Dynamic oxygen-17 MRI with adaptive temporal resolution using golden-means-based 3D radial sampling.

Area of Science:

• * Magnetic Resonance Imaging (MRI)
• * Nuclear Magnetic Resonance Spectroscopy
• * Biomedical Engineering

Background:

• * Current MRI techniques face limitations in resolving dynamic physiological processes in the brain.
• * Quantifying cerebral blood flow and blood-brain barrier permeability requires high-resolution imaging methods.

Purpose of the Study:

• * To develop a high-resolution 3D oxygen-17 (¹⁷O) MRI method.
• * To delineate the kinetics of ¹⁷O-enriched water (H₂¹⁷O) in the entire mouse brain.
• * To apply the method for in vivo imaging of H₂¹⁷O kinetics in post-stroke mouse brains.

Main Methods:

• * Utilized a golden-means-based 3D radial sampling scheme for dynamic ¹⁷O signal acquisition.
• * Employed k-space-weighted view sharing with adaptive windowing for image reconstruction.
• * Validated reconstruction parameters through simulation studies.

Main Results:

• * Achieved isotropic 1.21 mm (0.77 mm nominal) resolution in mouse brain at 9.4T.
• * Demonstrated temporal resolution from 3s to 15s, adapting to signal kinetics.
• * Successfully delineated heterogeneous H₂¹⁷O uptake and washout in stroke-affected brains.

Conclusions:

• * Established a 3D ¹⁷O-MRI method for dynamic monitoring with high spatial/temporal resolution.
• * The method enables quantification of cerebral blood flow and blood-brain barrier permeability.
• * Potential applications include measuring oxygen consumption rates in oxygen inhalation studies.