platelets were measured with the scanning flow cytometer and the platelet characteristics were determined from the solution of the inverse light-scattering problem using the precomputed database of theoretical LSPs. We revealed a phenomenon of parameter compensation, which is partly explained in the framework of anomalous diffraction approximation. To overcome this problem, additional a priori information on the platelet refractive index was used. It allowed us to determine the size of each platelet with subdiffraction precision and independent of the particular value of the platelet aspect ratio. The shape (spheroidal aspect ratio) distributions of platelets showed substantial differences between native and activated by 10 μM adenosine diphosphate samples. We expect that the new approach may find use in hematological analyzers for accurate measurement of platelet volume distribution and for determination of the platelet activation efficiency.

  15. Optimal velocity encoding during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography

    Institute of Scientific and Technical Information of China (English)

    Gang Guo; Yonggui Yang; Weiqun Yang

    2011-01-01

    This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 ± 118 mL/min, and the outflow volume was 506 ± 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60-80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.

  16. Quantitative measurements of cerebral blood flow in volume imaging PET scanners

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.J.; Shao, L.; Freifelder, R.; Karp, J.S.; Ragland, J.D. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    1995-08-01

    Quantitative measurements of Cerebral Blood Flow (CBF) are performed in a volume imaging PET Scanner by means of moderate activity infusions. In equilibrium infusions, activations are measured by scanning over 10 minutes with 16 minute activations. Typical measured whole brain CBF values are 37{+-}8 ml/min/100g, close to the value of 42 ml/min/100g reported by other groups using this method. For ramped infusions, scanning over 4 minutes with 5 minute activations results in whole brain CBFs of 49 {+-} 9 ml/min/100g, close to the Kety and Schmidt value of 50 ml/min/100g. Both equilibrium and ramped infusion methods have been used to study face and word memory in human subjects. Both methods were able to detect significant activations in regions implicated in human memory. The authors conclude that precise quantitation of regional CBF is achieved using both methods, and that ramped infusions also provide accurate measures of CBF. In addition a simplified protocol for ramped infusion studies has been developed. In this method the whole brain tissue time activity curve generated from dynamic scanning is replaced by an appropriately scaled camera coincidence countrate curve. The resulting whole brain CBF values are only 7% different from the dynamic scan and fit results. Regional CBFs (rCBF) may then be generated from the summed image (4.25 minutes) using a count density vs flow lookup table.

  17. Suitable image parameters and analytical method for quantitatively measuring cerebral blood flow volume with phase-contrast magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Handa H

    1999-02-01

    Full Text Available The aim of this study was to determine suitable image parameters and an analytical method for phase-contrast magnetic resonance imaging (PC-MRI as a means of measuring cerebral blood flow volume. This was done by constructing an experimental model and applying the results to a clinical application. The experimental model was constructed from the aorta of a bull and circulating isotonic saline. The image parameters of PC-MRI (repetition time, flip angle, matrix, velocity rate encoding, and the use of square pixels were studied with percent flow volume (the ratio of actual flow volume to measured flow volume. The most suitable image parameters for accurate blood flow measurement were as follows: repetition time, 50 msec; flip angle, 20 degrees; and a 512 x 256 matrix without square pixels. Furthermore, velocity rate encoding should be set ranging from the maximum flow velocity in the vessel to five times this value. The correction in measuring blood flow was done with the intensity of the region of interest established in the background. With these parameters for PC-MRI, percent flow volume was greater than 90%. Using the image parameters for PC-MRI and the analytical method described above, we evaluated cerebral blood flow volume in 12 patients with occlusive disease of the major cervical arteries. The results were compared with conventional xenon computed tomography. The values found with both methods showed good correlation. Thus, we concluded that PC-MRI was a noninvasive method for evaluating cerebral blood flow in patients with occlusive disease of the major cervical arteries.

  18. Reduced central blood volume in cirrhosis

    DEFF Research Database (Denmark)

    Bendtsen, F; Henriksen, Jens Henrik Sahl; Sørensen, T I

    1989-01-01

    for measuring the central blood volume. We have developed a method that enables us to determine directly the central blood volume, i.e., the blood volume in the heart cavities, lungs, and central arterial tree. In 60 patients with cirrhosis and 16 control subjects the central blood volume was assessed according......The pathogenesis of ascites formation in cirrhosis is uncertain. It is still under debate whether the effective blood volume is reduced (underfilling theory) or whether the intravascular compartment is expanded (overflow theory). This problem has not yet been solved because of insufficient tools...... to the kinetic theory as the product of cardiac output and mean transit time of the central vascular bed. Central blood volume was significantly smaller in patients with cirrhosis than in controls (mean 21 vs. 27 ml/kg estimated ideal body weight, p less than 0.001; 25% vs. 33% of the total blood volume, p less...

  19. 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...

  20. Forearm skin tissue dielectric constant measured at 300 MHz: effect of changes in skin vascular volume and blood flow.

    Science.gov (United States)

    Mayrovitz, Harvey N; Guo, Xiaoran; Salmon, Mark; Uhde, Matt

    2013-01-01

    Skin tissue dielectric constant (TDC) values measured via the open-ended coaxial probe method are useful non-invasive indices of local skin tissue water. However, the effect of skin blood flow (SBF) or skin blood volume (SBV) on TDC values is unknown. To determine the magnitude of such effects, we decreased forearm SBV via vertical arm raising for 5 min (test 1) and increased SBV by bicep cuff compression to 50 mmHg for 5 min (test 2) in 20 healthy supine subjects (10 men). TDC values were measured to a depth of 1·5 mm on anterior forearm, and SBF was measured with laser-Doppler system simultaneously on forearm and finger. Results indicate that decreasing vascular volume (test 1) was associated with a small but statistically significant reduction in TDC (3·0 ± 4·3%, P = 0·003) and increasing vascular volume (test 2) was associated with a slight but statistically significant increase in TDC (3·5 ± 3·0%, PTDC values (3·0-3·5%) over the wide range of induced SBV and SBF changes suggest a minor effect on clinically determined TDC values because of SBV or SBF changes or differences when comparing TDC longitudinally over time or among individuals of different groups in a research setting.

  1. Comparison of two flow-based imaging methods to measure individual red blood cell area and volume.

    Science.gov (United States)

    Tomaiuolo, Giovanna; Rossi, Domenico; Caserta, Sergio; Cesarelli, Mario; Guido, Stefano

    2012-12-01

    The red blood cells (RBCs) population is characterized by a high heterogeneity in membrane area, cellular volume, and mechanical properties, mainly due to the variety of mechanical and chemical stresses that a red cell undergoes in its entire life span. Here, we provide the first simultaneous area and volume measurements of RBCs flowing in microcapillaries, by using high-speed video microscopy imaging and quantitative data processing based on image analysis techniques. Both confined and unbounded flow conditions (depending on the relative size of RBCs and microcapillary diameter) are investigated. The results are compared with micropipette experiments from the literature and data from Coulter counter routine clinical blood tests. Good agreement is found for RBC volume, especially in the case of confined flow conditions. Surface area measurements, which are lacking in the routine clinical test, are of special interest being a potential diagnostic parameter of altered cell deformability and aggregability. Overall, our results provide a novel flow methodology suitable for high-throughput measurements of RBC geometrical parameters, allowing one to overcome the limits of classical static methods, such as micropipette aspiration, which are not suitable for handling a large number of cells.

  2. Noninvasive blood flow measurement and quantification of shunt volume by cine magnetic resonance in congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Sieverding, L.; Apitz, J. (Tuebingen Univ. (Germany). Abt. fuer Paediatrische Kardiologie); Jung, W.I. (Tuebingen Univ. (Germany). Abt. fuer Paediatrische Kardiologie Tuebingen Univ. (Germany). Physikalisches Inst.); Klose, U. (Tuebingen Univ. (Germany). Medizinisches Strahleninstitut und Roentgenabteilung)

    1992-04-01

    Based on the phase difference method as described by Nayler et al. we developed a gradient-echo sequence, which refocuses flow related phase shifts even for infants with their higher peak velocity, higher acceleration and faster heart rates. A repetition time (TR) of 15 ms provides a high temporal resolution for dynamic studies. Modification of the flow-rephasing gradient-echo sequence in slice select direction leads to a defined phase shift and the resultant phase difference images allow blood flow measurements in the great arteries and the calculation of blood volume per heart cycle (flow volume) to assess left and right ventricular stroke volume. This can also be achieved by calculation of the ventricular volume from contiguous slices of the whole heart, but, this in excessive measuring times. Both methods were applied in 6 examinations of children with congenital heart diseases (1 pulmonary sling, 1 coarctation of the aorta, 1 ventricular septal defect, 3 atrial septal defects). The age of the patients ranged from 3 months to 13.4 years (mean age 4.9 years). The regression analyses of both methods show a high correlation for systemic flow (y=-0.98+1.08 x, r=0.99, SEE=2.59 ml) and for pulmonary flow (y=-1.40+0.96 x, r=0.99, SEE=4.70 ml). The comparison of flow calculated Qp:Qs ratio and chamber size calculated Qp:Qs ratio with data obtained by heart catheterization show also a regression line close to the line of identity (y=-0.01+1.04 x, r=0.98, SEE=0.15 and y=0.28+0.96 x, r=0.81, SEE=0.47, respectively). (orig.).

  3. Blood pressure measurement

    Science.gov (United States)

    Diastolic blood pressure; Systolic blood pressure; Blood pressure reading; Measuring blood pressure ... or your health care provider will wrap the blood pressure cuff snugly around your upper arm. The lower ...

  4. Peripheral arterial volume distensibility: significant differences with age and blood pressure measured using an applied external pressure.

    Science.gov (United States)

    Zheng, Dingchang; Murray, Alan

    2011-05-01

    A new arterial distensibility measurement technique was assessed in 100 healthy normotensive subjects. Arterial transmural pressures on the whole right arm were reduced with a 50 cm long cuff inflated to 10, 20, 30 and 40 mmHg. The electrocardiogram, and finger and ear photoplethysmograms were recorded simultaneously. Arm pulse propagation time, pulse wave velocity (PWV) and arterial volume distensibility were determined. With a 40 mmHg reduction in transmural pressure, arm pulse propagation time increased from 61 to 83 ms, PWV decreased from 12 to 8 m s(-1) and arterial distensibility increased from 0.102% to 0.232% per mmHg (all P pressures, arterial distensibility was significantly related to resting mean arterial pressure (MAP), diastolic blood pressure (DBP) and age, and for systolic blood pressure at 30 and 40 mmHg (all P pressure, arterial distensibility fell by 54% for a MAP increase from 75 to 105 mmHg, 57% for a DBP increase from 60 to 90 mmHg and 47% for an age increase from 20 to 70 years. These changes were more than double than those without cuff pressure. Our technique showed that systemic volume distensibility of the peripheral arm artery reduced with age, with a greater effect at higher external and lower transmural pressures.

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

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, H. (Den Sundhedsfaglige Kandidatuddannelse, Aarhus Universitet Bygning 1264, Aarhus (Denmark); University College Nordjylland, Aalborg (Denmark)), Email: hnt@ucn.dk; Steffensen, E. (Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark)); Larsson, E. M. (Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark); Uppsala University Hospital, Department of Radiology, Uppsala (Sweden))

    2012-02-15

    Background. Perfusion magnetic resonance imaging (MRI) is increasingly used in the evaluation of brain tumors. Relative cerebral blood volume (rCBV) is usually obtained by dynamic susceptibility contrast (DSC) MRI using normal appearing white matter as reference region. The emerging perfusion 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-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 rCBV maps, with contralateral normal appearing white matter and cerebellum as reference regions. Larger ROIs were drawn for histogram analyses. The type and grade of the gliomas were obtained by histopathology. Statistical comparison was made between diffuse astrocytomas, anaplastic astrocytomas, and glioblastomas. Results. rCBF and rCBV measurements obtained with the maximum perfusion method were correlated when normalized to white matter (r = 0.60) and to the cerebellum (r = 0.49). Histogram analyses of rCBF and rCBV showed that mean and median values as well as skewness and peak position were correlated (0.61 < r < 0.93), whereas for kurtosis and peak height, the correlation coefficient was about 0.3 when comparing rCBF and rCBV values for the same reference region. Neither rCBF nor rCBV quantification provided a statistically significant difference between the three types of gliomas. However, both rCBF and rCBV tended to increase with tumor grade and to be lower in patients who had undergone resection/treatment. Conclusion. rCBF measurements normalized to white matter

  6. Pulmonary intravascular blood volume changes through the cardiac cycle in healthy volunteers studied by cardiovascular magnetic resonance measurements of arterial and venous flow

    Directory of Open Access Journals (Sweden)

    Arheden Hakan

    2009-10-01

    Full Text Available Abstract Background This study aims to present a novel method for using cardiovascular magnetic resonance (CMR to non-invasively quantify the variation in pulmonary blood volume throughout the cardiac cycle in humans. Methods 10 healthy volunteers (7 males, 3 female, age range 21-32 years were studied. The blood flow in the pulmonary artery and all pulmonary veins was quantified during free breathing using phase contrast velocity encoded CMR. The difference in flow between the pulmonary artery and the pulmonary veins was integrated to calculate the change in pulmonary blood volume throughout the cardiac cycle. Results The stroke volumes in the pulmonary artery and the sum of the pulmonary veins were (mean ± SEM 103 ± 6 ml and 95 ± 6 ml, respectively. The pulmonary blood volume variation (PBVV was 48 ± 5 ml, and the PBVV expressed as percent of the pulmonary artery stroke volume was 46 ± 3%. The maximum increase in pulmonary blood volume occurred 310 ± 12 ms after the R-wave from the ECG (32 ± 2% of the cardiac cycle. PBVV did not correlate to change in cross-sectional area in the pulmonary artery (R2 = 0.03, p = 0.66. Conclusion It is feasible to non-invasively quantify the change in pulmonary blood volume during the cardiac cycle in humans using CMR. The average pulmonary blood volume variation in healthy volunteers was approximately 50 ml and this was approximately 50% of the stroke volume. Further studies are needed to assess the utility of the pulmonary blood volume variation as a measure for identifying cardiac and pulmonary vascular disease.

  7. Non-invasive cerebral blood volume measurement during seizures using multi-channel near infrared spectroscopic topography

    Science.gov (United States)

    Watanabe, Eiju; Maki, Atsushi; Kawaguchi, Fumio; Yamashita, Yuichi; Koizumi, Hideaki; Mayanagi, Yoshiaki

    2000-07-01

    Near infrared spectroscopic topography (NIRS) is widely recognized as a noninvasive method to measure the regional cerebral blood volume (rCBV) dynamics coupled with neuronal activities. We analyzed the rCBV change in the early phase of epileptic seizures in 12 consecutive patients with medically intractable epilepsy. Seizure was induced by bemegride injection. We used eight-channel NIRS in nine cases and 24 channel in three cases. In all of the cases, rCBV increased rapidly after the seizure onset on the focus side. The increased rCBV was observed for about 30 - 60 s. The NIRS method can be applied to monitor the rCBV change continuously during seizures. Therefore, this method may be combined with ictal SPECT as one of the most reliable noninvasive methods of focus diagnosis.

  8. 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

    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...

  9. Intraprocedural blood volume measurement using C-arm CT as a predictor for treatment response of malignant liver tumours undergoing repetitive transarterial chemoembolization (TACE)

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, Thomas J.; Schaefer, Patrik; Lehnert, Thomas; Mbalisike, Emmanuel; Hammerstingl, Renate; Eichler, Katrin; Zangos, Stephan [Johann Wolfgang Goethe-University Frankfurt, Institute for Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Nour-Eldin, Nour-Eldin A. [Johann Wolfgang Goethe-University Frankfurt, Institute for Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Cairo University, Department of Radiology, Faculty of Medicine (Kasr Al-Ainy), Cairo (Egypt); Ackermann, Hanns [Johann Wolfgang Goethe-University Frankfurt, Department of Biomedical Statistics, Frankfurt am Main (Germany); Naguib, Nagy N.N. [Johann Wolfgang Goethe-University Frankfurt, Institute for Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Alexandria University, Department of Radiology, Faculty of Medicine, Alexandria (Egypt)

    2016-03-15

    To evaluate feasibility of measuring parenchymal blood volume (PBV) of malignant hepatic tumours using C-arm CT, test the changes in PBV following repeated transarterial chemoembolization (TACE) and correlate these changes with the change in tumour size in MRI. 111 patients with liver malignancy were included. Patients underwent MRI and TACE in a 4- to 6-week interval. During intervention C-arm CT was performed. Images were post-processed to generate PBV maps. Blood volume data in C-arm CT and change in size in MRI were evaluated. The correlation between PBV and size was tested using Spearman rank test. Pre-interventional PBV maps showed a mean blood volume of 84.5 ml/1000 ml ± 62.0, follow-up PBV maps after multiple TACE demonstrated 61.1 ml/1000 ml ± 57.5. The change in PBV was statistically significant (p = 0.02). Patients with initial tumour blood volume >100 ml/1000 ml dropped 7.1 % in size and 47.2 % in blood volume; 50-100 ml/1000 ml dropped 4.6 % in size and 25.7 % in blood volume; and <50 ml/1000 ml decreased 2.8 % in size and increased 82.2 % in blood volume. PBV measurement of malignant liver tumours using C-arm CT is feasible. Following TACE PBV decreased significantly. Patients with low initial PBV show low local response rates and further increase in blood volume, whereas high initial tumour PBV showed better response to TACE. (orig.)

  10. Dose reduction in dynamic perfusion CT of the brain: effects of the scan frequency on measurements of cerebral blood flow, cerebral blood volume, and mean transit time

    Energy Technology Data Exchange (ETDEWEB)

    Wiesmann, Martin [University of Munich, Department of Neuroradiology, Muenchen (Germany); Klinikum der Universitaet Muenchen - Grosshadern, Abteilung fuer Neuroradiologie, Muenchen (Germany); Berg, Scott; Stoeckelhuber, B.M. [University of Luebeck, Department of Radiology, Luebeck (Germany); Bohner, G.; Klingebiel, R. [University Medicine Berlin, Department of Neuroradiology, Charite, Berlin (Germany); Schoepf, V.; Yousry, I.; Linn, J. [University of Munich, Department of Neuroradiology, Muenchen (Germany); Missler, U. [Evangelisches Krankenhaus Duisburg-Nord, Department of Neuroradiology, Duisburg (Germany)

    2008-12-15

    The influence of the frequency of computed tomography (CT) image acquistion on the diagnostic quality of dynamic perfusion CT (PCT) studies of the brain was investigated. Eight patients with clinically suspected acute ischemia of one hemisphere underwent PCT, performed on average 3.4 h after the onset of symptoms. Sixty consecutive images per slice were obtained with individual CT images obtained at a temporal resolution of two images per second. Eight additional data sets were reconstructed with temporal resolutions ranging from one image per second to one image per 5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) measurements were performed in identical regions of interest. Two neuroradiologists evaluated the PCT images visually to identify areas of abnormal perfusion. Perfusion images created up to a temporal resolution of one image per 3 s were rated to be diagnostically equal to the original data. Even at one image per 4 s, all areas of infarction were identified. Quantitative differences of CBF, CBV and MTT measurements were {<=}10% up to one image per 3 s. For PCT of the brain, temporal resolution can be reduced to one image per 3 s without significant compromise in image quality. This significantly reduces the radiation dose of the patient. (orig.)

  11. Detecting variations of blood volume shift due to heart beat from respiratory inductive plethysmography measurements in man.

    Science.gov (United States)

    Fontecave-Jallon, J; Videlier, B; Baconnier, P; Tanguy, S; Calabrese, P; Guméry, P-Y

    2013-09-01

    The simultaneous study of the cardiac and respiratory activities and their interactions is of great physiological and clinical interest. For this purpose, we want to investigate if respiratory inductive plethysmography (RIP) can be used for cardiac functional exploration. We propose a system, based on RIP technology and time-scale approaches of signal processing, for the extraction of cardiac information. This study focuses on the monitoring of blood volume shift due to heart beat, noted ▵Vtr_c and investigates RIP for the detection of ▵Vtr_c variations by comparison to stroke volume (SV) variations estimated by impedance cardiography (IMP). We proposed a specific respiratory protocol assumed to induce significant variations of the SV. Fifteen healthy volunteers in the seated and supine positions were asked to alternate rest respiration and maneuvers, consisting in blowing into a manometer. A multi-step treatment including a variant of empirical mode decomposition was applied on RIP signals to extract cardiac volume signals and estimate beat-to-beat ▵Vtr_c. These were averaged in quasi-stationary states at rest and during the respiratory maneuvers, and analysed in view of SV estimations from IMP signals simultaneously acquired. Correlation and statistical tests over the data show that RIP can be used to detect variations of the cardiac blood shift in healthy young subjects.

  12. Precision volume measurement system.

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Erin E.; Shugard, Andrew D.

    2004-11-01

    A new precision volume measurement system based on a Kansas City Plant (KCP) design was built to support the volume measurement needs of the Gas Transfer Systems (GTS) department at Sandia National Labs (SNL) in California. An engineering study was undertaken to verify or refute KCP's claims of 0.5% accuracy. The study assesses the accuracy and precision of the system. The system uses the ideal gas law and precise pressure measurements (of low-pressure helium) in a temperature and computer controlled environment to ratio a known volume to an unknown volume.

  13. Novel system using microliter order sample volume for measuring arterial radioactivity concentrations in whole blood and plasma for mouse PET dynamic study.

    Science.gov (United States)

    Kimura, Yuichi; Seki, Chie; Hashizume, Nobuya; Yamada, Takashi; Wakizaka, Hidekatsu; Nishimoto, Takahiro; Hatano, Kentaro; Kitamura, Keishi; Toyama, Hiroshi; Kanno, Iwao

    2013-11-21

    This study aimed to develop a new system, named CD-Well, for mouse PET dynamic study. CD-Well allows the determination of time-activity curves (TACs) for arterial whole blood and plasma using 2-3 µL of blood per sample; the minute sample size is ideal for studies in small animals. The system has the following merits: (1) measures volume and radioactivity of whole blood and plasma separately; (2) allows measurements at 10 s intervals to capture initial rapid changes in the TAC; and (3) is compact and easy to handle, minimizes blood loss from sampling, and delay and dispersion of the TAC. CD-Well has 36 U-shaped channels. A drop of blood is sampled into the opening of the channel and stored there. After serial sampling is completed, CD-Well is centrifuged and scanned using a flatbed scanner to define the regions of plasma and blood cells. The length measured is converted to volume because the channels have a precise and uniform cross section. Then, CD-Well is exposed to an imaging plate to measure radioactivity. Finally, radioactivity concentrations are computed. We evaluated the performance of CD-Well in in vitro measurement and in vivo (18)F-fluorodeoxyglucose and [(11)C]2-carbomethoxy-3β-(4-fluorophenyl) tropane studies. In in vitro evaluation, per cent differences (mean±SE) from manual measurement were 4.4±3.6% for whole blood and 4.0±3.5% for plasma across the typical range of radioactivity measured in mouse dynamic study. In in vivo studies, reasonable TACs were obtained. The peaks were captured well, and the time courses coincided well with the TAC derived from PET imaging of the heart chamber. The total blood loss was less than 200 µL, which had no physiological effect on the mice. CD-Well demonstrates satisfactory performance, and is useful for mouse PET dynamic study.

  14. EFFECTS OF A BASKETBALL ACTIVITY ON LUNG CAPILLARY BLOOD VOLUME AND MEMBRANE DIFFUSING CAPACITY, MEASURED BY NO/CO TRANSFER IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Rim Dridi

    2006-09-01

    Full Text Available In both children and adults, acute exercise increases lung capillary blood volume (Vc and membrane factor (DmCO. We sought to determine whether basketball training affected this adaptation to exercise in children. The purpose of this study was to determine the effects of two years sport activity on the components of pulmonary gas transfer in children. Over a 2-yr period, we retested 60 nine year old boys who were initially separated in two groups: 30 basketball players (P (9.0 ± 1.0 yrs; 35.0 ± 5.2 kg; 1.43 ± 0.05 m, and matched non players controls (C (8.9 ± 1.0 yrs; 35.0 ± 6.0 kg; 1.44 ± 0.06 m who did not perform any extracurricular activity, Vc and DmCO were measured by the NO/CO transfer method at rest and during sub-maximal exercise. Maximal aerobic power and peak power output was 12% higher in the trained group compared to matched controls (p < 0.05. Nitric oxide lung transfer (TLNO per unit lung volume and thus, DmCO per unit of lung volume (VA were higher at rest and during exercise in the group which had undergone regular basketball activity compared to matched controls (p < 0.05. Neither lung capillary blood volume nor total lung transfer for carbon monoxide (TLCO were significantly different between groups. These results suggest that active sport can alter the properties of the lung alveolo-capillary membrane by improving alveolar membrane conductance in children

  15. Cerebral blood flow volume measurements of the carotid artery and ipsilateral branches using two-dimensional phase-contrast magnetic resonance angiography

    Institute of Scientific and Technical Information of China (English)

    Gang Guo; Yonggui Yang; Weiqun Yang

    2011-01-01

    The optimal velocity encoding of phase-contrast magnetic resonance angiography (PC MRA) in measuring cerebral blood flow volume (BFV) ranges from 60 to 80 cm/s. To verify the accuracy of two-dimensional (2D) PC MRA, the present study localized the region of interest at blood vessels of the neck using PC MRA based on three-dimensional time-of-flight sequences, and the velocity encodingwas set to 80 cm/s. Results of the measurements showed that the error rate was 7.0 ± 6.0%in the estimation of BFV in the internal carotid artery, the external carotid artery and the ipsilateralcommon carotid artery. There was no significant difference, and a significant correlation in BFV between internal carotid artery + external carotid artery and ipsilateral common carotid artery. Inaddition, the BFV of the common carotid artery was correlated with that of the ipsilateral internal carotid artery. The main error was attributed to the external carotid artery and its branches. Therefore,after selecting the appropriate scanning parameters and protocols, 2D PC MRA is more accuratein the determination of BFV in the carotid arteries.

  16. Immersive volume rendering of blood vessels

    Science.gov (United States)

    Long, Gregory; Kim, Han Suk; Marsden, Alison; Bazilevs, Yuri; Schulze, Jürgen P.

    2012-03-01

    In this paper, we present a novel method of visualizing flow in blood vessels. Our approach reads unstructured tetrahedral data, resamples it, and uses slice based 3D texture volume rendering. Due to the sparse structure of blood vessels, we utilize an octree to efficiently store the resampled data by discarding empty regions of the volume. We use animation to convey time series data, wireframe surface to give structure, and utilize the StarCAVE, a 3D virtual reality environment, to add a fully immersive element to the visualization. Our tool has great value in interdisciplinary work, helping scientists collaborate with clinicians, by improving the understanding of blood flow simulations. Full immersion in the flow field allows for a more intuitive understanding of the flow phenomena, and can be a great help to medical experts for treatment planning.

  17. Use of time attenuation curves to determine steady-state characteristics before C-arm CT measurement of cerebral blood volume

    Energy Technology Data Exchange (ETDEWEB)

    Caroff, Jildaz; Jittapiromsak, Pakrit; Benachour, Nidhal; Mihalea, Cristian; Rouchaud, Aymeric; Neki, Hiroaki; Ikka, Leon; Moret, Jacques; Spelle, Laurent [Beaujon Medical Center, NEURI - Interventional Neuroradiology, Paris Diderot University, Clichy (France); Ruijters, Daniel [Philips Healthcare, Interventional X-Ray Innovation, Best (Netherlands)

    2014-03-15

    Cerebral blood volume (CBV) measurement by flat panel detector CT (FPCT) in the angiography suite seems to be a promising tool for patient management during endovascular therapies. A steady state of contrast agent distribution is mandatory during acquisition for accurate FPCT CBV assessment. To the best of our knowledge, this was the first time that steady-state parameters were studied in clinical practice. Before the CBV study, test injections were performed and analyzed to determine a customized acquisition delay from injection for each patient. Injection protocol consisted in the administration of 72 mL of contrast agent material at the injection rate of 4.0 mL/s followed by a saline flush bolus at the same injection rate. Peripheral or central venous accesses were used depending on their availability. Twenty-four patients were treated for different types of neurovascular diseases. Maximal attenuation, steady-state length, and steady-state delay from injection were derived from the test injections' time attenuation curves. With a 15 % threshold from maximum attenuation values, average steady-state duration was less than 10 s. Maximum average steady-state duration with minimal delay variation was obtained with central injection protocols. With clinically acceptable contrast agent volumes, steady state is a brief condition; thus, fast rotation speed acquisitions are needed. The use of central injections decreases the variability of steady-state's delay from injection. Further studies are needed to optimize and standardize injection protocols to allow a larger diffusion of the FPCT CBV measurement during endovascular treatments. (orig.)

  18. Development of limb volume measuring system

    Science.gov (United States)

    Bhagat, P. K.; Kadaba, P. K.

    1983-01-01

    The mechanisms underlying the reductions in orthostatic tolerance associated with weightlessness are not well established. Contradictory results from measurements of leg volume changes suggest that altered venomotor tone and reduced blood flow may not be the only contributors to orthostatic intolerance. It is felt that a more accurate limb volume system which is insensitive to environmental factors will aid in better quantification of the hemodynamics of the leg. Of the varous limb volume techniques presently available, the ultrasonic limb volume system has proven to be the best choice. The system as described herein is free from environmental effects, safe, simple to operate and causes negligible radio frequency interference problems. The segmental ultrasonic ultrasonic plethysmograph is expected to provide a better measurement of limb volume change since it is based on cross-sectional area measurements.

  19. Altitude acclimatization and blood volume: effects of exogenous erythrocyte volume expansion

    DEFF Research Database (Denmark)

    Sawka, M N; Young, Jette Feveile; Rock, P B;

    1996-01-01

    We studied sea-level residents during 13 days of altitude acclimatization to determine 1) altitude acclimatization effects on erythrocyte volume and plasma volume, 2) if exogenous erythrocyte volume expansion alters subsequent erythrocyte volume and plasma volume adaptations, 3) if an increased...... blood oxygen content alters erythropoietin responses during altitude acclimatization, and 4) mechanisms responsible for plasma loss at altitude. Sixteen healthy men had a series of hematologic measurements made at sea level, on the first and ninth days of altitude (4,300 m) residence, and after...... had no effect; in addition, initially at altitude, blood oxygen content was 8% higher in erythrocyte-infused than in saline-infused subjects. The new findings regarding altitude acclimatization are summarized as follows: 1) erythrocyte volume does not change during the first 13 days...

  20. [Development of ultrasound-based monitor of relative blood volume].

    Science.gov (United States)

    Jiang, Shunzhong; Hu, Xiao; Liang, Zhongwei; Fan, Jianghong; Xia, Wubing; Zhou, Hongbo; Yi, Wei

    2013-12-01

    Assessing dry weight accurately is crucial in providing effective and safe haemodialysis. Biases towards dry weight assessment may bring a series of dialysis complications. This study introduces an online detection technique of relative blood volume (RBV) based on ultrasound, which analyzes the correlation between changes in blood density and sound speed. By measuring the attenuation in sound velocity, this method was employed to calculate RBV, and then to evaluate the dry weight of patients on dialysis. TDC-GP2 time measurement chip and MSP430 Single-chip Microcontroller (SCM) were used in the system to measure the ultrasonic travel time. In the clinical trials, RBV values range between 71.3% and 108.1%, showing consistent result with Fresenius 4008S blood volume monitor (BVM). This detection method possesses several advantages, such as real time, convenient, reproducible, non-invasive, and etc.

  1. Measurement of the absolute optical properties and cerebral blood volume of the adult human head with hybrid differential and spatially resolved spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Terence S [Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT (United Kingdom); Tachtsidis, Ilias [Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT (United Kingdom); Smith, Martin [Department of Neuroanaesthesia and Neurocritical Care, The National Hospital for Neurology and Neurosurgery, London (United Kingdom); Delpy, David T [Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT (United Kingdom); Elwell, Clare E [Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2006-02-07

    A hybrid differential and spatially resolved spectroscopy (SRS) technique has been developed to measure absolute absorption coefficient ({mu}{sub a}), reduced scattering coefficient ({mu}'{sub s}) and cerebral blood volume (CBV) in the adult human head. A spectrometer with both differential and SRS capabilities has been used to carry out measurements in 12 subjects. Two versions of the calculation have been considered using the hybrid technique, with one considering water as a chromophore as well as oxy- and deoxy-haemoglobin, and one ignoring water. The CBV has also been measured using a previously described technique based on changing the arterial saturation (SaO{sub 2}) measured separately by a pulse oximeter, resulting in mean {+-} SD CBV{sup a} (intra-individual coefficient of variation) = 2.22 {+-} 1.06 ml/100 g (29.9%). (The superscript on CBV indicates the different calculation basis.) Using the hybrid technique with water ignored, CBV{sup 0} = 3.18 {+-} 0.73 ml/100 g (10.0%), {mu}{sup 0}{sub a}(813 nm) = 0.010 {+-} 0.003 mm{sup -1} and {mu}'{sup 0}{sub s}(813 nm) = 1.19 {+-} 0.55 mm{sup -1} (data quoted at 813 nm). With water considered, CBV{sup w} = 3.05 {+-} 0.77 ml/100 g (10.5%), {mu}{sup w}{sub a}(813 nm) = 0.010 {+-} 0.003 mm{sup -1} and {mu}'{sup w}{sub s}(813 nm) = 1.28 {+-} 0.56 mm{sup -1}. The mean biases between CBV{sup 0}/CBV{sup w}, CBV{sup 0}/CBV{sup a} and CBV{sup w}/CBV{sup a} are 0.14 {+-} 0.09, 0.79 {+-} 1.22 and 0.65 {+-} 1.24 ml/100 g. The mean biases between {mu}{sup 0}{sub a}(813 nm)/{mu}{sup w}{sub a}(813 nm) and {mu}'{sup 0}{sub s}(813 nm)/{mu}'{sup w}{sub s}(813 nm) are (5.9 {+-} 10.0) x 10{sup -4} mm{sup -1} and -0.084 {+-} 0.266 mm{sup -1}, respectively. The method we describe extends the functionality of the current SRS instrumentation.

  2. Cosmological Measures without Volume Weighting

    CERN Document Server

    Page, Don N

    2008-01-01

    Many cosmologists (myself included) have advocated volume weighting for the cosmological measure problem, weighting spatial hypersurfaces by their volume. However, this often leads to the Boltzmann brain problem, that almost all observations would be by momentary Boltzmann brains that arise very briefly as quantum fluctuations in the late universe when it has expanded to a huge size, so that our observations (too ordered for Boltzmann brains) would be highly atypical and unlikely. Here it is suggested that volume weighting may be a mistake. Volume averaging is advocated as an alternative. One consequence would be a loss of the argument for eternal inflation.

  3. Non-Invasive Optical Blood Glucose Measurement

    Directory of Open Access Journals (Sweden)

    Megha C.Pande

    2013-07-01

    Full Text Available The method for noninvasively blood glucose monitoring system is discussed in this paper. Lot of research work has been done in developing the device which is completely noninvasive to avoid the pros & cons because of frequent pricking. In this paper we are trying to analyze the noninvasive blood glucose measurement study in the near infrared region which is the most suitable region for blood glucose measurement. For this purpose we use a technique which is similar to pulseoximetry based on near infrared spectrometry .An infrared light of particular wavelength is passed through fingertip containing an arterial pulse component are derived,thus minimizing influences of basal components such as resting blood volume,skin, muscle and bone.

  4. VOLUMNECT: measuring volumes with Kinect

    Science.gov (United States)

    Quintino Ferreira, Beatriz; Griné, Miguel; Gameiro, Duarte; Costeira, João. Paulo; Sousa Santos, Beatriz

    2014-03-01

    This article presents a solution to volume measurement object packing using 3D cameras (such as the Microsoft KinectTM). We target application scenarios, such as warehouses or distribution and logistics companies, where it is important to promptly compute package volumes, yet high accuracy is not pivotal. Our application auto- matically detects cuboid objects using the depth camera data and computes their volume and sorting it allowing space optimization. The proposed methodology applies to a point cloud simple computer vision and image processing methods, as connected components, morphological operations and Harris corner detector, producing encouraging results, namely an accuracy in volume measurement of 8mm. Aspects that can be further improved are identified; nevertheless, the current solution is already promising turning out to be cost effective for the envisaged scenarios.

  5. Volumetric measurement of tank volume

    Science.gov (United States)

    Walter, Richard T. (Inventor); Vanbuskirk, Paul D. (Inventor); Weber, William F. (Inventor); Froebel, Richard C. (Inventor)

    1991-01-01

    A method is disclosed for determining the volume of compressible gas in a system including incompressible substances in a zero-gravity environment consisting of measuring the change in pressure (delta P) for a known volume change rate (delta V/delta t) in the polytrophic region between isothermal and adiabatic conditions. The measurements are utilized in an idealized formula for determining the change in isothermal pressure (delta P sub iso) for the gas. From the isothermal pressure change (delta iso) the gas volume is obtained. The method is also applicable to determination of gas volume by utilizing work (W) in the compression process. In a passive system, the relationship of specific densities can be obtained.

  6. 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.

  7. Effect of volume expansion on systemic hemodynamics and central and arterial blood volume in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Bendtsen, Flemming; Henriksen, Jens Henrik

    1995-01-01

    and in controls. METHODS: Thirty-nine patients with cirrhosis (12 patients with Child-Turcotte class A, 14 with class B, and 13 with class C) and 6 controls were studied. During hepatic vein catheterization, cardiac output, systemic vascular resistance, central and arterial blood volume, noncentral blood volume...... in patients with either class B or class C. Conversely, the noncentral blood volume increased in patients with class B and C. In both patients and controls, the cardiac output increased and the systemic vascular resistance decreased, whereas the mean arterial blood pressure did not change significantly......BACKGROUND & AIMS: Systemic vasodilatation in cirrhosis may lead to hemodynamic alterations with reduced effective blood volume and decreased arterial blood pressure. This study investigates the response of acute volume expansion on hemodynamics and regional blood volumes in patients with cirrhosis...

  8. Membrane diffusion- and capillary blood volume measurements are not useful as screening tools for pulmonary arterial hypertension in systemic sclerosis: a case control study

    Directory of Open Access Journals (Sweden)

    Spreeuwenberg Marieke D

    2008-10-01

    Full Text Available Abstract Background There is no optimal screening tool for the assessment of pulmonary arterial hypertension (PAH in patients with systemic sclerosis (SSc. A decreasing transfer factor of the lung for CO (TLCO is associated with the development of PAH in SSc. TLCO can be partitioned into the diffusion of the alveolar capillary membrane (Dm and the capillary blood volume (Vc. The use of the partitioned diffusion to detect PAH in SSc is not well established yet. This study evaluates whether Dm and Vc could be candidates for further study of the use for screening for PAH in SSc. Methods Eleven SSc patients with PAH (SScPAH+, 13 SSc patients without PAH (SScPAH- and 10 healthy control subjects were included. Pulmonary function testing took place at diagnosis of PAH. TLCO was partitioned according to Roughton and Forster. As pulmonary fibrosis in SSc influences values of the (partitioned TLCO, these were adjusted for fibrosis score as assessed on HRCT. Results TLCO as percentage of predicted (% was lower in SScPAH+ than in SScPAH- (41 ± 7% vs. 63 ± 12%, p vs. 39 ± 12%, p Conclusion SScPAH+ patients have lower Dm% than SScPAH- patients. There are no correlations between Dm% and hemodynamic parameters of PAH in SScPAH+. These findings do not support further study of the role of partitioning TLCO in the diagnostic work- up for PAH in SSc.

  9. Resistance exercise with different volumes: blood pressure response and forearm blood flow in the hypertensive elderly

    Science.gov (United States)

    Brito, Aline de Freitas; de Oliveira, Caio Victor Coutinho; Brasileiro-Santos, Maria do Socorro; Santos, Amilton da Cruz

    2014-01-01

    Background The purpose of this study was to evaluate the effect of two sessions of resistance exercise with different volumes on post-exercise hypotension, forearm blood flow, and forearm vascular resistance in hypertensive elderly subjects. Methods The study was conducted with ten hypertensive elderly (65±3 years, 28.7±3 kg/m2) subjected to three experimental sessions, ie, a control session, exercise with a set (S1), and exercise with three sets (S3). For each session, the subjects were evaluated before and after intervention. In the pre-intervention period, blood pressure, forearm blood flow, and forearm vascular resistance were measured after 10 minutes of rest in the supine position. Thereafter, the subjects were taken to the gym to perform their exercise sessions or remained at rest during the same time period. Both S1 and S3 comprised a set of ten repetitions of ten exercises, with an interval of 90 seconds between exercises. Subsequently, the measurements were again performed at 10, 30, 50, 70, and 90 minutes of recovery (post-intervention) in the supine position. Results Post-exercise hypotension was greater in S3 than in S1 (systolic blood pressure, −26.5±4.2 mmHg versus −17.9±4.7 mmHg; diastolic blood pressure, −13.8±4.9 mmHg versus −7.7±5 mmHg, P<0.05). Similarly, forearm blood flow and forearm vascular resistance changed significantly in both sessions with an increase and decrease, respectively, that was more evident in S3 than in S1 (P<0.05). Conclusion Resistance exercises with higher volume were more effective in causing post-exercise hypotension, being accompanied by an increase in forearm blood flow and a reduction of forearm vascular resistance. PMID:25540580

  10. Relationship between stroke volume and pulse pressure during blood volume perturbation: a mathematical analysis.

    Science.gov (United States)

    Bighamian, Ramin; Hahn, Jin-Oh

    2014-01-01

    Arterial pulse pressure has been widely used as surrogate of stroke volume, for example, in the guidance of fluid therapy. However, recent experimental investigations suggest that arterial pulse pressure is not linearly proportional to stroke volume. However, mechanisms underlying the relation between the two have not been clearly understood. The goal of this study was to elucidate how arterial pulse pressure and stroke volume respond to a perturbation in the left ventricular blood volume based on a systematic mathematical analysis. Both our mathematical analysis and experimental data showed that the relative change in arterial pulse pressure due to a left ventricular blood volume perturbation was consistently smaller than the corresponding relative change in stroke volume, due to the nonlinear left ventricular pressure-volume relation during diastole that reduces the sensitivity of arterial pulse pressure to perturbations in the left ventricular blood volume. Therefore, arterial pulse pressure must be used with care when used as surrogate of stroke volume in guiding fluid therapy.

  11. Measurement of blood flow volume and its characteristic in the shunt after TIPS with intravascular Doppler guidewire%多普勒导丝评价TIPS术门腔分流道血流特点

    Institute of Scientific and Technical Information of China (English)

    徐晤; 祖茂衡; 王志荣; 李国均

    2012-01-01

    Objective Via the measurement of blood flow volume after TIPS (transjugular intrahepatic portosystemic shunt) with intravascular Doppler guidewire, a novel, reliable method to investigate the hemodynamical parameters of TIPS was tested. Methods With Doppler guidewire. blood flow velocity in the TIPS of 10 patients with portal hypertension were measured, and with the aid of DSA, blood flow volume was obtained. 10 normal hepatic veins were taken as contral. Results After TIPS,some parameters in the TIPS were gained: Average Peak Velocity (APV) was (18. 51± 7. 32) cm/s, Maximum Peak Velocity (MPV) was (25. 93±9. 54) cm/s, blood flow volumes were (557. 95 + 94. 57) ml/ min; and blood flow spectrum was acquired. The wave was nomo-phase in pattern and dischanged with the heart cycle. At the same time, the parameters in hepatic veins were as follows; APV was (15. 73±4. 52) cm/s;MPV was (26. 01±8. 33) cm/s;blood flow volume was (654. 64± 108. 56) ml/min. The wave was three-phase in pattern and changed with the heart cycle. Conclusion Accurately and conveniently, blood flow velocity in the TIPS was measured by intravascular Doppler guidewire. The present work on the TIPS in patients illustrated that the novel method is practicable and reliable for measuring the blood flow,%目的 应用血管内多普勒导丝测定TIPS术后门腔分流量及血流特点,提出一种新的、更可靠的检测静脉血流动力学指标的方法.方法 10例门静脉高压患者TIPS术后即刻,使用血管内多普勒导丝测定分流通道内血流速度,结合DSA技术,测出血流量;并予10例正常肝静脉血流作为对照.结果 测得TIPS术后分流通道内的平均峰值流速(APV)为(18.51±7.32)cm/s,最大峰值流速(MPV)为(25.93±9,54)cm/s,分流道的直径为(0.80±0.26)cm,门腔分流量为(557.96±94.57)ml/min,并且获得血流频谱特点为波形呈单相,不随心动周期而变化.而肝静脉APV为(15.73±4.52)cm/s;MPV为(26.01±8.33)cm

  12. Effect of volume expansion on systemic hemodynamics and central and arterial blood volume in cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Bendtsen, F; Henriksen, Jens Henrik Sahl

    1995-01-01

    and in controls. METHODS: Thirty-nine patients with cirrhosis (12 patients with Child-Turcotte class A, 14 with class B, and 13 with class C) and 6 controls were studied. During hepatic vein catheterization, cardiac output, systemic vascular resistance, central and arterial blood volume, noncentral blood volume...

  13. Measurements of diagnostic examination performance and correlation analysis using microvascular leakage, cerebral blood volume, and blood flow derived from 3T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in glial tumor grading

    Energy Technology Data Exchange (ETDEWEB)

    Server, Andres; Nakstad, Per H. [Oslo University Hospital-Ullevaal, Section of Neuroradiology, Department of Radiology and Nuclear Medicine, Oslo (Norway); University of Oslo, Oslo (Norway); Graff, Bjoern A. [Oslo University Hospital-Ullevaal, Department of Radiology and Nuclear Medicine, Oslo (Norway); Orheim, Tone E.D.; Gadmar, Oeystein B. [Oslo University Hospital, Interventional Centre, Oslo (Norway); Schellhorn, Till [Oslo University Hospital-Ullevaal, Section of Neuroradiology, Department of Radiology and Nuclear Medicine, Oslo (Norway); Josefsen, Roger [Oslo University Hospital-Ullevaal, Department of Neurosurgery, Oslo (Norway)

    2011-06-15

    To assess the diagnostic accuracy of microvascular leakage (MVL), cerebral blood volume (CBV) and blood flow (CBF) values derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC-MR imaging) for grading of cerebral glial tumors, and to estimate the correlation between vascular permeability/perfusion parameters and tumor grades. A prospective study of 79 patients with cerebral glial tumors underwent DSC-MR imaging. Normalized relative CBV (rCBV) and relative CBF (rCBF) from tumoral (rCBVt and rCBFt), peri-enhancing region (rCBVe and rCBFe), and the value in the tumor divided by the value in the peri-enhancing region (rCBVt/e and rCBFt/e), as well as MVL, expressed as the leakage coefficient K{sub 2} were calculated. Hemodynamic variables and tumor grades were analyzed statistically and with Pearson correlations. Receiver operating characteristic (ROC) curve analyses were also performed for each of the variables. The differences in rCBVt and the maximum MVL (MVL{sub max}) values were statistically significant among all tumor grades. Correlation analysis using Pearson was as follows: rCBVt and tumor grade, r = 0.774; rCBFt and tumor grade, r = 0.417; MVL{sub max} and tumor grade, r = 0.559; MVL{sub max} and rCBVt, r = 0.440; MVL{sub max} and rCBFt, r = 0.192; and rCBVt and rCBFt, r = 0.605. According to ROC analyses for distinguishing tumor grade, rCBVt showed the largest areas under ROC curve (AUC), except for grade III from IV. Both rCBVt and MVL{sub max} showed good discriminative power in distinguishing all tumor grades. rCBVt correlated strongly with tumor grade; the correlation between MVL{sub max} and tumor grade was moderate. (orig.)

  14. Resistance exercise with different volumes: blood pressure response and forearm blood flow in the hypertensive elderly

    Directory of Open Access Journals (Sweden)

    Brito AF

    2014-12-01

    Full Text Available Aline de Freitas Brito,1 Caio Victor Coutinho de Oliveira,2 Maria do Socorro Brasileiro-Santos,1 Amilton da Cruz Santos1 1Physical Education Department, 2Research Laboratory for Physical Training Applied to Performance and Health, Federal University of Paraíba, João Pessoa, Brazil Background: The purpose of this study was to evaluate the effect of two sessions of resistance exercise with different volumes on post-exercise hypotension, forearm blood flow, and forearm vascular resistance in hypertensive elderly subjects.Methods: The study was conducted with ten hypertensive elderly (65±3 years, 28.7±3 kg/m2 subjected to three experimental sessions, ie, a control session, exercise with a set (S1, and exercise with three sets (S3. For each session, the subjects were evaluated before and after intervention. In the pre-intervention period, blood pressure, forearm blood flow, and forearm vascular resistance were measured after 10 minutes of rest in the supine position. Thereafter, the subjects were taken to the gym to perform their exercise sessions or remained at rest during the same time period. Both S1 and S3 comprised a set of ten repetitions of ten exercises, with an interval of 90 seconds between exercises. Subsequently, the measurements were again performed at 10, 30, 50, 70, and 90 minutes of recovery (post-intervention in the supine position.Results: Post-exercise hypotension was greater in S3 than in S1 (systolic blood pressure, −26.5±4.2 mmHg versus −17.9±4.7 mmHg; diastolic blood pressure, −13.8±4.9 mmHg versus −7.7±5 mmHg, P<0.05. Similarly, forearm blood flow and forearm vascular resistance changed significantly in both sessions with an increase and decrease, respectively, that was more evident in S3 than in S1 (P<0.05.Conclusion: Resistance exercises with higher volume were more effective in causing post-exercise hypotension, being accompanied by an increase in forearm blood flow and a reduction of forearm vascular

  15. Measuring blood oxygenation of pulsatile arteries using photoacoustic microscopy

    Science.gov (United States)

    Li, Qian; Yu, Tianhao; Li, Lin; Chai, Xinyu; Zhou, Chuanqing

    2016-10-01

    Heart pumps blood through the blood vessels to provide body with oxygen and nutrients. As the result, the blood flow, volume and oxygenation in arteries has a pulsatile nature. Measuring these pulsatile parameters enables more precise monitoring of oxygen metabolic rate and is thus valuable for researches and clinical applications. Photoacoustic microscopy (PAM) is a proven label-free method for in vivo measuring blood oxygenation at single blood vessel level. However, studies using PAM to observe the pulsatile nature of blood oxygenation in arteries were not reported. In this paper, we use optical-resolution PAM (OR-PAM) technology to study the blood oxygenation dynamics of pulsatile arteries. First, the ability of our OR-PAM system to accurately reflect the change of optical absorption in imaged objects is demonstrated in a phantom study. Then the system is used to image exposed cortical blood vessels of cat. The pulsatile nature of blood volume and oxygenation in arteries is clearly reflected in photoacoustic (PA) signals, whereas it's not observable in veins. By using a multi-wavelength laser, the dynamics of the blood oxygenation of pulsatile arteries in cardiac cycles can be measured, based on the spectroscopic method.

  16. Oxygenation and Blood Volume Periodic Waveforms in the Brain

    CERN Document Server

    Gersten, Alexander; Raz, Amir

    2011-01-01

    Results of an experiment are presented whose aim is to explore the relationship between respiration and cerebral oxygenation. Measurements of end tidal CO2 (EtCO2) were taken simultaneously with cerebral oxygen saturation (rSO2) using the INVOS Cerebral Oximeter of Somanetics. Due to the device limitations we could explore only subjects who could perform with a breathing rate of around 2/min or less. Six subjects were used who were experienced in yoga breathing techniques. They performed an identical periodic breathing exercise including periodicity of about 2/min. The results of all six subjects clearly show a periodic change of cerebral oxygenation with the same period as the breathing exercises. Similar periodic changes in blood volume index were observed as well.

  17. Do intravascular hypo- and hypervolaemia result in changes in central blood volumes?

    NARCIS (Netherlands)

    Vos, J. J.; Scheeren, T. W. L.; Loer, S. A.; Hoeft, A.; Wietasch, J. K. G.

    2016-01-01

    Background: Hypovolaemia is generally believed to induce centralization of blood volume. Therefore, we evaluated whether induced hypo-and hypervolaemia result in changes in central blood volumes (pulmonary blood volume (PBV), intrathoracic blood volume (ITBV)) and we explored the effects on the dist

  18. Single-cell measurement of red blood cell oxygen affinity

    CERN Document Server

    Caprio, Di; Higgins, John M; Schonbrun, Ethan

    2015-01-01

    Oxygen is transported throughout the body by hemoglobin in red blood cells. While the oxygen affinity of blood is well understood and is routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of red blood cell volume and hemoglobin concentration are taken millions of times per day by clinical hematology analyzers and are important factors in determining the health of the hematologic system. To better understand the variability and determinants of oxygen affinity on a cellular level, we have developed a system that quantifies the oxygen saturation, cell volume and hemoglobin concentration for individual red blood cells in high-throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.5%, which corresponds to the maximum slope of the oxygen-hemoglobin dissociation curve. In addition, single-cell oxygen affinity is positively correlated with hemoglobin concentr...

  19. Blood Volume Response to Physical Activity and Inactivity

    Science.gov (United States)

    2007-07-01

    total vascular capacitance,4 so central venous pres- sure (CVP) becomes elevated. Although elevated CVP usually stimulates diuresis and prevents volume...stimulating a feedback diuresis . Thus, the mechanisms underlying the increased blood volume that accompanies physical activity in- clude increased thirst...vasopressin are acutely decreased.23 These endocrine responses are accom- panied by an acute increase in total urine and so- dium excretion ( diuresis and

  20. C-arm flat detector computed tomography parenchymal blood volume imaging: the nature of parenchymal blood volume parameter and the feasibility of parenchymal blood volume imaging in aneurysmal subarachnoid haemorrhage patients

    Energy Technology Data Exchange (ETDEWEB)

    Kamran, Mudassar; Byrne, James V. [University of Oxford, Nuffield Department of Surgical Sciences, Oxford (United Kingdom)

    2015-09-15

    C-arm flat detector computed tomography (FDCT) parenchymal blood volume (PBV) measurements allow assessment of cerebral haemodynamics in the neurointerventional suite. This paper explores the feasibility of C-arm computed tomography (CT) PBV imaging and the relationship between the C-arm CT PBV and the MR-PWI-derived cerebral blood volume (CBV) and cerebral blood flow (CBF) parameters in aneurysmal subarachnoid haemorrhage (SAH) patients developing delayed cerebral ischemia (DCI). Twenty-six patients with DCI following aneurysmal SAH underwent a research C-arm CT PBV scan using a biplane angiography system and contemporaneous MR-PWI scan as part of a prospective study. Quantitative whole-brain atlas-based volume-of-interest analysis in conjunction with Pearson correlation and Bland-Altman tests was performed to explore the agreement between C-arm CT PBV and MR-derived CBV and CBF measurements. All patients received medical management, while eight patients (31 %) underwent selective intra-arterial chemical angioplasty. Colour-coded C-arm CT PBV maps were 91 % sensitive and 100 % specific in detecting the perfusion abnormalities. C-arm CT rPBV demonstrated good agreement and strong correlation with both MR-rCBV and MR-rCBF measurements; the agreement and correlation were stronger for MR-rCBF relative to MR-rCBV and improved for C-arm CT PBV versus the geometric mean of MR-rCBV and MR-rCBF. Analysis of weighted means showed that the C-arm CT PBV has a preferential blood flow weighting (∼60 % blood flow and ∼40 % blood volume weighting). C-arm CT PBV imaging is feasible in DCI following aneurysmal SAH. PBV is a composite perfusion parameter incorporating both blood flow and blood volume weightings. That PBV has preferential (∼60 %) blood flow weighting is an important finding, which is of clinical significance when interpreting the C-arm CT PBV maps, particularly in the setting of acute brain ischemia. (orig.)

  1. Estimation of Relative Blood Volume in Head and Neck Tumors

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Introduction: The calculation of relative blood volume in head and neck tumor with MR imaging is anew approach that may provide additional hemodynamic information relevant to both untreated and treated tumors. This hemodynamic information is especially usefu l for the differentiation between viable tumor and postsurgical changes or rad iation induced scar, and is also beneficial for tumor staging and tumor biopsy.

  2. 21 CFR 862.1130 - Blood volume test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Blood volume test system. 862.1130 Section 862.1130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  3. Hemodynamic and ADH responses to central blood volume shifts in cardiac-denervated humans

    Science.gov (United States)

    Convertino, V. A.; Thompson, C. A.; Benjamin, B. A.; Keil, L. C.; Savin, W. M.; Gordon, E. P.; Haskell, W. L.; Schroeder, J. S.; Sandler, H.

    1990-01-01

    Hemodynamic responses and antidiuretic hormone (ADH) were measured during body position changes designed to induce blood volume shifts in ten cardiac transplant recipients to assess the contribution of cardiac and vascular volume receptors in the control of ADH secretion. Each subject underwent 15 min of a control period in the seated posture, then assumed a lying posture for 30 min at 6 deg head down tilt (HDT) followed by 20 min of seated recovery. Venous blood samples and cardiac dimensions (echocardiography) were taken at 0 and 15 min before HDT, 5, 15, and 30 min of HDT, and 5, 15, and 30 min of seated recovery. Blood samples were analyzed for hematocrit, plasma osmolality, plasma renin activity (PRA), and ADH. Resting plasma volume (PV) was measured by Evans blue dye and percent changes in PV during posture changes were calculated from changes in hematocrit. Heart rate (HR) and blood pressure (BP) were recorded every 2 min. Results indicate that cardiac volume receptors are not the only mechanism for the control of ADH release during acute blood volume shifts in man.

  4. Methods for blood flow measurements using ultrasound contrast agents

    Science.gov (United States)

    Fowlkes, J. Brian

    2003-10-01

    Blood flow measurements using ultrasound contrast agents are being investigated for myocardial perfusion and more recently in other organ systems. The methods are based largely on the relative increase in echogenicity due to the concentration of bubbles present in the ultrasound beam. In the simplest form, regional differences in blood volume can be inferred but the possibility exists to extract perfusion from the transit of contrast agent through tissue. Perfusion measurements rely on determining the flux of blood through a tissue volume and as such require knowledge of the fractional blood volume (FBV), i.e., ml blood/g tissue and the rate of exchange, commonly measured as the mean transit time (MTT). This presentation will discuss methods of determining each of these values and their combination to estimate tissue perfusion. Underlying principles of indicator-dilution theory will be provided in the context of ultrasound contrast agents. Current methods for determining MTT will include imaging of the intravenous bolus, in-plane contrast disruption with interval and real-time contrast recovery imaging, and control of contrast agent flow using arterial disruption (contrast interruption). The advantages and limitations of the methods will be examined along with current applications. [Work supported in part by NIH.

  5. Determination of micro-litre volumes with high accuracy for flow cytometric blood cell counting

    Science.gov (United States)

    Reitz, S.; Kummrow, A.; Kammel, M.; Neukammer, J.

    2010-07-01

    We have gravimetrically calibrated the volumes dispensed by 1 mL syringes in the range between 1 µL and 100 µL using ultra-pure water. Protocols are based on series of consecutive difference measurements of masses in order to precisely compensate for evaporation, being the most important disturbing quantity. We determined expanded uncertainties of volume measurements for glass syringes of typically 0.2% (expansion factor 2) when dispensing volumes of 10 µL. For polypropylene syringes, selected with respect to the manufacturer, expanded uncertainties of 0.25% (expansion factor 2) were observed. Calibrated syringes were applied for measuring concentrations of blood cells in a flow cytometer demonstrating the capability to determine reference measurement values. Since the direct interaction of blood cells and syringe walls may lead to cell adhesion, glass syringes as well as (disposable) polypropylene syringes were calibrated.

  6. Pancreatic islet blood flow and its measurement.

    Science.gov (United States)

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-05-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future.

  7. Measured and Calculated Volumes of Wetland Depressions

    Data.gov (United States)

    U.S. Environmental Protection Agency — Measured and calculated volumes of wetland depressions This dataset is associated with the following publication: Wu, Q., and C. Lane. Delineation and quantification...

  8. Effect of Local Temperature on the Detecting for Pulse Wave of Local Blood Volume

    Directory of Open Access Journals (Sweden)

    Tingting Yan

    2013-07-01

    Full Text Available [Objective] Temperature of a subject's external body parts is an interference condition in pulse wave of local blood volume measurement. It is necessary to rule it out. By changing the influence factors, an experiment to research the effect of temperature of subjected part in pulse wave of local blood volume measurement was carried out. [Methods] When the 32 experimenters' left middle finger temperature fall below to 20°C, pulse wave of local blood volume would be recorded detected in real-time until the temperature returned to the measured values before the experiment [Results] While the temperature of subjected part ranged from 26°C to 31°C, the parameters of K', K1', K2' and the amplitude of pulse wave remain basically unchanged. [Conclusion] As a result of the research data, it is stipulated that the pulse wave of local blood volume can be measured only if the finger temperature is in the range of 26-31°C.

  9. Quantitative Cerebral Blood Flow Measurements Using MRI

    OpenAIRE

    Muir, Eric R; Watts, Lora Talley; Tiwari, Yash Vardhan; Bresnen, Andrew; Timothy Q Duong

    2014-01-01

    Magnetic resonance imaging utilized as a quantitative and noninvasive method to image cerebral blood flow. The two most common techniques used to detect cerebral blood flow are dynamic susceptibility contrast (DSC) perfusion MRI and arterial spin labeling perfusion MRI. Herein we describe the use of these two techniques to measure cerebral blood flow in rodents, including methods, analysis, and important considerations when utilizing these techniques.

  10. Finger temperature controller for non-invasive blood glucose measurement

    Science.gov (United States)

    Zhang, Xiqin; Ting, Choon Meng; Yeo, Joon Hock

    2010-11-01

    Blood glucose level is an important parameter for doctors to diagnose and treat diabetes. The Near-Infra-Red (NIR) spectroscopy method is the most promising approach and this involves measurement on the body skin. However it is noted that the skin temperature does fluctuate with the environmental and physiological conditions and we found that temperature has important influences on the glucose measurement. In-vitro and in-vivo investigations on the temperature influence on blood glucose measurement have been carried out. The in-vitro results show that water temperature has significant influence on water absorption. Since 90% of blood components are water, skin temperature of measurement site has significant influence on blood glucose measurement. Also the skin temperature is related to the blood volume, blood volume inside capillary vessels changes with skin temperature. In this paper the relationship of skin temperature and signal from the skin and inside tissue was studied at different finger temperatures. Our OGTT (oral glucose tolerance test) trials results show the laser signals follow the skin temperature trend and the correlation of signal and skin temperature is much stronger than the correlation of signal and glucose concentration. A finger heater device is designed to heat and maintain the skin temperature of measurement site. The heater is controlled by an electronic circuit according to the skin temperature sensed by a thermocouple that is put close to the measurement site. In vivo trials were carried out and the results show that the skin temperature significantly influences the signal fluctuations caused by pulsate blood and the average signal value.

