Contribution of oral magnetic particles in MR imaging of the abdomen with spin-echo and gradient-echo sequences

An open phase III clinical trial of the oral contrast agent OMP (oral magnetic particles) was performed in 35 patients undergoing abdominal magnetic resonance (MR) imaging at 1.5 T with axial spin-echo and gradient-echo sequences. The diagnostic efficacy of OMP was examined by comparing pre-and postcontrast images. Bowel loops and abdominal organs were more easily recognizable after OMP ingestion, and the general quality of the images was improved because of fewer bowel-related artifacts. The diagnostic value of the postcontrast abdominal MR examination was superior or equal to that of the precontrast study, and additional information was obtained in 44% of the cases. Postcontrast gradient-echo sequences increased confidence in the MR examination in 18% of cases. OMP was well tolerated and increased the quality and amount of diagnostic information acquired during the examination. Gradient-echo imaging was found to be a useful complement, but the need for a reduction in susceptibility artifacts was apparent and indicates that a decrease in TE or the use of rapid spin-echo sequences might be advantageous.