Abstract 16969: Plaque Attenuation Pattern Assessment to Predict Advanced Atherosclerotic Lesions in Coronary CT Angiography
Introduction: We sought to determine the accuracy of qualitative assessment of attenuation patterns of non-calcified plaque by CT to differentiate between early and advanced atherosclerotic lesions as defined by histology.
Methods: Overall 611 histological sections from 21 coronary arteries were studied. The coronaries were filled with iodinated methylcellulose and scanned with CT (GE, CT 750HD). Histological sections with an increment of 1.5 mm were prepared and matched with cross-sectional CT images. The images were read randomly for the presence of non-calcified (NP), mixed (MP), calcified plaque (CP). The NCP-s and the non-calcified portion of MP-s were further assessed for the pattern of plaque attenuation and classified as homogenous (HP) or heterogeneous. Plaques that appeared heterogeneous were further stratified into those with and without napkin-ring sign (NRS and non-NRS).
Results: No plaque was detected in 134 (21.9%), NCP in 254 (41.6%), MP in 191 (31.3%), and CP in 32 (5.2%) CT cross-sections. Among NCP components we identified HP in 207 (46.5%), non-NRS plaque in 200 (44.9%) and NRS plaque in 38 (8.6%) cross sections. The absence of plaque had excellent sensitivity and negative predictive value [99.3% (95% CI: 95.9-99.9%) and 99.3% (95% CI: 95.9-100.0%); respectively]. The specificities of NCP and MP to identify advanced lesions were moderate (58.1%, 95% CI: 53.4-62.7% and 71.9%, 95% CI 67.4-76.0%, respectively), similarly to the homogenous and heterogeneous plaques (42.8%, 95% CI: 37.4-48.2% and 57.2%, 95% CI: 51.8-62.6%, respectively). In contrast, the specificity of NRS plaque to identify advanced lesions was excellent (98.9%, 95% CI: 97.4-99.6%). The overall diagnostic performance of the attenuation pattern analysis to identify advanced lesions was better than that of the conventional plaque scheme (area under the curve 0.761 vs. 0.678, respectively; p=0.0012).
Conclusions: The CT finding of NRS is highly specific for the presence of advanced atherosclerotic plaque. The assessment of the plaque attenuation pattern has significantly higher accuracy to identify advanced plaques than the conventional CT plaque scheme. The validity of these findings needs to be demonstrated in vivo.
- © 2011 by American Heart Association, Inc.