  11. Kidney volume and ambulatory blood pressure in children.

    Science.gov (United States)

    Gurusinghe, Shari; Palvanov, Arkadiy; Bittman, Mark E; Singer, Pamela; Frank, Rachel; Chorny, Nataliya; Infante, Lulette; Sethna, Christine B

    2016-12-16

    Low nephron number has been shown to be a risk factor for hypertension (HTN) in adulthood. Kidney volume may serve as a surrogate marker for nephron mass. The relationship between kidney volume and ambulatory blood pressure (BP) in the pediatric population is not known. A retrospective chart review of children younger than 21 years who were evaluated for HTN was performed. Twenty-four-hour BP and ultrasonography data were obtained. Multiple regression was used to examine associations between BP and kidney volume. Of 84 children (mean age 13.87 years, 72.6% males), 54 had HTN. Systolic BP index during the awake, sleep, and 24-hour periods (all P≤.05) was found to be positively correlated with total kidney volume. Greater total kidney volume was found to be a positive predictor of 24-hour and sleep systolic index (P≤.05). It failed to serve as a predictor of HTN, pre-HTN, or white-coat HTN. Contrary to expectation, total kidney volume was positively associated with systolic BP indices.

  12. Working meeting on blood pressure measurement: suggestions for measuring blood pressure to use in populations surveys.

    Science.gov (United States)

    2003-11-01

    As part of the Pan American Hypertension Initiative (PAHI), the Pan American Health Organization and the National Heart, Lung, and Blood Institute of the National Institutes of Health of the United States of America conducted a working meeting to discuss blood pressure (BP) measurement methods used in various hypertension prevalence surveys and clinical trials, with the objective of developing a BP measurement protocol for use in hypertension prevalence surveys in the Americas. No such common protocol has existed in the Americas, so it has been difficult to compare hypertension prevention and intervention strategies. This piece describes a proposed standard method for measuring blood pressure for use in population surveys in the Region of the Americas. The piece covers: considerations for developing a common blood pressure measurement protocol, critical issues in measuring blood pressure in national surveys, minimum procedures for blood pressure measurement during surveillance, and quality assessment of blood pressure.

  13. Colloid volume loading does not mitigate decreases in central blood volume during simulated hemorrhage while heat stressed

    DEFF Research Database (Denmark)

    Crandall, Craig G; Wilson, Thad E; Marving, Jens;

    2012-01-01

    attenuates the reduction in regional blood volumes during a simulated hemorrhagic challenge imposed via lower-body negative pressure (LBNP). Seven subjects underwent 30 mmHg LBNP while normothermic, during passive heat stress (increased internal temperature ~1°C), and while continuing to be heated after...... intravenous colloid volume loading (11 ml/kg). Relative changes in torso and regional blood volumes were determined by gamma camera imaging with technetium-99m labeled erythrocytes. Heat stress reduced blood volume in all regions (ranging from 7 to 16%), while subsequent volume loading returned those values...... to normothermic levels. While normothermic, LBNP reduced blood volume in all regions (torso: 22±8%; heart: 18±6%; spleen: 15±8%). During LBNP while heat stressed, the reductions in blood volume in each region were markedly greater when compared to LBNP while normothermic (torso: 73±2%; heart: 72±3%; spleen: 72...

  14. Erythrocytes labeled with [(18) F]SFB as an alternative to radioactive CO for quantification of blood volume with PET.

    Science.gov (United States)

    Herance, José Raúl; Gispert, Juan Domingo; Abad, Sergio; Victor, Victor M; Pareto, Deborah; Torrent, Èlia; Rojas, Santiago

    2013-01-01

    Inhaled radioactive CO is currently the tracer of choice for blood volume quantification by positron emission tomography (PET). This measurement is of great interest for several clinical and research applications. However, owing to the short half-life of the radiolabeled CO, it can only be used in centers equipped with a cyclotron. In the present work, we propose an alternative method to label the red blood cells with [(18) F] in order to obtain blood volume measurements by PET. The use of the radioactive synthon [(18) F] N-succinimidyl 4-[(18) F]fluorobenzoate ([(18) F]SFB) was evaluated for erythrocyte labeling and PET blood volume imaging. The images provided by [(18) F]SFB labeled erythrocytes were compared with those obtained with inhaled [(11) C]CO. Blood volumes obtained with [(18) F]SFB labeled erythrocytes were similar to those obtained with [(11) C]CO in all of the evaluated organs with the exception of spleen, which presented lower uptake with this method. Since the [(18) F]-SFB binds irreversibly to red blood cells, in vivo stability of the radiolabel was higher compared with the [(11) C]CO method. Additionally, owing to the longer half-life and the shorter positron range of [(18) F], the image quality was also higher with the [(18) F]SFB radiolabeled erythrocytes. The labeling of red blood with [(18) F]SFB represents an advantageous alternative to radioactive CO for blood volume measurement by PET and cardiovascular isotopic imaging.

  15. Blood Glucose Measurement Using Bioimpedance Technique

    OpenAIRE

    2014-01-01

    Bioimpedance measurement is gaining importance in wide field of bioresearch and biomedical systems due to its noninvasive nature. Noninvasive measurement method is very important to decrease infection and physical injuries which result due to invasive measurement. This paper presents basic principle of bioimpedance along with its application for blood glucose analysis and effect of frequency on impedance measurement. Input from bioimpedance sensor is given to amplifier and signal conditioner ...

  16. Chronic fatigue syndrome: illness severity, sedentary lifestyle, blood volume and evidence of diminished cardiac function.

    Science.gov (United States)

    Hurwitz, Barry E; Coryell, Virginia T; Parker, Meela; Martin, Pedro; Laperriere, Arthur; Klimas, Nancy G; Sfakianakis, George N; Bilsker, Martin S

    2009-10-19

    The study examined whether deficits in cardiac output and blood volume in a CFS (chronic fatigue syndrome) cohort were present and linked to illness severity and sedentary lifestyle. Follow-up analyses assessed whether differences in cardiac output levels between CFS and control groups were corrected by controlling for cardiac contractility and TBV (total blood volume). The 146 participants were subdivided into two CFS groups based on symptom severity data, severe (n=30) and non-severe (n=26), and two healthy non-CFS control groups based on physical activity, sedentary (n=58) and non-sedentary (n=32). Controls were matched to CFS participants using age, gender, ethnicity and body mass. Echocardiographic measures indicated that the severe CFS participants had 10.2% lower cardiac volume (i.e. stroke index and end-diastolic volume) and 25.1% lower contractility (velocity of circumferential shortening corrected by heart rate) than the control groups. Dual tag blood volume assessments indicated that the CFS groups had lower TBV, PV (plasma volume) and RBCV (red blood cell volume) than control groups. Of the CFS subjects with a TBV deficit (i.e. > or = 8% below ideal levels), the mean+/-S.D. percentage deficit in TBV, PV and RBCV were -15.4+/-4.0, -13.2+/-5.0 and -19.1+/-6.3% respectively. Lower cardiac volume levels in CFS were substantially corrected by controlling for prevailing TBV deficits, but were not affected by controlling for cardiac contractility levels. Analyses indicated that the TBV deficit explained 91-94% of the group differences in cardiac volume indices. Group differences in cardiac structure were offsetting and, hence, no differences emerged for left ventricular mass index. Therefore the findings indicate that lower cardiac volume levels, displayed primarily by subjects with severe CFS, were not linked to diminished cardiac contractility levels, but were probably a consequence of a co-morbid hypovolaemic condition. Further study is needed to address

  17. Measurement and determinants of infrarenal aortic thrombus volume

    Energy Technology Data Exchange (ETDEWEB)

    Golledge, Jonathan; Wolanski, Philippe [James Cook University, The Vascular Biology Unit, Townsville, Queensland (Australia); Townsville Hospital, Townsville, Queensland (Australia); Parr, Adam [James Cook University, The Vascular Biology Unit, Townsville, Queensland (Australia); Buttner, Petra [James Cook University, School of Public Health and Tropical Medicine, Townsville, Queensland (Australia)

    2008-09-15

    Intra-luminal thrombus has been suggested to play a role in the progression of abdominal aortic aneurysm (AAA). The aims of this study were twofold. Firstly, to assess the reproducibility of a computer tomography (CT)-based technique for measurement of aortic thrombus volume. Secondly, to examine the determinants of infrarenal aortic thrombus volume in a cohort of patients with aortic dilatation. A consecutive series of 75 patients assessed by CT angiography with maximum aortic diameter {>=}25 mm were recruited. Intra-luminal thrombus volume was measured by a semi-automated workstation protocol based on a previously defined technique to quantitate aortic calcification. Intra- and inter-observer reproducibility were assessed using correlation coefficients, coefficient of variation and Bland-Altman plots. Infrarenal aortic thrombus volume percentage was related to clinical, anatomical and blood characteristics of the patients using univariate and multivariate tests. Infrarenal aortic thrombus volume was related to the severity of aortic dilatation assessed by total aortic volume (r=0.87, P<0.0001) or maximum aortic diameter (r=0.74, P< 0.0001). We therefore examined the clinical determinates of aortic thrombus expressed as a percentage of total aortic volume. Aortic thrombus percentage was negatively correlated with serum high density lipoprotein (HDL, r=-0.31). By ordinal multiple logistic regression analysis serum HDL below median ({<=}1.2 mM) was associated with aortic thrombus percentage in the upper quartile adjusting for other risk factors (odds ratio 5.3, 95% CI 1.1-25.0). Infrarenal aortic thrombus volume can be measured reproducibly on CT. Serum HDL, which can be therapeutically raised, may play a role in discouraging aortic thrombus accumulation with implications in terms of delaying progression of AAA. (orig.)

  18. Lung function, transfusion, pulmonary capillary blood volume and sickle cell disease.

    Science.gov (United States)

    Lunt, Alan; McGhee, Emily; Robinson, Polly; Rees, David; Height, Susan; Greenough, Anne

    2016-02-01

    Lung function abnormalities occur in children with sickle cell disease (SCD) and may be associated with elevated pulmonary blood volume. To investigate that association, we determined whether blood transfusion in SCD children acutely increased pulmonary capillary blood volume (PCBV) and increased respiratory system resistance (Rrs5). Measurements of Rrs5 and spirometry were made before and after blood transfusion in 18 children, median age 14.2 (6.6-18.5) years. Diffusing capacity for carbon monoxide and nitric oxide were assessed to calculate the PCBV. Post transfusion, the median Rrs5 had increased from 127.4 to 141.3% predicted (pvolume from 39.7 to 64.1 ml/m2 (pvolume in one second (p=0.0056) and vital capacity (p=0.0008) decreased. The increase in Rrs5 correlated with the increase in PCBV (r=0.50, p=0.0493). Increased pulmonary capillary blood volume may at least partially explain the lung function abnormalities in SCD children.

  19. 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.

  20. Facilitating cartilage volume measurement using MRI

    Energy Technology Data Exchange (ETDEWEB)

    Maataoui, Adel, E-mail: adel.maataoui@gmx.d [Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Gurung, Jessen, E-mail: jessen.gurung@gmx.d [Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Ackermann, Hanns, E-mail: h.ackermann@add.uni-frankfurt.d [Institute for Epidemiology and Medical Statistics, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Abolmaali, Nasreddin [Biological and Molecular Imaging, ZIK OncoRay - Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307 Dresden (Germany); Kafchitsas, Konstantinos [Department of Orthopedics and Orthopedic Surgery, Johannes Gutenberg University, Langenbeckstrasse 1, 55131 Mainz (Germany); Vogl, Thomas J., E-mail: t.vogl@em.uni-frankfurt.d [Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Khan, M. Fawad, E-mail: fawad@gmx.d [Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany)

    2010-08-15

    Purpose: To compare quantitative cartilage volume measurement (CVM) using different slice thicknesses. Materials and methods: Ten knees were scanned with a 1.5 T MRI (Sonata, Siemens, Erlangen, Germany) using a 3D gradient echo sequence (FLASH, fast low-angle shot). Cartilage volume of the medial and lateral tibial plateau was measured by two independent readers in 1.5 mm, 3.0 mm and 5.0 mm slices using the Argus software application. Accuracy and time effectiveness served as control parameters. Results: Determining cartilage volume, time for calculation diminished for the lateral tibial plateau from 384.6 {+-} 127.7 s and 379.1 {+-} 117.6 s to 214.9 {+-} 109.9 s and 213.9 {+-} 102.2 s to 122.1 {+-} 60.1 s and 126.8 {+-} 56.2 s and for the medial tibial plateau from 465.0 {+-} 147.7 s and 461.8 {+-} 142.7 s to 214.0 {+-} 67.9 s and 208.9 {+-} 66.2 s to 132.6 {+-} 41.5 s and 130.6 {+-} 42.0 s measuring 1.5 mm, 3 mm and 5 mm slices, respectively. No statistically significant difference between cartilage volume measurements was observed (p > 0.05) while very good inter-reader correlation was evaluated. Conclusion: CVM using 1.5 mm slices provides no higher accuracy than cartilage volume measurement in 5 mm slices while an overall time saving up to 70% is possible.

  1. Regional cerebral blood flow and blood volume in patients with subcortical arteriosclerotic encephalopathy (SAE).

    Science.gov (United States)

    Gückel, Friedemann J; Brix, Gunnar; Hennerici, Michael; Lucht, Robert; Ueltzhöffer, Christine; Neff, Wolfgang

    2007-10-01

    The aim of the present study was a detailed analysis of the regional cerebral blood flow and blood volume in patients with subcortical arteriosclerotic encephalopathy (SAE) by means of functional magnetic resonance imaging (MRI). A group of 26 patients with SAE and a group of 16 age-matched healthy volunteers were examined. Using a well-established dynamic susceptibility contrast-enhanced MRI method, the regional cerebral blood flow (rCBF) and blood volume (rCBV) were quantified for each subject in 12 different regions in the brain parenchyma. As compared to healthy volunteers, patients with SAE showed significantly reduced rCBF and rCBV values in white matter regions and in the occipital cortex. Regions containing predominantly grey matter show almost normal rCBF and rCBV values. In conclusion, quantitative analysis of rCBF and rCBV values demonstrates clearly that SAE is a disease that is associated with a reduced microcirculation predominantly in white matter.

  2. The critical relationship of intravascular blood volume and vascular capacitance in sepsis.

    Science.gov (United States)

    Thal, A P; Robinson, R G; Nagamine, T; Pruett, R; Wegst, A V

    1976-07-01

    The present article represents a more detailed study of the septic leg models used in our previous work on sepsis and septic shock. An improvement in this model is described, and the period of maximum hyperdynamic response is delineated. An attempt was made to measure changes in the rate of swelling of the septic leg in responding and nonresponding dogs. The exquisitely sensitive response of the dog with sepsis to minor reductions in blood volume was demonstrated. Results of our previous studies concerning the redistribution of blood flow in sepsis were extended using radioactively labeled microspheres.

  3. Noninvasive methods of measuring bone blood perfusion

    OpenAIRE

    Dyke, J. P.; Aaron, R.K.

    2010-01-01

    Measurement of bone blood flow and perfusion characteristics in a noninvasive and serial manner would be advantageous in assessing revascularization after trauma and the possible risk of avascular necrosis. Many disease states, including osteoporosis, osteoarthritis, and bone neoplasms, result in disturbed bone perfusion. A causal link between bone perfusion and remodeling has shown its importance in sustained healing and regrowth following injury. Measurement of perfusion and permeability wi...

  4. Blood Glucose Measurement Using Bioimpedance Technique

    Directory of Open Access Journals (Sweden)

    D. K. Kamat

    2014-01-01

    Full Text Available Bioimpedance measurement is gaining importance in wide field of bioresearch and biomedical systems due to its noninvasive nature. Noninvasive measurement method is very important to decrease infection and physical injuries which result due to invasive measurement. This paper presents basic principle of bioimpedance along with its application for blood glucose analysis and effect of frequency on impedance measurement. Input from bioimpedance sensor is given to amplifier and signal conditioner AD5933. AD5933 is then interfaced with microcontroller LPC1768 using I2C bus for displaying reading on LCD. Results can also be stored in database using UART interface of LPC1768.

  5. Blood volume changes after radiotherapy of the CNS; Blutvolumenveraenderungen nach Strahlentherapie des zentralen Nervensystems

    Energy Technology Data Exchange (ETDEWEB)

    Wenz, F. [Radiologische Universitaetsklinik, Heidelberg (Germany); Fuss, M. [Radiologische Universitaetsklinik, Heidelberg (Germany); Scholdei, R. [Radiologische Universitaetsklinik, Heidelberg (Germany); Essig, M. [Abt. Onkologische Diagnostik und Therapie, Deutsches Krebsforschungszentrum, Heidelberg (Germany); Lohr, F. [Radiologische Universitaetsklinik, Heidelberg (Germany); Rempp, K. [Abt. Klinische Neuroradiologie, Univ. Heidelberg (Germany); Brix, G. [Abt. Biophysik und Medizinische Strahlenphysik, Deutsches Krebsforschungszentrum, Heidelberg (Germany); Knopp, M.V. [Abt. Onkologische Diagnostik und Therapie, Deutsches Krebsforschungszentrum, Heidelberg (Germany); Engenhart, R. [Radiologische Universitaetsklinik, Heidelberg (Germany); Wannenmacher, M. [Radiologische Universitaetsklinik, Heidelberg (Germany)

    1996-10-01

    The pathogenesis of late delayed radiation damage in normal brain tissue is most likely due to damage to the vascular endothelium. The mitotic activity of gliomas was shown to correlate with the tumor induced angiogenesis. Dynamic susceptibility contrast MR imaging (DSC MRI) allows the measurement of the cerebral hemodynamics based on the indicator dilution theory. We describe theory and technique of the method and present our experience with blood volume measurements after irradiation of the CNS. We established a double slice technique on a standard 1.5 T MR system without hardware modifications, which allows an absolute quantification of the blood volume in regions of interest (ROI) within the brain. Fifty-five T2* weighted double slice images were acquired before, during and after bolus injection of Gd-DTPA (0.1 mmol/kg in 5 sec.) using a SD FLASH sequence (simultaneous dual fast low angle shot, TR/TE1/TE2 31/16/25, flip angle 10 ). Concentration-time curves were calculated from the measured signal-time curves. Blood volume values in tissue were normalised and calculated in absolute values (ml/100 g) based on the knowledge of the arterial input function (AIF), which was measured in the brain supplying arteries. The whole procedure requires only 2 to 3 minutes, the time for post processing is about 15 to 20 minutes. Blood volume parameter images of representative cases demonstrate the blood volume changes after radiotherapy. A reduction in blood volume could be observed in normal brain tissue and low-grade gliomas, while recurrent tumors were accompanied by a local increase in blood volume. Radiation induced blood volume changes in the CNS can be measured using dynamic susceptibility contrast MR imaging. The measurements in normal brain tissue allow a functional in-vivo analysis of late delayed radiation reactions of the CNS. (orig.) [Deutsch] Die Pathogenese von Strahlenspaetfolgen am Gehirn wird auf eine Schaedigung der Gefaessendothelien zurueckgefuehrt. Die

  6. Cerebral blood volume in humans by NIRS and PET

    Science.gov (United States)

    Pott, Frank; Knudsen, Gitte M.; Rostrup, Egill; Ide, Kojiro; Secher, Niels H.; Paulson, Olaf B.

    1998-01-01

    Near infrared spectroscopy (NIRS) determined changes in the cerebral blood volume (CBV) were compared to those obtained by positron emission tomography (PET) in five healthy volunteers (2 females). Two NIRS optodes were placed on the left forehead and NIRS-CBV was derived from the sum of oxyhemoglobin and deoxyhemoglobin. CBV changes were induced by hyperventilation and inhalation of 6% CO2. After 2 min inhalation of labeled carbon monoxide, data were sampled during 8 min for both PET- and NIRS-CBV as well as for the arterial carbon dioxide tension (PaCO2). The region of interest for PET-CBV was `banana-shaped' with boundaries corresponding to the position of the NIRS optodes on the transmission scan and to a depth of approximately 2 cm. During hyperventilation, PaCO2 decreased from 5.2 (4.6 - 5.8) to 4.6 (4.2 - 4.9) kPa and equally PET-CBV (from 3.9 (2.5 - 5.2) to 3.6 (3.0 - 4.8) ml (DOT) 100 g-1) and NIRS-CBV were reduced (by -0.14 [-0.38 - 0.50] ml (DOT) 100 g-1). During hypercapnia PaCO2 increased to 6.0 (5.9 - 7.0) kPa accompanied by parallel changes in PET- (to 4.5 (3.9 - 4.9) ml (DOT) 100 g-1) and NIRS-CBV (by 0.04 [-0.02 - 0.30] ml (DOT) 100 g-1) and the two variables were correlated (r equals 0.78, p arterial carbon dioxide tension, the cerebral blood volumes determined by near infrared spectroscopy and by positron emission tomography change in parallel but the change in NIRS-CBV is small compared to that obtained by PET.

  7. Doppler sonography of diabetic feet: Quantitative analysis of blood flow volume

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Young Lan; Kim, Ho Chul; Choi, Chul Soon; Yoon, Dae Young; Han, Dae Hee; Moon, Jeung Hee; Bae, Sang Hoon [Hallym University College of Medicine, Seoul (Korea, Republic of)

    2002-09-15

    To analyze Doppler sonographic findings of diabetic feet by estimating the quantitative blood flow volume and by analyzing waveform on Doppler. Doppler sonography was performed in thirty four patients (10 diabetic patients with foot ulceration, 14 diabetic patients without ulceration and 10 normal patients as the normal control group) to measure the flow volume of the arteries of the lower extremities (posterior and anterior tibial arteries, and distal femoral artery. Analysis of doppler waveforms was also done to evaluate the nature of the changed blood flow volume of diabetic patients, and the waveforms were classified into triphasic, biphasic-1, biphasic-2 and monophasic patterns. Flow volume of arteries in diabetic patients with foot ulceration was increased witha statistical significance when compared to that of diabetes patients without foot ulceration of that of normal control group (P<0.05). Analysis of Doppler waveform revealed that the frequency of biphasic-2 pattern was significantly higher in diabetic patients than in normal control group(p<0.05). Doppler sonography in diabetic feet showed increased flow volume and biphasic Doppler waveform, and these findings suggest neuropathy rather than ischemic changes in diabetic feet.

  8. Acute blood volume expansion delays the gastrointestinal transit of a charcoal meal in awake rats

    Directory of Open Access Journals (Sweden)

    de-Oliveira G.R.

    1998-01-01

    Full Text Available The present study evaluates the effect of blood volume expansion on the gastrointestinal transit of a charchoal meal (2.5 ml of an aqueous suspension consisting of 5% charcoal and 5% gum arabic in awake male Wistar rats (200-270 g. On the day before the experiments, the rats were anesthetized with ether, submitted to left jugular vein cannulation and fasted with water ad libitum until 2 h before the gastrointestinal transit measurement. Blood volume expansion by iv infusion of 1 ml/min Ringer bicarbonate in volumes of 3, 4 or 5% body weight delayed gastrointestinal transit at 10 min after test meal administration by 21.3-26.7% (P<0.05, but no effect was observed after 1 or 2% body weight expansion. The effect of blood volume expansion (up to 5% body weight on gastrointestinal transit lasted for at least 60 min (P<0.05. Mean arterial pressure increased transiently and central venous pressure increased and hematocrit decreased (P<0.05. Subdiaphragmatic vagotomy and yohimbine (3 mg/kg prevented the delay caused by expansion on gastrointestinal transit, while atropine (0.5 mg/kg, L-NAME (2 mg/kg, hexamethonium (10 mg/kg, prazosin (1 mg/kg or propranolol (2 mg/kg were ineffective. These data show that blood volume expansion delays the gastrointestinal transit of a charcoal meal and that vagal and yohimbine-sensitive pathways appear to be involved in this phenomenon. The delay in gastrointestinal transit observed here, taken together with the modifications of gastrointestinal permeability to salt and water reported by others, may be part of the mechanisms involved in liquid excess management.

  9. Orthostatic leg blood volume changes assessed by near-infrared spectroscopy

    DEFF Research Database (Denmark)

    Truijen, J; Kim, Y S; Krediet, C T P

    2012-01-01

    Standing up shifts blood to dependent parts of the body, and blood vessels in the leg become filled. The orthostatic blood volume accumulation in the small vessels is relatively unknown, although these may contribute significantly. We hypothesized that in healthy humans exposed to the upright...... posture, volume accumulation in small blood vessels contributes significantly to the total fluid volume accumulated in the legs. Considering that near-infrared spectroscopy (NIRS) tracks postural blood volume changes within the small blood vessels of the lower leg, we evaluated the NIRS-determined changes......-linear accumulation of blood volume in the small vessels of the leg, with an initial fast phase followed by a more gradual increase at least partly contributing to the relocation of fluid during orthostatic stress....

  10. Effects of passive heating on central blood volume and ventricular dimensions in humans

    DEFF Research Database (Denmark)

    Crandall, C.G.; Wilson, T.E.; Marving, J.;

    2008-01-01

    Mixed findings regarding the effects of whole-body heat stress on central blood volume have been reported. This study evaluated the hypothesis that heat stress reduces central blood volume and alters blood volume distribution. Ten healthy experimental and seven healthy time control (i.e. non-heat...... plus central vasculature (17 +/- 2%), thorax (14 +/- 2%), inferior vena cava (23 +/- 2%) and liver (23 +/- 2%) (all P Udgivelsesdato: 2008/1/1...

  11. Blood volume, blood pressure and total body sodium: internal signalling and output control

    DEFF Research Database (Denmark)

    Bie, P

    2009-01-01

    Total body sodium and arterial blood pressure (ABP) are mutually dependent variables regulated by complex control systems. This review addresses the role of ABP in the normal control of sodium excretion (NaEx), and the physiological control of renin secretion. NaEx is a pivotal determinant of ABP...... and the regulation of NaEx via a hypothetical integrative control system. However, recent data show that subtle sodium loading (simulating salty meals) causes robust natriuresis without changes in ABP. Changes in ABP are not necessary for natriuresis. Normal sodium excretion is not regulated by pressure. Plasma......, and under experimental conditions, ABP is a powerful, independent controller of NaEx. Blood volume is a function of dietary salt intake; however, ABP is not, at least not in steady states. A transient increase in ABP after a step-up in sodium intake could provide a causal relationship between ABP...

  12. Determination of volume, shape and refractive index of individual blood platelets

    CERN Document Server

    Kolesnikova, Irina V; Yurkin, Maxim A; Hoekstra, Alfons G; Maltsev, Valeri P; Semyanov, Konstantin A

    2008-01-01

    Light scattering patterns (LSP) of blood platelets were theoretically and experimentally analyzed. We used spicular spheroids as a model for the platelets with pseudopodia. The discrete dipole approximation was employed to simulate light scattering from an individual spicular spheroid constructed from a homogeneous oblate spheroid and 14 rectilinear parallelepipeds rising from the cell centre. These parallelepipeds have a weak effect on the LSP over the measured angular range. Therefore, a homogeneous oblate spheroid was taken as a simplified optical model for platelets. Using the T-matrix method, we computed the LSP over a range of volumes, aspect ratios and refractive indices. Measured LSPs of individual platelets were compared one by one with the theoretical set and the best fit was taken to characterize the measured platelets, resulting in distributions of volume, aspect ratio and refractive index.

  13. 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.

  14. Plasma volume expansion by albumin in cirrhosis. Relation to blood volume distribution, arterial compliance and severity of disease

    DEFF Research Database (Denmark)

    Brinch, Kim; Bendtsen, Flemming; Becker, Povl Ulrik;

    2003-01-01

    BACKGROUND/AIMS: The aim of the study was to investigate the effect of a standard albumin load on blood volume distribution, arterial compliance, and the renin-angiotensin-aldosterone system in patients with different degrees of cirrhosis. METHODS: 31 patients with cirrhosis (Child classes A/B/C=...... effective arterial blood volume of such patients, which may be important in the prevention of circulatory dysfunction....

  15. Database of normal human cerebral blood flow, cerebral blood volume, cerebral oxygen extraction fraction and cerebral metabolic rate of oxygen measured by positron emission tomography with {sup 15}O-labelled carbon dioxide or water, carbon monoxide and oxygen: a multicentre study in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi [Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita (Japan); Department of Nuclear Medicine and Radiology, Division of Brain Sciences, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-Machi, 980-8575, Aoba-Ku, Sendai (Japan); Kanno, Iwao [Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita (Japan); Kato, Chietsugu [Department of Nuclear Medicine, Hokkaido University School of Medicine, Sapporo (Japan); Sasaki, Toshiaki [Cyclotoron Research Center, Iwate Medical University, Morioka (Japan); Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo (Japan); Ouchi, Yasuomi [Positron Medical Center, Hamamatsu Medical Center, Hamakita (Japan); Iida, Akihiko [Nagoya City Rehabilitation Center, Nagoya (Japan); Okazawa, Hidehiko [PET Unit, Research Institute, Shiga Medical Center, Moriyama (Japan); Hayashida, Kohei [Department of Radiology, National Cardiovascular Center, Suita, Osaka (Japan); Tsuyuguchi, Naohiro [Department of Neurosurgery, Osaka City University Medical School, Osaka (Japan); Ishii, Kazunari [Division of Imaging Research, Hyogo Institute for Aging Brain and Cognitive Disorders, Himeji, Hyogo (Japan); Kuwabara, Yasuo [Department of Radiology, Faculty of Medicine, Kyushu University, Fukuoka (Japan); Senda, Michio [Department of Image-based Medicine, Institute of Biomedical Research and Innovation, Kobe (Japan)

    2004-05-01

    Measurement of cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO{sub 2}) by positron emission tomography (PET) with oxygen-15 labelled carbon dioxide (C{sup 15}O{sub 2}) or {sup 15}O-labelled water (H{sub 2}{sup 15}O), {sup 15}O-labelled carbon monoxide (C{sup 15}O) and {sup 15}O-labelled oxygen ({sup 15}O{sub 2}) is useful for diagnosis and treatment planning in cases of cerebrovascular disease. The measured values theoretically depend on various factors, which may differ between PET centres. This study explored the applicability of a database of {sup 15}O-PET by examining between-centre and within-centre variation in values. Eleven PET centres participated in this multicentre study; seven used the steady-state inhalation method, one used build-up inhalation and three used bolus administration of C{sup 15}O{sub 2} (or H{sub 2}{sup 15}O) and {sup 15}O{sub 2}. All used C{sup 15}O for measurement of CBV. Subjects comprised 70 healthy volunteers (43 men and 27 women; mean age 51.8{+-}15.1 years). Overall mean{+-}SD values for cerebral cortical regions were: CBF=44.4{+-}6.5 ml 100 ml{sup -1} min{sup -1}; CBV=3.8{+-}0.7 ml 100 ml{sup -1}; OEF=0.44{+-}0.06; CMRO{sub 2}=3.3{+-}0.5 ml 100 ml{sup -1} min{sup -1}. Significant between-centre variation was observed in CBV, OEF and CMRO{sub 2} by one-way analysis of variance. However, the overall inter-individual variation in CBF, CBV, OEF and CMRO{sub 2} was acceptably small. Building a database of normal cerebral haemodynamics obtained by the{sup 15}O-PET methods may be practicable. (orig.)

  16. Circulating atrial natriuretic peptide (ANP) and central blood volume (CBV) in cirrhosis

    DEFF Research Database (Denmark)

    Schütten, H J; Henriksen, Jens Henrik Sahl; Bendtsen, F

    1986-01-01

    or diuretic treatment. Central blood volume (CBV, i.e. the blood volume in the heart cavities, lungs, and aorta), determined from the mean transit time of 125I-labelled of 125I-labelled albumin and cardiac output, was significantly reduced in cirrhotics compared to controls (1.45 +/- 0.12 vs. 1.83 +/- 0.10 l...

  17. Precision of a new bedside method for estimation of the circulating blood volume

    DEFF Research Database (Denmark)

    Christensen, P; Eriksen, B; Henneberg, S W

    1993-01-01

    The present study is a theoretical and experimental evaluation of a modification of the carbon monoxide method for estimation of the circulating blood volume (CBV) with respect to the precision of the method. The CBV was determined from measurements of the CO-saturation of hemoglobin before...... and after ventilation with a gas mixture containing 20-50 ml of CO for a period of 10-15 min. A special Water's to and fro system was designed in order to avoid any leakage when measuring during intermittent positive pressure ventilation (IPPV). Blood samples were taken before and immediately after......, determination of CBV can be performed with an amount of CO that gives rise to a harmless increase in the carboxyhemoglobin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)...

  18. Optical oximetry of volume-oscillating vascular compartments: contributions from oscillatory blood flow

    Science.gov (United States)

    Kainerstorfer, Jana M.; Sassaroli, Angelo; Fantini, Sergio

    2016-10-01

    We present a quantitative analysis of dynamic diffuse optical measurements to obtain oxygen saturation of hemoglobin in volume oscillating compartments. We used a phasor representation of oscillatory hemodynamics at the heart rate and respiration frequency to separate the oscillations of tissue concentrations of oxyhemoglobin (O) and deoxyhemoglobin (D) into components due to blood volume (subscript V) and blood flow (subscript F): O=OV+OF, D=DV+DF. This is achieved by setting the phase angle Arg(OF)-Arg(O), which can be estimated by a hemodynamic model that we recently developed. We found this angle to be -72 deg for the cardiac pulsation at 1 Hz, and -7 deg for paced breathing at 0.1 Hz. Setting this angle, we can obtain the oxygen saturation of hemoglobin of the volume-oscillating vascular compartment, SV=|OV|/(|OV|+|DV|). We demonstrate this approach with cerebral near-infrared spectroscopy measurements on healthy volunteers at rest (n=4) and during 0.1 Hz paced breathing (n=3) with a 24-channel system. Rest data at the cardiac frequency were used to calculate the arterial saturation, S(a); over all subjects and channels, we found ==0.96±0.02. In the case of paced breathing, we found =0.66±0.14, which reflects venous-dominated hemodynamics at the respiratory frequency.

  19. Clinical Relevance of Brain Volume Measures in Multiple Sclerosis

    DEFF Research Database (Denmark)

    De Stefano, Nicola; Airas, Laura; Grigoriadis, Nikolaos

    2014-01-01

    in a disease with complex pathological substrates such as MS. Brain volume loss has been correlated with disability progression and cognitive impairment in MS, with the loss of grey matter volume more closely correlated with clinical measures than loss of white matter volume. Preventing brain volume loss may...

  20. Blood culture volume and detection of coagulase negative staphylococcal septicaemia in neonates

    OpenAIRE

    Jawaheer, G; Neal, T; Shaw, N.

    1997-01-01

    A prospective, blind study was carried out to determine: the amount of blood submitted for culture from neonates; whether small blood volumes resulted in false negative results; and whether there was a temporal relation between volume of blood cultured and time to positivity.
  Seventy three bottles were evaluated. They contained a median of 0.63 ml of blood. Twenty nine bottles (39.7%) contained less than 0.5 ml of blood; 21 bottles (28.8%) were positive. There were three false negative cult...

  1. Does Preinterventional Flat-Panel Computer Tomography Pooled Blood Volume Mapping Predict Final Infarct Volume After Mechanical Thrombectomy in Acute Cerebral Artery Occlusion?

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Marlies, E-mail: marlies.wagner@kgu.de [Hospital of Goethe University, Institute of Neuroradiology (Germany); Kyriakou, Yiannis, E-mail: yiannis.kyriakou@siemens.com [Siemens AG, Health Care Sector (Germany); Mesnil de Rochemont, Richard du, E-mail: mesnil@em.uni-frankfurt.de [Hospital of Goethe University, Institute of Neuroradiology (Germany); Singer, Oliver C., E-mail: o.singer@em.uni-frankfurt.de [Hospital of Goethe University, Department of Neurology (Germany); Berkefeld, Joachim, E-mail: berkefeld@em.uni-frankfurt.de [Hospital of Goethe University, Institute of Neuroradiology (Germany)

    2013-08-01

    PurposeDecreased cerebral blood volume is known to be a predictor for final infarct volume in acute cerebral artery occlusion. To evaluate the predictability of final infarct volume in patients with acute occlusion of the middle cerebral artery (MCA) or the distal internal carotid artery (ICA) and successful endovascular recanalization, pooled blood volume (PBV) was measured using flat-panel detector computed tomography (FPD CT).Materials and MethodsTwenty patients with acute unilateral occlusion of the MCA or distal ACI without demarcated infarction, as proven by CT at admission, and successful Thrombolysis in cerebral infarction score (TICI 2b or 3) endovascular thrombectomy were included. Cerebral PBV maps were acquired from each patient immediately before endovascular thrombectomy. Twenty-four hours after recanalization, each patient underwent multislice CT to visualize final infarct volume. Extent of the areas of decreased PBV was compared with the final infarct volume proven by follow-up CT the next day.ResultsIn 15 of 20 patients, areas of distinct PBV decrease corresponded to final infarct volume. In 5 patients, areas of decreased PBV overestimated final extension of ischemia probably due to inappropriate timing of data acquisition and misery perfusion.ConclusionPBV mapping using FPD CT is a promising tool to predict areas of irrecoverable brain parenchyma in acute thromboembolic stroke. Further validation is necessary before routine use for decision making for interventional thrombectomy.

  2. Changes of Blood Flow Volume in the Superior Mesenteric Artery and Brachial Artery with Abdominal Thermal Stimulation

    Directory of Open Access Journals (Sweden)

    Shin Takayama

    2011-01-01

    Full Text Available In traditional Chinese medicine, moxibustion is a local thermal therapy that is used for several conditions. Quantifying the effects of moxibustion therapy has been difficult because the treatment temperature depends on the physician's experience, and the temperature distribution in the target area is not uniform. This prospective observational study aims to quantify the effect of local thermal stimulation to the abdomen. We developed a heat transfer control device (HTCD for local thermal stimulation. Twenty-four healthy subjects were enrolled and they underwent abdominal thermal stimulation to the para-umbilical region with the device for 20 min. Blood flow volume in the superior mesenteric artery (SMA and brachial artery (BA, the heart rate and the blood pressure were measured at rest, 15 min after starting thermal stimulation and 10, 20, 30 and 40 min after completing thermal stimulation. Blood flow parameters were measured by high-resolution ultrasound. In the SMA, blood flow volume was significantly increased during thermal stimulation (, as well as at 10 min ( and 20 min ( after stimulation. In the BA, blood flow volume decreased at 40 min after stimulation (. In conclusion we could quantify the effect of local thermal stimulation with an HTCD and high-resolution ultrasound. Thermal stimulation of the para-umbilical region increased blood flow in the SMA 20 min after stimulation in healthy subjects.

  3. Impedance cardiography: Pulsatile blood flow and the biophysical and electrodynamic basis for the stroke volume equations

    Directory of Open Access Journals (Sweden)

    Donald P Bernstein

    2010-01-01

    Full Text Available Impedance cardiography (ICG is a branch of bioimpedance pimarily concerned with the determination of left ventricular stroke volume (SV. As implemented, using the transthoracic approach, the technique involves applying a current field longitudinally across a segment of thorax by means of a constant magnitude, high frequency, low amplitude alternating current (AC. By Ohm's Law, the voltage difference measured within the current field is proportional to the electrical impedance Z (Ω. Without ventilatory or cardiac activity, Z is known as the transthoracic, static base impedance Z0. Upon ventricular ejection, a characteristic time dependent cardiac-synchronous pulsatile impedance change is obtained, ΔZ(t, which, when placed electrically in parallel with Z0, constitutes the time-variable total transthoracic impedance Z(t. ΔZ(t represents a dual-element composite waveform, which comprises both the radially-oriented volumetric expansion of and axially-directed forward blood flow within both great thoracic arteries. In its majority, however, ΔZ(t is known to primarily emanate from the ascending aorta. Conceptually, commonly implemented methods assume a volumetric origin for the peak systolic upslope of ΔZ(t, (i.e. dZ/dtmax, with the presumed units of Ω·s-1. A recently introduced method assumes the rapid ejection of forward flowing blood in earliest systole causes significant changes in the velocity-induced blood resistivity variation (Δρb(t, Ωcm·s-1, and it is the peak rate of change of the blood resistivity variation dρb(t/dtmax (Ωcm·s-2 that is the origin of dZ/dtmax. As a consequence of dZ/dtmax peaking in the time domain of peak aortic blood acceleration, dv/dtmax (cm·s-2, it is suggested that dZ/dtmax is an ohmic mean acceleration analog (Ω·s-2 and not a mean flow or velocity surrogate as generally assumed. As conceptualized, the normalized value, dZ/dtmax/Z0, is a dimensionless ohmic mean acceleration equivalent (s-2

  4. Rapid multi-wavelength optical assessment of circulating blood volume without a priori data

    Science.gov (United States)

    Loginova, Ekaterina V.; Zhidkova, Tatyana V.; Proskurnin, Mikhail A.; Zharov, Vladimir P.

    2016-03-01

    The measurement of circulating blood volume (CBV) is crucial in various medical conditions including surgery, iatrogenic problems, rapid fluid administration, transfusion of red blood cells, or trauma with extensive blood loss including battlefield injuries and other emergencies. Currently, available commercial techniques are invasive and time-consuming for trauma situations. Recently, we have proposed high-speed multi-wavelength photoacoustic/photothermal (PA/PT) flow cytometry for in vivo CBV assessment with multiple dyes as PA contrast agents (labels). As the first step, we have characterized the capability of this technique to monitor the clearance of three dyes (indocyanine green, methylene blue, and trypan blue) in an animal model. However, there are strong demands on improvements in PA/PT flow cytometry. As additional verification of our proof-of-concept of this technique, we performed optical photometric CBV measurements in vitro. Three label dyes—methylene blue, crystal violet and, partially, brilliant green—were selected for simultaneous photometric determination of the components of their two-dye mixtures in the circulating blood in vitro without any extra data (like hemoglobin absorption) known a priori. The tests of single dyes and their mixtures in a flow system simulating a blood transfusion system showed a negligible difference between the sensitivities of the determination of these dyes under batch and flow conditions. For individual dyes, the limits of detection of 3×10-6 M‒3×10-6 M in blood were achieved, which provided their continuous determination at a level of 10-5 M for the CBV assessment without a priori data on the matrix. The CBV assessment with errors no higher than 4% were obtained, and the possibility to apply the developed procedure for optical photometric (flow cytometry) with laser sources was shown.

  5. The effects of scraping therapy on local temperature and blood perfusion volume in healthy subjects.

    Science.gov (United States)

    Xu, Qin-Yan; Yang, Jin-Sheng; Zhu, Bing; Yang, Li; Wang, Ying-Ying; Gao, Xin-Yan

    2012-01-01

    Objective. We aim to study the therapeutic effects of scraping by investigating the changes of temperature and local blood perfusion volume in healthy subjects after scraping stimulation, and to explore the mechanism of scraping stimulation from the points of microcirculation and energy metabolism. Methods. Twenty-three health subjects were included in this study. Local blood perfusion volume and body surface temperature was detected at 5 min before scraping stimulation, 0, 15, 30, 60 and 90 min after scraping using Laser Doppler imager and infrared thermograph. Results. Significant increase was noted in the blood perfusion volume in the scraping area within 90 minutes compared to the baseline level and non-scraping area (P scraping area, an increase of body temperature with an average of 1°C was observed after scraping stimulation (P Scraping can significantly improve the blood perfusion volume and increase the temperature in the scraping area, promoting the local blood circulation and energy metabolism.

  6. Plasma catecholamines and blood volume in native Andeans during hypoxia and normoxia.

    Science.gov (United States)

    Gamboa, Alfredo; Gamboa, Jorge L; Holmes, Courtney; Sharabi, Yehonatan; Leon-Velarde, Fabiola; Fischman, Gary J; Appenzeller, Otto; Goldstein, David S

    2006-02-01

    Plasma catechols and blood volume were measured in 20 male, native high-altitude residents of Cerro de Pasco, Peru (4338 m), while hypoxic and subsequently while normoxic at sea level. Ten subjects were healthy controls,with hematocrits lower than 61%, and ten had chronic mountain sickness (CMS), a syndrome of maladaptation to altitude, characterized by polycythemia (hematocrit > 61%), profound hypoxemia, and neurologic symptoms. The main aim of the study was to evaluate the chronic effects of hypoxia on plasma catechols and on blood volume, by studying these parameters during hypoxia at high altitude (HA) and shortly after exposure to normoxia at sea level (SL). Subjects were first studied at HA in their habitual hypoxic environment, and measurements were repeated within 4 hours of arrival at SL (Lima, Peru, 150 m). All subjects had higher plasma norepinephrine (NE), dopamine (DA), and dihydroxyphenylglycol (DHPG) levels in HA (NE in controls and CMS: 414+/-47 and 514+/-35 pg/mL; DA: 9+/-1 and 13+/-1 pg/mL, DHPG: 817+/-48 and 972+/-77 pg/mL) than at SL (NE: 164+/-9 and 243+/-28 pg/mL; DA: 4+/-0.5 and 5+/-1 pg/mL DHPG: 502+/-23 and 649+/-39 pg/mL). Group differences were statistically significant only for NE in the CMS group. Plasma volume was higher in HA in both groups (p<0.05); red cell volume was higher in HA only in the CMS group. The results indicate sympathetic nervous stimulation by chronic ambient hypoxia at altitude in Andean natives, independent of maladaptation to their native environment.

  7. Prefrontal cerebral blood volume patterns while playing video games--a near-infrared spectroscopy study.

    Science.gov (United States)

    Nagamitsu, Shinichiro; Nagano, Miki; Yamashita, Yushiro; Takashima, Sachio; Matsuishi, Toyojiro

    2006-06-01

    Video game playing is an attractive form of entertainment among school-age children. Although this activity reportedly has many adverse effects on child development, these effects remain controversial. To investigate the effect of video game playing on regional cerebral blood volume, we measured cerebral hemoglobin concentrations using near-infrared spectroscopy in 12 normal volunteers consisting of six children and six adults. A Hitachi Optical Topography system was used to measure hemoglobin changes. For all subjects, the video game Donkey Kong was played on a Game Boy device. After spectroscopic probes were positioned on the scalp near the target brain regions, the participants were asked to play the game for nine periods of 15s each, with 15-s rest intervals between these task periods. Significant increases in bilateral prefrontal total-hemoglobin concentrations were observed in four of the adults during video game playing. On the other hand, significant decreases in bilateral prefrontal total-hemoglobin concentrations were seen in two of the children. A significant positive correlation between mean oxy-hemoglobin changes in the prefrontal region and those in the bilateral motor cortex area was seen in adults. Playing video games gave rise to dynamic changes in cerebral blood volume in both age groups, while the difference in the prefrontal oxygenation patterns suggested an age-dependent utilization of different neural circuits during video game tasks.

  8. Changes in circulating blood volume after infusion of hydroxyethyl starch 6% in critically ill patients

    DEFF Research Database (Denmark)

    Christensen, P; Andersson, J; Rasmussen, S E;

    2001-01-01

    The cardiovascular response to a volume challenge with hydroxyethyl starch (HES) (200/0.5) 6% depends on the relation between the volume of HES 6% infused and the expansion of the blood volume in critically ill patients. However, only relatively limited data exist on the plasma expanding effect...... of infusion of HES 6% in critically ill patients. The purpose of the study was to evaluate the variation in the expansion of the circulating blood volume (CBV) in critically ill patients after infusion of 500 ml of colloid (HES (200/0.5) 6%) using the carbon monoxide method....

  9. Blood volume distribution in patients with cirrhosis: aspects of the dual-head gamma-camera technique

    DEFF Research Database (Denmark)

    Kiszka-Kanowitz, Marianne; Henriksen, Jens Henrik; Møller, Søren;

    2001-01-01

    : The close relation between the estimated blood volume in the thorax region and the central and arterial blood volume, obtained by the dynamic indicator dilution technique (r=0.87, PWhole-body scintigraphy showed altered blood volume distribution in the cirrhotic...

  10. Blood flow measurements and clot detection with nearinfrared spectroscopy

    OpenAIRE

    Rossow, MJ; Gatto, R.; D'amico, E.; Mantulin, WW; Gratton, E

    2006-01-01

    Detecting impeded blood flow and locating the clot causing it is a major challenge in neurosurgery. We propose an instrument that uses near-infrared spectroscopy to simultaneously detect clots and measure blood flow. © 2006 Optical Society of America.

  11. [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.

  12. Ventilatory response in metabolic acidosis and cerebral blood volume in humans.

    NARCIS (Netherlands)

    Ven, M.T.P. van de; Colier, W.N.J.M.; Sluijs, M.C. van der; Oeseburg, B.; Folgering, H.T.M.

    2001-01-01

    The relationship between alterations in cerebral blood volume (CBV) and central chemosensitivity regulation was studied under neutral metabolic conditions and during metabolic acidosis. Fifteen healthy subjects (5610 years) were investigated. To induce metabolic acidosis, ammonium chloride (NH(4)Cl)

  13. Cardiovascular regulatory response to lower body negative pressure following blood volume loss

    Science.gov (United States)

    Shimizu, M.; Ghista, D. N.; Sandler, H.

    1979-01-01

    An attempt is made to explain the cardiovascular regulatory responses to lower body negative pressure (LBNP) stress, both in the absence of and following blood or plasma volume loss, the latter being factors regularly observed with short- or long-term recumbency or weightlessness and associated with resulting cardiovascular deconditioning. Analytical expressions are derived for the responses of mean venous pressure and blood volume pooled in the lower body due to LBNP. An analysis is presented for determining the HR change due to LBNP stress following blood volume loss. It is concluded that the reduced orthostatic tolerance following long-term space flight or recumbency can be mainly attributed to blood volume loss, and that the associated cardiovascular responses characterizing this orthostatic intolerance is elicited by the associated central venous pressure response.

  14. Determining tumor blood flow parameters from dynamic image measurements

    Science.gov (United States)

    Libertini, Jessica M.

    2008-11-01

    Many recent cancer treatments focus on preventing angiogenesis, the process by which a tumor promotes the growth of large and efficient capillary beds for the increased nourishment required to support the tumor's rapid growth[l]. To measure the efficacy of these treatments in a timely fashion, there is an interest in using data from dynamic sequences of contrast-enhanced medical imaging, such as MRI and CT, to measure blood flow parameters such as perfusion, permeability-surface-area product, and the relative volumes of the plasma and extracellular-extravascular space. Starting with a two compartment model presented by the radiology community[2], this work challenges the application of a simplification to this problem, which was originally developed to model capillary reuptake[3]. While the primary result of this work is the demonstration of the inaccuracy of this simplification, the remainder of the paper is dedicated to presenting alternative methods for calculating the perfusion and plasma volume coefficients. These methods are applied to model data sets based on real patient data, and preliminary results are presented.

  15. Determining tumor blood flow parameters from dynamic image measurements

    Energy Technology Data Exchange (ETDEWEB)

    Libertini, Jessica M [Division of Applied Mathematics, Brown University, Providence, Rhode Island 02906 (United States)], E-mail: Jessica_Libertini@brown.edu

    2008-11-01

    Many recent cancer treatments focus on preventing angiogenesis, the process by which a tumor promotes the growth of large and efficient capillary beds for the increased nourishment required to support the tumor's rapid growth. To measure the efficacy of these treatments in a timely fashion, there is an interest in using data from dynamic sequences of contrast-enhanced medical imaging, such as MRI and CT, to measure blood flow parameters such as perfusion, permeability-surface-area product, and the relative volumes of the plasma and extracellular-extravascular space. Starting with a two compartment model presented by the radiology community, this work challenges the application of a simplification to this problem, which was originally developed to model capillary reuptake. While the primary result of this work is the demonstration of the inaccuracy of this simplification, the remainder of the paper is dedicated to presenting alternative methods for calculating the perfusion and plasma volume coefficients. These methods are applied to model data sets based on real patient data, and preliminary results are presented.

  16. 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....

  17. Volume of blood suctioned during vacuum-assisted breast biopsy predicts later hematoma formation

    Directory of Open Access Journals (Sweden)

    Panopoulou Effrosyni

    2010-03-01

    Full Text Available Abstract Background To evaluate whether the volume of blood suctioned during vacuum-assisted breast biopsy (VABB is associated with hematoma formation and progression, patient's age and histology of the lesion. Findings 177 women underwent VABB according to standardized protocol. The volume of blood suctioned and hematoma formation were noted at the end of the procedure, as did the subsequent development and progression of hematoma. First- and second-order logistic regression was performed, where appropriate. Cases with hematoma presented with greater volume of blood suctioned (63.8 ± 44.7 cc vs. 17.2 ± 32.9 cc; p Conclusion The likelihood of hematoma is increasing along with increasing amount of blood suctioned, reaching a plateau approximately at 80 cc of blood lost.

  18. The Effects of Scraping Therapy on Local Temperature and Blood Perfusion Volume in Healthy Subjects

    OpenAIRE

    Qin-Yan Xu; Jin-Sheng Yang; Bing Zhu; Li Yang; Ying-Ying Wang; Xin-Yan Gao

    2012-01-01

    Objective. We aim to study the therapeutic effects of scraping by investigating the changes of temperature and local blood perfusion volume in healthy subjects after scraping stimulation, and to explore the mechanism of scraping stimulation from the points of microcirculation and energy metabolism. Methods. Twenty-three health subjects were included in this study. Local blood perfusion volume and body surface temperature was detected at 5 min before scraping stimulation, 0, 15, 30, 60 and 90 ...

  19. [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.

  20. Reference values for total blood volume and cardiac output in humans

    Energy Technology Data Exchange (ETDEWEB)

    Williams, L.R. [Indiana Univ., South Bend, IN (United States). Division of Liberal Arts and Sciences

    1994-09-01

    Much research has been devoted to measurement of total blood volume (TBV) and cardiac output (CO) in humans but not enough effort has been devoted to collection and reduction of results for the purpose of deriving typical or {open_quotes}reference{close_quotes} values. Identification of normal values for TBV and CO is needed not only for clinical evaluations but also for the development of biokinetic models for ultra-short-lived radionuclides used in nuclear medicine (Leggett and Williams 1989). The purpose of this report is to offer reference values for TBV and CO, along with estimates of the associated uncertainties that arise from intra- and inter-subject variation, errors in measurement techniques, and other sources. Reference values are derived for basal supine CO and TBV in reference adult humans, and differences associated with age, sex, body size, body position, exercise, and other circumstances are discussed.

  1. Very low cerebral blood volume predicts parenchymal hematoma in acute ischemic stroke

    DEFF Research Database (Denmark)

    Hermitte, Laure; Cho, Tae-Hee; Ozenne, Brice;

    2013-01-01

    BACKGROUND AND PURPOSE: Parenchymal hematoma (PH) may worsen the outcome of patients with stroke. The aim of our study was to confirm the relationship between the volume of very low cerebral blood volume (CBV) and PH using a European multicenter database (I-KNOW). A secondary objective was to exp...

  2. Quantitative evaluation of myocardial function by a volume-normalized map generated from relative blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Fukami, Tadanori [Department of Bio-system Engineering, Faculty of Engineering, Yamagata University, Yonezawa, Yamagata 992-8510 (Japan); Sato, Hidenori [Department of Bio-system Engineering, Faculty of Engineering, Yamagata University, Yonezawa, Yamagata 992-8510 (Japan); Wu, Jin [Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575 (Japan); Lwin, Thet-Thet- [Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575 (Japan); Yuasa, Tetsuya [Department of Bio-system Engineering, Faculty of Engineering, Yamagata University, Yonezawa, Yamagata 992-8510 (Japan); Kawano, Satoru [Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575 (Japan); Iida, Keiji [Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575 (Japan); Akatsuka, Takao [Department of Bio-system Engineering, Faculty of Engineering, Yamagata University, Yonezawa, Yamagata 992-8510 (Japan); Hontani, Hidekata [Department of Computer Science and Engineering, Nagoya Institute of Technology, Aichi 466-8555 (Japan); Takeda, Tohoru [Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575 (Japan); Tamura, Masao [Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575 (Japan); Yokota, Hiroshi [Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575 (Japan)

    2007-07-21

    Our study aimed to quantitatively evaluate blood flow in the left ventricle (LV) of apical hypertrophic cardiomyopathy (APH) by combining wall thickness obtained from cardiac magnetic resonance imaging (MRI) and myocardial perfusion from single-photon emission computed tomography (SPECT). In this study, we considered paired MRI and myocardial perfusion SPECT from ten patients with APH and ten normals. Myocardial walls were detected using a level set method, and blood flow per unit myocardial volume was calculated using 3D surface-based registration between the MRI and SPECT images. We defined relative blood flow based on the maximum in the whole myocardial region. Accuracies of wall detection and registration were around 2.50 mm and 2.95 mm, respectively. We finally created a bull's-eye map to evaluate wall thickness, blood flow (cardiac perfusion) and blood flow per unit myocardial volume. In patients with APH, their wall thicknesses were over 10 mm. Decreased blood flow per unit myocardial volume was detected in the cardiac apex by calculation using wall thickness from MRI and blood flow from SPECT. The relative unit blood flow of the APH group was 1/7 times that of the normals in the apex. This normalization by myocardial volume distinguishes cases of APH whose SPECT images resemble the distributions of normal cases.

  3. Reduced compensatory responses to maintain central blood volume during hypovolemic stress in women with vasovagal syncope.

    Science.gov (United States)

    Skoog, Johan; Zachrisson, Helene; Länne, Toste; Lindenberger, Marcus

    2017-01-01

    Although vasovagal syncope (VVS) is a common clinical condition, the underlying pathophysiology is not fully understood. A decrease in cardiac output has recently been suggested as a factor in orthostatic VVS. The aim was to investigate compensatory mechanisms to maintain central blood volume and venous return during hypovolemic stress in women with VVS. Fourteen VVS women (25.7 ± 5.0 yr) and 15 matched controls (22.8 ± 3.2 yr) were investigated. Single-step and graded lower body negative pressure (LBNP) to presyncope were used to create hypovolemic stress. Peripheral mobilization of venous blood from the arm (capacitance response and net capillary fluid absorption) and lower limb blood pooling (calf capacitance response) were evaluated using a volumetric technique. Cardiovascular responses and plasma norepinephrine (P-NE) were measured. Resting P-NE was elevated in VVS women (P < 0.01). Despite a similar hypovolemic stimulus, the increase in P-NE was blunted (P < 0.01) and the maximal percent increase in total peripheral resistance was reduced (P < 0.05) during graded LBNP in VVS women. The arm capacitance response was slower (P < 0.05) and reduced in VVS women at higher levels of LBNP (P < 0.05). Capillary fluid absorption from extra- to intravascular space was reduced by ∼40% in VVS women (P < 0.05). Accordingly, the reduction in cardiac output was more pronounced (P < 0.05). In conclusion, in VVS women, mobilization of peripheral venous blood and net fluid absorption from tissue to blood during hypovolemic stress were decreased partly as a result of an attenuated vasoconstrictor response. This may seriously impede maintenance of cardiac output during hypovolemic stress and could contribute to the pathogenesis of VVS.

  4. Residual limb volume change: Systematic review of measurement and management

    Directory of Open Access Journals (Sweden)

    Joan E. Sanders, PhD

    2011-10-01

    Full Text Available Management of residual limb volume affects decisions regarding timing of fit of the first prosthesis, when a new prosthetic socket is needed, design of a prosthetic socket, and prescription of accommodation strategies for daily volume fluctuations. This systematic review assesses what is known about measurement and management of residual limb volume change in persons with lower-limb amputation. Publications that met inclusion criteria were grouped into three categories: group I: descriptions of residual limb volume measurement techniques; group II: studies investigating the effect of residual limb volume change on clinical care in people with lower-limb amputation; and group III: studies of residual limb volume management techniques or descriptions of techniques for accommodating or controlling residual limb volume. We found that many techniques for the measurement of residual limb volume have been described but clinical use is limited largely because current techniques lack adequate resolution and in-socket measurement capability. Overall, limited evidence exists regarding the management of residual limb volume, and the evidence available focuses primarily on adults with transtibial amputation in the early postoperative phase. While we can draw some insights from the available research about residual limb volume measurement and management, further research is required.

  5. Volume-dependent hemodynamic effects of blood collection in canine donors - evaluation of 13% and 15% of total blood volume depletion

    Directory of Open Access Journals (Sweden)

    RUI R.F. FERREIRA

    2015-03-01

    Full Text Available Background: There is no consensus regarding the blood volume that could be safely donated by dogs, ranging from 11 to 25% of its total blood volume (TBV. No previous studies evaluated sedated donors.Aim: To evaluate the hemodynamic effects of blood collection from sedated and non-sedated dogs and to understand if such effects were volume-dependent.Materials and Methods: Fifty three donations of 13% of TBV and 20 donations of 15% TBV were performed in dogs sedated with diazepam and ketamine. Additionally, a total of 30 collections of 13% TBV and 20 collections of 15% TBV were performed in non-sedated dogs. Non-invasive arterial blood pressures and pulse rates were registered before and 15 min after donation. Results: Post-donation pulse rates increased significantly in both sedated groups, with higher differences in the 15% TBV collections. Systolic arterial pressures decreased significantly in these groups, while diastolic pressures increased significantly in 13% TBV donations. Non-sedated groups revealed a slight, but significant, SBP decrease. No clinical signs related to donations were registered.Conclusion: These results suggest that the collection of 15% TBV in sedated donors induces hemodynamic variations that may compromise the harmlessness of the procedure, while it seems to be a safe procedure in non-sedated dogs.

  6. Ambulatory instrument for monitoring indirect beat-to-beat blood pressure in superficial temporal artery using volume-compensation method.

    Science.gov (United States)

    Tanaka, S; Yamakoshi, K

    1996-11-01

    A portable instrument, based on a volume-compensation technique, is designed for ambulatory monitoring of indirect beat-to-beat blood pressure (BP) in the superficial temporal artery. The instrument consists of a small disc-type cuff and a portable unit carried by the subject. Several components are integrated in the cuff for applying counter-pressure to the artery, i.e. a reflectance-type photo-plethysmographic sensor for arterial volume detection, a pressure sensor for cuff pressure Pc measurement and a nozzle flapper-type- electro-pneumatic convertor for controlling Pc. The portable unit includes volume servo control circuitry and a microprocessor-based signal-processing and recording unit. This automatically performs all the necessary measurement procedures and stores into a memory IC element the processed systolic, mean and diastolic blood pressure data, together with pulse intervals on a beat-to-beat basis from the servo-controlled Pc (indirectly measured BP waveform). With this instrument, momentary changes in BP during ambulatory situations such as bicycle ergometer exercise and daily activities including motorway driving are successfully recorded. From the results of simultaneous measurement of the subject's posture changes, the effect of posture change on blood pressure, e.g. baroreceptor-cardiac reflex, is also clearly demonstrated.

  7. Sleep apnea termination decreases cerebral blood volume: a near-infrared spectroscopy case study

    Science.gov (United States)

    Virtanen, Jaakko; Noponen, Tommi; Salmi, Tapani; Toppila, Jussi; Meriläinen, Pekka

    2009-07-01

    Medical near-infrared spectroscopy (NIRS) can be used to estimate cerebral haemodynamic changes non-invasively. Sleep apnea is a common sleep disorder where repetitive pauses in breathing decrease the quality of sleep and exposes the individual to various health problems. We have measured oxygenated and deoxygenated haemoglobin concentration changes during apneic events in sleep from the forehead of one subject using NIRS and used principal component analysis to extract extracerebral and cortical haemodynamic changes from NIRS signals. Comparison of NIRS signals with EEG, bioimpedance, and pulse oximetry data suggests that termination of apnea leads to decreases in cerebral blood volume and flow that may be related to neurological arousal via neurovascular coupling.

  8. Reduced defense of central blood volume during acute lower body negative pressure-induced hypovolemic circulatory stress in aging women.

