Abstract 3084: Accuracy of Multidetector CT in Assessing the Degree of Stenosis Caused by Calcified Coronary Artery Plaques
Purpose: Because of beam hardening and blooming artifacts, it is difficult to determine the degree of stenosis caused by calcified CAPs at CCTA. Our goal was to determine how accurate CCTA is in evaluating these lesions.
Method & Materials: Thirty-one patients who had 1 or more calcified CAPs at CCTA underwent cardiac catheterization (cath). CCTAs were reviewed by 2 experienced radiologists blinded as to cath results. CCTAs were performed on 40- and 64-detector row CTs (Philips Medical Systems, Cleveland, OH) and post-processed using Philips Brilliance workstations. The size of the calcified CAPs was graded subjectively as small, moderate, or large. Using post-processing techniques such as segmentation and tracking, we attempted to determine whether the calcified lesions were obstructive (>50% diameter narrowing) or nonobstructive (<50% diameter narrowing). Concordance with cath was then determined.
Results: Calcified CAPS were graded as small at 61 locations, moderate at 22 locations, and large at 43 locations. With small calcified CAPs, CCTA and cath were concordant in 58/61 (95%). CCTA overestimated the degree of stenosis in 2 and underestimated it in 1. With moderate-sized calcified CAPs, CCTA and cath were concordant in 20/22 (91%). CCTA overestimated the degree of stenosis in the other 2. With large calcified CAPs, CCTA and cath were concordant in 29/43 (67%). In all the other 14, CCTA overestimated the degree of stenosis. In detecting obstructive lesions caused by the large calcified CAPs, CCTA sens=100%, spec=44%, PPV=56%, NPV=100%, accuracy=67%.
Conclusion: CCTA accurately predicts the presence of obstructive disease in >90% of small and moderate-sized calcified CAPs. With large calcified CAPs, CTA correctly predicts presence of obstructive disease about 2/3 of the time. When errors occur, they are virtually always due to overestimation of the degree of stenosis.