BACKGROUND & AIMS: Increasing enthusiasm around integrating locoregional therapy with systemic immunotherapy in primary liver cancer underscores the need for non-invasive imaging biomarkers. In this study, we aimed to establish advanced molecular MRI tools for monitoring T-cell responses to cryoablation in murine models, distinguishing between immunologically "hot" and "cold" hepatocellular carcinoma (HCC). METHODS: Immunocompetent 7-10-week-old C57BL/6J and BALB/cJ mice (n = 18 each) received carbon tetrachloride for 12 weeks to induce cirrhosis. Intrinsically immunogenic Hepa1-6 ("hot") and non-immunogenic TiB75 ("cold") cells were orthotopically implanted into C57BL/6 or BALB/c mice, respectively, to generate focal HCC lesions. After one week, animals were randomly assigned to (A) partial cryoablation (pCryo) (1.2 mm cryoprobe, -40 °C) or (B) no treatment (n = 8 per group and tumor type). Gadolinium 160 ( RESULTS: pCryo-treated Hepa1-6 tumors displayed peritumoral ring enhancement on T1-weighted MRI with CONCLUSION: pCryo induced increased T-cell infiltration in Hepa1-6 tumors compared to TiB75 tumors. T1-weighted MRI, following IMPACT AND IMPLICATIONS: This study successfully established reliable MR-based molecular imaging tools to visualize CD8