    Science.gov (United States)

    Lindenberger, Marcus; Länne, Toste

    2012-06-01

    Elderly humans are more vulnerable to trauma and hemorrhage than young and elderly men and respond with decreased defense of central blood volume during acute experimental hypovolemia induced by lower body negative pressure (LBNP). However, these defense mechanisms have not been evaluated in elderly women. The aim of this study was to determine the effectiveness of compensatory responses to defend central blood volume during experimental hypovolemia in elderly and young women. Cardiovascular responses in 34 women, 12 elderly (66 ± 1 years) and 22 young women (23 ± 0.4 years), were studied during experimental hypovolemia induced by LBNP of 11 to 44 mmHg. Air plethysmography was used to assess the capacitance response (redistribution of peripheral venous blood to the central circulation) as well as net capillary fluid transfer from tissue to blood in the arm. Lower body negative pressure seemed to create comparable hypovolemia measured as total calf volume increase in elderly and young women. Heart rate increased less in elderly women (LBNP of 44 mmHg: 20 ± 2 vs. 37 ± 4%; P < 0.01) but with similar (%) increase in forearm vascular resistance. Mobilization of capacitance blood from the peripheral circulation was both slower and decreased by ∼60% in elderly women (P < 0.001), and net capillary fluid absorption from surrounding tissues was reduced by ∼40% (P < 0.01, LBNP of 44 mmHg). Elderly women responded with less increase in heart rate but with equal forearm vascular resistance (%) response during LBNP. Furthermore, the compensatory capacitance response was both slower and substantially decreased, and net capillary fluid absorption considerably reduced, collectively indicating less efficiency to defend central blood volume in elderly than in young women.

  9. A blood pressure measurement method based on synergetics theory

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>The principle for blood pressure measurement using pulse transit time is introduced in this paper.And the math model of synergetics theory is studied in detail.The synergetics theory is applied in the analysis of blood pressure measurement data.The simulation results show that the application of synergetics theory is helpful to judge the normal blood pressure,and the accuracy is up to 80%.

  10. Central administration of kisspeptin-10 inhibits natriuresis and diuresis induced by blood volume expansion in anesthetized male rats

    OpenAIRE

    Han, Xu; Yan, Ming; An, Xiao-fei; HE Ming; Yu, Jiang-Yi

    2009-01-01

    Aim: To investigate the possible role of hypothalamic kisspeptin in the regulation of body fluid metabolism and maintenance of internal homeostasis. Methods: Natriuresis and diuresis were induced by blood volume expansion (VE) in anesthetized male rats and kisspeptin-10 was intracerebroventricularly (icv) administered. Radioimmunoassay (RIA) was used to measure the plasma arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) concentrations during the VE. The mediation of the renal s...

  11. 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.

  12. Loss of alveolar membrane diffusing capacity and pulmonary capillary blood volume in pulmonary arterial hypertension

    Science.gov (United States)

    2013-01-01

    Background Reduced gas transfer in patients with pulmonary arterial hypertension (PAH) is traditionally attributed to remodeling and progressive loss of pulmonary arterial vasculature that results in decreased capillary blood volume available for gas exchange. Methods We tested this hypothesis by determination of lung diffusing capacity (DL) and its components, the alveolar capillary membrane diffusing capacity (Dm) and lung capillary blood volume (Vc) in 28 individuals with PAH in comparison to 41 healthy individuals, and in 19 PAH patients over time. Using single breath simultaneous measure of diffusion of carbon monoxide (DLCO) and nitric oxide (DLNO), DL and Dm were respectively determined, and Vc calculated. Dm and Vc were evaluated over time in relation to standard clinical indicators of disease severity, including brain natriuretic peptide (BNP), 6-minute walk distance (6MWD) and right ventricular systolic pressure (RVSP) by echocardiography. Results Both DLCO and DLNO were reduced in PAH as compared to controls and the lower DL in PAH was due to loss of both Dm and Vc (all p DLNO decreased by 24 ml/min/mmHg/year (p = 0.01). Consequently, Dm decreased and Vc tended to increase over time, which led to deterioration of the Dm/Vc ratio, a measure of alveolar-capillary membrane functional efficiency without changes in clinical markers. Conclusions The findings indicate that lower than normal gas transfer in PAH is due to loss of both Dm and Vc, but that deterioration of Dm/Vc over time is related to worsening membrane diffusion. PMID:23339456

  13. Comparison of pathogen DNA isolation methods from large volumes of whole blood to improve molecular diagnosis of bloodstream infections.

    Directory of Open Access Journals (Sweden)

    Anne J M Loonen

    Full Text Available For patients suffering from bloodstream infections (BSI molecular diagnostics from whole blood holds promise to provide fast and adequate treatment. However, this approach is hampered by the need of large blood volumes. Three methods for pathogen DNA isolation from whole blood were compared, i.e. an enzymatic method (MolYsis, 1-5 ml, the novel non-enzymatic procedure (Polaris, 1-5 ml, and a method that does not entail removal of human DNA (Triton-Tris-EDTA EasyMAG, 200 µl. These methods were evaluated by processing blood spiked with 0-1000 CFU/ml of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. Downstream detection was performed with real-time PCR assays. Polaris and MolYsis processing followed by real-time PCRs enabled pathogen detection at clinically relevant concentrations of 1-10 CFU/ml blood. By increasing sample volumes, concurrent lower cycle threshold (Ct values were obtained at clinically relevant pathogen concentrations, demonstrating the benefit of using larger blood volumes. A 100% detection rate at a concentration of 10 CFU/ml for all tested pathogens was obtained with the Polaris enrichment, whereas comparatively lower detection rates were measured for MolYsis (50-67% and EasyMAG (58-79%. For the samples with a concentration of 1 CFU/ml Polaris resulted in most optimal detection rates of 70-75% (MolYsis 17-50% and TTE-EasyMAG 20-36%. The Polaris method was more reproducible, less labour intensive, and faster (45 minutes (including Qiagen DNA extraction vs. 2 hours (MolYsis. In conclusion, Polaris and MolYsis enrichment followed by DNA isolation and real-time PCR enables reliable and sensitive detection of bacteria and fungi from 5 ml blood. With Polaris results are available within 3 hours, showing potential for improved BSI diagnostics.

  14. Pulmonary blood volume and transit time in cirrhosis: relation to lung function

    DEFF Research Database (Denmark)

    Møller, Søren; Burchardt, H; Øgard, CG

    2006-01-01

    BACKGROUND/AIMS: In cirrhosis a systemic vasodilatation leads to an abnormal distribution of the blood volume with a contracted central blood volume. In addition, the patients have a ventilation/perfusion imbalance with a low diffusing capacity. As the size of the pulmonary blood volume (PBV) has...... not been determined separately we assessed PBV and pulmonary transit time (PTT) in relation to lung function in patients with cirrhosis and in controls. METHODS: Pulmonary and cardiac haemodynamics and transit times were determined by radionuclide techniques in 22 patients with alcoholic cirrhosis...... and in 12 controls. The lung function including diffusing capacity for carbon monoxide (DL, CO) was determined by conventional single breath technique. RESULTS: In the patients, PTT was shorter, 3.9+/-1.2 vs 5.7+/-1.0 s in the controls, P

  15. Pulmonary blood volume and transit time in cirrhosis: relation to lung function

    DEFF Research Database (Denmark)

    Møller, Søren; Burchardt, H; Øgard, CG;

    2006-01-01

    not been determined separately we assessed PBV and pulmonary transit time (PTT) in relation to lung function in patients with cirrhosis and in controls. METHODS: Pulmonary and cardiac haemodynamics and transit times were determined by radionuclide techniques in 22 patients with alcoholic cirrhosis......BACKGROUND/AIMS: In cirrhosis a systemic vasodilatation leads to an abnormal distribution of the blood volume with a contracted central blood volume. In addition, the patients have a ventilation/perfusion imbalance with a low diffusing capacity. As the size of the pulmonary blood volume (PBV) has...... and in 12 controls. The lung function including diffusing capacity for carbon monoxide (DL, CO) was determined by conventional single breath technique. RESULTS: In the patients, PTT was shorter, 3.9+/-1.2 vs 5.7+/-1.0 s in the controls, P

  16. Near-infrared spectroscopy measurement of blood oxygenation content and its application in sports practice

    Science.gov (United States)

    Xu, Guodong; Gong, Hui; Ge, Xinfa; Luo, Qingming

    2003-12-01

    To research the change characteristics of blood oxygenation content in skeletal muscle, the change regularity between blood oxygenation content and exercise intensity as well as HbO2 and blood lactate acid while taking incremental exercises, we took an in vivo, real-time and continuous measurement on the blood oxygenation content of eight sportsmen when they did incremental exercises of five degrees on a power bicycle using a portable tissue oximeter which is based on the principle of near-infrared spectroscopy(NIRS), simultaneously, we detected the blood lactate acid of subjects after each degree of incremental physical load instantly using a blood lactate analysis equipment. The results showed that the content of HbO2 descended regularly while that of Hb ascended; blood volume decreased; and the density of lactate increased as the intensity of exercises was heightened. The statistics analyses showed that the relationship between HbO2 and blood lactate is rather close (correlation coefficient r=-0.918). With this discovery, a theoretical basis in measuring the relative change of blood oxygenation content non-invasively was evidenced, and a novel technology for assessing the physical situation of sportsman, grasping sports density and evaluating the training effect could be imported.

  17. Limitations of stroke volume estimation by non-invasive blood pressure monitoring in hypergravity.

    Directory of Open Access Journals (Sweden)

    Olivier Manen

    Full Text Available Altitude and gravity changes during aeromedical evacuations induce exacerbated cardiovascular responses in unstable patients. Non-invasive cardiac output monitoring is difficult to perform in this environment with limited access to the patient. We evaluated the feasibility and accuracy of stroke volume estimation by finger photoplethysmography (SVp in hypergravity.Finger arterial blood pressure (ABP waveforms were recorded continuously in ten healthy subjects before, during and after exposure to +Gz accelerations in a human centrifuge. The protocol consisted of a 2-min and 8-min exposure up to +4 Gz. SVp was computed from ABP using Liljestrand, systolic area, and Windkessel algorithms, and compared with reference values measured by echocardiography (SVe before and after the centrifuge runs.The ABP signal could be used in 83.3% of cases. After calibration with echocardiography, SVp changes did not differ from SVe and values were linearly correlated (p<0.001. The three algorithms gave comparable SVp. Reproducibility between SVp and SVe was the best with the systolic area algorithm (limits of agreement -20.5 and +38.3 ml.Non-invasive ABP photoplethysmographic monitoring is an interesting technique to estimate relative stroke volume changes in moderate and sustained hypergravity. This method may aid physicians for aeronautic patient monitoring.

  18. Translation Invariant Extensions of Finite Volume Measures

    Science.gov (United States)

    Goldstein, S.; Kuna, T.; Lebowitz, J. L.; Speer, E. R.

    2017-02-01

    We investigate the following questions: Given a measure μ _Λ on configurations on a subset Λ of a lattice L, where a configuration is an element of Ω ^Λ for some fixed set Ω , does there exist a measure μ on configurations on all of L, invariant under some specified symmetry group of L, such that μ _Λ is its marginal on configurations on Λ ? When the answer is yes, what are the properties, e.g., the entropies, of such measures? Our primary focus is the case in which L=Z^d and the symmetries are the translations. For the case in which Λ is an interval in Z we give a simple necessary and sufficient condition, local translation invariance ( LTI), for extendibility. For LTI measures we construct extensions having maximal entropy, which we show are Gibbs measures; this construction extends to the case in which L is the Bethe lattice. On Z we also consider extensions supported on periodic configurations, which are analyzed using de Bruijn graphs and which include the extensions with minimal entropy. When Λ subset Z is not an interval, or when Λ subset Z^d with d>1, the LTI condition is necessary but not sufficient for extendibility. For Z^d with d>1, extendibility is in some sense undecidable.

  19. Translation Invariant Extensions of Finite Volume Measures

    Science.gov (United States)

    Goldstein, S.; Kuna, T.; Lebowitz, J. L.; Speer, E. R.

    2016-08-01

    We investigate the following questions: Given a measure μ _Λ on configurations on a subset Λ of a lattice L, where a configuration is an element of Ω ^Λ for some fixed set Ω , does there exist a measure μ on configurations on all of L, invariant under some specified symmetry group of L, such that μ _Λ is its marginal on configurations on Λ ? When the answer is yes, what are the properties, e.g., the entropies, of such measures? Our primary focus is the case in which L=Z^d and the symmetries are the translations. For the case in which Λ is an interval in Z we give a simple necessary and sufficient condition, local translation invariance (LTI), for extendibility. For LTI measures we construct extensions having maximal entropy, which we show are Gibbs measures; this construction extends to the case in which L is the Bethe lattice. On Z we also consider extensions supported on periodic configurations, which are analyzed using de Bruijn graphs and which include the extensions with minimal entropy. When Λ subset Z is not an interval, or when Λ subset Z^d with d>1 , the LTI condition is necessary but not sufficient for extendibility. For Z^d with d>1 , extendibility is in some sense undecidable.

  20. 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....../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......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...

  1. 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 knee art

  2. 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.

  3. Effect of volume loading on the Frank-Starling relation during reductions in central blood volume in heat-stressed humans

    DEFF Research Database (Denmark)

    Bundgaard-Nielsen, Morten; Wilson, T E; Seifert, Thomas

    2010-01-01

    During reductions in central blood volume while heat stressed, a greater decrease in stroke volume (SV) for a similar decrease in ventricular filling pressure, compared to normothermia, suggests that the heart is operating on a steeper portion of a Frank-Starling curve. If so, volume loading of h...

  4. A time-of-flight flow sensor for the volume measurement of trace amount of interstitial fluid

    Science.gov (United States)

    Yu, H.; Li, D.; Roberts, R. C.; Xu, K.; Tien, N. C.

    2012-05-01

    Transdermal extraction of interstitial fluid (ISF) offers an attractive method for noninvasive blood glucose monitoring. The existing macroscale systems are not suitable for ISF collection, mainly because of the minute volume of the transdermally extracted ISF which scatters on the skin surface. Human skin's low permeability to glucose and its varying permeability exemplify the crucial need to make precise ISF volume measurements in order to calculate blood glucose concentrations accurately. In this paper, we present a novel time-of-flight flow sensor consisting of four electrode pairs fabricated directly into the channel of a polydimethylsiloxane (PDMS) microfluidic device designed to accurately measure the volume of transdermally extracted ISF. As fluid traverses the channel, it bridges each electrode pair and changes its resistance. By measuring the time difference in resistance change between each electrode pair, a precise fluid volume can be measured. In order to verify the suitability of the sensor for biological applications, experiments were conducted using a normal saline solution which is similar to ISF. The stability of the sensor was tested using a fixed volume, and the coefficient of variation for 20 tests was determined to be 0.0041. The consistency of the sensor for varied volume measurements was shown by the high correlation coefficient (R2 = 0.9992) between the tested volume and the volume measured by a commercial micro syringe. The excellent functionality of the flow sensor can be extended toward the measurement of conductive chemical and biochemical buffers and reagents.

  5. Imaging changes in blood volume and oxygenation in the newborn infant brain using three-dimensional optical tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hebden, Jeremy C [Department of Medical Physics and Bioengineering, University College London, 11-20 Capper Street, London WC1E 6JA (United Kingdom); Gibson, Adam [Department of Medical Physics and Bioengineering, University College London, 11-20 Capper Street, London WC1E 6JA (United Kingdom); Austin, Topun [Department of Paediatrics and Child Health, University College London, 5 University Street, London WC1E 6JJ (United Kingdom); Yusof, Rozarina Md [Department of Medical Physics and Bioengineering, University College London, 11-20 Capper Street, London WC1E 6JA (United Kingdom); Everdell, Nick [Department of Medical Physics and Bioengineering, University College London, 11-20 Capper Street, London WC1E 6JA (United Kingdom); Delpy, David T [Department of Medical Physics and Bioengineering, University College London, 11-20 Capper Street, London WC1E 6JA (United Kingdom); Arridge, Simon R [Department of Computer Science, University College London, Gower Street, London WC1E 6BT (United Kingdom); Meek, Judith H [Department of Paediatrics and Child Health, University College London, 5 University Street, London WC1E 6JJ (United Kingdom); Wyatt, John S [Department of Paediatrics and Child Health, University College London, 5 University Street, London WC1E 6JJ (United Kingdom)

    2004-04-07

    Induced haemodynamic and blood oxygenation changes occurring within the brain of a ventilated newborn infant have been imaged in three dimensions using optical tomography. Noninvasive measurements of the flight times of transmitted light were acquired during illumination of the brain by laser pulses at wavelengths of 780 nm and 815 nm. The oxygen and carbon dioxide partial pressures were adjusted through alterations to the ventilator settings, resulting in changes to the cerebral blood volume and oxygenation. Three-dimensional images were generated using the physiologically associated differences in the measured data, obviating the need for data calibration using a separate reference measurement. The results exhibit large changes in absorption coefficient at both wavelengths. Images corresponding to differences in concentrations of oxy- and deoxyhaemoglobin are in qualitative agreement with known physiological data.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-15

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

  7. Micro-PIV measurements of blood flow in extraembryonic blood vessels of chicken embryos.

    Science.gov (United States)

    Lee, Jung Yeop; Ji, Ho Seong; Lee, Sang Joon

    2007-10-01

    The hemodynamic characteristics of blood flow are important in the diagnosis of circulatory diseases, since such diseases are related to wall shear stress of cardiovascular vessels. In chicken embryos at early stages of development, it is possible to directly visualize blood flow inside blood vessels. We therefore employed a micro-PIV technique to assess blood flow in extraembryonic venous and arterial blood vessels of chicken embryos, using red blood cells (RBCs) as tracers and obtaining flow images of RBCs using a high-speed CMOS camera. The mean velocity field showed non-Newtonian flow characteristics. The blood flow in two venous vessels merged smoothly into the Y-shaped downstream vein without any flow separation or secondary flow. Vorticity was high in the inner regions, where the radius of curvature varied greatly. A periodic variation of temporally resolved velocity signals, due to beating of the heart, was observed in arterial blood vessels. The pulsating frequency was obtained by fast Fourier transform analysis using the measured velocity data. The measurement technique used here was useful in analyzing the hemodynamic characteristics of in vivo blood flow in chicken embryos.

  8. Detection and measurement of retinal blood vessel pulsatile motion

    Science.gov (United States)

    Xiao, Di; Frost, Shaun; Vignarajan, Janardhan; An, Dong; Tay-Kearney, Mei-Ling; Kanagasingam, Yogi

    2016-03-01

    Retinal photography is a non-invasive and well-accepted clinical diagnosis of ocular diseases. Qualitative and quantitative assessment of retinal images is crucial in ocular diseases related clinical application. Pulsatile properties caused by cardiac rhythm, such as spontaneous venous pulsation (SVP) and pulsatile motion of small arterioles, can be visualized by dynamic retinal imaging techniques and provide clinical significance. In this paper, we aim at vessel pulsatile motion detection and measurement. We proposed a novel approach for pulsatile motion measurement of retinal blood vessels by applying retinal image registration, blood vessel detection and blood vessel motion detection and measurement on infrared retinal image sequences. The performance of the proposed methods was evaluated on 8 image sequences with 240 images. A preliminary result has demonstrated the good performance of the method for blood vessel pulsatile motion observation and measurement.

  9. Effect of blood donation-mediated volume reduction on regional right ventricular deformation in healthy subjects.

    Science.gov (United States)

    Açar, Göksel; Alizade, Elnur; Avci, Anıl; Cakir, Hakan; Efe, Suleyman Cagan; Kalkan, Mehmet Emin; Tabakci, Mehmet Mustafa; Toprak, Cuneyt; Tanboğa, Ibrahim Halil; Esen, Ali Metin

    2014-03-01

    Strain (S) and strain rate (SR) are known to be altered in diseases associated with right ventricular (RV) pressure/volume overload and RV myocardial dysfunction; however determinants of S/SR are incompletely understood. The aim of this study was to examine the effect of blood donation-mediated volume reduction on regional RV deformation in healthy young adults. Study population was composed of 61 consecutive healthy subjects who were volunteers for blood donation. All underwent standard echocardiography and two-dimensional S and SR imaging by speckle tracking before and after 450 mL blood donation. We found no change in RV lateral wall SR in all three segments. However, the S in the apical and mid segments of the RV lateral wall immediately decreased after blood donation [-26.2 ± 3.3 vs. -23.2 ± 3.3 % (p subjects caused a regional difference in RV longitudinal deformation with the lower mid and apical S that was related to parameters of volume load severity. However, RV systolic SR was found to be resistant to the effects of volume depletion.

  10. Analysis of Partial Volume Effects on Accurate Measurement of the Hippocampus Volume

    Institute of Scientific and Technical Information of China (English)

    Maryam Hajiesmaeili; Jamshid Dehmeshki; Tim Ellis

    2014-01-01

    Hippocampal volume loss is an important biomarker in distinguishing subjects with Alzheimer’s disease (AD) and its measurement in magnetic resonance images (MRI) is influenced by partial volume effects (PVE). This paper describes a post-processing approach to quantify PVE for correction of the hippocampal volume by using a spatial fuzzyC-means (SFCM) method. The algorithm is evaluated on a dataset of 20 T1-weighted MRI scans sampled at two different resolutions. The corrected volumes for left and right hippocampus (HC) which are 23% and 18% for the low resolution and 6% and 5% for the high resolution datasets, respectively are lower than hippocampal volume results from manual segmentation. Results show the importance of applying this technique in AD detection with low resolution datasets.

  11. Measuring industrial energy efficiency: Physical volume versus economic value

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, S.L.; Niefer, M.J.; Roop, J.M.

    1996-12-01

    This report examines several different measures of industrial output for use in constructing estimates of industrial energy efficiency and discusses some reasons for differences between the measures. Estimates of volume-based measures of output, as well as 3 value-based measures of output (value of production, value of shipments, and value added), are evaluated for 15 separate 4-digit industries. Volatility, simple growth rate, and trend growth rate estimates are made for each industry and each measure of output. Correlations are made between the volume- and value-based measures of output. Historical energy use data are collected for 5 of the industries for making energy- intensity estimates. Growth rates in energy use, energy intensity, and correlations between volume- and value-based measures of energy intensity are computed. There is large variability in growth trend estimates both long term and from year to year. While there is a high correlation between volume- and value-based measures of output for a few industries, typically the correlation is low, and this is exacerbated for estimates of energy intensity. Analysis revealed reasons for these low correlations. It appears that substantial work must be done before reliable measures of trends in the energy efficiency of industry can be accurately characterized.

  12. Effect of volume loading on the Frank-Starling relation during reductions in central blood volume in heat-stressed humans

    DEFF Research Database (Denmark)

    Bundgaard-Nielsen, Morten; Wilson, T E; Seifert, Thomas;

    2010-01-01

    from whom pulmonary capillary wedge pressure (PCWP), central venous pressure and SV (via thermodilution) were obtained while central blood volume was reduced via lower-body negative pressure (LBNP) during normothermia, whole-body heating (increase in blood temperature 1 degrees C), and during whole......During reductions in central blood volume while heat stressed, a greater decrease in stroke volume (SV) for a similar decrease in ventricular filling pressure, compared to normothermia, suggests that the heart is operating on a steeper portion of a Frank-Starling curve. If so, volume loading...... of heat-stressed individuals would shift the operating point to a flatter portion of the heat stress Frank-Starling curve thereby attenuating the reduction in SV during subsequent decreases in central blood volume. To investigate this hypothesis, right heart catheterization was performed in eight males...

  13. A STUDY ON MORPHOMETRIC MEASUREMENT OF VOLUME OF ACETABULUM

    Directory of Open Access Journals (Sweden)

    Leena Khobragade,

    2014-09-01

    Full Text Available Background: Hip joint represents an unique functional unit and has complex biomechanical construction. In today’s era where total hip replacement surgeries have made their way it has become imperative for the anatomists to know the variations in acetabular dimensions. Reconstruction of acetabulum in patients with significant acetabular bone deficiency remains a challenge. Hence the present study was carried out with the aim to study the morphometric measurement of volume of acetabulum in both the sexes. Materials and Methods: Material of the study consisted of 110 human hip bones (60 males and 50 females. Volume of Acetabulum (VA was measured on these hip bones on both the sides. Statistical analysis was done using SPSS (Statistical Package for the Social Sciences version 11 and Microsoft Excel 2007. Results: The mean volume of acetabulum in male was 23.13 ml and female was 17.88 ml. The mean volume of acetabulum on right side was 20.55 ml and left side was 20.91 ml. Volume of the acetabulum was greater in males as compared to females and the differences were statistically significant. Volume was greater on the left side as compared to the right side but the difference was statistically non significant. Discussion: Analysing the differences on human acetabulum is helpful in understanding not only morphological but also medicolegal aspects. Conclusion: Volume of the acetabulum was greater in males as compared to females.

  14. On-line Measuring Method for Shell Chamber Volume

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-zhong; WANG De-min; JIANG Tao; CAO Guo-hua; WANG Qi

    2005-01-01

    Using the ideal gas state equation, an on-line measuring method for the shell chamber volume is studied in this paper. After analyzing how various measurement parameters affect the measurement accuracy, the system parameters are optimized in this method. Because the shape and volume of the tested items are similar, the method of using "tamping" to raise the accuracy and speed of the measurement is put forward. Based on the work above, a prototype of the testing instrument for shell chamber volume was developed, automatically testing and controlling. Compared with the method of "water weight", this method is more accurate, quicker and more automotive, so it is adaptable for the use of on-line detection.

  15. Method for measuring anterior chamber volume by image analysis

    Science.gov (United States)

    Zhai, Gaoshou; Zhang, Junhong; Wang, Ruichang; Wang, Bingsong; Wang, Ningli

    2007-12-01

    Anterior chamber volume (ACV) is very important for an oculist to make rational pathological diagnosis as to patients who have some optic diseases such as glaucoma and etc., yet it is always difficult to be measured accurately. In this paper, a method is devised to measure anterior chamber volumes based on JPEG-formatted image files that have been transformed from medical images using the anterior-chamber optical coherence tomographer (AC-OCT) and corresponding image-processing software. The corresponding algorithms for image analysis and ACV calculation are implemented in VC++ and a series of anterior chamber images of typical patients are analyzed, while anterior chamber volumes are calculated and are verified that they are in accord with clinical observation. It shows that the measurement method is effective and feasible and it has potential to improve accuracy of ACV calculation. Meanwhile, some measures should be taken to simplify the handcraft preprocess working as to images.

  16. Micro analysis of fringe field formed inside LDA measuring volume

    Science.gov (United States)

    Ghosh, Abhijit; Nirala, A. K.

    2016-05-01

    In the present study we propose a technique for micro analysis of fringe field formed inside laser Doppler anemometry (LDA) measuring volume. Detailed knowledge of the fringe field obtained by this technique allows beam quality, alignment and fringe uniformity to be evaluated with greater precision and may be helpful for selection of an appropriate optical element for LDA system operation. A complete characterization of fringes formed at the measurement volume using conventional, as well as holographic optical elements, is presented. Results indicate the qualitative, as well as quantitative, improvement of fringes formed at the measurement volume by holographic optical elements. Hence, use of holographic optical elements in LDA systems may be advantageous for improving accuracy in the measurement.

  17. Volume Measurement in Solid Objects Using Artificial Vision Technique

    Science.gov (United States)

    Cordova-Fraga, T.; Martinez-Espinosa, J. C.; Bernal, J.; Huerta-Franco, R.; Sosa-Aquino, M.; Vargas-Luna, M.

    2004-09-01

    A simple system using artificial vision technique for measuring the volume of solid objects is described. The system is based on the acquisition of an image sequence of the object while it is rotating on an automated mechanism controlled by a PC. Volumes of different objects such as a sphere, a cylinder and also a carrot were measured. The proposed algorithm was developed in environment LabView 6.1. This technique can be very useful when it is applied to measure the human body for evaluating its body composition.

  18. A liquid-independent volume flow measurement principle

    NARCIS (Netherlands)

    Geers, L.F.G.; Volker, A.W.F.; Hunter, T.P.M.

    2010-01-01

    A novel flow measurement principle is presented enabling non-intrusive volume flow measurements of liquids in the ml/min range. It is based on an opto-acoustical time-of-flight principle, where the time interval is recorded in which a thermal label travels a known distance through a flow channel. Bi

  19. Finding the Density of Objects without Measuring Mass and Volume

    Science.gov (United States)

    Mumba, Frackson; Tsige, Mesfin

    2007-01-01

    A simple method based on the moment of forces and Archimedes' principle is described for finding density without measuring the mass and volume of an object. The method involves balancing two unknown objects of masses M[subscript 1] and M[subscript 2] on each side of a pivot on a metre rule and measuring their corresponding moment arms. The object…

  20. Measurement and Comparison of Organic Compound Concentrations in Plasma, Whole Blood, and Dried Blood Spot Samples.

    Science.gov (United States)

    Batterman, Stuart A; Chernyak, Sergey; Su, Feng-Chiao

    2016-01-01

    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 (R (2) > 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

  1. 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

  2. Estimated central blood volume in cirrhosis: relationship to sympathetic nervous activity, beta-adrenergic blockade and atrial natriuretic factor

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Bendtsen, Flemming; Gerbes, A L

    1992-01-01

    The estimated central blood volume (i.e., blood volume in the heart cavities, lungs and central arterial tree) was determined by multiplying cardiac output by circulatory mean transit time in 19 patients with cirrhosis and compared with sympathetic nervous activity and circulating level of atrial...

  3. BLOOD-VOLUME AND BODY-FLUID COMPARTMENTS IN LAMBS WITH AORTOPULMONARY LEFT-TO-RIGHT SHUNTS

    NARCIS (Netherlands)

    GRATAMA, JWC; DALINGHAUS, M; MEUZELAAR, JJ; GERDING, AM; KOERS, JH; ZIJLSTRA, WG; KUIPERS, JRG

    1992-01-01

    A left-to-right shunt is accompanied by an increased plasma and blood volume. Since this is likely realized through renin/aldosterone-mediated salt and water retention, other body fluid compartments may be changed too. Therefore, we studied blood volume and body fluid compartments by a single-inject

  4. Effects of CO2 pneumoperitoneum on blood flow vol-ume of abdominal organs of rabbits with controlled hem-orrhagic shock and liver impact injuries

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lian-yang; ZHAO Song; LI Yong; MA Xiao-lin

    2009-01-01

    Objective: To investigate the effects of CO2 pneumo-peritoneum on blood flow volume of abdominal organs of rabbits with controlled hemorrhagic shock model and liver impact injuries.Methods: After controlled hemorrhagic shock and liver impact injuries, the rabbit model was established. Eighteen rabbits subjected to hemorrhagic shock and liver impact inju-ries were divided into 3 groups randomly according to the volume of lost blood: light hemorrhagic shock (blood loss volume was 10%, 6 ml/kg), moderate hemorrhagic shock (20%, 12 ml/kg) and severe hemorrhagic shock (40%, 22 ml/kg). Intraabdominal pressures of CO2 pneumoperitoneum was 10 mmHg. Color-labeled microspheres were used to mea-sure the blood flow volume of the liver, kidney and stomach before pneumoperitoneum at 30 minutes and 2 hours after pneumoperitoneum and 30 minutes after deflation. And the mortality and hepatic traumatic condition of rabbits were recorded.Results: Of the 18 rabbits, there were 9 with liver impact injuries at Grade Ⅰ, 8 at Grade Ⅱ and Ⅰ at Grade Ⅲ (according to AIS-2005). The mortality rate in light hemorrhagic shock group was 33.33%, and that in moderate or severe hemor-rhagic shock group was 100% within 30 minutes and 2 hours after pneumoperitoneum, respectively. The blood flow vol-ume in the organs detected decreased at 30 minutes under pneumoperitoneum in light and moderate hemorrhagic shock groups. At the same time, the blood flow volume of the liver in moderate hemorrhagic shock group decreased more sig-nificantly than that in light hemorrhagic shock group.Conclusions: The blood flow volume of abdominal organs in rabbits is decreased obviously under CO2 pneumoperitoneum, with fairly high mortality rate. It is be-lieved that CO2 pneumoperitoneum should cautiously be used in abdominal injury accompanied with hemorrhagic shock, especially under non-resuscitation conditions.

  5. Measurement and Hemodialysis Effect of Complex Relative Permittivity for Blood of Kidney Patients Using Open-Ended Coaxial Measurement Probe

    Science.gov (United States)

    Takeda, Akira; Takata, Kazuyuki; Nagao, Hirotomo; Wang, Jianqing; Fujiwara, Osamu

    Before evaluating the quality of hemodialysis from the limited volume of human blood using a commercially available open-ended coaxial probe, we previously measured the complex relative permittivity of pure water from 200 MHz to 6 GHz with respect to its measured liquid volume, and revealed that 1.9 ml water in a beaker with a diameter of 24 mm and a depth of 2 mm gives a variation within ±0.5 % for the real part and ±7 % for the imaginary part. Based on the above finding, we measured the dielectric properties of 2.5 ml whole blood at 25°C for 10 normal healthy subjects and 9 hemodialysis patients. The measured results on healthy subjects show good agreement with the data reported by Gabriel for human blood at 37°C, while they provide different dispersion characteristics of straight lines for their Cole-Cole plots. The measured results on the patients give further different dispersion characteristics in comparison with the healthy subjects. In order to investigate the above differences statistically, the student t-test was conducted to reveal that permittivity at infinite frequency for the Cole-Cole plots is significantly different with a level of 1 % among its averaged values for normal healthy subjects and patients before dialysis.

  6. Fluid-filled blood pressure measurement systems.

    Science.gov (United States)

    Li, J K; van Brummelen, A G; Noordergraaf, A

    1976-05-01

    The performance of catheter-manometer systems for the measurement of pulsatile pressure has been evaluated by both experimental techniques and theoretical considerations. The former approach has shown, on occasion, multiple maxima in the amplitude response. The latter has been approached in a variety of ways, ranging from extreme lumping to application of transmission line theory while employing different configurations in the system's representation. Multiple maxima have also been seen, The present paper identifies the sources of the differences found and compares the relative merits of various theoretical approaches. It introduces the compliance of the system as a figure of merit and provides a simple first-order approximation formula for evaluation of the quality of a system. Damping and impedance matching to improve the system's frequency response were studied. It was found that they were not needed in a very stiff or a very compliant system, nor should one worry about the representation of such a system.

  7. Muscular adaptations after two different volumes of blood flow-restricted training.

    Science.gov (United States)

    Martín-Hernández, J; Marín, P J; Menéndez, H; Ferrero, C; Loenneke, J P; Herrero, A J

    2013-03-01

    This study aimed to gain an insight into the adaptations of muscle strength and skeletal muscle thickness after two different volumes of blood flow restriction training (BFRT), and compare them with high-intensity training. The sample was divided into four groups: low-volume, low-intensity BFRT (BFRT LV); high-volume, low-intensity BFRT (BFRT HV); traditional high-intensity resistance training (HIT); and a control group, which maintained their routine activities (CON). Leg extension one repetition maximum (1RM), isokinetic peak knee extension, and flexion torques at 60°/s and 180°/s as well as muscle thickness of the rectus femoris (RF) and vastus lateralis (VL) were assessed at baseline and after 5 weeks of training BFRT LV (7.03%, P muscular size or strength. Although similar increases in muscle thickness were observed between training groups, HIT increased 1RM performance to a greater extent compared to either volume of BFRT.

  8. Integration of acoustic radiation force and optical imaging for blood plasma clot stiffness measurement.

    Science.gov (United States)

    Wang, Caroline W; Perez, Matthew J; Helmke, Brian P; Viola, Francesco; Lawrence, Michael B

    2015-01-01

    Despite the life-preserving function blood clotting serves in the body, inadequate or excessive blood clot stiffness has been associated with life-threatening diseases such as stroke, hemorrhage, and heart attack. The relationship between blood clot stiffness and vascular diseases underscores the importance of quantifying the magnitude and kinetics of blood's transformation from a fluid to a viscoelastic solid. To measure blood plasma clot stiffness, we have developed a method that uses ultrasound acoustic radiation force (ARF) to induce micron-scaled displacements (1-500 μm) on microbeads suspended in blood plasma. The displacements were detected by optical microscopy and took place within a micro-liter sized clot region formed within a larger volume (2 mL sample) to minimize container surface effects. Modulation of the ultrasound generated acoustic radiation force allowed stiffness measurements to be made in blood plasma from before its gel point to the stage where it was a fully developed viscoelastic solid. A 0.5 wt % agarose hydrogel was 9.8-fold stiffer than the plasma (platelet-rich) clot at 1 h post-kaolin stimulus. The acoustic radiation force microbead method was sensitive to the presence of platelets and strength of coagulation stimulus. Platelet depletion reduced clot stiffness 6.9 fold relative to platelet rich plasma. The sensitivity of acoustic radiation force based stiffness assessment may allow for studying platelet regulation of both incipient and mature clot mechanical properties.

  9. 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....

  10. Variations in gastric compliance induced by acute blood volume changes in anesthetized rats

    Directory of Open Access Journals (Sweden)

    Graça J.R.V.

    2002-01-01

    Full Text Available The impact of acute volume imbalances on gastric volume (GV was studied in anesthetized rats (250-300 g. After cervical and femoral vessel cannulation, a balloon catheter was positioned in the proximal stomach. The opposite end of the catheter was connected to a barostat with an electronic sensor coupled to a plethysmometer. A standard ionic solution was used to fill the balloon (about 3.0 ml and the communicating vessel system, and to raise the reservoir liquid level 4 cm above the animals' xiphoid appendix. Due to constant barostat pressure, GV values were considered to represent the gastric compliance index. All animals were monitored for 90 min. After a basal interval, they were randomly assigned to normovolemic, hypervolemic, hypovolemic or restored protocols. Data were compared by ANOVA followed by Bonferroni's test. Mean arterial pressure (MAP, central venous pressure (CVP and GV values did not change in normovolemic animals (N = 5. Hypervolemic animals (N = 12 were transfused at 0.5 ml/min with a suspension of red blood cells in Ringer-lactate solution with albumin (12.5 ml/kg, which reduced GV values by 11.3% (P0.05. MAP and CVP values increased (P<0.05 after hypervolemia but decreased (P<0.05 with hypovolemia. In conclusion, blood volume level modulates gastric compliance, turning the stomach into an adjustable reservoir, which could be part of the homeostatic process to balance blood volume.

  11. Reliability of brain volume measurements: a test-retest dataset.

    Science.gov (United States)

    Maclaren, Julian; Han, Zhaoying; Vos, Sjoerd B; Fischbein, Nancy; Bammer, Roland

    2014-01-01

    Evaluation of neurodegenerative disease progression may be assisted by quantification of the volume of structures in the human brain using magnetic resonance imaging (MRI). Automated segmentation software has improved the feasibility of this approach, but often the reliability of measurements is uncertain. We have established a unique dataset to assess the repeatability of brain segmentation and analysis methods. We acquired 120 T1-weighted volumes from 3 subjects (40 volumes/subject) in 20 sessions spanning 31 days, using the protocol recommended by the Alzheimer's Disease Neuroimaging Initiative (ADNI). Each subject was scanned twice within each session, with repositioning between the two scans, allowing determination of test-retest reliability both within a single session (intra-session) and from day to day (inter-session). To demonstrate the application of the dataset, all 3D volumes were processed using FreeSurfer v5.1. The coefficient of variation of volumetric measurements was between 1.6% (caudate) and 6.1% (thalamus). Inter-session variability exceeded intra-session variability for lateral ventricle volume (P<0.0001), indicating that ventricle volume in the subjects varied between days.

  12. The orbital volume measurement in patients with ventriculoperitoneal shunt.

    Science.gov (United States)

    Kim, Jong-Min; Chang, Moo-Hwan; Kyung, Sungeun E

    2015-01-01

    Enophthalmos occurs from the increased bony volume or decreased soft tissue volume in the orbit and can be caused in patients with long-term ventriculoperitoneal (VP) shunt. This study tried to find out the change of orbital volume by measuring the orbital volume before and after operation in adult patients who underwent VP shunt for hydrocephalus. The 2 evaluators measured orbital volume by using ITK-SNAP 2.4 program with double-blind test for computed tomography images before and after operation targeting 36 patients over the age of 18 who underwent VP shunt with pressure-controlled valve from 2003 to 2011. Wilcoxon matched-pairs signed-rank test of GraphPad software was used to statistically analyze the difference in orbital volume change before and after operation. In case of mean pre-op orbital volume of total 36 patients, the right was measured as 23.72 ± 4.65 cm(3), the left as 23.47 ± 4.61 cm(3), the post-op right as 24.67 ± 4.70 cm(3), and the left as 24.18 ± 4.63 cm(3), showing no statistically significant difference (P = 0.106). The mean pre-op orbital volume of 14 people (28 eyes) followed for more than 11 months was 25.06 ± 4.58 cm(3) in the right and 24.4 ± 5.02 cm(3) in the left and the mean post-op orbital volume was 27.0 ± 4.28 cm(3) in the right and 25.76 ± 3.92 cm(3) in the left, showing statistically significant differences in the change of the volume before and after shunt operation (P = 0.0057). In patients who maintain long-term shunt devices after VP shunt, remodeling of matured orbital bone may be caused due to the change in pressure gradient between cranial cavity and orbit and the possible occurrence of resulting secondary enophthalmos by increased orbital volume should be considered.

  13. 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 a...... support. This could include context-aware patient adherence aids and clinical decision support systems for automatically validating self-measured data based on e-health and telemedicine technology....... 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...

  14. 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.

  15. Comparative technique in measurements of Ge detectors effective volumes

    Science.gov (United States)

    Demidova, E. V.; Kirpichnikov, I. V.; Vasenko, A. A.

    1999-01-01

    A simple and quick procedure was proposed for measurements of large coaxial Ge detectors effective volumes. It included a comparison of background spectra collected with several detectors without any shielding in an underground laboratory. Such measurements were performed in Homestake (USA) and Canfranc (Spain) laboratories with several 1 kg and 2 kg detectors. Monte-Carlo calculations confirmed that ratios of numbers of events in continua of the spectra should be either equal or very close to the ratios of the detectors effective volumes.

  16. 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.

  17. Dynamic noise correction for IVUS quantitative volume blood flow: methods and numerical validation.

    NARCIS (Netherlands)

    Lupotti, F.A.; Korte, C.L. de; Mastik, F.; Steen, A.F.W. van der

    2002-01-01

    In recent years, a new method to measure transverse blood flow based on the decorrelation of the radio-frequency (RF) signals, has been developed. Transverse blood flow estimation may be influenced by noise. In this paper, we investigated a new correlation-based method for noise correction. The deco

  18. Finite volume numerical solution to a blood flow problem in human artery

    Science.gov (United States)

    Wijayanti Budiawan, Inge; Mungkasi, Sudi

    2017-01-01

    In this paper, we solve a one dimensional blood flow model in human artery. This model is of a non-linear hyperbolic partial differential equation system which can generate either continuous or discontinuous solution. We use the Lax–Friedrichs finite volume method to solve this model. Particularly, we investigate how a pulse propagates in human artery. For this simulation, we give a single sine wave with a small time period as an impluse input on the left boundary. The finite volume method is successful in simulating how the pulse propagates in the artery. It detects the positions of the pulse for the whole time period.

  19. Magnetic Resonance Venous Volume Measurements in Peripheral Artery Disease (from ELIMIT).

    Science.gov (United States)

    Kamran, Hassan; Nambi, Vijay; Negi, Smita; Yang, Eric Y; Chen, Changyi; Virani, Salim S; Kougias, Panos; Lumsden, Alan B; Morrisett, Joel D; Ballantyne, Christie M; Brunner, Gerd

    2016-11-01

    The relation between the arterial and venous systems in patients with impaired lower extremity blood flow remains poorly described. The objective of this secondary analysis of the Effectiveness of Intensive Lipid Modification Medication in Preventing the Progression on Peripheral Artery Disease Trial was to determine the association between femoral vein (FV) volumes and measurements of peripheral artery disease. FV wall, lumen, and total volumes were quantified with fast spin-echo proton density-weighted magnetic resonance imaging scans in 79 patients with peripheral artery disease over 2 years. Reproducibility was excellent for FV total vessel (intraclass correlation coefficient 0.924, confidence interval 0.910 to 0.935) and lumen volumes (intraclass correlation coefficient 0.893, confidence interval 0.873 to 0.910). Baseline superficial femoral artery volumes were directly associated with FV wall (r = 0.46, p <0.0001), lumen (r = 0.42, p = 0.0001), and total volumes (r = 0.46, p <0.0001). The 2-year change in maximum walking time was inversely associated with the 24-month change in FV total volume (r = -0.45, p = 0.03). In conclusion, FV volumes can be measured reliably with fast spin-echo proton density-weighted magnetic resonance imaging, and baseline superficial femoral artery plaque burden is positively associated with FV volumes, whereas the 2-year change in FV volumes and leg function show an inverse relation.

  20. Assessment of relationship between physical activity volume and blood lipids concentration in Hamedanian middle age men

    Directory of Open Access Journals (Sweden)

    Majid Jalili

    2012-06-01

    Full Text Available Background: Inactivity is a leading contributor to chronic health problems. Physical activity (PA is an important element in maintaining the health and functional ability in the population and has favorable effects on lipid profile in adults. Here, we examined the effects of pedometer-based PA (step/day in healthy middle age men. Methods: Height, weight, body mass index (BMI, and daily oxygen consumption (VO2peak were measured in 27 active and sedentary healthy middle aged men (40-65 yr. Subjects wore a pedometer throughout the day for three consecutive weeks, and average steps per day (physical activity volume were measured. Fasting serum concentrations of total cholesterol (TC, triglyceride (TG, high density lipoprotein-cholesterol (HDL-C, and low density lipoprotein-cholesterol (LDL-C were measured. Results: Mean of Daily steps in the Active group (AG (12632±3957 steps/day was significantly higher than sedentary group (SG (5347±1631step/day (p0.05. A significant correlation was found between average steps per day and TG (-0.424, P = 0.027 TC (-0.389, P = 0.045 TC/HDL-C (-0.469 P = 0.014 HDL-C/LDL-C (-0.390 P = 0.044 and Daily Oxygen Consumption (-0.853 P = 0.000. Conclusion: It seems that, healthy middle-aged men, who have more ambulatory activity (average of 12,500 step/day, have significantly better blood lipids’ profile.

  1. 30 CFR 250.1163 - How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and...

    Science.gov (United States)

    2010-07-01

    ... volumes and liquid hydrocarbon burning volumes, and what records must I maintain? 250.1163 Section 250..., and Burning Hydrocarbons § 250.1163 How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and what records must I maintain? (a) If your facility processes more than...

  2. Representative volume element of asphalt pavement for electromagnetic measurements

    Directory of Open Access Journals (Sweden)

    Terhi Pellinen

    2015-02-01

    Full Text Available The motivation for this study was to investigate the representative volume element (RVE needed to correlate the nondestructive electromagnetic (EM measurements with the conventional destructive asphalt pavement quality control measurements. A large pavement rehabilitation contract was used as the test site for the experiment. Pavement cores were drilled from the same locations where the stationary and continuous Ground Penetrating Radar (GPR measurements were obtained. Laboratory measurements included testing the bulk density of cores using two methods, the surface-saturated dry method and determining bulk density by dimensions. Also, Vector Network Analyzer (VNA and the through specimen transmission configuration were employed at microwave frequencies to measure the reference dielectric constant of cores using two different footprint areas and therefore volume elements. The RVE for EM measurements turns out to be frequency dependent; therefore in addition to being dependent on asphalt mixture type and method of obtaining bulk density, it is dependent on the resolution of the EM method used. Then, although the average bulk property results agreed with theoretical formulations of higher core air void content giving a lower dielectric constant, for the individual cores there was no correlation for the VNA measurements because the volume element seizes deviated. Similarly, GPR technique was unable to capture the spatial variation of pavement air voids measured from the 150-mm drill cores. More research is needed to determine the usable RVE for asphalt.

  3. Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

    Energy Technology Data Exchange (ETDEWEB)

    McCommis, Kyle S.; Goldstein, Thomas A.; Pilgram, Thomas [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Abendschein, Dana R. [Washington University School of Medicine, Center for Cardiovascular Research, St. Louis, MO (United States); Misselwitz, Bernd [Bayer Schering Pharma AG, Berlin (Germany); Gropler, Robert J. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, Center for Cardiovascular Research, St. Louis, MO (United States); Zheng, Jie [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Cardiovascular Imaging Lab, St. Louis, MO (United States)

    2010-08-15

    To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and {sup 99m}Tc-labeled red blood cells were injected to obtain respective gold standards. Microsphere-measured MBF and {sup 99m}Tc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. (orig.)

  4. Measuring cell surface area and deformability of individual human red blood cells over blood storage using quantitative phase imaging

    Science.gov (United States)

    Park, Hyunjoo; Lee, Sangyun; Ji, Misuk; Kim, Kyoohyun; Son, Yonghak; Jang, Seongsoo; Park, Yongkeun

    2016-10-01

    The functionality and viability of stored human red blood cells (RBCs) is an important clinical issue in transfusions. To systematically investigate changes in stored whole blood, the hematological properties of individual RBCs were quantified in blood samples stored for various periods with and without a preservation solution called citrate phosphate dextrose adenine-1 (CPDA-1). With 3-D quantitative phase imaging techniques, the optical measurements for 3-D refractive index (RI) distributions and membrane fluctuations were done at the individual cell level. From the optical measurements, the morphological (volume, surface area and sphericity), biochemical (hemoglobin content and concentration), and mechanical parameters (dynamic membrane fluctuation) were simultaneously quantified to investigate the functionalities and progressive alterations of stored RBCs. Our results show that stored RBCs without CPDA-1 had a dramatic morphological transformation from discocytes to spherocytes within two weeks which was accompanied by significant decreases in cell deformability and cell surface area, and increases in sphericity. However, the stored RBCs with CPDA-1 maintained their morphology and deformability for up to 6 weeks.

  5. Bioimpedance Measurement of Segmental Fluid Volumes and Hemodynamics

    Science.gov (United States)

    Montgomery, Leslie D.; Wu, Yi-Chang; Ku, Yu-Tsuan E.; Gerth, Wayne A.; DeVincenzi, D. (Technical Monitor)

    2000-01-01

    Bioimpedance has become a useful tool to measure changes in body fluid compartment volumes. An Electrical Impedance Spectroscopic (EIS) system is described that extends the capabilities of conventional fixed frequency impedance plethysmographic (IPG) methods to allow examination of the redistribution of fluids between the intracellular and extracellular compartments of body segments. The combination of EIS and IPG techniques was evaluated in the human calf, thigh, and torso segments of eight healthy men during 90 minutes of six degree head-down tilt (HDT). After 90 minutes HDT the calf and thigh segments significantly (P < 0.05) lost conductive volume (eight and four percent, respectively) while the torso significantly (P < 0.05) gained volume (approximately three percent). Hemodynamic responses calculated from pulsatile IPG data also showed a segmental pattern consistent with vascular fluid loss from the lower extremities and vascular engorgement in the torso. Lumped-parameter equivalent circuit analyses of EIS data for the calf and thigh indicated that the overall volume decreases in these segments arose from reduced extracellular volume that was not completely balanced by increased intracellular volume. The combined use of IPG and EIS techniques enables noninvasive tracking of multi-segment volumetric and hemodynamic responses to environmental and physiological stresses.

  6. Use of dried blood for measurement of trans fatty acids

    Directory of Open Access Journals (Sweden)

    Ramakrishnan Lakshmy

    2009-07-01

    Full Text Available Abstract Background Fatty acid measurements especially trans fatty acid has gained interest in recent times. Among the various available biomarkers, adipose tissue is considered to be the best for the long term dietary intake but the invasive nature of tissue aspiration reduces its utility. Phlebotomy is a much less invasive method of sample collection when a large number of participants are involved in the study and therefore is an alternative, most suitable for large population based studies. In the present study fatty acid (with special emphasis on trans fatty acid extraction from blood spotted and dried on filter paper was carried out to simplify the sample collection procedure and transportation. Methods Blood samples were collected from 19 healthy volunteers. The blood was spotted (30 spots of 10 μl each on filter paper, dried at room temperature and stored at 4°C in zip-lock poly bags. For comparison whole blood stored at -70°C was simultaneously analyzed. Results A good agreement was seen between trans fatty acid values obtained in dried blood and whole blood as evident from the pearson correlation coefficients ('r' for monounsaturated (trans 0.70 and for polyunsaturated (trans 0.692 respectively. The intraclass correlation coefficient for monounsaturated trans was 0.805 and for polyunsarurated trans was 0.776. Conclusion Dried blood spots can be used for trans fatty acid analysis.

  7. Detection of Low-volume Blood Loss: Compensatory Reserve Versus Traditional Vital Signs

    Science.gov (United States)

    2014-01-01

    Detection of low-volume blood loss: Compensatory reserve versus traditional vital signs Camille L. Stewart, MD, Jane Mulligan , PhD, Greg Z. Grudic... Mulligan J., Grudic G. Z., Convertino V. A., Moulton S. L., 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S...Jane Mulligan (own ership), Greg Z. Grudic (ownership), and Steven L. Moulton (owner ship). This work is supported by the US Army Medical Research and

  8. Reliability and Accuracy of Brain Volume Measurement on MR Imaging

    DEFF Research Database (Denmark)

    Yamagchii, Kechiro; Lassen, Anders; Ring, Poul

    1998-01-01

    Yamaguchi, K., Lassen, A. And Ring, P. Reliability and Accuracy of Brain Volume Measurement on MR Imaging. Abstract at ESMRMB98 European Society for Magnetic Resonance in Medicine and Biology, Geneva, Sept 17-20, 1998 Danish Research Center for Magnetic Resonance, Hvidovre University Hospital...

  9. Real-time contrast-enhanced ultrasound determination of microvascular blood volume in abdominal subcutaneous adipose tissue in man. Evidence for adipose tissue capillary recruitment

    DEFF Research Database (Denmark)

    Tobin, L; Simonsen, L; Bülow, J

    2010-01-01

    The adipose tissue metabolism is dependent on its blood perfusion. During lipid mobilization e.g. during exercise and during lipid deposition e.g. postprandial, adipose tissue blood flow is increased. This increase in blood flow may involve capillary recruitment in the tissue. We investigated...... the basic and postprandial microvascular volume in adipose tissue using real-time contrast-enhanced ultrasound (CEU) imaging in healthy normal weight subjects. In nine subjects, CEU was performed in abdominal subcutaneous adipose tissue and in the underlying skeletal muscle after a bolus injection...... of ultrasound contrast agent to establish the reproducibility of the technique. In nine subjects, the effect of an oral glucose load on blood flow and microvascular volume was measured in abdominal subcutaneous adipose tissue and forearm skeletal muscle. ¹³³Xe washout and venous occlusion strain...

  10. [The landmarks of the measurement of cerebral blood flow].

    Science.gov (United States)

    István, Nyáry

    2008-01-30

    History of the measurement of local cerebral blood flow may cover a period of one and a half centuries. Parallel forthcoming of both theoretical and technical development were the key elements of ensuing progress resulting in the present state, when by the aid of in vivo blood flow and metabolic maps, we can visualize locales of brain functioning and their interconnections. Two theoretical landmarks should be mentioned in this historic process. First, the work of Adolf Fick, as the starter of quantitative measurements in this field, and Seymour Kety's model of a single, homogenously perfused tissue element. The solution of this model, in the form of Kety's equation is still fundamental to present day blood flow mapping techniques. Among the numerous investigators over the past years, two Hungarian scientist can be named as major contributors. Kálmán Sántha made substantial studies with continuous registration of local cerebral blood flow by the aid of thermocouples, while Emil P6sztor invented the hydrogen clearance method for the measurement of local cerebral blood flow both in human and in animal studies.

  11. Study of the spatial distribution of the absorbed dose in blood volumes irradiated using a teletherapy unit

    Energy Technology Data Exchange (ETDEWEB)

    Goes, E.G., E-mail: eggoes@terra.com.b [Regional Blood Center of Ribeirao Preto, Ribeirao Preto, SP (Brazil); Nicolucci, P.; Nali, I.C. [Physics and Mathematics Department, University of Sao Paulo, Ribeirao Preto, SP (Brazil); Pela, C.A.; Bruco, J.L. [Physics and Mathematics Department, University of Sao Paulo, Ribeirao Preto, SP (Brazil); Center of Instrumentation, Dosimetry and Radioprotection, University of Sao Paulo, Ribeirao Preto, SP (Brazil); Borges, J.C. [Center of Instrumentation, Dosimetry and Radioprotection, University of Sao Paulo, Ribeirao Preto, SP (Brazil); Covas, D.T. [Regional Blood Center of Ribeirao Preto, Ribeirao Preto, SP (Brazil); Center for Cell-Based Therapy, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP (Brazil)

    2010-06-15

    Blood irradiation can be performed using a dedicated blood irradiator or a teletherapy unit. A thermal device providing appropriate storage conditions during blood components irradiation with a teletherapy unit has been recently proposed. However, the most appropriated volume of the thermal device was not indicated. The goal of this study was to indicate the most appropriated blood volume for irradiation using a teletherapy unit in order to minimize both the dose heterogeneity in the volume and the blood irradiation time using these equipments. Theoretical and experimental methods were used to study the dose distribution in the blood volume irradiated using a linear accelerator and a cobalt-60 therapy machine. The calculation of absorbed doses in the middle plane of cylindrical acrylic volumes was accomplished by a treatment planning system. Experimentally, we also used cylindrical acrylic phantoms and thermoluminescent dosimeters to confirm the calculated doses. The data obtained were represented by isodose curves. We observed that an irradiation volume should have a height of 28 cm and a diameter of 28 cm and a height of 35 cm and a diameter of 35 cm, when the irradiation is to be performed by a linear accelerator and a cobalt-60 teletherapy unit, respectively. Calculated values of relative doses varied from 93% to 100% in the smaller volume, and from 66% to 100% in the largest one. A difference of 5.0%, approximately, was observed between calculated and experimental data. The size of these volumes permits the irradiation of blood bags in only one bath without compromising the homogeneity of the absorbed dose over the irradiated volume. Thus, these irradiation volumes can be recommend to minimize the irradiation time when a teletherapy unit is used to irradiate blood.

  12. Study of the spatial distribution of the absorbed dose in blood volumes irradiated using a teletherapy unit

    Science.gov (United States)

    Góes, E. G.; Nicolucci, P.; Nali, I. C.; Pelá, C. A.; Bruço, J. L.; Borges, J. C.; Covas, D. T.

    2010-06-01

    Blood irradiation can be performed using a dedicated blood irradiator or a teletherapy unit. A thermal device providing appropriate storage conditions during blood components irradiation with a teletherapy unit has been recently proposed. However, the most appropriated volume of the thermal device was not indicated. The goal of this study was to indicate the most appropriated blood volume for irradiation using a teletherapy unit in order to minimize both the dose heterogeneity in the volume and the blood irradiation time using these equipments. Theoretical and experimental methods were used to study the dose distribution in the blood volume irradiated using a linear accelerator and a cobalt-60 therapy machine. The calculation of absorbed doses in the middle plane of cylindrical acrylic volumes was accomplished by a treatment planning system. Experimentally, we also used cylindrical acrylic phantoms and thermoluminescent dosimeters to confirm the calculated doses. The data obtained were represented by isodose curves. We observed that an irradiation volume should have a height of 28 cm and a diameter of 28 cm and a height of 35 cm and a diameter of 35 cm, when the irradiation is to be performed by a linear accelerator and a cobalt-60 teletherapy unit, respectively. Calculated values of relative doses varied from 93% to 100% in the smaller volume, and from 66% to 100% in the largest one. A difference of 5.0%, approximately, was observed between calculated and experimental data. The size of these volumes permits the irradiation of blood bags in only one bath without compromising the homogeneity of the absorbed dose over the irradiated volume. Thus, these irradiation volumes can be recommend to minimize the irradiation time when a teletherapy unit is used to irradiate blood.

  13. Impact of the Implementation of ESA 2010 on Volume Measurement

    Directory of Open Access Journals (Sweden)

    Petr Musil

    2016-06-01

    Full Text Available Volume indices are connected with statistical deflation that means recalculation of macro-aggregates to constant prices. Price calculations have to follow changes in definition or delineation of macro-aggregates. New standards of National Accounts (SNA 2008, ESA 2010 respectively bring many changes that should be taken into account in volume measures. The aim of this paper is to present new methods of deflation that respekt updated definitions and principles. Concept of foreign trade has been changed significantly as globalization is going faster and faster. Re-export and merchanting have become more important especially in small open economies such as the Czech Republic. This phenomenon should be reflected in constant prices calculations. Changes in methodology have also affected volume indices.

  14. Laser-diffraction slit rheometer to measure red blood cell deformability

    Science.gov (United States)

    Shin, S.; Ku, Y. H.; Park, M. S.; Moon, S. Y.; Jang, J. H.; Suh, J. S.

    2004-02-01

    The laser-diffraction technique has been applied to design a slit rheometer for measuring red blood cell deformability over a range of shear stress. Flow-rate and pressure-drop measurements are replaced with a measurement of pressure variation with time. Using a precision pressure transducer, one can measure the variation of pressure in the vacuum chamber, p(t), from which the shear stress and shear rate are mathematically calculated. In addition, a laser beam traverses a diluted blood suspension and is diffracted by red blood cells (RBCs) in the volume. The diffraction patterns are captured by a charge coupled device-video camera, linked to a frame grabber integrated with a computer. When deforming under decreasing shear stress, RBCs change gradually from the prolate ellipsoid towards a circular biconcave morphology. The elongation index as a measure of RBC deformability is determined from an isointensity curve in the diffraction pattern using an ellipse-fitting program. The advantages of this design are simplicity, i.e., ease of operation and no moving parts, low cost, short operating time, and the disposable kit which is in contact with the blood sample.

  15. Measurement of the left ventricular regurgitation by gated cardiac blood pool scan: Before and after valvular replacement surgery

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sung Hae; Chung, June Key; Lee, Myung Chul; Cho, Bo Youn; Seo, Jung Don; Lee, Young Woo; Koh, Chang Soon; Suh, Kyung Phill; Lee, Yung Kyoon [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1982-09-15

    Quantification of the regurgitation amount is important before and after valvular replacement surgery. Until now cardiac catheterization with cine ventriculography, echocardiography have been used to measure the regurgitation amount, but also have many limitations EKG gated cardiac blood pool scan provides a simple, non-invasive method for quantify the regurgitation amount. By calculating the ratio of left ventricular to right ventricular stroke counts (stroke volume ratio) in gated blood pool scan, we measured the left ventricular regurgitation amount in 28 cases of valvular regurgitation and 25 cases of normal group. 1) Stroke volume ratio was higher in cases of valvular regurgitation(2.11+-0.58) than in cases of normal control(l.15+-0.31). (p<0.01). 2) Stroke volume ratio was classified by regurgitation grade using X-ray cine ventriculography. In grades of mild regurgitation(Grade I-II), stroke volume ratio was 2.02+-0.29, and in grades of severe regurgitation(Grade III-IV), stroke volume ratio was 2.55+-0.34, so stroke volume ratio was well correlated with the grade of X-ray cine ventriculography. 3) Stroke volume ratio was classified by functional class made in New York Heart Association. In classes of mild regurgitation (class I-II), stroke volume ratio was 2.08+-0.26, and in classes of severe regurgitation (class III-IV), stroke volume ratio was 2.55+-0.38, Stroke volume ratio well represented the functional class. 4) After aortic and mitral valve replacement in 28 patients, the stroke volume ratio decreased from 2.11+-0.58 to 1.06+-0.26. Gated blood pool scan provides a noninvasive method of quantifying valvular regurgitation and assessing the result of surgical interventions.

