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: 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: 0ms, 10 ms, 30 ms, 50ms) in 10 second. Inherent black blood effect of fast spin echo and double inversion recovery were utilized to achieve blood signal suppression. 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 ms (95% limits of agreement: -1.163 to 1.213 ms), and intraclass correlation coefficient (ICC) was 0.977. The scan-rescan reproducibility mean difference was -0.075 ms (95% limits of agreement: -3.280 to 3.310 ms), 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 ms (range: 36.1 - 44.2 ms), which is lower than the value of 42.8=/-2.1 ms 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 parenchyma T1rho value and higher scan rescan reproducibility may improve of the sensitivity of this technique.

💡 Research Summary

The authors present a novel magnetic‑resonance imaging (MRI) technique for liver T1ρ mapping that combines a single‑shot fast spin‑echo (FSE) readout with double‑inversion‑recovery black‑blood preparation. The sequence acquires four spin‑lock times (TSL = 0, 10, 30, 50 ms) simultaneously within a 10‑second breath‑hold, thereby eliminating the need for multiple breath‑holds and reducing motion‑related artifacts that have limited previous bright‑blood gradient‑echo (GRE) approaches. By suppressing blood signal, the method isolates the parenchymal tissue signal, which is expected to yield more accurate T1ρ values.

Nineteen healthy volunteers (10 M/9 F, mean age 37.4 years, range 23–54) were scanned on a 3 T scanner equipped with a dual‑transmitter system. Eleven subjects underwent a repeat scan in the same session to assess intra‑session repeatability, while twelve subjects were rescanned after a 7–10 day interval to evaluate inter‑session reproducibility. T1ρ maps were generated by fitting the signal intensities at the four TSLs to a mono‑exponential decay model using non‑linear least‑squares fitting.

Statistical analysis employed Bland‑Altman plots and intraclass correlation coefficients (ICC). Intra‑session repeatability showed a mean difference of 0.025 ms with 95 % limits of agreement (LoA) of –1.163 to 1.213 ms and an ICC of 0.977, indicating excellent consistency. Inter‑session reproducibility yielded a mean difference of –0.075 ms, LoA of –3.280 to 3.310 ms, and an ICC of 0.820, which surpasses the ICC of 0.764 previously reported for a multi‑breath‑hold bright‑blood GRE technique. The average liver T1ρ measured with the new black‑blood method was 39.9 ± 2.4 ms (range 36.1–44.2 ms), significantly lower than the 42.8 ± 2.1 ms obtained with the bright‑blood approach. The lower value is attributed to the removal of blood‑related signal contamination, allowing a purer assessment of tissue relaxation properties.

The study demonstrates that a single‑breath‑hold black‑blood FSE acquisition provides superior precision and reproducibility for hepatic T1ρ mapping compared with conventional bright‑blood GRE methods. The short acquisition time (10 s) improves patient comfort and fits well into routine clinical workflows. However, the technique currently relies on a 3 T scanner with a dual‑transmitter configuration, and its performance on lower field strengths (e.g., 1.5 T) remains to be tested. Moreover, the validation was limited to healthy subjects; future work should explore the method’s sensitivity to pathological changes such as steatosis, fibrosis, or tumor infiltration, and assess its applicability across multiple sites and scanner platforms. In summary, this work establishes a robust, high‑precision approach for liver T1ρ imaging that could enhance the detection and monitoring of liver disease by providing more reliable quantitative biomarkers.