Myocardial cell death in reperfused and nonreperfused myocardial infarctions. MR imaging with dysprosioum-DTPA-BMA in the pig.

PURPOSE: To investigate whether Dy-DTPA-BMA-enhanced MR imagining would permit identification of myocardial cell death, myocardial infarction was induced in 12 domestic pigs.
MATERIAL AND METHODS: In 6 pigs with irreversible cell damage, Dy-DTPA-BMA (1.0 mmol/kg b.w.) was administered i.v. 70 min after coronary occlusion. In 6 other pigs, the infarctions were reperfused 80 min after the occlusion, followed by injection of Dy-DTPA-BMA after 30 min of reperfusion. In 4 additional pigs, the hearts were reperfused after 2 min of occlusion. All 16 pigs were sacrificed 10 min after the injection of Dy-DTPA-BMA. The hearts were excised and imaged with MR.
RESULTS: Reversibly injured myocardium could not be distinguished from adjacent nonischaemic myocardium after the administration of Dy-DTPA-BMA. Reperfused, infarcted myocardium demonstrated a high signal intensity in the proton-density- and T2-weighted sequences, despite a 5-fold higher Dy concentration compared with both nonreperfused infarcted and nonischaemic myocardium.
CONCLUSION: This lack of susceptibility effect in infarcted myocardium, due to a homogeneous distribution of Dy, indicates the usefulness of Dy as a marker of tissue viability.