This paper describes the design and construction of two ultrasonic Doppler transducers using Finite Element Analysis for blood flow measurement. These transducers were constructed using as sensing element, commercial 8 MHz PIC255 piezoceramic discs, EPO-TEK 301 and Rexolite 4422 as backing and matching layer materials respectively. The objective of this work was to design and construct two sing...

PURPOSE Experiments were undertaken to use a new technique for direct on-line measurement of blood flow in the long posterior ciliary artery (LPCA) in cats and to evaluate possible physiological mechanisms controlling blood flow in the vascular beds perfused by this artery. METHODS Blood flow in the temporal LPCA was measured on a continuous basis using ultrasonic flowmetry in anesthetized ca...

OBJECTIVE: To evaluate the agreement between Doppler ultrasonography and magnetic resonance imaging as well as the interobserver reproducibility of both methods in the measurement of portal blood flow in schistosomal patients. MATERIALS AND METHODS: A cross-sectional, observational, self-paired study evaluated 21 patients with schistosomiasis mansoni submitted to measurement of portal blood flo...

• Measurement of blood flow to the individual gastrointestinal organs has been hampered by limitations of methodology. The oldest and most direct experimental technique for estimating blood flow to an organ is timed collection of its total venous outflow. Traumatic surgical procedures are required to accomplish such collections from the stomach, intestine, or colon. This method is not applicabl...

OBJECTIVES This study sought to validate a new method for direct volumetric blood flow measurement in coronary arteries in animals and in conscious humans during cardiac catheterization. BACKGROUND Direct volumetric measurement of blood flow in selective coronary arteries would be useful for studying the coronary circulation. METHODS Based on the principle of thermodilution with continuous ...

A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow...

We introduce, validate and demonstrate a new software correlator for high-speed measurement of blood flow in deep tissues based on diffuse correlation spectroscopy (DCS). The software correlator scheme employs standard PC-based data acquisition boards to measure temporal intensity autocorrelation functions continuously at 50 - 100 Hz, the fastest blood flow measurements reported with DCS to dat...

Wearable wireless physiological sensors are helpful for monitoring and maintaining human health. Blood flow contains abundant physiological information but it is hard to measure blood flow during exercise using conventional blood flowmeters because of their size, weight, and use of optic fibers. To resolve these disadvantages, we previously developed a micro integrated laser Doppler blood flowm...

background: pulse wave velocity (pwv) is widely used for estimating the stiffness of an artery. v arious invasive and non-invasive methods have been developed to determine pwv over the years. in the present research , the non-invasive estimation of the pwv of large arteries was used as an index for arterial stiffness. methods: a dynamic model based on the navier-stokes equations coupled to elas...