Noninvasive quantitative measurement of myocardial and whole-body oxygen consumption using MRI: initial results

The purpose of this study was to investigate the feasibility of a noninvasive approach that combines magnetic resonance imaging (MRI) oximetry and flow measurement to obtain the oxygen consumption in the myocardium and in the whole body. Thirteen healthy male volunteers [mean (±S.D.) age: 35±7 years] underwent this MR study, which included myocardial oxygen consumption (MVO2) measurements in 11 subjects and whole-body oxygen consumption (VO2) measurements in 8 subjects. In six subjects, both measurements were obtained. Five subjects had repeated MRI measurements of global MVO2 in order to verify the reproducibility of this approach. The protocol included in vitro blood sample T2–%O2 calibration, coronary sinus (CS) and main pulmonary artery (MPA) T2 and phase contrast flow measurement and left ventricular (LV) mass calculation. Based on Fick's law, a global measurement of LV MVO2 and whole-body VO2 using MRI was feasible. The MVO2 values were 11±3 ml/min per 100 g LV mass. For repeated measurements, differences in MVO2 of 1 ml/min per 100 g LV mass appear detectable. The whole-body VO2 values were 3.8±0.8 ml/min/kg body weight. MRI techniques that combine CS and MPA T2, flow and LV mass measurements to quantify MVO2 and whole-body VO2 noninvasively in healthy subjects appear feasible, based on their correspondence to previously published work.