Fusion of white and gray matter geometry: A framework for investigating brain development

Abstract

Current neuroimaging investigation of the white matter typically focuses on measurements derived from diffusion tensor imaging, such as fractional anisotropy (FA). In contrast, imaging studies of the gray matter oftentimes focus on morphological features such as cortical thickness, folding and surface curvature. As a result, it is not clear how to combine findings from these two types of approaches in order to obtain a consistent picture of morphological changes in both gray and white matter. In this paper, we propose a joint investigation of gray and white matter morphology by combining geometrical information from white and the gray matter. To achieve this, we first introduce a novel method for computing multi-scale white matter tract geometry. Its formulation is based on the differential geometry of curve sets and is easily incorporated into a continuous scale-space framework. We then incorporate this method into a novel framework for “fusing” white and gray matter geometrical information. Given a set of fiber tracts originating in a particular cortical region, the key idea is to compute two scalar fields that represent geometrical characteristics of the white matter and of the surface of the cortical region. A quantitative marker is created by combining the distributions of these scalar values using Mutual Information. This marker can be then used in the study of normal and pathological brain structure and development. We apply this framework to a study on autism spectrum disorder in children. Our preliminary results support the view that autism may be characterized by early brain overgrowth, followed by reduced or arrested growth [7].

Combined Diffusion Tensor Imaging and Quantitative Susceptibility Mapping Discern Discrete Facets of White Matter Pathology Post-injury in the Rodent Brain

“…Extended on this, based on previous literature and our results, we have summarized the dynamics of the expected microstructural changes triggered following a TBI in the white matter (Figure 6). We suggest that controlled cortical impact affects the physiological and biomechanical properties of gray and white matter that can be detected using non-invasive imaging tools (80,81). In the step (i) and (ii) of Figure 6, we demonstrated that the axons that were normal before injury appear to be swollen within 5 h post-injury that has stretched the myelin sheath reflected by increase the radial diffusivity (perpendicular) without any change in the axial (parallel) diffusivity (82) (Figure 1).…”

AxTract: Toward microstructure informed tractography

“…Recent results have shown that, albeit tractography can extract large white matter fascicles from DW‐MRI, there is a high incidence of erroneous streamlines (false positives) resulting from current tractography algorithms [Côté et al, ; Jbabdi et al, ; Jones, ; Maier‐Hein et al, ; Thomas et al, ]. This is largely due to complex ambiguous local fiber configurations (e.g., crossing, kissing, or fanning) [Maier‐Hein et al, ; Savadjiev et al, ]. Furthermore, the relationship between the resulting streamlines and the underlying white matter microstructure characteristics, such as axon diameter, remains poorly understood [Jones, ].…”

Subject-specific abnormal region detection in traumatic brain injury using sparse model selection on high dimensional diffusion data

“…We have made the choice of connecting neighboring GM and WM regions with an edge as there is increasing evidence that the tissue and geometric properties of proximal GM/WM regions are stongly related Miyata et al (2009); Koch et al (2013); Liu et al (2014); Savadjiev et al (2014). Furthermore, the graph is only a guide for the precision matrix estimation process.…”