Defining an Analytic Framework to Evaluate Quantitative MRI Markers of Traumatic Axonal Injury: Preliminary Results in a Mouse Closed Head Injury Model.

Diffuse axonal injury (DAI) is a hallmark of traumatic brain injury (TBI) pathology. Recently, the Closed Head Injury Model of Engineered Rotational Acceleration (CHIMERA) was developed to generate an experimental model of DAI in a mouse. The characterization of DAI using diffusion tensor magnetic resonance imaging (MRI; diffusion tensor imaging, DTI) may provide a useful set of outcome measures for preclinical and clinical studies. The objective of this study was to identify the complex neurobiological underpinnings of DTI features following DAI using a comprehensive and quantitative evaluation of DTI and histopathology in the CHIMERA mouse model. A consistent neuroanatomical pattern of pathology in specific white matter tracts was identified across ex vivo DTI maps and photomicrographs of histology. These observations were confirmed by voxelwise and regional analysis of DTI maps, demonstrating reduced fractional anisotropy (FA) in distinct regions such as the optic tract. Similar regions were identified by quantitative histology and exhibited axonal damage as well as robust gliosis. Additional analysis using a machine-learning algorithm was performed to identify regions and metrics important for injury classification in a manner free from potential user bias. This analysis found that diffusion metrics were able to identify injured brains almost with the same degree of accuracy as the histology metrics. Good agreement between regions detected as abnormal by histology and MRI was also found. The findings of this work elucidate the complexity of cellular changes that give rise to imaging abnormalities and provide a comprehensive and quantitative evaluation of the relative importance of DTI and histological measures to detect brain injury.

Video analysis of craniofacial soccer incidents: a prospective study.

OBJECTIVE: The aim of this study was to assess the occurrence of incidents involving the craniofacial region during Brazilian Professional Soccer League matches. The mechanisms of these incidents and the association between their characteristics and severity were also analyzed. DESIGN: Prospective Epidemiology Study. METHODS: A total of 113 first division matches of the Brazilian Soccer League were analyzed in 2009. Data collected included incident type, site affected, causing agent, severity, player position, field zone, referee decision and time of the match when the incident took place. Descriptive analysis considered absolute and relative frequencies and 95% confidence intervals. Fisher Exact Tests were used to test associations (p≤0.05). RESULTS: Out of all matches, in 84.1% at least one craniofacial region related incident happened, totaling 227 incidents (mean of 2.0 per match). With reference to incident mechanisms and characteristics, 91.2% were hits and the most affected site was the face (70.0%). The most frequent causing agent was the upper extremity (59.5%) and the most frequently affected player was the striker (31.7%). The incident severity was associated with player position (p<0.01), the causing agent (p<0.01), field zone (p<0.01), site affected (p=0.03) and incident type (p<0.01). CONCLUSIONS: Soccer presented a high number of incidents against head and face during professional practice in Brazil, representing a real risk to athletes. Preventive strategies should be focused on game rule observance and "fair play".