title: Low-dose 18F-FDG PET/CT enterography: improving on CT enterography assessment of patients with Crohn disease.
abstract: The purpose of this study was to evaluate the diagnostic efficacy of low-dose, combined (18)F-FDG PET/CT enterography (PET/CTE), compared with CT enterography (CTE) alone, in the assessment of patients with Crohn disease.
  
  
  METHODS
  Thirteen patients with Crohn disease were prospectively enrolled in this pilot study and underwent abdominal-pelvic (18)F-FDG PET/CTE using neutral oral and intravenous contrast medium. The effective dose from PET/CTE was 17.7 mSv for the first 4 patients and 8.31 mSv for the last 9 patients. Six patients underwent surgical resection of the bowel, and 7 patients underwent colonoscopy with biopsies within 27 d (mean, 12 d) of PET/CTE. PET/CTE and CTE images were each visually assessed for Crohn disease involvement in 54 bowel segments with pathology correlation. Extraintestinal findings were recorded. A CTE severity score, maximum standardized uptake value (SUVmax), SUVmax ratio, simplified endoscopic score, and clinical parameters were correlated with pathology inflammation grade, on a per-patient basis and on a per-bowel-segment basis, using Spearman correlation.
  
  
  RESULTS
  In 3 (23.1%) of 13 patients, (18)F-FDG uptake using PET/CTE revealed active inflammation in a bowel segment not evident using CTE (n = 2) or revealed an enterocolic fistula missed with CTE (n = 1). Visual interpretation of both PET/CTE and CTE images detected the presence of disease in all bowel segments with more than mild inflammation (sensitivity, 100%; specificity, 89.7%; positive predictive value, 78.9%; and negative predictive value, 100%). Correlation to inflammation grade per patient was the strongest for the SUVmax ratio (0.735, P = 0.004) and SUVmax (0.67, P = 0.013), as compared with the CTE score (0.62, P = 0.024). Correlation with inflammation per bowel segment was higher for the CTE score (0.79, P < 0.0001) than the SUVmax ratio (0.62, P < 0.0001) or SUVmax (0.48, P < 0.0001). SUVmax correlated strongly with serum C-reactive protein (0.82, P = 0.023), but CTE score did not.
  
  
  CONCLUSIONS
  Low-dose (18)F-FDG PET/CTE, compared with CTE, may improve the detection and grading of active inflammation in patients with Crohn disease. PET/CTE also may reveal clinically significant findings, such as enterocolic fistula, not evident on PET or CTE alone.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. pshyn@partners.org
authors.forename: Paul B
authors.initials: PB
authors.lastname: Shyn
authors.forename: Koenraad J
authors.initials: KJ
authors.lastname: Mortele
authors.forename: Scott H
authors.initials: SH
authors.lastname: Britz-Cunningham
authors.forename: Sonia
authors.initials: S
authors.lastname: Friedman
authors.forename: Robert D
authors.initials: RD
authors.lastname: Odze
authors.forename: Robert
authors.initials: R
authors.lastname: Burakoff
authors.forename: Joel E
authors.initials: JE
authors.lastname: Goldberg
authors.forename: Mehmet
authors.initials: M
authors.lastname: Erturk
authors.forename: Stuart G
authors.initials: SG
authors.lastname: Silverman
mesh_terms: D000328:Adult; D000368:Aged; D003113:Colonoscopy; D003287:Contrast Media; D003424:Crohn Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007422:Intestines / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D011874:Radiometry; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D014055:Tomography, Emission-Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18