Manifestations of 201TI Myocardial Single Photon Emission Computed Tomography in Patients with Coronary Fistula

Background: Coronary fistula is a congenital anomaly resulting in steal phenomenon of coronary blood flow, which may result in clinical symptoms and/or signs of coronary artery disease (CAD), including angina pectoris, myocardial ischemia, and congestive heart failure. The purpose of this study is to do a retrospective analysis of myocardial ischemia in 201TI images in patients with coronary fistulae. Methods: From September, 1992 to December, 2006, 26,758 cases underwent coronary angiography in our hospital and 58 of them (0.22%, 32 male; mean age 62±14, range from 35 to 87 years old), with chest pain and/or chest tightness underwent stress test for CAD. All patients received dipyridamole as pharmacological stress. All patients were followed by image acquisitions done immediately after stress and 4 h later. Results: All patients revealed coronary fistula by coronary angiography. Origin, drainage site, and diameter (large fistula ≥ 10 mm, small fistula ＜ 10 mm) of each fistula were recorded. Fifty seven patients (98%) had 201Tl perfusion defects in either reverse [R], partial reverse [PR], or reverse redistribution [RR] patterns. In the 201TI SPECTs, 82 abnormal perfusion areas were found including 52R (63%), 21PR (26%), and 9RR (11%). In all coronary fistulae, 64% (28/44) in LAD could see 201Tl perfusion defects in anterior, septal, and/or apical areas. In addition, 71% (5/7) in LCX could detect defects in lateral or inferior areas, and 70% (14/20) in RCA could detect defects in inferior and/or lateral areas. In fistulae without 201TI perfusion defect in corresponding territories, micro-fistulae were noted in 81% (13/16) of fistulae in LAD, 100% (3/3) of fistulae in LCX, and 83% (5/6) of fistulae in RCA. Conclusions: Myocardial ischemia with abnormal 201TI perfusion image can be detected in large portion of patients with coronary fistulae. Coronary fistulae with ischemia in 201TI perfusion images also can be associated with chest pain and/or chest tightness. The absence of 201TI perfusion defect in patients with coronary fistula may be due to micro-fistula without evident steal phenomenon of coronary blood flow.