Search results for "DOPPLER"

Color Doppler imaging of the eye and orbit A synopsis of a 400 case experience

2009

Color Doppler imaging (CDI) is a recent advance in ultrasonography that allows simultaneous two-dimensional imaging of structure and blood flow. Doppler information is superimposed in color over a conventional gray-scale ultrasound image. Using this technique we have examined 400 eyes. The central retinal artery, posterior ciliary arteries, ophthalmic artery, the central retinal vein and the vortex veins could be located in all normal eyes. Using the color image as a guide, Doppler spectral analysis is used for quantitative assessment of blood flow velocity in these vessels. We also studied patients with intraocular tumors, arterial and venous retinal occlusions, orbital vascular anomalies …

Laser Doppler Scanning: How Many Measurements are Required to Assess Regional Cerebral Blood Flow?

2000

This study was initiated to determine the optimal number of measuring sites necessary to estimate regional cerebral blood flow (CBF) under pathophysiological conditions.

Microvascular blood flow changes of the abductor pollicis brevis muscle during sustained static exercise

2021

A practical assessment of the general health and microvascular function of the palm muscle, abductor pollicis brevis (APB), is important for the diagnosis of different conditions. In this study, we have developed a protocol and a probe to study microvascular blood flow using near-infrared diffuse correlation spectroscopy (DCS) in APB during and after thumb abduction at 55% of maximum voluntary contraction (MVC). Near-infrared time resolved spectroscopy (TRS) was also used to characterize the baseline optical and hemodynamic properties. Thirteen (n=13) subjects were enrolled and subdivided in low MVC (N=6, MVC<2.3 kg) and high MVC (N=7, MVC≥2.3 kg) groups. After ruling out significant cha…

Variations in acoustical beam properties of intracoronary Doppler catheters.

1993

The limitations of coronary angiography in assessing the functional significance of coronary obstructions is well known. While the critical variable of coronary blood flow cannot be readily measured, intraluminal Doppler sonography offers useful related functional information on blood flow velocity. In order to fully evaluate Doppler signals it is essential to have exact knowledge of the transducer transmission characteristics and of the ultrasound beam topology. In an experimental set-up, the transmitter-receiver characteristics of five commonly used Doppler catheters were investigated. In comparing the beam characteristics we found inhomogeneities in the lateral beam spread. At a penetrat…

Left ventricular non-compaction cardiomyopathy in children: Is segmental fibrosis the cause of tissue Doppler alterations and of EF reduction?

2009

Noncompaction of the ventricular myocardium (LVNC) is a rare congenital cardiomyopathy resulting from an arrest in normal endomyocardial embryogenesis. In 2002 Jenni et al. [Jenni R, Wyss CA, Oechslin EN, Kaufmann PA. Isolated ventricular noncompaction is associated with coronary microcirculatory dysfunction. J Am Coll Cardiol 2002; 39:450-454.] reported a microvascular dysfunction in 12 patients affected by non compaction: areas of restricted myocardial perfusion have been documented by scintigraphy, suggesting a reduction of Coronary flow reserve. McMahon et al reported in a recent article a reduction of TD velocities in children with noncompaction of the left ventricle, compared with nor…

OC005: Ultrasound bioeffects: Quantification of cellular damage in animal fetal liver after use of Doppler pulse to measure ductus venosus

2008

Transposition of the great arteries and aortopulmonary window in the same patient: clinical report and follow-up.

2002

Trasnposition of great arteries (TGA) Has been reported in combination with several congenital defects. Only one case of TGA has been described in association with aortopulmonary window (APW).

Future perspectives in gastroenterology: laser.

1997

Mathematical simulation of Doppler changes in late-onset smallness; progression patterns of cerebral and umbilical anomalies define two types of late…

2019

To evaluate the progression of Doppler abnormalities in fetuses with late-onset fetal smallness (SGA) that become growth restricted (FGR).524 Doppler examinations of the umbilical and cerebral arteries systems, belonging to 442 late-onset SGA fetuses after week 34, were studied, evaluating by means of the statistical difference with the respective abnormal centiles, the pattern of progression into abnormal Doppler values and the distribution and cumulative sum of Doppler anomalies according to the interval to delivery.Only one third (33.5%,Two thirds of late-onset fetal smallness occurs without hemodynamic changes. In half of the remaining cases an initial cerebral vasodilation defines a gr…

Nuevos avances en el conocimiento del síndrome postrombótico

2003

La verdadera incidencia del síndrome postrombótico (SPT) no se conoce con precisión, aunque de la mayor parte de los estudios disponibles, parece deducirse que puede establecerse un año después de la trombosis venosa profunda (TVP) aguda de los miembros inferiores en el 17% al 50% de los pacientes. Inseparablemente unido a la hipertensión venosa que sigue al desarrollo de la incompetencia valvular, se acompaña de una serie de reacciones inflamatorias que incluyen el aumento de la permeabilidad endotelial, la unión de los leucocitos circulantes al endotelio, la infiltración por monocitos, linfocitos y mastocitos del tejido conectivo, y el desarrollo de infiltrados tisulares fibróticos y dist…