title: Assessment of aortitis by semiquantitative analysis of 180-min 18F-FDG PET/CT acquisition images.
abstract: OBJECTIVE
  The aim of this study was to evaluate the contribution of semiquantitative analysis of 180-min (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT images for the assessment of aortitis in cases of suspected large vessel vasculitis (LVV) and to establish a threshold index for application in the clinical setting.
  
  
  METHODS
  This prospective study included 43 patients (mean age 67.5 ± 12.9 years) with suspicion of LVV (25 with a final diagnosis of aortitis). (18)F-FDG PET/CT scan was acquired 180 min after injection of 7 MBq/kg of (18)F-FDG. A semiquantitative analysis was performed calculating the aortic wall maximum standardized uptake value (SUVmax) (T), the lumen SUVmax (B) and the target to background ratio (TBR). These results were also compared with those obtained in a control population.
  
  
  RESULTS
  The mean aortic wall SUVmax was 2.00 ± 0.62 for patients with aortitis and 1.45 ± 0.31 for patients without aortitis (p < 0.0001). The TBR was 1.66 ± 0.26 for patients with aortitis and 1.24 ± 0.08 for patients without aortitis (p < 0.0001). The differences were also statistically significant when the patients with aortitis and controls were compared. Receiver-operating characteristic (ROC) analysis revealed that the area under the curve was greater for the TBR than for the aortic wall SUVmax (0.997 vs 0.871). The highest sensitivity and specificity was obtained for a TBR of 1.34 (sensitivity 100%, specificity 94.4%).
  
  
  CONCLUSIONS
  Semiquantitative analysis of PET/CT images acquired 180 min after (18)F-FDG injection and the TBR index of 1.34 show very high accuracy and, therefore, are strongly recommended for the diagnosis of aortitis in the clinical setting.
authors: Department of Nuclear Medicine, Marqués de Valdecilla University Hospital, University of Cantabria, Santander, Spain, mimartinez@humv.es.
authors: Isabel
authors: I
authors: Martínez-Rodríguez
authors: N
authors: N
authors: Martínez-Amador
authors: I
authors: I
authors: Banzo
authors: R
authors: R
authors: Quirce
authors: J
authors: J
authors: Jiménez-Bonilla
authors: M
authors: M
authors: De Arcocha-Torres
authors: S
authors: S
authors: Ibáñez-Bravo
authors: C
authors: C
authors: Lavado-Pérez
authors: Z
authors: Z
authors: Bravo-Ferrer
authors: R
authors: R
authors: Blanco
authors: M A
authors: MA
authors: González-Gay
authors: J M
authors: JM
authors: Carril
mesh_terms: D000328:Adult; D000368:Aged; D001025:Aortitis / Q000000981:diagnostic imaging*; D016022:Case-Control Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18