title: Evaluation of intratumoural heterogeneity on ¹⁸F-FDG PET/CT for characterization of peripheral nerve sheath tumours in neurofibromatosis type 1.
abstract: OBJECTIVE
  The aim of the study was to evaluate the potential usefulness of intratumoural tracer uptake heterogeneity on (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT as compared to a cut-off maximum standardized uptake value (SUVmax) for characterization of peripheral nerve sheath tumours (PNSTs) in neurofibromatosis type 1 (NF1).
  
  
  METHODS
  Fifty patients suffering from NF1 were examined by (18)F-FDG PET/CT. Intralesional tracer uptake was analysed qualitatively and semi-quantitatively by measuring the mean and maximum SUV. Uptake heterogeneity was graded qualitatively using a three-point scale and semi-quantitatively by calculating an SUV-based heterogeneity index (HISUV). Cohen's κ was used to determine inter- and intra-rater agreement. Histopathological evaluation and clinical as well as radiological follow-up examinations served as the reference standards.
  
  
  RESULTS
  A highly significant correlation between the degree of intratumoural uptake heterogeneity on (18)F-FDG PET and malignant transformation of PNSTs was observed (p < 0.0001). Semi-quantitative HISUV was significantly higher in malignant PNSTs (MPNSTs) than in benign tumours (p = 0.0002). Both intralesional heterogeneity and SUVmax could be used to identify malignant tumours with a sensitivity of 100 %. Cohen's κ was 0.86 for inter-rater agreement and 0.88 for intra-rater agreement on heterogeneity.
  
  
  CONCLUSIONS
  MPNSTs in patients with NF1 demonstrate considerable intratumoural uptake heterogeneity on (18)F-FDG PET/CT. Assessment of tumour heterogeneity is highly reproducible. Both tumour heterogeneity and a cut-off SUVmax may be used to sensitively identify malignant PNSTs, but the specificity is higher for the latter. A combination of both methods leads to a non-significant improvement in diagnostic performance.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany. j.salamon@uke.de
authors.forename: Johannes
authors.initials: J
authors.lastname: Salamon
authors.forename: Thorsten
authors.initials: T
authors.lastname: Derlin
authors.forename: Peter
authors.initials: P
authors.lastname: Bannas
authors.forename: Jasmin D
authors.initials: JD
authors.lastname: Busch
authors.forename: Jochen
authors.initials: J
authors.lastname: Herrmann
authors.forename: Maximilian
authors.initials: M
authors.lastname: Bockhorn
authors.forename: Christian
authors.initials: C
authors.lastname: Hagel
authors.forename: Reinhard E
authors.initials: RE
authors.lastname: Friedrich
authors.forename: Gerhard
authors.initials: G
authors.lastname: Adam
authors.forename: Victor F
authors.initials: VF
authors.lastname: Mautner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001692:Biological Transport; D002648:Child; D002675:Child, Preschool; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D018317:Nerve Sheath Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D009456:Neurofibromatosis 1 / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D049268:Positron-Emission Tomography; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18