Fig. 6

A 69-year-old female with known ulcerative colitis investigated with WE-MDCT using limited bowel preparation during an acute disease exacerbation. The rectum and sigmoid colon show circumferential mural thickening (arrowheads) with a “water halo sign” appearance (a) and associated perirectal fat proliferation (*). The upstream colon appears well-distended with normal mural thickness and some endoluminal faecal residues (c, d). Findings are consistent with left-sided acute, severe colitis and allow obviating the need for endoscopy