Value of ¹⁸F-FDG PET/CT in the diagnosis of inflammatory bowel diseases

Objective: To explore the diagnostic value of ¹⁸F-FDG PET/CT in the inflammatory bowel diseases (IBD). Methods: The clinicopathological data of 75 patients(46 males, 29 females; average age 38 years) with IBD confirmed by colonoscopy from March 2010 to March 2014 were reviewed retrospectively. Among the 75 patients, 30 were with ulcerative colitis (UC) and 45 were with Crohn's disease (CD). All underwent whole-body ¹⁸F-FDG PET/CT imaging. Enteroscope and CRP examination were performed within 1 week before or after PET/CT imaging. The results of ¹⁸F-FDG PET/CT were compared with those of located CT and enteroscope (χ², t tests). Linear correlation analysis was used to analyze the relationship between CRP and the SUV_max of lesions presented in IBD. Results: (1) ¹⁸F-FDG PET/CT accurately detected 65 patients with IBD, while located CT diagnosed 55 patients with IBD. The diagnostic sensitivities were significantly different: 86.7%(65/75) vs 73.3%(55/75), χ² = 4.167, P < 0.05. (2) Among 65 patients with positive results in ¹⁸F-FDG PET/CT, lesions were consistent with those detected by endoscopy in 33(33/75, 44.0%) patients. Results of the 2 methods in 24 patients (24/75, 32.0%) were not completely same, those in 8 patients (8/75, 10.7%) were totally different. ¹⁸F-FDG PET/CT detected 145 lesions, while enteroscope only detected 119 lesions. Diffuse high FDG uptake was shown in intestinal wall in 40 of 65 patients, and mild mucosa injury was showed by enteroscope in 18 patients(45.0%, 18/40). (3) Forty-eight of 65 patients detected by PET/CT were proven clinically to be in active stage, and the rest were in stable stage. The SUV_max of active stage group (8.31 ± 4.21) was significantly higher than that of the chronic stage group (6.36 ± 3.15; t = 2.033, P < 0.05) .There was a linear correlation between CRP and SUV_max of patients in active stage(r = 0.453, P < 0.01). Conclusions: ¹⁸F-FDG PET/CT is helpful to assess the activity of IBD and may serve as a supplementary diagnosing tool to detect the lesions under the epithelium of bowel, which are often false-negative by enteroscope. (authors)