Detection of acute myocardial ischemia using first-pass dynamics of MnDPDPon inversion recovery echoplanar imaging

Previous studies used manganese N,N'-bis-(pyridoxal 5-phosphate)ethylenedia mine-N,N'-diacetic acid (MnDPDP) to detect myocardial ischemia at a dose of 0.4 mmol/kg with spin echo imaging. The purpose of this study was to detec t acute myocardial ischemia using MnDPDP at a dose range near that approved for hepatobiliary imaging (0.005 mmol/kg) in conjunction with inversion re covery echoplanar imaging (nr. EPI), Regional ischemia was produced in 26 r ats by occluding the left coronary artery for 20-30 minutes before imaging. Consecutive 32 IR EP images (inversion time [TI]/TR/TE 700/2000/10 msec) w ere obtained to monitor the first pass of MnDPDP at four incremental doses (0.005, 0.01, 0.02, or 0.04 mmol/kg, n = 6-8), MnDPDP produced dose-depende nt enhancement of left ventricular blood and normal myocardium, but not isc hemic myocardium, Quantitative analysis revealed a difference in signal int ensities (P < 0.05) between normal and ischemic myocardium at the time of p eak enhancement in all groups. However, differential enhancement between no rmal and ischemic myocardium produced clear visual delineation of the ische mic region only at doses greater than or equal to 0.01 mmol/kg. In conclusi on, acute myocardial ischemia can be detected with IR EPI using doses close to the clinically approved dose of MnDPDP. J, Magn, Reson, Imaging 1999:9: 209-214, (C) 1999 Wiley-Liss, Inc.