Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: flow mediated vasodilation

Sortuj według:

Ogranicz wyniki do:

Estimation of radial artery reactive response using high frequency ultrasound

Nowicki A., Secomski W., Trawiński Z., Lewandowski M., Trots I., Szubielski M., Olszewski R.

Hydroacoustics

2016

Vol. 19

297--306

Background: There is a growing interest in the application of non-invasive clinical tools allowing one to assess the endothelial function, preceding atherosclerosis. The precision in estimating of the artery Flow Mediated Vasodilation (FMD) using standard 10-12 MHz linear array probes does not exceed 0.2 mm, far beyond that required. Methods: We have introduced a wide-band, high frequency 25-30 MHz, Golay encoded wobbling type imaging to measure dilation of the radial artery instead of the brachial one. 18 young volunteers, and 4 volunteers with cardiac events history, were examined. In the second approach 20 MHz linear scanning combined with 20 MHz pulsed Doppler attached to the linear array was used. The radial artery FMD was normalized using shear rate at the radial artery wall. Results and Conclusions: For the “healthy” group, the FMD resulting from reactive hyperemia response was over 20%; while in the “atherosclerotic” group, the FMD was at least twice as small, not exceeding 10%. The shear rate (SR) normalized FMDSR was in the range from 7.8 to 9.9 in arbitrary units, while in patients with minor cardiac history FMDSR was clearly lower, 6.8 to 7.6. The normalized FMDSR of radial artery RARR can be an alternative to the brachial FMD where the precision of measurements is lower and the diameter dilation does not exceed 7-10%.

Detection of early atherosclerotic changes of arterial wall using ultrasound

Poredos P., Kek A.

Biocybernetics and Biomedical Engineering

1998

Vol. 18, no. 1-2

59-67

Methods used for many years for detecting of arterial stenoses and atherosclerosis based on the imaging of the arterial lumens (e.g. angiography) are of the greatest utility for assessing the relation of the presence of arterial disease to clinical outcome. However, the major disadvantage af these methods is their invasive nature and limited sensitivity for the arterial walls imaging and identification af the early stages of the disease. Newer ultrasonographic methods are more useful for assessing the arterial wall morphalogy and vascular dysfunction. B-mode ultrasaund provide quantitative information on arterial wall morphology and enables measurement af thickness of its constituents. There is growing evidence that thickening of the arterial wall intima-media (IMT) is the earliest detectable morphologic change in atherogenesis and that it preceeds the definitive atherosclerotic lesions. Therefore we studied the influence of different risk factors (smoking, diabetes mellitus) on intima-media thickness. Results of our studies showed dose-relationship between the presence and duration of risk factors and IMT af carotid arteries. The strongest predictors of IMT increase were: age, diabetes mellitus and the degree af the systolic blood pressure increase. IMT was also related to the number of atherosclerotic plaques on investigated carotid arteries and significantly increased in patients with peripheral arterial occlusive disease (PAOD). Using ultrasonographic imaging methods in above mentioned groups of subjects we studied also the influence of risk factors of atherosclerosis on flow mediated vasodilation of peripheral arteries. Impaired vasodilation of brachial arteries as a consequence of endothelial dysfunction was demonstrated in diabetics and in PAOD patients. It was shown that reduced vasodilation preceed morphological changes of the arterial wall in atherogenesis. Ultrasonographic assessment of peripheral arteries provides a promising approach to study the natural history of atherosclerosis and for quantifying the dose - response relations between risk factors and extent of the disease.

W pracy przedstawiono metodę opisania budowy ścian tętnic z użyciem techniki ultradźwiękowej. Metoda ta w porównaniu z wcześniej stosowanymi angiograficznymi metodami szacowania światła tętnic ma charakter nieinwazyjny oraz większą czułość w obrazowaniu ścian tętnic, co pozwala na identyfikację wczesnych stanów choroby. Opracowana metoda pozwala na oszacowanie grubości błony środkowej naczynia krwionośnego. Stanowi to najwcześniej wykrywalną zmianę morfologiczną pochodzenia tętniczego, która może poprzedzać uszkodzenie miażdżycowe. Przebadano wpływ różnych czynników ryzyka (palenie tytoniu, cukrzyca) na grubość błony środkowej. Wyniki badań przeprowadzonych w grupie palaczy i cukrzyków pokazały zależność pomiędzy obecnością i czasem trwania czynników ryzyka oraz grubością błony środkowej tętnic szyjnych. Z użyciem metody obrazowania ultrasonograficznego przebadano także wpływ czynników ryzyka związanych z miażdżycą na rozszerzanie się naczyń obwodowych wywołane przepływem oraz na uszkodzenia tętnic powstałe w wyniku tego rozszerzenia.