Strain-Encoded Cardiac MR During High-Dose Dobutamine Stress Testing: Comparison to Cine Imaging and to Myocardial Tagging

Purpose: To investigate regional strain response during high-dose dobutamine stress cardiac magnetic resonance imaging (DS-CMR) using myocardial tagging and Strain-Encoded MR (SENC). Materials and Methods: Stress induced ischemia was assessed by wall motion analysis. by tagged CMR and by SENC in 65 patients with suspected or known CAD who underwent DS-CMR in a clinical 1.5 Tesla scanner. Coronary angiography deemed as the standard reference for the presence or absence of CAD (>= 50% diameter stenosis) in all patients. Results: SENC and conventional tagging detected abnormal strain response in six and five additional patients, respectively, who were missed by cine images and proved to have CAD by angiography (P < 0.05 for SENC versus cine, P = 0.06 for tagging versus cine and p = NS for SENC versus tagging). On a per-vessel level, wall motion analysis on cine images showed high specificity (95%) but moderate sensitivity (70%) for the detection of CAD. Tagging and SENC yielded significantly higher sensitivity of 81% and 89%, respectively (P < 0.05 for tagging and P < 0.01 for SENC versus wall motion analysis, and p = NS for SENC versus tagging), while specificity was equally high (96% and 94%, respectively, P = NS for all). Conclusion: Both the direct color-coded Visualization of strain on CMR images and the generation of additional visual markers within the myocardium with tagged CMR represent useful adjuncts for DS-CMR, which may provide incremental value for the detection of CAD in humans.