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) MRI method to delineate the kinetics of O-enriched water (H O) across the entire mouse brain after a bolus injection via the tail vein.

METHODS

The dynamic O 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 signal. Simulation studies were performed to determine the adequate image reconstruction parameters. The established method was applied to delineating the kinetics of intravenously injected H O in vivo in the post-stroke mouse brain.

RESULTS

The proposed dynamic O-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 H O uptake and washout kinetics in stroke-affected mouse brain.

CONCLUSION

The current study demonstrated a 3D O-MRI method for dynamic monitoring of O 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 H O. It can also be used to measure oxygen consumption rate in O-oxygen inhalation studies.