Accelerated stress CMR non-inferior to standard protocol, saves 24 minutes per scan

AIMS: In patients with suspected coronary artery disease (CAD), the role of adenosine-stress cardiovascular magnetic resonance (CMR) is well established. However, to meet increasing demand, improving its time efficiency and cost-effectiveness is critical. Recent advances in accelerated, free-breathing cine and scar imaging now enable accelerated stress-perfusion protocols. This study evaluated whether an accelerated, stress-only perfusion protocol achieves non-inferior diagnostic accuracy compared with a standard stress-rest perfusion CMR protocol for detecting significant CAD. METHODS AND RESULTS: Patients with suspected angina referred for invasive coronary angiography (ICA) underwent two 3-Tesla CMR scans (standard and accelerated protocols), on separate days in randomized order. Significant CAD was defined as fractional flow reserve (FFR) ≤ 0.80 in epicardial vessels ≥2 mm diameter (or quantitative flow ratio ≤0.80 if FFR unavailable). CMR images were evaluated qualitatively with (i) primary per-vessel analysis (determined by two independent readers) and (ii) secondary per-patient analysis (following consensus read). Of 167 prospectively recruited patients, 150 completed both CMR protocols and ICA (mean age 66 ± 10 years, 71% male, CAD prevalence 51%). The accelerated scan was better tolerated by patients, with scan duration 19 ± 5 min (24 min shorter than the standard protocol [95% CI: 23, 25], P < 0.001). Compared with standard CMR, accelerated CMR achieved non-inferior per-vessel diagnostic accuracy at a pre-specified 5% non-inferiority margin (+0.7% [-2.7%, 4.0%], pnon-inferiority = 0.001 and +3.4% [-0.1%, 6.8%], pnon-inferiority < 0.001 for the two readers). Accelerated CMR also achieved comparable per-patient accuracy (+4.6% [-1.5%, 11.0%], P = 0.189 for consensus read; accuracy 88.6%, sensitivity 84.2%, and specificity 93.2%). CONCLUSION: Compared to standard stress-perfusion CMR, an accelerated stress-perfusion protocol achieves non-inferior diagnostic accuracy at the vessel level, with a time saving of over 20 min per scan. Accelerated imaging may prove effective in the clinical arena to evaluate patients with suspected angina.