title: Factors Associated with Diffusely Increased Splenic F-18 FDG Uptake in Patients with Cholangiocarcinoma.
abstract: OBJECTIVE
  Although diffuse splenic (18)F-fluorodeoxyglucose (F-18 FDG) uptake exceeding hepatic activity, is considered abnormal, its clinical significance is rarely discussed in the literature. The aim of this study was to determine the contributing factors causing diffusely increased splenic FDG uptake in patients with cholangiocarcinoma.
  
  
  METHODS
  From January 2010 to March 2013, 140 patients (84 men, 56 women) were enrolled in this study. All patients had been diagnosed with cholangiocarcinoma and underwent F-18 FDG positron emission tomography/computed tomography (PET/CT) for the pretreatment staging work up. Clinical records were reviewed retrospectively. Various hematological parameters, C-reactive protein (CRP) level, CEA, CA19-9, pancreatic enzymes and liver function tests were conducted within 2 days after the F-18 FDG PET/CT study.
  
  
  RESULTS
  Diffuse splenic uptake was observed in 23 patients (16.4%). Of those, 19 patients (82.6%) underwent endoscopic retrograde cholangiopancreastography (ERCP) 7 days before F-18 FDG PET/CT. The CRP level (p < 0.001) and white blood cell count (p = 0.023) were significantly higher in the group of patients with diffuse splenic FDG uptake. The hemoglobin (p < 0.001) and the hematocrit (p < 0.001) were significantly lower in patients with diffuse splenic FDG uptake. Pancreatic enzymes, liver function test results, and tumor markers were not significantly different between the patients who did or did not have diffusely increased splenic FDG uptake. The significant factors for diffuse splenic F-18 FDG uptake exceeding hepatic F-18 FDG uptake on multivariate analysis included: performing ERCP before F-18 FDG PET-CT (odds ratio [OR], 77.510; 95% CI, 7.624-132.105), and the presence of leukocytosis (OR, 12.436; 95% CI, 2.438-63.445) or anemia (OR, 1.211; 95% CI, 1.051-1.871).
  
  
  CONCLUSIONS
  In conclusion, our study demonstrated that concurrent inflammation could be associated with diffusely increased splenic FDG uptake. We suggest that performing ERCP before F-18 FDG PET/CT could cause acute inflammation which may induce splenic FDG activity.
authors.affiliation: Department of Nuclear Medicine, Pusan National University Hospital, Busan, Republic of Korea.
authors.forename: Keunyoung
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Pusan National University Hospital, Busan, Republic of Korea ; Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea ; Department of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital, 1-10, Ami-dong, Seo-gu Busan, Republic of Korea 602-739.
authors.forename: Seong-Jang
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Pusan National University Hospital, Busan, Republic of Korea ; Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea.
authors.forename: In-Joo
authors.initials: IJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Pusan National University Hospital, Busan, Republic of Korea.
authors.forename: Dong Uk
authors.initials: DU
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Pusan National University Hospital, Busan, Republic of Korea.
authors.forename: Heeyoung
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Pusan National University Hospital, Busan, Republic of Korea.
authors.forename: Sojung
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Pusan National University Hospital, Busan, Republic of Korea.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Ahn
keywords: Cholangiocarcinoma; ERCP; FDG uptake; PET/CT; Spleen