title: 4D-PET/CT with [(11)C]-PK11195 and [(11)C]-(D)-deprenyl does not identify the chronic inflammation in asymptomatic abdominal aortic aneurysms.
abstract: OBJECTIVE
  The aim of this study was to investigate the relevance of inflammation in the pathogenesis of abdominal aortic aneurysm (AAA) in vivo with two novel positron emission tomography (PET) tracers: [(11)C]-PK11195 which targets the translocator protein (18 kDa) expressed on macrophages and [(11)C]-d-deprenyl with a yet unknown target receptor expressed in chronic inflammation.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Five patients were examined with [(11)C]-PK11195-positron emission tomography/computed tomography (PET/CT) and 10 with [(11)C]-d-deprenyl-PET/CT. Nine large AAAs (54-66 mm) scheduled for repair and six small AAA (35-44 mm). All 15 patients were male and the AAAs were all asymptomatic. Regional activity was measured as standardised uptake values (SUVs) and retention index was calculated. Biopsies were taken from the aneurysm wall for histological examinations, in the nine patients operated on.
  
  
  RESULTS
  No aortic uptake was recorded on the visual inspection, neither with [(11)C]-PK11195 nor with [(11)C]-d-deprenyl. For [(11)C]-PK11195 the median SUV of the AAA wall was 0.9 (range 0.8-1.0) and for [(11)C]-d-deprenyl, 0.7 (range 0.4-1.2). No increased uptake was seen in the aneurysmal infrarenal aorta compared with the non-aneurysmal suprarenal aorta. Histological examination of the aneurysm wall showed high inflammatory cell infiltration with lymphocytes and macrophages.
  
  
  CONCLUSIONS
  The chronic inflammation observed in the vessel wall was not detectable with [(11)C]-PK11195 and [(11)C]-d-deprenyl. In order to study the relevance of the inflammation in the pathogenesis of AAA in vivo other PET tracers need to be investigated.
authors: Department of Surgical Sciences, Section of Vascular Surgery, Uppsala University, SE-751 85 Uppsala, Sweden. gustaf@tegler.se
authors: G
authors: G
authors: Tegler
authors: J
authors: J
authors: Sörensen
authors: K
authors: K
authors: Ericson
authors: M
authors: M
authors: Björck
authors: A
authors: A
authors: Wanhainen
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D001025:Aortitis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D058070:Asymptomatic Diseases; D001706:Biopsy; D002250:Carbon Radioisotopes; D002908:Chronic Disease; D006801:Humans; D007546:Isoquinolines; D008264:Macrophages / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012642:Selegiline; D014057:Tomography, X-Ray Computed
chemical_list: D002250:Carbon Radioisotopes; D007546:Isoquinolines; D019275:Radiopharmaceuticals; D012642:Selegiline; C037850:PK 11195