The contributory role of interstitial water in Gd-DTPA-enhanced MRI in myocardial infarction

We studied the mechanism underlying regional enhancement of myocardial infa rction using T1-weighted IMRI with gadolinium (Gd)-DTPA, Anterior myocardia l infarction (MI) was produced by left anterior descending coronary artery ligation in three groups of rats as follows: 60 minutes occlusion (occlusio n group, N = 6), 60 minutes occlusion plus 120 minutes reperfusion (reperfu sion group, N = 8), and sham-operated (control, N = 6), In Gd-DTPA-enhanced MRI, MI was demarcated as a hypoenhanced region in the occlusion group and as a homogeneous hyperenhanced region in the reperfusion group, Both Gd-DT PA tissue concentration and tissue water content in the anterior wall were highest in the reperfusion group (P < 0.05), a finding suggestive of micros copically observed interstitial edema. The data suggest that regional accum ulation of Gd-DTPA in the reperfused group can be explained by increased in terstitial water content, contributing to the delayed washout of the water- soluble contrast medium. J. Magn, Reson. Imaging 1999;9:215-219, (C) 1999 W iley-Liss, Inc.