Assessment of Coronary Plaques by 16-Row Multidetector Computed Tomography. Correlation with Intravascular Ultrasound

pp 193-199

Abstract

Background
Atherosclerosis counts for 50% of cardiovascular deaths. Recent studies have demonstrated that certain atheromatous plaques with a lipid core and positive remodeling, known as vulnerable plaques, are more likely to develop plaque disruption, resulting in a coronary event. The early identification of these atheromatous plaques would have an extremely important clinical impact and might help to prevent the further development of an acute coronary syndrome.

Objective

To assess the diagnostic accuracy of coronary angiography with 16-row multidetector computed tomography (16-MCT) for the detection, characterization and quantification of atherosclerotic coronary artery lesions compared to intravascular ultrasound (IVUS).

Material and Methods
Forty five patients eligible to coronary angiography underwent 16-MCT and IVUS. Plaque burden and the characteristics of atheromatous plaques were analyzed in each coronary segment; plaques were classified in soft, fibrous and calcified. The binomial exact method was used to calculate the diagnostic accuracy of 16-MCT to determine the plaque burden and to identify coronary plaques. ROC curves analysis determined the cut-point for each type of plaque, as well as the mean density and the standard deviation expressed in Hounsfield units (HU). The diagnostic accuracy of the method for the diagnosis of coronary stenosis =50% was also assessed.

Results
The sensitivity and specificity of 16-MCT to detect plaque burden were 96.20% and 81.96%, respectively. For the detection of soft, fibrous and calcified plaques, the sensitivity and the specificity were 94.59% and 92.62%, 94.91% and 98.56%, and 93.22% and 95.13%, respectively. Using a cut-point of 85 HU, 16-MCT correctly identified 86% of soft and fibrous plaques, with an area under the ROC curve of 0.96; a cut-point of 196.68 UH resulted in an identification of 93% of calcified and non-calcified plaques, and the area under the ROC curve was 0.98. The sensitivity and specificity of the test for detecting coronary stenosis were 81.58% and 93.86%, respectively.

Conclusion
16-MCT is a promising non-invasive diagnostic tool for the assessment of patients with coronary artery disease, useful for the detection and characterization of the different types of plaques.