title: Usefulness of dual-time point imaging after carbonated water for the fluorodeoxyglucose positron emission imaging of peritoneal carcinomatosis in colon cancer.
abstract: BACKGROUND
  Fluorodeoxygluose (FDG) positron emission/computed tomography (PET/CT) is emerging as a useful tool for the diagnosis of peritoneal carcinomatosis (PC). In this study, we assessed whether dual-time point imaging can improve the accuracy of FDG PET/CT for the diagnosis of PC after colon rectal cancer (CRC).
  
  
  METHODS
  Thirty-nine patients with past history of CRC were evaluated. Whole-Body PET/CT scan was acquired 1 hour after tracer injection. If one or more focal areas of increased FDG uptake (standardized uptake value, SUV max>2.5) were found in the abdomen, 1 L of carbonated water was orally administered to patients and a delayed scan of the abdominal region was acquired at 2 hours. The SUV max and the mean Delta (Δ) SUV were calculated. The scintigraphic results were compared with the results of colonoscopy and histology and with the clinical follow-up.
  
  
  RESULTS
  Thirteen out of the 39 patients did not show any significant area of FDG uptake at the whole-body scan. The remaining 26 patients showed an overall number of 27 sites of focal increased uptake, showing a mean SUV max of 6.5+3.3. Late scan of the abdomen showed vanishing spots in 11 cases. Focal and increasing FDG uptake was found in 15 subjects (for an overall number of 16 sites) with SUV max of 15.6+4 and mean Δ SUV of +26.3%±7.5%. In these cases, final diagnosis was PC in 10 patients (according to cytology or histology) and dysplastic polyp in 5 cases. No significant difference in Δ SUV was found between patients with PC and those with polypoid formations.
  
  
  CONCLUSIONS
  According to our results, dual-time point imaging after carbonated water may increase the accuracy of FDG PET/CT for the imaging of PC in patients affected by CRC.
authors.affiliation: Section of Nuclear Medicine, Santa Maria Goretti Hospital, Latina, Italy. lucfil@hotmail.com
authors.forename: Luca
authors.initials: L
authors.lastname: Filippi
authors.forename: Marco
authors.initials: M
authors.lastname: D'Arienzo
authors.forename: Francesco
authors.initials: F
authors.lastname: Scopinaro
authors.forename: Rita
authors.initials: R
authors.lastname: Salvatori
authors.forename: Oreste
authors.initials: O
authors.lastname: Bagni
mesh_terms: D000328:Adult; D000368:Aged; D061545:Carbonated Water / Q000008:administration & dosage*; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D010534:Peritoneal Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D061545:Carbonated Water; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18