ALTERATIONS IN T-1 OF NORMAL AND REPERFUSED INFARCTED MYOCARDIUM AFTER GD-BOPTA VERSUS GD-DTPA ON INVERSION-RECOVERY EPI

This study tested whether Gd-BOPTA/Dimeg or Gd-DTPA exerts greater rel axation enhancement for blood and reperfused infarcted myocardium. Rel axivity of Gd-BOPTA is increased by weak binding to serum albumin, Thi rty-six rats were Subjected to reperfused infarction before contrast ( doses = 0.05, 0.1, and 0.2 mmol/kg). Delta R1 was repeatedly measured over 30 min. Gd-BOPTA caused greater Delta R1 for blood and myocardium than did Gd-DTPA; clearance of both agents from normal and infarcted myocardium was similar to blood clearance; plots of Delta R1 myocardiu m/Delta R1blood showed equilibrium phase contrast distribution, Fracti onal contrast agent distribution volumes were approximately 0.24 for b oth agents in normal myocardium, 0.98 and 1.6 for Gd-DTPA and Gd-BOPTA , respectively, in reperfused infarction, The high value for Gd-BOPTPA was ascribed to greater relaxivity in infarction versus blood. It was concluded that Gd-BOPTA/Dimeg causes a greater Delta R1 than Gd-DTPA in regions which contain serum albumin.