Diagnostic performance of [¹⁸F]FAPI-04 PET/CT in suspected recurrent hepatocellular carcinoma: prospective comparison with contrast-enhanced CT/MRI.

Abstract

To evaluate the diagnostic performance of [¹⁸F]FAPI-04 PET/CT in differentiating hepatocellular carcinoma (HCC) recurrence from treatment-induced lesions (TILs) after therapy and compare it with contrast-enhanced CT/MRI (Ce-CT/MRI). Patients with suspected HCC recurrence after resection or local-regional therapy, who underwent Ce-CT/MRI and [¹⁸F]FAPI-04 PET/CT, were prospectively enrolled. For each patient or lesion, a three-point-scale (positive, negative, or equivocal) was assigned to Ce-CT/MRI and [¹⁸F]FAPI-04 PET/CT. The diagnostic performances of Ce-CT/MRI, [¹⁸F]FAPI-04 PET/CT, and their combination were compared by McNemar's test, with histopathology or radiographic follow-up as a reference standard. The maximum standardized uptake value (SUV_max) and lesion-to-background ratio (LBR) of lesions derived from [¹⁸F]FAPI-04 PET/CT were analyzed, and the cut-off points for distinguishing between HCC recurrence and TILs were calculated. A total of 44 patients with 129 lesions were analyzed, of which 31 patients (91 lesions) were proved to be recurrent HCC and 38 lesions were TILs. On lesion-based analysis, the combination of [¹⁸F]FAPI-04 PET/CT with Ce-CT/MRI demonstrated superior sensitivity (86.8% vs. 70.3% vs. 72.5%), specificity (89.5% vs. 42.1% vs. 52.6%), and accuracy (87.6% vs. 62.0% vs. 66.7%) compared to Ce-CT/MRI and [¹⁸F]FAPI-04 PET/CT alone (all P < 0.001). The combination altered therapy management in 22.7% of patients. On semiquantitative analysis, the SUV_max and LBR of [¹⁸F]FAPI-04 PET in HCC recurrence (n = 91) were significantly higher than those in TILs (n = 38) (SUV_max: 8.1 vs. 3.65, P < 0.001; LBR: 5.4 vs. 1.9, P < 0.001). Using cutoff points of 5.1 for SUV_max and 2.3 for LBR, [¹⁸F]FAPI-04 PET/CT exhibited high sensitivity and specificity in differentiating recurrent HCC from TILs, with 83.5%, 78.9% and 96.2%, 63.2%, respectively. The combination of [¹⁸F]FAPI-04 PET/CT with Ce-CT/MRI significantly improved diagnostic sensitivity, specificity, and accuracy in differentiating recurrent HCC from TILs. [¹⁸F]FAPI-04 PET may be a promising imaging modality in detecting recurrent HCC. clinicaltrials.gov: NCT05485792.