OVERHAUSER-ENHANCED MR-IMAGING (OMRI)

Purpose. To evaluate a new single-electron contrast agent for Overhaus er-enhanced MR imaging. The contrast agents that are currently availab le give enhancement factors that are too low to make the technique a v alid option for routine clinical use. Material and Methods. MR images were generated directly following the injection of the substance into rats. The MR scanner was operated at a main magnetic field of 0.01 T a nd equipped with a separate rf-transmitter tuned to the electron param agnetic resonance frequency of the contrast agent. Results. As expecte d, the images generated show a high level of enhancement in areas wher e the contrast agent was present, and a maximum enhancement of 60 time s the normal proton signal was obtained in the vascular area. The sign al-to-noise ratios in the images were superior to those previously att ained. Conclusion: The new contrast agent makes it possible to generat e MR images with both morphological and functional information at 0.01 T The signal-to-noise ratios found in the generated images were of th e same order as, or better than, those obtained with the standard clin ical routine.