Liver 2000: 20: 487–490 Copyright C Munksgaard 2000 Printed in Denmark . All rights reserved Liver ISSN 0106-9543 18 F-Fluorodeoxyglucose (FDG)-PET features of focal nodular hyperplasia (FNH) of the liver Kurtaran A, Becherer A, Pfeffel F, Mu ¨ller C, Traub T, Schmaljohann J, Amir Kurtaran 1 , Kaserer K, Raderer M, Schima W, Dudczak R, Kletter K, Virgolini. Alexander Becherer 1 , Franz Pfeffel 2 , 18 F-Fluorodeoxyglucose (FDG)-PET features of focal nodular hyper- Christian Müller 2 , Tatjana Traub 1 , plasia (FNH) of the liver. Jörn Schmaljohann 1 , Liver 2000: 20: 487–490. C Munksgaard, 2000 Klaus Kaserer 3 , Markus Raderer 2 , Wolfgang Schima 4 , Abstract: Aim: The aim of this paper is to describe the imaging pattern Robert Dudczak 1 , Kurt Kletter 1 and of focal nodular hyperplasia (FNH) by 18 F-fluorodeoxyglucose (18F-FDG) Irene Virgolini 1 positron emission tomography (PET). Methods: Eight consecutive asymp- tomatic patients with histologic proof of FNH underwent 18F-FDG Departments of 1 Nuclear Medicine, 2 Internal Medicine, 3 Pathology, and 4 Radiology, University PET imaging. The lesions were found incidentally. The 18F-FDG PET of Vienna, Vienna, Austria 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 standardized uptake value (SUV) and SUV has been corrected for the lean body mass (LBM). Eight patients with liver metastases spread from melanoma (nΩ2) and colorec- tal carcinoma (nΩ6) 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) and from 1.5 to 6 cm (mean 3.28∫1.52), respectively . Results: While in malig- nant liver lesions the accumulation of 18F-FDG was significantly in- creased, 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 SUV rang- Key words: hepatic focal nodular hyperplasia ing between 6.20 and 16.00 (mean 10.07∫3.79). The SUV corrected for (FNH) – 18 F-fluorodeoxyglucose (18F-FDG) – LMB (SUV LBM ) was similar to the SUV and ranged between 0.9 and 2.2 positron emission tomography (PET) (mean 1.81∫0.41) for FNH and between 5.9 and 16.3 (mean 9.15∫4.03), A. Kurtaran, M.D., Department of Nuclear respectively. Conclusion: In contrast to liver metastases, there is no in- Medicine, University of Vienna, Währinger Gürtel creased glucose metabolism in FNH in vivo. The imaging feature of 18–20, A-1090 Vienna, Austria. Tel. and Fax: π43 1 40400 7835. FNH by 18F-FDG-PET imaging is not specific for FNH; however, it may e-mail: amir.kurtaran/akh-wien.ac.at be helpful to differentiate FNH from liver metastases in cancer patients if radiological methods are not diagnostic. Received 19 January, accepted 28 June 2000 Focal nodular hyperplasia (FNH) is a benign he- patic tumor usually discovered incidentally. The lesions are usually asymptomatic and occur mostly in females. In contrast to malignant liver lesions, FNH should be managed conservatively. A large number of imaging modalities have been used to diagnose FNH with variable success. Ultrasono- graphy (US) can only be considered as a screening technique, since the appearance of FNH by US is non-specific. FNH may appear hyperdense or hypodense on computed tomography (CT) and a definite diagnosis of FNH may be challenging, especially if the lesions are small-sized (1, 2). Con- trast-enhanced MRI is the best imaging procedure 487 in the diagnosis of FNH if typical features of FNH are present (1). Nuclear medicine procedures such as 99m Tc-sulfur colloid scintigraphy ( 99m Tc-SC) and trimethyl bromo-imino-diacetic acid (TBIDA) and hepatocyte-specific receptor ligand 99m Tc-gal- actosyl-neoglycoalbumin are other means of diag- nosing FNH which have met with variable success (3–6). PET is a new imaging method that has been suc- cessfully applied to image malignant tumors. While a large number of studies has been pub- lished in the last years about the usefulness of 18F- FDG PET in a variety of malignant diseases, the glucose metabolism of FNH in vivo has not been