2 research outputs found
Ultrasound-image-based texture variability along the carotid artery wall in asymptomatic subjects with low and high stenosis degrees: unveiling morphological phenomena of the vulnerable tissue
Valid identification of the vulnerable asymptomatic carotid
atherosclerosis remains a crucial clinical issue. In this study, texture
differences were estimated along the atherosclerotic arterial wall,
namely at the plaque, the wall adjacent to it and the plaque shoulder,
i.e. the boundary between wall and plaque, in an attempt to reveal
morphological phenomena, representative of the high stenosis (considered
vulnerable) cases. A total of 25 arteries were interrogated, 11 with low
(50-69%) and 14 with high (70-100%) degrees of stenosis. The two
groups had similar ages. Texture features were estimated from B-mode
ultrasound images, and included four second-order statistical parameters
(contrast, correlation, energy and homogeneity), each calculated at four
different image directions (0 degrees, 45 degrees, 90 degrees, 135
degrees), yielding a total of 16 features. Texture differences between
(a) wall and plaque and (b) wall and plaque shoulder were quantified as
the differences in texture feature values for each tissue area
normalised by the texture feature value of the wall, which was
considered as reference, as illustrated in the following equation:
dTF(i) = (TFi,W - TFi,P/S)/TFi,W, where dTF(i) the estimated texture
difference, TFi,W the texture of the wall, and TFi,P/S the texture of
the plaque (P) or the shoulder (S). Significant differences in texture
variability of wall vs. shoulder were observed between high and low
stenosis cases for 3 features at diastole and 7 features at systole. No
differences were observed for wall vs plaque, although wall texture was
significantly different than plaque texture, in absolute values. These
findings suggest that texture variability along the atherosclerotic
wall, which is indicative of tissue discontinuities, and proneness to
rupture, can be quantitatively described with texture indices and reveal
valuable morphological phenomena of the vulnerable tissue. (C) 2015 The
Authors. Published by Elsevier B.V