Modified Linear Fascicle Evaluation (mLiFE) for Improving the Fiber Tractography of Stroke Patients using Diffusion MRI

Tractography based on DTI (Diffusion Tensor Imaging) data can noninvasively probe the white matter structure, thus helps the assessment of central nerve injury such as stroke. The Linear Fascicle Evaluation (LiFE) can compare tractography algorithms by evaluating the tractography results. However, considering the pathological changes of stroke patients, the result in lesion area is doubtful. A modified LiFE (mLiFE) algorithm is proposed in this paper to improve the evaluation accuracy of the tractography results in lesion areas. mLiFE assumes that the diffusion of voxels without fiber crossing is isotropic and computes the main diffusion eigenvalue for every voxel, instead of choosing a fixed value as in LiFE. Additionally, by applying mLiFE in the tractography method which uses the Sparse fascicle models (SFM), the modified SFM (mSFM) is also proposed in this paper. Experiments on the DTI data of stroke patients who received neural stem cell transplantation prove that the proposed mLiFE can evaluate tractography results in the lesion area. In addition, mSFM can reflect neural fiber recovery following surgery efficiently. The proposed mLiFE enables accurate evaluation and fiber estimation for stroke patients and could provide insights of neural fiber recovery for clinicians