ARTICLE ABSTRACTUltrasound-based surveillance has suboptimal sensitivity for early hepatocellular carcinoma (HCC) detection, generating interest in alternative surveillance modalities. We aim to investigate the association between prediagnostic CT or MRI imaging and overall survival in a contemporary cohort of HCC patients. Using the SEER-Medicare database, we analyzed Medicare beneficiaries diagnosed with HCC between 2011 and 2015. Proportion of time covered (PTC) was defined as the proportion of the 36-month period prior to HCC diagnosis in which patients had received abdominal imaging (ultrasound, CT, MRI). Cox proportional hazards regression was used to investigate the association between PTC and overall survival. Among 5,098 HCC patients, 3,293 (65%) patients had abdominal imaging prior to HCC diagnosis, of whom 67% had CT/MRI. Median PTC by any abdominal imaging was 5.6% (IQR: 0%-36%), with few patients having PTC >50%. Compared to no abdominal images, ultrasound (adjusted HR [aHR]: 0.87, 95%CI: 0.79-0.95) and CT/MRI group (aHR: 0.68, 95%CI: 0.63-0.74) were associated with improved survival. Lead time adjusted analysis showed improved survival continued to be observed with CT/MRI imaging (aHR: 0.80, 95%CI: 0.74-0.87) but not ultrasound (aHR: 1.00, 95%CI: 0.91-1.10). Increased PTC was associated with improved survival, with a larger effect size observed with CT/MRI (aHR per 10%: 0.93, 95%CI: 0.91–0.95) than ultrasound (aHR per 10%: 0.96, 95%CI: 0.95-0.98). In conclusion, PTC by abdominal images was associated with improved survival in HCC patients, with potential greater benefit using CT/MRI imaging. Regular utilization of CT/MRI before cancer diagnosis may have potential survival benefit compared to ultrasound in HCC patients.