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

Abstract

In active ulcerative colitis (UC), magnetic resonance imaging (MRI) with ferumoxil, a superparamagnetic oral contrast agent, accurately evaluates, in our experience, the increased wall thickness and frequently shows 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. Twenty-four consecutive patients affected by moderate pancolitis were enrolled. At entry, each patient underwent MRI with ferumoxil to evaluate wall thickness and PFSI. Two groups of patients were individuated: group A (increased PFSI) and group B (normal PFSI). After obtaining remission, the number of relapses and, at each flare-up, the clinical activity index (CAI) were evaluated in all patients in a 2-yr follow-up period. The mean CAI was calculated at the end of the follow-up in each patient. Where there was colectomy, a complete histological examination of the colon was performed. 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 of group A and no patient of group B underwent colectomy. The histological evaluation showed an increased thickness of the entire colonic wall with significant changes of the perivisceral fat structures. An increased