Low-dose 18F-FDG PET/CT enterography: improving on CT enterography assessment of patients with Crohn disease

J Nucl Med. 2010 Dec;51(12):1841-8. doi: 10.2967/jnumed.110.080796. Epub 2010 Nov 15.


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.

Conclusion: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Colonoscopy
  • Contrast Media
  • Crohn Disease / diagnostic imaging*
  • Crohn Disease / pathology
  • False Negative Reactions
  • False Positive Reactions
  • Female
  • Fluorodeoxyglucose F18* / administration & dosage
  • Humans
  • Image Interpretation, Computer-Assisted
  • Intestines / pathology
  • Male
  • Middle Aged
  • Pilot Projects
  • Positron-Emission Tomography / methods*
  • Prospective Studies
  • Radiometry
  • Radiopharmaceuticals* / administration & dosage
  • Tomography, Emission-Computed / methods*
  • Young Adult


  • Contrast Media
  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18