Objective To evaluate the diagnostic value of dobutamine stress magnetic resonance imaging (MRI) for myocardial viability. Methods Ten male miniswines underwent left ventriculography and coronary angiography, followed by stenosis of the left circumflex coronary artery (LCX) using ameroid constrictor. More than one month later, left ventriculography and coronary angiography were performed again, followed by cine-MRI at rest and during stress with incremental dose of dobutamine 5-20 μg·kg-1·min-1. Traditional and/or breath-hold cine-MRI were used to evaluate regional left ventricular wall motion, corresponding to basal, midventricular and apical short-axis tomograms. Regional wall motion score index (WMSI) was calculated.The miniswines were finally sacrificed for pathological examination. Triphenyl tetrazolium chloride (TTC) delineated myocardial infarction. Microscopy was used to identify myocardial cellular changes. Results One pig died, one pig suffered from aneurysm and another showed no negative findings. The other seven pigs were found with hypokinetic (n=4) or akinetic (n=3) myocardial regions related to stenosed LCX. Their mean WMSI at rest for the lateral and posteroinferior walls (ischemic regions) of the left ventricle was 2.27±0.32, as compared with 1.00±0.00 (P