SONOGRAPHIC ASSESSMENT OF CAROTID-ARTERY STENOSIS - COMPARISON OF POWER DOPPLER IMAGING AND COLOR DOPPLER FLOW IMAGING

Background and Purpose Power Doppler imaging (PDI) is a new ultrasound technique that, in contrast to color Doppler flow imaging (CDFI), gen erates intravascular color signals from the reflected echo amplitude d epending mainly on the density of red blood cells. We evaluated the di agnostic significance of PDI compared with CDFI for the measurement of carotid stenosis and characterization of plaque surface. Methods In 2 5 internal carotid artery stenoses, reduction of the intrastenotic lum en contrasted by blood density signals and color Doppler signals on lo ngitudinal and transverse views was assessed for correlative evaluatio n. In addition, the peak systolic flow velocity of the Doppler spectru m was correlated with PDI and CDFI measurements. Results PDI provided good visualization of the residual lumen in all stenoses, whereas disp lays on CDFI were inadequate in two calcified plaques. PDI revealed tw o ulcerative stenoses classified as smooth on CDFI. The correlation be tween PDI and CDFI was high for measurement of area stenosis (r=.93) a nd moderate for diameter stenosis (r=.73). Similarly, cross-sectional reduction on both imaging methods correlated more significantly with p eak systolic flow velocity than diameter reduction. Conclusions This p ilot study suggests that PDI provides additional information for lumin al measurement and characterization of plaque surface in complicated h igh-grade carotid stenosis. Because of the absent visualization of hem odynamics, PDI should be used in combination with CDFI.