title: Clinical significance of incidental focal colorectal (18)F-fluorodeoxyglucose uptake: our experience and a review of the literature.
abstract: OBJECTIVE
  The aims of the present study were: (i) to evaluate the focal incidental colorectal uptake of (18)F-fluorodeoxyglucose ([(18)F]FDG) and to correlate it with colonoscopy and histological findings; (ii) to evaluate the relationship between the presence/absence of neoplastic disease and clinical data and the anatomical site of [(18)F]FDG uptake; and (iii) to compare our results with those reported for incidental colorectal uptake of [(18)F]FDG in the literature and those obtained from various screening programmes for colorectal cancer.
  
  
  METHODS
  The database of 6000 patients referred for [(18)F]FDG positron emission tomography/computed tomography (PET-CT) to our centre was retrospectively reviewed for incidental colorectal uptake of [(18)F]FDG. Patients with focal uptake were selected and the aetiology of PET findings was verified with a subsequent colonoscopy and histopathological analysis when available.
  
  
  RESULTS
  Incidental colorectal uptake of [(18)F]FDG was seen in 144 (2.4%) patients, of whom 64 (1.1%) had focal uptake; 48 out of these 64 patients underwent colonoscopy, which showed malignant tumours in 12 (25%), premalignant lesions in 19 (40%), non-neoplastic lesions in six (12%) and lesions not confirmed by colonoscopy in 11 (23%). Our data agreed with previously published data. Statistical analysis did not show any significant relationship between the presence/absence of neoplastic disease and patient sex or age, type of primary disease and anatomical site of [(18)F]FDG uptake. Comparing our data with various screening programmes, a significant difference was found only with series in which colonoscopy was performed in patients at high risk for colorectal cancer.
  
  
  CONCLUSIONS
  Focal incidental colorectal uptake of [(18)F]FDG is observed in about 1% of PET/CT studies and carries a high risk of neoplastic disease. A PET-CT report should suggest colonoscopy when abnormal findings are reported.
authors.affiliation: Institute of Nuclear Medicine, Università Cattolica del Sacro Cuore, Rome, Italy. giorgiomednuc@libero.it
authors.forename: G
authors.initials: G
authors.lastname: Treglia
authors.forename: M L
authors.initials: ML
authors.lastname: Calcagni
authors.forename: V
authors.initials: V
authors.lastname: Rufini
authors.forename: L
authors.initials: L
authors.lastname: Leccisotti
authors.forename: G M
authors.initials: GM
authors.lastname: Meduri
authors.forename: M G
authors.initials: MG
authors.lastname: Spitilli
authors.forename: D P
authors.initials: DP
authors.lastname: Dambra
authors.forename: A M
authors.initials: AM
authors.lastname: De Gaetano
authors.forename: A
authors.initials: A
authors.lastname: Giordano
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D003111:Colonic Polyps / Q000000981:diagnostic imaging / Q000473:pathology; D003113:Colonoscopy; D004239:Diverticulitis, Colonic / Q000000981:diagnostic imaging; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D033162:Incidental Findings; D007890:Leiomyosarcoma / Q000000981:diagnostic imaging* / Q000473:pathology; D008223:Lymphoma / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18