Background: Although Crohn disease (CD) can affect the entire alimentary tract, the proportion of patients with small bowel inflammation proximal to the terminal ileum is still unclear. Magnetic resonance imaging (MRI) combined with smallbowel enteroclysis can detect inflammatory lesions of the small bowel. Hence, we applied MR enteroclysis to assess the percentage of patients with small bowel inflammation proximal to the terminal ileum among patients with CD and abdominal pain. Methods: Twenty five consecutive patients with low, active CD of the colon and/or terminal ileum and episodes of abdominal pain were examined by both MR enteroclysis and conventional enteroclysis. The findings of MR enteroclysis were compared with endoscopic and histological results in the terminal ileum and conventional enteroclysis in the small bowel proximal to the terminal ileum. Results: In 13 of the 25 patients, inflammation of the small bowel proximal to the terminal ileum was shown by MR enteroclysis, whereas in only 4 of the 25 patients, signs of inflammation of the small bowel proximal to the terminal ileum were shown by conventional enteroclysis, all of which were demonstrated by MR enteroclysis. MR enteroclysis confirmed the findings in 22 of 25 patients in whom endoscopy and histology had shown inflammation (16 of 18) or no inflammation (6 of 7) of the terminal ileum. Conclusion: In symptomatic patients with CD even of low activity, inflammation of the small bowel proximal to the terminal ileum is frequent. Background: Although Crohn disease (CD) can affect the entire alimentary tract, the proportion of patients with small bowel inflammation proximal to the terminal ileum is still unclear. Magnetic resonance imaging (MRI) combined with small bowel enteroclysis can detect inflammatory lesions of the small bowel . Therefore, we applied MR enteroclysis to assess the percentage of patients with small bowel inflammation proximal to the terminal ileum among patients with CD and abdominal pain. Methods: Twenty five consecutive patients with low, active CD of the colon and / or terminal ileum and episodes of abdominal pain were examined by both MR enteroclysis and conventional enteroclysis. The findings of MR enteroclysis were compared with endoscopic and histological results in the terminal ileum and conventional enteroclysis in the small bowel proximal to the terminal ileum. Results: In 13 of the 25 patients, inflammation of the small bowel proximal to the terminal ileum was shown by MR enteroclysis, w hereas in only 4 of the 25 patients, signs of inflammation of the small bowel proximal to the terminal ileum were shown by conventional enteroclysis, all of which were demonstrated by MR enteroclysis. MR enteroclysis confirmed the findings in 22 of 25 patients in whom endoscopy and histology had shown inflammation (16 of 18) or no inflammation (6 of 7) of the terminal ileum. Conclusion: In symptomatic patients with CD even of low activity, inflammation of the small bowel proximal to the terminal ileum is frequent.