High-resolution dynamic oxygen-17 MR imaging of mouse brain with golden-ratio-based radial sampling and k-space-weighted image reconstruction

Abstract

Purpose: The current study aimed to develop a three-dimensional (3D) dynamic oxygen-17 (¹⁷ O) MR imaging method with high temporal and spatial resolution to delineate the kinetics of ¹⁷ O water uptake and washout in the brains of mice with glioblastoma (GBM).

Methods: A 3D imaging method with a stack-of-stars golden-ratio-based radial sampling scheme was employed to acquire ¹⁷ O signal in vivo. A k-space-weighted image reconstruction method was used to improve the temporal resolution while preserving spatial resolution. Simulation studies were performed to validate the method. Using this method, the kinetics of ¹⁷ O water uptake and washout in the brains of mice with GBM were delineated after an intravenous bolus injection of ¹⁷ O water.

Results: The proposed ¹⁷ O imaging method achieved an effective temporal resolution of 7.56 s with a nominal voxel size of 5.625 μL in the mouse brain at 9.4 T. Reduced uptake and prolonged washout of ¹⁷ O water were observed in tumor tissue, suggesting compromised cerebral perfusion.

Conclusion: This study demonstrated a promising dynamic ¹⁷ O imaging approach that can delineate ¹⁷ O water kinetics in vivo with high temporal and spatial resolution. It can also be used to image cerebral oxygen consumption rate in oxygen-17 inhalation studies. Magn Reson Med 79:256-263, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Keywords: golden-ratio-based radial sampling; k-space-weighted image contrast reconstruction; oxygen-17 MRI.