Role of 18F-FDG PET/CT and triphasic computed tomography in evaluation of patients with malignant hepatic focal lesions undergoing thermal ablation as local treatment response

Abstract

Background: Hepatocellular carcinoma (HCC) and liver metastases pose significant diagnostic challenges, particularly regarding early detection of extra-hepatic disease and monitoring post-treatment changes. This prospective study compares the diagnostic performance and prognostic utility of 18F-FDG PET/CT versus contrast-enhanced triple-phase computed tomography (CECT) in patients undergoing radiofrequency ablation (RFA) or trans-arterial chemoembolization (TACE). Methods: Eighty-eight patients with laboratory and radiologically confirmed primary HCC or secondary liver metastases were prospectively enrolled. Baseline and sequential follow-up tracking via 18F-FDG PET/CT and CECT were performed to assess extra-hepatic staging, local recurrence, and volumetric/metabolic tumor response parameters in correlation with therapy response and 24-month overall survival (OS). Results: For patients managed with RFA, 18F-FDG PET/CT demonstrated superior diagnostic accuracy for extra-hepatic staging compared to CECT (sensitivity 100% vs. 60%; accuracy 97.78% vs. 79.1%). Similarly, in the TACE cohort, 18F-FDG PET/CT vastly outperformed CECT, which suffered from a high false-positive rate and low sensitivity (PET/CT accuracy 97.78% vs. CECT 68.8%). While no baseline parameters significantly impacted therapy response and survival in the RFA group, baseline tumor size and Total Lesion Glycolysis (TLG) showed a significant moderate negative correlation with 24-month OS in the TACE cohort (P<0.05). Conclusion: Functional 18F-FDG PET/CT provides significantly superior diagnostic accuracy for extra-hepatic metastasis mapping compared to conventional CECT. Furthermore, metabolic parameters like TLG hold vital prognostic value for stratifying overall survival in advanced-stage cohorts undergoing TACE.