title: Respiratory-gated ¹⁸F-FDG PET/CT for the diagnosis of liver metastasis.
abstract: OBJECTIVE
  To ascertain the role of respiratory-gated PET/CT with (18)F-fluorodeoxyglucose ((18)F-FDG) for accurate diagnosis of liver metastasis.
  
  
  METHODS
  Forty patients with suspected liver metastasis underwent conventional whole-body PET/CT scan initially, followed by respiratory-gated PET/CT scan covering the liver. Visual detectability (using a 5-point confidence scale), maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) of hepatic metastatic lesions were assessed for three data sets including ordinary whole-body (WB) scan, and non-respiratory-gated (nRG) and respiratory-gated (RG) scans. Results of enhanced CT and/or MRI, or clinical and radiological follow-up were used for reference.
  
  
  RESULTS
  Sixteen of the patients were found to have 53 metastatic lesions in the liver. Patient-based accuracy of WB, nRG, and RG was 92.5%, 95.0%, and 97.5%, respectively, with a lesion-based detection rate of 67.9%, 73.6%, and 73.6%, respectively. The average SUVmax of 34 liver metastatic lesions for WB, nRG, and RG was 6.60 ± 2.34, 7.19 ± 2.66, and 8.08 ± 3.24, respectively. SUVmax for RG was significantly higher than that for WB (p=0.0069). The average MTV of these 40 lesions for the three protocols was 5.32 ± 4.78 cm(3), 5.07 ± 4.73 cm(3), and 4.73 ± 4.67 cm(3), respectively. Among the three protocols, RG showed the best visual and quantitative evaluation for diagnosis of liver metastasis.
  
  
  CONCLUSIONS
  Respiratory-gated PET/CT allows more accurate identification of liver metastases than non-respiratory-gated PET/CT.
authors.affiliation: Department of Radiology of Kobe University School of Medicine, Kobe, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Suenaga
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kitajima
authors.forename: Hajime
authors.initials: H
authors.lastname: Aoki
authors.forename: Takashi
authors.initials: T
authors.lastname: Okunaga
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kono
authors.forename: Ippei
authors.initials: I
authors.lastname: Matsumoto
authors.forename: Takumi
authors.initials: T
authors.lastname: Fukumoto
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis* / Q000556:secondary*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008113:Liver Neoplasms / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D051598:Whole Body Imaging / Q000379:methods
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Liver metastasis; Metabolic tumor volume; PET/CT; Respiratory-gated; Standardized uptake value