Relationship between ultrasound texture classification images and histology of atherosclerotic plaque

Structure and content of atherosclerotic plaque varies between patients and may be indicative of their risk for embolisation. This study aimed to cons truct parametric images of B-scan texture and assess their potential for pr edicting plaque morphology. Sequential transverse in vitro scans of 10 caro tid plaques, excised during endarterectomy, were compared with macrohistolo gy maps of plaque content. Multidiscriminant analysis combined the output o f 157 statistical and textural algorithms into five separate texture classe s, displayed as ultrasound (US) texture classification images (UTCI). Visua l comparison between corresponding UTCI and histology maps found the five t exture classes matched with the location of fibrin, elastin, calcium, haemo rrhage or lipid. However, histology preparation removes calcium and lipid a nd, so, can affect the structural integrity of atherosclerotic plaques. Sof t tissue regions smaller than the UTCI kernel, (0.87 mm x 0.85 mm x 3.9 mm) , such as blood clots, are also difficult to detect by UTCI. These factors demonstrate limitations in the use of histology as a "gold standard" for US tissue characterisation. (C) 2001 World Federation for Ultrasound in Medic ine & Biology.