gms | German Medical Science

57th Annual Meeting of the German Society of Neurosurgery
Joint Meeting with the Japanese Neurosurgical Society

German Society of Neurosurgery (DGNC)

11 - 14 May, Essen

Differentiation of tumorous and non-tumorous intracerebral ring-enhancing lesions with positron emission tomography (PET) using the amino acid [18F]-fluoroethyl-l-tyrosine (FET)

Unterscheidung neoplastischer von nicht neoplastischen Läsionen mit Ringenhancement durch ein Aminosäure-PET mit [18F]-fluoroethyl-l-tyrosine (FET)

Meeting Abstract

  • corresponding author F. Floeth - Neurochirurgische Klinik, Heinrich-Heine-Universität Düsseldorf
  • K.J. Langen - Brain Imaging Center West, Institute of Medicine, Research Center Jülich
  • D. Pauleit - Institute of Nuclear Chemistry, Research Center Jülich
  • G. Reifenberger - Neuropathologie, Heinrich-Heine-Universität Düsseldorf
  • W. Stummer - Neurochirurgische Klinik, Heinrich-Heine-Universität Düsseldorf
  • H.J. Steiger - Neurochirurgische Klinik, Heinrich-Heine-Universität Düsseldorf
  • M. Sabel - Neurochirurgische Klinik, Heinrich-Heine-Universität Düsseldorf

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 57. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie. Essen, 11.-14.05.2006. Düsseldorf, Köln: German Medical Science; 2006. DocFR.08.04

The electronic version of this article is the complete one and can be found online at:

Published: May 8, 2006

© 2006 Floeth et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: The aim of this study was to explore the differential diagnostic value of positron emission tomography (PET) using the amino acid [18F]-fluoroethyl-l-tyrosine (FET) in patients with newly diagnosed solitary intracerebral lesions showing ring-enhancement on contrast-enhanced magnetic resonance imaging (MRI).

Methods: FET-PET analyses were carried out on 15 consecutive patients with intracerebral ring-enhancing lesions. In addition eleven of the patients were studied with 2-[18F]fluoro-2-deoxy-D-glucose (FDG)-PET. In all patients, the main differential diagnosis after MRI was a malignant lesion, in particular glioblastoma multiforme, versus a benign lesion, in particular a brain abscess. Based on FET-PET, a malignant tumor was suspected for lesions showing increased FET-uptake, with a lesion-to-brain ratio ≥1.6 (FET-PET positive). A non-neoplastic lesion was suspected in case of minimal or absent FET-uptake with a lesion-to-brain ratio <1.6 (FET-PET negative). Histologic diagnosis was obtained by serial biopsies in 14 of the 15 patients. One patient refused the biopsy but follow-up indicated an abscess because his lesion regressed under antibiotic therapy.

Results: Histology and clinical follow-up showed high-grade malignant gliomas in 6 patients and non-neoplastic lesions in 9 patients. FET-PET was positive in all 6 glioma patients as well as in 3 out of 9 patients with non-neoplastic lesions, including 2 patients with brain abscesses and 1 patient with a demyelinating lesion. FDG-PET was positive (lesion-to-gray matter ratio ≥0.7) in 4 out of 4 glioma patients and 3 out of 7 patients with non-neoplastic lesions.

Conclusions: Although FET-PET has been shown to be a very valuable method for the diagnostic evaluation of brain tumors, our data indicate a limited specificity of FET-PET, like FDG-PET, for the distinction between neoplastic and non-neoplastic ring-enhancing intracerebral lesions. Thus, histological investigation of biopsy specimens remains mandatory to solve this important differential diagnosis.