title: What is the relationship between ¹⁸F-FDG aortic aneurysm uptake on PET/CT and future growth rate?
abstract: OBJECTIVE
  In this study we investigate the relationship between (18)F-fluorodeoxyglucose (FDG) metabolism and future aneurysm expansion measured by serial duplex ultrasound. Current screening programmes are increasing the identification of patients with abdominal aortic aneurysm (AAA). The management of these patients remains challenging and methods of risk stratification are sought.
  
  
  METHODS
  Thirty-four consecutive patients [31 men, 3 women, median age 75 years, interquartile range (IQR) 71-78] with aortic aneurysms under routine surveillance with serial ultrasound were prospectively recruited for (18)F-FDG positron emission tomography (PET)/CT. A whole vessel type analysis was performed measuring the highest aortic wall (18)F-FDG uptake (standardized uptake value or SUV(max)), and target to background ratio (TBR) for each axial image and median SUV(max) and TBR value were calculated. Institutional Review Board permission and informed patient consent were obtained.
  
  
  RESULTS
  Nine patients failed to undergo 12-month follow-up study (deceased n = 2, withdrew n = 1, failed to attend ultrasound scan n = 5, emergency aneurysm repair n = 1) leaving 25 patients for analysis. The median whole vessel SUV(max) was 1.70 (IQR 1.45-2.08). The median whole vessel TBR was 1.15 (IQR 1.00-1.40). The median aneurysm expansion at 12 months was 2.0 mm (IQR 0.5-5.0). The correlation (r) between (18)F-FDG SUV(max) and ultrasound expansion at 1 year was -0.501 (p = 0.011).
  
  
  CONCLUSIONS
  The preliminary findings from this observational longitudinal pilot study suggest that there is an inverse trend between (18)F-FDG uptake on PET and future AAA expansion. Aortic aneurysms with lower metabolic activity may therefore be more likely to expand.
authors.affiliation: Department of Vascular Surgery, Brighton and Sussex University Hospital, Eastern Road, Brighton BN2 5BE, UK.
authors.forename: Carl W
authors.initials: CW
authors.lastname: Kotze
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Groves
authors.forename: Leon J
authors.initials: LJ
authors.lastname: Menezes
authors.forename: Richard
authors.initials: R
authors.lastname: Harvey
authors.forename: Raymondo
authors.initials: R
authors.lastname: Endozo
authors.forename: Irfan A
authors.initials: IA
authors.lastname: Kayani
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Ell
authors.forename: Syed W
authors.initials: SW
authors.lastname: Yusuf
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D001692:Biological Transport; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006801:Humans; D008297:Male; D015588:Observer Variation; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D019788:Fluorodeoxyglucose F18