Magnetic resonance imaging with ferumoxil, a negative superparamagnetic oral contrast agent, in the evaluation of ulcerative colitis.

Objective: The introduction of new oral contrast agents that enhance image quality has increased the importance of magnetic resonance imaging (MRI) in the management of ulcerative colitis. The aim of our study was to investigate the usefulness of a new negative superparamagnetic oral contrast (ferumoxil) alone or in association with gadolinium i.v. in the assessment of the disease.
Methods: Twenty-eight patients with clinically active ulcerative colitis and 10 control subjects entered the study. In each patient a clinical, endoscopic, histological, and MRI evaluation was performed. In particular, in 14 patients affected by ulcerative colitis (group A) and in five controls, magnetic resonance images were acquired 1 h after the oral administration of 900 ml of ferumoxil, while the remaining 14 patients (group B) and five controls were submitted to double-contrast MRI (ferumoxil and gadolinium). In both groups, wall thickness, length of affected bowel segments, and, in group B, also percent contrast enhancement were calculated.
Results: The comparison of endoscopic and MRI extent of disease was statistically significant. Wall thickness and, in group B, also percent contrast enhancement were significantly correlated with clinical and endoscopic activities. In each group wall thickness was significantly different in the activity phases of the disease.
Conclusions: MRI with negative superparamagnetic oral contrast is comparable to endoscopy in the assessment of ulcerative colitis. The double-contrast imaging does not provide more information than single oral contrast, so we concluded that the latter is preferable in the follow-up of the disease and in patients unable or with a poor compliance to undergo endoscopy.