Combined Coronary CT Angiography With Plain Scan for Diagnosis of Ruptured Plaque: Comparison With Optical Coherence Tomography 

Abstract Purpose: To explore the diagnostic efficacy of CCTA + plain scan for ruptured plaques with optical coherence tomography (OCT) as the reference, and to preliminarily analyze the influential factors. Methods: Patients who underwent CCTA and OCT were retrospectively enrolled. Signs of ruptured plaque (plaque ulcer or intra-plaque dye penetration) and other plaque measurements on CCTA were recorded and compared with plain scans (calcification scoring scan) to differentiate calcifications from rupture signs. By OCT, presence of ruptured plaque was determined. Total 65 patients with 71 plaques were included. Results: 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, vs. 0.98±0.26 mm in 27 true positive ruptured plaques (P<0.01).Conclusion: CCTA + plain scan has high specificity and positive predictive value in diagnosing ruptured plaque with medium sensitivity and negative predictive value. The cavity depth of ruptured plaques and calcifications at the rupture site may be the main influential factors.