Assessing coronary sinus blood flow in patients with coronary artery disease: A comparison of phase-contrast MR imaging with positron emission tomography

OBJECTIVE. This study was performed to determine whether MR imaging can be used to reliably measure global myocardial blood flow and coronary flow res erve in patients with coronary artery disease as compared with such measure ments obtained by positron emission tomography (PET). SUBJECTS AND METHODS. We measured myocardial blood flow first at baseline a nd then after dipyridamole-induced hyperemia in 20 patients with coronary a rtery disease. Myocardial blood flow as revealed by MR imaging was calculat ed by dividing coronary sinus flow by the left ventricular mass. Coronary f low reserve was calculated by dividing the rate of hyperemic flow by the ra te of baseline flow. RESULTS. Using MR imaging, myocardial blood flow at baseline was 0.73 +/- 0 .23 mL.min(-1).g(-1), and at hyperemia the blood flow was 1.43 +/- 0.37 mL. min(-1). g(-1), yielding an average coronary flow reserve of 1.99 +/- 0.47. Using PET, myocardial blood flow was 0.89 +/- 0.21 mL.min(-1).g(-1) at bas eline and 1.56 +/- 0.42 mL.min(-1).g(-1) at hyperemia, yielding an average coronary flow reserve of 1.77 +/- 0.36. The correlation of myocardial blood flow and coronary flow reserve measurements for these two methods was an r of 0.80 (p < 0.01) and an r of 0.50 (p < 0.05), respectively. CONCLUSION. This study shows that myocardial blood flow measurements obtain ed using MR imaging have a good correlation with corresponding PET measurem ents. Coronary flow reserve measurements obtained using MR imaging had only moderate correlation with PET-obtained measurements. Our results suggest t hat MR imaging flow quantification could potentially be used for measuring global myocardial blood flow in patients in whom interventional treatment f or coronary artery disease is being evaluated.