DETECTION AND QUANTIFICATION OF DYSFUNCTIONAL MYOCARDIUM BY MAGNETIC-RESONANCE-IMAGING - A NEW 3-DIMENSIONAL METHOD FOR QUANTITATIVE WALL-THICKENING ANALYSIS

Background Regional left ventricular dysfunction is a major consequenc e of myocardial ischemia, and its extent determines long-term prognosi s. Accurate and reproducible analysis of left ventricular dysfunction is therefore useful for risk stratification and patient management. Me thods and Results Short-axis cardiac cine magnetic resonance (MR) imag ing was performed in 25 patients after anterior myocardial infarction at 21+/-2.1 days after the acute onset. The MR images were analyzed wi th the use of a dedicated analytical software package (MASS version 1. 0), which includes a modified centerline method and a new three-dimens ional analysis approach. A database of 48 healthy volunteers was const ructed to objectively depict myocardial dysfunction in the patients; t his database was compared with enzymatically determined infarct size. The mean (+/-SEM) quantity of dysfunctional myocardium and enzymatical ly calculated infarct size equaled 24.0+/-3.0 and 22.3+/-2.9 g, respec tively (P=.69). Enzymatically determined infarct size correlated stron gly with left ventricular dysfunction determined by cine MR imaging (y =0.90x+3.7; r=.92, P<.0001). Segments related to the distribution of t he left anterior descending coronary artery showed a significantly low er percentage wall thickening in patients than did corresponding segme nts of 48 normal subjects (46.0+/-8.22% versus 87.1+/-3.45%, mean+/-SE M, respectively; P<.001). The mean (+/-SEM) end-diastolic wall thickne ss of the infarcted segment did not differ from that of corresponding normal segments (7.4+/-0.33 versus 7.5+/-0.15 mm; P=.75). Conclusions We conclude that the use of three-dimensional quantitative analysis of cine MR images accurately quantifies the extent of regional left vent ricular dysfunction in the infarcted heart This method of analysis may be useful in assessing the effect of interventional therapies.