The value of cardiac CT in the diagnosis of unroofed coronary sinus syndrome

BACKGROUND: Unroofed coronary sinus syndrome (UCSS) is a rare cardiovascular malformation with nonspecific clinical manifestations that easily causes misdiagnosis and missed diagnosis. The aim of this study is to present the different features of UCSS by various CCT (cardiac CT) postprocessing techniques and evaluate the diagnostic advantages of CCT. METHODS: 9 UCSS patients who were diagnosed by imaging and undergone both CCT and transthoracic echocardiography (TTE) were included in this study, and their CCT images were reviewed. The UCSS images were classified by multiplanar reformations, maximum intensity projection, volume rendering and cinematic rendering. The size of CS roof defect was also measured. RESULTS: Only 4 of 9 CCT confirmed UCSS patients were detected by TTE (4/9, 44.4%), the sensitivity of TTE was lower compared to CCT by Fisher’s exact test (P < 0.05). UCSS was classified according to the Kirklin and Barratt Boyes’s method, including 1 case was classified as type I, 4 cases as type II, 1 case as type III, 2 cases as type IV, 1 case as type V (variant type), and TTE was undiagnosed in all type III-V patients. Additionally, CCT showed 12 extra malformations in these patients, only 5 of them were found by TTE (5/12, 41.7%), and TTE missed all extracardiac malformations. The mean size of CS roof defect was 3.04 ± 1.57 cm. CONCLUSIONS: CCT with various postprocessing technologies has excellent value in diagnosing and differentiating subtypes of UCSS, measuring size of coronary sinus defect, describing accompanying cardiovascular abnormalities.