title: Robustness of intratumour ¹⁸F-FDG PET uptake heterogeneity quantification for therapy response prediction in oesophageal carcinoma.
abstract: OBJECTIVE
  Intratumour uptake heterogeneity in PET quantified in terms of textural features for response to therapy has been investigated in several studies, including assessment of their robustness for reconstruction and physiological reproducibility. However, there has been no thorough assessment of the potential impact of preprocessing steps on the resulting quantification and its predictive value. The goal of this work was to assess the robustness of PET heterogeneity in textural features for delineation of functional volumes and partial volume correction (PVC).
  
  
  METHODS
  This retrospective analysis included 50 patients with oesophageal cancer. PVC of each PET image was performed. Tumour volumes were determined using fixed and adaptive thresholding, and the fuzzy locally adaptive Bayesian algorithm, and heterogeneity was quantified using local and regional textural features. Differences in the absolute values of the image-derived parameters considered were assessed using Bland-Altman analysis. The impact on their predictive value for the identification of patient nonresponders was assessed by comparing areas under the receiver operating characteristic curves.
  
  
  RESULTS
  Heterogeneity parameters were more dependent on delineation than on PVC. The parameters most sensitive to delineation and PVC were regional ones (intensity variability and size zone variability), whereas local parameters such as entropy and homogeneity were the most robust. Despite the large differences in absolute values obtained from different delineation methods or after PVC, these differences did not necessarily translate into a significant impact on their predictive value.
  
  
  CONCLUSIONS
  Parameters such as entropy, homogeneity, dissimilarity (for local heterogeneity characterization) and zone percentage (for regional characterization) should be preferred. This selection is based on a demonstrated high differentiation power in terms of predicting response, as well as a significant robustness with respect to the delineation method used and the partial volume effects.
authors.affiliation: INSERM, UMR 1101, LaTIM, CHRU Morvan, 2 avenue Foch, 29609, Brest, France, hatt@univ-brest.fr.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Hatt
authors.forename: Florent
authors.initials: F
authors.lastname: Tixier
authors.forename: Catherine
authors.initials: C
authors.lastname: Cheze Le Rest
authors.forename: Olivier
authors.initials: O
authors.lastname: Pradier
authors.forename: Dimitris
authors.initials: D
authors.lastname: Visvikis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D003627:Data Interpretation, Statistical; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18