Anisotropy of anomalous diffusion improves the accuracy of differentiating low- and high-grade cerebral gliomas

Magn Reson Imaging. 2018 Sep:51:14-19. doi: 10.1016/j.mri.2018.04.005. Epub 2018 Apr 17.

Abstract

Background: Anomalous diffusion model has been introduced and shown to be beneficial in clinical applications. However, only the directionally averaged values of anomalous diffusion parameters were investigated, and the anisotropy of anomalous diffusion remains unexplored. The aim of this study was to demonstrate the feasibility of using anisotropy of anomalous diffusion for differentiating low- and high-grade cerebral gliomas.

Methods: Diffusion MRI images were acquired from brain tumor patients and analyzed using the fractional motion (FM) model. Twenty-two patients with histopathologically confirmed gliomas were selected. An anisotropy metric for the FM-related parameters, including the Noah exponent (α) and the Hurst exponent (H), was introduced and their values were statistically compared between the low- and high-grade gliomas. Additionally, multivariate logistic regression analysis was performed to assess the combination of the anisotropy metric and the directionally averaged value for each parameter. The diagnostic performances for grading gliomas were evaluated using a receiver operating characteristic (ROC) analysis.

Results: The Hurst exponent H was more anisotropic in high-grade than in low-grade gliomas (P = 0.015), while no significant difference was observed for the anisotropy of α. The ROC analysis revealed that larger areas under the ROC curves were produced for the combination of α (1) and the combination of H (0.813) compared with the directionally averaged α (0.979) and H (0.594), indicating an improved performance for tumor differentiation.

Conclusion: The anisotropy of anomalous diffusion can provide distinctive information and benefit the differentiation of low- and high-grade gliomas. The utility of anisotropic anomalous diffusion may have an improved effect for investigating pathological changes in tissues.

Keywords: Anisotropy; Anomalous diffusion; Cerebral glioma; High b-value diffusion imaging; Tumor grading.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Anisotropy
  • Brain Neoplasms / diagnostic imaging*
  • Brain Neoplasms / pathology*
  • Diffusion Magnetic Resonance Imaging / methods*
  • Female
  • Glioma / diagnostic imaging*
  • Glioma / pathology*
  • Humans
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Neoplasm Grading