Unroofed sinus is categorized into four subtypes. Types I and II represent complete unroofing with or without an LSVC, respectively [1]. Types III and IV are partial unroofing involving the mid-CS (type III) or near the LA appendage and left superior pulmonary vein (type IV) [1]. CT has advantages over echocardiography in detection of this anomaly (illustrated in this case) as well as in precise delineation of defect and associated findings (presence or absence of LSVC). Short axis reconstructions at the level of CS are helpful in diagnosis. Considerations for repair include location of CS defect, presence of LSVC and other abnormalities as well as comorbidity risks [2].
