Wenlu Dong Longyang Xiao Ziwei Luo Haiyang Yu Lili Wang Yuanxiang Gao Zhiming Li ^*

• The Affiliated Hospital of Qingdao University, Qingdao, China

Objectives: To assess the diagnostic performance of intravoxel incoherent motion (IVIM) MRI and T1 mapping in detecting hypoxia status of chronic liver disease using a carbon tetrachloride (CCl4)–induced rat model. Materials and Methods: The hypoxia group of chronic liver disease consisted of 8 rats induced by injection of CCl4 and the control group consisted of 9 rats injected with pure olive oil. All 17 rats underwent MRI examination at the time point of 13th week after injection, using T1mapping and IVIM. Liver specimens were subjected to immunohistochemical staining for the exogenous hypoxia marker pimonidazole and the endogenous hypoxia marker HIF-1α, and scored semi-quantitatively. Differences in MRI multi-parameters, Pimonidazole H-scores and HIF-1α were analyzed between control and hypoxia groups. Correlations between MRI multi-parameters and H-score, MRI multi-parameters and HIF-1α were analyzed, and the diagnostic performance of multi-parameter MRI was evaluated by receiver operating characteristic (ROC) curve analysis. Results：There were significant differences between control group and hypoxia group in D* values (p = 0.01) and f values (p = 0.025) of IVIM parameters, T1 mapping (p = 0.003), HIF-1α (p<0.001) and pimonidazole scores (p = 0.004). D* (r = 0.508, p = 0.037) and T1 mapping (r = 0.489, p = 0.046) values showed a positive correlation with pimonidazole scores. D* (r = 0.556, p = 0.020) and T1 mapping (r = 0.505, p = 0.039) showed a positive correlation with HIF-1α. The optimal cut-off value of T1 mapping was 941.527, and the sensitivity, specificity, and AUC were 87.5%, 77.8%, and 0.889(95%CI 0.734-1), respectively. Conclusion: IVIM and T1 Mapping are promising methods for non-invasive detection of hypoxia status in chronic liver diseases.