P312. Acutec: differential diagnosis using computed tomography
L. Plastaras1, S. Koch2, L. Vuitton1, E. Nedeva3, V. di Martino4, E. Delabrousse3, 1University Hospital of Besançon, Gastroenterology, Besançon, France, 2University Hospital of Besançon, Gastroenterology, Besançon, France, 3University Hospital of Besançon, Radiology, Besançon, France, 4University Hospital of Besançon, Hepatology, Besançon, France
Etiological diagnosis of acute colitis (AC) is difficult, requiring bacteriologic, endoscopic, histopathological and outcome examinations. The aim of this work was to investigate the performance of Computed tomography (CT) to identify the cause of AC and study a new sign, the flat colon sign.
This monocentric retrospective observational study included all consecutive patients admitted to the Gastroenterology department of the University Hospital of Besançon from January 2006 to September 2010. All patients had AC with a clearly identified cause and all had had an abdominal CT scan. CT were retrospectively analyzed in a blinded test and result was then compaird with final etiological diagnosis. We studied the literature for all CT signs and we described a sign, not previously described in the literature: the flat colon sign. It was defined by a complete emptiness of the colonic lumen.
During the study period, 1452 patients were hospitalized for AC. Of them, 1247 were excluded because they didn't undergo CT, or the cause of colitis remained uncertain. Study final population included 105 patients. CT identified 6 signs of inflammatory colitis (n = 43): comb sign, lymph nodes, abscesses, fibrofatty infiltration, involvement of the small bowel, and absence of flat colon sign. Multivariate analysis identified 3 signs: comb sign (OR = 15.16, [95% CI: 2.19–105.10], p = 0.006), small bowel involvement (OR = 6.35, [95% CI: 1.11–36.29], p = 0.037), and lymph nodes (OR = 16.66, [95% CI: 4.94–56.21], p < 0.001. Five signs were associated with infectious colitis (n = 35): continuous distribution, flat colon sign, fat stranding, and absence of comb sign and lymph nodes. Multivariate analysis identified 3 signs: flat colon sign (OR = 12.32 [95% CI: 1.68–90.15], p = 0.013), absence of fat stranding (OR = 3.85, [95% CI: 1.30–11.11], p = 0.014), and of comb sign (OR = 5.88 [95% CI: 1.18–33.33], p = 0.031). Five signs were associated with ischemic colitis (n = 21): fat stranding infiltration, and absence of lymph node, continuous distribution, comb sign, and small bowel involvement. Given the small number of patients in the ischemic colitis group, no multivariate analysis was performed.
CT appears as a powerful tool to identify specific sign of each etiology of AC. CT is useful to distinguish inflammatory colitis from infectious colitis, particularly when considering the flat colon sign. A larger prospective study should be conducted to confirm these results.