Magnetic resonance imaging of myocardial perfusion in single-vessel coronary artery disease: implications for transmural assessment of myocardial perfusion

The purpose of the study was to investigate the potential of magnetic resonance imaging (MRI) to assess transmural differences in myocardial perfusion. Contrast-enhanced MRI was performed at rest and during hyperemia in a dog model and in 22 patients with single-vessel coronary artery disease. From MR signal intensity-versus-time curves, three perfusion parameters were derived: maximum myocardial contrast enhancement (MCE), slope, and inverse mean transit time (I/MlT)). In dogs, MCE correlated well (r = 0.87, p < 0.00001) with microsphere-assessed myocardial bloodjow. In the patients, the subendocardial MCE decreased during hyperemia (0.89 2 0.18 vs. 0.74 +- 0.15, p < 0.003) and was lower in subendocardium than in subepicardium (0.74 +: 0.15 vs. 0.84 2 0.21, p < 0.02). Parameters slope and I/MlT paralleled MCE. Contrast-enhanced MRI reflects the transmural redistribution of myocardial perjhsion during hyperemia. Perfusion abnormalities can be identiJ5ed most distinctly in subendocardial myocardium.