Intravascular ultrasonic imaging: histologic and echographic correlation.

The feasibility of assessing arterial wall characteristics with an intravascular 40 MHz ultrasonic imaging device was determined in vitro. Ten autopsy specimens of human arteries, with and without atherosclerosis, were studied. A close relationship was observed between the histologic section and the corresponding ultrasonic cross-section with regard to the location, maximum plaque thickness and extent of the atherosclerotic lesion along the circumference of the vessel wall. Based on echogenicity of the atherosclerotic lesion, ultrasound could distinguish four basic types of atherosclerotic plaque components: 1. hypoechoic: a reflection of lipid deposits; 2. soft echoes: reflective of fibromuscular tissue; 3. bright echoes: representative of fibrous tissue; 4. bright echoes with shadowing behind the lesion: representative of calcium deposits. It is anticipated that development of such a catheter-tip imaging system combined with recanalisation methods will be of immense benefit for the precise localisation and identification of vessel wall pathology, precise positioning of a recanalisation instrument (laser device, atherectomy catheter) and subsequent use of this recanalisation procedure and for assessing the effect of recanalisation.