title: PET/CT colonography in patients with colorectal polyps: a feasibility study.
abstract: OBJECTIVE
  To examine: (1) the feasibility of PET/CT colonography (PET/CTc) in patients with colorectal polyps; (2) the impact of metabolic information on CTc interpretation and, conversely, the impact of morphological information on PET characterisation of focal colorectal uptake.
  
  
  METHODS
  Ten patients with colorectal polyps underwent PET/CTc, followed within 3 h by therapeutic conventional colonoscopy (CC). A radiologist and a nuclear medicine physician analysed the PET/CTc images. The agreement of morphological and metabolic information in the colon and rectum was evaluated. The sensitivity and specificity of PET, CT and PET/CT were calculated for colorectal polyps.
  
  
  RESULTS
  Seventeen polypoid lesions were identified at CC: six< or =5 mm, six between 6 and 9 mm, and five > or =10 mm (four hyperplastic polyps, 11 tubular adenomas, one adenocarcinoma and one submucosal lipoma). A total of 20 scans (supine and prone) were performed in the ten patients: the agreement of morphological and metabolic information was excellent in 17 scans, good in two and moderate in one. PET/CTc showed a sensitivity of 91% for lesions > or =6 mm and a specificity of 100%. The metabolic information did not disclose any further polyps missed on CTc. The morphological information permitted correct classification of all eight instances of focal radiotracer uptake.
  
  
  CONCLUSIONS
  PET/CTc is a feasible study. Adding a colonographic protocol to PET/CT images seems to allow correct characterisation of all cases of colorectal focal radiotracer uptake. The metabolic information does not seem to increase the accuracy of CTc.
authors.affiliation: IBB CNR, Naples, Italy. pierpamainenti@hotmail.com
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Mainenti
authors.forename: Barbara
authors.initials: B
authors.lastname: Salvatore
authors.forename: Dario
authors.initials: D
authors.lastname: D'Antonio
authors.forename: Teresa
authors.initials: T
authors.lastname: De Falco
authors.forename: Giovanni Domenico
authors.initials: GD
authors.lastname: De Palma
authors.forename: Francesco Paolo
authors.initials: FP
authors.lastname: D'Armiento
authors.forename: Luigi
authors.initials: L
authors.lastname: Bucci
authors.forename: Leonardo
authors.initials: L
authors.lastname: Pace
authors.forename: Marco
authors.initials: M
authors.lastname: Salvatore
mesh_terms: D000328:Adult; D000368:Aged; D003111:Colonic Polyps / Q000175:diagnosis*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D012007:Rectum / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*