Which imaging studies are indicated in the workup of neurocysticercosis (tapeworm infestation)?

Updated: Apr 15, 2021
  • Author: Lisandro Irizarry, MD, MBA, MPH, FACEP; Chief Editor: Jeter (Jay) Pritchard Taylor, III, MD  more...
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Answer

Imaging studies are not only useful in differential diagnosis and evaluation of neurocysticercosis, but they are important in identifying the number, the location, and the stage of the infestation.

The size of cysticerci varies according to location in the CNS. If located in the brain parenchyma, cysts are rarely larger than 10 mm in diameter because of physical space limitations. In contrast, cysts located in the cisterns of the cerebrospinal fluid may grow to 5 cm or greater in diameter.

Appearance of the cysticerci depends on the stage of development. On entering the CNS, the cysticerci are in a vesicular stage where the parasites are viable and surrounding tissue inflammatory changes are scant. After a variable time (maybe years), the host attacks immunologically and the process of degeneration occurs; this process changes the appearance of the cysticerci until ultimately complete degeneration leaves a nodular calcified cyst.

Generally, MRI is better than CT for the diagnosis of neurocysticercosis, detecting up to 60% of cases missed on CT. However, MRI is less sensitive than CT in identifying small calcifications, and many patients have parenchymal calcifications as the sole evidence of the disease (up to 40% of symptomatic patients). This along with cost-effectiveness lends to CT as the image study of choice and MRI for more inconclusive findings. Also see Cysticercosis and Cysticercosis, CNS.

Ultrasonography may be useful in evaluation of patients with orbital infestations.


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