Abstract 16854: An Ungated, Rapid Rest/Stress Myocardial Perfusion Protocol is Useful for Detection of Coronary Artery Disease in Patients With Atrial Fibrillation

Introduction: In patients with atrial fibrillation, the diagnostic accuracy of standard, gated stress/rest perfusion cardiovascular magnetic resonance (CMR) for detection of coronary artery (CAD) disease remains uncertain. Here we investigated using instead an ungated approach with no ECG gating with a rapid rest/stress perfusion protocol to determine its accuracy for detection of CAD in this patient population. To overcome the potential issue of peri-infarct ischemia with a rest-first sequence, we gave very little time between rest and stress perfusion scans. Methods: 23 patients with atrial fibrillation (68 ± 13 years, 13 males and 10 females) underwent a very rapid rest/regadenoson stress perfusion imaging protocol and X-Ray angiography in this study. An ungated radial myocardial perfusion sequence was used (TR/TE = 2.2/1.2 msec, 3T, 20 rays/slice, 5 slices after each saturation pulse, ~2х2х8 mm). Rest/stress protocol was performed in the following order: rest image acquisition (0.05 mmol/kg gadoteridol), administration of regadenoson 0.4 mg intravenously (0.4 mg/5 mL) to induce hyperemia, 70 second wait, then stress image acquisition (0.075 mmol/kg gadoteridol). CMR perfusion images were interpreted by a blinded reader as normal or abnormal, without viewing cine or late gadolinium enhanced images, and also evaluated for quality (1 to 5, lowest to highest). Diagnostic accuracy was evaluated by comparison to X-Ray angiography: significant lesions were defined as stenosis >70 % stenosis or functional flow reserve Results: 18 of the scans were negative and 5 were positive by angiography criteria. Sensitivity, specificity and accuracy for detection of CAD were 100%, 89% and 91%, respectively. Average scan time for imaging acquisition was 6.5 ± 4.0 minutes. Average image quality for both rest and stress perfusion images was 3.2 ± 0.9. Conclusions: An ungated myocardial perfusion sequence with rapid rest/regadenoson stress perfusion protocol addresses the concern of lingering hyperemia with regadenoson and problematic gating. This study suggests that assessment of myocardial perfusion with an ungated technique is an approach with high accuracy for detection of significant CAD in patients with atrial fibrillation.