Understanding epileptogenesis in calcified neurocysticercosis with perfusion MRI

Calcified cysticercus larva with perilesional abnormality is thought to be responsible for seizures in patients with neurocysticercosis (NCC). However, it is not well understood why some calcified cysts are associated with seizures even without perilesional abnormality.

The study group consists of 30 subjects from an ongoing survey for disease burden estimation of a swine farming community who had a single calcified lesion without any perilesional abnormality with or without presentation of seizures. Each group consisted of 15 patients with calcified cysts and was labeled as asymptomatic and symptomatic. We performed dynamic contrast-enhanced (DCE) MRI on all these subjects and determined serum matrix metalloproteinase-9 (MMP-9) levels and MMP-9 gene polymorphisms.

DCE-MRI-derived rate transfer constant (k(ep)) and serum MMP-9 levels showed significant differences between symptomatic and asymptomatic subjects. We observed an increase in the MMP-9 levels, k(ep), and the volume transfer coefficient (k(trans)) in these lesions. We also observed a significant increase in MMP-9 (R279Q) gene polymorphism in symptomatic subjects compared with asymptomatic and control subjects.

Perilesional inflammation, which varies from symptomatic to asymptomatic subjects, can be quantified using DCE-MRI in calcified cysticercosis and may help distinguish these 2 groups with similar imaging findings. The observed increase in k(ep) with serum MMP-9 levels suggests that the former may serve as a biomarker of MMP-9 levels in these subjects. The significant MMP-9 (R279Q) gene polymorphism in symptomatic subjects might explain the differences in the observed DCE-MRI indices between symptomatic and asymptomatic subjects.