Comparison of myelography combined with postmyelographic spinal CT and MRI in suspected metastatic disease of the spinal canal.

Comparison between myelography (MY) and magnetic resonance imaging (MRI) was carried out in 36 patients with clinical suspicion of spinal cord or root compression due to metastatic disease in the spinal canal. In 3 patients metastatic lesions were visualized on MY but not on MRI, while there were no cases with a negative MY and a positive MRI. In 44% of the cases MY alone or combined with postmyelographic CT (pm-CT) showed a larger tumor extension than did MRI, while the opposite occurred in 25%. As for detection of bony metastases and tumor masses localized outside the spine there was no difference between MRI and MY + pm-CT. The results indicate that the choice between MRI and MY + pm-CT still can be based on the availability and quality of the procedure at a given institution.