Contact sports athletes, military personnel, and civilians that suffer from multiple head traumas have the potential to develop Chronic Traumatic Encephalopathy (CTE), a progressive, degenerative ...brain disease diagnosed only postmortem by characteristic tau deposition in the brain. There is, therefore, a need for in-vivo diagnosis for CTE to diagnose and manage this disease, while the individual is still alive. However, there is no definitive in-vivo diagnosis because of heterogeneous clinical symptoms that often overlap with other neurodegenerative diseases. Magnetic Resonance Spectroscopy (MRS) can be a suitable candidate for CTE diagnosis as multiple head trauma changes the neurochemicals in the brain that can be detected using MRS. These changes can be subtle, and group differences are not sufficient for clinical diagnosis. This paper proposes a machine learning based approach to capture the neuro-spectroscopic signatures corresponding to CTE-related impairments in NFL players. The classification model uses concentration estimates of metabolites to classify between 'Impaired and 'Non-impaired players. The model using the metabolite concentrations of creatine, choline, N-acetyl-aspartate, glutamate, and macromolecules achieved Area Under the Curve (AUC) of 0.72 and prediction accuracy of 75%. While these metabolites have been shown to be altered in previous concussion studies, other metabolites may improve the diagnostic accuracy. In order to include more metabolites, two-dimensional correlated spectroscopy (L-COSY), which resolves overlapping metabolites, was also acquired. The L-COSY model which included 15 metabolites, increased prediction accuracy to 87 % with AUC of 0.83. With the aid of machine learning, these metabolites may serve as potential biomarkers that correspond to the CTE-related impairments that will allow for CTE diagnostics in athletes prior to their death.
OBJECTIVES:The corpus callosum (CC) represents a key structure for hand motor development and is accessible to investigation by diffusion tensor magnetic resonance imaging (DTI) and transcranial ...magnetic stimulation (TMS). To identify quantifiable markers for motor development, we combined DTI with TMS.
MATERIALS AND METHODS:We examined groups of 11 healthy preschool-aged children, 10 healthy adolescents, and 10 healthy adults with both, DTI and TMS/ipsilateral silent period (iSP). DTI-values for fractional anisotropy (FA) were calculated for areas I to V of the CC. ISP-values for latency, duration, and extent of electromyography suppression were calculated.
RESULTS:FA was significantly lower in areas II to IV of the CC in children as compared with adults (P < 0.05). In area III, where callosal motor fibers cross the CC, FA differed significantly between children and adolescents (P < 0.05). TMS parameters demonstrated significant age-related differences in duration and extent of iSP (P < 0.05). No significant differences were detected regarding latency of iSP.
CONCLUSIONS:The maturation of callosal motor fiber connectivity seems to reflect the degree of interhemispheric inhibition between the motor cortices with anisotropy of callosal motor fibers being a potential marker for motor development.
The aim of this study was to examine the brain's white matter microstructure by using MR diffusion tensor imaging (DTI) in ice hockey players with a history of clinically symptomatic concussion ...compared with players without a history of concussion.
Sixteen players with a history of concussion (concussed group; mean age 21.7 ± 1.5 years; 6 female) and 18 players without a history of concussion (nonconcussed group; mean age 21.3 ± 1.8 years, 10 female) underwent 3-T DTI at the end of the 2011-2012 Canadian Interuniversity Sports ice hockey season. Tract-based spatial statistics (TBSS) was used to test for group differences in fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and the measure "trace," or mean diffusivity. Cognitive evaluation was performed using the Immediate Postconcussion Assessment and Cognitive Test (ImPACT) and the Sport Concussion Assessment Tool-2 (SCAT2).
TBSS revealed a significant increase in FA and AD, and a significant decrease in RD and trace in several brain regions in the concussed group, compared with the nonconcussed group (p < 0.05). The regions with increased FA and decreased RD and trace included the right posterior limb of the internal capsule, the right corona radiata, and the right temporal lobe. Increased AD was observed in a small area in the left corona radiata. The DTI measures correlated with neither the ImPACT nor the SCAT2 scores.
The results of the current study indicate that a history of concussion may result in alterations of the brain's white matter microstructure in ice hockey players. Increased FA based on decreased RD may reflect neuroinflammatory or neuroplastic processes of the brain responding to brain trauma. Future studies are needed that include a longitudinal analysis of the brain's structure and function following a concussion to elucidate further the complex time course of DTI changes and their clinical meaning.
Objective:
There is an on-going controversy about venous drainage abnormalities in multiple sclerosis (MS). We applied cardiac-gated phase-contrast and venographic magnetic resonance (MR) techniques ...to compare venous drainage patterns in patients with MS, healthy controls, and subjects with migraine.
Methods:
A total of 27 patients with MS (21 female, age 12–59 years, mean disease duration 8.4 ± 8.5 years) and 27 age- and gender-matched healthy controls (21 female, age 12–60 years) were investigated with velocity-encoded cine-phase contrast MR sequences and a 2D time-of-flight MR venography of the cervicocranial region on a 3-T MRI. The data were compared with 26 patients with chronic migraine headaches (19 female, age 17–62 years), previously investigated with the same protocol. The degree of primary and secondary venous outflow in relation to the total cerebral blood flow (tCBF) was compared both quantitatively and qualitatively. Statistical analyses were performed using linear regression models.
