The prognostic value, in active ulcerative colitis, of an increased intensity of colonic perivisceral fat signal on magnetic resonance imaging with ferumoxil

OBJECTIVE: In active ulcerative colitis (UC), magnetic resonance imaging (M RI) with ferumoxil, a superparamagnetic oral contrast agent, accurately eva luates, in our experience, the increased wall thickness and frequently show s a stronger perivisceral fat signal intensity (PFSI). The aim of our study was to evaluate the clinical significance of these MRI findings in active UC. METHODS: Twenty-four consecutive patients affected by moderate pancolitis w ere enrolled. At entry, each patient underwent MRI with ferumoxil to evalua te wall thickness and PFSI. Two groups of patients were individuated: group A (increased PFSI) and group B (normal PFSI). After obtaining remission, t he number of relapses and, at each flare-up, the clinical activity index (C AI) were evaluated in all patients in a 2-yr follow-up period. The mean CAY was calculated at the end of the follow-up in each patient. Where there wa s colectomy, a complete histological examination of the colon was performed . RESULTS: PFSI was increased in 16 patients (group A) and was normal in the remainder (group B). There was a significant difference of wall thickness, number of relapses/yr, and mean CAI between the two groups of patients. No difference was observed with regard the duration of disease. Six patients o f group A and no patient of group B underwent colectomy. The histological e valuation showed an increased thickness of the entire colonic wall with sig nificant changes of the perivisceral fat structures. CONCLUSIONS: An increased PFSI on MRI identifies a group of UC patients wit h an increased wall thick:ness, significantly higher than that observed in patients with normal PFSI and seems to be related to a poor prognosis. (C) 2001 by Am. Cell. of Gastroenterology.