Kinetic characterization of CMD-A2-Gd-DOTA as an intravascular contrast agent for myocardial perfusion measurement with MRI

Recent developments in magnetic resonance imaging (MRI) using specific cont rast media allow the assessment of myocardial perfusion, The purpose of thi s study was to characterize the intravascular properties of a new macromole cular contrast agent, CMD-A2-Gd-DOTA, to evaluate myocardial perfusion, Two groups of isolated pig hearts perfused at various controlled flows were us ed, To demonstrate the intravascular properties of CMD-A2-Gd-DOTA, the agen t was simultaneously injected with 99mTc-labeled red blood cells in five he arts (group 1), Tracer kinetics of both compounds were assessed by coronary sinus effluent sampling, radioactivity counting and concentration determin ation in samples for first-pass time curves measurements, Five other hearts (group 2) were studied using a two-slice turboFLASH sequence on a 1.5-T wh ole-body MRI in order to evaluate first-pass CMD-A2-Gd-DOTA signal intensit y (SI) versus time curves, In group 1,for the studied flows ranging from 0. 8 to 3.1 ml/min(-1) . g(-1), CMD-A2-Gd-DOTA showed first-pass concentration curves typical of an intravascular contrast agent. In group 2, MRI paramet ers, i.e., upslope and mean transit time of SI time curves correlated stron gly with myocardial perfusion, Within the physiologic range of flows, CMD-A 2-Gd-DOTA was able to demonstrate tracer kinetics for in vivo assessment of myocardial perfusion using MRI, (C) 2000 Wiley-Liss, Inc.