MR-IMAGING OF TUBERCULAR SPINAL ARACHNOIDITIS

OBJECTIVE. The purpose of our study was to examine the spectrum of abn ormalities seen on MR imaging in patients with tubercular spinal arach noiditis. MATERIALS AND METHODS. A retrospective analysis of MR findin gs in 22 cases of tubercular spinal arachnoiditis was carried out. The diagnosis had been established on the basis of clinical features, evi dence of associated tubercular meningitis or of tubercular spondylitis , and CSF analysis. RESULTS. Nineteen (86%) patients had involvement o f more than one spinal region, with the dorsal region being most commo nly involved. CSF showed increased signal intensity on T1-weighted ima ges in 17 (77%) patients, leading to complete loss of cord-CSF interfa ce in seven patients and shaggy cord outline in 10 patients. As sugges ted by increased signal intensity on T2-weighted images, we saw cord i nvolvement 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 of caud a equina nerve roots in six patients. Contrast-enhanced studies were a vailable in 20 patients. Meningeal enhancement was seen in 16 (80%) of 20 patients, and nerve root enhancement was seen in six (30%) patient s. 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. CONCLUS ION, MR imaging revealed several pathologic changes that occur in pati ents with tubercular spinal arachnoiditis and, hence, may play an impo rtant role in the diagnosis of this entity.