Improved liver T1rho measurement precision with a breathhold black blood single shot fast spin echo acquisition: a validation study in healthy volunteers

Purpose: To explore the usability and normal T1rho value of liver parenchyma with a novel single breathhold black blood single shot fast spin echo acquisition based liver imaging sequence. Materials and Methods: The institutional Ethics Committee approved this study. In total 19 health subjects (10 males, 9 females; mean age: 37.4 yrs; range: 23-54 yrs) participated in the study. 11 subjects had liver scanned twice in the same session to access scan-rescan repeatability. 12 subjects had liver scanned twice in two sessions with 7-10 days' interval to access scan-rescan reproducibility. MR was performed with a 3.0 T scanner with dual transmitter. The MR sequence allows simultaneous acquisition of 4 spin lock times (TSLs: 0msec, 10 msec, 30 msec, 50msec) in 10 second, and the spinlock frequency was 500Hz. Inherent black blood effect of fast spin echo and double inversion recovery were utilized to achieve blood signal suppression. Three axial slices were obtained with a resolution of 1.5 × 1.5 × 6.00 mm3. Region-of-interest method was used to measure liver T1 rho value. Results: The technique demonstrated good image quality and minimal artifacts. For liver parenchyma, Bland-Altman plot showed the scan-rescan repeatability mean difference was 0.025 msec (95% limits of agreement: -1.163 to 1.213 msec), and intraclass correlation coefficient (ICC) was 0.977. The scan-rescan reproducibility mean difference was -0.075 msec (95% limits of agreement: -3.280 to 3.310 msec), and ICC was 0.820 which is better than the ICC of 0.764 of a previous bright blood multi-breath hold gradient echo acquisition technique. The liver T1rho value was 39.9 ± 2.4 msec (range: 36.1 44.2 msec), which is lower than the value of 42.8±2.1 msec acquired with the previous bright blood technique. Conclusion: This study validated the application of a single breathhold black blood single shot fast spin echo acquisition based for human liver T1rho imaging. The lower liver