Spinal computed tomography scanning in the evaluation of metastatic disease.

Twenty patients with known metastatic cancer or high-risk primary cancer developed new lesions on Tc 99m bone scans and had normal plain radiographs. Spinal computed tomography (CT) was performed on all new bone-scan-positive lesions in minimal examination time. Fifteen patients had extensive metastatic vertebral disease and received local radiotherapy. One patient with new metastatic vertebral disease on CT was treated only with chemotherapy and developed acute spinal cord compression. Four patients had discogenic disease or degenerative disease but no evidence of metastases. Radionuclide bone scans are more sensitive but less specific than plain radiographs in detecting early bone metastases. Early and accurate diagnosis of metastasis is particularly important in the axial spine to prevent epidural compression and fracture. Spinal CT is valuable for identifying the presence and extent of vertebral metastases, as well as the presence of benign disease in cancer patients.