Combined coronary CT angiography with plain scan for diagnosis of ruptured plaque: comparison with optical coherence tomography.

To evaluate the diagnostic efficacy of CCTA + plain scan for ruptured plaques, with optical coherence tomography (OCT) as the reference, and to provide preliminary analysis of influential factors. Patients who underwent CCTA and OCT were retrospectively enrolled. The diagnostic standards for ruptured plaque on CCTA + plain scan were ulcer or intra-plaque dye penetration on CCTA, and a careful review of images from the plain scans to ensure areas of them were not calcification. The diagnosis of ruptured plaque was made by OCT. Total 65 patients with 71 plaques were included. There were 40 OCT-confirmed ruptured plaques in 38 patients and 31 OCT-confirmed non-ruptured plaques in 27 patients. CCTA + plain scan identified 27 ruptured plaques in 27 patients and 28 non-ruptured plaques in 24 patients. With OCT as the gold standard, the per-patient sensitivity, specificity, positive and negative predictive values, and accuracy of CCTA + plain scan for diagnosing ruptured plaque were 71%, 89%, 90%, 69%, and 78%, and there was good agreement (Kappa = 0.70) between CCTA + plain scan and OCT. Among 13 false negative ruptured plaques, 2 had calcifications close to the rupture, and the cavity depth in the remaining 11 was 0.46 ± 0.17 mm, versus 0.98 ± 0.26 mm in 27 true positive ruptured plaques (P < 0.01). CCTA + plain scan may identify morphological features of ruptured plaques. The cavity depth of the ruptured plaques and calcification at the rupture site seem major factors influencing the diagnostic accuracy for plaque rupture. Future perspective studied are needed to confirm these preliminary findings.