Volumetric assessment of plaque progression with 3-dimensional ultrasonography under statin therapy.

BACKGROUND AND PURPOSE: Lowering of serum cholesterol levels with HMG-CoA reductase inhibitors (statins) slowed the progression of atherosclerosis in the carotid arteries in several clinical trials using carotid artery intima media thickness as primary outcome measure. Whereas conventional ultrasonography is limited to thin 2-dimensional image planes, 3-dimensional (3D) ultrasonography provides quantitative measurement of the entire carotid artery plaque volume. This study aims to assess the feasibility of 3D ultrasonography to monitor plaque progression in hypercholesterolemic patients. METHODS: The authors prospectively assessed the progression of 31 carotid artery plaques over 15.1 +/- 4.5 months in a study of 23 patients (6 women, 17 men; mean age = 61.7 +/- 7.5 years) with hypercholesterolemia under therapy with HMG-CoA reductase inhibitors. All patients were maintained on a lipid-lowering diet. Sixteen patients were additionally treated with statins. Quantitative measurements of carotid artery plaque volumes were performed after 3D reconstruction of exactly parallel transverse duplex ultrasound scans (slice distance = 0.1 mm) into volumetric 3D data sets and segmentation of voxels representing the carotid artery plaque. RESULTS: Within the treatment group, plaques were significantly less frequently progressive if they had a hypoechoic echogenicity (11%, n = 9 vs 64%, n = 14; P = .016) or if baseline serum cholesterol levels were above 8.0 mmol/L (9%, n = 11 vs 75%, n = 12; P = .002). CONCLUSION: Three-dimensional ultrasonography extends the measurement of the arterial wall thickness to the 3D volume of an entire atherosclerotic plaque including analysis of its morphology and configuration. However, further clinical trials with an adequate sample size to achieve sufficient statistical power are necessary to assess the effect of statin therapy on plaque progression.

Three-dimensional ultrasound observation of carotid artery plaque ulceration.

BACKGROUND AND PURPOSE: Carotid artery plaque ulceration is associated with an increased risk of cerebral embolism. However, because of the rather poor diagnostic quality of conventional 2-D ultrasound and angiography compared with the evaluation of pathological specimens, little information exists on the natural course of carotid plaque ulceration. Recently, the introduction of 3-D ultrasound has made reproducible investigation of plaque morphology possible, providing a reliable plaque surface analysis. METHODS: We performed 3-D ultrasound examinations of 17 carotid artery plaques with an ulcerated surface in a prospective study of 16 patients (10 men, 6 women; mean+/-SD age 68.9+/-7.1 years) over a mean observation period of 17.6+/-6.3 months. Exactly parallel B-mode ultrasound scans (slice distance 0.1 mm) were acquired with a 5-MHz linear array probe clamped in a carriage device and driven by a mechanical step motor. The recorded images were reconstructed into a volumetric data set in a Cartesian coordinate system. RESULTS: At the end of the observation period, surface configuration had changed in 4 cases (23.5%). Plaque ulceration regressed in 3 cases, whereas ulcer progression occurred in 1 case. The remaining 13 plaques (76. 5%) showed an unchanged surface configuration. CONCLUSIONS: Through the use of 3-D ultrasound, it is possible to noninvasively examine the regression and progression of carotid artery plaque ulceration.