In this paper we examine the effect of mild stenosis on blood flow, in an irregular axisymmetric artery with oscillating pressure gradient. The Herschel-Bulkley fluid model has been utilized for this study. The combined influence of an asymmetric shape and surface irregularities of constriction has been explored in this computational study. An extensive quantitative analysis has been performed ...

BACKGROUND The aim of this investigation was to determine the effects of diclofenac on cerebral blood flow. Middle cerebral artery blood flow velocity was measured in nine patients with supratentorial tumours. METHODS Using a transcranial Doppler ultrasound, we measured the baseline mean and systolic cerebral blood flow velocity. Measurements were repeated following administration of diclofen...

We propose a cross-correlation-based method to measure blood-flow velocity by using photoacoustic microscopy. Unlike in previous autocorrelation-based methods, the measured flow velocity here is independent of particle size. Thus an absolute flow velocity can be obtained without calibration. We first measured the flow velocity ex vivo, using defibrinated bovine blood. Then flow velocities in ve...

Orthogonal polarization spectroscopy (OPS) is a technique for taking images to finally characterise microcirculation. Current image analysis algorithms have limitations when applied to image sequences obtained from the liver. We developed an automatic analysis tool which enables detection of liver vessels, measurement of vessel diameters, and determination of blood flow velocities with sparse u...

BACKGROUND: CBFV (cerebral blood flow velocity) is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1) CBFV changes are due to sleep-associated processes or 2) time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of s...

Diameter, blood flow velocity and volumic flow of the brachial artery were measured in 36 patients with sustained essential hypertension and compared with 25 normal subjects. Both hypertensives and control subjects were classified according to age into those younger than and those older than 40 years. For the determinations, a pulsed Doppler velocimeter with an adjustable range-gated time syste...

background: the interaction between the blood and the vessel wall is of great clinical interest in studying cardiovascular diseases, the major causes of death in developed countries. objective: to understand the effects of incorporating fluid-structure interaction into the simulation of blood flow through an anatomically realistic model of abdominal aorta and renal arteries reconstructed from c...

Because little is known about spontaneous changes in cerebral blood flow in neonates, a newly developed online Doppler technique was used to insonate continuously the middle cerebral arteries of a group of sick (n = 20) and full term healthy (n = 16) newborn infants for a period of one minute. A total of 290 recordings of epochs each lasting one minute were analysed, and pronounced regular, cyc...

Characteristics of blood-flow velocities were investigated at different sites in two types of coronary artery bypass grafts, sequential saphenous vein grafts (SSVG) and internal mammary artery grafts (IMAG). The latter appear to have the longest life span. The patency rate of the side-to-side anastomosis of the SSVG is better than that of the end-to-side anastomosis. The SSVG was anastomosed to...

AIM To determine if cerebral blood flow velocity increases during all types of neonatal seizure, and whether the effect is due solely to an increase in blood pressure, transmitted to the cerebral circulation when autoregulation is impaired. METHODS Seizures were diagnosed in 11 high risk neonates using cotside 16 channel video-EEG polygraphy. EEG, cerebral blood flow velocity (CBFV) using tra...