ULTRAFAST 3-DIMENSIONAL ULTRASOUND - APPLICATION TO CAROTID-ARTERY IMAGING

Background and Purpose-Three-dimensional (3-D) vascular ultrasound can be expected to improve qualitative evaluation of vessel pathology and to provide quantitative data on vascular morphology and function. The objective of this study was to develop an ultrafast 3-D vascular syst em and to validate its performance for quantitation of atherosclerosis and assessment of regional arterial distensibility. Methods-The quant itative analysis of focal atherosclerotic lesions was validated in vit ro on 27 phantoms of fibroadipous plaques of known volume (range, 100 to 600 mm(3)). In vivo reproducibility of plaque volume measurement wa s tested in 33 patients who had a total of 47 predominantly fibroadipo us carotid plaques. Distensibility assessment was validated indirectly through the evaluation of age-related changes in distensibility of co mmon carotid artery in healthy and hypertensive subjects (25 men in ea ch group). Results-The volume of plaque phantoms measured from the 3-D data set showed a very close correlation with the true volume (r=0.99 ; y=0.96x+12.38; P<0.01), with the mean difference between the 2 measu rements being -3.12+/-15.1 mm3. High reproducibility was found for mea surement of carotid plaque volume in vivo: the mean difference between measurements from 2 observers for the same data set was 0.60+/-11.2 m m(3). Indexes of arterial distensibility decreased with age in healthy population, whereas this relationship was lost in hypertensive subjec ts. Conclusions-Ultrafast 3-D ultrasound imaging of carotid artery dem onstrates good accuracy and reproducibility for atherosclerotic plaque volume measurements, The system also allows the study of age-related degenerative vascular changes.