Quantification of myocardial perhsion by MRI after coronary occlusion

Abstract
The objectives of this study were to define the relationship between the first order constant of Gd‐DTPA transfer (K1) and the myocardial blood flow (MBF) at rest and to compare it with an equivalent relationship obtained for positron emission tomography (PET). In a canine model of permanent coronary occlusion (n = 4), myocardial and blood time concentration curves obtained by 13N‐ammonia PET and Gd‐DTPA‐enhanced MRI were fitted by a one‐compartment model to determine K1. A linear relationship was observed between MRIderived K1 and MBF measured by microspheres (K1 = 0.88 × flow −0.015, R = 0.95), which compares favorably with the equivalent relationship derived from PET (K1 = 0.74 × flow +0.16, R = 0.88). The results of this preliminary study suggest that, at rest and distal to a permanently occluded coronary artery, myocardial perfusion quantification by MRI is possible and can challenge PET.