Brain Stiffness Correlates With Pathological Tissue in Patients With Drug-Resistant Epilepsy Due to Rasmussen Encephalitis and Focal Cortical Dysplasia.

BACKGROUND AND

OBJECTIVES

Complete resection of epileptogenic zone is the single most important determinant of favorable seizure outcomes in resective surgery. However, identifying and resecting this zone is challenging in patients harboring diffuse; MRI-occult malformations of cortical development, such as focal cortical dysplasia; or acquired pathology, such as Rasmussen encephalitis. Intraoperative adjuncts that can aid in identifying the lesion and/or epileptogenic zone can optimize the extent of resection and seizure outcome. We sought to study a novel intraoperative tool, brain tonometer, to measure brain stiffness and correlate with histopathological and radiological findings.

METHODS

Brain stiffness was measured at various presumed normal and abnormal areas of the cortex during surgery in 2 patients with drug-resistant epilepsy. These results were correlated with preoperative and intraoperative neuroimaging and histopathology.

RESULTS

We found brain stiffness correlated well with the degree of inflammation and cortical disorganization.

CONCLUSION

Brain tonometry may help to intraoperatively identify inflammatory brain tissue along with structural and histopathological abnormalities. In select cases, this could potentially allow more tailored resections of the underlying lesion, to ensure complete removal of the epileptogenic lesion and improve the probability of achieving seizure freedom, while sparing normal brain leading to better functional outcomes.