Normal values of high-resolution transmural perfusion distribution metrics for automated quantitative pixel-wise myocardial perfusion cardiovascular magnetic resonance

BACKGROUND: The myocardial blood flow (MBF) transmural distribution between the subendocardial (ENDO) and subepicardial (EPI) layers under resting and hyperemic conditions can aid in the diagnosis of several forms of heart disease. Recently proposed automated in-line myocardial perfusion cardiovascular magnetic resonance (CMR) allows pixel-wise quantification of ENDO- and EPI-MBF, but normal values for these parameters are lacking. We therefore aimed to establish normal values for transmural distribution of MBF in a healthy population. METHODS: ]; stress and rest ENDO-to-EPI gradient [sGRAD and rGRAD]) were computed using the Gadgetron software. RESULTS: (4.0±1.1, 3.9±1.1, 4.0±1.1), sGRAD (1.00±0.13, 0.92±0.09, 1.06±0.18) and rGRAD (1.10±0.09, 1.09±0.07, 1.18±0.11). While there were no sex-specific differences in any of these metrics, all correlated inversely with increasing age. Understanding the MBF dynamics of the myocardial layers in healthy subjects will help to characterize MBF alterations in patients with coronary artery disease or microvascular dysfunction.