Comparison of magnetic resonance imaging studies with enzymatic indexes of myocardial necrosis for quantification of myocardial infarct size

Abstract

To evaluate the potential of gadolinium-diethylene triamine pentaacetic acid (DTPA)-enhanced magnetic resonance imaging (MRI) in the quantification of infarct size in patients with a first acute myocardial infarction, 24 patients with a first acute myocardial infarction were studied by electrocardiographic gated MRI at a mean of 4.3 days after the acute event Multislice, singlephase, T1-weighted, spin-echo MRI in the true short-Axis plane was performed 20 minutes after intravenous injection of gadolinium-DTPA (0.15 mmol/kg of body weight). Circumscript myocardial regions of increased signal intensity on gadolinium-DTPA-enhanced images were considered to be infarcted. Infarct size (in g) was determined using Simpson's rule, and was compared with that based on cumulative release of alphahydroxybutyrate 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; p = 0.0001) and peak creatine kinase-MB levels (r = 0.72; p = 0.002). It is concluded that gadolinium-DTPA-enhanced MRI enables accurate quantification of infarct size in patients with a first acute myocardial infarction.