  16. Methods for measurement of cerebral blood flow in man

    DEFF Research Database (Denmark)

    Lassen, N A

    1976-01-01

    A survey of the currently available methods for the measurement of cerebral blood flow in man is given. Many of the clinically important brain diseases such as tumors, stroke, brain trauma or epilepsy entail focal or regional flow alterations. Therefore a special emphasis is placed on methods all...

  17. Pitfalls in blood pressure measurement in daily practice

    NARCIS (Netherlands)

    Houweling, ST; Kleefstra, N; Lutgers, HL; Groenier, KH; Meyboom-de Jong, B; Bilo, HJG

    2006-01-01

    Background. Accurate blood pressure (BP) readings and correctly interpreting the obtained values are of great importance. However, there is considerable variation in the different BP measuring methods suggested in guidelines and used in hypertension trials. Objective. To compare the different method

  18. Invasively Measured Aortic Systolic Blood Pressure and Office Systolic Blood Pressure in Cardiovascular Risk Assessment

    DEFF Research Database (Denmark)

    Laugesen, Esben; Knudsen, Søren T; Hansen, Klavs W;

    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...

  19. Development of a simple device for processing whole-blood samples into measured aliquots of plasma.

    Science.gov (United States)

    Burtis, C A; Johnson, W F; Walker, W A

    1986-09-01

    A capillary processor and aliquoter has been designed and fabricated that is capable of accepting aliquots of whole blood and automatically processing them into discrete aliquots of plasma. The device consists of two disks, each of which contains 16 individual capillaries and a processing rotor. One disk accepts larger capillaries that hold approximately 100 microL of whole blood each. The second disk accepts 2.54-cm-long precision capillaries of various internal diameters, which provide exact sample volumes from 1 to 10 microL. The processing rotor contains 16 individual compartments and chambers to accept both disks. Applying centrifugal force transfers the aliquots of whole blood into their respective compartments, where they are separated into cellular and plasma fractions. As the rotor speed is slowly decreased, an aliquot of plasma is withdrawn by capillary action into each measuring capillary. The disk containing the 16 measured aliquots of plasma is then removed and placed into a modified rotor for conventional centrifugal analysis. This device can entrain and deliver microliter volumes of liquids with precision and accuracy (1-2%) near that of mechanical pipettes. Assays of the separated plasma aliquots also have acceptable precision (e.g., CVs approximately 3% for measurements of serum enzymes).

  20. Evaluation of automated blood pressure measurements during exercise testing.

    Science.gov (United States)

    Hossack, K F; Gross, B W; Ritterman, J B; Kusumi, F; Bruce, R A

    1982-11-01

    Measurements of systolic (SBP) and diastolic (DBP) blood pressure were made at rest and during symptom-limited exercise with an automated blood pressure measuring device (EBPM). Comparisons were made between the EBPM readings and those made with mercury manometer. Correlations were high (SBP r = 0.92, DBP r = 0.80) when readings were made in the same arm, but were less satisfactory when the cuffs were on different arms (SBP r = 0.80, DBP r = 0.46). The correlation between two mercury manometer readings was SBP r = 0.90, and DBP r = 0.75. Comparison between EBPM and intra-arterial measurements were similar (SBP r = 0.74, DBP r = 0.79) to comparison between mercury manometer and intra-arterial measurements (SBP r = 0.81, DBP r = 0.61). The EBPM detected SBP at consistently higher levels than did physicians, which may be an advantage in the noisy environment of an exercise test. There was a definite tendency for physicians to record blood pressure to the nearest 10 mm Hg, whereas the frequency distribution curve for EBPM measurements was smoother. The EBPM operated satisfactorily at rest and during maximal exercise and gave as reliable measurements as a physician using a mercury manometer and, in the small number of available cases, detected exertional hypotension more often than the physician.

  1. Study of accurate volume measurement system for plutonium nitrate solution

    Energy Technology Data Exchange (ETDEWEB)

    Hosoma, T. [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works

    1998-12-01

    It is important for effective safeguarding of nuclear materials to establish a technique for accurate volume measurement of plutonium nitrate solution in accountancy tank. The volume of the solution can be estimated by two differential pressures between three dip-tubes, in which the air is purged by an compressor. One of the differential pressure corresponds to the density of the solution, and another corresponds to the surface level of the solution in the tank. The measurement of the differential pressure contains many uncertain errors, such as precision of pressure transducer, fluctuation of back-pressure, generation of bubbles at the front of the dip-tubes, non-uniformity of temperature and density of the solution, pressure drop in the dip-tube, and so on. The various excess pressures at the volume measurement are discussed and corrected by a reasonable method. High precision-differential pressure measurement system is developed with a quartz oscillation type transducer which converts a differential pressure to a digital signal. The developed system is used for inspection by the government and IAEA. (M. Suetake)

  2. Predicting stroke outcome using DCE-CT measured blood velocity

    Science.gov (United States)

    Oosterbroek, Jaap; Bennink, Edwin; Dankbaar, Jan Willem; Horsch, Alexander D.; Viergever, Max A.; Velthuis, Birgitta K.; de Jong, Hugo W. A. M.

    2015-03-01

    CT plays an important role in the diagnosis of acute stroke patients. Dynamic contrast enhanced CT (DCE-CT) can estimate local tissue perfusion and extent of ischemia. However, hemodynamic information of the large intracranial vessels may also be obtained from DCE-CT data and may contain valuable diagnostic information. We describe a novel method to estimate intravascular blood velocity (IBV) in large cerebral vessels using DCE-CT data, which may be useful to help predict stroke outcome. DCE-CT scans from 34 patients with isolated M1 occlusions were included from a large prospective multi-center cohort study of patients with acute ischemic stroke. Gaussians fitted to the intravascular data yielded the time-to-peak (TTP) and cerebral-blood-volume (CBV). IBV was computed by taking the inverse of the TTP gradient magnitude. Voxels with a CBV of at least 10% of the CBV found in the arterial input function were considered part of a vessel. Mid-sagittal planes were drawn manually and averages of the IBV over all vessel-voxels (arterial and venous) were computed for each hemisphere. Mean-hemisphere IBV differences, mean-hemisphere TTP differences, and hemisphere vessel volume differences were used to differentiate between patients with good and bad outcome (modified Rankin Scale score <3 versus ≥3 at 90 days) using ROC analysis. AUCs from the ROC for IBV, TTP, and vessel volume were 0.80, 0.67 and 0.62 respectively. In conclusion, IBV was found to be a better predictor of patient outcome than the parameters used to compute it and may be a promising new parameter for stroke outcome prediction.

  3. Early high-sodium solid diet does not affect sodium intake, sodium preference, blood volume and blood pressure in adult Wistar-Kyoto rats.

    Science.gov (United States)

    Ufnal, Marcin; Drapala, Adrian; Sikora, Mariusz; Zera, Tymoteusz

    2011-07-01

    A high-Na diet may lead to the development of hypertension in both humans and rats; however, the causes of Na intake in amounts greater than physiologically needed as well as the mechanisms whereby high-Na food elevates blood pressure are not clear. Therefore, we decided to test the hypothesis that a high-Na diet introduced after suckling affects Na intake, food preference, resting blood pressure and blood volume in adult rats. Male Wistar-Kyoto (WKY) rats, 4 weeks old, were divided into three groups and placed on either a high-Na (3.28%), a medium-Na (0.82%) or a regular diet (0.22%) with the same energy content for 8 weeks. Subsequently, food preference, resting arterial blood pressure, blood volume, plasma osmolality and Na blood level were evaluated. When offered a choice of diets, all the groups preferred the regular chow, and there was no significant difference in total Na intake between the groups. When the rats experienced the change from their initial chow to a new one with different Na content, they continued to eat the same amount of food. Body weight, resting arterial blood pressure, blood volume, plasma osmolality and Na blood level were comparable between the groups. In conclusion, the results show that a high-Na diet introduced immediately after suckling does not affect Na preference and Na intake in adult WKY rats. Furthermore, the findings provide evidence that both blood volume and arterial blood pressure are highly protected in normotensive rats on a high-Na diet.

  4. Measurement of Gallbladder Volume with Ultrasonography in Pregnant Women

    Directory of Open Access Journals (Sweden)

    Sait Kapicioglu

    2000-01-01

    Full Text Available Fasting and postprandial gallbladder volumes were investigated using ultrasonography in three groups (10 subjects in each of healthy women: third trimester pregnant women, postpartum women up to 10 days after giving birth and nonpregnant controls. The scans were performed at 09:00 after a 12 h fast. After the basal measurement was taken, gallbladder volumes were rescanned in 15 min intervals for 60 mins. At the end of this period, all volunteers received a standard liquid test meal, and scans were performed again for 1 h. The mean basal gallbladder volume was 22.2±4.2 mL in the nonpregnant (control group. In the third trimester group, the basal volume was 37.8±10.5 mL – 70.5% higher than in the nonpregnant group (P<0.001. In the postpartum group, the mean basal volume was 37.9% lower (27.4±6.5 mL than that of the third trimester group (P<0.02. This basal volume was 23.6% greater than that of the control group (P<0.05. After administration of a test meal, the postprandial gallbladder volumes decreased during the first few minutes compared with baseline values. The volumes decreased by 10.2% to 39.8% (23.5±7.3 to 34.0±10.2; P<0.01 in the third trimester group, by 14.9% to 43.2% (16.6±4.3 to 23.3±5.5; P<0.01, 0.001 in the postpartum group and by 19.2% to 51.6% (11.9±3.5 to 17.9±3.6; P<0.02, 0.05, 0.01, 0.001 in the control group. Postprandial mean gallbladder volumes of the third trimester (P<0.02 and postpartum groups (P<0.02 to 0.01 were significantly different from those of the control group. In conclusion, incomplete emptying of the gallbladder after eating during the third trimester of pregnancy may contribute to cholesterol-gallstone formation, and pregnancy may thus increase the risk of gallstones.

  5. Difference in intraosseous blood vessel volume and number in osteoporotic model mice induced by spinal cord injury and sciatic nerve resection.

    Science.gov (United States)

    Ding, Wen-Ge; Yan, Wei-hong; Wei, Zhao-Xiang; Liu, Jin-Bo

    2012-07-01

    In the present study, we examined intraosseous blood vessel parameters of the tibial metaphysis in mice using microcomputed tomography (µCT) to investigate the relationship between post-nerve-injury osteoporosis and local intraosseous blood vessel volume and number. Mice were randomly divided into groups receiving spinal cord injury (SCI), sciatic nerve resection group (NX), or intact controls (30 mice/group). Four weeks after surgery, mice were perfused with silicone and the distribution of intraosseous blood vessels analyzed by μCT. The bone density, μCT microstructure, biomechanical properties, and the immunohistochemical and biochemical indicators of angiogenesis were also measured. The SCI group showed significantly reduced tibial metaphysis bone density, μCT bone microstructure, tibial biomechanical properties, indicators of angiogenesis, and intraosseous blood vessel parameters compared to the NX group. Furthermore, the spinal cord-injured mice exhibited significantly decreased intraosseous blood vessel volume and number during the development of osteoporosis. In conclusion, these data suggest that decreased intraosseous blood vessel volume and number may play an important role in the development of post-nerve-injury osteoporosis.

  6. Effects of respiratory muscle unloading on leg muscle oxygenation and blood volume during high-intensity exercise in chronic heart failure.

    Science.gov (United States)

    Borghi-Silva, Audrey; Carrascosa, Cláudia; Oliveira, Cristino Carneiro; Barroco, Adriano C; Berton, Danilo C; Vilaça, Debora; Lira-Filho, Edgar B; Ribeiro, Dirceu; Nery, Luiz Eduardo; Neder, J Alberto

    2008-06-01

    Blood flow requirements of the respiratory muscles (RM) increase markedly during exercise in chronic heart failure (CHF). We reasoned that if the RM could subtract a fraction of the limited cardiac output (QT) from the peripheral muscles, RM unloading would improve locomotor muscle perfusion. Nine patients with CHF (left ventricle ejection fraction = 26 +/- 7%) undertook constant-work rate tests (70-80% peak) receiving proportional assisted ventilation (PAV) or sham ventilation. Relative changes (Delta%) in deoxy-hemoglobyn, oxi-Hb ([O2Hb]), tissue oxygenation index, and total Hb ([HbTOT], an index of local blood volume) in the vastus lateralis were measured by near infrared spectroscopy. In addition, QT was monitored by impedance cardiography and arterial O2 saturation by pulse oximetry (SpO2). There were significant improvements in exercise tolerance (Tlim) with PAV. Blood lactate, leg effort/Tlim and dyspnea/Tlim were lower with PAV compared with sham ventilation (P 0.05). Unloaded breathing, however, was related to enhanced leg muscle oxygenation and local blood volume compared with sham, i.e., higher Delta[O2Hb]% and Delta[HbTOT]%, respectively (P < 0.05). We conclude that RM unloading had beneficial effects on the oxygenation status and blood volume of the exercising muscles at similar systemic O2 delivery in patients with advanced CHF. These data suggest that blood flow was redistributed from respiratory to locomotor muscles during unloaded breathing.

  7. [Measurement of cerebral blood flow using phase-contrast MRI].

    Science.gov (United States)

    Obata, T; Shishido, F; Koga, M; Ikehira, H; Kimura, F; Yoshida, K

    1997-07-01

    The development of phase-contrast magnetic resonance imaging(P-C MRI) provides a noninvasive method for measurement of volumetric blood flow(VFR). The VFR of the left and right internal carotid arteries and basilar artery were measured using P-C MRI, and total cerebral blood flow(tCBF) was calculated by summing up the VFR values in three vessels. We investigated the changes in these blood flows as influenced from age, head size, height, weight, body surface area and handedness. Moreover, regional CBF(rCBF) was measured by combining with the single photon emission computed tomography(SPECT) of 123I. The blood flows were 142 +/- 58 mL/ min(mean +/- SD) in the basilar artery, 229 +/- 86 mL/min in the left, 223 +/- 58 mL/min in the right internal carotid artery, and tCBF was 617 +/- 128 mL/min(Ref. Magn Resn Imaging 14:P. 1143, 1996). Significant increases were observed in head-size-related change of VFR in the basilar artery and height-related change of tCBF. The value of rCBF was easily acquired in combination with SPECT. Phase-contrast MRI is useful for a noninvasive and rapid analysis of cerebral VFR and has potential for clinical use.

  8. Intraobserver and interobserver agreement of volume perfusion CT (VPCT) measurements in patients with lung lesions

    Energy Technology Data Exchange (ETDEWEB)

    Sauter, Alexander W., E-mail: alexander.sauter@klinikum.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Merkle, Anne, E-mail: anne_merkle@web.de [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Schulze, Maximilian, E-mail: maximilian.schulze@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Spira, Daniel, E-mail: daniel.spira@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Hetzel, Juergen, E-mail: juergen.hetzel@med.uni-tuebingen.de [Departments of Oncology, Hematology, Immunology, Rheumatology and Pulmonology, University Hospital of Tuebingen, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany); Claussen, Claus D., E-mail: claus.claussen@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Horger, Marius S., E-mail: marius.horger@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)

    2012-10-15

    Objectives: To evaluate intraobserver and interobserver agreement of manually encompassed lung lesions for perfusion measurements using volume-perfusion computed tomography (VPCT). Materials and methods: Institutional review board approval and informed consent were obtained. HIPAA guidelines were followed. A 65-s dynamic study was acquired with scan parameters 80 kV, 60 mA s (80 mA s for patients ≥70 kg), 128 × 0.6 mm collimation. Blood flow (BF), blood volume (BV) and K{sup trans} parameters were determined by syngo volume perfusion CT body with 88 lesions analyzed retrospectively. Results: Within-subject coefficients of variation for intraobserver agreement (range 6.59–12.82%) were superior to those for interobserver agreement (range 21.75–38.30%). Size-dependent analysis revealed lower agreements for lesions <4 cm as compared to larger lesions. Additionally, agreements of the upper, middle and lower lung zones were different. Conclusions: Intraobserver agreement was substantial for VPCT lung cancer perfusion measurements encouraging the use for tumor characterization and therapy response monitoring. Interobserver agreement is limited and unexperienced readers should be trained before using this new method.

  9. Improved Perfusion MR Imaging Assessment of Intracerebral Tumor Blood Volume and Antiangiogenic Therapy Efficacy in a Rat Model with Ferumoxytol

    OpenAIRE

    Gahramanov, Seymur; Muldoon, Leslie L; Li, Xin; Neuwelt, Edward A.

    2011-01-01

    Our findings suggest that, at perfusion MR imaging, more consistent estimations of relative cerebral blood volume are provided with ferumoxytol than with gadolinium-based contrast agents regardless of the permeability of the tumor vasculature.

  10. Estimated central blood volume in cirrhosis: relationship to sympathetic nervous activity, beta-adrenergic blockade and atrial natriuretic factor

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Bendtsen, F; Gerbes, A L

    1992-01-01

    The estimated central blood volume (i.e., blood volume in the heart cavities, lungs and central arterial tree) was determined by multiplying cardiac output by circulatory mean transit time in 19 patients with cirrhosis and compared with sympathetic nervous activity and circulating level of atrial...... natriuretic factor. Arterial norepinephrine level, an index of overall sympathetic nervous activity (3.08 nmol/L in patients vs. 1.36 nmol/L in controls; p blood volume (mean = 23 ml/kg in patients vs. 27 ml/kg in controls; p ....05). Similarly, renal venous norepinephrine level (an index of renal sympathetic tone; 4.26 nmol/L in patients vs. 1.78 nmol/L in controls; p blood volume (r = -0.53, n = 18, p

  11. Ultrasound modulated light blood flow measurement using intensity autocorrelation function: a Monte-Carlo simulation

    Science.gov (United States)

    Tsalach, A.; Metzger, Y.; Breskin, I.; Zeitak, R.; Shechter, R.

    2014-03-01

    Development of techniques for continuous measurement of regional blood flow, and in particular cerebral blood flow (CBF), is essential for monitoring critical care patients. Recently, a novel technique, based on ultrasound modulation of light was developed for non-invasive, continuous CBF monitoring (termed ultrasound-tagged light (UTL or UT-NIRS)), and shown to correlate with readings of 133 Xe SPECT1 and laser Doppler2. Coherent light is introduced into the tissue concurrently with an Ultrasound (US) field. Displacement of scattering centers within the sampled volume induced by Brownian motion, blood flow and the US field affects the photons' temporal correlation. Hence, the temporal fluctuations of the obtained speckle pattern provide dynamic information about the blood flow. We developed a comprehensive simulation, combining the effects of Brownian motion, US and flow on the obtained speckle pattern. Photons trajectories within the tissue are generated using a Monte-Carlo based model. Then, the temporal changes in the optical path due to displacement of scattering centers are determined, and the corresponding interference pattern over time is derived. Finally, the light intensity autocorrelation function of a single speckle is calculated, from which the tissue decorrelation time is determined. The simulation's results are compared with in-vitro experiments, using a digital correlator, demonstrating decorrelation time prediction within the 95% confidence interval. This model may assist in the development of optical based methods for blood flow measurements and particularly, in methods using the acousto-optic effect.

  12. Variation of Red Blood Cell Distribution Width and Mean Platelet Volume after Moderate Endurance Exercise

    Directory of Open Access Journals (Sweden)

    Giuseppe Lippi

    2014-01-01

    Full Text Available Although physical exercise strongly influences several laboratory parameters, data about the hematological changes after medium distance running are scarce. We studied 31 middle-trained athletes (mean training regimen 217±32 min/week who performed a 21.1 km, half-marathon run. Blood samples were collected before the run, at the end, and 3 and 20 hours thereafter. The complete blood count was performed on Advia 2120 and included red blood cell (RBC, reticulocyte, and platelet counts; hemoglobin; mean corpuscular volume (MCV; mean corpuscular hemoglobin (MCH; reticulocyte haemoglobin content (Ret CHR; RBC distribution width (RDW, mean platelet volume (MPV. No significant variations were observed for MCH and Ret CHR. The RBC, reticulocyte, and hemoglobin values modestly decreased after the run. The MCV significantly increased at the end of running but returned to baseline 3 hours thereafter. The RDW constantly increased, reaching a peak 20 hours after the run. The platelet count and MPV both increased after the run and returned to baseline 3 hours thereafter. These results may have implications for definition of reference ranges and antidoping testing, and may also contribute to explaining the relationship between endurance exercise and mortality, since previous studies reported that RDW and MPV may be significantly associated with cardiovascular disease.

  13. Venous and fingertip blood to calculate plasma volume shift following exercise.

    Science.gov (United States)

    Knowlton, R G; Brown, D D; Hetzler, R K; Sikora, L M

    1990-12-01

    This study determined whether fingertip blood samples used to calculate percentage change in calculated plasma volume following exercise were in agreement with values obtained from venous blood samples. Twenty-five subjects engaged in two cycle ergometer exercises at 100 and 200 W, with percentage plasma volume shift (% PVS) determined after each from venous (VB) and fingertip (FT) blood. Values for % PVS were FT -6.25% compared with VB -8.04% (P less than 0.05), with the correlation between the two methods at r = 0.88. The following equation was established: corrected FT % PVS = (0.8662 * FT) - 2.625; SEE = 2.60%. In order to cross-validate this equation, fifteen additional subjects submitted to VB and FT. Corrected FT % PVS using the established equation resulted in a mean value of 9.53 compared with 10.53% for actual VB % PVS. Although these means were not significantly different, there was approximately a 25% chance that the corrected FT % PVS would be more than one standard error of estimate from the regression line. It was concluded that FT underestimates VB % PVS. However, when limited to group data, FT can be corrected to favorably represent VB % PVS following moderate to heavy cycle ergometer exercise.

  14. 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.

  15. Accurate blood flow measurements: are artificial tracers necessary?

    Directory of Open Access Journals (Sweden)

    Christian Poelma

    Full Text Available 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.

  16. 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.

  17. Optically measured microvascular blood flow contrast of malignant breast tumors.

    Directory of Open Access Journals (Sweden)

    Regine Choe

    Full Text Available Microvascular blood flow contrast is an important hemodynamic and metabolic parameter with potential to enhance in vivo breast cancer detection and therapy monitoring. Here we report on non-invasive line-scan measurements of malignant breast tumors with a hand-held optical probe in the remission geometry. The probe employs diffuse correlation spectroscopy (DCS, a near-infrared optical method that quantifies deep tissue microvascular blood flow. Tumor-to-normal perfusion ratios are derived from thirty-two human subjects. Mean (95% confidence interval tumor-to-normal ratio using surrounding normal tissue was 2.25 (1.92-2.63; tumor-to-normal ratio using normal tissues at the corresponding tumor location in the contralateral breast was 2.27 (1.94-2.66, and using normal tissue in the contralateral breast was 2.27 (1.90-2.70. Thus, the mean tumor-to-normal ratios were significantly different from unity irrespective of the normal tissue chosen, implying that tumors have significantly higher blood flow than normal tissues. Therefore, the study demonstrates existence of breast cancer contrast in blood flow measured by DCS. The new, optically accessible cancer contrast holds potential for cancer detection and therapy monitoring applications, and it is likely to be especially useful when combined with diffuse optical spectroscopy/tomography.

  18. Blood-Pressure Measuring System Gives Accurate Graphic Output

    Science.gov (United States)

    1965-01-01

    The problem: To develop an instrument that will provide an external (indirect) measurement of arterial blood pressure in the form of an easily interpreted graphic trace that can be correlated with standard clinical blood-pressure measurements. From sphygmograms produced by conventional sphygmographs, it is very difficult to differentiate the systolic and diastolic blood-pressure pulses and to correlate these indices with the standard clinical values. It is nearly impossible to determine these indices when the subject is under physical or emotional stress. The solution: An electronic blood-pressure system, basically similar to conventional ausculatory sphygmomanometers, employing a standard occluding cuff, a gas-pressure source, and a gas-pressure regulator and valve. An electrical output transducer senses cuff pressure, and a microphone positioned on the brachial artery under the occluding cuff monitors the Korotkoff sounds from this artery. The output signals present the conventional systolic and diastolic indices in a clear, graphical display. The complete system also includes an electronic timer and cycle-control circuit.

  19. Automatic measurement of orbital volume in unilateral coronal synostosis

    DEFF Research Database (Denmark)

    Dahl, Vedrana Andersen; Einarsson, Gudmundur; Darvann, Tron Andre;

    2016-01-01

    Premature fusion of the coronal suture on one side of the calvaria (unilateral coronal synostosis, UCS) results in asymmetric craniofacial development and the deformation of the orbits. Often this necessitates surgery, where CT scanning is employed to obtain measures of the bony orbit...... segmentations. We obtain similar measures, as well as high Dice scores, compared to the experts. The run time for the proposed approach with a prototype implementation is around 3 minutes on a standard laptop, making the method suitable for rapid evaluation of orbital volume in UCS....

  20. Volume Tracking: A new method for quantitative assessment and visualization of intracardiac blood flow from three-dimensional, time-resolved, three-component magnetic resonance velocity mapping

    Directory of Open Access Journals (Sweden)

    Arheden Håkan

    2011-04-01

    Full Text Available Abstract Background Functional and morphological changes of the heart influence blood flow patterns. Therefore, flow patterns may carry diagnostic and prognostic information. Three-dimensional, time-resolved, three-directional phase contrast cardiovascular magnetic resonance (4D PC-CMR can image flow patterns with unique detail, and using new flow visualization methods may lead to new insights. The aim of this study is to present and validate a novel visualization method with a quantitative potential for blood flow from 4D PC-CMR, called Volume Tracking, and investigate if Volume Tracking complements particle tracing, the most common visualization method used today. Methods Eight healthy volunteers and one patient with a large apical left ventricular aneurysm underwent 4D PC-CMR flow imaging of the whole heart. Volume Tracking and particle tracing visualizations were compared visually side-by-side in a visualization software package. To validate Volume Tracking, the number of particle traces that agreed with the Volume Tracking visualizations was counted and expressed as a percentage of total released particles in mid-diastole and end-diastole respectively. Two independent observers described blood flow patterns in the left ventricle using Volume Tracking visualizations. Results Volume Tracking was feasible in all eight healthy volunteers and in the patient. Visually, Volume Tracking and particle tracing are complementary methods, showing different aspects of the flow. When validated against particle tracing, on average 90.5% and 87.8% of the particles agreed with the Volume Tracking surface in mid-diastole and end-diastole respectively. Inflow patterns in the left ventricle varied between the subjects, with excellent agreement between observers. The left ventricular inflow pattern in the patient differed from the healthy subjects. Conclusion Volume Tracking is a new visualization method for blood flow measured by 4D PC-CMR. Volume Tracking

  1. Minimal volume regulation after shrinkage of red blood cells from five species of reptiles

    DEFF Research Database (Denmark)

    Kristensen, Karina; Berenbrink, Michael; Koldkjær, Pia

    2008-01-01

    Red blood cells (RBCs) from most vertebrates restore volume upon hypertonic shrinkage and the mechanisms underlying this regulatory volume increase (RVI) have been studied extensively in these cells. Despite the phylogenetically interesting position of reptiles, very little is known about their red...... cell function. The present study demonstrates that oxygenated RBCs in all major groups of reptiles exhibit no or a very reduced RVI upon ~ 25% calculated hyperosmotic shrinkage. Thus, RBCs from the snakes Crotalus durissus and Python regius, the turtle Trachemys scripta and the alligator Alligator...... was not characterized. It seems, therefore, that the RVI response based on NHE activation was lost among the early sauropsids that gave rise to modern reptiles and birds, while it was retained in mammals. An RVI response has then reappeared in birds, but based on activation of the NKCC. Alternatively, the absence...

  2. Closed versus open endotracheal suctioning in preterm infants: effects on cerebral oxygenation and blood volume.

    Science.gov (United States)

    Mosca, F A; Colnaghi, M; Lattanzio, M; Bray, M; Pugliese, S; Fumagalli, M

    1997-01-01

    The aim of our study was to compare, using near-infrared spectroscopy (NIRS), the effects on cerebral intracellular oxygenation and cerebral blood volume (CBV) of closed endotracheal suctioning (CS), which permits continuous ventilation of the patient, with open endotracheal suctioning (OS), which requires disconnection from the ventilator. Eleven preterm infants were studied. Each patient underwent one CS, followed, after 60 min, by one OS, or vice versa, three times during the same day. Modifications in CBV and oxidized cytochrome oxidase (CytO2) were continuously detected by NIRS; arterial oxygen saturation (SaO2) heart rate (HR), transcutaneous carbon dioxide tension and mean arterial blood pressure were simultaneously recorded. Significant reductions in HR and SaO2 were observed following OS; the magnitude and duration of these negative effects of suctioning were significantly reduced with CS. In addition, the decrease in CBV was more pronounced than following CS. No changes in CytO2 concentration were seen.

  3. Smart fast blood counting of trace volumes of body fluids from various mammalian species using a compact custom-built microscope cytometer (Conference Presentation)

    Science.gov (United States)

    Smith, Zachary J.; Gao, Tingjuan; Lin, Tzu-Yin; Carrade-Holt, Danielle; Lane, Stephen M.; Matthews, Dennis L.; Dwyre, Denis M.; Wachsmann-Hogiu, Sebastian

    2016-03-01

    Cell counting in human body fluids such as blood, urine, and CSF is a critical step in the diagnostic process for many diseases. Current automated methods for cell counting are based on flow cytometry systems. However, these automated methods are bulky, costly, require significant user expertise, and are not well suited to counting cells in fluids other than blood. Therefore, their use is limited to large central laboratories that process enough volume of blood to recoup the significant capital investment these instruments require. We present in this talk a combination of a (1) low-cost microscope system, (2) simple sample preparation method, and (3) fully automated analysis designed for providing cell counts in blood and body fluids. We show results on both humans and companion and farm animals, showing that accurate red cell, white cell, and platelet counts, as well as hemoglobin concentration, can be accurately obtained in blood, as well as a 3-part white cell differential in human samples. We can also accurately count red and white cells in body fluids with a limit of detection ~3 orders of magnitude smaller than current automated instruments. This method uses less than 1 microliter of blood, and less than 5 microliters of body fluids to make its measurements, making it highly compatible with finger-stick style collections, as well as appropriate for small animals such as laboratory mice where larger volume blood collections are dangerous to the animal's health.

  4. Real-time contrast-enhanced ultrasound determination of microvascular blood volume in abdominal subcutaneous adipose tissue in man. Evidence for adipose tissue capillary recruitment

    DEFF Research Database (Denmark)

    Tobin, L; Simonsen, L; Bülow, J

    2010-01-01

    the basic and postprandial microvascular volume in adipose tissue using real-time contrast-enhanced ultrasound (CEU) imaging in healthy normal weight subjects. In nine subjects, CEU was performed in abdominal subcutaneous adipose tissue and in the underlying skeletal muscle after a bolus injection...... of ultrasound contrast agent to establish the reproducibility of the technique. In nine subjects, the effect of an oral glucose load on blood flow and microvascular volume was measured in abdominal subcutaneous adipose tissue and forearm skeletal muscle. ¹³³Xe washout and venous occlusion strain......-gauge plethysmography was used to measure the adipose tissue and forearm blood flow, respectively. Ultrasound signal intensity of the first plateau phases was 27 ± dB in the abdominal subcutaneous adipose tissue and 18 ± 2 dB (P muscle. The reproducibility of the measurements was good...

  5. Inconsistent detection of changes in cerebral blood volume by near infrared spectroscopy in standard clinical tests.

    Science.gov (United States)

    Canova, D; Roatta, S; Bosone, D; Micieli, G

    2011-06-01

    The attractive possibility of near infrared spectroscopy (NIRS) to noninvasively assess cerebral blood volume and oxygenation is challenged by the possible interference from extracranial tissues. However, to what extent this may affect cerebral NIRS monitoring during standard clinical tests is ignored. To address this issue, 29 healthy subjects underwent a randomized sequence of three maneuvers that differently affect intra- and extracranial circulation: Valsalva maneuver (VM), hyperventilation (HV), and head-up tilt (HUT). Putative intracranial ("i") and extracranial ("e") NIRS signals were collected from the forehead and from the cheek, respectively, and acquired together with cutaneous plethysmography at the forehead (PPG), cerebral blood velocity from the middle cerebral artery, and arterial blood pressure. Extracranial contribution to cerebral NIRS monitoring was investigated by comparing Beer-Lambert (BL) and spatially resolved spectroscopy (SRS) blood volume indicators [the total hemoglobin concentration (tHb) and the total hemoglobin index, (THI)] and by correlating their changes with changes in extracranial circulation. While THIe and tHbe generally provided concordant indications, tHbi and THIi exhibited opposite-sign changes in a high percentage of cases (VM: 46%; HV: 31%; HUT: 40%). Moreover, tHbi was correlated with THIi only during HV (P < 0.05), not during VM and HUT, while it correlated with PPG in all three maneuvers (P < 0.01). These results evidence that extracranial circulation may markedly affect BL parameters in a high percentage of cases, even during standard clinical tests. Surface plethysmography at the forehead is suggested as complementary monitoring helpful in the interpretation of cerebral NIRS parameters.

  6. Improved technique for blood flow velocity measurement using Doppler effect

    Science.gov (United States)

    Valadares Oliveira, Eduardo J.; Nantes Button, Vera L. d. S.; Maia, Joaquim M.; Costa, Eduardo T.

    2002-04-01

    The Doppler velocimeter developed allows to determine the angle between the ultrasonic beam and the velocity vector of the flow, and to calculate the precise blood flow in a vessel. Four piezoelectric transducers constitute the Doppler velocimeter. Three of these transducers are positioned to form an equilateral triangle (base of a pyramid). When these transducers move simultaneously, backward or forward from the initial position, the emitted ultrasonic beams focalize on a position (peak of the pyramid) closer or farther from the transducers faces, according to the depth of the vessel where we intend to measure de flow. The angle between the transducers allows adjusting the height of this pyramid and the position of the focus (where the three beams meet). A forth transducer is used to determine the diameter of the vessel and monitor the position of the Doppler velocimeter relative to the vessel. Simulation results showed that with this technique is possible to accomplish precise measurement of blood flow.

  7. Positron emission tomography in cerebrovascular disease: The relationship between regional cerebral blood flow, blood volume and oxygen metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Herold, S.

    1985-03-01

    Positron emission tomography in cerebrovascular disease has demonstrated the importance of the relationship between regional cerebral blood flow and the cerebral metabolic activity. In acute stroke it has been found that within the first hours after the onset of symptoms cerebral blood flow in the affected area is more depressed than cerebral oxygen utilisation. This relative preservation of oxygen utilisation results from an increase in the oxygen extraction ratio far above its normal value. However, the oxygen extraction fraction subsequently falls in the following days indicating the transition from a situation of possibly reversible ischaemia to irreversible infarction. In patients with carotid occlusive disease an increase in the oxygen extraction ratio has been observed only in very few cases. It has been shown, however, that at an earlier stage the relationship between CBF and CBV (as CBF/CBV-ratio) provides a sensitive measure of diminished perfusion pressure which could be helpful for the selection of patients for EC-IC bypass surgery. In patients with sickle cell anaemia it has been found that oxygen delivery to the brain is maintained by an increase in cerebral blood flow, whereas the oxygen extraction ratio is not increased despite the presence of a low oxygen affinity haemoglobin. Preliminary observations in classical migraine suggest an ischaemic situation during the attack.

  8. Measurement and analysis of grain boundary grooving by volume diffusion

    Science.gov (United States)

    Hardy, S. C.; Mcfadden, G. B.; Coriell, S. R.; Voorhees, P. W.; Sekerka, R. F.

    1991-01-01

    Experimental measurements of isothermal grain boundary grooving by volume diffusion are carried out for Sn bicrystals in the Sn-Pb system near the eutectic temperature. The dimensions of the groove increase with a temporal exponent of 1/3, and measurement of the associated rate constant allows the determination of the product of the liquid diffusion coefficient D and the capillarity length Gamma associated with the interfacial free energy of the crystal-melt interface. The small-slope theory of Mullins is generalized to the entire range of dihedral angles by using a boundary integral formulation of the associated free boundary problem, and excellent agreement with experimental groove shapes is obtained. By using the diffusivity measured by Jordon and Hunt, the present measured values of Gamma are found to agree to within 5 percent with the values obtained from experiments by Gunduz and Hunt on grain boundary grooving in a temperature gradient.

  9. The influence of urine volume on body impedance measurement.

    Science.gov (United States)

    Hong, K H; Park, K S

    2008-01-01

    Bio-signal has some characteristics that the signal is so weak. So, it is good that the factors to influence measured electrical signal are eliminated as much as they can. So, in this paper we will show the influence of urine in bladder on measuring human body impedance. Human urine has different conductivity from other human tissues. Therefore, if the volume of the urine changed, the measured body impedance data also changed.So, in this paper, we will show the influence of urine in bladder with foot-to-foot and thigh-to-thigh current paths. As a result, if the current flows through human bladder, the influence of urine in the bladder must be considered when the body impedance is measured

  10. Laser-induced incandescence: Towards quantitative soot volume fraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tzannis, A.P.; Wienbeucker, F.; Beaud, P.; Frey, H.-M.; Gerber, T.; Mischler, B.; Radi, P.P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Laser-Induced Incandescence has recently emerged as a versatile tool for measuring soot volume fraction in a wide range of combustion systems. In this work we investigate the essential features of the method. LII is based on the acquisition of the incandescence of soot when heated through a high power laser pulse. Initial experiments have been performed on a model laboratory flame. The behaviour of the LII signal is studied experimentally. By applying numerical calculations we investigate the possibility to obtain two-dimensional soot volume fraction distributions. For this purpose a combination of LII with other techniques is required. This part is discussed in some extent and the future work is outlined. (author) 4 figs., 3 refs.

  11. Gamma ray densitometry techniques for measuring of volume fractions

    Energy Technology Data Exchange (ETDEWEB)

    Affonso, Renato Raoni Werneck; Silva, Ademir Xavier da; Salgado, Cesar Marques, E-mail: raoniwa@yahoo.com.br, E-mail: ademir@nuclear.ufrj.br, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Knowledge of the volume fraction in a multiphase flow is of key importance in predicting the performance of many systems and processes. It is therefore an important parameter to characterize such flows. In the context of nuclear techniques, the gamma ray densitometry is promising and this is due to its non-invasive characteristics and very reliable results. It is used in several applications for multiphase flows (water-oil-air), which are employed tools such as: computational fluid dynamics, artificial neural networks and statistical methods of radiation transport, such as the Monte Carlo method. Based on the gamma radiation techniques for measurements of volume fractions, the aim of this paper is to present several techniques developed for this purpose. (author)

  12. Characteristic prefrontal blood volume patterns when imaging body type, high-calorie food, and mother-child attachment in childhood anorexia nervosa: A near infrared spectroscopy study.

    Science.gov (United States)

    Nagamitsu, Shinichiro; Yamashita, Fumiko; Araki, Yuko; Iizuka, Chiho; Ozono, Shuichi; Komatsu, Hiroko; Ohya, Takashi; Yamashita, Yushiro; Kakuma, Tatsuyuki; Tsuda, Akira; Matsuishi, Toyojiro

    2010-02-01

    The aim of this study was to investigate the prefrontal activation in childhood anorexia nervosa (AN) patients when imaging symptom-provocative factors such as body type, high-calorie food, and attachment between mother and child. The prefrontal activations during each task, in terms of blood volume changes, were measured by near infrared spectroscopy. Twelve females with childhood AN (mean age, 14.4 years old) and 13 age-matched healthy female controls (mean age, 14.3 years old) participated in this study. Both groups showed increased prefrontal blood volume when viewing images of each symptom-provocative factor. Unexpectedly, there was no significant difference in the prefrontal blood volume increases between the control group and the childhood AN group when viewing images of slender and obese body types and high-calorie food. On the other hand, images of mother-child attachment resulted in significantly greater increases in prefrontal blood volume in the childhood AN group than in the control group. These results indicated that prefrontal activation in AN might be associated with imaging attachment between mother and child, but not associated with imaging body type or high-calorie food.

  13. Quantitating error in blood flow measurements with radioactive microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Austin, R.E. Jr.; Hauck, W.W.; Aldea, G.S.; Flynn, A.E.; Coggins, D.L.; Hoffman, J.I.

    1989-07-01

    Accurate determination of the reproducibility of measurements using the microsphere technique is important in assessing differences in blood flow to different organs or regions within organs, as well as changes in perfusion under various experimental conditions. The sources of error of the technique are briefly reviewed. In addition, we derived a method for combining quantifiable sources of error into a single estimate that was evaluated experimentally by simultaneously injecting eight or nine sets of microspheres (each with a different radionuclide label) into four anesthetized dogs. Each nuclide was used to calculate blood flow in 145-190 myocardial regions. We compared each flow determination (using a single nuclide label) with a weighted mean for the piece (based on the remaining nuclides). The difference was defined as ''measured'' error. In all, there were a total of 5,975 flow observations. We compared measured error with theoretical estimates based on the Poisson error of radioactive disintegration and microsphere entrapment, nuclide separation error, and reference flow error. We found that combined estimates based on these sources completely accounted for measured error in the relative distribution of microspheres. In addition, our estimates of the error in measuring absolute flows (which were established using microsphere reference samples) slightly, but significantly, underestimated measured error in absolute flow.

  14. Salt and fluid loading: effects on blood volume and exercise performance.

    Science.gov (United States)

    Mora-Rodriguez, Ricardo; Hamouti, Nassim

    2012-01-01

    During prolonged exercise, fluid and salt losses through sweating reduce plasma volume which leads to heart rate drift in association with hyperthermia and reductions in performance. Oral rehydration with water reduces the loss of plasma volume and lessens heart rate drift and hyperthermia. Moreover, the inclusion of sodium in the rehydration solution to levels that double those in sweat (i.e., around 90 mmol/l Na(+)) restores plasma volume when ingested during exercise, and expands plasma volume if ingested pre-exercise. Pre-exercise salt and fluid ingestion with the intention of expanding plasma volume has received an increasing amount of attention in the literature in recent years. In four studies, pre-exercise salt and fluid ingestion improved performance, measured as time to exhaustion, either during exercise in a thermoneutral or in a hot environment. While in a hot environment, the performance improvements were linked to lowering of core temperatures and heart rate, the reasons for the improved performance in a thermoneutral environment remain unclear. However, when ingesting pre-exercise saline solutions above 0.9% (i.e., > 164 mmol/l Na(+)), osmolality and plasma sodium increase and core temperature remain at dehydration levels. Thus, too much salt counteracts the beneficial effects of plasma volume expansion on heat dissipation and hence in performance. In summary, the available literature suggests that pre-exercise saline ingestion with concentrations not over 164 mmol/l Na(+) is an ergogenic aid for subsequent prolonged exercise in a warm or thermoneutral environment.

  15. Pulsed photoacoustic Doppler flow measurements in blood-mimicking phantoms

    Science.gov (United States)

    Brunker, J.; Beard, P.

    2011-03-01

    The feasibility of making spatially resolved measurements of blood flow using pulsed photoacoustic Doppler techniques has been explored. Doppler time shifts were quantified via cross-correlation of pairs of photoacoustic waveforms generated within a blood-simulating phantom using pairs of laser light pulses. The photoacoustic waves were detected using a focussed or planar PZT ultrasound transducer. For each flow measurement, a series of 100 waveform pairs was collected. Previous data processing methods involved rejection of poorly correlated waveform pairs; the modal velocity value and standard deviation were then extracted from the selected distribution of velocity measurements. However, the data selection criteria used in this approach is to some extent arbitrary. A new data analysis protocol, which involves averaging the 100 cross-correlation functions and thus uses all of the measured data, has been designed in order to prevent exclusion of outliers. This more rigorous approach has proved effective for quantifying the linear motion of micron-scale absorbers imprinted on an acetate sheet moving with velocities in the range 0.14 to 1.25 ms-1. Experimental parameters, such as the time separation between the laser pulses and the transducer frequency response, were evaluated in terms of their effect on the accuracy, resolution and range of measurable velocities. The technique was subsequently applied to fluid phantoms flowing at rates less than 5 mms-1 along an optically transparent tube. Preliminary results are described for three different suspensions of phenolic resin microspheres, and also for whole blood. Velocity information was obtained even under non-optimal conditions using a low frequency transducer and a low pulse repetition frequency. The distinguishing advantage of pulsed rather than continuous-wave excitation is that spatially resolved velocity measurements can be made. This offers the prospect of mapping flow within the microcirculation and thus

  16. Dissociation of Blood Volume and Flow in Regulation of Salt and Water Balance in Burn Patients,

    Science.gov (United States)

    1991-09-01

    arterial capacity, which is underfilled at sites of lower than in the patients in the present study (276 versus hormone control. 286 mosm/kg). The serum...well as looking at given ability to concentrate their urine and lower their voiding volume 02 consumption measured by indirect calorimetry. at night, I

  17. Local blood flow measured by fluorescence excitation of nonradioactive microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Y.; Payne, B.D.; Aldea, G.S.; McWatters, C.; Husseini, W.; Mori, H.; Hoffman, J.I.; Kaufman, L. (Univ. of California, San Francisco (USA))

    1990-05-01

    An X-ray fluorescence system with low Compton background and high counting efficiency was developed to measure regional blood flow with nonradioactive microspheres. The performance of the system was tested in vitro by counting mixed aqueous solutions of either Mo, Ag, and I; Nb, Ag, and Ba; or Zr, Mo, Rh, Ag, Sn, I, and Ba, as well as a mixture of Ag and Ba nonradioactive microspheres. Mixtures containing 2-20 ppm of each element were counted for 10 min by the fluorescence system, and the individual elements in mixtures of three to seven nonradioactive elements were measured with high accuracy. The best counting statistics were obtained for Ag. For 10-min counts, the system measures as few as 120 Ag microspheres with 30% standard deviation but measures 800 Ag microspheres per sample with 3.6% standard deviation. We compared regional myocardial blood flows determined simultaneously by fluorescence and radioactive microsphere methods; the latter samples were counted by a 3-in. NaI (Tl) well detector and pulse-height analyzer. The radioactive and nonradioactive measurements showed good correlations.

  18. 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

  19. Measurements of the volume scattering function in a coastal environment

    Science.gov (United States)

    Berthon, Jean-François; Lee, Michael; Shybanov, Eugeny; Zibordi, Giuseppe

    2007-04-01

    The Volume Scattering Function (VSF) is an essential variable in the context of marine radiative transfer modeling and of the inversion of ocean colour remote sensing data. However, an important lack of knowledge on the VSF natural variability affects the present models, in particular for the coastal environment. Measurements of the Volume Scattering Function between 0.6° and 177.3° with an angular resolution of 0.3° were performed in the northern coastal Adriatic Sea onboard an oceanographic platform in October 2004 using a prototype instrument. Observed differences with the commonly used Petzold's functions are significant, in particular for the "open ocean" and "coastal" types in the backward directions. The use of an empirical relationship for the derivation of b b(λ) from a unique measurement of β(ψ,λ) at ψ=140 for the Hydroscat-6 was validated for this coastal site at that season. Finally, the use of the Kopelevich VSF model together with a measurement of b p(λ) at λ=555 nm allowed the reconstruction of the VSF to within about 35%.

  20. Integrated Optofluidic Chip for Low-Volume Fluid Viscosity Measurement

    Directory of Open Access Journals (Sweden)

    Tie Yang

    2017-02-01

    Full Text Available In the present work, an integrated optofluidic chip for fluid viscosity measurements in the range from 1 mPa·s to 100 mPa·s is proposed. The device allows the use of small sample volumes (<1 µL and the measurement of viscosity as a function of temperature. Thanks to the precise control of the force exerted on dielectric spheres by optical beams, the viscosity of fluids is assessed by comparing the experimentally observed movement of dielectric beads produced by the optical forces with that expected by numerical calculations. The chip and the developed technique are validated by analyzing several fluids, such as Milli-Q water, ethanol and water–glycerol mixtures. The results show a good agreement between the experimental values and those reported in the literature. The extremely reduced volume of the sample required and the high flexibility of this technique make it a good candidate for measuring a wide range of viscosity values as well as for the analysis of nonlinear viscosity in complex fluids.

  1. Blood pressure measurement: lessons learned from our ancestors.

    Science.gov (United States)

    Karamanou, Marianna; Papaioannou, Theodore G; Tsoucalas, Gregory; Tousoulis, Dimitris; Stefanadis, Christodoulos; Androutsos, George

    2015-01-01

    The profound observations of William Harvey (1578-1657), in blood circulation and the progress of physical science laid the foundation for the development of the Iatrophysical School that contributed to the evolution of clinical sphygmomanometry. The pioneer work of Reverend Stephen Hales (1677-1761) demonstrated the dynamics of the vascular system. One century later the French physician Jean-Léonard-Marie Poiseuille (1797-1867) invented a U-tube mercury manometer and in 1860 the physiologist Etienne- Jules Marey (1830-1904) devised the first portable sphygmograph for recording the pulse wave. The non-invasive techniques of blood pressure measurement were completed by Scipione Riva-Rocci (1896-1937) sphygmomanometer and the description of "Korotkov sounds" by the Russian surgeon Nikolai- Sergeyevich Korotkov (1874-1920).

  2. Pressure Gradient Estimation Based on Ultrasonic Blood Flow Measurement

    Science.gov (United States)

    Nitta, Naotaka; Homma, Kazuhiro; Shiina, Tsuyoshi

    2006-05-01

    Mechanical load to the blood vessel wall, such as shear stress and pressure, which occurs in blood flow dynamics, contribute greatly to plaque rupture in arteriosclerosis and to biochemical activation of endothelial cells. Therefore, noninvasive estimations of these mechanical loads are able to provide useful information for the prevention of vascular diseases. Although the pressure is the dominant component of mechanical load, for practical purposes, the pressure gradient is also often important. So far, we have investigated the estimation of the kinematic viscosity coefficient using a combination of the Navier-Stokes equations and ultrasonic velocity measurement. In this paper, a method for pressure gradient estimation using the estimated kinematic viscosity coefficient is proposed. The validity of the proposed method was investigated on the basis of the analysis with the data obtained by computer simulation and a flow phantom experiment. These results revealed that the proposed method can provide a valid estimation of the pressure gradient.

  3. Blood Volume: Importance and Adaptations to Exercise Training, Environmental Stresses and Trauma/Sickness

    Science.gov (United States)

    Sawka, Michael N.; Convertino, Victor A.; Eichner, E. Randy; Schnieder, Suzanne M.; Young, Andrew J.

    2000-01-01

    This paper reviews the influence of several perturbations (physical exercise, heat stress, terrestrial altitude, microgravity, and trauma/sickness) on adaptations of blood volume (BV), erythrocyte volume (EV), and plasma volume (PV). Exercise training can induced BV expansion; PV expansion usually occurs immediately, but EV expansion takes weeks. EV and PV expansion contribute to aerobic power improvements associated with exercise training. Repeated heat exposure induces PV expansion but does not alter EV. PV expansion does not improve thermoregulation, but EV expansion improves thermoregulation during exercise in the heat. Dehydration decreases PV (and increases plasma tonicity) which elevates heat strain and reduces exercise performance. High altitude exposure causes rapid (hours) plasma loss. During initial weeks at altitude, EV is unaffected, but a gradual expansion occurs with extended acclimatization. BV adjustments contribute, but are not key, to altitude acclimatization. Microgravity decreases PV and EV which contribute to orthostatic intolerance and decreased exercise capacity in astronauts. PV decreases may result from lower set points for total body water and central venous pressure, which EV decrease bay result form increased erythrocyte destruction. Trauma, renal disease, and chronic diseases cause anemia from hemorrhage and immune activation, which suppressions erythropoiesis. The re-establishment of EV is associated with healing, improved life quality, and exercise capabilities for these injured/sick persons.

  4. A low-cost, small volume circuit for autologous blood normothermic perfusion of rabbit organs.

    Science.gov (United States)

    Worner, Murray; Poore, Samuel; Tilkorn, Daniel; Lokmic, Zerina; Penington, Anthony J

    2014-04-01

    We have designed a laboratory extracorporeal normothermic blood perfusion system for whole organs (e.g., kidney) that achieves pulsatile flow, low levels of hemolysis, and a blood priming volume of 60 mL or less. Using this uniquely designed extracorporeal circuit, we have achieved perfusion of two isolated ex vivo constructs. In the first experiment, we successfully perfused a rabbit epigastric flap based on the femoral vessels. In the second experiment, we were able to perfuse the isolated rabbit kidney for 48 h (range for all kidneys was 12-48 h) with excellent urine output, normal arterial blood gasses at 24 h, and normal ex vivo kidney histology at the conclusion of the experiments. These parameters have not been achieved before with any known or previously published laboratory extracorporeal circuits. The study has implications for prolonged organ perfusion prior to transplantation and for tissue engineering of vascularized tissues, such as by the perfusion of decellularized organs.

  5. Analysis of ochratoxin A in dried blood spots - Correlation between venous and finger-prick blood, the influence of hematocrit and spotted volume.

    Science.gov (United States)

    Osteresch, Bernd; Cramer, Benedikt; Humpf, Hans-Ulrich

    2016-05-01

    We report the improvement of a method for the detection of ochratoxin A (OTA) and its thermal degradation product 2'R-ochratoxin A in dried blood spots (DBS) by high performance liquid chromatographic (HPLC) tandem mass spectrometry (MS/MS). The DBS technique was advanced for the analysis of these two compounds in DBS with unknown amounts of blood as well as varying hematocrit values. Furthermore the comparability of venous vs. capillary blood was investigated. Human whole blood samples were spotted, dried, and extracted with a solvent consisting of acetone, acetonitrile and water for analysis by HPLC-MS/MS. Quantification was carried out by stable isotope labelled internal standards. Blood samples of volunteers (n=50) were used to further optimize and simplify the procedure. Ochratoxin A and 2'R-ochratoxin A concentrations found in the entire spots (approx. 100 μL blood) were compared with punched DBS discs of 8.8mm size containing approximately 20 μL blood. As a result the amounts of both toxins in a punched 8.8mm disc correlate well with the entire DBS. Also the use of capillary blood from finger-pricks versus venous blood was evaluated. The analyte levels correlate as well indicating that the less invasive finger-prick sampling gives also reliable results. The influence of hematocrit was investigated in a range of 25-55% according to the hematocrit in the used real blood samples (34-46% hematocrit). However no significant hematocrit effect was observed for the utilized real blood samples. Moreover different blood volumes were spotted and punched as a minimal spot size is usually recommended for accurate analysis. In this experiment finger-prick samples typically consist of about 90 μL blood. Therefore spots of 75, 100 and 125 μL blood were prepared and analyzed. Similar to the hematocrit effect, no considerable influence was observed.

  6. Effect of volume loading on the Frank-Starling relation during reductions in central blood volume in heat-stressed humans.

    Science.gov (United States)

    Bundgaard-Nielsen, M; Wilson, T E; Seifert, T; Secher, N H; Crandall, C G

    2010-09-01

    During reductions in central blood volume while heat stressed, a greater decrease in stroke volume (SV) for a similar decrease in ventricular filling pressure, compared to normothermia, suggests that the heart is operating on a steeper portion of a Frank-Starling curve. If so, volume loading of heat-stressed individuals would shift the operating point to a flatter portion of the heat stress Frank-Starling curve thereby attenuating the reduction in SV during subsequent decreases in central blood volume. To investigate this hypothesis, right heart catheterization was performed in eight males from whom pulmonary capillary wedge pressure (PCWP), central venous pressure and SV (via thermodilution) were obtained while central blood volume was reduced via lower-body negative pressure (LBNP) during normothermia, whole-body heating (increase in blood temperature 1 degrees C), and during whole-body heating after intravascular volume expansion. Volume expansion was accomplished by administration of a combination of a synthetic colloid (HES 130/0.4, Voluven) and saline. Before LBNP, SV was not affected by heating (122 +/- 30 ml; mean +/- s.d.) compared to normothermia (110 +/- 20 ml; P = 0.06). However, subsequent volume loading increased SV to 143 +/- 29 ml (P = 0.003). LBNP provoked a larger decrease in SV relative to the decrease in PCWP during heating (8.6 +/- 1.9 ml mmHg(1)) compared to normothermia (4.5 +/- 3.0 ml mmHg(1), P = 0.02). After volume loading while heat stressed, the reduction in the SV to PCWP ratio during LBNP was comparable to that observed during normothermia (4.8 +/- 2.3 ml mmHg(1); P = 0.78). These data support the hypothesis that a Frank-Starling mechanism contributes to compromised blood pressure control during simulated haemorrhage in heat-stressed individuals, and extend those findings by showing that volume infusion corrects this deficit by shifting the operating point to a flatter portion of the heat stress Frank-Starling curve.

  7. Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution

    Science.gov (United States)

    Seymour, Roger S.; Bosiocic, Vanya; Snelling, Edward P.

    2016-08-01

    The evolution of human cognition has been inferred from anthropological discoveries and estimates of brain size from fossil skulls. A more direct measure of cognition would be cerebral metabolic rate, which is proportional to cerebral blood flow rate (perfusion). The hominin cerebrum is supplied almost exclusively by the internal carotid arteries. The sizes of the foramina that transmitted these vessels in life can be measured in hominin fossil skulls and used to calculate cerebral perfusion rate. Perfusion in 11 species of hominin ancestors, from Australopithecus to archaic Homo sapiens, increases disproportionately when scaled against brain volume (the allometric exponent is 1.41). The high exponent indicates an increase in the metabolic intensity of cerebral tissue in later Homo species, rather than remaining constant (1.0) as expected by a linear increase in neuron number, or decreasing according to Kleiber's Law (0.75). During 3 Myr of hominin evolution, cerebral tissue perfusion increased 1.7-fold, which, when multiplied by a 3.5-fold increase in brain size, indicates a 6.0-fold increase in total cerebral blood flow rate. This is probably associated with increased interneuron connectivity, synaptic activity and cognitive function, which all ultimately depend on cerebral metabolic rate.

  8. Measurements Of Coronary Mean Transit Time And Myocardial Tissue Blood Flow By Deconvolution Of Intravasal Tracer Dilution Curves

    Science.gov (United States)

    Korb, H.; Hoeft, A.; Hellige, G.

    1984-10-01

    Previous studies have shown that intramyocardial blood volume does not vary to a major extent even during extreme variation of hemodynamics and coronary vascular tone. Based on a constant intramyocardial blood volume it is therefore possible to calculate tissue blood flow from the mean transit time of an intravascular tracer. The purpose of this study was to develop a clinically applicable method for measurement of coronary blood flow. The new method was based on indocyanine green, a dye which is bound to albumin and intravasally detectable by means of a fiberoptic catheter device. One fiberoptic catheter was placed in the aortic root and another in the coronary sinus. After central venous dye injection the resulting arterial and coronary venous dye dilution curves were processed on-line by a micro-computer. The mean transit time as well as myocardial blood flow were calculated from the step response function of the deconvoluted arterial and coronary venous signals. Reference flow was determined with an extracorporeal electromagnetic flowprobe within a coronary sinus bypass system. 38 steady states with coronary blood flow ranging from 49 - 333 ml/min*100g were analysed in 5 dogs. Mean transit times varied from 2.9 to 16.6 sec. An average intracoronary blood volume of 13.9 -7 1.8 m1/100g was calculated. The correlation between flow determined by the dye dilution technique and flow measured with the reference method was 0.98. According to these results determination of coronary blood flow with a double fiberoptic system and indocyanine green should be possible even under clinical conditions. Furthermore, the arterial and coronary venous oxygen saturation can be monitored continuously by the fiberoptic catheters. Therefore, additional information about the performance of the heart such as myocardial oxygen consumption and myocardial efficiency is available with the same equipment.

  9. Laser Doppler flowmetry to measure changes in cerebral blood flow.

    Science.gov (United States)

    Sutherland, Brad A; Rabie, Tamer; Buchan, Alastair M

    2014-01-01

    Laser Doppler flowmetry (LDF) is a method by which relative cerebral blood flow (CBF) of the cortex can be measured. Although the method is easy to employ, LDF only measures relative CBF, while absolute CBF cannot be quantified. LDF is useful for investigating CBF changes in a number of different applications including neurovascular and stroke research. This chapter will prepare the reader for rodent experiments using LDF with two preparations. The closed skull preparation can be used to monitor CBF with an intact skull, but in adult rats, thinning of the skull is required to obtain an accurate cortical CBF signal. The open skull preparation requires a craniotomy to expose the surface of the brain and the LDF probe is held close to the surface to measure cerebral perfusion.

  10. Patients' experiences and opinions of home blood pressure measurement.

    Science.gov (United States)

    Rickerby, J; Woodward, J

    2003-07-01

    Regular measurement of the blood pressure (BP) is necessary to monitor the treatment of hypertension, and self-measurement is one technique of obtaining such measurements. The aim of this study was to investigate the experiences of individuals who have carried out home BP measurement. A qualitative method using semistructured interviews was used with 13 subjects. These were adults with hypertension who had previous experience of measuring their own BP, and were recruited to the study from one UK general medical practice. Interviews were recorded and transcribed, and data from the interviews have been analysed using phenomenological principles and identifying 'meaning units.' The findings suggest that participants were willing to carry out home measurements and several were pleased to have been asked to be more involved in their own management. All found the technique straightforward. Most noted marked variability in the day-to-day BP measurements. Several exhibited the 'white coat' phenomenon (spuriously raised BP in certain settings only). Some participants showed considerable know-ledge of hypertension and its consequences. They reported being aware of their own BP level and whether this was within acceptable limits. They also reported being willing to take further measurements, and to consider adjusting their treatment in the light of these measurements. Other participants showed less knowledge and enthusiasm, and considered the management of hypertension to be the doctor's job. The findings suggest that for some individuals home BP measurement is acceptable. They also help to explain why, for some individuals, it is not. Using the findings, a number of changes to current practice could be made, which might make home measurements more acceptable and easier to perform. As a result, a new proforma for use in everyday practice has been designed. The study shows that there is considerable scope for sharing BP measurement and management decisions in hypertension with

  11. Blood mean platelet volume and platelet lymphocyte ratio as new predictors of hip osteoarthritis severity.

    Science.gov (United States)

    Taşoğlu, Özlem; Şahin, Ali; Karataş, Gülşah; Koyuncu, Engin; Taşoğlu, İrfan; Tecimel, Osman; Özgirgin, Neşe

    2017-02-01

    Osteoarthritis (OA) is a low grade systemic inflammatory disease in which many inflammatory mediators are known to be elevated in the peripheric blood. Blood platelet lymphocyte ratio (PLR) and mean platelet volume (MPV) are accepted as novel markers in many of the systemic inflammatory disorders, but have not been investigated in synovitis-free radiographic OA yet.The aim of this study was to evaluate the levels of blood PLR and MPV in radiographic hip OA. A total of 880 patients were evaluated retrospectively and after certain exclusion criteria, 237 of them who have primary hip OA were included. Age, sex, height, weight, body mass index, neutrophil, lymphocyte and platelet counts, erythrocyte sedimentation rate (ESR), PLR, and MPV levels were recorded, Kellgren-Lawrence (KL) grading of the hip joints were performed. Patients were then divided into 2 groups as KL grades 1 to 2 (mild-moderate) and KL grades 3 to 4 (severe) hip OA.Mean age, mean neutrophil, lymphocyte and platelet counts, mean MPV, mean PLR, and mean ESR were statistically significantly different between mild/moderate hip OA group and severe hip OA group. In univariate analysis, older age and higher MPV, PLR, and ESR were severely associated with severe hip OA. In multiple logistic regression analysis, MPV, PLR, and ESR emerged as independent predictors of severe hip OA.The results of the present study, for the first time in the literature, suggest blood PLR and MPV as novel inflammatory markers predicting the radiographic severity of hip OA in the daily practice.

