Computed tomography (CT) in parenchymatous cerebral cysticercosis.

Cysticercosis is an infection with a larval or a bladder-worm stage of the species of Taenia. Cysticerci have a predeliction for the nervous system where they may be found in the meninges, the ventricles and within the brain itself. Brain involvement or parenchymatous form has an acute and chronic phase. Before the advent of CT scanning radiology was of little value in the acute parenchymatous cysticercosis, but with CT the changes within the brain can be recognised. In reviewing 14 cases of acute parenchymatous cysticercosis three CT patterns were found. 1. A diffuse low density pattern with no or little change after contrast medium 2. Multiple low densities with small rounded central areas of enhancement. 3. Large cystic lesions which may become ring lesions after contrast medium. We conclude that in an endemic area for cysticercosis, when one of these CT patterns is present, cysticercosis should be considered in the differential diagnosis. In a child where the clinical features are suggestive, the CT pattern may be diagnostic of cysticercosis. In the chronic parenchymatous stage the cysts have calcified and this may occur within one year of the acute onset. In 11 cases of chronic parenchymatous cysticercosis where the calcification was visible on the plain skull radiographs the CT scan added very little additional information. It may however be of value in confirming intracranial calcifications where their presence on the plain skull radiograph is in doubt.