Superparamagnetic particles as gastrointestinal contrast agent in magnetic resonance imaging of lower abdomen

Negative gastrointestinal contrast enhancement can be achieved by oral administration of superparamagnetic particles. Their feasibility for the MR imaging of the female pelvis and lower abdomen was evaluated in studies on 32 follow-up patients with treated gynaecologic cancer. All the applied doses (0.2-1.0 mg particles/ml given in a volume of 600-800 ml) of contrast medium decreased the intraluminal signal. However, there was unpredictable individual variation in segmental distribution, and in some cases only a limited contrast effect was obtained. Image distortion was detected when the applied particle concentration exceeded 0.5 mg/ml, especially of the sagittal sections.