title: Impact of Image Reconstruction Settings on Texture Features in 18F-FDG PET.
abstract: Evaluation of tumor heterogeneity based on texture parameters has recently attracted much interest in the PET imaging community. However, the impact of reconstruction settings on texture parameters is unclear, especially relating to time-of-flight and point-spread function modeling. Their effects on 55 texture features (TFs) and 6 features based on first-order statistics (FOS) were investigated. Standardized uptake value (SUV) measures were also evaluated as peak SUV (SUVpeak), maximum SUV, and mean SUV (SUVmean).
  
  
  METHODS
  This study retrospectively recruited 20 patients with lesions in the lung who underwent whole-body (18)F-FDG PET/CT. The coefficient of variation (COV) of each feature across different reconstructions was calculated.
  
  
  RESULTS
  SUVpeak, SUVmean, 18 TFs, and 1 FOS were the most robust (COV ≤ 5%) whereas skewness, cluster shade, and zone percentage were the least robust (COV > 20%) with respect to reconstruction algorithms using default settings. Heterogeneity parameters had different sensitivities to iteration number. Twenty-four parameters including SUVpeak and SUVmean exhibited variation with a COV less than 5%; 28 parameters, including maximum SUV, showed variation with a COV in the range of 5%-10%. In addition, skewness, cluster shade, and zone percentage were the most sensitive to iteration number. In terms of sensitivity to full width at half maximum (FWHM), 15 TFs and 1 FOS had the best performance with a COV less than 5%, whereas SUVpeak and SUVmean had a COV between 5% and 10%. Grid size had the largest impact on image features, which was demonstrated by only 11 features, including SUVpeak and SUVmean, having a COV less than 10%.
  
  
  CONCLUSIONS
  Different image features have different sensitivities to reconstruction settings. Iteration number and FWHM of the gaussian filter have a similar impact on the image features. Grid size has a larger impact on the features than iteration number and FWHM. The features that exhibited large variations such as skewness in FOS, cluster shade, and zone percentage should be used with caution. The entropy in FOS, difference entropy, inverse difference normalized, inverse difference moment normalized, low gray-level run emphasis, high gray-level run emphasis, and low gray-level zone emphasis are the most robust features.
authors.affiliation: A*STAR-NUS, Clinical Imaging Research Center, Singapore yan_jianhua@circ.a-star.edu.sg.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Yan
authors.affiliation: A*STAR-NUS, Clinical Imaging Research Center, Singapore.
authors.forename: Jason Lim
authors.initials: JL
authors.lastname: Chu-Shern
authors.affiliation: Department of Diagnostic Radiology, National University Hospital, Singapore; and.
authors.forename: Hoi Yin
authors.initials: HY
authors.lastname: Loi
authors.affiliation: Department of Diagnostic Radiology, National University Hospital, Singapore; and.
authors.forename: Lih Kin
authors.initials: LK
authors.lastname: Khor
authors.affiliation: Department of Diagnostic Radiology, National University Hospital, Singapore; and.
authors.forename: Arvind K
authors.initials: AK
authors.lastname: Sinha
authors.affiliation: Department of Diagnostic Radiology, National University Hospital, Singapore; and.
authors.forename: Swee Tian
authors.initials: ST
authors.lastname: Quek
authors.affiliation: A*STAR-NUS, Clinical Imaging Research Center, Singapore Department of Radiation Oncology, National University Cancer Institute, Singapore.
authors.forename: Ivan W K
authors.initials: IW
authors.lastname: Tham
authors.affiliation: A*STAR-NUS, Clinical Imaging Research Center, Singapore Department of Diagnostic Radiology, National University Hospital, Singapore; and.
authors.forename: David
authors.initials: D
authors.lastname: Townsend
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003627:Data Interpretation, Statistical; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D051598:Whole Body Imaging
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG PET; point-spread function; time-of-flight; tumor texture