Abdominal T₁ relaxation times at 7T

To quantify the T₁ relaxation times at 7T for key abdominal organs and tissues, including the liver, kidney, spleen, and skeletal paraspinal muscles.

T₁ mapping was performed on a 7T whole-body scanner with a parallel transmission (pTx) system in five healthy volunteers. Static pTx (B₁⁺ shimming) was applied to maximize B₁⁺ magnitude in the target region. For each T₁ map, data were collected using eight snapshot gradient-echo inversion recovery sequences during breath holding. Voxel-wise T₁ values were calculated based on DICOM data using exponential model fitting.

Mean abdomen T₁ values and corresponding coefficients of variation across the group were: 1829 ± 60 ms, 3.3% for the kidney cortex; 2619 ± 83 ms, 3.2% for the kidney medulla; 1378 ± 48 ms, 3.5% for the liver; 1954 ± 28 ms, 1.4% for the skeletal paraspinal muscle; 1770 ± 36 ms, 2.0% for the spleen.

In this study, we quantified the T₁ relaxation times at 7T for key abdominal organs and tissues, including the liver, kidney, spleen, and skeletal paraspinal muscle. To achieve this, pTx was applied to mitigate B₁⁺ dropouts in the target regions. The B₁⁺ insensitive snapshot gradient-echo inversion recovery method was utilized to acquire accurate and reproducible T₁ maps.