[Magnetic resonance imaging of cancer of the rectum]

MRI (Magnetic Resonance Imaging) has become a major diagnostic method, in many fields. Its results, in the pre-operative evaluation of rectal cancers, are presented here. The possibilities of determining by MRI, parietal extension, peri-rectal fat invasion, extension to adjoining organs and nodes, are specified. Then, the contribution of MRI to the measurement of the distance between the lower pole of the tumor and the levator muscles plane, is evaluated.