To the Editor: Coronary artery fistula (CAF),an unusual coronary anomaly, was first described in 1841 and it is defined as the abnormal communication between the coronary artery and the cardiac chamber or the great vessels.[1] Most CAFs are congenital, but acquired forms have been reported.[2] The traditional diagnostic tool for CAFs is conventional coronary angiography (CAG), and the incidence of CAF in patients who underwent CAG is 0.06-0.13％.[3,4] However, CAG is an invasive examination, and the complex configuration of the anomalous vessels and their anatomic relations with the surrounding structures may be obscured on two-dimensional angiography images, which may limit precise evaluation of the prevalence of CAFs by CAG.[5] In recent years, other techniques in cardiologic diagnostic imaging have been developed, such as transthoracic echocardiography, transesophageal echocardiography, magnetic resonance angiography, and multi-slice computed tomography (MSCT).[6] Recently, MSCT has changed coronary diagnostics. MSCT offers great spatial resolution with the possibility of performing curved multiplanar reconstructions, maximum intensity projections (MIPs), and volume rendering (VR). The complex coronary anatomy can be readily visualized with MSCT.[7] To date, few reports focused on the value of MSCT evaluation of CAFs. This study aimed to evaluate the prevalence, morphological features, and classification of CAF detected on MSCT in patients from a single Chinese tertiary referral medical center.