title: The precision of textural analysis in (18)F-FDG-PET scans of oesophageal cancer.
abstract: OBJECTIVE
  Measuring tumour heterogeneity by textural analysis in (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) provides predictive and prognostic information but technical aspects of image processing can influence parameter measurements. We therefore tested effects of image smoothing, segmentation and quantisation on the precision of heterogeneity measurements.
  
  
  METHODS
  Sixty-four (18)F-FDG PET/CT images of oesophageal cancer were processed using different Gaussian smoothing levels (2.0, 2.5, 3.0, 3.5, 4.0 mm), maximum standardised uptake value (SUVmax) segmentation thresholds (45%, 50%, 55%, 60%) and quantisation (8, 16, 32, 64, 128 bin widths). Heterogeneity parameters included grey-level co-occurrence matrix (GLCM), grey-level run length matrix (GLRL), neighbourhood grey-tone difference matrix (NGTDM), grey-level size zone matrix (GLSZM) and fractal analysis methods. The concordance correlation coefficient (CCC) for the three processing variables was calculated for each heterogeneity parameter.
  
  
  RESULTS
  Most parameters showed poor agreement between different bin widths (CCC median 0.08, range 0.004-0.99). Segmentation and smoothing showed smaller effects on precision (segmentation: CCC median 0.82, range 0.33-0.97; smoothing: CCC median 0.99, range 0.58-0.99).
  
  
  CONCLUSIONS
  Smoothing and segmentation have only a small effect on the precision of heterogeneity measurements in (18)F-FDG PET data. However, quantisation often has larger effects, highlighting a need for further evaluation and standardisation of parameters for multicentre studies.
  
  
  CONCLUSIONS
  • Heterogeneity measurement precision in (18) F-FDG PET is influenced by image processing methods. • Quantisation shows large effects on precision of heterogeneity parameters in (18) F-FDG PET/CT. • Smoothing and segmentation show comparatively smaller effects on precision of heterogeneity parameters.
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK.
authors.forename: Georgia
authors.initials: G
authors.lastname: Doumou
authors.forename: Musib
authors.initials: M
authors.lastname: Siddique
authors.forename: Charalampos
authors.initials: C
authors.lastname: Tsoumpas
authors.forename: Vicky
authors.initials: V
authors.lastname: Goh
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Cook
mesh_terms: D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging*; D004947:Esophagus / Q000000981:diagnostic imaging; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18