title: High (18)F-FDG uptake in urinary calculi on PET/CT: An unrecognized non-malignant accumulation.
abstract: OBJECTIVE
  To assess the high (18)F-fluorodeoxyglucose ((18)F-FDG) uptake in urinary calculi on positron-emission tomography/computed tomography (PET/CT).
  
  
  METHODS
  In this study, (18)F-FDG PET/CT examinations were retrospectively reviewed from November 2013 to February 2016 in a single center, and patients with high (18)F-FDG uptake in urinary calculi were identified. The following data were collected from each patient, including age, sex, primary disease, method to verify the urinary calculus, and imaging characteristics of the calculus.
  
  
  RESULTS
  A total of 2758 PET/CT studies (2567 patients) were reviewed, and 52 patients with urinary calculi were identified, in which 6 (11.5%, 6/52) patients (5 males, 1 female, age 34-73 years, median age 60.5 years) demonstrated high (18)F-FDG uptake in the urinary calculi. Among the 6 patients, 3 patients had bladder calculi, 2 patients had renal calculi, and 1 patient had both bladder and renal calculi. The size of the urinary calculi varied from sandy to 19mm on CT. The maximal Hounsfield units of the calculi ranged from 153 to 1078. The SUVmax of the calculi on the routine PET/CT scan ranged from 11.7 to 143.0. Delayed PET/CT scans were performed on 4 patients, which showed the calculi SUVmax increasing in 2 patients, while decreasing in the other 2 patients. One patient with bladder calculus underwent a follow-up PET/CT, which showed enlargement of the calculus as well as the increased SUVmax.
  
  
  CONCLUSIONS
  This study shows an uncommon high (18)F-FDG uptake in urinary calculi. Recognition of this non-malignant accumulation in urinary calculi is essential for correct interpretation of PET/CT findings.
authors.affiliation: Department of Nuclear Medicine, Peking University First Hospital, Beijing 100034, China. Electronic address: fuzhanli2002@163.com.
authors.forename: Zhanli
authors.initials: Z
authors.lastname: Fu
authors.affiliation: Department of Nuclear Medicine, Peking University First Hospital, Beijing 100034, China.
authors.forename: Ziao
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Nuclear Medicine, Zhejiang Jinhua Guangfu Hospital, Jinhua 321000, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Nuclear Medicine, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Nuclear Medicine, Peking University First Hospital, Beijing 100034, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Medical Imaging Services, Good Samaritan Hospital, Central Islips, NY 11722, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007669:Kidney Calculi / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012189:Retrospective Studies; D001744:Urinary Bladder Calculi / Q000000981:diagnostic imaging / Q000378:metabolism; D014545:Urinary Calculi / Q000000981:diagnostic imaging / Q000378:metabolism*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: (18)F-Fluorodeoxyglucose; Computed tomography; Positron emission tomography; Urinary calculus