The use of contrast-enhanced magnetic resonance imaging to identify reversible myocardial dysfunction.

Background: Recent studies indicate that magnetic resonance imaging (MRI) a fter the administration of contrast material can be used to distinguish bet ween reversible and irreversible myocardial ischemic injury regardless of t he extent of wall motion or the age of the infarct. We hypothesized that th e results of contrast-enhanced MRI can be used to predict whether regions o f abnormal ventricular contraction will improve after revascularization in patients with coronary artery disease. Methods: Gadolinium-enhanced MRI was performed in 50 patients with ventricu lar dysfunction before they underwent surgical or percutaneous revasculariz ation. The transmural extent of hyperenhanced regions was postulated to rep resent the transmural extent of nonviable myocardium. The extent of regiona l contractility at the same locations was determined by cine MRI before and after revascularization in 41 patients. Results: Contrast-enhanced MRI showed hyperenhancement of myocardial tissue in 40 of 50 patients before revascularization. In all patients with hypere nhancement the difference in image intensity between hyperenhanced regions and regions without hyperenhancement was more than 6 SD. Before revasculari zation, 804 of the 2093 myocardial segments analyzed (38 percent) had abnor mal contractility, and 694 segments (33 percent) had some areas of hyperenh ancement. In an analysis of all 804 dysfunctional segments, the likelihood of improvement in regional contractility after revascularization decreased progressively as the transmural extent of hyperenhancement before revascula rization increased (P<0.001). For instance, contractility increased in 256 of 329 segments (78 percent) with no hyperenhancement before revascularizat ion, but in only 1 of 58 segments with hyperenhancement of more than 75 per cent of tissue. The percentage of the left ventricle that was both dysfunct ional and not hyperenhanced before revascularization was strongly related t o the degree of improvement in the global mean wall-motion score (P<0.001) and the ejection fraction (P<0.001) after revascularization. Conclusions: Reversible myocardial dysfunction can be identified by contras t-enhanced MRI before coronary revascularization. (N Engl J Med 2000;343:14 45-53.) (C) 2000, Massachusetts Medical Society.