Acute Diffusion Tensor and Kurtosis Imaging and Outcome following Mild Traumatic Brain Injury

Abstract

In this prospective cohort study, we investigated associations between acute diffusion tensor and kurtosis imaging (DTI; DKI) metrics and persistent postconcussion symptoms (PPCS) 3 months after mild traumatic brain injury (MTBI). Adult patients with MTBI (n=176) and community controls (n=78) underwent 3 Tesla MRI within 72 hours postinjury, estimation of cognitive reserve at 2 weeks, and PPCS assessment at 3 months. Eight DTI and DKI metrics were examined with Tract-Based Spatial Statistics. Analyses were performed in the total sample, in uncomplicated MTBI only (i.e., without lesions on clinical MRI), and with cognitive reserve both controlled for and not. Patients with PPCS (n=35) had lower fractional anisotropy (in 2.7% of all voxels) and kurtosis fractional anisotropy (in 6.9% of all voxels), and higher radial diffusivity (in 0.3% of all voxels), than patients without PPCS (n=141). In uncomplicated MTBI, only fractional anisotropy was significantly lower in patients with PPCS. Compared to controls, patients with PPCS had widespread deviations in all diffusion metrics. When including cognitive reserve as a covariate, no significant differences in diffusion metrics between patients with and without PPCS were present, but patients with PPCS still had significantly higher mean, radial, and axial diffusivity than controls. In conclusion, patients who developed PPCS had poorer white matter microstructural integrity acutely after the injury, compared to patients who recovered, and healthy controls. Differences became less pronounced when cognitive reserve was controlled for, suggesting that preexisting individual differences in axonal integrity accounted for some of the observed differences.

White Matter Abnormalities and Cognitive Deficit After Mild Traumatic Brain Injury: Comparing DTI, DKI, and NODDI

“…The result of increased FA, MD, and rather an unchanged RD was supported by Veeramuthu et al ( 46 ) indicate that the supporting cells like astrocytes migrate to the site of injury, and caused the increase of cells density and diffusivity. Fourth, decreased MK was reported in a few studies on mTBI patients, and it was probably associated with degenerative changes and neuronal shrinkage ( 12 , 14 , 20 , 54 – 57 ). Furthermore, decreased ODI indicated that WM fibers tended to be parallel, which is consistent with the FA results in our study.…”

Advanced Neuroimaging Role in Traumatic Brain Injury: A Narrative Review

“…After mild TBI, a part of patients experienced persistent post-concussion symptoms (PPCS) for several months to years ( Polinder et al, 2018 ). Compared to the patients who recovered and healthy controls, mild TBI patients who developed PPCS showed more severely damaged white matter microstructural integrity after brain injury ( Stenberg et al, 2021 ). In severe TBI, high FA at the initial scan could predict favorable GOS outcome of 1 year, and increased FA in the internal capsule and in centrum semiovale during follow-up of 1 year, particularly in patients with favorable GOS outcome ( Sidaros et al, 2008 ).…”

Neuropathological Mechanisms of Mild Traumatic Brain Injury: A Perspective From Multimodal Magnetic Resonance Imaging

“…In the chronic phase after mTBI, most reports believe that FA values are reduced (Palacios et al, 2020;Oehr et al, 2021;Stenberg et al, 2021).…”