Dobutamine stress MRI for the assessment of coronary artery disease: expanding our field of view.

tolic function will improve after coronary revascularization (viability testing) [3]. In general, stress CMR is frequently performed with one of two protocols. The more commonly used protocol is myocardial perfusion imaging, which involves intravenous administration of a vasodilator (i.e., adenosine). Stress perfusion CMR allows the evaluation of resting LV contraction as well as detection of myocardial perfusion defects (at rest and after vasodilator stress) following the administration of gadolinium-based contrast media. Delayed enhancement imaging performed several minutes after administration of contrast allows assessment of myocardial tissue for the presence of myocardial scar or edema. An alternative protocol is dobutaminebased stress CMR, involving functional assessment of the LV. Dobutamine stress CMR is performed with increasing doses of intravenous dobutamine (and atropine) to evaluate LV contraction for regional wall motion abnormalities indicative of ischemia or infarction. DSMR4 is performed in a similar protocol to dobutamine stress echocardiography, and the CMR pulse sequence (steady-state free precession) commonly utilized for generating cine images during DSMR does not require the administration of contrast media. In this issue of IMAJ, Hamdan et al. [4] report their initial clinical experience with DSMR in Israel. The authors performed DSMR in 30 patients with suspected or known CAD using a 1.5 Tesla scanner. Reported indications were: evaluation of myocardial ischemia, preoperative assessment and viability testing. The authors employed a standard dobutamine/atro-