Coronary artery stenosis: detection with contrast-enhanced MR imaging in dogs.

Abstract

PURPOSE: To monitor with fast gradient-echo magnetic resonance (MR) imaging the dynamics of gadolinium benzyloxypropionictetraacetate (gadobenate) dimeglumine on myocardial signal intensity in dogs with critical left circumflex coronary artery stenosis. MATERIALS AND METHODS: Fast gradient-echo MR images were acquired in a short axis of the left ventricle. Two bolus injections of 0.05 mmol/kg gadobenate dimeglumine were administered in the basal state after stenosis and after infusion of 0.5 mg/kg dipyridamole. RESULTS: In the basal state, there was an equivalent increase in signal intensity of normal and hypoperfused myocardium during the first pass. Dipyridamole increased left anterior descending flow (287% +/- 36; P < .05) and decreased left circumflex flow (65% +/- 14; P < .05). The magnitude of signal intensity increase during the second bolus in the hypoperfused region was less than that of normal myocardium (P < .05). Contrast-enhanced images showed the hypoperfused region as smaller than the postmortem measurement (43.8% +/- 3.3; P < .05). CONCLUSION: Contrast-enhanced fast MR imaging in the vasodilated state allows detection of hypoperfused myocardium in the presence of critical coronary stenosis.