Quantitative Susceptibility Mapping after Sports-Related Concussion

Koch, Kevin M.; Meier, Timothy B.; Karr, Robin; Nencka, Andrew S.; Muftuler, L. Tugan; McCrea, Michael

doi:10.3174/ajnr.a5692

Cited by 24 publications

(32 citation statements)

References 33 publications

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“…Yet there has been a lag in the acceptance of the method for the analysis of traumatic axonal injury. Recently, Koch et al reported increased QSM values in concussion patients in white and gray matter within 24 h post-injury that persisted up to 8 days and normalized after 6 months (44). Pathophysiological reasons for the changes were not provided.…”

Section: Introductionmentioning

confidence: 99%

Combined Diffusion Tensor Imaging and Quantitative Susceptibility Mapping Discern Discrete Facets of White Matter Pathology Post-injury in the Rodent Brain

Soni

Vegh

et al. 2020

Front. Neurol.

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Early loss of white matter microstructure integrity is a significant cause of long-term neurological disorders following traumatic brain injury (TBI). White matter abnormalities typically involve axonal loss and demyelination. In-vivo imaging tools to detect and differentiate such microstructural changes are not well-explored. This work utilizes the conjoint potential offered by advanced magnetic resonance imaging techniques, including quantitative susceptibility mapping (QSM) and diffusion tensor imaging (DTI), to discern the underlying white matter pathology at specific time points (5 h, 1, 3, 7, 14, and 30 days) post-injury in the controlled cortical impact mouse model. A total of 42 animals were randomized into six TBI groups (n = 6 per group) and one sham group (n = 6). Histopathology was performed to validate in-vivo findings by performing myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) immunostaining for the assessment of changes to myelin and astrocytes. After 5 h of injury radial diffusivity (RD) was increased in white matter without a significant change in axial diffusivity (AxD) and susceptibility values. After 1 day post-injury RD was decreased. AxD and susceptibility changes were seen after 3 days post-injury. Susceptibility increases in white matter were observed in both ipsilateral and contralateral regions and persisted for 30 days. In histology, an increase in GFAP immunoreactivity was observed after 3 days post-injury and remained high for 30 days in both ipsilateral and contralateral white matter regions. A loss in MBP signal was noted after 3 days post-injury that continued up to 30 days. In conclusion, these results demonstrate the complementary ability of DTI and QSM in discerning the micro-pathological processes triggered following TBI. While DTI revealed acute and focal white matter changes, QSM mirrored the temporal demyelination in the white matter tracts and diffuse regions at the chronic state.

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Section: Introductionmentioning

confidence: 99%

Combined Diffusion Tensor Imaging and Quantitative Susceptibility Mapping Discern Discrete Facets of White Matter Pathology Post-injury in the Rodent Brain

Soni

Vegh

et al. 2020

Front. Neurol.

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“…QSM images were reconstructed from Siemen’s magnitude and phase images using nonlinear dipole inversion [ 23 ] and MATLAB. To investigate for brain-wide changes in gray matter and white matter susceptibility we generated global gray and white matter masks based on an automated method that incorporates a stability mask [ 11 , 12 ]. Global grey and white matter masks were generated by first excluding voxels with R 2 * less than 1 ms −1 and greater than 65 ms −1 to remove large vessels such as the straight sinus from the final gray matter mask.…”

Section: Methodsmentioning

confidence: 99%

“…A stability mask was then constructed by computing coefficients of variability with an upper threshold of 0.8. White and gray matter were subsequently defined as χ < − 0.03 ppm and χ > 0.05 ppm, respectively and mean susceptibility values were then calculated for each [ 11 , 12 ].…”

Section: Methodsmentioning

confidence: 99%

“…Quantitative susceptibility mapping (QSM) is a comparatively new technique that utilizes MR phase images to map tissue susceptibility ( χ ) [ 9 ]. QSM is sensitive to diamagnetic and paramagenetic biomaterials including, among others, ferritin, hemosiderin, myelin and calcium [ 9 , 10 ] and has shown promise in assessing grey and white matter susceptiblity changes acutely following SRC [ 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

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Sub-acute Changes on MRI Measures of Cerebral Blood Flow and Venous Oxygen Saturation in Concussed Australian Rules Footballers

