Diffusion Magnetic Resonance Imaging in Diffuse Low-Grade Gliomas

Abstract

Diffusion MRI is the first non-invasive window on the organization of the human brain white matter. By linking the direction of diffusion of water molecules in the brain with the local orientation of white matter fibers, the technique has enabled in vivo exploration of the architecture of white matter pathways at the individual patient scale. Such a non-invasive brain mapping tool is of special interest in the management of diffuse low-grade gliomas (DLGG) which are invasive lesions that migrate along white matter fibers. In particular, diffusion MRI tractography techniques enable three-dimensional visualization of the spatial relationship of the tumor with white matter structures associated with sensorimotor, language, and visual function. White matter mapping could help neurosurgeons characterize tumor invasion and maximize the extent of resection while preserving fibers associated with critical function. However, the complexity of diffusion MRI data and the challenges inherent to the validation of the anatomical accuracy of tractography reconstruction remain barriers to the use of the technology as a standalone tool for neurosurgical decision-making. Multidisciplinary efforts that bring together neurosurgeons, neuroradiologists, neuroanatomists, and neuroimaging scientists are needed to lower this barrier so that the development and application of innovative diffusion MRI acquisition sequences and post-processing tools can become part of the brain mapping apparatus for the treatment and monitoring of DLGG. This chapter covers the basics of diffusion MRI analysis, and introduces the current performances and challenges of using the technique for the neurosurgical treatment of DLGG.