Intrathecal Metrizamide Diagnosis of Downbeat Malformation Computed Tomography: Nystagmus in Arnold-Chiari I

Conventional computed tomographic scans are often inadequate for the evaluation of the medullary cervical junction and adjacent cerebellar structures. Visualization ofthe subarach- noid spaces from the distal tip ofthe dural spinal canal to the cranial cavity is greatly enhanced by the intrathecal injection of metrizamide. Photographs demonstrate findinTs with and without metrizamide injection in the case of a 58-year-old patient with Arnold-Chiari I malformation. (Surv Ophthalmol 27:123-125, 1982)