title: Inflammation in the walls of asymptomatic abdominal aortic aneurysms is not associated with increased metabolic activity detectable by 18-fluorodeoxglucose positron-emission tomography.
abstract: OBJECTIVE
  We hypothesized that the general inflammation observed in the wall of large, asymptomatic abdominal aortic aneurysms (AAAs) could be detected in vivo by 18-fluorodeoxglucose (FDG) positron-emission tomography (PET) and, if so, that this method could be used to study if active inflammation is an early pathogenetic finding in small AAAs detected by screening.
  
  
  METHODS
  In this prospective clinical study, 12 men were examined with FDG-PET computed tomography. Seven had large asymptomatic AAAs (range, 52-66 mm) that required surgery, and five had small AAAs (range, 34-40 mm) under surveillance. In the surgery group, biopsy specimens were taken from the aneurysm wall for histologic examinations.
  
  
  RESULTS
  Compared with normal segments of the aorta, liver, and blood and compared with healthy controls matched for age and sex, no increased FDG uptake, measured as standardized uptake value, was detected in any of the large or small AAAs. The SUV(mean) difference between infrarenal aorta and blood was -0.3 for cases and -0.1 for controls (P = .06). The corresponding differences between the infrarenal aorta and liver was -0.8 and -0.8 (P = .91) and between infrarenal aorta and suprarenal aorta was -0.2 and -0.1 for cases and controls, respectively (P = .20). The histologic examination of the aneurysm walls showed high inflammatory cell infiltration with T lymphocytes, B lymphocytes, and macrophages.
  
  
  CONCLUSIONS
  The chronic inflammation observed in the wall of asymptomatic AAAs was not sufficiently metabolically active to result in an increased glucose metabolism detectable by FDG-PET by means of this standard protocol. To study the importance of inflammation in the pathogenesis of AAAs in vivo, PET tracers other than FDG need to be developed.
authors.affiliation: Department of Surgical Sciences, Section of Vascular Surgery, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Gustaf
authors.initials: G
authors.lastname: Tegler
authors.forename: Katharina
authors.initials: K
authors.lastname: Ericson
authors.forename: Jens
authors.initials: J
authors.lastname: Sörensen
authors.forename: Martin
authors.initials: M
authors.lastname: Björck
authors.forename: Anders
authors.initials: A
authors.lastname: Wanhainen
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D001025:Aortitis / Q000000981:diagnostic imaging* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D058070:Asymptomatic Diseases; D001706:Biopsy; D016022:Case-Control Studies; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D008214:Lymphocytes / Q000000981:diagnostic imaging / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000000981:diagnostic imaging / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008297:Male; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000378:metabolism; D013548:Sweden
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18