Diagnostic significance of fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography in differentiating Edmondson grade II and III hepatocellular carcinoma.

Background: Preoperative prognosis assessment of hepatocellular carcinoma (HCC) is crucial, and pathologic grading is a key prognostic determinant that affects patient prognosis. Therefore, accurate determination of pathological grading before surgical intervention is crucial for optimizing treatment strategies and improving prognostic outcomes.

Aim: To investigate the distinguishing capability of fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG PET/CT)-derived metabolic parameters between Edmondson grade II and III HCC and to assess their correlation with Ki67 expression levels.

Methods: We retrospectively assessed the ¹⁸F-FDG PET/CT imaging datasets from 32 patients with solitary HCC, all of whom had pathological confirmation of their diagnosis. Patients were categorized into Edmondson grade II and III groups according to pathological grading criteria. Comparative analyses were conducted on metabolic parameters, including maximum standardized uptake value (SUV_max), mean standardized uptake value (SUV_mean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), tumor-to-normal background ratio (TNR), and tumor-to-blood pool ratio (TBR), between the groups. Further, correlations between these parameters and Ki67 expression were investigated.

Results: Significant differences were observed in SUV_max, SUV_mean, TLG, TNR, and TBR between Edmondson grade II and III HCC groups (P < 0.05), whereas MTV was not significantly different (P = 0.052). The maximum tumor diameter and Ki67 expression percentage significantly varied between the two groups (P < 0.05). SUV_max yielded the largest area under the receiver operating characteristic curve, measuring 0.853 (95% confidence interval: 0.709-0.997, P = 0.001). Using an optimal SUV_max cut-off of 10.95, the sensitivity and specificity for identifying Edmondson grade III HCC were 66.7% and 100%, respectively. Notably, significant positive correlations were identified in terms of SUV_max, SUV_mean, TNR, TBR, and the percentage of Ki67 expression (P < 0.01). Conversely, MTV, TLG, and maximum tumor diameter exhibited no significant association with Ki67 expression (P > 0.05).

Conclusion: ¹⁸F-FDG PET/CT-derived metabolic parameters, particularly SUV_max, SUV_mean, TNR, TBR, and TLG, are valuable in differentiating Edmondson grade II and III HCC, with SUV_max showing the optimal differential diagnostic efficacy. TLG is a three-dimensional volumetric parameter that holds some differential diagnostic potential, but it fails to display a distinct advantage. Moreover, increased ¹⁸F-FDG uptake and Ki67 expression in tumor tissue correlate with poorer HCC prognoses, emphasizing their potential role in prognostic assessments.