Dynamic Oxygen-17 Mri With Adaptive Temporal Resolution Using Golden-Means-Based 3d Radial Sampling

Purpose The aim of this study was to develop a high-resolution 3D oxygen-17 (O-17) MRI method to delineate the kinetics of O-17-enriched water ((H2O)-O-17) across the entire mouse brain after a bolus injection via the tail vein.Methods The dynamic O-17 signal was acquired with a golden-means-based 3D radial sampling scheme. To achieve adequate temporal resolution with preserved spatial resolution, a k-space-weighted view sharing strategy was used in image reconstruction with an adaptive window size tailored to the kinetics of the O-17 signal. Simulation studies were performed to determine the adequate image reconstruction parameters. The established method was applied to delineating the kinetics of intravenously injected (H2O)-O-17 in vivo in the post-stroke mouse brain.Results The proposed dynamic O-17-MRI method achieved an isotropic resolution of 1.21 mm (0.77 mm nominal) in mouse brain at 9.4T, with the temporal resolution increased gradually from 3 s at the initial phase of rapid signal increase to 15 s at the steady-state. The high spatial resolution enabled the delineation of the heterogeneous (H2O)-O-17 uptake and washout kinetics in stroke-affected mouse brain.Conclusion The current study demonstrated a 3D O-17-MRI method for dynamic monitoring of O-17 signal changes with high spatial and temporal resolution. The method can be utilized to quantify physiological parameters such as cerebral blood flow and blood-brain barrier permeability by tracking injected (H2O)-O-17. It can also be used to measure oxygen consumption rate in O-17-oxygen inhalation studies.