Application of 11C-acetate PET/CT imaging in the detection of recurrence and metastasis of hepatocellular carcinoma with intermediate and high differentiation

Abstract

Objectives To investigate the value of 11C-acetate PET/CT imaging in the detection of the recurrence and metastasis of hepatocellular carcinoma (HCC) with high or medium differentiation. Methods A total of 10 patients who underwent surgical or interventional therapy, had moderately or highly differentiated HCC, underwent 11C-acetate and 18F-FDG PET/CT trunk imaging from January 2015 to December 2016 were retrospectively analyzed. Progressive increases in alpha fetoprotein were observed in the patients after the treatment. 11C-acetate and 18F-FDG PET/CT scan were performed on the patients in one week, and the diagnostic values of the two tracers were compared. In the PET images, the lesion was positive when the metabolic level of the lesion was higher than that of a normal liver tissue and negative when the metabolic level of the lesion was lower than or same as that of a normal liver tissue. The maximum standardized uptake value(SUVmax) and the ratio of target to background(T/B) were calculated by outlining the areas of interest. All patients were diagnosed with metastasis or recurrence by pathology or imaging examination. Results Six patients had moderately differentiated HCC and four patients had highly differentiated HCC. 11C-acetate imaging revealed 18 positive lesions, and the sensitivity was 100%(18/18). Five positive lesions were found in 18F-FDG images, and the sensitivity was 27.8%(5/18). Two tracers revealed five positive lesions (in four patients with moderately differentiated HCC). The sensitivity of 11C-acetate imaging to detect lesions was the same as that of double tracers combined imaging. The SUVmax range of 11C-acetate imaging was 1.3-14.2, and the range of T/B was 1.1-14.3. The SUVmax range of 18F-FDG imaging was 0.5-3.4, and the range of T/B was 0.6-1.1. Eight patients (13 lesions) were pathologically confirmed to have tumor recurrence or metastasis, and two patients (5 lesions) proved to be metastatic after 3 months of follow-up. Conclusions 11C-acetate imaging can significantly improve the sensitivity of the diagnosis of recurrence and metastasis of moderately and highly differentiated HCC. 11C- acetate imaging is expected to replace 18F-FDG imaging in monitoring recurrence and metastasis in moderately and highly differentiated HCC. Key words: Carcinoma, hepatocellular; Fluorodeoxyglucose F18; Acetates; Positron emission tomography computed tomography