Search

Contains fulltext : 296790.pdf (Publisher’s version ) (Open Access), Non-invasive ultrasound (US) imaging enables the assessment of the properties of superficial blood vessels. Various modes can be used for vascular characteristics analysis, ranging from radiofrequency (RF) data, Doppler- and standard B/M-mode imaging, to more recent ultra-high frequency and ultrafast techniques. The aim of the present work was to provide an overview of the current state-of-the-art non-invasive US technologies and corresponding vascular ageing characteristics from a technological perspective. Following an introduction about the basic concepts of the US technique, the characteristics considered in this review are clustered into: 1) vessel wall structure; 2) dynamic elastic properties, and 3) reactive vessel properties. The overview shows that ultrasound is a versatile, non-invasive, and safe imaging technique that can be adopted for obtaining information about function, structure, and reactivity in superficial arteries. The most suitable setting for a specific application must be selected according to spatial and temporal resolution requirements. The usefulness of standardization in the validation process and performance metric adoption emerges. Computer-based techniques should always be preferred to manual measures, as long as the algorithms and learning procedures are transparent and well described, and the performance leads to better results. Identification of a minimal clinically important difference is a crucial point for drawing conclusions regarding robustness of the techniques and for the translation into practice of any biomarker.

Udgivelsesdato: 2008/4

Udgivelsesdato: 2008/4

In this paper, we investigate the possibility of using the fractal dimension to characterize carotid atheromatous plaques from B-mode ultrasound images. The images were obtained from ten symptomatic and nine symptomatic subjects, Symptomatic subjects included patients with previous history, of cerebral events, whereas asymptomatic ones had no evidence of any cerebral symptoms prior to the time of the investigation, For each subject, a sequence of images was collected corresponding to 2-3 cardiac cycles. The boundary, of the atheromatous plaque was defined by an expert in three different images of each sequence, corresponding to systole, diastole and a random phase of the cardiac cycle. The fractal dimension of each plaque was estimated using a new method, namely the k-th nearest neighbors method. The results showed that the values of the fractal dimension in the symptomatic group were significantly higher than those in the asymptomatic group., Presented at Annual International Conference of the IEEE Engineering in Medicine and Biology Society (23rd) held in Istanbul, Turkey on 25-28 Oct 2001. See also ADM001351 for entire conference on cd-rom.