Aim:. The aim of this paper is to describe the imaging pattern of focal nod
ular hyperplasia (FNH) by F-18-fluorodeoxyglucose (18F-FDG) positron emissi
on tomography (PET). Methods: Eight consecutive asymptomatic patients with
histologic proof of FNH underwent 18F-FDG PET imaging. The lesions were fou
nd incidentally. The 18F-FDG PET imaging was performed with a dedicated PET
tomograph after intravenous injection of 300-370 MBq 18F-FDG. The 18F-FDG
accumulation in the lesions was (semi)quantified by calculating the standar
dized uptake value (SUV) and SUV has been corrected for the lean body mass
(LBM). Eight patients with liver metastases spread from melanoma (n=2) and
colorectal carcinoma (n=6) served as controls. The size of the FNH lesions
and of the control group ranged from 2.0 to 8.5 cm (mean 4.83 cm+/-2.37) an
d from 1.5 to 6 cm (mean 3.28+/-1.52), respectively. Results: While in mali
gnant liver lesions the accumulation of 18F-FDG was significantly increased
, all FNH lesions showed normal or even decreased accumulation of 18F-FDG.
In FNH lesions, SUV ranged between 1.5 and 2.6 (mean 2.12+/-0.38), whereas
all liver metastases showed an increased SW ranging between 6.20 and 16.00
(mean 10.07+/-3.79). The SUV corrected for LMB (SUVLBM) was similar to the
SW and ranged between 0.9 and 2.2 (mean 1.81+/-0.41) for FNH and between 5.
9 and 16.3 (mean 9.15+/-4.03), respectively. Conclusion. In contrast to liv
er metastases, there is no increased glucose metabolism in FNH in vivo. The
imaging feature of FNH by 18F-FDG-PET imaging is not specific for FNH; how
ever, it may be helpful to differentiate FNH from liver metastases in cance
r patients if radiological methods are not diagnostic.