Cardiac Computed Tomography Detected the Hidden Culprit of a Cryptogenic Stroke: A "Cold" Case.

Around 25%-40% of ischemic strokes are cryptogenic, with no identifiable cause despite thorough evaluation. The mechanisms behind cryptogenic strokes are often embolic, frequently originating from occult cardiac sources. An unroofed coronary sinus (UCS), a rare congenital anomaly, involves a partial or complete absence of the coronary sinus roof, leading to a connection between the left atrium and the coronary sinus. This defect can be asymptomatic or present with symptoms such as paradoxical embolism due to shunting. We present the case of a 70-year-old male with prolonged chest pain and a history of neurological symptoms, who was later diagnosed with a UCS (types III and IV) through cardiac computed tomography (CCT). A cardiac bubble test confirmed a right-to-left shunt, which was not detected on transthoracic echocardiography. This case underscores the importance of considering advanced imaging techniques such as CCT in the diagnosis of cryptogenic stroke, as echocardiography may miss defects due to poor visualization of posterior cardiac structures.