Three-dimensional power-mode ultrasound for quantification of the progression of carotid artery atherosclerosis

Elucidation of the dynamic nature of plaque progression has important impli cations for clinicians. The present study sought to establish an in vivo me thod for visualizing structural changes in carotid plaques. Three-dimension al reconstruction of parallel two-dimensional gray-scale B-mode ultrasound combined with power-mode examination of 38 carotid artery plaques was perfo rmed in a prospective study of 32 patients (18 men, 14 women; mean age 67.5 +/- 7.6 years). Initial mean plaque volume was 391 mu l. After a mean of 1 8.9 months carotid artery plaque progression had occurred in 15% of carotid artery plaques, with plaque volume increasing 59% in these cases. Plaque v olume remained constant, within a range of +/- 20% in 85% of cases. Progres sive plaques were predominantly hypoechoic (3/5 cases) or had an ulcerated surface in cases of a hyperechoic echogenicity (2/5 cases). Risk factors an d drug therapy were unrelated to plaque progression. This study illustrates that the combination of three-dimensional ultrasound with power-mode imagi ng improves the separation of the intraluminal plaque surface from the vess el lumen. Three-dimensional reconstruction of atherosclerotic carotid arter y plaques enables the reproducible quantification of plaque volume and is t herefore an excellent technique for longitudinal trials assessing progressi on or regression of carotid artery disease.