Diffusion Tensor Imaging Profiles Can Distinguish Diffusivity and Neural Properties of White Matter Injury in Hydrocephalus vs. Non-hydrocephalus Using a Strategy of a Periodic Table of DTI Elements

Abstract

Background:The aim of this study was to create a simplistic taxonomy to improve transparency and consistency in, and reduce complexity of, interpreting diffusion tensor imaging (DTI) profiles in white matter disruption. Using a novel strategy of a periodic table of DTI elements, we examined if DTI profiles could demonstrate neural properties of disruption sufficient to characterize white matter changes specific for hydrocephalus vs. non-hydrocephalus, and to distinguish between cohorts of neural injury by their differing potential for reversibility.MethodsDTI datasets from three clinical cohorts representing pathological milestones from reversible to irreversible brain injury were compared to those of healthy controls at baseline, over time and with interventions. The final dataset comprised patients vs. controls in the following groupings: mild traumatic brain injury (mTBI), n = 24 vs. 27, normal pressure hydrocephalus (NPH), n = 16 vs. 9 and Alzheimer's disease (AD), n = 27 vs. 47. We generated DTI profiles from fractional anisotropy (FA) and mean, axial and radial diffusivity measures (MD, L1 and L2 and 3 respectively), and constructed an algorithm to map changes consistently to a periodic table of elements, which fully described their diffusivity and neural properties.ResultsMapping tissue signatures to a periodic table of DTI elements rapidly characterized cohorts by their differing patterns of injury. At baseline, patients with mTBI displayed the most preserved tracts. In NPH, the magnitude of changes was dependent on “familial” DTI neuroanatomy, i.e., potential for neural distortion from risk of ventriculomegaly. With time, patients with Alzheimer's disease were significantly different to controls across multiple measures. By contrast, patients with mTBI showed both loss of integrity and pathophysiological processes of neural repair. In NPH, some patterns of injury, such as “stretch/compression” and “compression” were more reversible following intervention than others; these neural profile properties suggested “microstructural resilience” to injury.ConclusionUsing the novel strategy of a periodic table of DTI elements, our study has demonstrated it is possible to distinguish between different cohorts along the spectrum of brain injury by describing neural profile properties of white matter disruption. Further work to contribute datasets of disease toward this proposed taxonomic framework would enhance the translatability of DTI profiles to the clinical-research interface.

Structural volumetric and Periodic Table DTI patterns in Complex Normal Pressure Hydrocephalus—Toward the principles of a translational taxonomy

“…Toward this novel language of interpretation, we organized DTI profiles reported by our group and others into a common taxonomic framework which described white matter tracts by their diffusivity and neural properties. We then confirmed its relevance to cohorts of Classic NPH ( Cl NPH) vs. comparator cohorts of mild traumatic brain injury (TBI) and Alzheimer’s disease (AD) ( Keong et al, 2022 ).…”

“…In this study, we built upon our prior understanding of such testing by documenting the neuroanatomical and microstructural alterations in Co NPH. As their DTI interpretation as compared to local controls are known, we then used our findings to validate and expand upon the Periodic Table of DTI Elements ( Keong et al, 2022 ; reproduced here in Tables 6 , 7 ) by comparing them to a set of healthy volunteers from the ADNI open-access dataset. We term this concept “controls-in-common”; by using this strategy, we hope to increase the accessibility of the Periodic Table of DTI Elements to a wider group of community users.…”

“…Tables 3 – 5 for Differences between Patients vs. Controls (for Changes between Cohorts vs. Themselves, refer to Keong et al, 2022 ). b.…”

“…Our work on DTI profiles has been published elsewhere ( Keong et al, 2017 , 2022 ; Lock et al, 2019 ). In brief, DTI profiles are a methodology of describing concurrent changes occurring across different DTI measures and distilling such complexity into their predominant direction and magnitude of changes for consistency of interpretation.…”

Does deep cerebral venous engorgement contribute to non-hydrocephalic pineal cysts becoming symptomatic? Some missing links

“…Going forwards, more advanced MR diffusion tensor imaging (DTI) techniques will provide a more comprehensive understanding of water movement in structures around and distant from the pineal recess. 7 …”