COMPARISON OF MAGNETIC-RESONANCE-IMAGING STUDIES WITH ENZYMATIC INDEXES OF MYOCARDIAL NECROSIS FOR QUANTIFICATION OF MYOCARDIAL INFARCT SIZE

To evaluate the potential of gadolinium-diethylene triamine pentaaceti c acid (DTPA)-enhanced magnetic resonance imaging (MRI) in the quantif ication of infarct size in patients with a first acute myocardial infa rction, 24 patients with a first acute myocardial infarction were stud ied by electrocardiographic gated MRI at a mean of 4.3 days after the acute event. Multislice, single-phase, T1-weighted, spin-echo MRI in t he true short-axis plane was performed 20 minutes after intravenous in jection of gadolinium-DTPA (0.15 mmol/kg of body weight). Circumscript myocardial regions of increased signal intensity on gadolinium-DTPA-e nhanced images were considered to be infarcted. Infarct size (in g) wa s determined using Simpson's rule, and was compared with that based on cumulative release of alpha-hydroxybutyrate dehydrogenase activity in plasma and with peak creatine kinase-MB level in plasma. Infarct size quantified with MRI correlated well with ''enzymatic'' infarct size ( in g equivalents) (y = 0.99x + 0.71; r = 0.93; p0.0001) and peak creat ine kinase-MB levels (r 0.72; p = 0.002). It is concluded that gadolin ium-DTPA-enhanced MRI enables accurate quantification of infarct size in patients with a first acute myocardial infarction.