Problems in distinguishing spinal tuberculosis from neoplasia on MRI.

We reviewed MRI studies of 60 patients presenting with extradural compressive myeloradiculopathy secondary to vertebral disease to assess the imaging features which may help in differentiating tuberculous from neoplastic disease. Spin-echo T1-, proton density-and T2-weighted images were available for all patients and fast low-angle shot images with a low flip angle for 21 patients. Contrast-enhanced images were available for 28 patients. There were 41 patients with tuberculosis and 19 patients with neoplastic disease (metastases 11, lymphoma 6, plasmacytoma 1, and giant cell tumour 1). Discovertebral disease with or without involvement of the posterior arch was a feature not only of tuberculous spondylitis (30 patients) but also of metastases (6). The remaining 11 patients with tuberculosis had "atypical" involvement (vertebral body with or without posterior arch in 8 and posterior arch alone in 3) described as typical of neoplasms. This "typical" involvement was seen in metastases (5), lymphoma (6) and the 2 primary bone tumours. The presence of an abscess helped in differentiating tuberculosis from neoplasia in 22 of the 41 patients with tuberculosis and was absent in all with neoplasms. The presence of bone fragments in 16 patients (8 with and 8 without an abscess) was found to be specific for tuberculosis. In the absence of an abscess or bone fragments, image-guided biopsy is essential to establish the diagnosis.