Abstract Background: To evaluate the additional utility of apparent diffusion coefficient measurement to the treatment response al-gorithm of the Liver Imaging Reporting and Data System ver-sion 2018. Aim of Study: For the purpose of assessing therapeutic re-sponse following locoregional hepatocellular carcinoma treatment. Material and Methods: 110 patients with previously treat-ed HCC who underwent liver magnetic resonance imaging (MRI) were included in this retrospective analysis. According to the LR-TR grading system, treated hepatocellular carcinomas were divided into 3 groups: LR-TR nonviable, LR-TR equivo-cal, and LR-TR viable. Two blinded reviewers independently determined the ADCmean measures of the treated lesions. Results: According to both observers, the ADC mean values for viable HCC were 1.04±0.18 and 1.026±0.17 x 10-3mm2/s, non-viable HCC was 1.48±0.19 and 1.47±0.19 x 10-3mm2/s, and equivocal HCC was 1.29±0.18 and 1.29±0.18 x 10-3mm2/s. With respect to viable HCC (r=0.93), non-viable HCC (r=0.805), and equivocal HCC (r=0.98), there was greatsimilarity between the two assessments. Both observers utilized the same ADC mean cut-off value of 1.355 and 1.251 x 10-3mm2/s with (AUC) of 0.8 and 0.92 to distinguish between viable and non-viable HCC. With an AUC of 0.853 and 0.87, the ADC mean cut-off values utilized to distinguish between viable and equivocal HCC were 1.206 and 1.1125 x 10-3 mm2/s, respectively. With AUC values of 0.82 and 0.76, the ADC mean cut-off values utilized to distinguish between non-viable and equivocal HCC were 1.426 and 1.372 x 10-3mm2/s, respectively. Conclusions: The LI-RADS-v2018 TR algorithm may per-form better and be used in clinical settings if ADC measure-ment is included.