MR features of tuberculous arachnoiditis.

Although tuberculosis is an uncommon cause of spinal arachnoiditis, it needs to be differentiated from other causes of arachnoiditis because it is a treatable disease. Myelography, which is the imaging modality of choice for the chronic adhesive stage of tuberculous arachnoiditis, usually reveals irregularity of the thecal sac, nodularity and thickening of nerve roots, clumping of roots to each other or to the thecal sac, or CSF block. Recently Gd-diethylenetriamine pentaacetic acid enhanced MRI has been found to be useful for the active phase of tuberculous infection, effectively demonstrating abnormally thickened and enhancing meninges, intra- and extramedullary tuberculous nodules, and spinal cord changes. We present the MRI features in a case of acute tuberculous arachnoiditis.