Diffusion MR imaging acquisition and analytics for microstructural delineation in pre‐clinical models of TBI

Abstract

Significant progress has been made toward improving both the acquisition of clinical diffusion‐weighted imaging (DWI) data and its analysis in the uninjured brain, through various techniques including a large number of model‐based solutions that have been proposed to fit for multiple tissue compartments, and multiple fibers per voxel. While some of these techniques have been applied to clinical traumatic brain injury (TBI) research, the majority of these technological enhancements have yet to be fully implemented in the preclinical arena of TBI animal model‐based research. In this review, we describe the requirement for preclinical, MRI‐based efforts to provide systematic confirmation of the applicability of some of these models as indicators of tissue pathology within the injured brain. We review how current DWI techniques are currently being used in animal TBI models, and describe how both acquisition and analytic techniques could be extended to leverage the progress made in clinical work. Finally, we highlight remaining gaps in the preclinical pipeline from data acquisition to final analysis that currently have no real, preclinical‐based correlate.

Multi-Mechanistic Approaches to the Treatment of Traumatic Brain Injury: A Review

“…MRI has been studied in clinical trials, predominantly in mTBI in the subacute or chronic phase, as it is available in most academic medical centers and does not expose the patient to ionizing radiation [ 174 , 177 ]. MRI sequences, including diffusion weighted imaging (DWI), can be used to image cerebral edema following TBI, even in the first few days following injury [ 178 , 179 ], which could guide the early administration of therapies to reduce edema [ 14 ]. Other advanced MRI techniques, such as functional MRI (fMRI) and magnetic resonance spectroscopy (MRS), may have a role in guiding treatment decisions after TBI.…”

Multi-mechanistic Approaches to the Treatment of Traumatic Brain Injury: A Review

“…In moderate and severe TBI multimodal imaging historically plays a greater role in prognostication and determining the need and approprateness of aggressive interventions [138,139]. Multimodal MRI has been studied in clinical trials, predominantly in mTBI in the subacute or chronic phase, as it is available in most academic medical centers and does not expose the patient to ionizing radation [137,140] MRI sequences including diffusion weighted imaging (DWI) can be used to image cerebral edema following TBI, even in the first few days following injury [141,142], which could guide the early administration of therapies to reduce edema [12]. Other advanced MRI sequences such as functional MRI (fMRI) and magnetic resonance specroscopy (MRS) may have a role in guiding treatment decisions after TBI.…”

White and gray matter integrity evaluated by MRI-DTI can serve as noninvasive and reliable indicators of structural and functional alterations in chronic neurotrauma

“…Although Laitinen and colleagues 8 revealed persistent microstructural tissue changes in white matter tracts using mainly ex vivo DTI in a rat model of TBI, it still needs more preclinical in vivo data to ascertain whether white and gray matter integrity evaluated by MRI-DTI can serve as noninvasive and reliable indicators of structural and functional alternations in chronic neurotrauma. Since 1994, at least 145 publications have utilized DTI to detect TBI-related pathology 9 ; however, again needs to fill the gap relating behavioral outcomes with pathologic outcomes and also DTI outcomes in several brain regions in chronic TBI. Furthermore, clinical evidence shows repeated mild TBI increases morbidity risk and long-term neurodegenerative pathology such as chronic traumatic encephalopathy 10 , 11 .…”