title: Ascites metabolism measurement enhanced the diagnostic value and accuracy of prognostic evaluation in 18F-FDG PET/CT studies in malignant ascites patients.
abstract: OBJECTIVE
  This study aimed to evaluate the role of ascites metabolism measurement in (18)F-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (CT) for auxiliary diagnosis and prognostic evaluation of malignant ascites.
  
  
  METHODS
  This was a retrospective study on 55 patients, including 36 with malignant ascites and 19 with benign ascites of undetermined origin, before they underwent their first (18)F-FDG PET/CT scan. The χ(2) -test was used to compare the diagnostic efficiencies among (18)F-FDG PET/CT ascites metabolism measurement, tumor localization, and ascites cytology examination. The standard uptake values of ascites and of the normal liver were measured, respectively, and their ratio, denoted as T/NT, was calculated for each patient. The receiver-operating characteristic curve was used to analyze the diagnostic efficiency of the ascites T/NT, ascites carcinoembryonic antigen, ascites CA1(25), and ascites CA(199), and the linear regression was used to analyze the relationship between the ascites T/NT and the survival time of patients.
  
  
  RESULTS
  The metabolic level of malignant ascites was high. The sensitivity and accuracy of ascites metabolism measurement were higher than those of ascites cytology examination (χ(2) =6.98, 4.58; all P's<0.05). The specificity of ascites metabolism measurement was higher than that of (18)F-FDG PET/CT tumor localization (χ(2) =5.70, P<0.05). The T/NT value of malignant ascites (0.68 ± 0.17) was higher than that of benign ascites (0.38 ± 0.10) (t=7.21, P<0.05). The area under the receiver-operating characteristic curve of ascites T/NT was larger than those of ascites carcinoembryonic antigen, CA(125), and CA(199). There was a negative correlation between the ascites T/NT and the survival of patients with malignant ascites (r=-0.647, P<0.01).
  
  
  CONCLUSIONS
  Ascites metabolism measurement has an important auxiliary diagnostic value in (18)F-FDG PET/CT for ascites patients. The ascites T/NT may be a good index for prognostic evaluation of malignant ascites.
authors.affiliation: Department of Nuclear Medicine, Qilu Hospital, Shandong University, Shandong, People's Republic of China.
authors.forename: Xian-jun
authors.initials: XJ
authors.lastname: Li
authors.forename: Feng-qi
authors.initials: FQ
authors.lastname: Li
authors.forename: Jian-kui
authors.initials: JK
authors.lastname: Han
authors.forename: Zhi-hua
authors.initials: ZH
authors.lastname: Zhao
authors.forename: Zhen-guo
authors.initials: ZG
authors.lastname: Song
authors.forename: Xue-zhi
authors.initials: XZ
authors.lastname: Dai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001201:Ascites / Q000150:complications* / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009369:Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18