Value of delayed 18F-FDG-PET imaging in the detection of hepatocellular carcinoma

Abstract

In the evaluation of HCC, delayed 2 and 3 h imaging can detect more lesions than standard 1 h imaging. Imaging at 3 h has a better T/N ratio than imaging at 2 h, but does not increase the diagnostic sensitivity.

The Role of Delayed 18F-FDG PET Imaging in the Follow-up of Patients with Alveolar Echinococcosis

“…As observed in liver cancer, better AE lesion detection on delayed 18 F-FDG PET images was due to both reduction of liver background activity and perilesionally increased 18 F-FDG uptake (14)(15)(16)(17)(18). However, in AE, the nature of cells involved in 18 F-FDG uptake is still unknown.…”

“…Koyama et al showed that delayed 18 F-FDG PET image acquisition (2 h after 18 F-FDG injection), also called dual-time-point imaging, improved detection of malignant hepatic lesions (13). Lin et al demonstrated that tumor-to-background ratio in the liver was even higher at a 3-h acquisition than at a 2-h acquisition (14), and further studies confirmed that an improvement of tumor-to-background ratio with better visualization of liver tumors could be obtained by delayed 18 F-FDG PET (15)(16)(17)(18).…”

Imaging of Proliferation in Hepatocellular Carcinoma with the In Vivo Marker 18F-Fluorothymidine

“…Consequently, the trapping of the radiopharmaceutical is reduced, resulting in a lower sensitivity. The sensitivity of 18 F-FDG PET can be increased to 62.5% by delaying the acquisition of PET data for 2-3 h (25). Therefore, the current role of 18 F-FDG PET in HCC applies only to the detection of extrahepatic tumor deposits in patients with 18 F-FDG-avid primary lesions.…”

Underestimated Role of 18F-FDG PET for HCC Evaluation and Promise of 18F-FDG PET/MR Imaging in This Setting

“…The dynamics of 18 F-FDG accumulation in HCCs, benign liver lesions, and background tissue go beyond 60 min after 18 F-FDG administration (the conventional time point at which 18 F-FDG PET is routinely performed, as was also done in the study by Cheung et al (1)) (6)(7)(8). Additional PET imaging at a later time point (i.e., dual-time-point or delayed imaging) may be advantageous because 18 F-FDG accumulation in benign liver lesions and background tissue may decrease (7,8) whereas 18 F-FDG accumulation in HCCs may further increase (6). This, in turn, may improve the detection of both HCCs and metastases.…”

“…The real challenge for the diagnosis of HCC is mainly the low sensitivity for the detection of tumors smaller than 2 cm. The guideline of the American Association for the Study of Liver Diseases suggests that a biopsy is needed if fewer than 2 imaging modalities show typical features of HCC (6). The imaging modalities suggested for small-HCC detection are contrast-enhanced ultrasound and contrast-enhanced MR imaging (7).…”