Measurement of magnetization transfer in different stages of neurocysticercosis

The purpose of this study was to establish magnetization transfer ratio (MTR) in different stages of neurocysticercosis. A total 2,532 cysticerci were studied prospectively in 15 cases. MTR from different regions of the lesions (ie, the cyst, the protoscolex or mural nodule, the granuloma wall) were calculated in different stages of evolution/degeneration in all cases. Of a total 2,532 lesions studied, 2,261 (89.29%) were seen on routine spin-echo (SE) imaging. The rest of the lesions were only seen on magnetization transfer (MT) SE imaging. Maximum MTR was calculated from healing lesions (mean + SD = 31.0+/-2.8) and from the core of SE invisible lesions (30.0+/-5.1). Innocuous cystic lesions, which were hyperintense on T2-weighted images, did not show any MT (MTR = 5.10+/-1.2), whereas degenerating T2 hyperintense lesions showed MTR of 26.40+/-2.7. Nondegenerating and degenerating scolices showed an intermediate MTR of 21.7+/-3.3 and 15.0+/-4.5, respectively. MT varies between different parts of the lesion and also from the same part in different stages of evolution/degeneration of the lesion. The visibility of a lesion on MT-SE sequence was dependent on its MTR and its location at a particular site (cortical gray matter, white matter, or deep gray matter). The difference in MTR of the lesion and the surrounding brain parenchyma decides the resulting contrast and visibility of the lesion.