For lumbar, thoracic, cervical, and total columnar myelography to determine the presence of abnormalities in the spinal column, spinal canal, and central nervous system (CNS) as well as for cisternography by direct injection using standard radiologic techniques to visualize the basal cistern of the brain. For computerized tomography (CT) of the intracranial subarachnoid spaces and for ventriculography by direct injection using standard radiologic techniques to visualize the cerebral ventricles. Also used in pediatric angiocardiography to visualize lesions or malformations of the heart and obstructions or anomalies of the major thoracic vessels. Also used in adult peripheral arteriography to visualize specific regions of the vascular system and blood flow in such areas to help in the diagnosis and evaluation of neoplasms (known or suspected) or vascular diseases (congenital or acquired) that may cause changes in normal vascular anatomy or physiology. Metrizamide is also indicated in adults for intravenous digital arteriography of head and neck.