A COMPARATIVE-STUDY BETWEEN GD-DTPA AND ORAL MAGNETIC PARTICLES (OMP)AS GASTROINTESTINAL (GI) CONTRAST AGENTS FOR MRI OF THE ABDOMEN

In the present study we compared two gastrointestinal contrast agents - Gd-DTPA, a positive signal, and oral magnetic particl es (OMP), a ne gative signal contrast agent - in patients who were referred for MR im aging of the abdomen. Altogether 60 patients were examined with the fo rmer and 28 patients with the latter contrast before and after the adm inistration of contrast media. Gd-DTPA was given either per os or per rectum. In comparing the results, it was shown that the diagnostic acc uracy of postcontrast MRI in both groups was more or less similar to C T but much higher as compared with plain MRI. In the OMP series, first the contrast between the GI-filled lumen and the surrounding fat was much superior to that of the Gd-DTPA and, second, there was no evidenc e of any artifacts from bowel motion. However, the overall accuracy of the Gd-DTPA group was better compared with that of the OMP group. Thi s was due to underfilling of the distal bowel because the OMP in those patients was administered only per os. Finally, Gd-DTPA had a more pl easant taste and fewer side effects. It is concluded that both contras t media are suitable for the upper abdomen because the results are com parable, whereas for the lower abdomen Gd-DTPA is superior because it can be used from both routes.