2022

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Background Sports-related concussion (SRC) is common in collision sport athletes. There is growing evidence that repetitive SRC can have serious neurological consequences, particularly when the repetitive injuries occur when the brain has yet to fully recover from the initial injury. Hence, there is a need to identify biomarkers that are capable of determining SRC recovery so that they can guide clinical decisions pertaining to return-to-play. Cerebral venous oxygen saturation (SvO2) and cerebral blood flow (CBF) can be measured using magnetic resonance imaging (MRI) and may provide insights into changing energy demands and recovery following SRC. Results In this study we therefore investigated SvO2 and CBF in a cohort of concussed amateur Australian Football athletes (i.e., Australia’s most participated collision sport). Male and female Australian footballers (n = 13) underwent MRI after being cleared to return to play following a mandatory 13-day recovery period and were compared to a group of control Australian footballers (n = 16) with no recent history of SRC (i.e., > 3 months since last SRC). Despite the concussed Australian footballers being cleared to return to play at the time of MRI, we found evidence of significantly increased susceptibility in the global white matter (p = 0.020) and a trend (F5,21 = 2.404, p = 0.071) for reduced relative CBF (relCBF) compared to the control group. Further, there was evidence of an interaction between sex and injury in straight sinus susceptibility values (F1,25 = 3.858, p = 0.061) which were decreased in female SRC athletes (p = 0.053). Of note, there were significant negative correlations between straight sinus susceptibility and relCBF suggesting impaired metabolic function after SRC. Conclusions These findings support the use of quantitative susceptibility mapping (QSM) and relCBF as sensitive indicators of SRC, and raise further concerns related to SRC guidelines that allow for return-to-play in less than two weeks.

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“…Experiments used a GE Healthcare Discovery MR750 3.0T system (GE Healthcare, Waukesha WI) with a 32‐channel head receive coil (Nova Medical, Wilmington MA). Data from five participants enrolled in a larger study of sport concussion 34 were preserved for off‐line reconstruction. Imaging parameters included: 30 ms TE, 800 ms TR, 503 repetitions, a 50° flip angle, 104 × 104 acquisition matrix, 63% partial Fourier encoding, 20.8 cm sagittal field of view, 2 mm thick slices, 8‐band simultaneous multi‐slice acceleration,

\frac{1}{3}

blipped‐CAIPI field of view shift, and 64 total slices, harmonized with the Lifespan Human Connectome Project acquisition protocol 35 .…”

Section: Methodsmentioning

confidence: 99%

Split‐slice training and hyperparameter tuning of RAKI networks for simultaneous multi‐slice reconstruction

Nencka

Arpinar

Bhave

et al. 2020

Magnetic Resonance in Med

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Simultaneous multi-slice acquisitions are essential for modern neuroimaging research, enabling high temporal resolution functional and high-resolution q-space sampling diffusion acquisitions. Recently, deep learning reconstruction techniques have been introduced for unaliasing these accelerated acquisitions, and robust artificial-neural-networks for k-space interpolation (RAKI) have shown promising capabilities. This study systematically examines the impacts of hyperparameter selections for RAKI networks, and introduces a novel technique for training data generation which is analogous to the split-slice formalism used in slice-GRAPPA. Methods: RAKI networks were developed with variable hyperparameters and with and without split-slice training data generation. Each network was trained and applied to five different datasets including acquisitions harmonized with Human Connectome Project lifespan protocol. Unaliasing performance was assessed through L1 errors computed between unaliased and calibration frequency-space data. Results: Split-slice training significantly improved network performance in nearly all hyperparameter configurations. Best unaliasing results were achieved with three layer RAKI networks using at least 64 convolutional filters with receptive fields of 7 voxels, 128 single-voxel filters in the penultimate RAKI layer, batch normalization, and no training dropout with the split-slice augmented training dataset. Networks trained without the split-slice technique showed symptoms of network over-fitting. Conclusions: Split-slice training for simultaneous multi-slice RAKI networks positively impacts network performance. Hyperparameter tuning of such reconstruction networks can lead to further improvements in unaliasing performance.

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Quantitative Susceptibility Mapping after Sports-Related Concussion

Cited by 24 publications

References 33 publications

Combined Diffusion Tensor Imaging and Quantitative Susceptibility Mapping Discern Discrete Facets of White Matter Pathology Post-injury in the Rodent Brain

Combined Diffusion Tensor Imaging and Quantitative Susceptibility Mapping Discern Discrete Facets of White Matter Pathology Post-injury in the Rodent Brain

Sub-acute Changes on MRI Measures of Cerebral Blood Flow and Venous Oxygen Saturation in Concussed Australian Rules Footballers

Split‐slice training and hyperparameter tuning of RAKI networks for simultaneous multi‐slice reconstruction

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