gms | German Medical Science

60th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Benelux countries and Bulgaria

German Society of Neurosurgery (DGNC)

24 - 27 May 2009, Münster

Hot-Spot areas in FET-PET delineate malignant tumour parts within suspected WHO grade II glioma

Meeting Abstract

  • M. Kunz - Klinik für Neurochirurgie, Klinikum Großhadern, Ludwig-Maximilians-Universität, München
  • R. Egensperger - Institut für Neuropathologie, Klinikum Großhadern, Ludwig-Maximilians-Universität, München
  • G. Pöpperl - Klinik für Nuklearmedizin, Klinikum Großhadern, Ludwig-Maximilians-Universität, München
  • H. Kretzschmar - Institut für Neuropathologie, Klinikum Großhadern, Ludwig-Maximilians-Universität, München
  • J.-C. Tonn - Klinik für Neurochirurgie, Klinikum Großhadern, Ludwig-Maximilians-Universität, München
  • F.-W. Kreth - Klinik für Neurochirurgie, Klinikum Großhadern, Ludwig-Maximilians-Universität, München

Deutsche Gesellschaft für Neurochirurgie. 60. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit den Benelux-Ländern und Bulgarien. Münster, 24.-27.05.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. DocMO.06-05

doi: 10.3205/09dgnc031, urn:nbn:de:0183-09dgnc0316

Published: May 20, 2009

© 2009 Kunz 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: Metabolic imaging such as O-(2-18F-fluoroethyl)-L thyrosine (FET) positron emission tomography (PET) often revealed heterogeneous findings in suspected WHO grade II glioma showing one or more HOT-SPOT area(s). To which extent these HOT-SPOTS correlate with malignant tumour parts, has never been elucidated; conversely, it still has to be shown, whether non-HOT-SPOT areas indicate more benign tumour parts. For prospective clarification, a correlative topographical analysis of FET-PET imaging and neuro-pathological findings was conducted.

Methods: Adult patients with an MRI-based suspicion of a supratentorial WHO Grade II glioma were included after prior informed consent. For stepwise non-invasive tumour grading of each tumour, maps of FET uptake kinetics were generated, as described elsewhere (Eur J Nucl Med Mol Imaging, 2007). Tumour parts with suspected malignant behaviour (HOT-SPOT areas) were outlined three-dimensionally. After co-registration of MRI and PET data, stereotactic serial biopsy was performed along a trajectory, which includes the HOT-SPOT volume (if present). Tissue samples were taken in 1 mm steps from within and outside the HOT-SPOT areas. Each of these was scored with regard to its position within the stereotactically defined tumour space, and evaluated independently by two neuro-pathologists unaware of the PET-findings. Grading was done according to WHO criteria and in addition, the Ki-67 labelling index was calculated.

Results: Thirty-seven patients were included. Nineteen samples per tumour (median) were evaluated. 28 tumours showed a benign kinetic (no HOT-SPOT) and stepwise histological evaluation indicated Grade II characteristics in 26 of these tumours. Two tumours exhibited Grade III characteristics. In 9 tumours HOT-SPOT areas were detected: Stepwise histological evaluation revealed Grade II characteristics outside and Grade III characteristics within the HOT SPOT in 6 tumours; in 3 tumours the entire tumour volume was overshadowed by the HOT-SPOT volume and Grade III characteristics were seen throughout these tumours. HOT-SPOT areas were associated with a significant higher Ki-67 labelling (15% vs. 4%, p<0.01). The labelling index outside the HOT-SPOT area was similar to that of tumours lacking HOT-SPOT areas at all (p=0.3).

Conclusions: Suspected low-grade gliomas are heterogeneously composed and HOT-SPOT areas delineate malignant tumour parts. These findings have implications for biopsy and treatment planning.