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 as- sessed 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 angiogra- phy deemed as the standard reference for the presence or absence of CAD (50% diameter stenosis) in all patients. Results: SENC and conventional tagging detected abnor- mal 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.