Comparison of MRI-based response criteria and radiomics for the prediction of early response to transarterial radioembolization in patients with hepatocellular carcinoma.

PURPOSE: The purpose of this study was to evaluate the capabilities of radiomics using magnetic resonance imaging (MRI) data in the assessment of treatment response to 90yttrium transarterial radioembolization (TARE) in patients with locally advanced hepatocellular carcinoma (HCC) by comparison with predictions based on European Association for the Study of the Liver (EASL) criteria. PATIENTS AND METHODS: Twenty-two patients with HCC (19 men, 3 women; mean age: 66.7 ± 9.8 [SD]; age range: 37-82 years) who underwent contrast-enhanced MRI 4 ± 1 weeks before and 4 ± 4 weeks after TARE, were enrolled in this retrospective study. Regions of interest were placed manually along the contours of the treated tumor on each axial slice of arterial and portal phase images using the ITK-SNAP post-processing software. For each MRI, the Pyradiomics Python package was used to extract 107 radiomics features on both arterial and portal phases, and resulting delta-features were computed. The Mann-Whitney U test with Bonferroni correction was used to select statistically different features between responders and non-responders (i.e., those with progressive or stable disease) at 6-month follow-up, according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST). Finally, for each selected feature, univariable logistic regression with leave-one-out cross validation procedure was used to perform receiver operating characteristic (ROC) curve analysis and compare radiomics parameters with MRI variables. RESULTS: According to mRECIST, 14 patients (14/22; 64%) were non-responders and 8 (8/22; 36%) were responders. Four radiomics parameters (long run emphasis, minor axis length, surface area, and gray level non-uniformity on arterial phase images) were the only predictors of early response. ROC curve analysis showed that long run emphasis was the best parameter for predicting early response, with 100% sensitivity (95% CI: 68-100) and 100% specificity (95% CI: 78-100). EASL morphologic criteria yielded 75% sensitivity (95% CI: 41-96%) and 93% specificity (95% CI: 69-100%). CONCLUSION: Radiomics allows identify marked differences between responders and non-responders, and could aid in the prediction of early treatment response following TARE in patients with HCC.

18F-choline PET-computed tomography for the prediction of early treatment responses to transarterial radioembolization in patients with hepatocellular carcinoma.

BACKGROUND: Transarterial radioembolization (TARE) is widely used for the treatment of hepatocellular carcinoma (HCC), but early treatment response can be very difficult to assess. The aim was to evaluate 18F-fluorocholine PET/computed tomography (CT) to assess the treatment response in patients with intermediate or locally advanced HCC. METHODS: Between March 2019 and July 2020, nine HCC patients treated with TARE, who underwent PET/CT at baseline and 1 month after treatment, were enrolled. The maximum, mean (SUVmean), and peak (SUVpeak) standardized uptake value (SUV), SUV normalized by lean body mass (SUL), and total lesion glycolysis (TLG) were measured. Statistical analysis used the Mann-Whitney test to evaluate the differences in parameters between responders (partial and complete response) and nonresponders (stable or progressive disease) at the 6-month follow-up, according to the modified Response Evaluation Criteria in Solid Tumors. RESULTS: Three patients were nonresponders (progressive disease and stable disease) and six were responders. Delta SUVmean, delta SUL, and delta TLG could predict an early response (P = 0.02, P = 0.04, and P = 0.02, respectively). None of the pre-therapeutic parameters were correlated with the response. Post-therapeutic SUL, SUVmean, TLG, and SUVpeak were also predictive of the response. CONCLUSIONS: Our preliminary results showed that changes in certain metabolic parameters (from baseline PET to 1-month PET) are predictive of the response to TARE in HCC (Delta SUVmean, delta TLG, and delta SUL). The absence of post-treatment inflammation could lead to a better prediction than MRI evaluation. This study suggests that 1-month 18F-choline PET/CT could modify the clinical management predicting responders.Video Abstract: http://links.lww.com/NMC/A193.