T1rho Relaxation Time as a Quantitative MRI Biomarker for Fibrosis Severity in Radiation-Induced Liver Disease: An Experimental Study in Rats

Motivation: HCC in China is common, with radiotherapy causing hard-to-diagnose RILD. MR T1rho imaging may help detect fibrosis early. Goal(s): This study aimed to assess T1rho imaging performance in RILD and its ability to detect radiation-induced liver fibrosis in animals. Approach: Thirty-three male Sprague-Dawley rats, including 9 controls and 24 irradiated with 25 Gy, underwent T1rho MR imaging at 2, 8, and 12 weeks post-radiation, with fibrosis assessed by NASH standards. Results: The rats showed a time-dependent increase in liver fibrosis and T1rho values after radiation, confirmed by pathology and significant elevation at each time point compared to baseline. Impact: T1rho MRI shows potential as a non-invasive method for detecting and monitoring liver fibrosis, enhancing early RILD diagnosis and guiding radiotherapy adjustments if validated in human studies.