Diffusion MRI of Chronic Traumatic Brain Injury: A Systematic Review and Meta-analysis
Poster No:
173
Submission Type:
Abstract Submission
Authors:
Yining Chen1, Jessica Hoffmann2, Warda Syeda1, Remika Mito3, Bradford Moffat1
Institutions:
1Melbourne Brain Centre Imaging Unit, Department of Radiology, University of Melbourne, Melbourne, Victoria, 2Department of Psychological Sciences, University of Melbourne, Melbourne, Victoria, 3Department of Psychiatry, University of Melbourne, Melbourne, Victoria
First Author:
Yining Chen
Melbourne Brain Centre Imaging Unit, Department of Radiology, University of Melbourne
Melbourne, Victoria
Melbourne Brain Centre Imaging Unit, Department of Radiology, University of Melbourne
Melbourne, Victoria
Co-Author(s):
Warda Syeda, PhD
Melbourne Brain Centre Imaging Unit, Department of Radiology, University of Melbourne
Melbourne, Victoria
Melbourne Brain Centre Imaging Unit, Department of Radiology, University of Melbourne
Melbourne, Victoria
Bradford Moffat
Melbourne Brain Centre Imaging Unit, Department of Radiology, University of Melbourne
Melbourne, Victoria
Melbourne Brain Centre Imaging Unit, Department of Radiology, University of Melbourne
Melbourne, Victoria
Introduction:
Accumulating evidence on traumatic brain injury (TBI) reveals not only acute damage but also chronic changes, which are associated with long-term neurological consequences and an increased incidence of secondary diseases. These post-TBI conditions have been linked to white matter (WM) injury that can be quantified non-invasively using diffusion magnetic resonance imaging (dMRI). Previous dMRI studies suggest altered WM integrity in various brain regions following TBI, although the findings appear heterogeneous across studies. Therefore, this study aimed to systematically examine the differences in dMRI metrics, in particular fractional anisotropy (FA) and mean diffusivity (MD), between chronic TBI patients and controls. The hypothesis was that dMRI metrics are sensitive to chronic WM changes following TBI and are different between patients and controls.
Methods:
This review was conducted in accordance with the PRISMA guidelines (Page, McKenzie, et al., 2021; Page, Moher, et al., 2021). The following electronic databases were searched: MEDLINE, Embase, PsycINFO, and Scopus. Of the 6102 records identified and screened, 30 studies were included in the meta-analysis based on the inclusion criteria. All statistical analyses were performed with R (R version 4.4.2). A random-effects model was applied to address study heterogeneity. The Hedges' g effect sizes for FA and MD were computed for individual WM regions of interest (ROIs) in mild and moderate-to-severe TBI. Pearson's correlations were calculated between the effect sizes and co-variates, including clinical and technical factors.
Results:
Decreased FA and increased MD values were found in most WM ROIs (92% and 80%, respectively) in mild TBI. In moderate-to-severe TBI, all ROIs showed decreased FA and increased MD values, and the effect sizes became much larger compared to those observed in mild TBI. 8 out of 9 regions showed a large effect (∣g∣ ≥ 0.8). Significant FA reductions were observed in the body (g = -2.16, p < 0.001), genu (g = -1.78, p < 0.001) and splenium (g = -1.76, p < 0.001) of corpus callosum. The effect sizes of FA were found to correlate with the proportion of male participants in both mild (R = -0.32, p < 0.01) and moderate to severe (R = -0.33, p < 0.05) TBI.
Conclusions:
This systematic review provides compelling evidence that the biomarkers of chronic TBI, FA and MD, indicate persistent and widespread WM alterations across the brain following chronic TBI. These changes become more pronounced in moderate-to-severe cases, indicating a dose-dependency of dMRI metrics as biomarkers. The effect sizes for FA, however, remain small in mild TBI, suggesting the need for more advanced dMRI biomarkers to better detect axonal injury. Moreover, while the corpus callosum remains the most investigated region, there are other WM ROIs that also showed evidence of altered WM integrity and need to be studied more.
Disorders of the Nervous System:
Neurodegenerative/ Late Life (eg. Parkinson’s, Alzheimer’s) 1
Modeling and Analysis Methods:
Diffusion MRI Modeling and Analysis 2
Other Methods
Keywords:
Meta- Analysis
MRI
White Matter
WHITE MATTER IMAGING - DTI, HARDI, DSI, ETC
Other - Chronic Traumatic Brain Injury (TBI)
1|2Indicates the priority used for review
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2. Page, M. J., Moher, D., et al. (2021). PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews. British Medical Journal, 372, n160.