  12. Liver kinetics of glucose analogs measured in pigs by PET: importance of dual-input blood sampling

    DEFF Research Database (Denmark)

    Munk, O L; Bass, L; Roelsgaard, K;

    2001-01-01

    Metabolic processes studied by PET are quantified traditionally using compartmental models, which relate the time course of the tracer concentration in tissue to that in arterial blood. For liver studies, the use of arterial input may, however, cause systematic errors to the estimated kinetic....... Hepatic arterial and portal venous blood samples and flows were measured during the scan. The dual-input function was calculated as the flow-weighted input. RESULTS: For both MG and FDG, the compartmental analysis using arterial input led to systematic underestimation of the rate constants for rapid blood...... of conventional arterial sampling underestimated these parameters compared with independent measurements of hepatic flow and hepatic blood volume. In contrast, the linear Gjedde-Patlak analysis, being less informative but more robust, gave similar parameter estimates (K, V) with both input functions...

  13. Rotating permanent magnet excitation for blood flow measurement.

    Science.gov (United States)

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

    2015-11-01

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

  14. Common Genetic Polymorphisms Influence Blood Biomarker Measurements in COPD.

    Science.gov (United States)

    Sun, Wei; Kechris, Katerina; Jacobson, Sean; Drummond, M Bradley; Hawkins, Gregory A; Yang, Jenny; Chen, Ting-Huei; Quibrera, Pedro Miguel; Anderson, Wayne; Barr, R Graham; Basta, Patricia V; Bleecker, Eugene R; Beaty, Terri; Casaburi, Richard; Castaldi, Peter; Cho, Michael H; Comellas, Alejandro; Crapo, James D; Criner, Gerard; Demeo, Dawn; Christenson, Stephanie A; Couper, David J; Curtis, Jeffrey L; Doerschuk, Claire M; Freeman, Christine M; Gouskova, Natalia A; Han, MeiLan K; Hanania, Nicola A; Hansel, Nadia N; Hersh, Craig P; Hoffman, Eric A; Kaner, Robert J; Kanner, Richard E; Kleerup, Eric C; Lutz, Sharon; Martinez, Fernando J; Meyers, Deborah A; Peters, Stephen P; Regan, Elizabeth A; Rennard, Stephen I; Scholand, Mary Beth; Silverman, Edwin K; Woodruff, Prescott G; O'Neal, Wanda K; Bowler, Russell P

    2016-08-01

    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

  15. TNO finger pressure reference guide: guide for the non-invasive finger blood pressure measurement and recording systems Portapres and Finometer

    NARCIS (Netherlands)

    2001-01-01

    With Portapres and Finometer continuous beat-to-beat finger blood pressure is measured. Although it is relatively easy to perform measurements, a basic understanding of the principles of the device is recommended to obtain reliable measurements. This reference guide addresses the volume-clamp method

  16. Context-aware patient guidance during blood pressure self-measurement

    DEFF Research Database (Denmark)

    Sandager, Puk; Lindahl, Camilla; Schlütter, Jacob Mørup

    2013-01-01

    The importance of accurate measurement of blood pressure in the screening and management of hypertension during pregnancy is well established. Blood pressure levels can be measured manually by healthcare staff or by using a blood pressure self-measurement device, either at home or in the clinic...... the blood pressure self-measurement process. Preliminary results indicate that such active and context-aware guidance leads to more reliable measurements by inhibiting non-adherent patient behavior...

  17. Precision of a new bedside method for estimation of the circulating blood volume

    DEFF Research Database (Denmark)

    Christensen, P; Eriksen, B; Henneberg, S W

    1993-01-01

    and after ventilation with a gas mixture containing 20-50 ml of CO for a period of 10-15 min. A special Water's to and fro system was designed in order to avoid any leakage when measuring during intermittent positive pressure ventilation (IPPV). Blood samples were taken before and immediately after......, determination of CBV can be performed with an amount of CO that gives rise to a harmless increase in the carboxyhemoglobin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)...

  18. 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

  19. Closed system generation of dendritic cells from a single blood volume for clinical application in immunotherapy.

    Science.gov (United States)

    Elias, M; van Zanten, J; Hospers, G A P; Setroikromo, A; de Jong, M A; de Leij, L F M H; Mulder, N H

    2005-12-01

    Dendritic cells (DC) used for clinical trials should be processed on a large scale conforming to current good manufacturing practice (cGMP) guidelines. The aim of this study was to develop a protocol for clinical grade generation of immature DC in a closed-system. Aphereses were performed with the Cobe Spectra continuous flow cell separator and material was derived from one volume of blood processed. Optimisation of a 3-phase collection autoPBSC technique significantly improved the quality of the initial mononuclear cell (MNC) product. Monocytes were then enriched from MNC by immunomagnetic depletion of CD19+ B cells and CD2+ T cells and partial depletion of NK cells using the Isolex 300I Magnetic cell selector. The quality of the initial mononuclear cell product was found to determine the outcome of monocyte enrichment. Enriched monocytes were cultured in Opticyte gas-permeable containers using CellGro serum-free medium supplemented with GM-CSF and IL-4 to generate immature DC. A seeding concentration of 1 x 10(6) was found optimal in terms of DC phenotype expression, monocyte percentage in culture, and cell viability. The differentiation pattern favours day 7 for harvest of immature DC. DC recovery, viability, as well as phenotype expression after cryopreservation of immature DC was considered in this study. DC were induced to maturation and evaluated in FACS analysis for phenotype expression and proliferation assays. Mature DC were able to generate an allogeneic T-cell response as well as an anti-CMV response as detected by proliferation assays. These data indicate that the described large-scale GMP-compatible system results in the generation of stable DC derived from one volume of blood processed, which are qualitatively and quantitatively sufficient for clinical application in immunotherapeutic protocols.

  20. Theoretical model of blood flow measurement by diffuse correlation spectroscopy

    Science.gov (United States)

    Sakadžić, Sava; Boas, David A.; Carp, Stefan

    2017-02-01

    Diffuse correlation spectroscopy (DCS) is a noninvasive method to quantify tissue perfusion from measurements of the intensity temporal autocorrelation function of diffusely scattered light. However, DCS autocorrelation function measurements in tissue better match theoretical predictions based on the diffusive motion of the scatterers than those based on a model where the advective nature of blood flow dominates the stochastic properties of the scattered light. We have recently shown using Monte Carlo (MC) simulations and assuming a simplistic vascular geometry and laminar flow profile that the diffusive nature of the DCS autocorrelation function decay is likely a result of the shear-induced diffusion of the red blood cells. Here, we provide theoretical derivations supporting and generalizing the previous MC results. Based on the theory of diffusing-wave spectroscopy, we derive an expression for the autocorrelation function along the photon path through a vessel that takes into account both diffusive and advective scatterer motion, and we provide the solution for the DCS autocorrelation function in a semi-infinite geometry. We also derive the correlation diffusion and correlation transfer equation, which can be applied for an arbitrary sample geometry. Further, we propose a method to take into account realistic vascular morphology and flow profile.

  1. Measurement of Single Cell Refractive Index, Dry Mass, Volume, and Density Using a Transillumination Microscope

    Science.gov (United States)

    Phillips, Kevin G.; Jacques, Steven L.; McCarty, Owen J. T.

    2012-09-01

    Phase contrast microscopy has become ubiquitous in the field of biology, particularly in qualitative investigations of cellular morphology. However, the use of quantitative phase retrieval methods and their connection to cellular refractive index and dry mass density remain under utilized. This is due in part to the restriction of phase and cellular mass determination to custom built instruments, involved mathematical analysis, and prohibitive sample perturbations. We introduce tomographic bright field imaging, an accessible optical imaging technique enabling the three dimensional measurement of cellular refractive index and dry mass density using a standard transillumination optical microscope. The validity of the technique is demonstrated on polystyrene spheres. The technique is then applied to the measurement of the refractive index, dry mass, volume, and density of red blood cells. This optical technique enables a simple and robust means to perform quantitative investigations of engineered and biological specimens in three dimensions using standard optical microscopes.

  2. Functional Response of Tumor Vasculature to PaCO2: Determination of Total and Microvascular Blood Volume by MRI

    Directory of Open Access Journals (Sweden)

    Scott D. Packard

    2003-07-01

    Full Text Available In order to identify differences in functional activity, we compared the reactivity of glioma vasculature and the native cerebral vasculature to both dilate and constrict in response to altered PaCO2. Gliomas were generated by unilateral implantation of U87MGdEGFR human glioma tumor cells into the striatum of adult female athymic rats. Relative changes in total and microvascular cerebral blood volume were determined by steady state contrast agent-enhanced magnetic resonance imaging for transitions from normocarbia to hypercarbia and hypocarbia. Although hypercarbia induced a significant increase in both total and microvascular blood volume in normal brain and glioma, reactivity of glioma vasculature was significantly blunted in comparison to normal striatum; glioma total CBV increased by 0.6±0.1%/mm Hg CO2 whereas normal striatum increased by 1.5±0.2%/mm Hg CO2, (P < .0001, group t-test. Reactivity of microvascular blood volume was also significantly blunted. In contrast, hypocarbia decreased both total and microvascular blood volumes more in glioma than in normal striatum. These results indicate that cerebral blood vessels derived by tumor-directed angiogenesis do retain reactivity to CO2. Furthermore, reduced reactivity of tumor vessels to a single physiological perturbation, such as hypercarbia, should not be construed as a generalized reduction of functional activity of the tumor vascular bed.

  3. Anesthesia-Induced Hypothermia Attenuates Early-Phase Blood-Brain Barrier Disruption but Not Infarct Volume following Cerebral Ischemia.

    Science.gov (United States)

    Liu, Yu-Cheng; Lee, Yu-Da; Wang, Hwai-Lee; Liao, Kate Hsiurong; Chen, Kuen-Bao; Poon, Kin-Shing; Pan, Yu-Ling; Lai, Ted Weita

    2017-01-01

    Blood-brain barrier (BBB) disruption is thought to facilitate the development of cerebral infarction after a stroke. In a typical stroke model (such as the one used in this study), the early phase of BBB disruption reaches a peak 6 h post-ischemia and largely recovers after 8-24 h, whereas the late phase of BBB disruption begins 48-58 h post-ischemia. Because cerebral infarct develops within 24 h after the onset of ischemia, and several therapeutic agents have been shown to reduce the infarct volume when administered at 6 h post-ischemia, we hypothesized that attenuating BBB disruption at its peak (6 h post-ischemia) can also decrease the infarct volume measured at 24 h. We used a mouse stroke model obtained by combining 120 min of distal middle cerebral arterial occlusion (dMCAo) with ipsilateral common carotid arterial occlusion (CCAo). This model produced the most reliable BBB disruption and cerebral infarction compared to other models characterized by a shorter duration of ischemia or obtained with dMCAO or CCAo alone. The BBB permeability was measured by quantifying Evans blue dye (EBD) extravasation, as this tracer has been shown to be more sensitive for the detection of early-phase BBB disruption compared to other intravascular tracers that are more appropriate for detecting late-phase BBB disruption. We showed that a 1 h-long treatment with isoflurane-anesthesia induced marked hypothermia and attenuated the peak of BBB disruption when administered 6 h after the onset of dMCAo/CCAo-induced ischemia. We also demonstrated that the inhibitory effect of isoflurane was hypothermia-dependent because the same treatment had no effect on ischemic BBB disruption when the mouse body temperature was maintained at 37°C. Importantly, inhibiting the peak of BBB disruption by hypothermia had no effect on the volume of brain infarct 24 h post-ischemia. In conclusion, inhibiting the peak of BBB disruption is not an effective neuroprotective strategy, especially in comparison

  4. Relationship of blood pressure variability and heart rate variability with prostatic volume in patients with benign prostatic hyperplasia

    Institute of Scientific and Technical Information of China (English)

    金江丽

    2014-01-01

    Objective To investigate the relationship of blood pressure variability(BPV)and heart rate variability(HRV)with prostatic volume(PV)in patients with benign prostatic hyperplasia(BPH).Methods A total of133 patients admitted to our department between January2011 and April 2013 were analyzed retrospectively.The patients were divided into BPH group and non-BPH group according to the PV value.The ambulatory blood

  5. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Waahlin, Anders

    2012-07-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  6. [Instrumentation for blood pressure measurements: historical aspects, concepts and sources of error].

    Science.gov (United States)

    de Araujo, T L; Arcuri, E A; Martins, E

    1998-04-01

    According to the International Council of Nurses the measurement of blood pressure is the procedure most performed by nurses in all the world. The aim of this study is to analyse the polemical aspects of instruments used in blood pressure measurement. Considering the analyses of the literature and the American Heart Association Recommendations, the main source of errors when measuring blood pressure are discussed.

  7. Combination of phlebography and sanguinous measurement of venous blood pressure

    Energy Technology Data Exchange (ETDEWEB)

    Weber, J.

    1988-07-01

    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.

  8. Simultaneous assessment of cerebral blood volume and diffusion heterogeneity using hybrid IVIM and DK MR imaging: initial experience with brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wen-Chau [National Taiwan University, Graduate Institute of Oncology, Taipei (China); National Taiwan University, Graduate Institute of Clinical Medicine, Taipei (China); National Taiwan University, Graduate Institute of Biomedical Electronics and Bioinformatics, Taipei (China); National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); Yang, Shun-Chung; Chen, Ya-Fang; My, Pei-Chi [National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); Tseng, Han-Min [National Taiwan University Hospital, Department of Neurology, Taipei (China)

    2017-01-15

    To investigate the feasibility of simultaneously assessing cerebral blood volume and diffusion heterogeneity using hybrid diffusion-kurtosis (DK) and intravoxel-incoherent-motion (IVIM) MR imaging. Fifteen healthy volunteers and 30 patients with histologically proven brain tumours (25 WHO grade II-IV gliomas and five metastases) were recruited. On a 3-T system, diffusion-weighted imaging was performed with six b-values ranging from 0 to 1,700 s/mm{sup 2}. Nonlinear least-squares fitting was employed to extract diffusion coefficient (D), diffusion kurtosis coefficient (K, a measure of the degree of non-Gaussian and heterogeneous diffusion) and intravascular volume fraction (f, a measure proportional to cerebral blood volume). Repeated-measures multivariate analysis of variance and receiver operating characteristic analysis were performed to assess the ability of D/K/f in differentiating contrast-enhanced tumour from peritumoral oedema and normal-appearing white matter. Based on our imaging setting (baseline signal-to-noise ratio = 32-128), coefficient of variation was 14-20 % for K, ∝6 % for D and 26-44 % for f. The indexes were able to differentiate contrast-enhanced tumour (Wilks' λ = 0.026, p < 10{sup -3}), and performance was greatest with K, followed by f and D. Hybrid DK IVIM imaging is capable of simultaneously measuring cerebral perfusion and diffusion indexes that together may improve brain tumour diagnosis. (orig.)

  9. Blood doping by cobalt. Should we measure cobalt in athletes?

    Directory of Open Access Journals (Sweden)

    Guidi Gian

    2006-07-01

    Full Text Available Abstract Background Blood doping is commonplace in competitive athletes who seek to enhance their aerobic performances through illicit techniques. Presentation of the hypothesis Cobalt, a naturally-occurring element with properties similar to those of iron and nickel, induces a marked and stable polycythemic response through a more efficient transcription of the erythropoietin gene. Testing the hypothesis Although little information is available so far on cobalt metabolism, reference value ranges or supplementation in athletes, there is emerging evidence that cobalt is used as a supplement and increased serum concentrations are occasionally observed in athletes. Therefore, given the athlete's connatural inclination to experiment with innovative, unfair and potentially unhealthy doping techniques, cobalt administration might soon become the most suited complement or surrogate for erythropoiesis-stimulating substances. Nevertheless, cobalt administration is not free from unsafe consequences, which involve toxic effects on heart, liver, kidney, thyroid and cancer promotion. Implications of the hypothesis Cobalt is easily purchasable, inexpensive and not currently comprehended within the World Anti-Doping Agency prohibited list. Moreover, available techniques for measuring whole blood, serum, plasma or urinary cobalt involve analytic approaches which are currently not practical for antidoping laboratories. Thus more research on cobalt metabolism in athletes is compelling, along with implementation of effective strategies to unmask this potentially deleterious doping practice

  10. Mean reticulocyte volume enhances the utility of red cell mean sphered cell volume in differentiating peripheral blood spherocytes of hereditary spherocytosis from other causes

    Directory of Open Access Journals (Sweden)

    Sukesh C Nair

    2015-01-01

    Full Text Available Context: Mean sphered cell volume (MSCV and mean reticulocyte volume (MRV are additional reticulocyte parameters generated while processing the blood samples on Beckman coulter LH 755 in the reticulocyte mode using the volume, conductivity and scatter technology. It has been observed that the difference between mean corpuscular volume (MCV and MSCV is higher in the cases of hereditary spherocytosis (HS and this difference is increasingly being utilized as a screening tool for spherocytes. In addition now there have been new observations that reticulocyte volume in cases of HS is less as compared to normal reticulocyte. Aims: Our aim was to test the usefulness of reticulocyte parameters like MSCV and MRV in distinguishing cases of HS and autoimmune hemolytic anemia (AIHA. Materials and Methods: This is a retrospective and partly prospective study where peripheral blood ethylenediaminetetraacetic acid samples from cases of HS (n = 57 and AIHA (n = 29 were processed on LH 755 in both the differential and the reticulocyte mode. The data generated were analyzed and compared with data from normal healthy donors (n = 46. Results: Using an algorithm of MCV - MSCV >10 and MRV - MSCV <25, a sensitivity of 84.2% and specificity of 94.7% was observed in cases of HS. Conclusions: With the reticulocyte analysis, we may now have a simple and cheap additional tool for screening of HS.

  11. Simultaneous evaluation of brain tumour metabolism, structure and blood volume using [18F]-fluoroethyltyrosine (FET) PET/MRI

    DEFF Research Database (Denmark)

    Henriksen, Otto M.; Larsen, Vibeke A; Muhic, Aida;

    2016-01-01

    PURPOSE: Both [(18)F]-fluoroethyltyrosine (FET) PET and blood volume (BV) MRI supplement routine T1-weighted contrast-enhanced MRI in gliomas, but whether the two modalities provide identical or complementary information is unresolved. The aims of the study were to investigate the feasibility...... congruence in the tumour volumes determined by FET PET, BV MRI and contrast-enhanced MRI. RESULTS: FET volume and TBRmax were higher in BV-positive than in BV-negative scans, and both VOLBV and rBVmax were higher in FET-positive than in FET-negative scans. TBRmax and rBVmax were positively correlated (R (2...

  12. A comprehensive Guyton model analysis of physiologic responses to preadapting the blood volume as a countermeasure to fluid shifts

    Science.gov (United States)

    Simanonok, K. E.; Srinivasan, R. S.; Myrick, E. E.; Blomkalns, A. L.; Charles, J. B.

    1994-01-01

    The Guyton model of fluid, electrolyte, and circulatory regulation is an extensive mathematical model capable of simulating a variety of experimental conditions. It has been modified for use at NASA to simulate head-down tilt, a frequently used analog of weightlessness. Weightlessness causes a headward shift of body fluids that is believed to expand central blood volume, triggering a series of physiologic responses resulting in large losses of body fluids. We used the modified Guyton model to test the hypothesis that preadaptation of the blood volume before weightless exposure could counteract the central volume expansion caused by fluid shifts, and thereby attenuate the circulatory and renal responses that result in body fluid losses. Simulation results show that circulatory preadaptation, by a procedure resembling blood donation immediately before head-down bedrest, is effective in damping the physiologic responses to fluid shifts and reducing body fluid losses. After 10 hours of head-down tilt, preadaptation also produces higher blood volume, extracellular volume, and total body water for 20 to 30 days of bedrest, compared with non-preadapted control. These results indicate that circulatory preadaptation before current Space Shuttle missions may be beneficial for the maintenance of reentry and postflight orthostatic tolerance in astronauts. This paper presents a comprehensive examination of the simulation results pertaining to changes in relevant physiologic variables produced by blood volume reduction before a prolonged head-down tilt. The objectives were to study and develop the countermeasure theoretically, to aid in planning experimental studies of the countermeasure, and to identify potentially disadvantageous physiologic responses that may be caused by the countermeasure.

  13. 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.

  14. Advanced NSCLC First Pass Perfusion at 64-slice CT: Reproducibility of Volume-based Quantitative Measurement

    Directory of Open Access Journals (Sweden)

    Jie HU

    2010-05-01

    Full Text Available Background and objective The aim of this study is to explore the reproducibility of volume-based quantitative measurement of non-small cell lung cancer (NSCLC perfusion at 64-slice CT. Methods Fourteen patients with proved advanced NSCLC were enrolled in this dynamic first pass volume-based CT perfusion (CTP study (8×5 mm collimation, and they underwent the second scan within 24 h. According to the longest diameters, those patients were classified to ≤3 cm and >3 cm groups, and each group had 7 patients. Intraclass correlation coefficient (ICC and Bland-Altman statistics were used to evaluate the reproducibility of CTP imaging. Results In both groups of advanced NSCLC, the reproducibility with BF, BV, and PS values were good (ICC >0.75 for all, but mean transit time (MTT values. For advanced NSCLC (≤3 cm, repeatability coefficient (RC values with blood flow (BF, blood volume (BV, MTT and permeability surface area product (PS values were 56%, 45%, 114%, and 78%, respectively, and the 95% change intervals of RC were -39%-53%, -29%-62%, -83%-145%, and -57%-98%, respectively. For advanced NSCLC (>3 cm, those values were 46%, 30%, 59%, and 33%, respectively, and the 95% change intervals of RC were -48%-45%, -33%-26%, -54%-64%, and -18%-48%. Conclusion There is greater reproducibility of tumor size >3 cm than that of ≤3 cm. BF and BV could be addressed for reliable clinical application in antiangiogenesis therapeutic monitoring with advanced NSCLC patients.

  15. Complete blood count using VCS (volume, conductivity, light scatter) technology is affected by hyperlipidemia in a child with acute leukemia.

    Science.gov (United States)

    Gokcebay, D G; Azik, F M; Isik, P; Bozkaya, I O; Kara, A; Tavil, E B; Yarali, N; Tunc, B

    2011-12-01

    Asparaginase, an effective drug in the treatment of childhood acute lymphoblastic leukemia (ALL), has become an important component of most childhood ALL regimens during the remission induction or intensification phases of treatment. The incidence range of asparaginase-associated lipid abnormalities that are seen in children is 67-72%. Lipemia causes erroneous results, which uses photometric methods to analyze blood samples. We describe a case of l-asparaginase-associated severe hyperlipidemia with complete blood count abnormalities. Complete blood count analysis was performed with Beckman COULTER(®) GEN·S™ system, which uses the Coulter Volume, Conductivity, Scatter technology to probe hydrodynamically focused cells. Although an expected significant inaccuracy in hemoglobin determination occurred starting from a lipid value of 3450 mg/dl, we observed that triglyceride level was 1466 mg/dl. Complete blood count analysis revealed that exceptionally high hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration levels vs. discordant with red blood cell count, mean corpuscular volume, and hematocrit levels. Total leukocyte count altered spontaneously in a wide range, and was checked with blood smear. Platelet count was in expected range (Table 1). Thus, we thought it was a laboratory error, and the patient's follow-up especially for red cell parameters was made by red blood cell and hematocrit values.

  16. Comparison of a Point-of-Care Glucometer and a Laboratory Autoanalyzer for Measurement of Blood Glucose Concentrations in Domestic Pigeons ( Columba livia domestica).

    Science.gov (United States)

    Mohsenzadeh, Mahdieh Sadat; Zaeemi, Mahdieh; Razmyar, Jamshid; Azizzadeh, Mohammad

    2015-09-01

    Biochemical analysis is necessary for diagnosis and monitoring of diseases in birds; however, the small volume of blood that can be safely obtained from small avian species often limits laboratory diagnostic testing. Consequently, a suitable methodology requiring only a small volume of blood must be used. This study was designed to compare blood glucose concentrations in domestic pigeons ( Columba livia domestica) as measured by a commercial, handheld, human glucometer and a standard autoanalyzer. During the first phase of the study, whole blood samples obtained from 30 domestic pigeons were used to measure the blood glucose concentration with a glucometer, the packed cell volume (PCV), and the total erythrocyte count (nRBC). Plasma separated from the each sample was then used to obtain the plasma glucose concentration with the autoanalyzer. During the second phase of the study, 30 pigeons were assigned to 2 equal groups (n = 15). Hypoglycemia or hyperglycemia was induced in each group by intravenous injection of insulin or glucose, respectively. Blood was collected and processed, and glucose concentrations, PCV, and nRBC were measured as previously described. Linear-regression models demonstrated a significant relationship between results measured by the glucometer and autoanalyzer results from normoglycemic (correlation coefficient [R] = 0.43, P = .02), hypoglycemic (R = 0.95; P < .001), and hyperglycemic (R = 0.81; P < .001) birds. The results of this study suggest that we can predict the real blood-glucose concentration of pigeons by using results obtained by a glucometer.

  17. The measurement and interpretation of morphine in blood.

    Science.gov (United States)

    Logan, B K; Oliver, J S; Smith, H

    1987-01-01

    A method for the determination of morphine is post-mortem blood by HPLC with electrochemical detection is described. Blood morphine levels in post-mortem cases are reported and the importance of these in causing death is discussed. These post-mortem levels are compared further with morphine levels in the blood of patients receiving morphine as an analgesic.

  18. [Interpretation and use of routine pulmonary function tests: Spirometry, static lung volumes, lung diffusion, arterial blood gas, methacholine challenge test and 6-minute walk test].

    Science.gov (United States)

    Bokov, P; Delclaux, C

    2016-02-01

    Resting pulmonary function tests (PFT) include the assessment of ventilatory capacity: spirometry (forced expiratory flows and mobilisable volumes) and static volume assessment, notably using body plethysmography. Spirometry allows the potential definition of obstructive defect, while static volume assessment allows the potential definition of restrictive defect (decrease in total lung capacity) and thoracic hyperinflation (increase in static volumes). It must be kept in mind that this evaluation is incomplete and that an assessment of ventilatory demand is often warranted, especially when facing dyspnoea: evaluation of arterial blood gas (searching for respiratory insufficiency) and measurement of the transfer coefficient of the lung, allowing with the measurement of alveolar volume to calculate the diffusing capacity of the lung for CO (DLCO: assessment of alveolar-capillary wall and capillary blood volume). All these pulmonary function tests have been the subject of an Americano-European Task force (standardisation of lung function testing) published in 2005, and translated in French in 2007. Interpretative strategies for lung function tests have been recommended, which define abnormal lung function tests using the 5th and 95th percentiles of predicted values (lower and upper limits of normal values). Thus, these recommendations need to be implemented in all pulmonary function test units. A methacholine challenge test will only be performed in the presence of an intermediate pre-test probability for asthma (diagnostic uncertainty), which is an infrequent setting. The most convenient exertional test is the 6-minute walk test that allows the assessment of walking performance, the search for arterial desaturation and the quantification of dyspnoea complaint.

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

    DEFF Research Database (Denmark)

    Henriksen, O; Ståhlberg, F; Thomsen, C;

    1989-01-01

    Quantitative measurements of blood flow based on magnetic resonance imaging (MRI) using conventional multiple spin echo sequences were evaluated in vivo in healthy young volunteers. Blood flow was measured using MRI in the femoral vein. The initial slope of the multiple spin echo decay curve...... that in vivo blood flow measurements made with MRI based on wash-out effects, commonly used in multiple spin echo imaging, do not give reliable absolute values for blood flow in the femoral artery or vein......., corrected for the T2 decay of non-flowing blood was used to calculate the blood flow. As a reference, the blood flow in the femoral artery was measured simultaneously with an invasive indicator dilution technique. T2 of non-flowing blood was measured in vivo in popliteal veins during regional circulatory...

  20. The effects of renal variation upon measurements of perfusion and leakage volume in breast tumours

    Science.gov (United States)

    Ahearn, T. S.; Staff, R. T.; Redpath, T. W.; Semple, S. I. K.

    2004-05-01

    Dynamic contrast enhanced MRI (DCE-MRI) and pharmacokinetic models have been used to measure tumour permeability (Ktrans) and leakage volume (ve) in numerous studies. The construction of pharmacokinetic models describing such tissue properties relies on defining the blood plasma concentration of contrast agent with respect to time (Cp(t)). When direct measurement is not possible a bi-exponential decay has been applied using data from healthy volunteers. This work investigates, by simulation, the magnitude of errors resulting from this definition with respect to normal variation in renal function and for cases with renal impairment. Errors up to 23% in ve and 28% in Ktrans were found for the normal simulations, and 67% in ve and 61% in Ktrans for the impaired simulations. If this bi-exponential curve is used as an input function to the generalized kinetic model and used in oncology, estimates of tissue permeability and leakage volume will possess large errors due to variation in Cp(t) curves between subjects.

  1. Comparisons of home blood glucose testing and glycated protein measurements.

    Science.gov (United States)

    Lee, P D; Sherman, L D; O'Day, M R; Rognerud, C L; Ou, C N

    1992-04-01

    We examined the relationships between 4 glycated protein assays and home blood glucose monitoring (HBGM) in 26 children with poorly-controlled insulin-dependent diabetes mellitus (IDDM) during a period of improved management. At 2 week intervals for 6 visits (12 weeks in total), HBGM records were collected and a blood sample was obtained for measurement of glycated proteins and glucose. Assays included glycated hemoglobin (GHb) and glycated serum proteins (GP) by boronate affinity chromatography, hemoglobin A1C by PolyCAT A high performance liquid chromatography (HAC) and fructosamine (FA). All 4 glycated protein levels declined significantly over the 12 week period. Significant correlations between the glycated proteins and HBGM were observed over 2 week intervals. None of the 4 assays were affected by the glucose level in the sample. Changes in mean HBGM readings over 2 week intervals were correlated with both FA and GP with wide prediction intervals. Over cumulative 2 week intervals, which may more accurately reflect longitudinal trends, all 4 glycated proteins were correlated with mean HBGM readings. At each cumulative interval, GHb and GP showed the largest variation with MBG, while FA showed the least variation with MBG. Our data indicate that of the 4 assays tested, FA has limited clinical values as compared to other glycated protein assays, whereas assays based on boronate affinity chromatography (GHb and GP) provide the most useful clinical indicators of short-term changes in glycemic control. The clinical utility of a new HPLC method for determination of glycated hemoglobins is also demonstrated.

  2. Comparison of automated oscillometric versus auscultatory blood pressure measurement.

    Science.gov (United States)

    Landgraf, Johanna; Wishner, Stanley H; Kloner, Robert A

    2010-08-01

    Most clinical offices rely on automated oscillometric devices to measure blood pressure (BP), but the accuracy of this technique versus auscultatory determination using a mercury manometer is controversial. To assess the accuracy of automated oscillometric readings, BP was measured from the same site and cuff, in 337 consecutive patients seen in a routine cardiology office, using a simultaneous connection to an automated oscillometric and a mercury manometer technique. The mean systolic BP (133 +/- 20 mm Hg) and diastolic BP (72 +/- 11 mm Hg) were significantly greater using the mercury manometer than the automated oscillometric technique (systolic 131 +/- 18 and diastolic 70 +/- 12 mm Hg, p mercury manometer) in systolic BP were seen in 22% of all patients. Discrepancies in diastolic BP were seen in 20% of all patients. The mean of the discrepancy between the 2 techniques was 1.95 +/- 5 mm Hg (range 1 to 26) for systolic BP and 1.3 +/- 4 mm Hg (range 1 to 25) for diastolic BP. The discrepancies were greater in patients >65 years. In conclusion, the mercury manometer technique resulted in consistently greater BP values than oscillometric devices. These findings have important clinical implications, including the concept that patients whose BP appears to be under control using the oscillometric technique might not be at their goal BP and might have been undertreated.

  3. Measuring the antioxidant capacity of blood plasma using potentiometry.

    Science.gov (United States)

    Tessutti, L S; Macedo, D V; Kubota, L T; Alves, A A

    2013-10-15

    The use of potentiometry to measure plasma antioxidant capacity to contribute to oxidative stress evaluation is presented. In this assay, plasma (n=60) diluted (0.3 to 1 ml) in phosphate buffer, pH 7.4, NaCl 9%, was submitted to potentiometry. A platinum wire was the working electrode and saturated calomel the reference. The results are presented as the difference between sample and buffer potential (ΔE). ΔE presented a good inverse correlation with added increasing concentrations of ascorbate (2.5-75 μmol/L; R=-0.99), urate (9.0-150 μmol/L; R=-0.99), and bilirubin (0.78-13 μmol/L; R=-0.99). Increase in the antioxidant capacity decreased ΔE. Depletion of the antioxidant capacity by tert-butylhydroperoxide (6.5-50 μmol/L) presented a direct correlation (0.97) with ΔE. Furthermore, ΔE presented an inverse correlation (R=-0.99) with increased antioxidant capacity of plasma (FRAP) induced by the addition of ascorbate (2.5-75 μmol/L). The response of the potentiometric method proved be adequate for measuring the plasma antioxidant depletion induced by acute exhaustive exercise in rats (control, n=15; exercised, n=15). This exercise decreased the concentration of urate (ppotentiometry for evaluating the antioxidant capacity of blood plasma samples.

  4. Urban Run-off Volumes Dependency on Rainfall Measurement Method

    DEFF Research Database (Denmark)

    Pedersen, L.; Jensen, N. E.; Rasmussen, Michael R.;

    2005-01-01

    Urban run-off is characterized with fast response since the large surface run-off in the catchments responds immediately to variations in the rainfall. Modeling such type of catchments is most often done with the input from very few rain gauges, but the large variation in rainfall over small area...... resolutions and single gauge rainfall was fed to a MOUSE run-off model. The flow and total volume over the event is evaluated.......Urban run-off is characterized with fast response since the large surface run-off in the catchments responds immediately to variations in the rainfall. Modeling such type of catchments is most often done with the input from very few rain gauges, but the large variation in rainfall over small areas...... suggests that rainfall needs to be measured with a much higher spatial resolution (Jensen and Pedersen, 2004). This paper evaluates the impact of using high-resolution rainfall information from weather radar compared to the conventional single gauge approach. The radar rainfall in three different...

  5. Relationship between blood group, packed cell volume, knowledge and practices of adults to malaria prevalence in Lagos Island, Nigeria

    Institute of Scientific and Technical Information of China (English)

    Bamidele Akinsanya; Adedotun Adesegun Adenusi; Oluwatobi Dolapo

    2016-01-01

    Objective:To determine malaria prevalence, knowledge, attitude and practices at residents of Lagos Island Local Government. Methods: Two hundred blood samples were collected from adults attending the General Hospital, Marina while 100 questionnaires were administered to individuals still in the same hospital. Majority of the respondents were between the ages of 18 and 30 years (44%), while the age group 60 and above had the lowest population (9%). Results:More than half of the respondents (68%) were employed and engaged in different occupations such as entrepreneur (32%), students (31%), trader (24%), and civil servant (10%). Stratification of the respondents by income revealed that 71% earned above the minimum wage, while 29% earned below. The prevalence of malaria by microscopy method was 10.5%. Malaria parasite had significant effect on the packed cell volume of infected individuals (P < 0.05). Preventive measures employed by the respondents were majorly insecticide (72.2%), while some others (5.6%) used mosquito net. Majority of the respondents (98%) believed that malaria was caused by mosquito. Conclusions: Therefore, it is appropriate to put in place preventive measures against malaria to avoid high prevalence of the number one killer in tropical Africa.

  6. HbA1c measurements from dried blood spots : validation and patient satisfaction

    NARCIS (Netherlands)

    Fokkema, Margaretha; Bakker, Andries J; de Boer, Fokje; Kooistra, Jeltsje; de Vries, Sifra; Wolthuis, Albert

    2009-01-01

    Background: This study evaluates HbA1c measurements from dried blood spots collected on filter paper and compares HbA1c from filter paper (capillary blood) with HbA1c measured in venous blood. Methods: Patient satisfaction was evaluated using a questionnaire. The performance with the filter paper me

  7. Assessment of changes in vascularity and blood volume in canine sarcomas and squamous cell carcinomas during fractionated radiation therapy using quantified contrast-enhanced power Doppler ultrasonography: a preliminary study.

    Science.gov (United States)

    Ohlerth, Stefanie; Bley, Carla Rohrer; Laluhová, Dagmar; Roos, Malgorzata; Kaser-Hotz, Barbara

    2010-10-01

    Radiation therapy does not only target tumour cells but also affects tumour vascularity. In the present study, changes in tumour vascularity and blood volume were investigated in five grade 1 oral fibrosarcomas, eight other sarcomas (non-oral soft tissue and bone sarcomas) and 12 squamous cell carcinomas in dogs during fractionated radiation therapy (total dose, 45-56 Gy). Contrast-enhanced power Doppler ultrasound was performed before fraction 1, 3, 6, 8, 10, 12, 14 and 15 or 16 (sarcomas) or 17 (squamous cell carcinomas). Prior to treatment, median vascularity and blood volume were significantly higher in squamous cell carcinomas (P=0.0005 and 0.001), whereas measurements did not differ between oral fibrosarcomas and other sarcomas (P=0.88 and 0.999). During the course of radiation therapy, only small, non-significant changes in vascularity and blood volume were observed in all three tumour histology groups (P=0.08 and P=0.213), whereas median tumour volume significantly decreased until the end of treatment (P=0.04 for fibrosarcomas and other sarcomas, P=0.008 for squamous cell carcinomas). It appeared that there was a proportional decrease in tumour volume, vascularity and blood volume. Doppler measurements did not predict progression free interval or survival in any of the three tumour groups (P=0.06-0.86). However, the number of tumours investigated was small and therefore, the results can only be considered preliminary.

  8. Challenges in blood pressure measurement in patients treated with maintenance hemodialysis.

    Science.gov (United States)

    Roberts, Matthew A; Pilmore, Helen L; Tonkin, Andrew M; Garg, Amit X; Pascoe, Elaine M; Badve, Sunil V; Cass, Alan; Ierino, Francesco L; Hawley, Carmel M

    2012-09-01

    The association between blood pressure and cardiovascular outcomes in patients undergoing hemodialysis remains controversial. This may relate in part to the technique and device used and the timing of the blood pressure measurement in relation to the hemodialysis procedure. Emerging evidence indicates that standardized hemodialysis unit blood pressure measurements or measurements obtained at home, either by the patient or using an ambulatory blood pressure monitor, may offer advantages over routine hemodialysis unit blood pressure measurements for determining cardiovascular risk and treatment. This review discusses the available evidence and implications for clinicians and clinical trials.

  9. MEASUREMENT OF REGIONAL BONE BLOOD FLOW IN THE CANINE MANDIBULAR RAMUS USING RADIOLABELLED TOAD RED BLOOD CELLS

    Institute of Scientific and Technical Information of China (English)

    毛驰; 王翰章

    1994-01-01

    Toad red blood cells were used to measure regional bone blood flow in the canine mandibular ramus.The blood cells were labelled with sodium pertechnetate and fixed in 10% formalin;they were 22×15 μm in size and had a specific gravity close to that of dog red blood cells.These cells had no discernible effect on systemic hemody-namics after injection,did not agglutinate,were well mixed and evenly distributed throughout the body,and were completely extracted in one circulation through the mandible.The mandibular ramus was divided into six regions,and the blood flow rates in each were found to be similar to those reported in previous studies with radiolabelled carbonized,microspheres.Furthermore,the blood flow distribution pattern of the mandibular ramus determined in this study was identical to that of our previous study using the bone-seeking radionuclide method.We suggest that radiolabelled toad red blood cells are an ideal marker for measuring regional blood flow in the canine mandible.

  10. Assessment of skin flaps using optically based methods for measuring blood flow and oxygenation.

    Science.gov (United States)

    Payette, Jeri R; Kohlenberg, Elicia; Leonardi, Lorenzo; Pabbies, Arone; Kerr, Paul; Liu, Kan-Zhi; Sowa, Michael G

    2005-02-01

    The objective of this study was to compare two noninvasive techniques, laser Doppler and optical spectroscopy, for monitoring hemodynamic changes in skin flaps. Animal models for assessing these changes in microvascular free flaps and pedicle flaps were investigated. A 2 x 3-cm free flap model based on the epigastric vein-artery pair and a reversed MacFarlane 3 x 10-cm pedicle flap model were used in this study. Animals were divided into four groups, with groups 1 (n = 6) and 2 (n = 4) undergoing epigastric free flap surgery and groups 3 (n = 3) and 4 (n = 10) undergoing pedicle flap surgery. Groups 1 and 4 served as controls for each of the flap models. Groups 2 and 3 served as ischemia-reperfusion models. Optical spectroscopy provides a measure of hemoglobin oxygen saturation and blood volume, and the laser Doppler method measures blood flow. Optical spectroscopy proved to be consistently more reliable in detecting problems with arterial in flow compared with laser Doppler assessments. When spectroscopy was used in an imaging configuration, oxygen saturation images of the entire flap were generated, thus creating a visual picture of global flap health. In both single-point and imaging modes the technique was sensitive to vessel manipulation, with the immediate post operative images providing an accurate prediction of eventual outcome. This series of skin flap studies suggests a potential role for optical spectroscopy and spectroscopic imaging in the clinical assessment of skin flaps.

  11. Measuring skewness of red blood cell deformability distribution by laser ektacytometry

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, S Yu; Priezzhev, A V; Lugovtsov, A E [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Ustinov, V D [M. V. Lomonosov Moscow State University, Faculty of Computational Mathematics and Cybernetics, Moscow (Russian Federation)

    2014-08-31

    An algorithm is proposed for measuring the parameters of red blood cell deformability distribution based on laser diffractometry of red blood cells in shear flow (ektacytometry). The algorithm is tested on specially prepared samples of rat blood. In these experiments we succeeded in measuring the mean deformability, deformability variance and skewness of red blood cell deformability distribution with errors of 10%, 15% and 35%, respectively. (laser biophotonics)

  12. Leg blood flow measurements using venous occlusion plethysmography during head-up tilt.

    NARCIS (Netherlands)

    Kooijman, M.; Poelkens, F.; Rongen, G.A.; Smits, P.; Hopman, M.T.E.

    2007-01-01

    We tested whether venous occlusion plethysmography (VOP) is an appropriate method to measure calf blood flow (CBF) during head-up tilt (HUT). CBF measured with VOP was compared with superficial femoral artery blood flow as measured by Doppler ultrasound during incremental tilt angles. Measurements o

  13. The Correlation between Systolic Blood Pressure Measured by Return to Flow Versus Systolic Blood Pressure Measured by Arterial Catheter in the Adult Anesthetized Patient.

    Science.gov (United States)

    1986-12-01

    a U-tube and mercury manometer for other research, he did not use it to measure arterial blood pressure (30). It was almost a century 34 N N 35 later...use of this mercury manometer decreased the size of the measuring apparatus more than 27 times (30). Carl Ludwig made an important contribution to...direct measurement of blood pressure in 1847 when he added a i graphic recording device to the mercury manometer . This eliminated observer error and

  14. Optimal blood pressure level and best measurement procedure in hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Annie Saint-Remy

    2005-10-01

    Full Text Available Annie Saint-Remy, Jean-Marie KrzesinskiNephrology-Hypertension/Dialysis Unit, University Hospital of Liège, Liège, BelgiumAbstract: Hypertension occurs frequently among hemodialysis (HD patients and can be due to many factors, such as salt intake, elevated sympathetic tone, and uremic toxins. It is responsible for the high cardiovascular risk associated with renal disease. Generally, in HD patients, while there is an elevation of systolic blood pressure (BP, diastolic BP seems to decrease, and the resultant effect is high pulse pressure, which can have a deleterious effect on the cardiovascular system. Although controversial, in the HD population the relationship between BP and risk of death seems to be U shaped, probably because of pre-existing cardiac disease in patients with the lowest BP. In chronic kidney disease, BP lower than 130/80 mmHg is recommended, but an appropriate target for BP in the HD population remains to be established. Moreover, there is no consensus regarding which routine peridialysis BP (pre- or post-dialysis BP, or both can ensure the diagnosis of hypertension in this population. Ambulatory BP monitoring remains the gold standard to quantify the integrated BP load applied to the cardiovascular system. As well, home BP assessment could contribute to improve the definition of an optimal BP in the HD population. An ideal goal for post-dialysis systolic BP seems to be a value higher than 110 mmHg and lower than 150 mmHg. However, HD patients are generally old and often have cardiac complications, so a reasonable pre-dialysis target systolic BP could be 150 mmHg. It is prudent to suggest that an improvement in BP control is necessary in the HD population, first by slow and smooth removal of extracellular volume (dry weight and thereafter by the use of appropriate antihypertensive medication.Keywords: hemodialysis, hypertension, blood pressure measurement, peridialysis blood pressure, blood pressure control

  15. Correlation between stroke volume variation and blood volume during hypovolemia%低血容量状态下患者每搏量变异度与血容量的相关性

    Institute of Scientific and Technical Information of China (English)

    李文静; 李健; 彭科

    2014-01-01

    Objective To investigate the correlation between stroke volume variation (SVV) and blood volume during hypovolemia.Methods Twenty ASA Ⅰ or Ⅱ patients,aged 20-64 years,with body mass index (BMI) of 20-30 kg/m2,scheduled for elective orthopedic operation were enrolled in this study.Anesthesia was induced with dexamethasone,midazolam,propofol,fentanyl and cisatracurium,and maintained with sevoflurane,fentanyl and cisatracurium.Then the patients received endotracheal intubation and mechanical ventilation.Heart rate (HR),mean arterial blood pressure (MAP),central venous pressure (CVP),arterial pressure-based cardiac output (APCO),SW,systemic vascular resistance (SVR) and cardiac index (Cl) were recorded 5 minutes after endotracheal intubation.Blood was taken from the central vein at a rate of 30-50 ml/min and the volume was 5% of the whole blood volume,and then haemodynamic parameters mentioned above were recorded after the haemodynamics were kept stable for 5 minutes.Blood was taken again with the method mentioned above and the haemodynamic parameters were recorded.Then 6% hydroxyethyl starch (HES) 130/0.4 was infused at 50-70 ml/min via the right internal jugular vein,and the volume was equal to 5% of the whole blood volume,and then haemodynamic parameters were recorded after the haemodynamics was kept stable for 5 minutes.Fluid replacement was performed again using the method mentioned above and the haemodynamic parameters were recorded.Linear correlation of the changes in blood volume (difference between the blood volume at each time point and the baseline value) with dSVV (difference between the value monitored at each time point and the baseline value) was analyzed.Results Significant changes were found in SW,APCO and Cl after each change in blood volume (P < 0.05 or 0.01),while no significant changes were found in HR,MAP,CVP and SVR after each change in blood volume.The change in blood volume was negatively correlated with dSVV (r =-0.875,P < 0

  16. The use of Helmholtz resonance for measuring the volume of liquids and solids.

    Science.gov (United States)

    Webster, Emile S; Davies, Clive E

    2010-01-01

    An experimental investigation was undertaken to ascertain the potential of using Helmholtz resonance for volume determination and the factors that may influence accuracy. The uses for a rapid non-interference volume measurement system range from agricultural produce and mineral sampling through to liquid fill measurements. By weighing the sample the density can also measured indirectly.

  17. The Use of Helmholtz Resonance for Measuring the Volume of Liquids and Solids

    Directory of Open Access Journals (Sweden)

    Clive E. Davies

    2010-11-01

    Full Text Available An experimental investigation was undertaken to ascertain the potential of using Helmholtz resonance for volume determination and the factors that may influence accuracy. The uses for a rapid non-interference volume measurement system range from agricultural produce and mineral sampling through to liquid fill measurements. By weighing the sample the density can also measured indirectly.

  18. Reliability of blood pressure measurement and cardiovascular risk prediction

    NARCIS (Netherlands)

    van der Hoeven, N.V.

    2016-01-01

    High blood pressure is one of the leading risk factors for cardiovascular disease, but difficult to reliably assess because there are many factors which can influence blood pressure including stress, exercise or illness. The first part of this thesis focuses on possible ways to improve the reliabili

  19. Blood flow rate measurements with indicator techniques revisited

    DEFF Research Database (Denmark)

    Sejrsen, Per; Bülow, Jens

    2009-01-01

    In view of the emerging role, disturbances in regional blood flow rate seem to play in the pathogenesis of the metabolic syndrome; we review the concepts of the classical indicator dilution and washout techniques used for determinations of regional blood flow rate. Prerequisites, assumptions...

  20. 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 tubula...

  1. Changes in plasma volume, in transcapillary escape rate of albumin and in subcutaneous blood flow during hypoglycaemia in man

    DEFF Research Database (Denmark)

    Hilsted, J; Bonde-Petersen, F; Madsbad, S;

    1985-01-01

    Hypoglycaemia was induced by insulin injected intravenously (0.15 i.u./kg body weight) in seven healthy young males. Plasma volume was measured before and during hypoglycaemia by intravenous injection of 125I before hypoglycaemia and of 131I during hypoglycaemia. Plasma volume decreased and trans...

  2. A comparison of blood pressure measurements in newborns.

    LENUS (Irish Health Repository)

    O'Shea, Joyce

    2012-02-01

    Blood pressure monitoring is an essential component of neonatal intensive care. We compared invasive and noninvasive (Dinamap, Marquette, and Dash) recordings in newborns and also noninvasive values obtained from upper and lower limbs. Infants\\' blood pressure was recorded every 6 hours for 72 hours using three noninvasive devices and compared with invasive readings taken simultaneously. Twenty-five babies were enrolled in the study, with birth weights of 560 to 4500 g and gestation 24 + 1 to 40 + 5 weeks. Three hundred thirty-two recordings were obtained. Comparison between invasive and noninvasive readings revealed that all three noninvasive monitors overread mean blood pressure. There was no significant difference between the cuff recordings obtained from the upper or lower limbs. All three noninvasive devices overestimated mean blood pressure values compared with invasive monitoring. Clinicians may be falsely reassured by noninvasive monitoring. Mean blood pressure values obtained from the upper and lower limb are similar.

  3. Effects of blood sample handling procedures on measurable inflammatory markers in plasma, serum and dried blood spot samples

    DEFF Research Database (Denmark)

    Skogstrand, K.; Thorsen, P.; Vogel, I.

    2008-01-01

    and stored for other purposes, justifies the study hereof. Blood samples were stored for 0, 4, 24, and 48 h at 4 degrees C, room temperature (RT), and at 35 degrees C, respectively, before they were separated into serum or plasma and frozen. Dried blood spot samples (DBSS) were stored for 0, 1, 2, 3, 7......The interests in monitoring inflammation by immunoassay determination of blood inflammatory markers call for information on the stability of these markers in relation to the handling of blood samples. The increasing use of stored biobank samples for such ventures that may have been collected...... increased when blood samples were stored for a period of time before the centrifugation, for certain cytokines more than 1000 fold compared to serum and plasma isolated and frozen immediately after venepuncture. The concentrations in serum generally increased more than in plasma. The measurable...

  4. Progressive reduction in central blood volume is not detected by sublingual capnography.

    Science.gov (United States)

    Chung, Kevin K; Ryan, Kathy L; Rickards, Caroline A; Hinojosa-Laborde, Carmen; Pamplin, Jeremy C; Patel, Shimul S; Herold, Thomas S; Convertino, Victor A

    2012-06-01

    Early detection and management of shock are important in optimizing clinical outcomes. One regional marker, sublingual capnography (SLCO2), is particularly appealing as redistribution of blood flow away from the sublingual mucosa can happen very early in the compensatory phase of hypovolemic shock. Our objective was to test the hypothesis that SLCO2 would detect early hypovolemia in a human laboratory model of hemorrhage: progressive lower body negative pressure until onset of cardiovascular collapse. Eighteen healthy nonsmoking subjects (10 males, 8 females) with mean age of 28 (SD, 8) years, body weight of 72 (SD, 13) kg, and height of 172 (SD, 9) cm were recruited to participate, of whom 17 completed the experiment. Average time to presyncope was 1,579 ± 72 s (mean ± SE). At the time of cardiovascular collapse, lower body negative pressure altered (P < 0.001) systolic blood pressure (mean ± SE: 130 ± 3 vs. 98 ± 2 mm Hg), pulse pressure (mean ± SE: 58 ± 2 vs. 33 ± 2 mm Hg), and heart rate (mean ± SE: 63 ± 3 vs. 102 ± 6 beats/min) when compared with baseline, whereas SLCO2 did not change (49.1 ± 1.0 vs. 48.6 ± 1.5 mm Hg, P = 0.624). In a model of progressive central hypovolemia in humans, we did not detect metabolic derangements in the sublingual mucosa as measured by SLCO2.

  5. Capillary bedside blood glucose measurement in neonates: missing a diagnosis of galactosemia.

    Science.gov (United States)

    Özbek, Mehmet Nuri; Öcal, Murat; Tanrıverdi, Sibel; Baysal, Birsen; Deniz, Ahmet; Öncel, Kahraman; Demirbilek, Hüseyin

    2015-03-01

    A number of factors may lead to inaccuracy in measurement of capillary blood glucose with a glucometer. Measurement of other carbohydrate molecules such as galactose and fructose along with glucose can potentially be a cause of error. We report a newborn patient who was referred to our hospital with conjugated bilirubinemia, hepatomegaly and high capillary blood glucose levels measured with a glucometer. Simultaneous biochemical measurements revealed normal blood glucose levels. Further investigation led to a diagnosis of classical galactosemia. Capillary blood glucose level measured with glucometer also dropped to normal values following cessation of breastfeeding and initiation of feeding with a lactose-free formula.

  6. Effect of intravenous contrast agent volume on colorectal cancer vascular parameters as measured by perfusion computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Goh, V. [Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, London (United Kingdom); Bartram, C. [Intestinal Imaging Centre, St Mark' s Hospital, Harrow, London (United Kingdom); Halligan, S. [Department of Academic Radiology, University College Hospital, London (United Kingdom)], E-mail: s.halligan@ucl.ac.uk

    2009-04-15

    Aim: To determine the effect of two different contrast agent volumes on quantitative and semi-quantitative vascular parameters as measured by perfusion computed tomography (CT) in colorectal cancer. Materials and methods: Following ethical approval and informed consent, eight prospectively recruited patients with proven colorectal adenocarcinoma underwent two separate perfusion CT studies on the same day after (a) 100 ml and (b) 50 ml of a 340 mg/ml iodinated contrast medium, respectively. Quantitative (blood volume, blood flow, permeability surface area product) and semi-quantitative (peak enhancement, time to peak enhancement) tumour vascular parameters were determined using commercial software based on distributed parameter analysis and compared using t-testing. Results: Tumour blood volume, blood flow, and permeability surface area product were not substantially different following the injection of 100 ml and 50 ml contrast medium: 6.12 versus 6.23 ml/100 g tissue; 73.4 versus 71.3 ml/min/100 g tissue; 15.6 versus 15.3 ml/min/100 g tissue for 100 and 50 ml, respectively; p > 0.05. Tumour peak enhancement and time to peak were significantly greater following the injection of 100 ml versus 50 ml contrast medium: 41.2 versus 28.5 HU; 16.1 versus 11.8 s for 100 ml and 50 ml, respectively; p = 0.002; p = 0.0003. Conclusion: Quantitative parameters do not appear to change substantially with a higher contrast agent volume suggesting a combined diagnostic staging-perfusion CT study following a single injection is feasible for colorectal cancer.

  7. Classical natural ovine scrapie prions detected in practical volumes of blood by lamb and transgenic mouse bioassays.

    Science.gov (United States)

    Dassanayake, Rohana P; Truscott, Thomas C; Zhuang, Dongyue; Schneider, David A; Madsen-Bouterse, Sally A; Young, Alan J; Stanton, James B; Davis, William C; O'Rourke, Katherine I

    2015-01-01

    Scrapie is diagnosed antemortem in sheep by detecting misfolded isoforms of prion protein (PrP(Sc)) in lymphoid follicles of the rectal mucosa and nictitating membranes. Assay sensitivity is limited if (a) the biopsy is collected early during disease development, (b) an insufficient number of follicles is collected, or (c) peripheral accumulation of PrP(Sc) is reduced or delayed. A blood test would be convenient for mass live animal scrapie testing. Currently approved techniques, however, have their own detection limits. Novel detection methods may soon offer a non-animal-based, rapid platform with detection sensitivities that rival the prion bioassay. In anticipation, we sought to determine if diseased animals could be routinely identified with a bioassay using B lymphocytes isolated from blood sample volumes commonly collected for diagnostic purposes in small ruminants. Scrapie transmission was detected in five of six recipient lambs intravenously transfused with B lymphocytes isolated from 5~10 mL of blood from a naturally scrapie-infected sheep. Additionally, scrapie transmission was observed in 18 ovinized transgenic Tg338 mice intracerebrally inoculated with B lymphocytes isolated from 5~10 mL of blood from two naturally scrapie-infected sheep. Based on our findings, we anticipate that these blood sample volumes should be of diagnostic value.

  8. Subanesthetic concentration of sevoflurane increases regional cerebral blood flow more, but regional cerebral blood volume less, than subanesthetic concentration of isoflurane in human volunteers.

    Science.gov (United States)

    Lorenz, I H; Kolbitsch, C; Hörmann, C; Schocke, M; Felber, S; Zschiegner, F; Hinteregger, M; Kremser, C; Pfeiffer, K P; Benzer, A

    2001-10-01

    Both sevoflurane and isoflurane are used in moderate concentrations in neuroanesthesia practice. The limiting factors for using higher concentrations of inhalational anesthetics in patients undergoing neurosurgery are the agents' effects on cerebral blood flow (CBF) and cerebral blood volume (CBV). In particular, an increase in CBV, which is a key determinant of intracranial pressure, may add to the neurosurgical patient's perioperative risk. To compare the effects of a subanesthetic concentration (0.4 minimum alveolar concentration) of sevoflurane or isoflurane on regional CBF (rCBF), regional CBV (rCBV) and regional mean transit time (rMTT), contrast-enhanced magnetic resonance imaging perfusion measurements were made in spontaneously breathing human volunteers. Absolute changes in rCBF, regional CBV, and rMTT during administration of either drug in regions of interest outlined bilaterally in white and grey matter were nonparametrically (Mann-Whitney test) analyzed. Sevoflurane increased rCBF in practically all regions (absolute change, 4.44 +/- 2.87 to 61.54 +/- 2.39 mL/100g per minute) more than isoflurane did (absolute change, 12.91 +/- 2.52 to 52.67 +/- 3.32 mL/100g per minute), which decreased frontal, parietal, and white matter rCBF (absolute change, -1.12 +/- 0.59 to -14.69 +/- 3.03 mL/100g per minute). Regional CBV was higher in most regions during isoflurane administration (absolute change, 0.75 +/- 0.03 to 4.92 +/- 0.16 mL/100g) than during sevoflurane administration (absolute change, 0.05 +/- 0.14 to 3.57 +/- 0.14 mL/100g). Regional mean transit time was decreased by sevoflurane (absolute change, -0.18 +/- 0.05 to -0.60 +/- 0.04 s) but increased by isoflurane (absolute change, 0.19 +/- 0.03 to 0.69 +/- 0.04 s). In summary, regional CBV was significantly lower during sevoflurane than during isoflurane administration, although sevoflurane increased rCBF more than isoflurane, which even decreased rCBF in some regions. For sevoflurane and, even more

  9. Relationship between the Integrated Intensity of the Power Spectrum of Scattered Light and Tissue Blood Volume by the Dynamic Light Scattering Method

    Science.gov (United States)

    Kashima, Susumu; Nishihara, Minoru; Takemoto, Yoshihiro; Osawa, Toshihiko

    1990-09-01

    The laser scattering characteristics from tissue microvasculature have been made clear by means of theoretical and experimental approaches. Our results show that the integrated intensity of the power spectrum correlates linearly with the volume of red blood cells in a given tissue provided the average collision number (\\bar{m}) between photons and moving red blood cells is less than unity. Also, the integrated intensity of the power spectrum is proportional to tissue blood volume if the density of red blood cells in blood (hematocrit) is constant.

  10. Ultrasonic Doppler measurement of renal artery blood flow

    Science.gov (United States)

    Freund, W. R.; Beaver, W. L.; Meindl, J. D.

    1976-01-01

    Studies were made of (1) blood flow redistribution during lower body negative pressure (LBNP), (2) the profile of blood flow across the mitral annulus of the heart (both perpendicular and parallel to the commissures), (3) testing and evaluation of a number of pulsed Doppler systems, (4) acute calibration of perivascular Doppler transducers, (5) redesign of the mitral flow transducers to improve reliability and ease of construction, and (6) a frequency offset generator designed for use in distinguishing forward and reverse components of blood flow by producing frequencies above and below the offset frequency. Finally methodology was developed and initial results were obtained from a computer analysis of time-varying Doppler spectra.

  11. Mean corpuscular volume of control red blood cells determines the interpretation of eosin-5'-maleimide (EMA) test result in infants aged less than 6 months.

    Science.gov (United States)

    Ciepiela, Olga; Adamowicz-Salach, Anna; Bystrzycka, Weronika; Łukasik, Jan; Kotuła, Iwona

    2015-08-01

    Eosin-5'-maleimide (EMA) binding test is a flow cytometric test used to detect hereditary spherocytosis (HS). To perform the test sample from patients, 5-6 reference samples of red blood are needed. Our aim was to investigate how the mean corpuscular volume (MCV) of red blood cells influences on the value of fluorescence of bounded EMA dye and how the choice of reference samples affects the test result. EMA test was performed in peripheral blood from 404 individuals, including 31 children suffering from HS. Mean fluorescence channel of EMA-RBCs was measured with Cytomics FC500 flow cytometer. Mean corpuscular volume of RBCs was assessed with LH750 Beckman Coulter. Statistical analysis was performed using Graph Pad Prism. The correlation Spearman coefficient between mean channel of fluorescence of EMA-RBCs and MCV was r = 0.39, p EMA test depends on MCV of the reference samples. If reference blood samples have lower MCV than the patients MCV, EMA test result might be negative. Due to different MCV values of RBCs in infancy and ca. Three months later, EMA test in neonates might be interpreted falsely negative. Samples from children younger than 3 months old had EMA test result 86.1 ± 11.7 %, whereas same samples that analyzed 4.1 ± 2.1 later had results of 75.4 ± 4.5 %, p EMA-bound RBC depends on RBC's volume. MCV of reference samples affects EMA test results; thus, we recommend selection of reference samples with MCV in range of ±2 fL compared to MCV of patient RBC's.

