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 (1/MTT). In dogs, MCE correlated well fr = 0.87, p < 0.00001) with microsphere-assessed myocardial blood flow. In the patients, the subendocardial MCE decreased during hyperemia (0.89 ± 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 ± 0.21, p < 0.02). Parameters slope and 1/MTTparalleled MCE. Contrast-enhanced MRI reflects the transmural redistribution of myocardial perfusion during hyperemia. Perfusion abnormalities can be identified most distinctly in subendocardial myocardium.