title: Textural features of18F-fluorodeoxyglucose positron emission tomography scanning in diagnosing aortic prosthetic graft infection.
abstract: BACKGROUND
  The clinical problem in suspected aortoiliac graft infection (AGI) is to obtain proof of infection. Although18F-fluorodeoxyglucose (18F-FDG) positron emission tomography scanning (PET) has been suggested to play a pivotal role, an evidence-based interpretation is lacking. The objective of this retrospective study was to examine the feasibility and utility of18F-FDG uptake heterogeneity characterized by textural features to diagnose AGI.
  
  
  METHODS
  Thirty patients with a history of aortic graft reconstruction who underwent18F-FDG PET/CT scanning were included. Sixteen patients were suspected to have an AGI (group I). AGI was considered proven only in the case of a positive bacterial culture. Positive cultures were found in 10 of the 16 patients (group Ia), and in the other six patients, cultures remained negative (group Ib). A control group was formed of 14 patients undergoing18F-FDG PET for other reasons (group II). PET images were assessed using conventional maximal standardized uptake value (SUVmax), tissue-to-background ratio (TBR), and visual grading scale (VGS). Additionally, 64 different18F-FDG PET based textural features were applied to characterize18F-FDG uptake heterogeneity. To select candidate predictors, univariable logistic regression analysis was performed (α = 0.16). The accuracy was satisfactory in case of an AUC > 0.8.
  
  
  RESULTS
  The feature selection process yielded the textural features named variance (AUC = 0.88), high grey level zone emphasis (AUC = 0.87), small zone low grey level emphasis (AUC = 0.80), and small zone high grey level emphasis (AUC = 0.81) most optimal for distinguishing between groups I and II. SUVmax, TBR, and VGS were also able to distinguish between these groups with AUCs of 0.87, 0.78, and 0.90, respectively. The textural feature named short run high grey level emphasis was able to distinguish group Ia from Ib (AUC = 0.83), while for the same task the TBR and VGS were not found to be predictive. SUVmax was found predictive in distinguishing these groups, but showed an unsatisfactory accuracy (AUC = 0.75).
  
  
  CONCLUSIONS
  Textural analysis to characterize18F-FDG uptake heterogeneity is feasible and shows promising results in diagnosing AGI, but requires additional external validation and refinement before it can be implemented in the clinical decision-making process.
authors.affiliation: Department of Surgery, Division of Vascular Surgery, University of Groningen, University Medical Center Groningen, P.O. Box 30 001, 9700 RB, Groningen, The Netherlands. r.b.saleem@gmail.com.
authors.forename: Ben R
authors.identifier: http://orcid.org/0000-0002-7679-2791
authors.initials: BR
authors.lastname: Saleem
authors.affiliation: Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.|Department of Biomedical Photonic Imaging (BMPI), University of Twente, Enschede, The Netherlands.
authors.forename: Roelof J
authors.initials: RJ
authors.lastname: Beukinga
authors.affiliation: Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Ronald
authors.initials: R
authors.lastname: Boellaard
authors.affiliation: Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Andor W J M
authors.initials: AW
authors.lastname: Glaudemans
authors.affiliation: Department of Surgery, Rijnstate Hospital, Arnhem, The Netherlands.
authors.forename: Michel M P J
authors.initials: MM
authors.lastname: Reijnen
authors.affiliation: Department of Surgery, Division of Vascular Surgery, University of Groningen, University Medical Center Groningen, P.O. Box 30 001, 9700 RB, Groningen, The Netherlands.
authors.forename: Clark J
authors.initials: CJ
authors.lastname: Zeebregts
authors.affiliation: Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.|Department of Biomedical Photonic Imaging (BMPI), University of Twente, Enschede, The Netherlands.
authors.forename: Riemer H J A
authors.initials: RH
authors.lastname: Slart
mesh_terms: D000328:Adult; D000368:Aged; D001011:Aorta / Q000000981:diagnostic imaging* / Q000382:microbiology / Q000601:surgery; D001692:Biological Transport; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging* / Q000378:metabolism; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG PET; Aortic prosthetic graft infection; Textural features