VASA VASORUM VISUALIZED BY POWER-DOPPLER IN NORMAL AND ARTERIOSCLEROTIC CAROTID ARTERIES

Vasa vasorum and the perfusion of the carotid wall in normal arteries and in arteries with arteriosclerotic plaques was evaluated in-vivo us ing power-Doppler. Two types of arteries were studied using high-resol ution ultrasound. These were arteries with a normal wall (intima, medi a and adventitia clearly separated) and arteries with intima-media thi ckening and plaques without calcification. In 10 normal subjects and i n 10 patients with early plaques vasa vasorum were visualised. On powe r-Doppler they appeared as distinct, glomerular-like perfusion units, regularly placed along the course of normal arteries and at similar di stance (2 to 4 mm from the lumen-wall interface, within the adventitia and periadventitia layers). In arteriosclerotic vessels the distribut ion of vasa vasorum units was more irregular, often concentrated in on e spot with some perfusion units more distant from the lumen (between 2.5 and 5 mm) and their pulsatility was reduced. Flow velocity complex in most vasa vasorum was comparable, in lower scale to the pattern ob served in the carotid lumen without significant differences between no rmal and arteriosclerotic arteries. The average peak systolic flow vel ocity was 15: +/- 4 cm/sec and the average diastolic velocity was 6 +/ - 4 in normal arteries with a median pulsatility index of 1.8 (range 2 .2-1.05); in arteriosclerotic arteries velocities were 13 +/- 4 (peak systolic) and 3 +/- 2 (end diastolic) with a median pulsatility index of 1.71 (range 2.1-1.1). In conclusion a different, apparent distribut ion of vasa vasorum was observed in normal carotids and in carotids wi th arteriosclerotic lesions.