Myelography with metrizamide: effect of contrast removal on side effects.

Moderately severe side effects, such as prolonged headache, nausea, vomiting, or psychoneurologic symptoms, were noted in 27 (32%) of 84 patients in whom the contrast medium was not removed. Conversely, among 73 patients from whom 20-25 ml of cerebrospinal fluid with the contrast medium was removed, only 10 (14%) experienced adverse effects, a statistically significant reduction. Although new contrast agents, such as iohexol and iopamidol, are reportedly less toxic than metrizamide, the contrast-removal technique described here may be indicated when large amounts of any contrast medium are used.

Posttherapeutic cerebral radionecrosis: a complication of head and neck tumor therapy.

Patients with treated head and neck cancer may have focal neurologic symptoms and personality changes due to delayed cerebral radionecrosis. A history of past treatment should direct the physician to consider these lesions in the differential diagnosis. Craniotomy is the management recommended. Histopathologic changes include fibrotic response of the meninges with pleomorphic and vacuolated fibroblasts, capillary hyperplasia, reactive astrocytes, and fibrosis of the blood vessels. Amyloid is deposited in the arteriolar walls and extracellular space. Ischemic, autoimmune, or vascular mechanisms, and glial alterations have all been considered in the pathogensis of delayed cerebral radionecrosis. Some researchers have concluded that chemotherapeutic agents, such as methotrexate, may contribute to its production.