Early Dynamic ¹⁸F-FDG PET to Detect Hyperperfusion in Hepatocellular Carcinoma Liver Lesions

Abstract

In addition to angiographic data on vascularity and vascular access, demonstration of hepatocellular carcinoma (HCC) liver nodule hypervascularization is a prerequisite for certain intrahepatic antitumor therapies. Early dynamic (ED) 18 F-FDG PET/ CT could serve this purpose when the current standard method, contrast-enhanced (CE) CT, or other CE morphologic imaging modalities are unsuitable. A recent study showed ED 18 F-FDG PET/CT efficacy in this setting but applied a larger-thanstandard 18 F-FDG activity and an elaborate protocol likely to hinder routine use. We developed a simplified protocol using standard activities and easily generated visual and descriptive or quantitative endpoints. This pilot study assessed the ability of these endpoints to detect HCC hyperperfusion and, thereby, evaluated the suitability in of the protocol everyday practice. Methods: Twenty-seven patients with 34 HCCs (diameter $ 1.5 cm) with hypervascularization on 3-phase CE CT underwent liver ED 18 F-FDG PET for 240 s, starting with 18 F-FDG (250-MBq bolus injection). Four frames at 15-s intervals, followed by 3 frames at 60-s intervals were reconstructed. Endpoints included focal tracer accumulation in the first 4 frames (60 s), subsequent focal washout, and visual and quantitative differences between tumor and liver regions of interest in maximum and mean ED standardized uptake value (ED SUVmax and ED SUVmean, respectively) 240-s time-activity curves. Results: All 34 lesions were identified by early focal 18 F-FDG accumulation and faster time-to-peak ED SUVmax or ED SUVmean than in nontumor tissue. Tumor peak ED SUVmax and ED SUVmean exceeded liver levels in 85% and 53%, respectively, of lesions. Nadir tumor signal showed no consistent pattern relative to nontumor signal. HCC had a significantly shorter time to peak and significantly faster rate to peak for both ED SUVmax and ED SUVmean curves and a significantly higher peak ED SUVmax but not peak ED SUVmean than the liver. Conclusion: This pilot study provided proof of principle that our simplified ED 18 F-FDG PET/CT protocol includes endpoints that effectively detect HCC hypervascularization; this finding suggests that the protocol can be used routinely.

Detectability of hypervascularity in early dynamic PET depends on tracer kinetics: 18F‐FDG versus 68Ga‐DOTATOC in hepatic NET metastasis

“…Recent publications underline FDG‐edPET's potential to depict arterial liver lesion hypervascularisation , again demonstrated here. FDG‐edPET may be useful in patients in whom contrast‐enhanced imaging is contraindicated.…”

Clinical role of early dynamic FDG-PET/CT for the evaluation of renal cell carcinoma

“…However, this protocol intrinsically contains a masking effect of the tracer in the urine and renal parenchyma. Technical developments in FDG-PET/ CT with early dynamic (ED) scans have enabled the estimation of tumour blood flow in hepatocellular carcinoma [10,11], pancreatic cancer [12] and bladder cancer [13]. The ability to estimate tumour blood flow and metabolic activity from a single FDG-PET/CT study may enhance the ability to detect and characterize RCC tumours.…”

Application of Different Imaging Methods in the Early Diagnosis of Primary Hepatic Carcinoma

“…Early dynamic 18 F-FDG PET/CT can diagnose HCC nodules with hypervascularization when other morphologic imaging modalities are unsuitable. In the study of Schierz et al [ 35 ], patients with hypervascularization on CECT underwent liver early dynamic 18 F-FDG PET/CT. SUVmax of tumor peak exceeded liver levels in 85% lesions.…”