Acute colitis: differential diagnosis using multidetector CT.

AIM: To investigate the utility of multidetector CT (MDCT) in helping to establish the underlying cause of acute colitis.

METHODS AND MATERIALS: All patients who had acute colitis with a well-identified cause and underwent abdomen 64-MDCT were included in the study. MDCT images were retrospectively analysed in a blinded fashion and the CT findings were correlated with the eventual aetiological diagnosis.

RESULTS: The study population included 105 patients. Acute colitis was related to inflammatory bowel disease in 43 cases. MDCT was used to identify six relevant signs of inflammatory colitis: the "comb" sign (p < 0.001), enlarged lymph nodes (p < 0.001), abscess (p = 0.026), fibro-fatty infiltration (p = 0.007), small bowel involvement (p < 0.001), and the absence of an "empty colon" sign (p = 0.045). Multivariate logistic regression analysis identified three independent signs of inflammatory colitis: the "comb" sign, small bowel involvement, and enlarged lymph nodes. Acute colitis was related to bacterial infection in 35 cases. Five signs were significantly associated with infectious colitis: continuous distribution (p = 0.020), an "empty colon" sign (p = 0.002), absence of fat stranding (p = 0.013), and absence of a "comb" sign (p = 0.010) and absence of enlarged lymph nodes (p = 0.035). Multivariate analysis identified three independent signs: the "empty colon" sign and absence of fat stranding and of a "comb" sign. The remaining causes were ischaemic colitis (n = 21) and drug-related colitis (n = 6). MDCT examination provided five relevant signs of ischaemic colitis: fat stranding (p = 0.002), discontinuous distribution (p < 0.001), and absence of enlarged lymph node (p < 0.001), a "comb" sign (p = 0.006) and small bowel involvement (p = 0.037).

CONCLUSIONS: MDCT provides certain suggestive signs that may be helpful in distinguishing the underlying aetiological cause of acute colitis.