title: Positron emission tomography (PET) used to image subclinical inflammation associated with ulcerative colitis (UC) in remission.
abstract: BACKGROUND
  Positron emission tomography (PET) using 18-fluorodeoxyglucose (18-FDG) is a noninvasive, functional imaging modality most often used to assess cancer. The aim of this study was to perform PET/computed tomography (CT) on patients with quiescent ulcerative colitis (UC) to understand the limits of this technology for assessing inflammatory activity.
  
  
  METHODS
  We identified patients diagnosed with UC in a strictly defined remission state. PET/CT was performed in standard fashion, using approximately 10 mCi of 18-FDG with a 60-minute uptake delay. Uptake in each of 4 colonic segments (recto-sigmoid [r-s], descending, transverse, and ascending), and distal small bowel were scored on a 3-point scale (0 = no uptake or uptake <or=liver; 1 = uptake somewhat >liver; 2 = uptake much greater than liver).
  
  
  RESULTS
  Ten patients participated in this study, 6 male. Eight had pancolitis, 1 had extensive colitis, and 1 had procto-sigmoiditis, with a median disease duration was 32 years. A PET scan was performed mean 37 days after endoscopy. Six patients had no increased 18-FDG uptake, 3 had increased uptake in the r-s region, 1 patient with r-s uptake also had ascending colon uptake, and 1 had ileal uptake with no colonic signal.
  
  
  CONCLUSIONS
  In this study, PET demonstrated inflammatory activity in the colon despite negative endoscopic, histologic, and symptom assessment. This has important implications in the understanding of UC disease quiescence. Further exploration of this highly sensitive modality should be performed.
authors.affiliation: Inflammatory Bowel Disease Center, Department of Medicine, University of Chicago Medical Center, Chicago, IL 60637, USA. drubin@uchicago.edu
authors.forename: David T
authors.initials: DT
authors.lastname: Rubin
authors.forename: Bonnie L
authors.initials: BL
authors.lastname: Surma
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Gavzy
authors.forename: Kerry M
authors.initials: KM
authors.lastname: Schnell
authors.forename: Alana P
authors.initials: AP
authors.lastname: Bunnag
authors.forename: Dezheng
authors.initials: D
authors.lastname: Huo
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Appelbaum
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003093:Colitis, Ulcerative / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007249:Inflammation; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals; D012074:Remission Induction; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18