Communicating spinal arachnoid cysts: diagnosis by delayed metrizamide computed tomography

A case of an extradural spinal arachnoid cyst is presented with emphasis on the neuroradiologic characteristics of this lesion. The cyst was definitely diagnosed by delayed metrizamide spinal computed tomography. Extradural spinal arachnoid cysts, or diverticula, have been the subject of much discussion in the neuroradiologic and neurosurgical literature. However, the appearance of a communicating arachnoid cyst on delayed spinal computed tomography after metrizamide myelography is heretofore undescribed in the English language neurosurgical literature.