Magnetic susceptibility of Dy-DTPA-BMA to reperfused myocardial infarctionin an excised dog heart model: evidence of viable myocardium

Objective To assess the effects of Dy-DTPA-BMA (sprodiamide) on ex-vivo MR imaging of reperfused acute myocardial infarction. Methods Eighteen dogs were subjected to 2-hour coronary artery occlusion fo llowed by 24-hour reperfusion. Dysprosium-chelate (Dy-DTPA-BMA) was injecte d into 16 dogs. Twenty minutes before their sacrifice. Two dogs did not rec eive the contrast medium and were used as controls. Excised hearts were ima ged on T2-weighted spin-echo sequence (T2W SE) and T2*-weighted gradient re called echo sequence (T2*W GRE), then sectioned and double-perfused for pla nimetric comparison. Results Dy-DTPA-BMA induced myocardial signal loss was detected on T2W SE a nd on T2*W GRE images. The signal loss was observed at the subendocardial l ocation of the myocardial wall inducing an apparent enlargement of the left ventricle cavity and a thinning appearance of the anterior myocardial wall . Conclusions Myocyte necrosis diminishes the potency of dysprosium to cause MR imaging signal intensity loss in reperfused myocardial infarction. Pre-i nfarcted myocardium with potentially reversible viability may be responsibl e for the effect of the contrast medium.