Results:
Secondary venous outflow was significantly increased in patients with MS compared with healthy controls, both qualitatively (p < 0.001) and quantitatively (p < 0.013). The observed changes were independent of age and disease duration. Very similar alterations of venous drainage were detectable with the same approach in patients with migraine, without significant differences between MS and migraine patients (p = 0.65).
Conclusion:
Our MRI-based study suggests that patients with MS have alterations of cerebral venous drainage similar to subjects with chronic migraine. These non-disease-specific changes seem to a secondary phenomenon rather than being of primary pathogenic importance.
•Classifying PTSD from trauma-unexposed healthy controls (HC) using three imaging modalities performed well (∼75 % AUC), but performance suffered markedly when classifying PTSD from trauma-exposed ...healthy controls (TEHC) using three imaging modalities (∼60 % AUC).•Using deep learning for feature reduction (denoising variational auto-encoder; DVAE) dramatically reduced the number of features with no concomitant performance degradation.•Utilizing denoising variational autoencoder (DVAE) models improves generalizability across heterogeneous multi-site data compared with the traditional machine learning frameworks.
Recent advances in data-driven computational approaches have been helpful in devising tools to objectively diagnose psychiatric disorders. However, current machine learning studies limited to small homogeneous samples, different methodologies, and different imaging collection protocols, limit the ability to directly compare and generalize their results. Here we aimed to classify individuals with PTSD versus controls and assess the generalizability using a large heterogeneous brain datasets from the ENIGMA-PGC PTSD Working group.
We analyzed brain MRI data from 3,477 structural-MRI; 2,495 resting state-fMRI; and 1,952 diffusion-MRI. First, we identified the brain features that best distinguish individuals with PTSD from controls using traditional machine learning methods. Second, we assessed the utility of the denoising variational autoencoder (DVAE) and evaluated its classification performance. Third, we assessed the generalizability and reproducibility of both models using leave-one-site-out cross-validation procedure for each modality.
We found lower performance in classifying PTSD vs. controls with data from over 20 sites (60 % test AUC for s-MRI, 59 % for rs-fMRI and 56 % for d-MRI), as compared to other studies run on single-site data. The performance increased when classifying PTSD from HC without trauma history in each modality (75 % AUC). The classification performance remained intact when applying the DVAE framework, which reduced the number of features. Finally, we found that the DVAE framework achieved better generalization to unseen datasets compared with the traditional machine learning frameworks, albeit performance was slightly above chance.
These results have the potential to provide a baseline classification performance for PTSD when using large scale neuroimaging datasets. Our findings show that the control group used can heavily affect classification performance. The DVAE framework provided better generalizability for the multi-site data. This may be more significant in clinical practice since the neuroimaging-based diagnostic DVAE classification models are much less site-specific, rendering them more generalizable.
The majority of traumatic encephalopathy syndrome (TES) cases have been reported in former contact sport athletes. This is the first case with TES in a 19-year-old male patient with progressive ...cognitive decline after daily domestic physical violence through repeated hits to the head for 15 years. The patient presented with a moderate depressive episode and progressive cognitive decline. Tau positron emission tomography (PET) with 220 MBq of 18FPI-2620 revealed increased focal signal at the frontal and parietal white/gray matter border. Brain magnetic resonance imaging (MRI) showed a cavum septum pellucidum, reduced left-sided hippocampal volume, and a left midbrain lesion. Cerebrospinal fluid results showed elevated total and p-tau. Neurocognitive testing at admission showed memory deficits clearly below average, and hampered dysfunctions according to the slow processing speed with a low mistake rate, indicating the acquired, thus secondary, attentional deficits. We diagnosed the patient with a TES suggestive of chronic traumatic encephalopathy and classified him as having subtle/mild functional limitation with a most likely transition to mild dementia within the TES criteria. This report underlines child abuse as a relevant criterion in diagnosing TES in cases with repetitive hits to the head. In addition to clinical markers, we show the relevance of fluid tau biomarkers and tau-PET to support the diagnosis of TES according to the recently published diagnosis criteria for TES.
Repetitive head impacts (RHI) are commonly observed in athletes participating in contact sports such as American football, ice hockey, and soccer. RHI usually do not result in acute symptoms and are ...therefore often referred to as subclinical or subconcussive head impacts. Epidemiological studies report an association between exposure to RHI and an increased risk for the development of neurodegenerative diseases. Diffusion magnetic resonance imaging (dMRI) has emerged as particularly promising for the detection of subtle alterations in brain microstructure following exposure to sport-related RHI. The purpose of this study was to perform a systematic review of studies investigating the effects of exposure to RHI on brain microstructure using dMRI. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to determine studies that met inclusion and exclusion criteria across three databases. Seventeen studies were identified and critically evaluated. Results from these studies suggest an association between white matter alterations and RHI exposure in youth and young adult athletes. The most consistent finding across studies was lower or decreased fractional anisotropy (FA), a measure of the directionality of the diffusion of water molecules, associated with greater exposure to sport-related RHI. Whether decreased FA is associated with functional outcome (e.g., cognition) in those exposed to RHI is yet to be determined. This review further identified areas of importance for future research to increase the diagnostic and prognostic value of dMRI in RHI and to improve our understanding of the effects of RHI on brain physiology and microstructure.
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