Tuberculous arachnoiditis of the spine: findings on myelography, CT, and MR imaging.

Tuberculosis (TB) is a rare cause of spinal arachnoiditis. It may occur primarily or secondary to intracranial or vertebral infection; unlike other types of arachnoiditis, it frequently involves the spinal cord as well as the meninges and the nerve roots. We retrospectively reviewed 13 conventional myelograms, eight CT myelograms, and five Gd-DTPA-enhanced MR images in 13 patients with spinal TB radiculomyelitis (arachnoiditis). Eleven patients had intracranial TB meningitis at the time of diagnosis or before. Ten patients were less than 30 years old. Conventional myelographic findings included a block of the CSF (11/13), most commonly at the level of the conus medullaris; irregular or indistinct thecal sac contour (9/13); multiple fine and/or coarse nodular defects (8/13); nerve-root thickening (7/13); and vertical bandlike adhesive defects (4/13). CT myelography showed intradural nodular masses suggesting tuberculomas at or just above the level of the block (4/8), irregularity of the spinal cord surface (4/8), irregular filling or obliteration of subarachnoidal space (6/8), and root thickening (5/8). Gd-DTPA-enhanced MR images revealed enhancing nodules suggesting tuberculomas (2/5); enhancement of the dura-arachnoid complex around the cord (3/5); and segmental enhancement of the thoracic cord, suggesting either infarction caused by vasculitis or TB myelitis in association with diffuse cord swelling (1/5). Plain MR findings were much less conspicuous, showing only an indistinct or irregular dura-arachnoid-cord complex (4/5). In conclusion, the conventional myelographic findings are considered to be virtually diagnostic of spinal TB radiculomyelitis in young patients with antecedent or coexisting TB meningitis.(ABSTRACT TRUNCATED AT 250 WORDS)