Arachnoiditis ossificans. Diagnosis with helical computed tomography.

Arachnoiditis ossificans (AO) is a rare entity in which ossification of the leptomeninges occurs. This report illustrates a patient with AO of the cervical and dorsal spine, diagnosed by helical computed tomography with multiplanar reconstruction. It demonstrates the value of computed tomography in diagnosing calcified plaques and the utility of multiplanar reconstruction in giving an exact anatomic reference to neurosurgeon.