Diffusion Tensor Imaging Findings in Post-Concussion Syndrome Patients after Mild Traumatic Brain Injury: A Systematic Review

Abstract

ObjectivesTo review the evidence for the use of diffusion tensor imaging (DTI) parameters in the human brain as a diagnostic tool for and predictor of post-concussion syndrome (PCS) after a mild traumatic brain injury (mTBI).DesignSystematic review.Data sourcesAll relevant studies in AMED, Embase, MEDLINE, Ovid, PubMed, Scopus, and Web of Science through 20 May, 2016.Study selectionStudies that analyze traditional DTI measures [fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD)] and the severity of PCS symptoms or the development of PCS in humans after an mTBI.Data extractionPopulation studied, patient source, mTBI diagnosis method, PCS diagnosis method, DTI values measured, significant findings, and correlation between DTI findings and PCS.Data synthesisTen studies investigated correlations between DTI values and PCS symptom severity or between DTI values and the development of PCS in mTBI patients. Decreased FA and increased MD and RD were associated with the development and severity of PCS. AD was not found to change significantly. Brain regions found to have significant changes in DTI parameters varied from study to study, although the corpus callosum was most frequently cited as having abnormal DTI parameters in PCS patients.ConclusionDTI abnormalities correlate with PCS incidence and symptom severity, as well as indicate an increased risk of developing PCS after mTBI. Abnormal DTI findings should prompt investigation of the syndrome to ensure optimal symptom management at the earliest stages. Currently, there is no consensus in the literature about the use of one DTI parameter in a specific region of the brain as a biomarker for PCS because no definite trends for DTI parameters in PCS subjects have been identified. Further research is required to establish a standard biomarker for PCS.

Brain Connectivity and Behaviour in Post-Concussion Syndrome: A Scoping Review Protocol

“…There have been few reviews summarizing existing literature on structural and functional changes along with behavioural outcomes, including cognitive impairments, neuropsychiatric de cits or symptomology, in patients with persisting post-concussive symptoms. Khong et al 25 , reported that loss of integrity in long white matter tracts such as corpus callosum was the most cited abnormality in PCS literature, which was consistent with a previous review. 17 The current literature in PCS is limited because of a lack of converging knowledge due to few studies published on the topic.…”

“…17 The current literature in PCS is limited because of a lack of converging knowledge due to few studies published on the topic. 25 As described, most of the knowledge synthesis in the eld has focused on only one domain: loss of white matter integrity, disruption of functional connectivity or symptoms/behavioural de cits observed in patients with PCS. To our knowledge, there is no systematic summary of literature focused on understanding the structural or functional changes along with cognitive, neuropsychiatric measures or symptom severity in the adult population with PCS.…”

Management of Concussion and Mild Traumatic Brain Injury: A Synthesis of Practice Guidelines

“…[36][37][38] Magnetic resonance imaging studies using modern techniques such as diffusion tensor imaging suggest that microstructural pathology (eg, weakened integrity of long white matter tracts) can also be a feature of mTBI, 39 although the nature, location, time course, and clinical significance of such changes are unclear. [40][41][42] Clinical presentation and diagnosis mTBI can be challenging to diagnose in any setting because the acute signs and symptoms of altered mental status (AMS) are often subtle and transient, and available diagnostic tests (eg, CT) are not sensitive. These issues may be compounded in primary care, where patients are often first evaluated days or even weeks after an injury event and factors that mimic mTBI-like symptoms (fig 1) may have emerged.…”

Microstructure of the Corpus Callosum Long after Pediatric Concussion

“…Acutely following concussion, clinical or behavioral manifestations of white matter alterations may include worse post-concussion symptom severity and poorer cognitive performance (Geary, Kraus, Pliskin, & Little, 2010;Hellstrøm et al, 2017;Khong, Odenwald, Hashim, & Cusimano, 2016;Womack et al, 2017). A systematic review conducted by Khong and colleagues concluded that decreased FA and increased MD and RD are correlated with greater symptom severity and prolonged post-concussion symptoms (Khong et al, 2016).…”