  12. Level of Mercury Manometer With Respect to Heart: Does it Affect Blood Pressure Measurement?

    Science.gov (United States)

    Kapoor, Raj; Roy, V K; Manna, S; Bhattacharjee, M

    2015-01-01

    Measurement of blood pressure is an integral part of clinical examination. Over the years various types of instruments have been used to measure blood pressure but till date the mercury sphygmomanometer is regarded as the gold standard. However, there is a myth prevalent among health professionals regarding the level of the manometer in relation to heart at the time of measuring of blood pressure. Many professionals insist that it has to be placed at the level of the heart. We argue that the limb from which pressure is measured must be at the heart level rather than the manometer. We conducted a study in which we measured the blood pressure in adults by placing the manometer at three different levels with respect to the heart. The values of blood pressure obtained at all levels were similar and did not show any statistically significant difference. We therefore conclude that the level of sphygmomanometer per se does not affect blood pressure measurement.

  13. Development of a high-sensitivity and portable cell using Helmholtz resonance for noninvasive blood glucose-level measurement based on photoacoustic spectroscopy.

    Science.gov (United States)

    Tachibana, K; Okada, K; Kobayashi, R; Ishihara, Y

    2016-08-01

    We describe the possibility of high-sensitivity noninvasive blood glucose measurement based on photoacoustic spectroscopy (PAS). The demand for noninvasive blood glucose-level measurement has increased due to the explosive increase in diabetic patients. We have developed a noninvasive blood glucose-level measurement based on PAS. The conventional method uses a straight-type resonant cell. However, the cell volume is large, which results in a low detection sensitivity and difficult portability. In this paper, a small-sized Helmholtz-type resonant cell is proposed to improve detection sensitivity and portability by reducing the cell dead volume. First, the acoustic property of the small-sized Helmholtz-type resonant cell was evaluated by performing an experiment using a silicone rubber. As a result, the detection sensitivity of the small-sized Helmholtz-type resonant cell was approximately two times larger than that of the conventional straight-type resonant cell. In addition, the inside volume was approximately 30 times smaller. Second, the detection limits of glucose concentration were estimated by performing an experiment using glucose solutions. The experimental results showed that a glucose concentration of approximately 1% was detected by the small-sized Helmholtz-type resonant cell. Although these results on the sensitivity of blood glucose-level measurement are currently insufficient, they suggest that miniaturization of a resonance cell is effective in the application of noninvasive blood glucose-level measurement.

  14. Screening blood pressure measurement in children: are we saving lives?

    Science.gov (United States)

    Brady, Tammy M; Redwine, Karen M; Flynn, Joseph T

    2014-06-01

    Blood Pressure screening in children and adolescents is currently recommended by several prominent medical organizations, including the American Heart Association, the National High Blood Pressure Education Program, the National Heart, Lung, and Blood Institute, the European Society of Hypertension, and the American Academy of Pediatrics. This practice was recently subject to intense scientific review by the U.S. Preventive Services Task Force. The conclusion of the Task Force was that "current evidence is insufficient to assess the balance of benefits and harms of screening for primary hypertension in asymptomatic children and adolescents." This commentary provides an alternate interpretation of current evidence for blood pressure screening in children and adolescents and highlights its importance as a part of routine medical care.

  15. Blood pressure measurement in hemodialysis: The importance of the measurement technique.

    Science.gov (United States)

    Kubrusly, M; de Oliveira, Claudia Maria Costa; Silva, R P; Pinheiro, M A; Rocha, M B C; Magalhães, R M

    2016-03-01

    Systemic arterial hypertension contributes to the high cardiovascular morbidity in hemodialysis (HD) patients, but the accuracy of blood pressure (BP) measurement in this population has not been well studied. To evaluate the agreement between BP measurement using the routine measurement technique (usual method) and the technique recommended by the VII Joint (standard method). This cross-sectional study enrolled 124 patients in a single center who had undergone dialysis for more than three months and were 18 years of age or older. The BP was verified at the start of dialysis by the nursing team (usual method) and by the researchers (standard method). The agreement between the systolic and diastolic BP (SBP and DBP) measurements was tested by the Bland-Altman analysis. A difference in BP measurement higher than ±5 mm Hg was considered clinically significant. The studied group had a mean age of 53.2 years. The average difference between routine and standard BP measurement was -6 mm Hg for SBP (limits of agreement: -40.1-28 mm Hg; P measured by both methods was observed in 69.4% of the patients for SBP and in 61.3% for DBP. The disagreement between the results of different BP measurement methods in HD patients was significant and the BP was underestimated using the usual BP method. BP measurement standardization should be encouraged to avoid errors in diagnosis and therapy.

  16. [Mobile Health: IEEE Standard for Wearable Cuffless Blood Pressure Measuring Devices].

    Science.gov (United States)

    Zhou, Xia; Wu, Wenli; Bao, Shudi

    2015-07-01

    IEEE Std 1708-2014 breaks through the traditional standards of cuff based blood pressure measuring devices and establishes a normative definition of wearable cuffless blood pressure measuring devices and the objective performance evaluation of this kind of devices. This study firstly introduces the background of the new standard. Then, the standard details will be described, and the impact of cuffless blood pressure measuring devices with the new standard on manufacturers and end users will be addressed.

  17. Voxel-wise relationships between distribution volume ratio and cerebral blood flow: implications for analysis of β-amyloid images

    Science.gov (United States)

    Sojkova, Jitka; Goh, Joshua; Bilgel, Murat; Landman, Bennett; Yang, Xue; Zhou, Yun; An, Yang; Beason-Held, Lori L.; Kraut, Michael A.; Wong, Dean F.; Resnick, Susan M.

    2017-01-01

    Quantification of β-amyloid (Aβ) in vivo is often accomplished using the distribution volume ratio (DVR), based on a simplified reference tissue model. We investigated the local relationships between DVR and cerebral blood flow (CBF), as well as relative blood flow (R1), in nondemented older adults. Methods Fifty-five nondemented participants (mean age 78.5 years) in the Baltimore Longitudinal Study of Aging underwent 15O-H2O PET CBF and dynamic 11C-PiB-PET. 15O-H2O PET images were normalized and smoothed using SPM. A simplified reference tissue model with linear regression and spatial constraints was used to generate parametric DVR images. The DVR images were regressed on CBF images on a voxel-by-voxel basis using robust Biological Parametric Mapping, adjusting for age and sex (FDR p=0.05, k=50). DVR images were also regressed on R1 images, a measure of the transport rate constant from vascular space to tissue. All analyses were performed in the entire sample, and in high and low tertiles of mean cortical DVR. Results Voxel-based analyses showed that increased DVR is associated with increased CBF in frontal, parietal, temporal, and occipital cortices. However, this association appears to spare regions that typically show early β-amyloid (Aβ) deposition. A more robust relationship between DVR and CBF was observed in the lowest tertile of DVR, i.e., negligible cortical Aβ load, compared to the highest tertile of cortical DVR and Aβ load. Spatial distributions of the DVR-CBF and DVR-R1 correlations showed similar patterns. No reliable negative voxel-wise relationships between DVR and CBF or R1 were observed. Conclusion Robust associations between DVR and CBF at negligible Aβ levels, together with similar spatial distributions of DVR-CBF and DVR-R1 correlations, suggest that regional distribution of DVR reflects blood flow and tracer influx rather than pattern of Aβ deposition in those with minimal Aβ load. DVR-CBF associations in individuals with higher DVR

  18. ON THE USEFULNESS OF FINGER BLOOD-PRESSURE MEASUREMENTS FOR STUDIES ON MENTAL WORKLOAD

    NARCIS (Netherlands)

    VELDMAN, JBP; RUDDEL, H; ROBBE, HWJ; Mulder, Lambertus; Mulder, Gysbertus

    1991-01-01

    Two experiments were conducted to explore the usefulness of the Penaz method for non-invasive, continuous finger blood pressure measurements during mental stress testing. In the first study, blood pressure was measured with the Penaz method, in the second it was measured intra-arterially. Two differ

  19. Red blood cell volume as a predictor of fatal reactions in cattle infected with Theileria parva Katete

    Directory of Open Access Journals (Sweden)

    P. Fandamu

    2007-09-01

    Full Text Available A comparison of mean corpuscular volume (MCV and packed cell volume (PCV was made between cattle undergoing lethal and non-lethal reactions following experimental infections with the apicomplexan protozoa, Theileria parva Katete. This work confirmed that anaemia occurs in infected animals. However, the fall in PCV was steeper in lethal reactions compared to non-lethal reactions. Our results show that animals with initially lower MCV values are more prone to fatal reaction, despite having normal PCV profiles. The study also found that small red blood cells are more likely to be infected with T. parva. These findings suggest that animals with a higher proportion of small red blood cells in circulation will be more likely to succumb to T. parva infections. The potential for using MCV as a predictor of the outcome of infection challenge is discussed.

  20. In Acute Stroke, Can CT Perfusion-Derived Cerebral Blood Volume Maps Substitute for Diffusion-Weighted Imaging in Identifying the Ischemic Core?

    Directory of Open Access Journals (Sweden)

    William A Copen

    Full Text Available In the treatment of patients with suspected acute ischemic stroke, increasing evidence suggests the importance of measuring the volume of the irreversibly injured "ischemic core." The gold standard method for doing this in the clinical setting is diffusion-weighted magnetic resonance imaging (DWI, but many authors suggest that maps of regional cerebral blood volume (CBV derived from computed tomography perfusion imaging (CTP can substitute for DWI. We sought to determine whether DWI and CTP-derived CBV maps are equivalent in measuring core volume.58 patients with suspected stroke underwent CTP and DWI within 6 hours of symptom onset. We measured low-CBV lesion volumes using three methods: "objective absolute," i.e. the volume of tissue with CBV below each of six published absolute thresholds (0.9-2.5 mL/100 g, "objective relative," whose six thresholds (51%-60% were fractions of mean contralateral CBV, and "subjective," in which two radiologists (R1, R2 outlined lesions subjectively. We assessed the sensitivity and specificity of each method, threshold, and radiologist in detecting infarction, and the degree to which each over- or underestimated the DWI core volume. Additionally, in the subset of 32 patients for whom follow-up CT or MRI was available, we measured the proportion of CBV- or DWI-defined core lesions that exceeded the follow-up infarct volume, and the maximum amount by which this occurred.DWI was positive in 72% (42/58 of patients. CBV maps' sensitivity/specificity in identifying DWI-positive patients were 100%/0% for both objective methods with all thresholds, 43%/94% for R1, and 83%/44% for R2. Mean core overestimation was 156-699 mL for objective absolute thresholds, and 127-200 mL for objective relative thresholds. For R1 and R2, respectively, mean±SD subjective overestimation were -11±26 mL and -11±23 mL, but subjective volumes differed from DWI volumes by up to 117 and 124 mL in individual patients. Inter-rater agreement

  1. Dual energy CT pulmonary blood volume assessment in acute pulmonary embolism - correlation with D-dimer level, right heart strain and clinical outcome

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Ralf W.; Frellesen, Claudia; Schell, Boris; Lehnert, Thomas; Jacobi, Volkmar; Vogl, Thomas J.; Kerl, J.M. [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Renker, Matthias [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Medical University of South Carolina, Heart and Vascular Center, Ashley River Tower, Charleston, SC (United States); Ackermann, Hanns [Clinic of the Goethe University, Department of Biostatistics and Mathematical Modelling, Frankfurt (Germany); Schoepf, U.J. [Medical University of South Carolina, Heart and Vascular Center, Ashley River Tower, Charleston, SC (United States)

    2011-09-15

    To investigate the role of perfusion defect (PD) size on dual energy CT pulmonary blood volume assessment as predictor of right heart strain and patient outcome and its correlation with d-dimer levels in acute pulmonary embolism (PE). 53 patients with acute PE who underwent DECT pulmonary angiography were retrospectively analyzed. Pulmonary PD size caused by PE was measured on DE iodine maps and quantified absolutely (VolPD) and relatively to the total lung volume (RelPD). Signs of right heart strain (RHS) on CT were determined. Information on d-dimer levels and readmission for recurrent onset of PE and death was collected. D-dimer level was mildly (r = 0.43-0.47) correlated with PD size. Patients with RHS had significantly higher VolPD (215 vs. 73 ml) and RelPD (9.9 vs. 2.9%) than patients without RHS (p < 0.003). There were 2 deaths and 1 readmission due of PE in 18 patients with >5% RelPD, while no such events were found for patients with <5% RelPD. Pulmonary blood volume on DECT in acute PE correlates with RHS and appears to be a predictor of patient outcome in this pilot study. (orig.)

  2. Iodine status and its correlations with age, blood pressure, and thyroid volume in South Indian women above 35 years of age (Amrita Thyroid Survey

    Directory of Open Access Journals (Sweden)

    Vadayath Usha Menon

    2011-01-01

    Full Text Available Background: Thyroid disorders are more commonly seen among females and the prevalence increases with age. There is no population data from India focusing on iodine levels and their correlations with thyroid volume and other factors in adult women. Aim: This study was designed to establish the iodine status and its relation with various factors including thyroid volume measured by ultrasound among the females of Kerala. Materials and Methods: This was a cross sectional house to house survey among the females above 35 years of age in a randomly selected urban area in Cochin Corporation, Kerala State, India. Selected subjects were interviewed, examined and blood and urine tests were done. Thyroid volume was calculated using ultrasound. Results: Among the 508 subjects who participated in the checkup, 471 subjects were included for analysis. Mean age was 50.3 + 10.7 years and 53.2% were postmenopausal. A total of 98% of the subjects were using iodized salt and median urinary iodine excretion (UIE was 162.6 mcg/l. UIE had negative correlation with age and systolic blood pressure (BP, but had no correlation with thyroid volume (TV, thyroid nodularity, free thyroxine 4 (FT4, thyroid stimulating hormone (TSH or anti thyroid peroxidase (TPO levels. Iodine deficiency was more commonly seen in subjects with hypertension and also among postmenopausal females. Conclusions: This study showed that females > 35 years were iodine sufficient, though one third of the subjects had UIE levels less than the recommended level. Iodine levels had significant negative correlation with age and systolic BP and no correlation with thyroid volume or biochemical parameters. Iodine deficiency was significantly higher in subjects with new and known hypertension and this relation merits further evaluation.

  3. Volumes of chronic traumatic frontal brain lesions measured by MR imaging and CBF tomography

    Energy Technology Data Exchange (ETDEWEB)

    Maeder, P.; Wirsen, A.; Bajc, M.; Schalen, W.; Sjoeholm, H.; Skeidsvoll, H.; Cronqvist, S.; Ingvar, D.H. (University Hospital, Lund (Sweden). Dept. of Neuroradiology University Hospital, Lund (Sweden). Dept. of Clinical Neurophysiology University Hospital, Lund (Sweden). Dept. of Neurosurgery)

    1991-07-01

    The volumes (ml) of chronic traumatic frontal brain lesions were compared measured 'morphologically' with MR imaging (T1 and T2 weighted images) and 'functionally' with a tomographic rCBF technique (SPECT with {sup 133}Xe i.v.). The T1 volumes varied between 11 and 220 ml. The correlation between T1 and T2 volumes was 0.95, the T2 volumes being 33% larger than T1 volumes (p<0.001). The functional SPECT volumes were considerably larger (range 16-324 ml) than the MR volumes. The mean volume difference was 81% between T1 and SPECT images (p<0.001), and 35% between T2 and SPECT images (p<0.001). Correlations between the MR and SPECT volumes were also higher for T2 than T1 volumes. The volume difference is most likely explained by a functional decrease in regions around the lesion in which no morphologic change visible on MR images had taken place. MR and SPECT volume measurements were positively related to persistent lack of energy and personality changes, but only moderately related to duration of impaired consciousness and neuropsychologie outcome. (orig.).

  4. Evaluation of left ventricular volumes measured by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Møgelvang, J; Thomsen, C; Mehlsen, J;

    1986-01-01

    Left ventricular end-diastolic and end-systolic volumes were determined in 17 patients with different levels of left ventricular function by magnetic resonance imaging (MRI). A 1.5 Tesla Magnet was used obtaining ECG triggered single and multiple slices. Calculated cardiac outputs were compared...

  5. Evaluation of right ventricular volumes measured by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Møgelvang, J; Stubgaard, M; Thomsen, C;

    1988-01-01

    Right ventricular volumes were determined in 12 patients with different levels of right and left ventricular function by magnetic resonance imaging (MRI) using an ECG gated multisection technique in planes perpendicular to the diastolic position of the interventricular septum. Right ventricular...

  6. Spatial Visualization Tasks to Support Students' Spatial Structuring in Learning Volume Measurement

    Science.gov (United States)

    Revina, Shintia; Zulkardi; Darmawijoyo; van Galen, Frans

    2011-01-01

    Many prior researches found that most of students in grade five tended to have difficulty in fully grasping the concept of volume measurement because they have to build their competence in spatial structuring. The unit of volume "packing" measurement must be integrated and coordinated in three-dimension. On the other hand, it is revealed…

  7. Archimedes Revisited: A Faster, Better, Cheaper Method of Accurately Measuring the Volume of Small Objects

    Science.gov (United States)

    Hughes, Stephen W.

    2005-01-01

    A little-known method of measuring the volume of small objects based on Archimedes' principle is described, which involves suspending an object in a water-filled container placed on electronic scales. The suspension technique is a variation on the hydrostatic weighing technique used for measuring volume. The suspension method was compared with two…

  8. The Effect of a Finite Measurement Volume on Power Spectra from a Burst Type LDA

    DEFF Research Database (Denmark)

    Buchhave, Preben; Velte, Clara Marika; K. George, William

    2014-01-01

    We analyze the effects of a finite size measurement volume on the power spectrum computed fromdata acquired with a burst-type laser Doppler anemometer. The finite measurement volume causes temporal distortions in acquisition of the data resulting in phenomena such as finite processing time and de...

  9. Blood

    Science.gov (United States)

    ... Also, blood is either Rh-positive or Rh-negative. So if you have type A blood, it's either A positive or A negative. Which type you are is important if you need a blood transfusion. And your Rh factor could be important ...

  10. Comparison of medical of volume measurement of the prostate by transrectal ultrasound: Experiment with jelly models

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jeong Yeon; Lee, Hak Jong; Kim, Sung Hyun [Samsung Seoul Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Seung Hyup [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2002-03-15

    To evaluate the accuracy of measuring the volume of the prostate using the prolate ellipsoid volume calculation method (antero-posterior (AP) diameter X length X width X {pi}6) when the antero-posterior diameter of the prostate was measured on midsagittal (sagittal volume) and axial plane (axial volume).The devil's tongue jelly was used for the creation of ultrasound model of the prostate (volume: 15-40 cc) by cutting and shaping the surface. The volume in 10 prostatic models and 30 patients was measured and calculated. First, the AP diameter and length of the prostate models in midsagittal plane, and the height and width of the models in axial plane were measured for 3 times. The volume was calculated in two ways, one using the AP diameter an midsagittal plane and the other using the AP diameter in axial plane. The true volume of the model was measured using mess cylinder. The calculated volume and true volume were compared, and the accuracy of two method of measuring the prostatic volume was evaluated by Friedman test. The intraobserver variation was evaluated by General Linear Model, Repeated Measure. The reproducibility was evaluated by Cronbach's {alpha}. In vivo study was also performed in 30 patients. The prostate volume was calculated in the same manner. These volume data were analyzed by statistical method, and the intraobeserver variation was evaluated. While there was a statistically significant difference between the sagittal and true volume of the models, there was no statistical significant difference between the axial and true volumes. There was no significant intraobserver variation between both methods. The reproducibility was high in both methods with Cronbach's {alpha} of 0.977 and 0.942. The sagittal volume was larger than the axial volume in 30 patients with a statistically significant difference. There was no significant intraobserver variation in both methods. The reproducibility was high in both methods Cronbach's {alpha

  11. Reduced blood pressure of CFTR-F508del carriers correlates with diminished arterial reactivity rather than circulating blood volume in mice.

    Directory of Open Access Journals (Sweden)

    Veronica A Peotta

    Full Text Available The F508del mutation of the cystic fibrosis transmembrane conductance regulator (CFTR is the most common cause of cystic fibrosis (CF. Both CF patients and F508del carriers have decreased blood pressure. While this has been attributed to salt depletion, recent studies have shown F508del expression interferes with smooth muscle cell calcium mobilization. We tested the hypothesis that carriers of the F508del mutation have lower adult blood pressures and reduced aortic contractility without a reduction in circulating blood volume. By radiotelemetry, F508del heterozygous mice had significantly lower arterial pressures than wild-type C57BL/6 controls, with the greatest effect seen at the time of dark-to-light cycle transition (mean difference of 10 mmHg. To replicate the vascular effects of sympathetic arousal, isoproterenol and epinephrine were co-infused, and F508del mice again had significantly reduced arterial pressures. Aortas isolated from F508del heterozygous mice had significantly decreased constriction to noradrenaline (0.9 ± 0.2 versus 2.9 ± 0.7 mN. Inhibition of wild-type CFTR or the inositol triphosphate receptor replicated the phenotype of F508del aortas. CFTR carrier status did not alter circulating blood volume. We conclude the CFTR-F508del mutation decreases aortic contractility and lowers arterial pressures. As a cAMP-activated chloride channel that facilitates calcium mobilization, we speculate wild-type CFTR co-activation during adrenergic receptor stimulation buffers the vasodilatory response to catecholamines, and loss of this compensatory vasoconstrictor tone may contribute to the lower arterial pressures seen in heterozygote carriers of a CFTR-F508del mutation.

  12. Adaptive control with self-tuning for non-invasive beat-by-beat blood pressure measurement.

    Science.gov (United States)

    Nogawa, Masamichi; Ogawa, Mitsuhiro; Yamakoshi, Takehiro; Tanaka, Shinobu; Yamakoshi, Ken-ichi

    2011-01-01

    Up to now, we have successfully carried out the non-invasive beat-by-beat measurement of blood pressure (BP) in the root of finger, superficial temporal and radial artery based on the volume-compensation technique with reasonable accuracy. The present study concerns with improvement of control method for this beat-by-beat BP measurement. The measurement system mainly consists of a partial pressurization cuff with a pair of LED and photo-diode for the detection of arterial blood volume, and a digital self-tuning control method. Using healthy subjects, the performance and accuracy of this system were evaluated through comparison experiments with the system using a conventional empirically tuned PID controller. The significant differences of BP measured in finger artery were not showed in systolic (SBP), p=0.52, and diastolic BP (DBP), p=0.35. With the advantage of the adaptive control with self-tuning method, which can tune the control parameters without disturbing the control system, the application area of the non-invasive beat-by-beat measurement method will be broadened.

  13. Measurement of breast volume is a useful supplement to select candidates for surgical breast reduction

    DEFF Research Database (Denmark)

    Ikander, Peder; Drejøe, Jennifer Berg; Lumholt, Pavia

    2014-01-01

    , the indication seemed to be less clear-cut, and additional parameters need to be included. CONCLUSION: Breast volume can be used as an objective criterion in addition to the presently used criteria. Breast volume can easily be measured and has become appreciated by plastic surgeons dealing with patients...... in the period from January 2007 to March 2011 were included prospectively in the study. The patients' subjective complaints, height, weight and standard breast measurements were registered as well as the decision for or against surgery. Breast volume was measured using transparent plastic cups. RESULTS: Cut......-off values for breast volume were calculated based on whether or not the patients were offered reduction surgery. Most patients (93%) with a breast volume below 800 cc were not offered surgery, while most with a volume exceeding 900 cc were offered surgery (94%). In the grey zone between 800 and 900 cc...

  14. Deformability measurement of red blood cells using a microfluidic channel array and an air cavity in a driving syringe with high throughput and precise detection of subpopulations.

    Science.gov (United States)

    Kang, Yang Jun; Ha, Young-Ran; Lee, Sang-Joon

    2016-01-07

    Red blood cell (RBC) deformability has been considered a potential biomarker for monitoring pathological disorders. High throughput and detection of subpopulations in RBCs are essential in the measurement of RBC deformability. In this paper, we propose a new method to measure RBC deformability by evaluating temporal variations in the average velocity of blood flow and image intensity of successively clogged RBCs in the microfluidic channel array for specific time durations. In addition, to effectively detect differences in subpopulations of RBCs, an air compliance effect is employed by adding an air cavity into a disposable syringe. The syringe was equally filled with a blood sample (V(blood) = 0.3 mL, hematocrit = 50%) and air (V(air) = 0.3 mL). Owing to the air compliance effect, blood flow in the microfluidic device behaved transiently depending on the fluidic resistance in the microfluidic device. Based on the transient behaviors of blood flows, the deformability of RBCs is quantified by evaluating three representative parameters, namely, minimum value of the average velocity of blood flow, clogging index, and delivered blood volume. The proposed method was applied to measure the deformability of blood samples consisting of homogeneous RBCs fixed with four different concentrations of glutaraldehyde solution (0%-0.23%). The proposed method was also employed to evaluate the deformability of blood samples partially mixed with normal RBCs and hardened RBCs. Thereafter, the deformability of RBCs infected by human malaria parasite Plasmodium falciparum was measured. As a result, the three parameters significantly varied, depending on the degree of deformability. In addition, the deformability measurement of blood samples was successfully completed in a short time (∼10 min). Therefore, the proposed method has significant potential in deformability measurement of blood samples containing hematological diseases with high throughput and precise detection of

  15. Ultrasonic Measurement of Fluid Viscosity for Blood Characterization

    Science.gov (United States)

    Nitta, Naotaka; Homma, Kazuhiro

    2005-06-01

    Although plaque rupture in arteriosclerosis is affected by not only its strength but also by hemodynamic factors, such as blood pressure and shear stress, in particular, the viscous coefficient which directly controls the magnitude of shear stress might be a risk factor in plaque rupture. Therefore, if the viscous coefficient can be assessed noninvasively, it can be a useful index for prediction of a plaque rupture and assessment of various diseases. In this work, an ultrasonic methodology to estimate the viscous coefficient was investigated by numerical simulation and flow-phantom experiment as the fundamental investigation for noninvasively assessing the viscous characteristics of blood. These results show that the proposed method is useful for estimating the kinematic viscosity coefficient in the viscous evaluation of blood.

  16. Pile volume measurement by range imaging camera in indoor environment

    OpenAIRE

    C. Altuntas

    2014-01-01

    Range imaging (RIM) camera is recent technology in 3D location measurement. The new study areas have been emerged in measurement and data processing together with RIM camera. It has low-cost and fast measurement technique compared to the current measurement techniques. However its measurement accuracy varies according to effects resulting from the device and the environment. The direct sunlight is affect measurement accuracy of the camera. Thus, RIM camera should be used for indoor ...

  17. Advanced Recording and Preprocessing of Physiological Signals. [data processing equipment for flow measurement of blood flow by ultrasonics

    Science.gov (United States)

    Bentley, P. B.

    1975-01-01

    The measurement of the volume flow-rate of blood in an artery or vein requires both an estimate of the flow velocity and its spatial distribution and the corresponding cross-sectional area. Transcutaneous measurements of these parameters can be performed using ultrasonic techniques that are analogous to the measurement of moving objects by use of a radar. Modern digital data recording and preprocessing methods were applied to the measurement of blood-flow velocity by means of the CW Doppler ultrasonic technique. Only the average flow velocity was measured and no distribution or size information was obtained. Evaluations of current flowmeter design and performance, ultrasonic transducer fabrication methods, and other related items are given. The main thrust was the development of effective data-handling and processing methods by application of modern digital techniques. The evaluation resulted in useful improvements in both the flowmeter instrumentation and the ultrasonic transducers. Effective digital processing algorithms that provided enhanced blood-flow measurement accuracy and sensitivity were developed. Block diagrams illustrative of the equipment setup are included.

  18. Two-dimensional ultrasound measurement of thyroid gland volume: a new equation with higher correlation with 3-D ultrasound measurement.

    Science.gov (United States)

    Ying, Michael; Yung, Dennis M C; Ho, Karen K L

    2008-01-01

    This study aimed to develop a new two-dimensional (2-D) ultrasound thyroid volume estimation equation using three-dimensional (3-D) ultrasound as the standard of reference, and to compare the thyroid volume estimation accuracy of the new equation with three previously reported equations. 2-D and 3-D ultrasound examinations of the thyroid gland were performed in 150 subjects with normal serum thyrotropin (TSH, thyroid-stimulating hormone) and free thyroxine (fT4) levels (63 men and 87 women, age range: 17 to 71 y). In each subject, the volume of both thyroid lobes was measured by 3-D ultrasound. On 2-D ultrasound, the craniocaudal (CC), lateromedial (LM) and anteroposterior (AP) dimensions of the thyroid lobes were measured. The equation was derived by correlating the volume of the thyroid lobes measured with 3-D ultrasound and the product of the three dimensions measured with 2-D ultrasound using linear regression analysis, in 75 subjects without thyroid nodule. The accuracy of thyroid volume estimation of the new equation and the three previously reported equations was evaluated and compared in another 75 subjects (without thyroid nodule, n = 30; with thyroid nodule, n = 45). It is suggested that volume of thyroid lobe may be estimated as: volume of thyroid lobe = 0.38.(CC.LM.AP) + 1.76. Result showed that the new equation (16.9% to 36.1%) had a significantly smaller thyroid volume estimation error than the previously reported equations (20.8% to 54.9%) (p thyroid volume estimation error when thyroid glands with nodules were examined (p thyroid volume equation, 2-D ultrasound can be a useful alternative in thyroid volume measurement when 3-D ultrasound is not available.

  19. Tomographic cerebral blood flow measurement during carotid surgery

    DEFF Research Database (Denmark)

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

    1994-01-01

    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...... RESULTS: We found a significant correlation between stump pressure and enhancement of side-to-side asymmetry in rCBF due to carotid cross clamping. Pronounced variations were seen in which regions were deprived of perfusion during clamping. CONCLUSION: TcHMPAO allows tomographic assessment of CBF during...

  20. New algorithm and system for measuring size distribution of blood cells

    Institute of Scientific and Technical Information of China (English)

    Cuiping Yao(姚翠萍); Zheng Li(李政); Zhenxi Zhang(张镇西)

    2004-01-01

    In optical scattering particle sizing, a numerical transform is sought so that a particle size distribution can be determined from angular measurements of near forward scattering, which has been adopted in the measurement of blood cells. In this paper a new method of counting and classification of blood cell, laser light scattering method from stationary suspensions, is presented. The genetic algorithm combined with nonnegative least squared algorithm is employed to inverse the size distribution of blood cells. Numerical tests show that these techniques can be successfully applied to measuring size distribution of blood cell with high stability.

  1. Blood pressure monitor with a position sensor for wrist placement to eliminate hydrostatic pressure effect on blood pressure measurement.

    Science.gov (United States)

    Sato, Hironori; Koshimizu, Hiroshi; Yamashita, Shingo; Ogura, Toshihiko

    2013-01-01

    Accurate measurement of blood pressure at wrist requires the heart and wrist to be kept at the same level to avoid the effects of hydrostatic pressure. Although a blood pressure monitor with a position sensor that guides appropriate forearm angle without use of a chair and desk has already been proposed, a similar functioning device for measuring upper arm blood pressure with a chair and desk is needed. In this study, a calculation model was first used to explore design of such a system. The findings were then implemented into design of a new blood pressure monitor. Results of various methods were compared. The calculation model of the wrist level from arthrosis angles and interarticulars lengths was developed and considered using published anthropometric dimensions. It is compared with 33 volunteer persons' experimental results. The calculated difference of level was -4.1 to 7.9 (cm) with a fixed chair and desk. The experimental result was -3.0 to 5.5 (cm) at left wrist and -2.1 to 6.3(cm) at right wrist. The absolute difference level equals ±4.8 (mmHg) of blood pressure readings according to the calculated result. This meets the AAMI requirements for a blood pressure monitor. In the conclusion, the calculation model is able to effectively evaluate the difference between the heart and wrist level. Improving the method for maintaining wrist to heart level will improve wrist blood pressure measurement accuracy when also sitting in the chair at a desk. The leading angle of user's forearm using a position sensor is shown to work for this purpose.

  2. The Effect of Radioactive Lantern Mantle Powder and Bentonite-Zeoloite Minerals on the Volume of Blood Loss, Bleeding and Clotting Time

    Directory of Open Access Journals (Sweden)

    M Atefi

    2009-04-01

    Full Text Available ABSTRACT Introduction & Objective: Over the past decade the US army has widely studied new technologies for stopping sever hemorrhages and has introduced an effective Zeolite based hemostatic agent. On the other hand, Mortazavi and his colleagues previously reported the bio-stimulatory effects of the topical application of radioactive lantern mantle powder on wound healing. Their subsequent studies showed significant changes in some histological parameters concerning healing. In this light, here the bio-stimulatory effect of burned radioactive lantern mantles powder as well as two minerals bentonite and zeolite are presented. Materials & Methods: This experimental study was conducted in the center for radiological studies, Shiraz University of Medical Sciences in 2008. Fifty male Wistar rats were divided randomly into 5 groups of 10 animals each. Following anesthesia, animals’ tails were cut at a thickness of 5 mm by using a surgical scissor. No intervention was made on the animals of the 1st group. The 2nd to 4th group received topical non-radioactive lantern mantle powder, radioactive lantern mantle powder, Bentonite mineral or a mixture of Bentonite-Zeoliteat minerals respectively. After treatment with above mentioned agents, the volume of blood loss was measured using a scaled test-tube. The bleeding time and clotting time were also measured using a chronometer. SPSS software was used for statistical analysis. ANOVA was used for comparing the means of each parameter in the 5 groups. Results: The the volume of blood loss, bleeding and clotting times in control animals were 4.39±1.92 cc, 112.10±39.60 sec and 94.9±54.26 sec, respectively. In the 5th group in which the animals were treated with a mixture of Bentonite-Zeoliteat minerals, the volume of blood loss, bleeding and clotting times were 1.31±0.60 cc, 34.50±4.65 sec and 24.2±4.61 sec, respectively. Conclusion: This is the 1st investigation that studied the alterations of bleeding

  3. Adrenal gland volume measurement in septic shock and control patients: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Nougaret, Stephanie; Aufort, S.; Gallix, B. [Hopital Saint Eloi, Department of Abdominal Imaging, CHU Montpellier, Montpellier, Cedex 5 (France); Jung, B.; Chanques, G.; Jaber, S. [Hopital Saint Eloi, Intensive Care Unit, Department of Critical Care and Anesthesiology: DAR B, CHU Montpellier, Montpellier, Cedex 5 (France)

    2010-10-15

    To compare adrenal gland volume in septic shock patients and control patients by using semi-automated volumetry. Adrenal gland volume and its inter-observer variability were measured with tomodensitometry using semi-automated software in 104 septic shock patients and in 40 control patients. The volumes of control and septic shock patients were compared and the relationship between volume and outcome in intensive care was studied. The mean total volume of both adrenal glands was 7.2 {+-} 2.0 cm{sup 3} in control subjects and 13.3 {+-} 4.7 cm{sup 3} for total adrenal gland volume in septic shock patients (p < 0.0001). Measurement reproducibility was excellent with a concordance correlation coefficient value of 0.87. The increasing adrenal gland volume was associated with a higher rate of survival in intensive care. The present study reports that with semi-automated software, adrenal gland volume can be measured easily and reproducibly. Adrenal gland volume was found to be nearly double in sepsis compared with control patients. The absence of increased volume during sepsis would appear to be associated with a higher rate of mortality and may represent a prognosis factor which may help the clinician to guide their strategy. (orig.)

  4. Measurement of interaction forces between red blood cells in aggregates by optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Maklygin, A Yu; Priezzhev, A V; Karmenian, A; Nikitin, Sergei Yu; Obolenskii, I S; Lugovtsov, Andrei E; Kisun Li

    2012-06-30

    We have fabricated double-beam optical tweezers and demonstrated the possibility of their use for measuring the interaction forces between red blood cells (erythrocytes). It has been established experimentally that prolonged trapping of red blood cells in a tightly focused laser beam does not cause any visible changes in their shape or size. We have measured the interaction between red blood cells in the aggregate, deformed by optical tweezers.

  5. Measures of blood pressure and cognition in dialysis patients

    Science.gov (United States)

    There are few reports on the relationship of blood pressure with cognitive function in maintenance dialysis patients. The Cognition and Dialysis Study is an ongoing investigation of cognitive function and its risk factors in six Boston area hemodialysis units. In this analysis, we evaluated the rela...

  6. 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...

  7. Semiautomatic regional segmentation to measure orbital fat volumes in thyroid-associated ophthalmopathy. A validation study.

    Science.gov (United States)

    Comerci, M; Elefante, A; Strianese, D; Senese, R; Bonavolontà, P; Alfano, B; Bonavolontà, B; Brunetti, A

    2013-08-01

    This study was designed to validate a novel semi-automated segmentation method to measure regional intra-orbital fat tissue volume in Graves' ophthalmopathy. Twenty-four orbits from 12 patients with Graves' ophthalmopathy, 24 orbits from 12 controls, ten orbits from five MRI study simulations and two orbits from a digital model were used. Following manual region of interest definition of the orbital volumes performed by two operators with different levels of expertise, an automated procedure calculated intra-orbital fat tissue volumes (global and regional, with automated definition of four quadrants). In patients with Graves' disease, clinical activity score and degree of exophthalmos were measured and correlated with intra-orbital fat volumes. Operator performance was evaluated and statistical analysis of the measurements was performed. Accurate intra-orbital fat volume measurements were obtained with coefficients of variation below 5%. The mean operator difference in total fat volume measurements was 0.56%. Patients had significantly higher intra-orbital fat volumes than controls (p<0.001 using Student's t test). Fat volumes and clinical score were significantly correlated (p<0.001). The semi-automated method described here can provide accurate, reproducible intra-orbital fat measurements with low inter-operator variation and good correlation with clinical data.

  8. Measurement of transplanted pancreatic volume using computed tomography: reliability by intra- and inter-observer variability

    Energy Technology Data Exchange (ETDEWEB)

    Lundqvist, Eva; Segelsjoe, Monica; Magnusson, Anders [Uppsala Univ., Dept. of Radiology, Oncology and Radiation Science, Section of Radiology, Uppsala (Sweden)], E-mail: eva.lundqvist.8954@student.uu.se; Andersson, Anna; Biglarnia, Ali-Reza [Dept. of Surgical Sciences, Section of Transplantation Surgery, Uppsala Univ. Hospital, Uppsala (Sweden)

    2012-11-15

    Background Unlike other solid organ transplants, pancreas allografts can undergo a substantial decrease in baseline volume after transplantation. This phenomenon has not been well characterized, as there are insufficient data on reliable and reproducible volume assessments. We hypothesized that characterization of pancreatic volume by means of computed tomography (CT) could be a useful method for clinical follow-up in pancreas transplant patients. Purpose To evaluate the feasibility and reliability of pancreatic volume assessment using CT scan in transplanted patients. Material and Methods CT examinations were performed on 21 consecutive patients undergoing pancreas transplantation. Volume measurements were carried out by two observers tracing the pancreatic contours in all slices. The observers performed the measurements twice for each patient. Differences in volume measurement were used to evaluate intra- and inter-observer variability. Results The intra-observer variability for the pancreatic volume measurements of Observers 1 and 2 was found to be in almost perfect agreement, with an intraclass correlation coefficient (ICC) of 0.90 (0.77-0.96) and 0.99 (0.98-1.0), respectively. Regarding inter-observer validity, the ICCs for the first and second measurements were 0.90 (range, 0.77-0.96) and 0.95 (range, 0.85-0.98), respectively. Conclusion CT volumetry is a reliable and reproducible method for measurement of transplanted pancreatic volume.

  9. Accuracy of MRI volume measurements of breast lesions: comparison between automated, semiautomated and manual assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rominger, Marga B.; Fournell, Daphne; Nadar, Beenarose Thanka; Figiel, Jens H.; Keil, Boris; Heverhagen, Johannes T. [Philipps University, Department of Radiology, Marburg (Germany); Behrens, Sarah N.M. [MeVis GmbH, Bremen (Germany)

    2009-05-15

    The aim of this study was to investigate the efficacy of a dedicated software tool for automated and semiautomated volume measurement in contrast-enhanced (CE) magnetic resonance mammography (MRM). Ninety-six breast lesions with histopathological workup (27 benign, 69 malignant) were re-evaluated by different volume measurement techniques. Volumes of all lesions were extracted automatically (AVM) and semiautomatically (SAVM) from CE 3D MRM and compared with manual 3D contour segmentation (manual volume measurement, MVM, reference measurement technique) and volume estimates based on maximum diameter measurement (MDM). Compared with MVM as reference method MDM, AVM and SAVM underestimated lesion volumes by 63.8%, 30.9% and 21.5%, respectively, with significantly different accuracy for benign (102.4%, 18.4% and 11.4%) and malignant (54.9%, 33.0% and 23.1%) lesions (p<0.05). Inter- and intraobserver reproducibility was best for AVM (mean difference {+-}2SD, 1.0{+-}9.7% and 1.8{+-}12.1%) followed by SAVM (4.3{+-}25.7% and 4.3{+-}7.9%), MVM (2.3{+-}38.2% and 8.6{+-}31.8%) and MDM (33.9{+-}128.4% and 9.3{+-}55.9%). SAVM is more accurate for volume assessment of breast lesions than MDM and AVM. Volume measurement is less accurate for malignant than benign lesions. (orig.)

  10. Three-dimensional whole-brain perfused blood volume imaging with multimodal CT for evaluation of acute ischaemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Lu, J.; Zhang, M.; Cao, Y. [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing (China); Ma, Q. [Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing (China); Chen, J. [Healthcare, Siemens Ltd. China, Beijing (China); Ji, X. [Department of Neurosurgery Xuanwu Hospital, Capital Medical University, Beijing (China); Li, K., E-mail: imaging@yeah.ne [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing (China)

    2011-06-15

    Aim: To determine the diagnostic value of integrating three-dimensional perfused blood volume (3D PBV) with multimodal computed tomography (CT) [non-enhanced CT (NECT), CT perfusion (CTP), and CT angiography (CTA)] in acute ischaemic stroke. Materials and methods: NECT, CTP, and CTA were performed in 25 acute ischaemic stroke patients. The ischaemia detection rate of 3D PBV was compared with the results of baseline NECT and CTP. The correlation of ischaemic lesion volume between 3D PBV, CTP images, and follow-up NECT were analysed. Results: NECT demonstrated ischaemic signs in 12 of 25 patients with proven infarction. CTP maps of cerebral blood flow (CBF), cerebral blood volume (CBV), and time to peak (TTP) all demonstrated perfusion deficits in 21 of 25 patients. However, 3D PBV demonstrated perfusion deficits in all of the 25 patients. Among the 25 patients, a strong correlation was found between PBV and the follow-up NECT infarct (r = 0.858). The correlation between CTP and the follow-up NECT infarct as following: CBF (r = 0.718), CBV (r = 0.785), and TTP (r = 0.569). In 14 thrombolytic patients, strong correlation was found between the ischaemic volume on 3D PBV and follow-up NECT (r = 0.798). Conclusion: In acute stroke patients, the combination of 3D PBV and multimodal CT (NECT, CTP, and CTA) can improve the detection rate of ischaemia and enable assessment of the full extent of ischaemia, which correlates well with follow-up NECT.

  11. Methodological aspects of blood pressure measurement and adherence to antihypertensive drug therapy

    NARCIS (Netherlands)

    Braam, R.L.

    2007-01-01

    Hypertension is an important risk-factor for cardiovascular disease. Accurate blood pressure measurements are very important to diagnose hypertension. Nowadays these blood pressure measurements are often performed using automatic devices. One can wonder whether these devices are accurate enough. In

  12. Acute Effects of Caffeine on Heart Rate Variability, Blood Pressure and Tidal Volume in Paraplegic and Tetraplegic Compared to Able-Bodied Individuals: A Randomized, Blinded Trial

    Science.gov (United States)

    Flueck, Joelle Leonie; Schaufelberger, Fabienne; Lienert, Martina; Schäfer Olstad, Daniela; Wilhelm, Matthias; Perret, Claudio

    2016-01-01

    Caffeine increases sympathetic nerve activity in healthy individuals. Such modulation of nervous system activity can be tracked by assessing the heart rate variability. This study aimed to investigate the influence of caffeine on time- and frequency-domain heart rate variability parameters, blood pressure and tidal volume in paraplegic and tetraplegic compared to able-bodied participants. Heart rate variability was measured in supine and sitting position pre and post ingestion of either placebo or 6 mg caffeine in 12 able-bodied, 9 paraplegic and 7 tetraplegic participants in a placebo-controlled, randomized and double-blind study design. Metronomic breathing was applied (0.25 Hz) and tidal volume was recorded during heart rate variability assessment. Blood pressure, plasma caffeine and epinephrine concentrations were analyzed pre and post ingestion. Most parameters of heart rate variability did not significantly change post caffeine ingestion compared to placebo. Tidal volume significantly increased post caffeine ingestion in able-bodied (p = 0.021) and paraplegic (p = 0.036) but not in tetraplegic participants (p = 0.34). Systolic and diastolic blood pressure increased significantly post caffeine in able-bodied (systolic: p = 0.003; diastolic: p = 0.021) and tetraplegic (systolic: p = 0.043; diastolic: p = 0.042) but not in paraplegic participants (systolic: p = 0.09; diastolic: p = 0.33). Plasma caffeine concentrations were significantly increased post caffeine ingestion in all three groups of participants (p<0.05). Plasma epinephrine concentrations increased significantly in able-bodied (p = 0.002) and paraplegic (p = 0.032) but not in tetraplegic participants (p = 0.63). The influence of caffeine on the autonomic nervous system seems to depend on the level of lesion and the extent of the impairment. Therefore, tetraplegic participants may be less influenced by caffeine ingestion. Trial Registration ClinicalTrials.gov NCT02083328 PMID:27776149

  13. Adult derived genetic blood pressure scores and blood pressure measured in different body postures in young children

    NARCIS (Netherlands)

    Jansen, Maria Ac; Dalmeijer, Geertje W.; Visseren, Frank Lj; van der Ent, Cornelis K; Leusink, Maarten; Onland-Moret, N Charlotte; Der Zee, Anke H Maitland Van; Grobbee, Diederick E; Uiterwaal, CSPM

    2017-01-01

    Aims Several genes are related to blood pressure (BP) levels in adults, but it is largely unknown whether these genes also determine BP early in life. Methods Systolic BP (SBP) and diastolic BP (DBP) were measured in 720 5-year-old children from the WHeezing-Illnesses-STudy-LEidsche-Rijn (WHISTLER)

  14. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

    Science.gov (United States)

    Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

    2010-03-01

    Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

  15. Reliability and validity of the lung volume measurement made by the BOD POD body composition system.

    Science.gov (United States)

    Davis, James A; Dorado, Silvia; Keays, Kathleen A; Reigel, Kimberly A; Valencia, Kristoffer S; Pham, Patrick H

    2007-01-01

    The BOD POD Body Composition System uses air-displacement plethysmography to measure body volume. To correct the body volume measurement for the subject's lung volume, the BOD POD utilizes pulmonary plethysmography to measure functional residual capacity (FRC) at mid-exhalation as that is the subject's lung volume during the body volume measurement. Normally, FRC is measured at end-exhalation. The BOD POD FRC measurement can be corrected to an end-exhalation volume by subtracting approximately one-half of the measured tidal volume. Our purpose was to determine the reliability and validity of the BOD POD FRC measurement at end-exhalation. Ninety-two healthy adults (half female) underwent duplicate FRC measurements by the BOD POD and one FRC measurement by a traditional gas dilution technique. The latter method was used as the reference method for the validity component of the study. The order of the FRC measurements by the two methods was randomized. The test-retest correlation coefficients for the duplicate BOD POD FRC measurements for the male and female subjects were 0.966 and 0.948, respectively. The mean differences between the BOD POD FRC trial #1 measurement and gas dilution FRC measurement for the male and female subjects were -32 and -23 ml, respectively. Neither difference was statistically significant. The correlation coefficients for these two measurements in the male and female subjects were 0.925 and 0.917, respectively. Based on these results, we conclude that the BOD POD FRC measurement in healthy males and females is both reliable and valid.

  16. Automated measurement of local white matter lesion volume

    DEFF Research Database (Denmark)

    van der Lijn, Fedde; Verhaaren, Benjamin F. J.; Ikram, M. Arfan;

    2012-01-01

    . The method was also compared to two commonly used techniques to assess the periventricular and subcortical lesion load. The main finding was that high blood pressure was primarily associated with lesion load in the vascular watershed area that forms the border between the periventricular and subcortical...... regions. It explains the associations found for both the periventricular and subcortical load computed for the same data, and that were reported in the literature. But the proposed method can localize the region of association with greater precision than techniques that distinguish between periventricular...

  17. SMN Protein Can Be Reliably Measured in Whole Blood with an Electrochemiluminescence (ECL Immunoassay: Implications for Clinical Trials.

    Directory of Open Access Journals (Sweden)

    Phillip Zaworski

    Full Text Available Spinal muscular atrophy (SMA is caused by defects in the survival motor neuron 1 (SMN1 gene that encodes survival motor neuron (SMN protein. The majority of therapeutic approaches currently in clinical development for SMA aim to increase SMN protein expression and there is a need for sensitive methods able to quantify increases in SMN protein levels in accessible tissues. We have developed a sensitive electrochemiluminescence (ECL-based immunoassay for measuring SMN protein in whole blood with a minimum volume requirement of 5μL. The SMN-ECL immunoassay enables accurate measurement of SMN in whole blood and other tissues. Using the assay, we measured SMN protein in whole blood from SMA patients and healthy controls and found that SMN protein levels were associated with SMN2 copy number and were greater in SMA patients with 4 copies, relative to those with 2 and 3 copies. SMN protein levels did not vary significantly in healthy individuals over a four-week period and were not affected by circadian rhythms. Almost half of the SMN protein was found in platelets. We show that SMN protein levels in C/C-allele mice, which model a mild form of SMA, were high in neonatal stage, decreased in the first few weeks after birth, and then remained stable throughout the adult stage. Importantly, SMN protein levels in the CNS correlated with SMN levels measured in whole blood of the C/C-allele mice. These findings have implications for the measurement of SMN protein induction in whole blood in response to SMN-upregulating therapy.

  18. Monte Carlo method with heuristic adjustment for irregularly shaped food product volume measurement.

    Science.gov (United States)

    Siswantoro, Joko; Prabuwono, Anton Satria; Abdullah, Azizi; Idrus, Bahari

    2014-01-01

    Volume measurement plays an important role in the production and processing of food products. Various methods have been proposed to measure the volume of food products with irregular shapes based on 3D reconstruction. However, 3D reconstruction comes with a high-priced computational cost. Furthermore, some of the volume measurement methods based on 3D reconstruction have a low accuracy. Another method for measuring volume of objects uses Monte Carlo method. Monte Carlo method performs volume measurements using random points. Monte Carlo method only requires information regarding whether random points fall inside or outside an object and does not require a 3D reconstruction. This paper proposes volume measurement using a computer vision system for irregularly shaped food products without 3D reconstruction based on Monte Carlo method with heuristic adjustment. Five images of food product were captured using five cameras and processed to produce binary images. Monte Carlo integration with heuristic adjustment was performed to measure the volume based on the information extracted from binary images. The experimental results show that the proposed method provided high accuracy and precision compared to the water displacement method. In addition, the proposed method is more accurate and faster than the space carving method.

  19. Smartphone-based Continuous Blood Pressure Measurement Using Pulse Transit Time.

    Science.gov (United States)

    Gholamhosseini, Hamid; Meintjes, Andries; Baig, Mirza; Linden, Maria

    2016-01-01

    The increasing availability of low cost and easy to use personalized medical monitoring devices has opened the door for new and innovative methods of health monitoring to emerge. Cuff-less and continuous methods of measuring blood pressure are particularly attractive as blood pressure is one of the most important measurements of long term cardiovascular health. Current methods of noninvasive blood pressure measurement are based on inflation and deflation of a cuff with some effects on arteries where blood pressure is being measured. This inflation can also cause patient discomfort and alter the measurement results. In this work, a mobile application was developed to collate the PhotoPlethysmoGramm (PPG) waveform provided by a pulse oximeter and the electrocardiogram (ECG) for calculating the pulse transit time. This information is then indirectly related to the user's systolic blood pressure. The developed application successfully connects to the PPG and ECG monitoring devices using Bluetooth wireless connection and stores the data onto an online server. The pulse transit time is estimated in real time and the user's systolic blood pressure can be estimated after the system has been calibrated. The synchronization between the two devices was found to pose a challenge to this method of continuous blood pressure monitoring. However, the implemented continuous blood pressure monitoring system effectively serves as a proof of concept. This combined with the massive benefits that an accurate and robust continuous blood pressure monitoring system would provide indicates that it is certainly worthwhile to further develop this system.

  20. Effects of 5-HT1B/1D receptor agonist rizatriptan on cerebral blood flow and blood volume in normal circulation.

    Science.gov (United States)

    Okazawa, Hidehiko; Tsuchida, Tatsuro; Pagani, Marco; Mori, Tetsuya; Kobayashi, Masato; Tanaka, Fumiko; Yonekura, Yoshiharu

    2006-01-01

    To investigate the vasoconstrictor effect of 5-hydroxytryptamine (5-HT1B/1D) receptor agonists for migraine treatment, changes in cerebral blood flow (CBF) and blood volume induced by rizatriptan were assessed by positron emission tomography (PET). Eleven healthy volunteers underwent PET studies before and after rizatriptan administration. Dynamic PET data were acquired after bolus injection of H2(15)O to analyze CBF and arterial-to-capillary blood volume (V0) images using the three-weighted integral method. After a baseline scan, three further acquisitions were performed at 40 to 50, 60 and 70 to 80 mins after drug administration. Global and regional differences in CBF and V0 between conditions were compared using absolute values in the whole brain and cortical regions, as well as statistical parametric mapping (SPM) analysis. The global and regional values for CBF and V0 decreased significantly after rizatriptan administration compared with the baseline condition. However, both values recovered to baseline within 80 mins after treatment. The maximal reduction in global CBF and V0 was approximately 13% of baseline value. The greatest decrease in CBF was observed approximately 60 mins after drug administration, whereas the maximal reduction in V0 was observed approximately 5 mins earlier. Statistical parametric mapping did not highlight any regional differences between conditions. Thus, in brain circulation, rizatriptan caused significant CBF and V0 decreases, which are consistent with the vasoconstrictor effect of triptans on the large cerebral arteries. The gradual recovery in the late phase from the maximal CBF and V0 decrease suggests that rizatriptan does not affect the cerebral autoregulatory response in small arteries induced by CBF reduction.

  1. Attempts to Improve Absolute Quantification of Cerebral Blood Flow in Dynamic Susceptibility Contrast Magnetic Resonance Imaging: A Simplified T1-Weighted Steady-State Cerebral Blood Volume Approach

    Energy Technology Data Exchange (ETDEWEB)

    Wirestam, R.; Knutsson, L.; Risberg, J.; Boerjesson, S.; Larsson, E.M.; Gustafson, L.; Passant, U.; Staahlberg, F. [Depts. of Medical Radiation Physics, Diagnostic Radiology, Psychiatry, and Psychogeriatrics, Lund Univ, Lund (Sweden)

    2007-07-15

    Background: Attempts to retrieve absolute values of cerebral blood flow (CBF) by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) have typically resulted in overestimations. Purpose: To improve DSC-MRI CBF estimates by calibrating the DSC-MRI-based cerebral blood volume (CBV) with a corresponding T1-weighted (T1W) steady-state (ss) CBV estimate. Material and Methods: 17 volunteers were investigated by DSC-MRI and 133Xe SPECT. Steady-state CBV calculation, assuming no water exchange, was accomplished using signal values from blood and tissue, before and after contrast agent, obtained by T1W spin-echo imaging. Using steady-state and DSC-MRI CBV estimates, a calibration factor K = CBV(ss)/CBV(DSC) was obtained for each individual. Average whole-brain CBF(DSC) was calculated, and the corrected MRI-based CBF estimate was given by CBF(ss) = KxCBF(DSC). Results: Average whole-brain SPECT CBF was 40.1{+-}6.9 ml/min 100 g, while the corresponding uncorrected DSC-MRI-based value was 69.2{+-}13.8 ml/mi 100 g. After correction with the calibration factor, a CBF(ss) of 42.7{+-}14.0 ml/min 100 g was obtained. The linear fit to CBF(ss)-versus-CBF(SPECT) data was close to proportionality (R = 0.52). Conclusion: Calibration by steady-state CBV reduced the population average CBF to a reasonable level, and a modest linear correlation with the reference 133Xe SPECT technique was observed. Possible explanations for the limited accuracy are, for example, large-vessel partial-volume effects, low post-contrast signal enhancement in T1W images, and water-exchange effects.

  2. Ocular Blood Flow Measured Noninvasively in Zero Gravity

    Science.gov (United States)

    Ansari, Rafat R.; Manuel, Francis K.; Geiser, Martial; Moret, Fabrice; Messer, Russell K.; King, James F.; Suh, Kwang I.

    2003-01-01

    In spaceflight or a reduced-gravity environment, bodily fluids shift to the upper extremities of the body. The pressure inside the eye, or intraocular pressure, changes significantly. A significant number of astronauts report changes in visual acuity during orbital flight. To date this remains of unknown etiology. Could choroidal engorgement be the primary mechanism and a change in the curvature or shape of the cornea or lens be the secondary mechanism for this change in visual acuity? Perfused blood flow in the dense meshwork of capillaries of the choroidal tissue (see the preceding illustration) provides necessary nutrients to the outer layers of the retina (photoreceptors) to keep it healthy and maintain good vision. Unlike the vascular system, the choroid has no baroreceptors to autoregulate fluid shifts, so it can remain engorged, pushing the macula forward and causing a hyperopic (farsighted) shift of the eye. Experiments by researchers at the NASA Glenn Research Center could help answer this question and facilitate planning for long-duration missions. We are investigating the effects of zero gravity on the choroidal blood flow of volunteer subjects. This pilot project plans to determine if choroidal blood flow is autoregulated in a reduced-gravity environment.

  3. Evaluation of liver functional reserve by combining D-sorbitol clearance rate and CT measured liver volume

    Institute of Scientific and Technical Information of China (English)

    Yi-Ming Li; Fan Lv; Xin Xu; Hong Ji; Wen-Tao Gao; Tuan-Jie Lei; Gui-Bing Ren; Zhi-Lan Bai; Qiang Li

    2003-01-01

    AIM: Our research attempted to evaluate the overall functional reserve of cirrhotic liver by combination of hepatic functional blood flow, liver volume, and ChildPugh′s classification, and to discuss its value of clinical application.METHODS: Ninety two patients with portal hypertension due to hepatic cirrhosis were investigated. All had a historyof haematemesis and hematochezia, esophageal and gastric fundus varices, splenomegaly and hypersplenia.A 2-year follow-up was routinely performed and no one was lost. Twenty two healthy volunteers were used as control group. Blood and urine samples were collected 4times before and after intravenous D-sorbitol infusion.The hepatic clearance (CLH) of D-sorbitol was then calculated according to enzymatic spectrophotometric method while the total blood flow (QToTAL) and intrahepatic shunt (RINs) were detected by multicolor Doppler ultrasound, and the liver volume was measured by spiral CT. Data were estimated by t-test, variance calculation and chi-squared test. The relationships between all these parameters and different groups were investigated according to Child-Pugh classification and postoperative complications respectively.RESULTS: Steady blood concentration was achieved 120 mins after D-sorbitol intravenous infusion, which was (0.358±0.064) mmoⅠ@L-1 in cirrhotic group and (0.189±0.05)mmol@L-1 in control group (P<0.01). CLH=(812.7±112.4) ml@min-1,QTOTAL=(1280.6±131.4) ml@min-1, and RINS=(36.54±10.65)%in cirrhotic group and CLH=(1248.3±210.5) ml.min-1, QTOTAL=(1362.4-±126.9) ml@min-1, and RINS=(8.37±3.32) % in control group (P<0.01). The liver volume of cirrhotic group was 1057±249 cm3, 851±148 cm3 and 663±77 cm3 in Child A, B and C group respectively with significant difference (P<0.001).The average volume of cirrhotic liver in Child B, C group was significantly reduced in comparison with that in control group (P<0.001). The patient, whose liver volume decreased by 40 % with the CLH below 600 ml

  4. Integrated analysis of halogenated organic pollutants in sub-millilitre volumes of venous and umbilical cord blood sera

    Energy Technology Data Exchange (ETDEWEB)

    Grimalt, Joan O.; Carrizo, Daniel; Otero, Raquel; Vizcaino, Esther [Institute of Environmental Assessment and Water Research (IDAeA-CSIC), Department of Environmental Chemistry, Barcelona, Catalonia (Spain); Howsam, Mike [Universite de Lille 2, Centre Universitaire de Mesure et d' Analyse, Faculte de Pharmacie, Lille (France); Rodrigues de Marchi, Mary Rosa [Institute of Chemistry UNESP, Department of Analytical Chemistry, Araraquara, SP (Brazil)

    2010-03-15

    A rapid, robust and economical method for the analysis of persistent halogenated organic compounds in small volumes of human serum and umbilical cord blood is described. The pollutants studied cover a broad range of molecules of contemporary epidemiological and legislative concern, including polychlorobiphenyls (PCBs), polychlorobenzenes (CBs), hexachlorocyclohexanes (HCHs), DDTs, polychlorostyrenes (PCSs) and polybromodiphenyl ethers (PBDEs). Extraction and clean-up with n-hexane and concentrated sulphuric acid was followed with analysis by gas chromatography coupled to electron capture (GC-ECD) and GC coupled to negative ion chemical ionisation mass spectrometry (GC-NICI-MS). The advantages of this method rest in the broad range of analytes and its simplicity and robustness, while the use of concentrated sulphuric acid extraction/clean-up destroys viruses that may be present in the samples. Small volumes of reference serum between 50 and 1000{mu}L were extracted and the limits of detection/quantification and repeatability were determined. Recoveries of spiked compounds for the extraction of small volumes ({>=}300 {mu}L) of the spiked reference serum were between 90% and 120%. The coefficients of variation of repeatability ranged from 0.1-14%, depending on the compound. Samples of 4-year-old serum and umbilical cord blood (n=73 and 40, respectively) from a population inhabiting a village near a chloro-alkali plant were screened for the above-mentioned halogenated pollutants using this method and the results are briefly described. (orig.)

  5. The effect of blood volume loss on cardiovascular response to lower body negative pressure using a mathematical model

    Science.gov (United States)

    Karam, E. H.; Srinivasan, R. S.; Charles, J. B.; Fortney, S. M.

    1994-01-01

    Different mathematical models of varying complexity have been proposed in recent years to study the cardiovascular (CV) system. However, only a few of them specifically address the response to lower body negative pressure (LBNP), a stress that can be applied in weightlessness to predict changes in orthostatic tolerance. Also, the simulated results produced by these models agree only partially with experimental observations. In contrast, the model proposed by Melchior et al., and modified by Karam et al. is a simple representation of the CV system capable of accurately reproducing observed LBNP responses up to presyncopal levels. There are significant changes in LBNP response due to a loss of blood volume and other alterations that occur in weightlessness and related one-g conditions such as bedrest. A few days of bedrest can cause up to 15% blood volume loss (BVL), with consequent decreases in both stroke volume and cardiac output, and increases in heart rate, mean arterial pressure, and total peripheral resistance. These changes are more pronounced at higher levels of LBNP. This paper presents the results of a simulation study using our CV model to examine the effect of BVL on LBNP response.

