Depiction of carotid plaque ulceration and other plaque-related disorders by intravascular sonography: a flow chamber study.

PURPOSE To evaluate the ability of intravascular sonography to depict plaque ulceration and to identify the limitations of and the artifacts associated with this technique. METHODS Twenty-eight human carotid arteries were mounted in a pulsatile flow chamber and examined with intravascular sonography. We compared 140 intravascular sonograms with gross pathologic and histologic sections. Ulcerations with a diameter or depth of at least 0.5 mm were sought. RESULTS All eight arteries with ulcerated plaques and nine of 10 individual ulcerations were depicted by intravascular sonography. One artery (one of 140 arterial cross sections) with a small mural thrombus was misinterpreted as ulcerated. Our intravascular sonographic measurements underestimated the gross ulceration dimensions by 22% (depth) and 17% (orifice diameter). CONCLUSIONS Intravascular sonography is highly accurate for the diagnosis of plaque ulceration. The central position of the high-frequency transducer within the target vessel facilitates high resolution of the arterial lumen-wall border, permitting more powerful definition of small ulcerations than available by other diagnostic methods. However, the utility of invasive intravascular sonography for detecting carotid ulcerations cannot be determined until the pathologic significance of plaque ulceration is clearly defined.