Magnetic resonance imaging and computer tomography of acute spinal cord trauma. Spinal cord lesions are not detectable on roentgenograms and computed tomography (CT) scans. Magnetic resonance images (MRIs) are able to make soft-tissue lesions visible. Interpretations of MRIs, CT scans, and roentgenograms were compared in 25 patients and three postmortem specimens with spinal cord injuries. In 14 patients and one specimen with normal roentgenograms and CT scans, the MRI demonstrated ten soft-tissue injuries as minimal displacement of the vertebral bodies or as a high signal intensity in the disc space, indicating a hematoma. Seven of the ten patients demonstrating soft-tissue injuries also had an intramedullary lesion, while in five of the 15 patients with normal CT scans, only a medullary lesion was present on MRI. In 11 patients and two postmortem specimens, fractures were seen on roentgenograms and CT scans. In these patients, the CT was superior to the MRI in detecting small bony fragments, but the medullary lesions were visible only on the MRIs. An intramedullary low signal intensity corresponded to macroscopically visible hemorrhages in the three postmortem specimens. The MRI provided important information in patients with neurologic deficits. No obvious pathologic changes were evident on the roentgenograms and CT scans. The MRI also demonstrated intramedullary and extramedullary soft-tissue lesions and was useful in establishing a diagnosis and in choosing appropriate therapy. CT, on the other hand, was superior in detecting small bony fragments and fracture lines. 