Reproducibility of CMRO2 determination using dynamic 17O MRI

PurposeTo assess the reproducibility of O-17 MRI-based determination of the cerebral metabolic rate of oxygen consumption (CMRO2) in healthy volunteers. To assess the influence of image acquisition and reconstruction parameters on dynamic quantification of functional parameters such as CMRO2. MethodsDynamic O-17 MRI data were simulated and used to investigate influences of temporal resolution (t) and partial volume correction (PVC) on the determination of CMRO2. Three healthy volunteers were examined in two separate examinations. In vivo O-17 MRI measurements were conducted with a nominal spatial resolution of (7.5mm)(3) using a density-adapted radial sequence with golden angle acquisition scheme. In each measurement, 4.00.1L of 70%-enriched O-17 gas were administered using a rebreathing system. Data were corrected with a PVC algorithm, and CMRO2 was determined in gray matter (GM) and white matter (WM) compartments using a three-phase metabolic model (baseline, O-17 inhalation, decay phase). ResultsComparison with the ground truth of simulations revealed improved CMRO2 determination after application of PVC and with t2:00min. Evaluation of in vivo data yields to CMRO2,GM=2.31 +/- 0.1mol/g/min and to CMRO2,WM=0.69 +/- 0.04mol/g/min with coefficients of variation (CoV) of 0.3-5.5% and 4.3-5.0% for intra-volunteer and inter-volunteer data, respectively. ConclusionThis in vivo O-17 inhalation study demonstrated that the proposed experimental setup enables reproducible determination of CMRO2 in healthy volunteers. Magn Reson Med 79:2923-2934, 2018. (c) 2017 International Society for Magnetic Resonance in Medicine.