Purpose: To establish the intravascular ultrasound (US) morphology of the arterial wall in various segments of the carotid artery and to evaluate atherosclerotic changes correlated with angiographic and in vitro histopathologic findings.
Materials and methods: A total of 67 carotid arteries were imaged with a 3.5-F, 30-MHz intravascular US catheter: Twenty-four arteries were studied in vivo in 22 patients during neuroendovascular interventional procedures, in situ in 10 cadaveric arteries, and in vitro in 33 fresh excised arteries.
Results: In vivo, none of 10 calcifications and five (29%) of 17 intimal thickenings detected at intravascular US were seen at contrast material-enhanced angiography. At intravascular US, the arterial wall morphology was consistently three layered in the internal carotid artery above the bulb, either vaguely three layered or homogeneous in the bulb and in the carotid bifurcation, and homogeneous in the majority of common carotid arteries. The medial-adventitial interface was distinct in 21 (88%) of 24 arteries in vivo. Histopathologic and intravascular US classifications of the plaque agreed for 31 (82%) of the 38 arterial specimens in vitro.
Conclusion: In vivo intravascular US was feasible in carotid arteries with mild atherosclerosis and often revealed intimal thickenings and concentric plaques in angiographically normal segments.