Abstract:
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Purpose: A close correlation between B-mode sonography and the histopathology and surface structure of plaque is rarely seen in vivo with high grade stenoses of the extracranial carotid artery. The goal of this study was to show whether normalized gray scale analysis and surface analysis of the plaque are capable of characterizing the attributes correctly.
Methods and Materials: Optimized B-mode images of 107 carotid endarterectomy specimens were captured and the gray scale median (GSM) calculated. The specimens were classified histologically into three groups: (1) calcium-rich hard plaques, (2) lipid-rich soft plaques, and (3) combined plaques. The surfaces of the plaques were classified as smooth or rough on the basis of standardized reference samples. The endoluminal surface was digitally documented in vitro by video-endoscopy and again classified into the same categories. All the investigation stages were performed by 2 observers at two different points in time.
Results: Evaluation of the gray scale median showed close inter- and intraobserver correlation (p < 0.01, r > 0.8). However, there was only 46% agreement between the GSM and the histopathological findings. In both in vitro angioscopy (Kappa 0.936, p < 0.001) and sonographic evaluation (Kappa 0.842; p < 0.001) there was a high correlation between the observers with regard to the evaluable specimens. In 73 % agreement was observed between the sonographic image and angioscopy.
Conclusion: Normalized gray scale analysis and evaluation of the plaque surface in an in vitro study make possible observer-independent evaluation. The composition of the plaque cannot be visualized with sufficient accuracy by sonographic GSM analysis. This also applies to the correlation between the sonography and the actual surface composition of the plaque.
Werner MD, L,
In Vitro Plaque Analysis at the Carotid Bifurcation by Ultrasound. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3108854.html
