Ultra–High–In-Plane–Resolution 2D T2-Weighted Imaging at 5T Compared to 3T: Visualization of Enlarged Perivascular Spaces
Author Block: J. Lu1, X. Zhang1, Y. Wang2, R. Tang2, B. Zhang1; 1Nanjing/CN, 2Shanghai/CN
Purpose: To compare PVS visualization and quantification between 3T and 5T ultra–high in-plane resolution 2D T2-weighted imaging, and to examine associations with glymphatic-related diffusion and volumetric metrics, as well as behavioral measures.
Methods or Background: From September 2025 to May 2025, 36 healthy adults (mean age ± SD, 26.6 ± 3.3 years; 12 men) underwent same-day 3T and 5T brain MRI, including 2D T2-weighted imaging, 3D T1-weighted imaging, and multi-shell diffusion prospectively. PVS were segmented from Enhanced PVS Contrast images, and five morphological metrics (volume, volume fraction [VF], diameter, solidity, length) were extracted for whole brain, basal ganglia, and hemispheric regions. Associations with free water fraction (FWF), ALPS index, choroid plexus volume (CPV), and clinical scales (HAMA, BMI, PSQI) were evaluated. Paired t-tests and interaction models were applied.
Results or Findings: Median qualitative PVS visualization scores were higher at 5T versus 3T (5.0 vs 3.0, P<.001). Quantitatively, 5T imaging yielded increases of 49.5% in PVS volume, 37.2% in VF, 5.6% in diameter, 14.5% in solidity, and 14.5% in length (all P<.001). 5T-derived PVS metrics showed stronger associations with FWF, ALPS index, and CPV (R² up to 0.41) than 3T (R² < .01), with significant field strength interactions (P = .032). Only 5T detected significant correlations between PVS morphology and behavioral measures, including HAMA, BMI, and PSQI.
Conclusion: 5T MRI substantially improves PVS visualization and quantification compared with 3T, enabling stronger detection of structural–functional coupling and behavioral associations relevant to glymphatic function.
Limitations: This study is limited by its focus on healthy young adults, the limited availability of 5T MRI systems, and its cross-sectional design, which precludes causal inference. These factors may restrict generalizability and immediate clinical translation.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: the institutional review board of Nanjing Drum Tower Hospital