title: Modest utility of quantitative measures in (18)F-fluorodeoxyglucose positron emission tomography scanning for the diagnosis of aortic prosthetic graft infection.
abstract: BACKGROUND
  The clinical dilemma in suspected aortic graft infection (AGI) is how to noninvasively obtain a reliable proof of infection. In addition to confirming the presence of infection, obtaining information regarding the extent of infection to select a proper strategy for reoperation is also necessary. Therefore, developing a more reliable noninvasive physiologic approach to detect infected prostheses is required. (18)F-fluorodeoxyglucose positron emission tomography scanning ((18)F-FDG PET) has been suggested to have a pivotal role in the detection of AGI. In this study, we assessed the contribution of two (semi) quantitative parameters-maximal standardized uptake value (SUVmax) and tissue-to-background ratio (TBR)-and of two visual parameters-fluorodeoxyglucose (FDG) distribution patterns and visual grading scale-in the final confirmation of the diagnosis of AGI.
  
  
  METHODS
  Patients with a central aortic prosthetic graft and symptoms clinically suggestive of AGI were gathered from a prospectively maintained database. Included were those who underwent (18)F-FDG PET scanning combined with computed tomography angiography and in whom periprosthetic samples were taken at some stage in the diagnostic process. AGI was considered proven in case of a positive culture and compared with a group with negative cultures. Positive predictive values (PPVs) and negative predictive values (NPVs) were calculated. Receiver operating characteristics curves were used to assess the ability of SUVmax and TBR to identify the presence and absence of AGI (ie, accuracy).
  
  
  RESULTS
  In 37 of 77 patients with suspected AGI, (18)FDG-PET and perigraft material for culturing was obtained. The tissue culture was positive in 21 of these 37 patients (56.7%). Mean ± standard deviation SUVmax for proven infection was 8.1 ± 3.7 (range, 3.6-18.5) and TBR was 5.9 ± 2.7 (range, 1.7-13.0). The area under the curve for SUVmax was 0.78 (95% confidence interval, 0.63-0.93). A cutoff value of 8 yielded a PPV of 80% and a NPV of 54%. The area under the curve for TBR was 0.70 (95% confidence interval, 0.52-0.87). A cutoff value of 6 yielded a PPV of 73% and NPV of 52%. The PPVs for the visual grading scale and (18)F-FDG distribution patterns were 75% and 61%, respectively; the NPVs were 77% and 67%, respectively.
  
  
  CONCLUSIONS
  Our study, performed in a small sample of patients suspected of AGI, showed that the diagnostic abilities of quantitative and visual (18)F-FDG PET parameters are modest.
authors.affiliation: Division of Vascular Surgery, Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Ben R
authors.initials: BR
authors.lastname: Saleem
authors.affiliation: Division of Vascular Surgery, Department of Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Paul
authors.initials: P
authors.lastname: Berger
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Ilonca
authors.initials: I
authors.lastname: Vaartjes
authors.affiliation: Department of Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Bart
authors.initials: B
authors.lastname: de Keizer
authors.affiliation: Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Evert-Jan P A
authors.initials: EJ
authors.lastname: Vonken
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Riemer H J A
authors.initials: RH
authors.lastname: Slart
authors.affiliation: Division of Vascular Surgery, Department of Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Gert Jan
authors.initials: GJ
authors.lastname: de Borst
authors.affiliation: Division of Vascular Surgery, Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. Electronic address: czeebregts@hotmail.com.
authors.forename: Clark J
authors.initials: CJ
authors.lastname: Zeebregts
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000000981:diagnostic imaging* / Q000382:microbiology / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001807:Blood Vessel Prosthesis / Q000009:adverse effects*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation; D016208:Databases, Factual; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging* / Q000382:microbiology; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18