[High-resolution magnetic resonance imaging of carotid atherosclerotic plaque]

Accuracy of MDCT for detection and identification of carotid atherosclerotic plaque in a rabbit model

OBJECTIVE

There is a need for a simple, rapid, and repeatable noninvasive imaging method to accurately assess carotid atherosclerotic plaque. The purpose of this study was to explore the utility of MDCT and carotid artery plaque analysis software for detecting and identifying atherosclerotic plaque in a rabbit model of carotid atherosclerosis.

MATERIALS AND METHODS

Plaques from 14 rabbits and cross-sectional carotid artery specimens were detected, stained, and analyzed. Contrast-enhanced MDCT with application of carotid plaque analysis software was performed. Bland-Altman difference plots were used to assess interclass and intraclass consistency in lipid percentage and fibrous percentage on CT images.

RESULTS

A total of 76 of the 158 samples were true positive for plaque. On the basis of histopathologic examination of the samples, the accuracy, sensitivity, and specificity of CT for detecting plaque were 91.8%, 89.4%, and 94.5%, and the accuracy, sensitivity, and specificity of the software for classifying lipid-rich plaques and fibrous plaques were 90.8%, 90.6%, and 90.9%. Repeated measurements by the same physician showed good repeatability, and measurements by two physicians independently showed good correlation.

CONCLUSION

The results showed that MDCT can be used to detect carotid atherosclerotic plaque and that carotid plaque analysis software can be used to measure the content of plaque composition and determine the nature of plaque.

Rationale and design of dal-PLAQUE: a study assessing efficacy and safety of dalcetrapib on progression or regression of atherosclerosis using magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography/computed tomography

dal-PLAQUE is a placebo-controlled multicenter study designed to assess the effect of dalcetrapib on imaging measures of plaque inflammation and plaque burden. dal-PLAQUE is a multimodality imaging study in the context of the large dal-HEART Program. Decreased high-density lipoprotein cholesterol is linked to increased risk of coronary heart disease (CHD). Dalcetrapib, a compound that increases high-density lipoprotein cholesterol by modulating cholesteryl ester transfer protein, is being studied to assess if it can reduce the progression of atherosclerotic disease and thereby decrease cardiovascular morbidity and mortality. Patients with CHD or CHD-risk equivalents were randomized to receive 600 mg dalcetrapib or placebo daily for 24 months, in addition to conventional lipid-lowering medication and other medications for cardiovascular risk factors. The primary outcomes are the effect of dalcetrapib on 18F-fluorodeoxyglucose positron emission tomography target-to-background ratio after 6 months and magnetic resonance imaging (MRI) plaque burden (wall area, wall thickness, total vessel area, and wall area/total vessel area ratio) after 12 months. Secondary objectives include positron emission tomography target-to-background ratio at 3 months and MRI plaque burden at 6 and 24 months; plaque composition at 6, 12, and 24 months; and aortic compliance at 6 months. A tertiary objective is to examine the dynamic contrast-enhanced MRI parameters of plaque neovascularization. In total, 189 subjects entered screening, and 130 were randomized. dal-PLAQUE will provide important information on the effects of dalcetrapib on markers of inflammation and atherosclerotic plaque burden and, thereby, on the safety of cholesteryl ester transfer protein modulation with dalcetrapib. Results are expected in 2011.