Global myocardial blood flow and global flow reserve measurements by MRI and PET are comparable

Coronary flow reserve (CFR) measurements have been widely used in assessing the functional significance of coronary artery stenosis because they are m ore sensitive in predicting major cardiac events than angiographically dete cted reductions of coronary arteries. Myocardial blood flow can be determin ed by measuring coronary sinus (CS) flow with velocity-encoded cine magneti c resonance imaging (VEC-MRI). The purpose of this study was to compare glo bal myocardial blood flow (MBF) and CPR measured using VEC-MRI with MBF and CPR measured using positron emission tomography (PET). We measured MBF at baseline and after dipyridamole-Induced hyperemia In 12 male volunteers wit h VEC-MRI and PET. With VEC-MRI, MBF was 0.64 +/- 0.09 (ml/min/g) at baseli ne and 1.59 +/- 0.79 (ml/min/g) at hyperemia, which yielded an average CPR of 2.51 +/- 1.29. With PET, MBF was 0.65 +/- 0.20 (ml/min/g) at baseline an d 1.78 +/- 0.72 (ml/min/g) at hyperemia, which yielded an average CPR of 2. 79 +/- 0.97. The correlation of MBFs between these two methods was good (r = 0.82, P < 0.001). The CFRs measured by MRI correlated well with those mea sured using PET (r = 0.76, P < 0.004). These results suggest that MRI Is a useful and accurate method to measure global MBF and CPR. Therefore, it wou ld be suitable for studying risk factor modifications of vascular function at an early stage in healthy volunteers. (C) 2001 Wiley-Liss, Inc.