New lesions were shown by Tc99m bone scans to have developed in sixty patients with known metastatic
cancer or high-risk primary
cancer and normal neurologic examinations; they were further evaluated with plain radiographs, spinal computed tomography (CT), and CT myelography (CT-M) according to an algorithm. Three groups were identified based on plain radiographs: group 1 (normal radiograph), group 2 (
compression fracture as indicated by radiograph), group 3 (evidence of
metastasis as indicated by radiograph). In group 1 (n = 18), spinal CT revealed that 33% of the patients had benign disease and 67%,
metastases; epidural compression was seen in 25% of the patients with
metastasis as indicated by CT-M. In group 2 (n = 26), CT-M disclosed that 38% had a benign
compression fracture and 62% had
metastases and that 63% of the patients with
metastases had an epidural compression. In group 3 (n = 16), spinal CT revealed that 15 patients had
metastases (one patient had benign disease). Epidural cord compression was seen in 47% of the patients with metastatic disease. In all groups, the presence of cortical bone discontinuity around the neural canal (seen in 31 patients) was highly associated with epidural compression (seen in 20 patients). Our approach allowed the early and accurate diagnosis of spinal
metastasis and
epidural tumor as well as the diagnosis of benign disease and was useful in planning optimal local
therapy.