[NMR tomography in urology. Principles--technics--risks--areas of use].

NMR tomography is a new imaging method based on nuclear magnetic resonance. It is possible to obtain sectional views of the human body in all three planes without ionizing radiation. NMR can differentiate soft tissue better than CT, and large blood vessels can be simultaneously evaluated without using contrast medium. The pathological process could be imaged exactly in every examination. Due to the lack of image clarity caused by breathing movement, NMR is not superior to CT when using contrast medium in the epigastrium. Calculation of relaxation times T1 and 2 shows clear differences between tumor and normal tissue. However, contrary to initial expectations. NMR did not permit a type-specific diagnosis to be made. Three-dimensional images improve the process of staging tumors, especially in the retroperitoneal space and in the pelvis. As with CT, metastatic lymph nodes can only be demonstrated when they have reached a size of at least 1 cm. Further studies will be necessary to evaluate the validity of this new imaging method.