Backwash ileitis in ulcerative colitis: Are there MR enterographic features that distinguish it from Crohn disease?
OBJECTIVE
To reveal the MR enterography (MRE) findings that distinguish backwash ileitis (BWI) from terminal ileitis due to Crohn's disease (CD) and to determine the usability of barium studies manifestations (ileocecal valve (ICV) gaping, terminal ileum dilatation) in MRE for the diagnosis of BWI in ulcerative colitis (UC) patients by pointing at the diagnostic performance of these imaging findings.


SUBJECTS-METHODS
The study population consisted of patients who were diagnosed as ulcerative colitis (UC), and underwent 1.5 T MRI between August 2011 and November 2017 to rule out small bowel involvement. The matched controls were comprised of Crohn's patients examined at the same period. Ileocolonoscopic/ histopathologic findings were accepted as reference standard. Mural/extramural changes in bowel segments, ileocecal valve (ICV) gaping, terminal ileum dilatation, restricted diffusion and anatomical extent of involvement were evaluated. In UC patients, the association between ICV gaping and terminal ileum dilatation and BWI was assessed by χ2 test. The diagnostic accuracy of these two findings in BWI was determined.


RESULTS
Sixty patients were included in the study (30 UC; 30 CD; mean age, 43 years in both groups). Ileocecal valve gaping and terminal ileum dilatation were significantly more frequent among BWI patients (p < 0.001) in UC. Patients with BWI showed a higher rate of pancolitis (88.9%). Median terminal ileum wall thickness was found to be significantly greater in patients with CD (p < 0.001).


CONCLUSION
In patients with definite diagnosis of UC, ileocecal valve gaping and terminal ileum dilatation suggest the development of BWI. However, these findings cannot be use to differentiate cause of terminal ileitis in patients with unconfirmed diagnosis and do not give reliable information about the causative factor of ileitis.
['Erden|Ayse|A|', 'Kuru Öz|Diğdem|D|', 'Gürsoy Çoruh|Ayşegül|A|', 'Erden|İlhan|İ|', 'Özalp Ateş|Funda Seher|FS|', 'Törüner|Murat|M|']
D000293:Adolescent D000328:Adult D000368:Aged D003093:Colitis, Ulcerative D003424:Crohn Disease D003937:Diagnosis, Differential D005260:Female D006801:Humans D007079:Ileitis D007082:Ileum D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D015203:Reproducibility of Results D012189:Retrospective Studies D055815:Young Adult
Backwash ileitis Ulcerative colitis MR enterography Crohn's disease