Unusual Extensive T1 Hyperintense Signals on MR Imaging in Neurocysticercosis

Abstract

Neurocysticercosis (NCC) is a common cause of morbidity in many developing countries and a common cause of seizure disorder in children and adults. The 4 stages of NCC are vesicular, vesicular colloidal, granular nodular, and nodular calcified.1 The appearance on MR imaging would depend on the stage of the disease. Most commonly, NCC presents as isohypointense lesions on T1-weighted MR imaging. To our knowledge, extensive hyperintense signals on T1-weighted images have not been described for NCC. A young man 22 years of age presented with headache on and off for 5-6 months. There was no history of seizures, which was also very unusual in his case. Plain and contrast MR imaging of the brain was performed. T1-weighted images revealed multiple hyperintense foci of varying sizes, in bilateral cerebral, cerebellar hemispheres and the brain stem (Fig 1). The T1 hyperintense signals were thicker in the right cerebellar hemisphere (Fig 2). Multiple other lesions were revealed on gradient images, which were not demonstrated on routine MR images. These multiple extensive T1 hyperintense signals were confirmed to be calcifications on CT, which was performed subsequent to the MR imaging. Few of the T1 hyperintense lesions showed mild enhancement on contrast administration.The MR imaging appearance and contrast characteristics would depend on the stage of the parasitic cyst. The unusual appearance of such extensive T1 hyperintense signals, as seen in our patient, has not been described earlier and is probably due to calcifications, which are known to appear hyperintense on T1-weighted MR imaging.

Atypical T1 Hyperintense Neurocysticercosis Masquerading As Cystic Brain Metastases

“…The cause of T1-weighted hyperintensity in NCC has not been well described in the literature. Small eccentric T1-weighted hyperintense areas may occur as a result of the paramagnetic effect of the soft calcification in the scolex of the larva, which on gradient recalled echo/SWI appears as a hypointense signal and corresponds to hyperdense calcified areas on CT. 6 The hyperintensity of the cystic fluid component of the lesion can be secondary to degeneration of the encysted larval form. The cyst fluid becomes turbid with an increased amount of proteinaceous material, which explains the hyperintense signal on T1-weighted sequence and can be considered an early sign of degeneration of cysticercus larva and its transformation into the colloidal vesicular stage.…”