Area-preserving flattening maps of 3D ultrasound carotid arteries images.
ABSTRACT Quantitative measurements of the progression (or regression) of carotid plaque burden are important in monitoring patients and evaluating new treatment options. 3D ultrasound (US) has been used to monitor the progression of carotid artery plaques in symptomatic and asymptomatic patients, and different methods of measuring various ultrasound phenotypes of atherosclerosis have been developed. We have developed a quantitative metric used to analyze changes in carotid plaque morphology from 3D US. This method matched the vertices on the carotid arterial wall surface with those on the luminal surface. Vessel-wall-plus-plaque thickness (VWT) was obtained by computing the distance between each corresponding pair, which was then superimposed on the arterial wall to produce the VWT map. Since the progression of plaque thickness is important in monitoring patients who are at risk for stroke, we also computed the change of VWT by comparing the VWT maps obtained for a patient at two different time points. In this paper, we propose a technique to flatten the 3D VWT and VWT-Change maps in an area-preserving manner, in order to facilitate the visualization and interpretation of these maps.
- New England Journal of Medicine 06/1994; 330(20):1431-8. · 51.66 Impact Factor
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ABSTRACT: 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. 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. 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). 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.Journal of Neuroimaging 08/2002; 12(3):245-51. · 1.41 Impact Factor
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ABSTRACT: Morphological characterization of carotid plaques has been used for risk stratification and evaluation of response to therapy, evaluation of new risk factors, genetic research, and for quantifying effects of new anti-atherosclerotic therapies. We developed a 3D US system that allows detailed studies of carotid plaques in 3D. Our software includes 3D reconstruction, viewing, manual and semi-automated segmentation of carotid plaques, and surface morphology analysis to be used for quantitative tracking of plaque changes. We evaluated our plaque quantification software by examining plaque volume measurement accuracy, variability, and plaque surface morphology. We used vascular test phantoms to study segmentation accuracy, and used 48 3D US carotid plaques of patients ranging in size from 13.2 mm(3) to 544.0 mm(3) to study plaque volume measurement variability. We compared results from the semi-automated plaque measurements to the results obtained from manual measurements, which were used as the "gold" standard. We developed a surface plaque morphology quantification technique based on the segmented plaque surface curvature and used it to analyze plaques. Accuracy of plaque volume measurements for the simulated plaques ranged from 4.2% to 1.5% for volumes ranging from 68.5 mm(3) to 286 mm(3). The variability study showed that coefficients of variation in the measurement of plaque volume decreased with increasing plaque size for both inter- (90.8-3.9%) and intra-observer (70.2-3.1%) measurements over the plaque sizes measured. Surface morphology analysis showed that 1 mm ulceration could be quantified and monitored for changes over time. The automated plaque quantification approach showed a little higher intra-observer variability than the manual technique, and its performance was better for segmenting the wall than the lumen. Our results indicate that our approach is sensitive tool and can be used in studies of plaque progression and regression as it relates to atherosclerosis treatment effects and can be used effectively in longitudinal studies for direct measurement carotid plaque volume.Ultrasonics 01/2007; 44 Suppl 1:e153-7. · 2.03 Impact Factor