  6. Increased apparatus dead space and tidal volume increase blood concentrations of oxygen and sevoflurane in overweight patients: a randomised controlled clinical study.

    OpenAIRE

    Enekvist, Bruno; Bodelsson, Mikael; Johansson, Anders

    2011-01-01

    General anaesthesia impairs respiratory function in overweight patients. We wanted to determine whether increased tidal volume (VT), with unchanged end-tidal carbon dioxide partial pressure (PETCO2), affects blood concentrations of oxygen and sevoflurane in overweight patients.

  7. Feasibility of the left ventricular volume measurement by acoustic quantification method. Comparison with ultrafast computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tomimoto, Shigehiro; Nakatani, Satoshi; Tanaka, Norio; Uematsu, Masaaki; Beppu, Shintaro; Nagata, Seiki; Hamada, Seiki; Takamiya, Makoto; Miyatake, Kunio [National Cardiovascular Center, Suita, Osaka (Japan)

    1995-01-01

    Acoustic quantification (AQ: the real-time automated boundary detection system) allows instantaneous measurement of cardiac chamber volumes. The feasibility of this method was evaluated by comparing the left ventricular (LV) volumes obtained with AQ to those derived from ultrafast computed tomography (UFCT), which enables accurate measurements of LV volumes even in the presence of LV asynergy, in 23 patients (8 with ischemic heart disease, 5 with cardiomyopathy, 3 with valvular heart disease). Both LV end-diastolic and end-systolic volumes obtained with the AQ method were in good agreement with those obtained with UFCT (y=1.04{chi}-16.9, r=0.95; y=0.87{chi}+15.7, r=0.91; respectively). AQ was reliable even in the presence of LV asynergy. Interobserver variability for the AQ measurement was 10.2%. AQ provides a new, clinically useful method for real-time accurate estimation of the left ventricular volume. (author).

  8. A rapid liquid chromatography tandem mass spectrometry-based method for measuring propranolol on dried blood spots.

    Science.gov (United States)

    Della Bona, Maria Luisa; Malvagia, Sabrina; Villanelli, Fabio; Giocaliere, Elisa; Ombrone, Daniela; Funghini, Silvia; Filippi, Luca; Cavallaro, Giacomo; Bagnoli, Paola; Guerrini, Renzo; la Marca, Giancarlo

    2013-05-05

    Propranolol, a non-selective beta blocker drug, is used in young infants and newborns for treating several heart diseases; its pharmacokinetics has been extensively evaluated in adult patients using extrapolation to treat pediatric population. The purpose of the present study was to develop and validate a method to measure propranolol levels in dried blood spots. The analysis was performed by using liquid chromatography/tandem mass spectrometry operating in multiple reaction monitoring mode. The calibration curve in matrix was linear in the concentration range of 2.5-200 μg/L with correlation coefficient r=0.9996. Intra-day and inter-day precisions and biases were less than 8.0% (n=10) and 11.5% (n=10) respectively. The recoveries ranged from 94 to 100% and the matrix effect did not result in a severe signal suppression. Propranolol on dried blood spot showed a good stability at three different temperatures for one month. This paper describes a micromethod for measuring propranolol levels on dried blood spot, which determines a great advantage in neonates or young infants during pharmacokinetic studies because of less invasive sampling and small blood volume required.

  9. Practical do-it-yourself device for accurate volume measurement of breast.

    Science.gov (United States)

    Tezel, E; Numanoğlu, A

    2000-03-01

    A simple and accurate method of measuring differences in breast volume based on Archimedes' principle is described. In this method, a plastic container is placed on the breast of the patient who is lying in supine position. While the breast occupies part of the container, the remaining part is filled with water and the volume is measured. This method allows the measurement of the volume differences of asymmetric breasts and also helps the surgeon to estimate the size of the prosthesis to be used in augmentation mammaplasty.

  10. Enhanced Stability of Blood Matrices Using a Dried Sample Spot Assay to Measure Human Butyrylcholinesterase Activity and Nerve Agent Adducts

    Science.gov (United States)

    Perez, Jonas W.; Pantazides, Brooke G.; Watson, Caroline M.; Thomas, Jerry D.; Blake, Thomas A.; Johnson, Rudolph C.

    2015-01-01

    Dried matrix spots are safer to handle and easier to store than wet blood products, but factors such as intra-spot variability and unknown sample volumes have limited their appeal as a sampling format for quantitative analyses. In this work, we introduce a dried spot activity assay for quantifying butyrylcholinesterase (BChE) specific activity which is BChE activity normalized to the total protein content in a sample spot. The method was demonstrated with blood, serum, and plasma spotted on specimen collection devices (cards) which were extracted to measure total protein and BChE activity using a modified Ellman assay. Activity recovered from dried spots was ∼80% of the initial spotted activity for blood and >90% for plasma and serum. Measuring total protein in the sample and calculating specific activity substantially improved quantification and reduced intra-spot variability. Analyte stability of nerve agent adducts was also evaluated, and the results obtained via BChE-specific activity measurements were confirmed by quantification of BChE adducts using a previously established LC-MS/MS method. The spotted samples were up to 10-times more resistant to degradation compared to unspotted control samples when measuring BChE inhibition by the nerve agents sarin and VX. Using this method, both BChE activity and adducts can be accurately measured from a dried sample spot. This use of a dried sample spot with normalization to total protein is robust, demonstrates decreased intra-spot variability without the need to control for initial sample volume, and enhances analyte stability. PMID:25955132

  11. High-speed volume measurement system and method

    Science.gov (United States)

    Lane, Michael H.; Doyle, Jr., James L.; Brinkman, Michael J.

    2015-11-24

    Disclosed is a volume sensor having first, second, and third laser sources emitting first, second, and third laser beams; first, second, and third beam splitters splitting the first, second, and third laser beams into first, second, and third beam pairs; first, second, and third optical assemblies expanding the first, second, and third beam pairs into first, second, and third pairs of parallel beam sheets; fourth, fifth, and sixth optical assemblies focusing the first, second, and third beam sheet pairs into fourth, fifth, and sixth beam pairs; and first, second, and third detector pairs receiving the fourth, fifth, and sixth beam pairs and converting a change in intensity of at least one of the beam pairs resulting from an object passing through at least one of the first, second, and third parallel beam sheets into at least one electrical signal proportional to a three-dimensional representation of the object.

  12. Dedicated breast CT: Fibroglandular volume measurements in a diagnostic population

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, Srinivasan; Shi Linxi; Karellas, Andrew; O' Connell, Avice M. [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States); Department of Imaging Sciences, University of Rochester Medical Center, Rochester, New York 14642 (United States)

    2012-12-15

    Purpose: To determine the mean and range of volumetric glandular fraction (VGF) of the breast in a diagnostic population using a high-resolution flat-panel cone-beam dedicated breast CT system. This information is important for Monte Carlo-based estimation of normalized glandular dose coefficients and for investigating the dependence of VGF on breast dimensions, race, and pathology. Methods: Image data from a clinical trial investigating the role of dedicated breast CT that enrolled 150 women were retrospectively analyzed to determine the VGF. The study was conducted in adherence to a protocol approved by the institutional human subjects review boards and written informed consent was obtained from all study participants. All participants in the study were assigned BI-RADS{sup Registered-Sign} 4 or 5 as per the American College of Radiology assessment categories after standard diagnostic work-up and underwent dedicated breast CT exam prior to biopsy. A Gaussian-kernel based fuzzy c-means algorithm was used to partition the breast CT images into adipose and fibroglandular tissue after segmenting the skin. Upon determination of the accuracy of the algorithm with a phantom, it was applied to 137 breast CT volumes from 136 women. VGF was determined for each breast and the mean and range were determined. Pathology results with classification as benign, malignant, and hyperplasia were available for 132 women, and were used to investigate if the distributions of VGF varied with pathology. Results: The algorithm was accurate to within {+-}1.9% in determining the volume of an irregular shaped phantom. The study mean ({+-} inter-breast SD) for the VGF was 0.172 {+-} 0.142 (range: 0.012-0.719). VGF was found to be negatively correlated with age, breast dimensions (chest-wall to nipple length, pectoralis to nipple length, and effective diameter at chest-wall), and total breast volume, and positively correlated with fibroglandular volume. Based on pathology, pairwise statistical

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

    Science.gov (United States)

    Antoine, Elizabeth; Buchanan, Cara; Fezzaa, Kamel; Lee, Wah-Keat; Rylander, M Nichole; Vlachos, Pavlos

    2013-01-01

    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.

  14. 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.

  15. Variation in Measurements of Transtibial Stump Model Volume A Comparison of Five Methods

    NARCIS (Netherlands)

    Bolt, A.; de Boer-Wilzing, V. G.; Geertzen, J. H. B.; Emmelot, C. H.; Baars, E. C. T.; Dijkstra, P. U.

    2010-01-01

    Objective: To determine the right moment for fitting the first prosthesis, it is necessary to know when the volume of the stump has stabilized. The aim of this study is to analyze variation in measurements of transtibial stump model volumes using the water immersion method, the Design TT system, the

  16. Double-echo perfusion-weighted MR imaging: basic concepts and application in brain tumors for the assessment of tumor blood volume and vascular permeability

    OpenAIRE

    Uematsu, Hidemasa; Maeda, Masayuki

    2006-01-01

    Perfusion-weighted magnetic resonance (MR) imaging using contrast agents plays a key role in characterizing tumors of the brain. We have shown that double-echo perfusion-weighted MR imaging (DEPWI) is potentially useful in assessing brain tumors. Quantitative indices, such as tumor blood volume, are obtained using DEPWI, which allows correction of underestimation of tumor blood volume due to leakage of contrast agents from tumor vessels, in addition to simultaneous acquisition of tumor vessel...

  17. Proportion and characteristics of patients who measure their blood pressure at home: Nationwide survey in Slovenia

    Directory of Open Access Journals (Sweden)

    Petek-Šter Marija

    2009-01-01

    Full Text Available Introduction. Home blood pressure monitoring has several advantages over blood pressure monitoring at a physician's office, and has become a useful instrument in the management of hypertension. Objective. To explore the rate and characteristics of patients who measure their blood pressure at home. Methods. A sample of 2,752 patients with diagnosis of essential arterial hypertension was selected from 12596 consecutive office visitors. Data of 2,639 patients was appropriate for analysis. The data concerning home blood pressure measurement and patients' characteristics were obtained from the patients' case histories. Results 1,835 (69.5% out of 2,639 patients measured their blood pressure at home. 1,284 (70.0% of home blood pressure patients had their own blood pressure measurement device. There were some important differences between these two groups: home blood pressure patients were more frequently male, of younger age, better educated, from urban area, mostly non-smokers, more likely to have diabetes mellitus and ischemic heart disease and had higher number of co-morbidities and were on other drugs beside antihypertensive medication. Using the logistic regression analysis we found that the most powerful predictors of home blood pressure monitoring had higher education level than primary school OR=1.80 (95% CI 1.37-2.37, non-smoking OR=2.16 (95% CI 1.40-3.33 and having a physician in urban area OR=1.32 (95% CI 1.02-1.71. Conclusion. Home blood pressure monitoring is popular in Slovenia. Patients who measured blood pressure at home were different from patients who did not. Younger age, higher education, non-smoking, having a physician in urban area and longer duration of hypertension were predictors of home blood pressure monitoring.

  18. Molar Volume Analysis of Molten Ni-Al-Co Alloy by Measuring the Density

    Institute of Scientific and Technical Information of China (English)

    XIAO Feng; FANG Liang; FU Yuechao; YANG Lingchuan

    2004-01-01

    The density of molten Ni-Al-Co alloys was measured in the temperature range of 1714~1873K using a modified pycnometric method, and the molar volume of molten alloys was analyzed. The density of molten Ni-Al-Co alloys was found to decrease with increasing temperature and Co concentration in alloys. The molar volume of molten Ni-Al-Co alloys increases with increasing Co concentration in alloys. The molar volume of molten Ni-Al-Co alloys shows a negative deviation from the linear molar volume.

  19. Closure of digital arteries in high vascular tone states as demonstrated by measurement of systolic blood pressure in the fingers

    DEFF Research Database (Denmark)

    Krähenbühl, B; Nielsen, S L; Lassen, N A

    1977-01-01

    Finger systolic blood pressure (FSP) was measured indirectly in normal subjects and patients with primary Raynaud phenomenon by applying a thin-walled plastic cuff around the finger and a strain gauge more distally to detect volume changes. Inducing a high vascular tone in one or more fingers...... by direct cooling or intra-arterial noradrenaline infusion caused a marked drop in FSP in the exposed fingers, but not in the non-exposed fingers of the same hand. The fact that the non-exposed fingers retained the normal (arm systolic) pressure level is taken to indicate that palmar arch blood pressure...... also remained normal. In the high vascular tone state, a large transmural pressure difference must apparently be established before the digital arteries are forced open. The lowered opening pressure constitutes a manifestation of the closure phenomenon of the digital arteries described in patients...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

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

  1. Measurement of human blood viscosity by an electromagnetic spinning sphere viscometer.

    Science.gov (United States)

    Furukawa, Koji; Abumiya, Takeo; Sakai, Keiji; Hirano, Miki; Osanai, Toshiya; Shichinohe, Hideo; Nakayama, Naoki; Kazumata, Ken; Aida, Toshimitsu; Houkin, Kiyohiro

    2016-08-01

    We herein applied an electromagnetic spinning sphere (EMS) viscometer to the measurement of human blood viscosity for the first time. We collected blood samples from 100 healthy outpatient volunteers in order to analyse viscosity dependence on blood cell parameters and on the shear rate with a simple approximation formula [ηi (γ)\\, = Ai γ(- pi) + η0]. Viscosity dependence on blood cell parameters was relatively high at a high shear rate, but became lower as the shear rate decreased. The approximation formula with appropriate parameters of Ai and pi nearly faithfully reproduced actual blood rheological behaviour with a standard deviation of 1.5%. The distributions of Ai and pi values were broad, suggesting that the pattern of viscosity dependence on the shear rate varied with individual differences. The results obtained using the EMS viscometer suggest that blood viscosity values are individual-specific and actual individual measurements are important for understanding rheological conditions.

  2. The application of blood flow measurements to the study of aging muscle.

    Science.gov (United States)

    McCully, K K; Posner, J D

    1995-11-01

    Blood flow to skeletal muscle is a potentially important factor in the reduction of muscle function associated with aging (sarcopenia). The main influence of reduced blood flow capacity on muscle function is in limiting oxidative metabolism. Direct measures of blood flow include: intravital-microscopy, plethysmography, radioactive microspheres, 133Xenon washout, thermodilution, and Doppler ultrasound. Indirect measurement of blood flow includes arm-to-ankle pressure index and the rate of phosphocreatine recovery after exercise. Several new methodologies have been developed to evaluate muscle blood flow, including color-Doppler imaging, magnetic resonance imaging/angiography (MRI/MRA), and near-infrared spectroscopy (NIRS). As adaptations of traditional techniques, these methods promise more precise information under less invasive conditions. MRI is an expensive and technically challenging method able to measure vessel location, blood flow, and wall diameter in blood vessels throughout the cardiac cycle. Color-Doppler provides excellent temporal resolution blood flow throughout the cardiac cycle, along with some anatomical information. NIRS is an inexpensive and portable technology that can measure changes in oxygen saturation and provide information on tissue oxygen delivery in studies of frailer and more difficult-to-study subjects. Muscle blood flow is not thought to limit oxidative metabolism under normal conditions in young individuals. However, it is not clear what happens to muscle blood flow in healthy older individuals. Reduced capillary density, less maximal blood flow, and a slower hyperemic flow response have been reported in some, but not all, studies. Further studies with the newer methodologies are needed to re-examine age-related changes in muscle blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Comparison of Blood Cholesterol Profiles Before and After The Measurements of Maximum Aerobic Capacity (VO2max

    Directory of Open Access Journals (Sweden)

    Ar Rasyid Shadiqin

    2013-11-01

    Full Text Available This study is aimed to compare the blood cholesterol profile, before and after the measurement of maximum aerobic capacity (VO2max in the students of Jurusan Pendidikan Olahraga dan Kesehatan (JPOK pada Fakultas Keguruan dan Ilmu Pendidikan (FKIP Universitas Lambung Mangkurat Banjarmasin.Variables in this study consist of lipid profiles, including total cholesterol, high density lipoprotein (HDL, low density lipoprotein (LDL, triglyceride (TG and Maximum Aerobic Capacity (VO2max. The concept of VO2max according to Kent(1994:268: “maximum oxygen volume consumed per minute to show total work capacity, or volume per minute relative to body weight (ml/kg.min”. Operationally, VO2max referred in this study is the maximum volume of oxygen that can be consumed per minute, as measured at progressive run (Bleep Test.The method used in this study is pre-experimental with one group pretest-posttest design. This design implies that a group of subjects are treated for a specific period and the measurements are taken both pre and post.The results: There are changes in blood cholesterol profile after the measurement of maximum oxygen capacity (VO2max, shown by significant decrease of total cholesterol variable, increased HDL, and decreased LDL. Changes in triglyceride variable showed no significant decrease despite the statistic differences. Specific HDL sub-class increasing after exercise is a constructive lipoprotein sub-class whereas LDL is destructive lipoproteins sub-class that might damage the body. Therefore, an increase in HDL and decrease in LDL found in this study appears to be advantageous and consequently might alter the risk of coronary heart disease.

  4. Variation in the measurement of cranial volume and surface area using 3D laser scanning technology.

    Science.gov (United States)

    Sholts, Sabrina B; Wärmländer, Sebastian K T S; Flores, Louise M; Miller, Kevin W P; Walker, Phillip L

    2010-07-01

    Three-dimensional (3D) laser scanner models of human crania can be used for forensic facial reconstruction, and for obtaining craniometric data useful for estimating age, sex, and population affinity of unidentified human remains. However, the use of computer-generated measurements in a casework setting requires the measurement precision to be known. Here, we assess the repeatability and precision of cranial volume and surface area measurements using 3D laser scanner models created by different operators using different protocols for collecting and processing data. We report intraobserver measurement errors of 0.2% and interobserver errors of 2% of the total area and volume values, suggesting that observer-related errors do not pose major obstacles for sharing, combining, or comparing such measurements. Nevertheless, as no standardized procedure exists for area or volume measurements from 3D models, it is imperative to report the scanning and postscanning protocols employed when such measurements are conducted in a forensic setting.

  5. A technique for fast and accurate measurement of hand volumes using Archimedes' principle.

    Science.gov (United States)

    Hughes, S; Lau, J

    2008-03-01

    A new technique for measuring hand volumes using Archimedes principle is described. The technique involves the immersion of a hand in a water container placed on an electronic balance. The volume is given by the change in weight divided by the density of water. This technique was compared with the more conventional technique of immersing an object in a container with an overflow spout and collecting and weighing the volume of overflow water. The hand volume of two subjects was measured. Hand volumes were 494 +/- 6 ml and 312 +/- 7 ml for the immersion method and 476 +/- 14 ml and 302 +/- 8 ml for the overflow method for the two subjects respectively. Using plastic test objects, the mean difference between the actual and measured volume was -0.3% and 2.0% for the immersion and overflow techniques respectively. This study shows that hand volumes can be obtained more quickly than the overflow method. The technique could find an application in clinics where frequent hand volumes are required.

  6. Repeated measurements of blood lactate concentration as a prognostic marker in horses with acute colitis evaluated with classification and regression trees (CART) and random forest analysis.

    Science.gov (United States)

    Petersen, M B; Tolver, A; Husted, L; Tølbøll, T H; Pihl, T H

    2016-07-01

    The objective of this study was to investigate the prognostic value of single and repeated measurements of blood l-lactate (Lac) and ionised calcium (iCa) concentrations, packed cell volume (PCV) and plasma total protein (TP) concentration in horses with acute colitis. A total of 66 adult horses admitted with acute colitis (2 mmol/L (sensitivity, 0.72; specificity, 0.8). In conclusion, blood lactate concentration measured at admission and repeated 6 h later aided the prognostic evaluation of horses with acute colitis in this population with a very high mortality rate. This should allow clinicians to give a more reliable prognosis for the horse.

  7. Limb volume measurement: from the past methods to optoelectronic technologies, bioimpedance analysis and laser based devices.

    Science.gov (United States)

    Cavezzi, A; Schingale, F; Elio, C

    2010-10-01

    Accurate measurement of limb volume is considered crucial to lymphedema management. Various non-invasive methods may be used and have been validated in recent years, though suboptimal standardisation has been highlighted in different publications.

  8. Idaho field experiment 1981. Volume 2: measurement data

    Energy Technology Data Exchange (ETDEWEB)

    Start, G E; Sagendorf, J F; Ackermann, G R; Cate, J H; Hukari, N F; Dickson, C R

    1984-04-01

    The 1981 Idaho Field Experiment was conducted in southeastern Idaho over the upper Snake River Plain. Nine test-day case studies were conducted between July 15 and 30, 1981. Releases of SF/sub 6/ gaseous tracer were made for 8-hour periods from 46m above ground. Tracer was sampled hourly, for 12 sequential hours, at about 100 locations within an area 24km square. Also, a single total integrated sample of about 30 hours duration was collected at approximately 100 sites within an area 48 by 72km square (using 6km spacings). Extensive tower profiles of meteorology at the release point were collected. RAWINSONDES, RABALS and PIBALS were collected at 3 to 5 sites. Horizontal, low-altitude winds were monitored using the INEL MESONET. SF/sub 6/ tracer plume releases were marked with co-located oil fog releases and bi-hourly sequential launches of tetroon pairs. Aerial LIDAR observations of the oil fog plume and airborne samples of SF/sub 6/ were collected. High altitude aerial photographs of daytime plumes were collected. Volume II lists the data in tabular form or cites the special supplemental reports by other participating contractors. While the primary user file and the data archive are maintained on 9 track/1600 cpi magnetic tapes, listings of the individual values are provided for the user who either cannot utilize the tapes or wishes to preview the data. The accuracies and quality of these data are described.

  9. 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.

  10. Measurements of vitamin B12 in human blood serum using resonance Raman spectroscopy

    Science.gov (United States)

    Tsiminis, G.; Schartner, E. P.; Brooks, J. L.; Hutchinson, M. R.

    2016-12-01

    Vitamin B12 (cobalamin and its derivatives) deficiency has been identified as a potential modifiable risk factor for dementia and Alzheimer's disease. Chronic deficiency of vitamin B12 has been significantly associated with an increased risk of cognitive decline. An effective and efficient method for measuring vitamin B12 concentration in human blood would enable ongoing tracking and assessment of this potential modifiable risk factor. In this work we present an optical sensor based on resonance Raman spectroscopy for rapid measurements of vitamin B12 in human blood serum. The measurement takes less than a minute and requires minimum preparation (centrifuging) of the collected blood samples.

  11. Special Properties of Coherence Scanning Interferometers for large Measurement Volumes

    Science.gov (United States)

    Bauer, W.

    2011-08-01

    In contrast to many other optical methods the uncertainty of Coherence Scanning Interferometer (CSI) in vertical direction is independent from the field of view. Therefore CSIs are ideal instruments for measuring 3D-profiles of larger areas (36×28mm2, e.g.) with high precision. This is of advantage for the determination of form parameters like flatness, parallelism and steps heights within a short time. In addition, using a telecentric beam path allows measurements of deep lying surfaces (automotive suppliers or from the steel industry.

  12. Phase-Contrast Magnetic Resonance Angiography Measurements of Global Cerebral Blood Flow in the Neonate

    NARCIS (Netherlands)

    Benders, Manon J. N. L.; Hendrikse, Jeroen; de Vries, Linda S.; van Bel, Frank; Groenendaal, Floris

    2011-01-01

    Cerebral blood flow (CBF) alterations are important in pathogenesis of neonatal ischemic/hemorrhagic brain damage. In clinical practice, estimation of neonatal CBF is mostly based on Doppler-measured blood flow velocities in major intracranial arteries. Using phase-contrast magnetic resonance angiog

  13. A SEMICONDUCTOR-LASER USED FOR DIRECT MEASUREMENT OF THE BLOOD PERFUSION OF TISSUE

    NARCIS (Netherlands)

    DEMUL, FFM; KOELINK, MH; WEIJERS, AL; GREVE, J; AARNOUDSE, JG; GRAAFF, R; DASSEL, ACM

    1993-01-01

    An instrument consisting merely of a semiconductor laser in its own housing was used to measure the blood perfusion in tissue. Use is made of the feedback of Doppler-scattered light to the photodiode in the laser housing. A recording perfusion of a finger under occlusion of blood flow in the arm is

  14. Lack of reproducibility of linkage results in serially measured blood pressure data

    NARCIS (Netherlands)

    Patel, [No Value; Celedon, JC; Weiss, ST; Palmer, LJ

    2003-01-01

    Background: Using the longitudinal Framingham Heart Study data on blood pressure, we analyzed the reproducibility of linkage measures from serial cross-sectional surveys of a defined population by performing genome-wide model-free linkage analyses to systolic blood pressure (SBP) and history of hype

  15. Measuring the volume of uterine fibroids using 2- and 3-dimensional ultrasound and comparison with histopathology.

    Science.gov (United States)

    Zivković, Nikica; Zivković, Kreiimir; Despot, Albert; Paić, Josip; Zelić, Ana

    2012-12-01

    The aim of this study was clinical testing of the reliability and usability of three-dimensional (3D) and two-dimensional (2D) ultrasound (US) technology. The ultimate aim and purpose of this study was to establish ultrasound methods, standards and protocols for determining the volume of any gynecologic organ or tumor. The study included 31 women in reproductive age and postmenopause. All patients were examined with a RIC 5-9 3D-endovaginal probe (4.3-7.5 MHz) on a Voluson 730 Pro ultrasound device. The volume of myomas was measured by using the existing 2D and 3D ultrasound methods on the above mentioned device. All patients underwent myomectomy or hysterectomy due to clinically and ultrasonographically diagnosed uterine myomas indicating operative intervention. After the operation, the pathologist determined the volume of removed myomas by measuring them in a gauge bowl containing water, i.e. using Archimedes' principle (lift), serving as the control group with histopathologic diagnosis. A total of 155 myoma volumes were processed on 2D display, 31 myoma volumes were preoperatively measured on 3D display and 31 myoma volumes were measured by the pathologist. The values of US measurements for each US method were expressed as mean value of all measurements of myoma volumes. Statistical processing of the results and Student's t-test for independent samples revealed that the 2nd examined US method (measuring of myoma by using an ellipse and the longer tumor diameter) and 4th examined US method (measuring of myoma by using the longer and shorter tumor diameters together with establishing their mean values) in 2D US technique, as well as the 6th examined US method in 3D US technique showed no significant measurement differences in comparison with control measurement in a gauge bowl containing water (p < 0.05), indicating acceptability of the US methods for verifying tumor volumes. The standard error in determining the volume of myomas by the above US methods varied

  16. Development of a Phantom Tissue for Blood Perfusion Measurements and Noninvasive Blood Perfusion Estimation in Living Tissue

    OpenAIRE

    Mudaliar, Ashvinikumar

    2007-01-01

    A convenient method for testing and calibrating surface perfusion sensors has been developed. A phantom tissue model is used to mimic the non-directional blood flow of tissue perfusion. A computational fluid dynamics (CFD) model was constructed in Fluent to design the phantom tissue and validate the experimental results. The phantom perfusion system was used with a perfusion sensor based on the clearance of thermal energy. A heat flux gage measures the heat flux response of tissue whe...

  17. Can a central blood volume deficit be detected by systolic pressure variation during spontaneous breathing?

    DEFF Research Database (Denmark)

    Dahl, Michael; Hayes, Chris Frederick; Steen Rasmussen, Bodil;

    2016-01-01

    BACKGROUND: Whether during spontaneous breathing arterial pressure variations (APV) can detect a volume deficit is not established. We hypothesized that amplification of intra-thoracic pressure oscillations by breathing through resistors would enhance APV to allow identification of a reduced card...

  18. Reference values for alveolar membrane diffusion capacity and pulmonary capillary blood volume

    NARCIS (Netherlands)

    Zanen, P; van der Lee, [No Value; van der Mark, T; van den Bosch, JMM

    2001-01-01

    The reference values for diffusion capacity of the alveolar capillary membrane (Tm,CO) and pulmonary capillary volume (Qc) are scarce, while the standard deviations of the equations are large. New equations and residual standard deviations (RSDs) were determined in a sample of healthy subjects. Tm,C

  19. Decreased blood platelet volume and count in patients with liver disease

    DEFF Research Database (Denmark)

    Jørgensen, B; Fischer, E; Ingeberg, S;

    1984-01-01

    Mean platelet volume (MPV) and count (PLT) were assessed in patients with moderately affected liver function. PLT was significantly decreased in patients with liver disease (197 X 10(9)l-1 +/- 87 (SD), no. = 79) compared with that of controls (273 X 10(9)l-1 +/- 53 (SD), no. = 37, P less than 0...

  20. Measurement of cerebral blood flow using phase contrast magnetic resonance imaging and duplex ultrasonography.

    Science.gov (United States)

    Khan, Muhammad Ayaz; Liu, Jie; Tarumi, Takashi; Lawley, Justin Stevan; Liu, Peiying; Zhu, David C; Lu, Hanzhang; Zhang, Rong

    2017-02-01

    Phase contrast magnetic resonance imaging (PC-MRI) and color-coded duplex ultrasonography (CDUS) are commonly used for measuring cerebral blood flow in the internal carotid (ICA) and vertebral arteries. However, agreement between the two methods has been controversial. Recent development of high spatial and temporal resolution blood vessel wall edge-detection and wall-tracking methods with CDUS increased the accuracy and reliability of blood vessel diameter, hence cerebral blood flow measurement. The aim of this study was to compare the improved CDUS method with 3 T PC-MRI for cerebral blood flow measurements. We found that cerebral blood flow velocity measured in the ICA was lower using PC-MRI than CDUS (left ICA: PC-MRI, 18.0 ± 4.2 vs. CDUS, 25.6 ± 8.6 cm/s; right ICA: PC-MRI, 18.5 ± 4.8 vs. CDUS, 26.6 ± 6.7 cm/s, both p blood flow velocity measured in the left vertebral artery with PC-MRI was also lower than CDUS, but no differences in vertebral artery diameter were observed between the methods. Dynamic changes and/or intrinsic physiological fluctuations may have caused these differences in vessel diameter and velocity measurements between the methods. However, estimation of volumetric cerebral blood flow was similar and correlated between the methods despite the presence of large individual differences. These findings support the use of CDUS for cerebral blood flow measurements in the ICA and vertebral artery.

  1. Special Properties of Coherence Scanning Interferometers for large Measurement Volumes

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, W, E-mail: W.bauer@polytec.de [Polytec GmbH, Polytec Platz 1-7, 76337 Waldbronn (Germany)

    2011-08-19

    In contrast to many other optical methods the uncertainty of Coherence Scanning Interferometer (CSI) in vertical direction is independent from the field of view. Therefore CSIs are ideal instruments for measuring 3D-profiles of larger areas (36x28mm{sup 2}, e.g.) with high precision. This is of advantage for the determination of form parameters like flatness, parallelism and steps heights within a short time. In addition, using a telecentric beam path allows measurements of deep lying surfaces (<70mm) and the determination of form parameters with large step-heights. The lateral and spatial resolution, however, are reduced. In this presentation different metrological characteristics together with their potential errors are analyzed for large-scale measuring CSIs. Therefore these instruments are ideal tools in quality control for good/bad selections, e.g. The consequences for the practical use in industry and for standardization are discussed by examples of workpieces of automotive suppliers or from the steel industry.

  2. Cerebral Blood Volume ASPECTS Is the Best Predictor of Clinical Outcome in Acute Ischemic Stroke: A Retrospective, Combined Semi-Quantitative and Quantitative Assessment.

    Directory of Open Access Journals (Sweden)

    Marina Padroni

    Full Text Available The capability of CT perfusion (CTP Alberta Stroke Program Early CT Score (ASPECTS to predict outcome and identify ischemia severity in acute ischemic stroke (AIS patients is still questioned.62 patients with AIS were imaged within 8 hours of symptom onset by non-contrast CT, CT angiography and CTP scans at admission and 24 hours. CTP ASPECTS was calculated on the affected hemisphere using cerebral blood flow (CBF, cerebral blood volume (CBV and mean transit time (MTT maps by subtracting 1 point for any abnormalities visually detected or measured within multiple cortical circular regions of interest according to previously established thresholds. MTT-CBV ASPECTS was considered as CTP ASPECTS mismatch. Hemorrhagic transformation (HT, recanalization status and reperfusion grade at 24 hours, final infarct volume at 7 days and modified Rankin scale (mRS at 3 months after onset were recorded.Semi-quantitative and quantitative CTP ASPECTS were highly correlated (p<0.00001. CBF, CBV and MTT ASPECTS were higher in patients with no HT and mRS ≤ 2 and inversely associated with final infarct volume and mRS (p values: from p<0.05 to p<0.00001. CTP ASPECTS mismatch was slightly associated with radiological and clinical outcomes (p values: from p<0.05 to p<0.02 only if evaluated quantitatively. A CBV ASPECTS of 9 was the optimal semi-quantitative value for predicting outcome.Our findings suggest that visual inspection of CTP ASPECTS recognizes infarct and ischemic absolute values. Semi-quantitative CBV ASPECTS, but not CTP ASPECTS mismatch, represents a strong prognostic indicator, implying that core extent is the main determinant of outcome, irrespective of penumbra size.

  3. Measurement of temperature decrease caused by blood flow in focused ultrasound irradiation by thermal imaging method

    Science.gov (United States)

    Tsuchiya, Takenobu; Hatano, Yuichi; Mori, Yashunori; Shen, Rakushin; Endoh, Nobuyuki

    2016-07-01

    In this study, to estimate the local temperature changes caused by a thick blood vessel, the temperature distribution in a tissue phantom with a thick blood vessel during focused ultrasound irradiation was measured by a thermal imaging method. The blood flow rate in the simulated blood vessel was varied and the relationship between flow rate and temperature decrease was examined. The phantom using the thermal imaging method is divided into two parts, and the increases in temperature distribution as a function of blood flow rate are measured using a thermocamera under constant ultrasound irradiation. The irradiation conditions of ultrasound waves were a central frequency of 1 MHz, a wave number length of 200 cycles, and a duty ratio of 0.2. The irradiation duration was 5 min, and the ultrasound intensity I SPTA was 36 W/cm2. The amount of temperature decrease caused by the cooling effect of blood flow increased with the blood flow rate and it became constant at a certain threshold of blood flow rate. The threshold of blood flow rate is about 250 ml/min.

  4. Mucosal blood flow measurements using laser Doppler perfusion monitoring

    Institute of Scientific and Technical Information of China (English)

    Dag Arne Lihaug Hoff; Hans Gregersen; Jan Gunnar Hatlebakk

    2009-01-01

    Perfusion of individual tissues is a basic physiological process that is necessary to sustain oxygenation and nutrition at a cellular level. Ischemia, or the insufficiency of perfusion, is a common mechanism for tissue death or degeneration, and at a lower threshold, a mechanism for the generation of sensory signalling including pain. It is of considerable interest to study perfusion of peripheral abdominal tissues in a variety of circumstances. Microvascular disease of the abdominal organs has been implicated in the pathogenesis of a variety of disorders, including peptic ulcer disease, inflammatory bowel disease and chest pain. The basic principle of laser Doppler perfusion monitoring (LDPM) is to analyze changes in the spectrum of light reflected from tissues as a response to a beam of monochromatic laser light emitted. It reflects the total local microcirculatory blood perfusion, including perfusion in capillaries, arterioles, venules and shunts. During the last 20-25 years, numerous studies have been performed in different parts of the gastrointestinal (GI) tract using LDPM. In recent years we have developed a multi-modal catheter device which includes a laser Doppler probe, with the intent primarily to investigate patients suffering from functional chest pain of presumed oesophageal origin. Preliminary studies show the feasibility of incorporating LDPM into such catheters for performing physiological studies in the GI tract. LDPM has emerged as a research and clinical tool in preference to other methods; but, it is important to be aware of its limitations and account for them when reporting results.

  5. Doctor Reports New Way to Measure Blood Sugar

    Institute of Scientific and Technical Information of China (English)

    林徽英

    2000-01-01

    对“糖尿病”及其危害,本文有一简略说明: Diabetes occurs when blood sugar,or glucose,a source of body fuel,is toohigh and the body is not able to burn it.The disease can lead to blindness,organdiseases,stroke and death. 句中的一个动词burn令我们过目难忘。此外,此疾引起的后果也令人生畏:blindness,organ diseases,stroke and death. 要测得患者的血糖含量,就得验血,就得像本文所讲的那样“pricking(刺;戳)the skin and drawing a tiny amount of blood”。 美国宾夕法尼亚州立大学的研究人员研制了a hand—held ultrasound(超声波)machine,验血者可免受皮肉之苦,而又可测量到准确的血糖含量。 文章末尾有一条信息:美国人中糖尿病患者约占总人口的6%。

  6. Ghost Cell Suspensions as Blood Analogue Fluid for Macroscopic Particle Image Velocimetry Measurements.

    Science.gov (United States)

    Jansen, Sebastian V; Müller, Indra; Nachtsheim, Max; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2016-02-01

    Spatially resolved measurement of blood flow is of great interest in the development of artificial blood-carrying devices such as blood pumps, heart valve prostheses, and oxygenators. Particle image velocimetry (PIV) is able to measure instantaneous velocity fields in a plane with high accuracy and is being used more frequently for the development of such devices. However, as this measurement technique is based on optical access, blood flow at physiological hematocrit values is difficult to measure due to its low transparency and multiscattering properties. So far, only very small dimensions (in the range of 400 μm) can be measured using PIV. A suspension of ghost cells (GCs) offers a higher optical transparency than blood while having a similar rheological behavior. In this study, a procedure for the production of GC suspensions containing a very low intracellular hemoglobin concentration is presented. With the help of multiple rounds of controlled cell lysis, the intracellular hemoglobin concentration could be decreased to a point where a standard macroscopic PIV measurement was possible. A velocity profile of a 44% GC suspension in a circular channel with a diameter of 9.5 mm was measured with high spatial resolution. Meanwhile, the rheological behavior was found to be comparable with blood.

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

    Science.gov (United States)

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

    2012-11-01

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

  8. Standing orthostatic blood pressure measurements cannot be replaced by sitting measurements.

    Science.gov (United States)

    Breeuwsma, Anna C; Hartog, Laura C; Kamper, Adriaan M; Groenier, Klaas H; Bilo, Henk Jg; Kleefstra, Nanne; Van Hateren, Kornelis Jj

    2017-03-16

    As many elderly patients are not able to stand for several minutes, sitting orthostatic blood pressure (BP) measurements are sometimes used as an alternative. We aimed to investigate the difference in BP response and orthostatic hypotension (OH) prevalence between the standard postural change to the sitting and the standing position in a cross-sectional observational study. BP was measured with a continuous BP measurement device during two postural changes, from supine to the sitting and from supine to the standing position. Linear mixed models were used to investigate the differences in changes (Δ) of systolic BP (SBP) and diastolic BP (DBP) between the two postural changes. The prevalence and the positive and negative proportions of agreement of OH were calculated of the two postural changes. One hundred and four patients with a mean age of 69 years were included. ΔSBP was significantly larger in the standing position compared with the sitting between 0 and 44 s. ΔDBP was significantly larger in the sitting position compared with the standing 75-224 s after postural change. The prevalence of OH was 66.3% (95% confidence interval (CI) 57.2, 75.4) in the standing position and 67.3% (95% CI 58.3, 76.3) in the sitting position. The positive proportion of agreement was 74.8% and the negative proportion of agreement was 49.3%. A clear difference was seen in BP response between the two postural changes. Although no significant difference in prevalence of OH was observed, the positive and negative proportion of agreement of the prevalence of OH were poor to moderate, which indicates a different outcome between both postural changes.Hypertension Research advance online publication, 16 March 2017; doi:10.1038/hr.2017.39.

  9. Application of transcutaneous diffuse reflectance spectroscopy in the measurement of blood glucose concentration

    Institute of Scientific and Technical Information of China (English)

    Wenliang Chen(陈文亮); Rong Liu(刘蓉); Houxin Cui(崔厚欣); Kexin Xu(徐可欣); Lina Lü(吕丽娜)

    2004-01-01

    In this paper, the propagation characteristics of near-infrared (NIR) light in the palm tissue are analyzed,and the principle and feasibility of using transcutaneous diffuse reflectance spectroscopy for non-invasive blood glucose detection are presented. An optical probe suitable for measuring the diffuse reflectance spectrum of human palm and a non-invasive blood glucose detection system using NIR spectroscopy are designed. Based on this system, oral glucose tolerance tests are performed to measure the blood glucose concentrations of two young healthy volunteers. The partial least square calibration model is then constructed by all individual experimental data. The final result shows that correlation coefficients of the two experiments between the predicted blood glucose concentrations and the reference blood glucose concentrations are 0.9870 and 0.9854, respectively. The root mean square errors of prediction of full cross validation are 0.54 and 0.52 mmol/1, respectively.

  10. Comparison of aerosol volume size distributions between column and surface measurements downwind of Seoul, Korea

    Science.gov (United States)

    Park, J. S.; Choi, Y.; Ghim, Y. S.

    2015-12-01

    The aerosol volume size distribution is one of the most important parameters in retrieving aerosol optical properties and studying radiative forcing. The column-integrated aerosol volume size distribution for AERONET was obtained from inversion product level 1.5 (22 bins between 0.1 and 30 μm in diameter) from the measurements of CIMEL sunphotometer (CE-318); that for SKYNET was obtained using skyrad.pack V5 (20 bins, 0.02-33 μm) from the measurements of PREDE skyradiometer (POM-02). The aerosol volume size distribution at the surface was measured using a wide range aerosol spectrometer system consisting of a scanning mobility particle scanner (Grimm, Model 5.419; 89 bins, 0.005-0.35 μm) and an optical particle counter (Grimm, Model 1.109; 31 bins, 0.27-34 μm). The measurement was conducted in Yongin, downwind of Seoul, Korea, from April 30 to June 27, 2015. The measurement site is located on the rooftop of a five-story building on the hill (37.34°N, 127.27°E, 167 m above sea level) in the global campus of Hankuk University of Foreign Studies. To investigate the discrepancy in effective diameter and fine mode volume fraction, we compared the volume size distributions when the measurement time coincided within 5 minutes because the measurement intervals were different between instruments.

  11. Simple Radiowave-Based Method For Measuring Peripheral Blood Flow Project

    Science.gov (United States)

    Oliva-Buisson, Yvette J.

    2014-01-01

    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 and middle cerebral artery. The result will be the technological capability to measure peripheral blood flow rates and flow changes during various environmental stressors such as microgravity without contact to the individual being monitored. This technology may also lead to an easier method of detecting venous gas emboli during extravehicular activities.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  13. Validity of blood flow measurement using 320 multi-detectors CT and first-pass distribution theory: a phantom study

    Science.gov (United States)

    Chen, Jun; Yu, Xuefang; Xu, Shaopeng; Zhou, Kenneth J.

    2015-03-01

    To evaluate the feasibility of measuring the myocardial blood flow using 320 row detector CT by first-pass technique. Heart was simulated with a container that was filled with pipeline of 3mm diameter; coronary artery was simulated with a pipeline of 2 cm diameter and connected with the simulated heart. The simulated coronary artery was connected with a big container with 1500 ml saline and 150ml contrast agent. One pump linking with simulated heart will withdraw with a speed of 10 ml/min, 15 ml/min, 20 ml/min, 25 ml/min and 30 ml/min. First CT scan starts after 30 s of pumpback with certain speed. The second CT scan starts 5 s after first CT scans. CT images processed as follows: The second CT scan images subtract first CT scan images, calculate the increase of CT value of simulated heart and the CT value of the unit volume of simulated coronary artery and then to calculate the total inflow of myocardial blood flow. CT myocardial blood flows were calculated as: 0.94 ml/s, 2.09 ml/s, 2.74 ml/s, 4.18 ml/s, 4.86 ml/s. The correlation coefficient is 0.994 and r2 = 0.97. The method of measuring the myocardial blood flow using 320 row detector CT by 2 scans is feasible. It is possible to develop a new method for quantitatively and functional assessment of myocardial perfusion blood flow with less radiation does.

  14. A new method for the measurement of meteorite bulk volume via ideal gas pycnometry

    Science.gov (United States)

    Li, Shijie; Wang, Shijie; Li, Xiongyao; Li, Yang; Liu, Shen; Coulson, Ian M.

    2012-10-01

    To date, of the many techniques used to measure the bulk volume of meteorites, only three methods (Archimedean bead method, 3-D laser imaging and X-ray microtomography) can be considered as nondestructive or noncontaminating. The bead method can show large, random errors for sample sizes of smaller than 5 cm3. In contrast, 3-D laser imaging is a high-accuracy method even when measuring the bulk volumes of small meteorites. This method is both costly and time consuming, however, and meteorites of a certain shape may lead to some uncertainties in the analysis. The method of X-ray microtomography suffers from the same problems as 3-D laser imaging. This study outlines a new method of high-accuracy, nondestructive and noncontaminating measurement of the bulk volume of meteorite samples. In order to measure the bulk volume of a meteorite, one must measure the total volume of the balloon vacuum packaged meteorite and the volume of balloon that had been used to enclose the meteorite using ideal gas pycnometry. The difference between the two determined volumes is the bulk volume of the meteorite. Through the measurement of zero porosity metal spheres and tempered glass fragments, our results indicate that for a sample which has a volume of between 0.5 and 2 cm3, the relative error of the measurement is less than ±0.6%. Furthermore, this error will be even smaller (less than ±0.1%) if the determined sample size is larger than 2 cm3. The precision of this method shows some volume dependence. For samples smaller than 1 cm3, the standard deviations are less than ±0.328%, and these values will fall to less than ±0.052% for samples larger than 2 cm3. The porosities of nine fragments of Jilin, GaoGuenie, Zaoyang and Zhaodong meteorites have been measured using our vacuum packaging-pycnometry method, with determined average porosities of Jilin, GaoGuenie, Zaoyang and Zhaodong of 9.0307%, 2.9277%, 17.5437% and 5.9748%, respectively. These values agree well with the porosities

  15. Blood Volume: Importance and Adaptations to Exercise Training, Environmental Stresses and Trauma Sickness

    Science.gov (United States)

    2000-02-01

    the elevation of Hb concentration (from plasma loss) is the most important factor contributing to the performance improve- ment by facilitating O2...A., P. J. BROCK, L. C. KEIL, E. M. BERNAUER, and J. E. GREENLEAF. Exercise training-induced hypervolemia: role of plasma albumin, renin , and...mechanism of hypervol- emia. J. Appl. Physiol. 48:657–664, 1980. 27. CONVERTINO, V. A., L. C. KEIL, and J. E. GREENLEAF. Plasma volume, renin , and

  16. Accurate monitoring of intravascular fluid volume: A novel application of intrathoracic impedance measures for the guidance of volume reduction therapy

    Directory of Open Access Journals (Sweden)

    Barbara A. Lara

    2015-09-01

    Conclusion: Impedance vectors derived from a multivector monitoring system reflect changes in intravascular plasma volume. Two of these vectors most closely track changes in plasma volume and may be used to more accurately guide and optimize volume reduction therapy.

  17. Model estimation of cerebral hemodynamics between blood flow and volume changes: a data-based modeling approach.

    Science.gov (United States)

    Wei, Hua-Liang; Zheng, Ying; Pan, Yi; Coca, Daniel; Li, Liang-Min; Mayhew, J E W; Billings, Stephen A

    2009-06-01

    It is well known that there is a dynamic relationship between cerebral blood flow (CBF) and cerebral blood volume (CBV). With increasing applications of functional MRI, where the blood oxygen-level-dependent signals are recorded, the understanding and accurate modeling of the hemodynamic relationship between CBF and CBV becomes increasingly important. This study presents an empirical and data-based modeling framework for model identification from CBF and CBV experimental data. It is shown that the relationship between the changes in CBF and CBV can be described using a parsimonious autoregressive with exogenous input model structure. It is observed that neither the ordinary least-squares (LS) method nor the classical total least-squares (TLS) method can produce accurate estimates from the original noisy CBF and CBV data. A regularized total least-squares (RTLS) method is thus introduced and extended to solve such an error-in-the-variables problem. Quantitative results show that the RTLS method works very well on the noisy CBF and CBV data. Finally, a combination of RTLS with a filtering method can lead to a parsimonious but very effective model that can characterize the relationship between the changes in CBF and CBV.

  18. Inter-observer variation in ultrasound measurement of the volume and diameter of thyroid nodules

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Jun; Baek, Jung Hwan; Hong, Min Ji; Lee, Jeong Hyun [Dept. of Radiology, and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2015-06-15

    Thyroid nodule measurement using ultrasonography (US) is widely performed in various clinical scenarios. The purpose of this study was to evaluate inter-observer variation in US measurement of the volume and maximum diameter of thyroid nodules. This retrospective study included 73 consecutive patients with 85 well-defined thyroid nodules greater than 1 cm in their maximum diameter. US examinations were independently performed by using standardized measurement methods, conducted by two clinically experienced thyroid radiologists. The maximum nodule diameter and nodule volume, calculated from nodule diameters using the ellipsoid formula, were obtained by each reader. Inter-observer variations in volume and maximum diameter were determined using 95% Bland-Altman limits of agreement. The degree of inter-observer variations in volumes and the maximum diameters were compared using the Student's t test, between nodules < 2 cm in maximum diameter and those with > or = 2 cm. The mean inter-observer difference in measuring the nodule volume was -1.6%, in terms of percentage of the nodule volume, and the 95% limit of agreement was +/- 13.1%. For maximum nodule diameter, the mean inter-observer difference was -0.6%, in terms of percentage of the nodule diameter, and the 95% limit of agreement was +/- 7.3%. Inter-observer variation in volume was greater in nodules of < 2 cm in maximum diameter, compared to the larger nodules (p = 0.035). However, no statistically significant difference was noted between the two groups regarding maximum nodule diameters (p = 0.511). Any differences smaller than 13.1% and 7.3% in volume and maximum diameter, respectively, measured by using US for well-defined thyroid nodules of > 1 cm should not be considered as a real change in size.

  19. Measurement of volatile organic compounds in human blood.

    OpenAIRE

    Ashley, D L; Bonin, M A; Cardinali, F L; McCraw, J. M.; Wooten, J V

    1996-01-01

    Volatile organic compounds (VOCs) are an important public health problem throughout the developed world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. The analytical methodology chosen to measure toxicants in biological materials must be well validated and carefully carried out; poor quality assurance can lead to invalid resul...

  20. Determination of air-loop volume and radon partition coefficient for measuring radon in water sample.

    Science.gov (United States)

    Lee, Kil Yong; Burnett, William C

    A simple method for the direct determination of the air-loop volume in a RAD7 system as well as the radon partition coefficient was developed allowing for an accurate measurement of the radon activity in any type of water. The air-loop volume may be measured directly using an external radon source and an empty bottle with a precisely measured volume. The partition coefficient and activity of radon in the water sample may then be determined via the RAD7 using the determined air-loop volume. Activity ratios instead of absolute activities were used to measure the air-loop volume and the radon partition coefficient. In order to verify this approach, we measured the radon partition coefficient in deionized water in the temperature range of 10-30 °C and compared the values to those calculated from the well-known Weigel equation. The results were within 5 % variance throughout the temperature range. We also applied the approach for measurement of the radon partition coefficient in synthetic saline water (0-75 ppt salinity) as well as tap water. The radon activity of the tap water sample was determined by this method as well as the standard RAD-H2O and BigBottle RAD-H2O. The results have shown good agreement between this method and the standard methods.

  1. Measurement of myocardial blood flow with oxygen-15 labelled water: comparison of different administration protocols.

    Science.gov (United States)

    Hermansen, F; Rosen, S D; Fath-Ordoubadi, F; Kooner, J S; Clark, J C; Camici, P G; Lammertsma, A A

    1998-07-01

    Positron emission tomography (PET) in conjunction with C15O2 or H215O can be used to measure myocardial blood flow (MBF) and tissue fraction (TF), i.e. the fraction of the tissue mass in the volume of the region of interest. However, with C15O2 inhalation, the tissue fraction in the septum is overestimated. Bolus injection of H215O together with arterial cannulation gives very precise results but is invasive. The purpose of this study was to develop a method which circumvents these problems. A four-parameter model with parameters for MBF, TF and spill-over fractions from both left and right ventricular cavities was developed. This method was compared with a three-parameter model (no right ventricular cavity spill-over) in both septal and non-septal regions of interest for three different administration protocols: bolus injection of H215O, infusion of H215O and inhalation of C15O2. It was found that MBF can be measured with intravenous administration of H215O without the requirement for arterial cannulation. The four-parameter protocol with bolus injection was stable in clinical studies. The four-parameter model proved essential for the septum, where it gave highly significantly better fits than did the three-parameter model (P<0.00003 in each of 15 subjects). Administration of H215O together with this four-parameter model also circumvented the problem of overestimation of TF in the septum seen with C15O2 inhalation. In addition, the radiation dose of H215O protocols is lower than that of C15O2 inhalation. Using a left atrial input curve instead of a left ventricular cavity input curve gave the same mean MBF and TF.

  2. Estimating mechanical blood trauma in a centrifugal blood pump: laser Doppler anemometer measurements of the mean velocity field.

    Science.gov (United States)

    Pinotti, M; Paone, N

    1996-06-01

    A laser Doppler anemometer (LDA) was used to obtain the mean velocity and the Reynolds stress fields in the inner channels of a well-known centrifugal vaneless pump (Bio-pump). Effects of the excessive flow resistance against which an occlusive pump operates in some surgical situations, such as cardiopulmonary bypass, are illustrated. The velocity vector field obtained from LDA measurements reveals that the constraint-forced vortex provides pumping action in a restricted area in the core of the pump. In such situations, recirculating zones dominate the flow and consequently increase the damage to blood cells and raise the risk of thrombus formation in the device. Reynolds normal and shear stress fields were obtained in the entry flow for the channel formed by two rotating cones to illustrate the effects of flow disturbances on the potential for blood cell damage.

  3. Blood Contamination in Saliva: Impact on the Measurement of Salivary Oxidative Stress Markers

    Directory of Open Access Journals (Sweden)

    Natália Kamodyová

    2015-01-01

    Full Text Available Salivary oxidative stress markers represent a promising tool for monitoring of oral diseases. Saliva can often be contaminated by blood, especially in patients with periodontitis. The aim of our study was to examine the impact of blood contamination on the measurement of salivary oxidative stress markers. Saliva samples were collected from 10 healthy volunteers and were artificially contaminated with blood (final concentration 0.001–10%. Next, saliva was collected from 12 gingivitis and 10 control patients before and after dental hygiene treatment. Markers of oxidative stress were measured in all collected saliva samples. Advanced oxidation protein products (AOPP, advanced glycation end products (AGEs, and antioxidant status were changed in 1% blood-contaminated saliva. Salivary AOPP were increased in control and patients after dental treatment (by 45.7% and 34.1%, p<0.01. Salivary AGEs were decreased in patients after microinjury (by 69.3%, p<0.001. Salivary antioxidant status markers were decreased in both control and patients after dental treatment (p<0.05 and p<0.01. One % blood contamination biased concentrations of salivary oxidative stress markers. Saliva samples with 1% blood contamination are visibly discolored and can be excluded from analyses without any specific biochemic detection of blood constituents. Salivary markers of oxidative stress were significantly altered in blood-contaminated saliva in control and patients with gingivitis after dental hygiene treatment.

  4. LARGE VOLUME IONIZATION CHAMBER USED AS LABORATORY REFERENCE FOR LOW ENERGY X—RAY MEASUREMENT

    Institute of Scientific and Technical Information of China (English)

    杨国山; 薛永库; 等

    1994-01-01

    A large volume spherical ionization chamber of 195mm diameter and 0.36mg/cm2 wall thickness made from conducting carbon-fibre epoxy composite material has been developed.The mechanical intensity of the chamber is satisfactory for a good longterm volume stability.Owing to its large volume and thin wall,the chamber is sensitive to low energy photon beams and has excellent energy-response characteristics.This ionization chamber is suitable not only for a laboratory reference but also for measurement of low energy photon beam exposure rates at protection-level.

  5. Accuracy of cancellous bone volume fraction measured by micro-CT scanning

    DEFF Research Database (Denmark)

    Ding, Ming; Odgaard, A; Hvid, I

    1999-01-01

    Volume fraction, the single most important parameter in describing trabecular microstructure, can easily be calculated from three-dimensional reconstructions of micro-CT images. This study sought to quantify the accuracy of this measurement. One hundred and sixty human cancellous bone specimens...... which covered a large range of volume fraction (9.8-39.8%) were produced. The specimens were micro-CT scanned, and the volume fraction based on Archimedes' principle was determined as a reference. After scanning, all micro-CT data were segmented using individual thresholds determined by the scanner...

  6. Simultaneous blood flow and blood oxygenation measurements using a combination of diffuse speckle contrast analysis and near-infrared spectroscopy

    Science.gov (United States)

    Seong, Myeongsu; Phillips, Zephaniah; Mai, Phuong Minh; Yeo, Chaebeom; Song, Cheol; Lee, Kijoon; Kim, Jae Gwan

    2016-02-01

    A combined diffuse speckle contrast analysis (DSCA)-near-infrared spectroscopy (NIRS) system is proposed to simultaneously measure qualitative blood flow and blood oxygenation changes in human tissue. The system employs an optical switch to alternate two laser sources at two different wavelengths and a CCD camera to capture the speckle image. Therefore, an optical density can be measured from two wavelengths for NIRS measurements and a speckle contrast can be calculated for DSCA measurements. In order to validate the system, a flow phantom test and an arm occlusion protocol for arterial and venous occlusion were performed. Shorter exposure times (<1 ms) show a higher drop (between 50% and 66%) and recovery of 1/KS2 values after occlusion (approximately 150%), but longer exposure time (3 ms) shows more consistent hemodynamic changes. For four subjects, the 1/KS2 values dropped to an average of 82.1±4.0% during the occlusion period and the average recovery of 1/KS2 values after occlusion was 109.1±0.8%. There was also an approximately equivalent amplitude change in oxyhemoglobin (OHb) and deoxyhemoglobin (RHb) during arterial occlusion (max RHb=0.0085±0.0024 mM/DPF, min OHb=-0.0057±0.0044 mM/DPF). The sensitivity of the system makes it a suitable modality to observe qualitative hemodynamic trends during induced physiological changes.

  7. Volume measurement by using super-resolution MRI: application to prostate volumetry

    CERN Document Server

    Oubel, Estanislao; Iannessi, Antoine

    2015-01-01

    Accuracy and precision of measurements are important for patient follow up in oncology but, unfortunately, partial volume effects introduce an undesired variability between observers. Super resolution techniques (SR) combine multiple acquisitions of an object into a single image richer in details. Herein, the use of SR for reducing variability is investigated in the specific context of prostate measurements. Prostate is typically imaged by T2-weighted MRI in three perpendicular low resolution images, each of them presenting partial volume effects in the direction of the slice selection gradient. SR techniques allow to combine these images into an image presenting the same level of details in all directions. This is expected to increase the accuracy and reproducibility of volume measurements, which in turn improves other derived measurements like PSA density.

  8. Color structured light system of chest wall motion measurement for respiratory volume evaluation.

    Science.gov (United States)

    Chen, Huijun; Cheng, Yuan; Liu, Dongdong; Zhang, Xiaodong; Zhang, Jue; Que, Chengli; Wang, Guangfa; Fang, Jing

    2010-01-01

    We present a structured light system to dynamically measure human chest wall motion for respiratory volume estimation. Based on a projection of an encoded color pattern and a few active markers attached to the trunk, respiratory volumes are obtained by evaluating the 3-D topographic changes of the chest wall in an anatomically consistent measuring region during respiration. Three measuring setups are established: a single-sided illuminating-recording setup for standing posture, an inclined single-sided setup for supine posture, and a double-sided setup for standing posture. Results are compared with the pneumotachography and show good agreement in volume estimations [correlation coefficient: R>0.99 (Pevaluation with high accuracy, but also regional pulmonary function assessment in different chest wall behaviors, with the advantage of whole-field measurement.

  9. Novel measurement of blood velocity profile using translating-stage optical method and theoretical modeling based on non-Newtonian viscosity model

    Science.gov (United States)

    Kim, Chang-Beom; Lim, Jaeho; Hong, Hyobong; Kresh, J. Yasha; Wootton, David M.

    2015-07-01

    Detailed knowledge of the blood velocity distribution over the cross-sectional area of a microvessel is important for several reasons: (1) Information about the flow field velocity gradients can suggest an adequate description of blood flow. (2) Transport of blood components is determined by the velocity profiles and the concentration of the cells over the cross-sectional area. (3) The velocity profile is required to investigate volume flow rate as well as wall shear rate and shear stress which are important parameters in describing the interaction between blood cells and the vessel wall. The present study shows the accurate measurement of non-Newtonian blood velocity profiles at different shear rates in a microchannel using a novel translating-stage optical method. Newtonian fluid velocity profile has been well known to be a parabola, but blood is a non-Newtonian fluid which has a plug flow region at the centerline due to yield shear stress and has different viscosities depending on shear rates. The experimental results were compared at the same flow conditions with the theoretical flow equations derived from Casson non-Newtonian viscosity model in a rectangular capillary tube. And accurate wall shear rate and shear stress were estimated for different flow rates based on these velocity profiles. Also the velocity profiles were modeled and compared with parabolic profiles, concluding that the wall shear rates were at least 1.46-3.94 times higher than parabolic distribution for the same volume flow rate.

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

    Science.gov (United States)

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

    2014-05-01

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

  11. Measuring air layer volumes retained by submerged floating-ferns Salvinia and biomimetic superhydrophobic surfaces

    Directory of Open Access Journals (Sweden)

    Matthias J. Mayser

    2014-06-01

    Full Text Available Some plants and animals feature superhydrophobic surfaces capable of retaining a layer of air when submerged under water. Long-term air retaining surfaces (Salvinia-effect are of high interest for biomimetic applications like drag reduction in ship coatings of up to 30%. Here we present a novel method for measuring air volumes and air loss under water. We recorded the buoyancy force of the air layer on leaf surfaces of four different Salvinia species and on one biomimetic surface using a highly sensitive custom made strain gauge force transducer setup. The volume of air held by a surface was quantified by comparing the buoyancy force of the specimen with and then without an air layer. Air volumes retained by the Salvinia-surfaces ranged between 0.15 and 1 L/m2 depending on differences in surface architecture. We verified the precision of the method by comparing the measured air volumes with theoretical volume calculations and could find a good agreement between both values. In this context we present techniques to calculate air volumes on surfaces with complex microstructures. The introduced method also allows to measure decrease or increase of air layers with high accuracy in real-time to understand dynamic processes.

