To the Editor.
—The two recent articles on CNS involvement in systemic cysticercosis (Archives 1982;39:534-539, 540-544) were important in increasing neurologists' awareness of an important health problem in parts of North America. Such infections are occasionally diagnosed even in Canada, not only in Latin American immigrants but also in the native population.McCormick et al (Archives 1982;39:534-539) described computed tomographic (CT) findings in this disease in adults that included parenchymal calcifications and contrastenhancing annular lesions denoting cysticercal cysts. In another recent study of cerebral cysticercosis in 89 Mexican children, López-Hernández and Garaizar1 demonstrated similar images and further defined the temporal sequence of CT changes in the natural course of the disease. Cerebral edema precedes the appearance of contrast-enhancing lesions, which then "disappear" as the surrounding edema subsides, only to reappear later as new cysts form and focal edema redevelops or as intracranial hypertension remits and relapses. Cystic lesions