Increased ¹⁸F-FDG uptake on PET/CT is associated with poor arterial and portal perfusion on multiphase CT

Purpose: To correlate ¹⁸F-FDG uptake on PET/CTwith patterns of arterial and portal perfusion on multi-detector CT (MDCT) in patients with hepatocellular carcinoma (HCC) and to assess the value of variables from PET/CT and MDCT in predicting histological grades and overall survival. Methods: We retrospectively analyzed MDCT and PET/CT of 66 patients with HCC who underwent surgical treatment. Tumor peak standard uptake value (SUV) was divided by themean liver SUV (T/LSUV). Themean tumor Hounsfield unit (HU) to mean liver HU was calculated for arterial (T/LHU-A) and portal phases (T/LHU-P). All patients were divided into three groups: I, T/L_HU-A ≤ and T/_LHU-P 1 II, T/L_HU-A >1 and T/_LHU-P <1 and III, T/L_HU-A 1 and T/_LHU-P ≤1. The relationships between the CT perfusion groups and T/LSUV were assessed. Multivariate logistic regression analyses were performed using clinical and imaging parameters for predicting histological grade. Overall survival curves stratified by T/LSUVand CT perfusion groups were estimated using the Kaplan-Meier method. Results: Statistically significant differences in T/LSUV were noted between groups I and II (2.29 [range 1.74-3.60] vs. 1.20 [range 1.07-1.58], P < 0.001) and groups I and III (2.29 [range 1.74-3.60] vs. 1.30 [range 1.07-1.43], P < 0.001). In multivariate analysis, a T/LSUV cutoff of >1.46 was the only independent predictor of tumor grade, with an odds ratio of 8.462 (95% confidence interval 1.799-39.803). Kaplan-Meier curves showed significant differences in OS according to T/LSUV >1.62, group I perfusion pattern, and T/LSUV >1.62 plus group I perfusion pattern (P = 0.04, P = 0.021, and P = 0.002, respectively). Conclusion: ¹⁸F-FDG PET/CT is not commonly used for detecting HCC due to its limited sensitivity.We found that increased ¹⁸F-FDG uptake is associated with decreased arterial and portal perfusion onMDCT. This can be used to preselect patients whowould benefit the most from PET/CT. Meanwhile, ¹⁸F-FDG uptake remained as the only independent predictor of histological grade, and higher ¹⁸F-FDG uptake and lower perfusion pattern on MDCTwere significantly related to shorter OS.