The role of contrast-enhanced MR imaging in the diagnosis of neurocysticercosis.

Pre- and postcontrast MR images of 17 patients with the diagnosis of neurocysticercosis were reviewed to evaluate the role of gadopentetate dimeglumine in MR imaging of this disease. The MR images, which were obtained on either a 0.5-T or 2.0-T superconducting system, revealed a total of 92 cysticerci in 17 patients. On contrast-enhanced T1-weighted images, 23 parenchymal cysticerci showed contrast enhancement. Ring-shaped enhancement was seen in only 6% (3/54) of cysticerci with intensity paralleling the CSF, while it was noted in 67% (16/24) of the cysticerci with intensity higher than CSF. Nodular enhancement was seen in granulomatous lesions with surrounding edema (29%, 4/14). Of 18 cysticerci with surrounding edema, 17 showed contrast enhancement. Basal meningeal enhancement, indicating meningitis, was observed in three patients. The results indicate that contrast enhancement usually occurs in patients in whom precontrast MR findings have shown active inflammatory reaction in the degenerating stage of the worm. Thus, postcontrast imaging is useful in a limited number of patients with neurocysticercosis; it should be used selectively in those whose clinical or precontrast MR studies show meningitis, granulomatous lesions, or cysts with surrounding edema.