The potential use of 2-[¹⁸F]fluoro-2-deoxy-D-galactose as a PET/CT tracer for detection of hepatocellular carcinoma

Abstract

Purpose: The aim of the study was to evaluate the feasibility of using the hepatocyte-specific positron emission tomography (PET) tracer 2-[(18)F]fluoro-2-deoxy-D-galactose (FDGal) as a tracer for hepatocellular carcinoma (HCC).

Methods: In addition to standard clinical investigations, 39 patients with known HCC or suspected of having HCC underwent a partial-body FDGal PET/CT (from base of skull to mid-thigh). Diagnosis of HCC was based on internationally approved criteria. FDGal PET/CT images were analysed for areas with high (hot spots) or low (cold spots) tracer accumulation when compared to surrounding tissue.

Results: Seven patients did not have HCC and FDGal PET/CT was negative in each of them. Twenty-three patients had HCC and were included before treatment. FDGal PET/CT correctly identified 22 of these patients, which was comparable to contrast-enhanced CT. Interestingly, FDGal PET/CT was conclusive in 12 patients in whom conventional imaging techniques were inconclusive and required additional diagnostic investigations or close follow-up. Nine patients were included after treatment of HCC and in these patients FDGal PET/CT was able to distinguish between viable tumour tissue as hot spots and areas with low metabolic activity as cold spots. FDGal PET/CT detected extrahepatic disease in nine patients which was a novel finding in eight patients.

Conclusion: FDGal PET/CT has great clinical potential as a PET tracer for detection of extra- but also intrahepatic HCC. In the present study, the specificity of FDGal PET/CT was 100%, which is very promising but needs to be confirmed in a larger, prospective study.

Fig 1

PET/CT image of an FDGal positive HCC lesion (arrow) in a cirrhotic liver (ID33; coronal view). The diagnosis was based on plasma AFP (1076 ng/ml) and multi-phase ceCT according to internationally approved guidelines [5, 6]. The aetiology was alcoholic cirrhosis.

Fig. 2

FDGal PET/CT image (a) and ceCT image in arterial phase (b) of a large necrotic HCC (white arrows) with adjacent viable tumour tissue (red arrows) (ID22, transaxial view). The patient did not have cirrhosis and the aetiology was unknown. Plasma AFP was 3047 ng/ml and the multi-phase ceCT typical for HCC [5, 6].

Fig. 3

Example of a large HCC with low metabolic activity seen as an area with low FDGal uptake on the FDGal PET/CT image (a), atypical low contrast-enhancement in the arterial phase of multi-phase ceCT, and typical washout pattern in the late venous phase on ceCT(c) (ID12, transaxial view). A biopsy showed HCC (medium differentiated). The aetiology was alcoholic cirrhosis and plasma AFP was 11 ng/ml.

Fig. 4

FDGal PET/CT image showing a metastasis in the neck of the left femur bone (ID27, coronal view). The liver is large and cirrhotic with no visible tumours in this plane. Radioactivity in the kidneys is physiological due to excretion of FDGal in the urine. The patient had cirrhosis (hepatitis C) and HCC was verified by biopsy. AFP was 13 ng/ml.