Quantitative cardiac perfusion: a noninvasive spin-labeling method that exploits coronary vessel geometry.

Abstract

To quantitate myocardial arterial perfusion with a noninvasive magnetic resonance (MR) imaging technique that exploits the geometry of coronary vessel anatomy. MR imaging was performed with a spin-labeling method in six arrested rabbit hearts at 4.7 T. Selective inversion of magnetization in the short-axis imaging section along with all myocardium apical to that section produces signal enhancement from arterial perfusion. A linescan protocol was used for validation of flow enhancement. Flow was quantitated from two images and validated with spin-echo (SE) imaging. Regional perfusion defects were created by means of coronary artery ligation and delineated with gadolinium-enhanced imaging. Linescan estimates of T1 obtained at physiologic flows agreed with model predictions. Flow-induced signal enhancement measured on SE images also agreed with expected values. Finally, perfusion abnormalities created by means of coronary artery ligation were detected. This spin-labeling method provides quantitative estimates of myocardial arterial perfusion in this model and may hold promise for clinical applications.