MR imaging of tubercular spinal arachnoiditis

The purpose of our study was to examine the spectrum of abnormalities seen on MR imaging in patients with tubercular spinal arachnoiditis. A retrospective analysis of MR findings in 22 cases of tubercular spinal arachnoiditis was carried out. The diagnosis had been established on the basis of clinical features, evidence of associated tubercular meningitis or of tubercular spondylitis, and CSF analysis. Nineteen (86%) patients had involvement of more than one spinal region, with the dorsal region being most commonly involved. CSF showed increased signal intensity on T1-weighted images in 17 (77%) patients, leading to complete loss of cord-CSF interface in seven patients and shaggy cord outline in 10 patients. As suggested by increased signal intensity on T2-weighted images, we saw cord involvement in 18 (82%) patients. Three of these patients had evidence of cord cavitation. Other findings seen on unenhanced images were CSF loculations in five patients, nodules in subarachnoid space in six patients, and clumping of cauda equina nerve roots in six patients. Contrast-enhanced studies were available in 20 patients. Meningeal enhancement was seen in 16 (80%) of 20 patients, and nerve root enhancement was seen in six (30%) patients. Cord enhancement was seen in four (20%) of 20 patients. Enhancement was observed along the surface of the cord in two of these patients, whereas the other two patients showed central enhancement. Associated findings were tubercular spondylitis in two patients, basal exudate in eight patients, and intracranial granulomas in five patients. MR imaging revealed several pathologic changes that occur in patients with tubercular spinal arachnoiditis and, hence, may play an important role in the diagnosis of this entity.