Comparison of the deformations of brain tissues caused by tumor in seizure and non-seizure patients

It is unclear why some patients with brain tumors present with seizures while others do not. As deformations of the brain due to the tumor growth are suspected to be in part responsible for seizures, we decided to compare the differences between the brain deformations in patients presenting with seizures versus those who did not. We modeled the brain deformations by estimating the non-linear transformation which registers the postoperative image - assumed to represent the normal brain - to the preoperative image - representing the brain deformed by the tumor - on a dataset of 19 brain tumor patients. We then estimated the determinant of the Jacobian of the corresponding deformation field and built histograms of the distribution of the deformations for each image. Statistical tests performed on the histograms of seizure and nonseizure patients led to some significant differences suggesting that a higher ratio of tissue compression could be the cause of seizures.