Oxygen-enhanced brain MRI using dynamic gradient-echo and MR fingerprinting

OBJECTIVES: Oxygen-enhanced brain magnetic resonance imaging (MRI) using dynamic three-dimensional (3D) gradient-echo and MR fingerprinting (MRF) was applied to evaluate oxygen transit from blood to cerebrospinal fluid (CSF). MATERIALS AND METHODS: Twenty healthy participants, enrolled between December 2023 and March 2024, underwent 3-T MRI including Pre-oxygen inhalation 3D MRF (pre-O₂ MRF), dynamic 3D gradient-echo (volumetric interpolated breath-hold examination, VIBE) during oxygen inhalation, and post-oxygen inhalation 3D MRF (post-O₂ MRF). Pre-O₂ and post-O₂ MRF each consisted of two acquisitions. Signal intensity on dynamic VIBE and T1 relaxation times from MRF were evaluated in gray matter (GM), white matter (WM), surface CSF, and ventricles using volumes of interest (VOIs). RESULTS: Dynamic 3D VIBE demonstrated a rapid signal increase in surface CSF immediately after oxygen inhalation, with a smaller increase in GM. Post-oxygen inhalation VIBE signal was significantly higher than pre-oxygen inhalation signal in surface CSF (p < 0.001) and GM (p < 0.001). T1 relaxation times differed significantly across phases for GM, WM, and surface CSF (p < 0.001) as well as for ventricles (p = 0.024). Large effect sizes were observed for surface CSF (Cohen dz = 4.15) and GM (Cohen dz = 1.31) in dynamic 3D VIBE, as well as for surface CSF (Cohen f = 1.31) and GM (Cohen f = 0.73) in T1 relaxation time measurement, suggesting substantial physiological changes following oxygen inhalation. CONCLUSION: Dynamic 3D VIBE images visualized oxygen inhalation-related signal change in the surface CSF, which were quantitatively validated by T1 relaxation time reductions derived from 3D MRF. KEY POINTS: Question Can noninvasive oxygen-enhanced brain MRI visualize and quantify oxygen-related signal changes in cerebrospinal fluid using dynamic 3D gradient-echo and 3D MR fingerprinting? Findings Dynamic 3D gradient-echo showed rapid surface CSF signal increases after oxygen inhalation, accompanied by significant T1 reductions on 3D MR fingerprinting. Relevance statement This noninvasive oxygen-enhanced MR approach may provide a clinically feasible method for assessing oxygen transit into CSF and could support future investigations of human CSF dynamics. Dynamic 3D gradient-echo images visualized oxygen inhalation-related signal change in the surface CSF, which were quantitatively validated by T1 relaxation time reductions derived from 3D MRF.