Magnetic resonance T-1 rho quantification of human brain at 5.0 T: A pilot study

MR quantitative T1 rho mapping has gained increasing attention due to its capability to study low-frequency motional processes and chemical exchange in biological tissues. At ultra-high fields, the chemical exchange and proton diffusion in biological tissues should be more prominent. In this study, for the first time, we aim to test the feasibility of brain T-1 rho mapping at 5.0 T MR scanner and compare the T-1 rho values estimated using 3.0 T and 5.0 T scanners. Preliminary experimental results show that 5.0 T achieves T-1 rho-weighted images with a higher signal-to-noise ratio than those acquired at 3.0T. The SNR benefit at 5.0 T is more obvious in high-resolution imaging. The T-1 rho quantifications at 5.0 T are: Corpus callosum (67.4 +/- 1.9 ms), Corona radiate (71.5 +/- 1.8 ms), Superior frontal gyrus (67.6 +/- 2.5 ms), Putamen (58.9 +/- 1.2 ms), Centrum semiovale (84.0 +/- 6.3 ms). Statistical analysis results indicate that the T-1 rho values at 5.0 T show no significant difference with those obtained at 3.0 T (all p > 0.05). The interfield agreements in terms of T-1 rho values between 3.0 T and 5.0 T were substantial (all ICCs > 0.7). The coefficients of variation for T-1 rho measurements from 3.0 T to 5.0 T were all less than 6.50% (2.28%-6.32%).