  12. Three-dimensional measurement of bubble volume based on dual perspective imaging

    Science.gov (United States)

    Xue, Ting; Zhang, Shao-jie; Wu, Bin

    2017-01-01

    This paper presents a new three-dimensional (3D) volume measurement approach of bubble in gas-liquid two-phase flow. According to the dual perspective imaging principle, bubble feature images can be captured from two different view angles. The least square ellipse fitting algorithm is used to figure out the feature parameters from the captured images. Then the 3D volume of bubble can be quantitatively measured. Compaerd with the traditional volume estimation methods based on single perspective imaging, it can effectively reduce the loss of bubble feature information. In the experiment, the 3D volume reconstruction of bubbles from dual perspective images is conducted, and the variation of bubble volume in the bubble rising process is studied. The results show that the measurement accuracy based on the proposed 3D method is higher than those based on traditional methods. The volume of rising bubble is periodically changed, which indicates that bubble achieves periodic rotation and deformation in the rising process.

  13. Validity and repeatability of a depth camera-based surface imaging system for thigh volume measurement.

    Science.gov (United States)

    Bullas, Alice M; Choppin, Simon; Heller, Ben; Wheat, Jon

    2016-10-01

    Complex anthropometrics such as area and volume, can identify changes in body size and shape that are not detectable with traditional anthropometrics of lengths, breadths, skinfolds and girths. However, taking these complex with manual techniques (tape measurement and water displacement) is often unsuitable. Three-dimensional (3D) surface imaging systems are quick and accurate alternatives to manual techniques but their use is restricted by cost, complexity and limited access. We have developed a novel low-cost, accessible and portable 3D surface imaging system based on consumer depth cameras. The aim of this study was to determine the validity and repeatability of the system in the measurement of thigh volume. The thigh volumes of 36 participants were measured with the depth camera system and a high precision commercially available 3D surface imaging system (3dMD). The depth camera system used within this study is highly repeatable (technical error of measurement (TEM) of <1.0% intra-calibration and ~2.0% inter-calibration) but systematically overestimates (~6%) thigh volume when compared to the 3dMD system. This suggests poor agreement yet a close relationship, which once corrected can yield a usable thigh volume measurement.

  14. Spatial Visualization Tasks To Support Students’ Spatial Structuring In Learning Volume Measurement

    Directory of Open Access Journals (Sweden)

    Shintia Revina

    2011-07-01

    Full Text Available Many prior researches found that most of students in grade five tended to have difficulty in fully grasping the concept of volume measurement because they have to build their competence in spatial structuring. The unit of volume “packing” measurement must be integrated and coordinated in three-dimension. On the other hand, it is revealed the errors that students made on the volume measurement tasks with threedimensional cube arrays are related to some aspects of spatial visualization, such as the skill to "read off" two-dimensional representation of solid objects. For those reasons, this research is aimed to develop classroom activities with the use of spatial visualization tasks to support students’ spatial structuring in learning volume measurement. Consequently, design research was chosen as an appropriate means to achieve this research goal. In this research, a sequence of instructional activities is designed and developed based on the hypothesis of students’ learning processes. This research was conducted in grade 5 of SD Pupuk Sriwijaya Palembang, Indonesia.Keywords: volume measurement, spatial structuring, spatial visualization, design research. DOI: http://dx.doi.org/10.22342/jme.2.2.745.127-146

  15. Dynamic contrast-enhanced MRI assessment of hyperemic fractional microvascular blood plasma volume in peripheral arterial disease: initial findings.

    Directory of Open Access Journals (Sweden)

    Bas Versluis

    Full Text Available OBJECTIVES: The aim of the current study was to describe a method that assesses the hyperemic microvascular blood plasma volume of the calf musculature. The reversibly albumin binding contrast agent gadofosveset was used in dynamic contrast-enhanced magnetic resonance imaging (DCE MRI to assess the microvascular status in patients with peripheral arterial disease (PAD and healthy controls. In addition, the reproducibility of this method in healthy controls was determined. MATERIALS AND METHODS: Ten PAD patients with intermittent claudication and 10 healthy control subjects were included. Patients underwent contrast-enhanced MR angiography of the peripheral arteries, followed by one DCE MRI examination of the musculature of the calf. Healthy control subjects were examined twice on different days to determine normative values and the interreader and interscan reproducibility of the technique. The MRI protocol comprised dynamic imaging of contrast agent wash-in under reactive hyperemia conditions of the calf musculature. Using pharmacokinetic modeling the hyperemic fractional microvascular blood plasma volume (V(p, unit: % of the anterior tibial, gastrocnemius and soleus muscles was calculated. RESULTS: V(p was significantly lower for all muscle groups in PAD patients (4.3±1.6%, 5.0±3.3% and 6.1±3.6% for anterior tibial, gastrocnemius and soleus muscles, respectively compared to healthy control subjects (9.1±2.0%, 8.9±1.9% and 9.3±2.1%. Differences in V(p between muscle groups were not significant. The coefficient of variation of V(p varied from 10-14% and 11-16% at interscan and interreader level, respectively. CONCLUSIONS: Using DCE MRI after contrast-enhanced MR angiography with gadofosveset enables reproducible assessment of hyperemic fractional microvascular blood plasma volume of the calf musculature. V(p was lower in PAD patients than in healthy controls, which reflects a promising functional (hemodynamic biomarker for the

  16. Location studies of prostate volume measurement by using transrectal ultrasonography: Experimental study by self-produced prostate phantom

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Joon; Byeon, Il Kyun; Lee, Hoo Min [Dept. of Radiological Science, (Korea, Republic of); Kim, Yun Min; Kim, Hyeong Gyun [Dept. of Radiological Technology, Dongnam Health University, Suwon (Korea, Republic of)

    2015-12-15

    Accurate volume measurement of the prostate is a significant role in determining the result of diagnosis and treatment of benign prostate hyperplasia. The purpose of this study was to determine, when measuring prostate volume by TRUS, whether location is more accurately determined by transaxial or longitudinal scanning. With reference to the patient’s image, it was produced six prostate model. It compares the actual volume and the measurement volume, and find the optimal measurement position of each specific model. Prostate volume measured by TRUS closely correlates with prostate phantom volume. There was no significant difference(p = .156). To measure the accurate volume of prostate with focal protrusion, its length should be measured exclude the protrusions.

  17. A decision support system for quantitative measurement of operational efficiency in a blood collection facility.

    Science.gov (United States)

    Kros, John F; Yim Pang, Robyn

    2004-04-01

    A decision support system (DSS) is presented that allows users to input, analyze, and output data derived from blood banking operations. The DSS developed is a hybrid system that is both data and model driven. The system provides information, models, and data manipulation tools to assist users in the quantitative measurement of the operational efficiency in a blood collection facility. A relational database was developed to address the four major variables, which impact the cost per unit of blood being collected. Using visual basic, a user interface and mathematical model were developed establishing the relationships to analyze cost per unit of collected blood. Using inputs from users and historical financial data, the DSS calculates the cost per unit as each of the major variables is altered. Real life situations by the mobile operations team at a blood collection facility were used to test the DSS.

  18. Macular thickness and macular volume measurements using spectral domain optical coherence tomography in normal Nepalese eyes

    Directory of Open Access Journals (Sweden)

    Pokharel A

    2016-03-01

    Full Text Available Amrit Pokharel,1 Gauri Shankar Shrestha,2 Jyoti Baba Shrestha2 1Department of Ophthalmology, Kathmandu Medical College Teaching Hospital, 2B P Koirala Lions Centre for Ophthalmic Studies, Institute of Medicine, Kathmandu, Nepal Purpose: To record the normative values for macular thickness and macular volume in normal Nepalese eyes. Methods: In all, 126 eyes of 63 emmetropic subjects (mean age: 21.17±6.76 years; range: 10–37 years were assessed for macular thickness and macular volume, using spectral domain-optical coherence tomography over 6×6 mm2 in the posterior pole. A fast macular thickness protocol was employed. Statistics such as the mean, median, standard deviation, percentiles, and range were used, while a P-value was set at 0.05 to test significance. Results: Average macular thickness and total macular volume were larger in males compared to females. With each year of increasing age, these variables decreased by 0.556 µm and 0.0156 mm3 for average macular thickness and total macular volume, respectively. The macular thickness was greatest in the inner superior section and lowest at the center of the fovea. The volume was greatest in the outer nasal section and thinnest in the fovea. The central subfield thickness (r=-0.243, P=0.055 and foveal volume (r=0.216, P=0.09 did not correlate with age. Conclusion: Males and females differ significantly with regard to macular thickness and macular volume measurements. Reports by other studies that the increase in axial length reduced thickness and volume, were negated by this study which found a positive correlation among axial length, thickness, and volume. Keywords: macular thickness, macular volume, optical coherence tomography, Nepal

  19. Imaging transient blood vessel fusion events in zebrafish by correlative volume electron microscopy.

    Directory of Open Access Journals (Sweden)

    Hannah E J Armer

    Full Text Available The study of biological processes has become increasingly reliant on obtaining high-resolution spatial and temporal data through imaging techniques. As researchers demand molecular resolution of cellular events in the context of whole organisms, correlation of non-invasive live-organism imaging with electron microscopy in complex three-dimensional samples becomes critical. The developing blood vessels of vertebrates form a highly complex network which cannot be imaged at high resolution using traditional methods. Here we show that the point of fusion between growing blood vessels of transgenic zebrafish, identified in live confocal microscopy, can subsequently be traced through the structure of the organism using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM and Serial Block Face/Scanning Electron Microscopy (SBF/SEM. The resulting data give unprecedented microanatomical detail of the zebrafish and, for the first time, allow visualization of the ultrastructure of a time-limited biological event within the context of a whole organism.

  20. MRI markers for mild cognitive impairment: comparisons between white matter integrity and gray matter volume measurements.

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    Full Text Available The aim of the study was to evaluate the value of assessing white matter integrity using diffusion tensor imaging (DTI for classification of mild cognitive impairment (MCI and prediction of cognitive impairments in comparison to brain atrophy measurements using structural MRI. Fifty-one patients with MCI and 66 cognitive normal controls (CN underwent DTI and T1-weighted structural MRI. DTI measures included fractional anisotropy (FA and radial diffusivity (DR from 20 predetermined regions-of-interest (ROIs in the commissural, limbic and association tracts, which are thought to be involved in Alzheimer's disease; measures of regional gray matter (GM volume included 21 ROIs in medial temporal lobe, parietal cortex, and subcortical regions. Significant group differences between MCI and CN were detected by each MRI modality: In particular, reduced FA was found in splenium, left isthmus cingulum and fornix; increased DR was found in splenium, left isthmus cingulum and bilateral uncinate fasciculi; reduced GM volume was found in bilateral hippocampi, left entorhinal cortex, right amygdala and bilateral thalamus; and thinner cortex was found in the left entorhinal cortex. Group classifications based on FA or DR was significant and better than classifications based on GM volume. Using either DR or FA together with GM volume improved classification accuracy. Furthermore, all three measures, FA, DR and GM volume were similarly accurate in predicting cognitive performance in MCI patients. Taken together, the results imply that DTI measures are as accurate as measures of GM volume in detecting brain alterations that are associated with cognitive impairment. Furthermore, a combination of DTI and structural MRI measurements improves classification accuracy.

  1. Measurement of cerebral blood flow rate and its relationship with brain function using optical coherence tomography

    Science.gov (United States)

    Liu, Jian; Wang, Yi; Zhao, Yuqian; Dou, Shidan; Ma, Yushu; Ma, Zhenhe

    2016-03-01

    Activity of brain neurons will lead to changes in local blood flow rate (BFR). Thus, it is important to measure the local BFR of cerebral cortex on research of neuron activity in vivo, such as rehabilitation evaluation after stroke, etc. Currently, laser Doppler flowmetry is commonly used for blood flow measurement, however, relatively low resolution limits its application. Optical coherence tomography (OCT) is a powerful noninvasive 3D imaging modality with high temporal and spatial resolutions. Furthermore, OCT can provide flow distribution image by calculating Doppler frequency shift which makes it possible for blood flow rate measurement. In this paper, we applied OCT to measure the blood flow rate of the primary motor cortex in rats. The animal was immobilized and anesthetized with isoflurane, an incision was made along the sagittal suture, and bone was exposed. A skull window was opened on the primary motor cortex. Then, blood flow rate changes in the primary motor cortex were monitored by our homemade spectral domain OCT with a stimulation of the passive movement of the front legs. Finally, we established the relationship between blood flow rate and the test design. The aim is to demonstrate the potential of OCT in the evaluation of cerebral cortex function.

  2. A Study on Anthropometric Measurements, Blood Pressure, Blood Sugar and Food Intakes Among Different Social Status and Ethnicities

    Directory of Open Access Journals (Sweden)

    Jafarirad

    2016-09-01

    Full Text Available Background Metabolic syndrome is a disorder that increases the risk of cardiovascular disease and diabetes. Objectives The aim of the study was to evaluate some risk factors of the metabolic syndrome and food intakes among people who lived in Ahvaz City, Iran. Methods It was a filed study that was conducted on 211 subjects who participated in health exhibition. Socioeconomic status and ethnicity were asked by a general questionnaire. Weight, height, body mass index, waist circumference (WC and WC to hip circumference ratio (WHR were obtained. Blood sugar was measured by a glucometer. Systolic and diastolic blood pressures were obtained and dietary intakes were assessed by a brief instrument. Results There was a significant difference in weight, height, WC, WHR and systolic blood pressure among different jobs. Workers had more intakes of cake and sweets. Arab subjects had more intakes of bread and fishes and Persians more intakes of vegetables. Soda, chocolate and candy were more consumed by Kurd ethnicity. Conclusions Job may be accounted as an important effective socioeconomic factor related to metabolic syndrome risk factors; also different cultures due to different ethnicities may have an influence on lifestyle and dietary intakes.

  3. Comparison between CT volume measurement and histopathological assessment of response to neoadjuvant therapy in rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pomerri, Fabio, E-mail: fabio.pomerri@unipd.it [Veneto Institute of Oncology IOV-IRCCS, via Gattamelata 64, 35128 Padua (Italy); Department of Medicine, University of Padua, via Giustiniani 2, 35128 Padua (Italy); Pucciarelli, Salvatore, E-mail: puc@unipd.it [Department of Oncological and Surgical Sciences, University of Padua, via Giustiniani 2, 35128 Padua (Italy); Gennaro, Gisella, E-mail: gisella.gennaro@pd.infn.it [Veneto Institute of Oncology IOV-IRCCS, via Gattamelata 64, 35128 Padua (Italy); Maretto, Isacco, E-mail: isac77@gmail.com [Veneto Institute of Oncology IOV-IRCCS, via Gattamelata 64, 35128 Padua (Italy); Nitti, Donato, E-mail: donato.nitti@unipd.it [Department of Oncological and Surgical Sciences, University of Padua, via Giustiniani 2, 35128 Padua (Italy); Muzzio, Pier Carlo, E-mail: pcmuzzio@unipd.it [Veneto Institute of Oncology IOV-IRCCS, via Gattamelata 64, 35128 Padua (Italy)

    2012-12-15

    Objectives: The aim of this study was to compare volume measurements on computed tomography (CT) images with histopathological assessments of chemoradiotherapy (CRT)-induced tumor regression in locally advanced rectal cancer (RC). Methods: In 25 patients (13 males, 12 females; median age, 63 years; age range, 44–79 years) with locally advanced RC treated with preoperative CRT and surgery, two radiologists measured tumor volume on CT images before and after CRT. CT-based tumor volumetry and the modified response evaluation criteria in solid tumors (mRECISTs) were compared with T and N downstaging after CRT, and with the tumor regression grade (TRG). Results: Tumor volumes were significantly smaller on CT images after CRT. The tumors regressed in 52% (13/25), 36% (9/25) and 40% (10/25) of patients, based on T downstaging, TRG and mRECIST findings, respectively. In terms of T downstaging, the pre- and post-CRT tumor volumes of responders and non-responders to the treatment differed statistically, while their tumor volume reduction rates and volume reductions according to the 65% mRECIST threshold did not. In terms of N downstaging and TRG, the differences between the responders’ and the non-responders’ pre- and post-CRT tumor volumes, tumor volume reduction rates, and mRECIST thresholds were never statistically significant. Conclusion: Measuring tumor size on CT images is of limited value in predicting the histopathological response to preoperative CRT in RC patients, so it may be unwise to select surgical treatment strategies based on CT volumetry.

  4. Effect of malaria on placental volume measured using three-dimensional ultrasound: a pilot study

    Directory of Open Access Journals (Sweden)

    Rijken Marcus J

    2012-01-01

    Full Text Available Abstract Background The presence of malaria parasites and histopathological changes in the placenta are associated with a reduction in birth weight, principally due to intrauterine growth restriction. The aim of this study was to examine the feasibility of studying early pregnancy placental volumes using three-dimensional (3D ultrasound in a malaria endemic area, as a small volume in the second trimester may be an indicator of intra-uterine growth restriction and placental insufficiency. Methods Placenta volumes were acquired using a portable ultrasound machine and a 3D ultrasound transducer and estimated using the Virtual Organ Computer-aided AnaLysis (VOCAL image analysis software package. Intra-observer reliability and limits of agreement of the placenta volume measurements were calculated. Polynomial regression models for the mean and standard deviation as a function of gestational age for the placental volumes of uninfected women were created and tested. Based on these equations each measurement was converted into a z -score. The z-scores of the placental volumes of malaria infected and uninfected women were then compared. Results Eighty-four women (uninfected = 65; infected = 19 with a posterior placenta delivered congenitally normal, live born, single babies. The mean placental volumes in the uninfected women were modeled to fit 5th, 10th, 50th, 90th and 95th centiles for 14-24 weeks' gestation. Most placenta volumes in the infected women were below the 50th centile for gestational age; most of those with Plasmodium falciparum were below the 10th centile. The 95% intra-observer limits of agreement for first and second measurements were ± 37.0 mL and ± 25.4 mL at 30 degrees and 15 degrees rotation respectively. Conclusion The new technique of 3D ultrasound volumetry of the placenta may be useful to improve our understanding of the pathophysiological constraints on foetal growth caused by malaria infection in early pregnancy.

  5. Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET

    DEFF Research Database (Denmark)

    Iida, H; Law, I; Pakkenberg, B

    2000-01-01

    formulated four mathematical models that describe the dynamic behavior of a freely diffusible tracer (H215O) in a region of interest (ROI) incorporating estimates of regional tissue flow that are independent of PVE. The current study was intended to evaluate the feasibility of these models and to establish...... a methodology to accurately quantify regional cerebral blood flow (CBF) corrected for PVE in cortical gray matter regions. Five monkeys were studied with PET after IV H2(15)O two times (n = 3) or three times (n = 2) in a row. Two ROIs were drawn on structural magnetic resonance imaging (MRI) scans and projected...... onto the PET images in which regional CBF values and the water perfusable tissue fraction for the cortical gray matter tissue (hence the volume of gray matter) were estimated. After the PET study, the animals were killed and stereologic analysis was performed to assess the gray matter mass...

  6. GEANT4 simulation of water volume fraction measurement in dehydrated crude oil

    Institute of Scientific and Technical Information of China (English)

    JING Chunguo; XING Guangzhong; LIU Bin

    2007-01-01

    Online measurement of water volume fraction (WVF) in dehydrated crude oil is a difficult task due to very little water in dehydrated crude oil and high precision requirements. We presents a method to measure water volume fraction in dehydrated crude oil with γ-ray densitometry. The Monte Carlo computer simulation packet GEANT4 was used to analyze the WVF measuring sensitivity of the γ-ray densitometry at different γ-ray energies, and effects of temperature, pressure, salinity and oil components on WVF measurement. The results show that the γ-ray densitome-try has high sensitivity in γ-ray energy ranges of 16~25 keV, and it can distinguish WVF changes of 0.0005. The calculated WVF decreases about 0.0002 with 1 ℃ of temperature increase and they have approximately linear relation with temperature when water volume fraction remains the same. Effects of pressure, salinity and oil components on water volume fraction can be neglected. Experiments were done to analyze sensitivity of the γ-ray densitometry. The results, as compared with simulations, demonstrate that simulation method is reliable and it is feasible to gauge low water volume fraction using low energy γ-rays.

  7. Blood Contamination in Saliva: Impact on the Measurement of Salivary Oxidative Stress Markers.

    Science.gov (United States)

    Kamodyová, Natália; Baňasová, Lenka; Janšáková, Katarína; Koborová, Ivana; Tóthová, Ľubomíra; Stanko, Peter; Celec, Peter

    2015-01-01

    Salivary oxidative stress markers represent a promising tool for monitoring of oral diseases. Saliva can often be contaminated by blood, especially in patients with periodontitis. The aim of our study was to examine the impact of blood contamination on the measurement of salivary oxidative stress markers. Saliva samples were collected from 10 healthy volunteers and were artificially contaminated with blood (final concentration 0.001-10%). Next, saliva was collected from 12 gingivitis and 10 control patients before and after dental hygiene treatment. Markers of oxidative stress were measured in all collected saliva samples. Advanced oxidation protein products (AOPP), advanced glycation end products (AGEs), and antioxidant status were changed in 1% blood-contaminated saliva. Salivary AOPP were increased in control and patients after dental treatment (by 45.7% and 34.1%, p Saliva samples with 1% blood contamination are visibly discolored and can be excluded from analyses without any specific biochemic detection of blood constituents. Salivary markers of oxidative stress were significantly altered in blood-contaminated saliva in control and patients with gingivitis after dental hygiene treatment.

  8. Prognostic significance of distal blood pressure measurements in patients with severe ischaemia

    DEFF Research Database (Denmark)

    Paaske, William; Tønnesen, K H

    1980-01-01

    The clinical course was followed and the ankle and toe blood pressures were measured with the strain gauge technique on 5 occasions during 2 years in 43 patients with pain at rest and/or ischaemic ulceration due to severe ischaemia of the legs on the basis of occlusive arterial disease. Although...... arteriosclerosis of the legs in non-diabetic patients is generally considered a benign disease from the standpoint of limb survival, the critical level of TPI (systolic toe blood pressure/systolic arm blood pressure) was found to be 0.07 as a TPI below this value was associated with an overall 82% risk...

  9. In vivo μPIV measurements of blood velocity in small vessels of a rat model

    Science.gov (United States)

    Leong, Chia Min; Russell, John; Connor, Nadine; Honkanen, Markus; Wei, Timothy

    2009-11-01

    Aging-related muscular changes have been shown to affect voice production. There is correlation between muscular changes and changes in capillary hemodynamics and structure with aging. Alterations in oxygen transport to cells and tissues at the capillary level has been hypothesized as one of the key factors that causes muscular changes thus voice production. Since oxygen transport is related to hemodynamics, we start by measuring blood velocity in capillaries of cremaster muscle of a living rat. The μPIV technique is adapted for measuring blood velocity where red blood cells are used as `seeding particles'. The accuracy of the μPIV measurements are determined by comparison with results obtained using other techniques such as particle tracking velocimetry (PTV). Finally, challenges in measuring flow through three-dimensional larynx geometry will be discussed.

  10. Plasma concentrations of blood coagulation factor VII measured by immunochemical and amidolytic methods

    DEFF Research Database (Denmark)

    Bladbjerg, E-M; Gram, J; Jespersen, J

    2000-01-01

    Ever since the coagulant activity of blood coagulation factor VII (FVII:C) was identified as a risk indicator of cardiac death, a large number of studies have measured FVII protein concentrations in plasma. FVII protein concentrations are either measured immunologically with an ELISA method (FVII......:Ag) or estimated with an amidolytic method (FVII:Am). We have investigated whether FVII:Am is a valuable alternative to FVII:Ag. FVII:Ag and FVII:Am were measured in 147 plasma samples from blood donors, patients on oral anticoagulant therapy, postmenopausal women on hormone replacement therapy, in postprandial...

  11. Quantifying the link between anatomical connectivity, gray matter volume and regional cerebral blood flow: an integrative MRI study.

    Directory of Open Access Journals (Sweden)

    Bálint Várkuti

    Full Text Available BACKGROUND: In the graph theoretical analysis of anatomical brain connectivity, the white matter connections between regions of the brain are identified and serve as basis for the assessment of regional connectivity profiles, for example, to locate the hubs of the brain. But regions of the brain can be characterised further with respect to their gray matter volume or resting state perfusion. Local anatomical connectivity, gray matter volume and perfusion are traits of each brain region that are likely to be interdependent, however, particular patterns of systematic covariation have not yet been identified. METHODOLOGY/PRINCIPAL FINDINGS: We quantified the covariation of these traits by conducting an integrative MRI study on 23 subjects, utilising a combination of Diffusion Tensor Imaging, Arterial Spin Labeling and anatomical imaging. Based on our hypothesis that local connectivity, gray matter volume and perfusion are linked, we correlated these measures and particularly isolated the covariation of connectivity and perfusion by statistically controlling for gray matter volume. We found significant levels of covariation on the group- and regionwise level, particularly in regions of the Default Brain Mode Network. CONCLUSIONS/SIGNIFICANCE: Connectivity and perfusion are systematically linked throughout a number of brain regions, thus we discuss these results as a starting point for further research on the role of homology in the formation of functional connectivity networks and on how structure/function relationships can manifest in the form of such trait interdependency.

  12. Corneal Volume Measurements with Pentacam for Detection of Keratoconus and Subclinical Keratoconus

    OpenAIRE

    Nurullah Çağıl; Nagihan Uğurlu; Hasan Basri Çakmak; Sucattin İlker Kocamış; Hüseyin Simavlı; Şaban Şimşek

    2013-01-01

    Pur po se: To estimate the sensitivity and specificity of corneal volume (CV) measurements in discriminating keratoconus and subclinical keratoconus from normal corneas. Ma te ri al and Met hod: Clinical records and Pentacam measurements of ninety-four patients with keratoconus, 36 patients with subclinical keratoconus, and 166 refractive surgery candidates with normal corneas were evaluated retrospectively. CV within 3, 5, 7, and 10 mm circles around the central cornea was measur...

  13. LASER-DOPPLER BLOOD FLOWMETRY USING 2 WAVELENGTHS - MONTE-CARLO SIMULATIONS AND MEASUREMENTS

    NARCIS (Netherlands)

    KOELINK, MH; DEMUL, FFM; GREVE, J; GRAAFF, R; DASSEL, ACM; AARNOUDSE, JG

    1994-01-01

    A new laser Doppler blood flowmeter for measuring skin perfusion is presented. The flowmeter consists of a probe that uses two different wavelengths and is able to measure at different depths. It may be used to distinguish the superficial microcirculation of the skin providing nutritional flow and t

  14. The measurement of digital systolic blood pressure by strain gauge technique

    DEFF Research Database (Denmark)

    Nielsen, P E; Bell, G; Lassen, N A

    1972-01-01

    The systolic blood pressure on the finger, toe, and ankle has been measured by a strain gauge technique in 10 normal subjects aged 17-31 years and 14 normal subjects aged 43-57 years. The standard deviation in repeated measurements lies between 2 and 6 mm Hg. The finger pressure in the younger...

  15. Revisiting the returns-volume relationship: Time variation, alternative measures and the financial crisis

    Science.gov (United States)

    Cook, Steve; Watson, Duncan

    2017-03-01

    Following its introduction in the seminal study of Osborne (1959), a voluminous literature has emerged examining the returns-volume relationship for financial assets. The present paper revisits this relationship in an examination of the FTSE100 which extends the existing literature in two ways. First, alternative daily measures of the FTSE100 index are used to create differing returns and absolute returns series to employ in an examination of returns-volume causality. Second, rolling regression analysis is utilised to explore potential time variation in the returns-volume relationship. The findings obtained depict a hitherto unconsidered complexity in this relationship with the type of returns series considered and financial crisis found to be significant underlying factors. The implications of the newly derived results for both the understanding of the nature of the returns-volume relationship and the development of theories in connection to it are discussed.

  16. Frequency of Blood Pressure Measuring According to the Degree of Working Population Education in Canton Sarajevo

    Science.gov (United States)

    Brankovic, Suada; Pilav, Aida; Macak-Hadziomerovic, Amra; Rama, Admir; Segalo, Mersa

    2013-01-01

    Introduction: Hypertension (high blood pressure) is one of the most widely spread modern diseases and one of the leading risk factors for heart and blood vessel diseases, particularly stroke and coronary heart disease. The prevalence of hypertension is about 25% in adults. Many studies show that blood pressure tends to have lower values among people with higher education levels. Goal: To determine the frequency of measurement and control of blood pressure in relation to the level of education of the active working population of the Sarajevo Canton. Material and methods: The study was conducted on 443 subjects randomly selected from the categories of the active working population of the Sarajevo Canton. The study was conducted at the Center for Heart, Clinical Center University of Sarajevo University through the project “Prevention of risk factors for cardiovascular disease in the active working population of the Sarajevo Canton”. Respondents were at age in range from 18-65 years, who have voluntarily joined the study. Results: Of 443 (100%) of the respondents 153 (34.5%) were males compared to females whose participation in the sample was 290 (65.5%). Regarding the structure of respondents, the majority of them 213 (48.1%) graduated faculty, 142 (32, 1%) graduated secondary vocational schools and 66 (14.9%) with a higher degree, with the lowest number with completed grammar school (1.4%) and secondary school (0.5%). Blood pressure never measure 16 (3.6%) of respondents, which is not insignificant number, more than 5 years ago 23 (5.2%), within last 1-5 years 90 (20.3%), in the past 12 months 88 (19.9% ) and 226 (51%) measured the blood pressure in the past 6 months. Blood pressure never controlled 4.33% of respondents with secondary or higher education and 2.82% of the respondents with university education. Chi-square test showed a difference between education and the prevalence of blood pressure, χ2=7.812; DF=8; p=0.045. Conclusion: Monitoring of blood

  17. Development of a diagnostic sensor for measuring blood cell concentrations during haemoconcentration

    Science.gov (United States)

    Robertson, Craig A.; Gourlay, Terence

    2016-01-01

    Background: HemoSep® is a commercial ultrafiltration and haemoconcentration device for the concentration of residual bypass blood following surgery. This technology is capable of reducing blood loss in cardiac and other types of “clean site” procedures, including paediatric surgery. Clinical feedback suggested that the device would be enhanced by including a sensor technology capable of discerning the concentration level of the processed blood product. We sought to develop a novel sensor that can, using light absorption, give an accurate estimate of packed cell volume (PCV). Materials and methods: A sensor-housing unit was 3D printed and the factors influencing the sensor’s effectiveness – supply voltage, sensitivity and emitter intensity - were optimised. We developed a smart system, using comparator circuitry capable of visually informing the user when adequate PCV levels (⩾35%) are attained by HemoSep® blood processing, which ultimately indicates that the blood is ready for autotransfusion. Results: Our data demonstrated that the device was capable of identifying blood concentration at and beyond the 35% PCV level. The device was found to be 100% accurate at identifying concentration levels of 35% from a starting level of 20%. Discussion: The sensory capability was integrated into HemoSep’s® current device and is designed to enhance the user’s clinical experience and to optimise the benefits of HemoSep® therapy. The present study focused on laboratory studies using bovine blood. Further studies are now planned in the clinical setting to confirm the efficacy of the device. PMID:27591743

  18. In vivo noninvasive measurement of preprandial and postprandial blood glucose using optical coherence tomography

    Science.gov (United States)

    Zhang, Ying; Zhang, Xiyang; Li, Zhifang; Li, Hui

    2016-10-01

    Blood glucose concentration measurement is essential for the diagnosis and treatment of diabetes. However, conventional glucose measurement methods are invasive and not suitable for real-time monitoring. This study demonstrated a noninvasive blood glucose measurement method using optical coherence tomography to image human lip in vivo. Optical coherence tomography (OCT) is a noninvasive and depth-resolved technique capable of acquiring tissue structure images in real time. Human lip has very thin skin and is full of blood vessels, which is appropriate for noninvasive glucose measurement. To verify the feasibility of OCT for glucose concentration monitoring, two groups of OCT imaging data were obtained from human lips of normal people. In one group, OCT images of lip were acquired from people on an empty stomach. In the other group, the same sites of lip were observed by OCT 2 hours after breakfast. Evident differences were found from two groups of OCT images that correspond to preprandial glucose and 2- hour postprandial glucose, respectively. The relationship between OCT image and blood glucose concentration was investigated. The result indicates that OCT possesses considerable prospects in terms of noninvasive blood glucose measurement.

  19. [Accuracy of the oscillometric method to measure blood pressure in children

    Science.gov (United States)

    Rego Filho, E A; Mello, S F; Silva, C R; Vituri, D W; Bazoni, E; Gordan, L N

    1999-01-01

    OBJECTIVE: The aim of this study is to analyze the substitution of the standard auscultatory method by the oscillometric blood pressure monitor, independently of the validity of the intraarterial blood pressure measurement. The accuracy of the automatic oscillometric monitor was compared to the auscultatory mercury manometer blood pressure measurement in apparently healthy school age children. METHODS: A device able to perform 3 simultaneous readings are used: one reading by the monitor and the others by two "blind" observers. We studied 72 school age children with the following characteristics: mean age 9.5 (6.1-16.1) and 39 males (54.2%). RESULTS: The difference for the systolic and diastolic blood pressure obtained by the monitor was in average + 6.2 mmHg and + 10.0 mmHg, respectively, when compared to the observer's readings. There was neither a good correlation nor a good agreement between the two observers and the monitor in the blood pressure determination. CONCLUSIONS: We concluded that the substitution of the standard auscultatory method for the non-invasive oscillometric method to measure blood pressure in school age children can not be generally recommended.

  20. A Surface Heat Disturbance Method for Measuring Local TIssue Blood Perfusion Rate

    Institute of Scientific and Technical Information of China (English)

    PengJianshu; TianYongquan

    1996-01-01

    A non-damage method for measuring local tissue blood perfusion rate by surface heat disturbance and its two special embodiments for realizing this measurement are presented in this paper,In the derivation of mathematical model,the Pennes equation is used,and two parameters which are very diffcult to be known-the arterial blood temperature Ta and the metabolic heat generation rate qm,have been eliminated.So if has provided a feasible basis for application.In this paper,the performance and the adaptable condition of the measurement method and its structure peculiarities are discussed over a wide variety of parameters.Moreover,the effectiveness of the measurement method has been demonstrated by means of the quantitative measurement of tissue in vitro,the comparative measurement of animal under artificial perfusion and the dependence measurement in human body.

  1. Cerebral hemodynamic changes measured by gradient-echo or spin-echo bolus tracking and its correlation to changes in ICA blood flow measured by phase-mapping MRI

    DEFF Research Database (Denmark)

    Marstrand, J.R.; Rostrup, Egill; Garde, Ellen;

    2001-01-01

    Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC-MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase-mapping. Also examined...... was the effect of repeated bolus injections. CBF, cerebral blood volume (CBV), and mean transit time (MTT) were calculated by singular value decomposition (SVD) and by deconvolution using an exponential function as kernel. The results showed no dependency on calculation method. GE-EPI measured a significant...... increase in CBF and CBV in response to ACZ, while SE-EPI measured a significant increase in CBV and MTT. CBV and MTT change measured by SE-EPI was sensitive to previous bolus injections. There was a significant linear relation between change in CBF measured by GE-EPI and change in ICA flow. In conclusion...

  2. Cost estimation of hypertension management based on home blood pressure monitoring alone or combined office and ambulatory blood pressure measurements.

    Science.gov (United States)

    Boubouchairopoulou, Nadia; Karpettas, Nikos; Athanasakis, Kostas; Kollias, Anastasios; Protogerou, Athanase D; Achimastos, Apostolos; Stergiou, George S

    2014-10-01

    This study aims at estimating the resources consumed and subsequent costs for hypertension management, using home blood pressure (BP) monitoring (HBPM) alone versus combined clinic measurements and ambulatory blood pressure monitoring (C/ABPM). One hundred sixteen untreated hypertensive subjects were randomized to use HBPM or C/ABPM for antihypertensive treatment initiation and titration. Health resources utilized within 12-months follow-up, their respective costs, and hypertension control were assessed. The total cost of the first year of hypertension management was lower in HBPM than C/ABPM arm (€1336.0 vs. €1473.5 per subject, respectively; P cost was identical in both arms. There was no difference in achieved BP control and drug expenditure (HBPM: €233.1 per subject; C/ABPM: €247.6 per subject; P = not significant), whereas the cost of BP measurements and/or visits was higher in C/ABPM arm (€393.9 vs. €516.9, per patient, respectively P cost for subsequent years (>1) was €348.9 and €440.2 per subject, respectively for HBPM and C/ABPM arm and €2731.4 versus €3234.3 per subject, respectively (P cost than C/ABPM, and the same trend is observed in 5-year projection. The results on the resources consumption can be used to make cost estimates for other health-care systems.

  3. Double-echo perfusion-weighted MR imaging: basic concepts and application in brain tumors for the assessment of tumor blood volume and vascular permeability

    Energy Technology Data Exchange (ETDEWEB)

    Uematsu, Hidemasa [University of Fukui, Department of Radiology, Faculty of Medical Sciences, Fukui (Japan); Maeda, Masayuki [Mie University School of Medicine, Department of Radiology, Mie (Japan)

    2006-01-01

    Perfusion-weighted magnetic resonance (MR) imaging using contrast agents plays a key role in characterizing tumors of the brain. We have shown that double-echo perfusion-weighted MR imaging (DEPWI) is potentially useful in assessing brain tumors. Quantitative indices, such as tumor blood volume, are obtained using DEPWI, which allows correction of underestimation of tumor blood volume due to leakage of contrast agents from tumor vessels, in addition to simultaneous acquisition of tumor vessel permeability. This article describes basic concepts of DEPWI and demonstrates clinical applications in brain tumors. (orig.)

  4. Accuracy of point-of-care blood glucose measurements in critically ill patients in shock.

    Science.gov (United States)

    Garingarao, Carlo Jan Pati-An; Buenaluz-Sedurante, Myrna; Jimeno, Cecilia Alegado

    2014-09-01

    A widely used method in monitoring glycemic status of ICU patients is point-of-care (POC) monitoring devices. A possible limitation to this method is altered peripheral blood flow in patients in shock, which may result in over/underestimations of their true glycemic status. This study aims to determine the accuracy of blood glucose measurements with a POC meter compared to laboratory methods in critically ill patients in shock. POC blood glucose was measured with a glucose-1-dehydrogenase-based reflectometric meter. The reference method was venous plasma glucose measured by a clinical chemistry analyzer (glucose oxidase-based). Outcomes assessed were concordance to ISO 15197:2003 minimum accuracy criteria for glucose meters, bias in glucose measurements obtained by the 2 methods using Bland-Altman analysis, and clinical accuracy through modified error grid analysis. A total of 186 paired glucose measurements were obtained. ISO 2003 accuracy criteria were met in 95.7% and 79.8% of POC glucose values in the normotensive and hypotensive group, respectively. Mean bias for the normotensive group was -12.4 mg/dL, while mean bias in the hypotensive group was -34.9 mg/dL. POC glucose measurements within the target zone for clinical accuracy were 90.2% and 79.8% for the normotensive and hypotensive group, respectively. POC blood glucose measurements were significantly less accurate in the hypotensive subgroup of ICU patients compared to the normotensive group. We recommend a lower threshold in confirming POC blood glucose with a central laboratory method if clinically incompatible. In light of recently updated accuracy standards, we also recommend alternative methods of glucose monitoring for the ICU population as a whole regardless of blood pressure status.

  5. Self-measurement of blood pressure at home reduces the need for antihypertensive drugs - A randomized, controlled trial

    NARCIS (Netherlands)

    Verberk, Willem J.; Kroon, Abraham A.; Lenders, Jacques W. M.; Kessels, Alfons G. H.; van Montfrans, Gert A.; Smit, Andries J.; van der Kuy, Paul-Hugo M.; Nelemans, Patricia J.; Rennenberg, Roger J. M. W.; Grobbee, Diederick E.; Beltman, Frank W.; Joore, Manuela A.; Brunenberg, Danielle E. M.; Dirksen, Carmen; Thien, Theo; de Leeuw, Peter W.

    2007-01-01

    It is still uncertain whether one can safely base treatment decisions on self- measurement of blood pressure. In the present study, we investigated whether antihypertensive treatment based on self- measurement of blood pressure leads to the use of less medication without the loss of blood pressure c

  6. Relations between various measures of iodine intake and thyroid volume, thyroid nodularity, and serum thyroglobulin

    DEFF Research Database (Denmark)

    Rasmussen, Lone Banke; Ovesen, L.; Bulow, I.

    2002-01-01

    plus supplements, iodine intake from diet/kg body wt, and milk intake (P = 0.001 for all), but not urinary iodine excretion measured as a concentration (P = 0.40). All measures of iodine intake were significantly related to serum thyroglobulin concentration (P less than or equal to 0.002), but only...... excretion measured as a urinary concentration, predicted thyroid volume. Serum thyroglobulin concentration appears to be a good marker of iodine status. Subgroups with low intakes of milk and milk products had an increased risk of thyroid disease.......Background: Iodine intake can be measured in various ways, and each method may have advantages and disadvantages. Objective: We sought to investigate the potential associations of various measures of iodine intake with thyroid volume, prevalence of thyroid nodules, and serum thyroglobulin. We also...

  7. Arterial pressure variations as parameters of brain perfusion in response to central blood volume depletion and repletion

    Directory of Open Access Journals (Sweden)

    Anne-Sophie G.T. Bronzwaer

    2014-04-01

    Full Text Available Rationale:A critical reduction in central blood volume (CBV is often characterized by hemodynamic instability. Restoration of a volume deficit may be established by goal-directed fluid therapy guided by respiration-related variation in systolic- and pulse pressure (SPV and PPV. Stroke volume index (SVI serves as a surrogate end-point of a fluid challenge but tissue perfusion itself has not been addressed. Objective: To delineate the relationship between arterial pressure variations, SVI and regional brain perfusion during CBV depletion and repletion in spontaneously breathing volunteers. Methods: This study quantified in 14 healthy subjects (11 male the effects of CBV depletion (by 30 and 70 degrees passive head-up tilt (HUT and a fluid challenge (by tilt back on CBV (thoracic admittance, mean middle cerebral artery (MCA blood flow velocity (Vmean, SVI, cardiac index (CI , PPV and SPV. Results: PPV (103±89%, p< 0.05 and SPV (136±117%, p< 0.05 increased with progression of central hypovolemia manifested by a reduction in thoracic admittance (11±5%, p< 0.001, SVI (28±6%, p< 0.001, CI (6±8%, p< 0.001 and MCAVmean (17±7%, p< 0.05 but not in arterial pressure. The reduction in MCAVmean correlated to the fall in SVI (R2=0.52, p< 0.0001 and inversely to PPV and SPV (R2=0.46 (p< 0.0001 and R2=0.45 (p< 0.0001, respectively. PPV and SPV predicted a ≥15% reduction in MCAVmean and SVI with comparable sensitivity (67%/ 67% vs. 63%/ 68% respectively and specificity (89%/94% vs. 89%/94%, respectively. A rapid fluid challenge by tilt-back restored all parameters to baseline values within one minute. Conclusion: In spontaneously breathing subjects, a reduction in MCAVmean was related to an increase in PPV and SPV during graded CBV depletion and repletion. Specifically, PPV and SPV predicted changes in both SVI and MCAVmean with comparable sensitivity and specificity, however the predictive value is limited in spontaneously breathing subjects.

  8. Quantitative radiology: automated measurement of polyp volume in computed tomography colonography using Hessian matrix-based shape extraction and volume growing

    Science.gov (United States)

    Epstein, Mark L.; Obara, Piotr R.; Chen, Yisong; Liu, Junchi; Zarshenas, Amin; Makkinejad, Nazanin; Dachman, Abraham H.

    2015-01-01

    Background Current measurement of the single longest dimension of a polyp is subjective and has variations among radiologists. Our purpose was to develop a computerized measurement of polyp volume in computed tomography colonography (CTC). Methods We developed a 3D automated scheme for measuring polyp volume at CTC. Our scheme consisted of segmentation of colon wall to confine polyp segmentation to the colon wall, extraction of a highly polyp-like seed region based on the Hessian matrix, a 3D volume growing technique under the minimum surface expansion criterion for segmentation of polyps, and sub-voxel refinement and surface smoothing for obtaining a smooth polyp surface. Our database consisted of 30 polyp views (15 polyps) in CTC scans from 13 patients. Each patient was scanned in the supine and prone positions. Polyp sizes measured in optical colonoscopy (OC) ranged from 6-18 mm with a mean of 10 mm. A radiologist outlined polyps in each slice and calculated volumes by summation of volumes in each slice. The measurement study was repeated 3 times at least 1 week apart for minimizing a memory effect bias. We used the mean volume of the three studies as “gold standard”. Results Our measurement scheme yielded a mean polyp volume of 0.38 cc (range, 0.15-1.24 cc), whereas a mean “gold standard” manual volume was 0.40 cc (range, 0.15-1.08 cc). The “gold-standard” manual and computer volumetric reached excellent agreement (intra-class correlation coefficient =0.80), with no statistically significant difference [P (F≤f) =0.42]. Conclusions We developed an automated scheme for measuring polyp volume at CTC based on Hessian matrix-based shape extraction and volume growing. Polyp volumes obtained by our automated scheme agreed excellently with “gold standard” manual volumes. Our fully automated scheme can efficiently provide accurate polyp volumes for radiologists; thus, it would help radiologists improve the accuracy and efficiency of polyp volume

  9. Ultrasonic methods for measuring liquid viscosity and volume percent of solids

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S.H.; Chien, H.T.; Raptis, A.C.

    1997-02-01

    This report describes two ultrasonic techniques under development at Argonne National Laboratory (ANL) in support of the tank-waste transport effort undertaken by the U.S. Department of Energy in treating low-level nuclear waste. The techniques are intended to provide continuous on-line measurements of waste viscosity and volume percent of solids in a waste transport line. The ultrasonic technique being developed for waste-viscosity measurement is based on the patented ANL viscometer. Focus of the viscometer development in this project is on improving measurement accuracy, stability, and range, particularly in the low-viscosity range (<30 cP). A prototype instrument has been designed and tested in the laboratory. Better than 1% accuracy in liquid density measurement can be obtained by using either a polyetherimide or polystyrene wedge. To measure low viscosities, a thin-wedge design has been developed and shows good sensitivity down to 5 cP. The technique for measuring volume percent of solids is based on ultrasonic wave scattering and phase velocity variation. This report covers a survey of multiple scattering theories and other phenomenological approaches. A theoretical model leading to development of an ultrasonic instrument for measuring volume percent of solids is proposed, and preliminary measurement data are presented.

  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...... (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...

  11. Classification of diabetes and measurement of blood glucose concentration noninvasively using near infrared spectroscopy

    Science.gov (United States)

    Li, Zhe; Li, Gang; Yan, Wen-Juan; Lin, Ling

    2014-11-01

    Developing noninvasive blood glucose monitoring method is an to immense need to alleviate the pain and suffering of diabetics associated with the frequent pricking of skin for taking blood sample. A hybrid algorithm for multivariate calibration is proposed to improve the prediction performance of classification of diabetes and measurement of blood glucose concentration by near infrared (NIR) spectroscopy noninvasively. The algorithm is based on wavelet prism modified uninformative variable elimination approach (WP-mUVE) combined with least squares support vector machine (LSSVM), named as WP-mUVE-LSSVM. The method is successfully applied to diabetic classification experiment (in vivo) and blood glucose concentration measurement experiment (in vivo) respectively. Human tongue is selected as the measuring site in this study. To evaluate effectiveness of pretreatment method and quality of calibration models, several usually used pretreatment methods and kernel functions of LSSVM are introduced comparing with our method. Higher quality data is obtained by our pretreatment method owing to the elimination of varying background and noise of spectra data simultaneously. Better prediction accuracy and adaptability are obtained by LSSVM model with radial basis kernel function. The results indicate that WP-mUVE-LSSVM holds promise for the classification of diabetes and measurement of blood glucose concentration noninvasively based on human tongue using NIR spectroscopy.

  12. Plasma volume changes during hypoglycaemia

    DEFF Research Database (Denmark)

    Hilsted, J; Bendtsen, F; Christensen, N J

    1990-01-01

    To investigate whether previously reported changes in venous blood volume and composition induced by acute hypoglycaemia in humans are representative for the entire body we measured erythrocyte 51Cr content, haematocrit, plasma volume, intravascular albumin content and transcapillary escape rate...... of albumin in arterial and venous blood in seven healthy subjects before and during insulin-induced hypoglycaemia. In both vascular sites blood 51Cr content and the haematocrit increased, plasma volume and intravascular albumin content decreased and the transcapillary escape rate of albumin increased during...

  13. Repeated Blood Pressure Measurements in Childhood in Prediction of Hypertension in Adulthood.

    Science.gov (United States)

    Oikonen, Mervi; Nuotio, Joel; Magnussen, Costan G; Viikari, Jorma S A; Taittonen, Leena; Laitinen, Tomi; Hutri-Kähönen, Nina; Jokinen, Eero; Jula, Antti; Cheung, Michael; Sabin, Matthew A; Daniels, Stephen R; Raitakari, Olli T; Juonala, Markus

    2016-01-01

    Hypertension may be predicted from childhood risk factors. Repeated observations of abnormal blood pressure in childhood may enhance prediction of hypertension and subclinical atherosclerosis in adulthood compared with a single observation. Participants (1927, 54% women) from the Cardiovascular Risk in Young Finns Study had systolic and diastolic blood pressure measurements performed when aged 3 to 24 years. Childhood/youth abnormal blood pressure was defined as above 90th or 95th percentile. After a 21- to 31-year follow-up, at the age of 30 to 45 years, hypertension (>140/90 mm Hg or antihypertensive medication) prevalence was found to be 19%. Carotid intima-media thickness was examined, and high-risk intima-media was defined as intima-media thickness >90th percentile or carotid plaques. Prediction of adulthood hypertension and high-risk intima-media was compared between one observation of abnormal blood pressure in childhood/youth and multiple observations by improved Pearson correlation coefficients and area under the receiver operating curve. When compared with a single measurement, 2 childhood/youth observations improved the correlation for adult systolic (r=0.44 versus 0.35, Pblood pressure. In addition, 2 abnormal childhood/youth blood pressure observations increased the prediction of hypertension in adulthood (0.63 for 2 versus 0.60 for 1 observation, P=0.003). When compared with 2 measurements, third observation did not provide any significant improvement for correlation or prediction (P always >0.05). A higher number of childhood/youth observations of abnormal blood pressure did not enhance prediction of adult high-risk intima-media thickness. Compared with a single measurement, the prediction of adult hypertension was enhanced by 2 observations of abnormal blood pressure in childhood/youth.

  14. Multibeam volume acoustic backscatter imagery and reverberation measurements in the northeastern Gulf of Mexico

    Science.gov (United States)

    Gallaudet, Timothy C.; deMoustier, Christian P.

    2002-08-01

    Multibeam volume acoustic backscatter imagery and reverberation measurements are derived from data collected in 200-m-deep waters in the northeastern Gulf of Mexico, with the Toroidal Volume Search Sonar (TVSS), a 68-kHz cylindrical sonar operated by the U.S. Navy's Coastal System Station. The TVSS's 360-degree vertical imaging plane allows simultaneous identification of multiple volume scattering sources and their discrimination from backscatter at the sea surface or the seafloor. This imaging capability is used to construct a three-dimensional representation of a pelagic fish school near the bottom. Scattering layers imaged in the mixed layer and upper thermocline are attributed to assemblages of epipelagic zooplankton. The fine scale patchiness of these scatterers is assessed with the two-dimensional variance spectra of vertical volume scattering strength images in the upper and middle water column. Mean volume reverberation levels exhibit a vertical directionality which is attributed to the volume scattering layers. Boundary echo sidelobe interference and reverberation is shown to be the major limitation in obtaining bioacoustic data with the TVSS. Because net tow and trawl samples were not collected with the acoustic data, the analysis presented is based upon comparison to previous biologic surveys in the northeastern Gulf of Mexico and reference to the bioacoustic literature. copyright 2002 Acoustical Society of America.

  15. Relation of the volume of the olfactory bulb to psychophysical measures of olfactory function.

    Science.gov (United States)

    Mazal, Patricia Portillo; Haehner, Antje; Hummel, Thomas

    2016-01-01

    The aim of this review is to investigate whether changes in olfactory bulb volume relate to changes in specific olfactory functions. We studied currently available peer-reviewed articles on the volume of the human olfactory bulb that also included a psychophysical measure of olfactory function. In the present review, we observed a very clear and consistent correlation between general olfactory function and olfactory bulb (OB) volume. We were not able to find a clear relationship between a specific smell component and OB volume, even when analyzing pathologic conditions separately. In some cases, changes were observed for different subtests, but these changes did not significantly correlate with OB volume or had only a borderline correlation. In other cases, we found contradictory data. Several factors may contribute to the difficulties in finding correlations with the different components of smell: (1) the OB volume may be influenced by information from olfactory receptor neurons (bottom-up effect), information from central nervous system (top-down effect) and by direct damage; (2) most pathologic conditions affect more than one area of the olfactory pathway; (3) small sample sizes of hyposmic subjects were used. We believe that it is necessary to do further studies with larger numbers of subjects to answer the currently investigated question.

  16. Blood pressure measurement of all five fingers by strain gauge plethysmography

    DEFF Research Database (Denmark)

    Hirai, M; Nielsen, S L; Lassen, N A

    1976-01-01

    The aim of the present paper was to study the methodological problems involved in measuring systolic blood pressure in all five fingers by the strain gauge technique. In 24 normal subjects, blood pressure at the proximal phalanx of finger I and both at the proximal and the intermediate phalanx...... of the other fingers was measured using a 24-mm-wide cuff. Blood pressure at the proximal phalanx was higher than that at the intermediate phalanx in all fingers except finger V. The difference of blood pressure values corresponded well with circumference of the finger. In 15 normal subjects, blood pressure...... of the mean values was larter with the 27-mm-wide cuff than with the 24-mm-wide cuff, the 24-mm-wide cuff was considered to be most suitable for clinical use in fingers I, II, III, and IV. By using the 20-mm-wide cuff in finger V and the 24-mm-wide cuff in the other fingers, normal value of finger blood...

  17. Early development of arterial spin labeling to measure regional brain blood flow by MRI.

    Science.gov (United States)

    Koretsky, Alan P

    2012-08-15

    Two major avenues of work converged in the late 1980's and early 1990's to give rise to brain perfusion MRI. The development of anatomical brain MRI quickly had as a major goal the generation of angiograms using tricks to label flowing blood in macroscopic vessels. These ideas were aimed at getting information about microcirculatory flow as well. Over the same time course the development of in vivo magnetic resonance spectroscopy had as its primary goal the assessment of tissue function and in particular, tissue energetics. For this the measurement of the delivery of water to tissue was critical for assessing tissue oxygenation and viability. The measurement of the washin/washout of "freely" diffusible tracers by spectroscopic based techniques pointed the way for quantitative approaches to measure regional blood flow by MRI. These two avenues came together in the development of arterial spin labeling (ASL) MRI techniques to measure regional cerebral blood flow. The early use of ASL to measure brain activation to help verify BOLD fMRI led to a rapid development of ASL based perfusion MRI. Today development and applications of regional brain blood flow measurements with ASL continues to be a major area of activity.

  18. Measurement of streaming potentials of mammalian blood vessels, aorta and vena cava, in vivo.

    Science.gov (United States)

    Sawyer, P N; Himmelfarb, E; Lustrin, I; Ziskind, H

    1966-09-01

    Attempts to measure streaming potentials in large rabbit blood vessels in vivo have been carried out. Streaming potentials, V(89), were measured by the introduction of microelectrodes through the wall of the blood vessel at separations greater than 1 cm. The outputs from these electrodes fed through calomel cells were amplified and recorded directly by using an Electronics for Medicine photorecorder (White Plains, N. Y.). "Effective streaming currents" were determined by running the output through a low impedence galvanometer while simultaneously measuring the resistance of the circuit V(8) were, therefore, calculated from two measurements and compared. Flow through vessels studied was measured using two different electromagnetic flowmeters. The results indicate that V(8) present in both aorta and vena cava are of the order of 5 to 10 mv. By using the Helmholtz-Smoluchowski equation into which flow was reintegrated, the numbers yield zeta potentials approximating 0.1 to 0.4 v in both aorta and vena cava. This number approaches the apparent upper limit for zeta (actually "interfacial potentials") potentials in biological systems. The measured "i.f." potential is considered as the interreaction of several physical and metabolic factors operating at the blood intimal interface. The polarity of the potential suggests that the interface is negative with respect to the blood flowing through the vessel. Interfacial potential and related V(8) are discussed in terms of their possible importance as a mechanism for maintaining vascular homeostasis in the living animal.

  19. Simultaneous evaluation of brain tumour metabolism, structure and blood volume using [{sup 18}F]-fluoroethyltyrosine (FET) PET/MRI: feasibility, agreement and initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Henriksen, Otto M.; Hansen, Adam E.; Law, Ian [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Clinical Physiology Nuclear Medicine and PET, Copenhagen (Denmark); Larsen, Vibeke A. [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Radiology, Copenhagen (Denmark); Muhic, Aida; Poulsen, Hans S. [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Oncology, Copenhagen (Denmark); Larsson, Henrik B.W. [Copenhagen University Hospital Rigshospitalet Glostrup, Functional Imaging Unit, Department of Clinical Physiology Nuclear Medicine and PET, Glostrup (Denmark)

    2016-01-15

    Both [{sup 18}F]-fluoroethyltyrosine (FET) PET and blood volume (BV) MRI supplement routine T1-weighted contrast-enhanced MRI in gliomas, but whether the two modalities provide identical or complementary information is unresolved. The aims of the study were to investigate the feasibility of simultaneous structural MRI, BV MRI and FET PET of gliomas using an integrated PET/MRI scanner and to assess the spatial and quantitative agreement in tumour imaging between BV MRI and FET PET. A total of 32 glioma patients underwent a 20-min static simultaneous PET/MRI acquisition on a Siemens mMR system 20 min after injection of 200 MBq FET. The MRI protocol included standard structural MRI and dynamic susceptibility contrast (DSC) imaging for BV measurements. Maximal relative tumour FET uptake (TBR{sub max}) and BV (rBV{sub max}), and Dice coefficients were calculated to assess the quantitative and spatial congruence in the tumour volumes determined by FET PET, BV MRI and contrast-enhanced MRI. FET volume and TBR{sub max} were higher in BV-positive than in BV-negative scans, and both VOL{sub BV} and rBV{sub max} were higher in FET-positive than in FET-negative scans. TBR{sub max} and rBV{sub max} were positively correlated (R{sup 2} = 0.59, p < 0.001). FET and BV positivity were in agreement in only 26 of the 32 patients and in 42 of 63 lesions, and spatial congruence in the tumour volumes as assessed by the Dice coefficients was generally poor with median Dice coefficients exceeding 0.1 in less than half the patients positive on at least one modality for any pair of modalities. In 56 % of the patients susceptibility artefacts in DSC BV maps overlapped the tumour on MRI. The study demonstrated that although tumour volumes determined by BV MRI and FET PET were quantitatively correlated, their spatial congruence in a mixed population of treated glioma patients was generally poor, and the modalities did not provide the same information in this population of patients. Combined

  20. Cerebral blood volume estimation by ferumoxytol-enhanced steady-state MRI at 9.4 T reveals microvascular impact of α1 -adrenergic receptor antibodies.

    Science.gov (United States)

    Pohlmann, Andreas; Karczewski, Peter; Ku, Min-Chi; Dieringer, Babette; Waiczies, Helmar; Wisbrun, Natali; Kox, Stefanie; Palatnik, Irina; Reimann, Henning Matthias; Eichhorn, Christina; Waiczies, Sonia; Hempel, Petra; Lemke, Bernd; Niendorf, Thoralf; Bimmler, Marion

    2014-09-01

    Cerebrovascular abnormality is frequently accompanied by cognitive dysfunctions, such as dementia. Antibodies against the α1 -adrenoceptor (α1 -AR) can be found in patients with Alzheimer's disease with cerebrovascular disease, and have been shown to affect the larger vessels of the brain in rodents. However, the impact of α1 -AR antibodies on the cerebral vasculature remains unclear. In the present study, we established a neuroimaging method to measure the relative cerebral blood volume (rCBV) in small rodents with the ultimate goal to detect changes in blood vessel density and/or vessel size induced by α1 -AR antibodies. For this purpose, mapping of R2 * and R2 was performed using MRI at 9.4 T, before and after the injection of intravascular iron oxide particles (ferumoxytol). The change in the transverse relaxation rates (ΔR2 *, ΔR2 ) showed a significant rCBV decrease in the cerebrum, cortex and hippocampus of rats (except hippocampal ΔR2 ), which was more pronounced for ΔR2 * than for ΔR2 . Immunohistological analyses confirmed that the α1 -AR antibody induced blood vessel deficiencies. Our findings support the hypothesis that α1 -AR antibodies lead to cerebral vessel damage throughout the brain, which can be monitored by MRI-derived rCBV, a non-invasive neuroimaging method. This demonstrates the value of rCBV estimation by ferumoxytol-enhanced MRI at 9.4 T, and further underlines the significance of this antibody in brain diseases involving vasculature impairments, such as dementia.

  1. Near-infrared spectroscopy extended with indocyanine green dye dilution for cerebral blood flow measurement: Median values in healthy volunteers

    Science.gov (United States)

    Mudra, R.; Muroi, C.; Niederer, P.; Keller, E.

    2008-09-01

    The cerebral blood flow (CBF) is an important vital parameter in neurointensive care. Currently, there is no non-invasive method for its measurement that can easily be applied at the bedside. A new tool to determine CBF is based on near-infrared spectroscopy (NIRS) applied together with indocyanine green (ICG) dye dilution. From a bilateral measurement on selected regions on the head of infrared (IR) absorption at various wavelengths during the dilution maneuver, the vascular perfusion characteristics of the two brain hemispheres can be determined in terms of mean transit time (mtt) of ICG, cerebral blood volume (CBV) and CBF. So far, on nine healthy volunteers, NIRS ICG dye dilution bihemispheric measurements were performed, which yielded to mtt given as median (range) of 9.3 s (5.1-16.3 s), CBV of 3.5 ml/100 g (1.7-4.1 ml/100 g), and CBF of 18.2 ml/(100 g×min) [11.1-48.6 ml/(100 g×min)]. Additionally, the blood flow index (BFI) was calculated with BFI= 13.8 mg/(100 g×s) [6.6-15.2 mg/(100 g×s)]. The Spearman rank correlation coefficient between CBF and BFI was RS = 0.76. However, as the Bland & Altman plot between CBFNIRS and the CBFBFI documents, the limits of agreement are rather wide (21.9±6.7). Under physiological conditions in healthy volunteers, no differences could be detected between the hemispheres.

  2. Measurements of blood flow and blood concentration change using laser speckle in fiber illumination and its application to estimation of stress condition

    Science.gov (United States)

    Yokoi, Naomichi; Shinohara, Tomomi; Funamizu, Hideki; Kyoso, Masaki; Shimatani, Yuichi; Yuasa, Tomonori; Aizu, Yoshihisa

    2016-11-01

    Speckle imaging method is useful for monitoring of blood flow in living bodies. We have proposed so far the method for simultaneous imaging of blood flow and blood concentration change using laser speckle patterns at two wavelengths. However, our conventional measurement system has difficulty in adjusting the illuminating optical axis of two laser sources. Therefore, we introduce a novel arrangement using a coaxial fiber illumination in the detection of speckle patterns in two wave