Exploring Peritumoral Neural Tracts by Using Neurite Orientation Dispersion and Density Imaging.

Shin Tai Chong,Ching-Po Lin,Yi-Chia Kung,Chien-Yuan Eddy Lin,Chih-Chin Heather Hsu,Hung-Wen Kao,Gang Zhao,Xinrui Liu,Chun-Yi Zac Lo,Yunqian Li,Chu-Chung Huang,Kuan-Tsen Kuo

doi:10.3389/fnins.2021.702353

Abstract

Diffusion Tensor Imaging (DTI) tractography has been widely used in brain tumor surgery to ensure thorough resection and minimize functional damage. However, due to enhanced anisotropic uncertainty in the area with peritumoral edema, diffusion tractography is generally not practicable leading to high false-negative results in neural tracking. In this study, we evaluated the usefulness of the neurite orientation dispersion and density imaging (NODDI) derived tractography for investigating structural heterogeneity of the brain in patients with brain tumor. A total of 24 patients with brain tumors, characterized by peritumoral edema, and 10 healthy counterparts were recruited from 2014 to 2021. All participants underwent magnetic resonance imaging. Moreover, we used the images obtained from the healthy participants for calibrating the orientation dispersion threshold for NODDI-derived corticospinal tract (CST) reconstruction. Compared to DTI, NODDI-derived tractography has a great potential to improve the reconstruction of fiber tracking through regions of vasogenic edema. The regions with edematous CST in NODDI-derived tractography demonstrated a significant decrease in the intracellular volume fraction (VFic, p < 0.000) and an increase in the isotropic volume fraction (VFiso, p < 0.014). Notably, the percentage of the involved volume of the concealed CST and lesion-to-tract distance could reflect the motor function of the patients. After the tumor resection, four patients with 1–5 years follow-up were showed subsidence of the vasogenic edema and normal CST on DTI tractography. NODDI-derived tractography revealed tracts within the edematous area and could assist neurosurgeons to locate the neural tracts that are otherwise not visualized by conventional DTI tractography.

Highlights

The cerebral neoplasm may increase the intracranial pressure and cause neural tract deviation, infiltration, or destruction in the site of tumor growth and peritumoral areas (Assaf and Pasternak, 2008)
We evaluated the first eigenvector for the principal directions on Diffusion Tensor Imaging (DTI) tractography and used fractional anisotropy (FA) as the fiber tractography termination criteria
receiver operating characteristic (ROC) Diagnostic Performance Analysis In ROC diagnostic performance analysis, we found that lesion-totract distance (LTD), D-only volume, D-only percentage of involved volume (PIV), N-only volume, N-only volume-LTD (N-only volume with weighted LTD), N-only PIV, and N-only PIV-LTDs (N-only PIV with weighted LTD) had significant differences between patients with and without surgery-related paresis

Summary

Introduction

The cerebral neoplasm may increase the intracranial pressure and cause neural tract deviation, infiltration, or destruction in the site of tumor growth and peritumoral areas (Assaf and Pasternak, 2008). Various magnetic resonance imaging (MRI) techniques are used to access and localize brain tumors to obtain a thorough resection and minimize functional loss. Among these techniques, diffusion tensor imaging (DTI) has been widely used to demonstrate the structural contents and peritumoral neural tracts. As a simplified model, DTIderived tractography faces a substantial challenge in resolving the fiber tract within a voxel that comprises heterogeneous compartments including infiltrating cells and edematous tissues (Lecoeur et al, 2014; Chen et al, 2016; Gong et al, 2018; Ye et al, 2020)

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