Diffusion measures indicate fight exposure-related damage to cerebral white matter in boxers and mixed martial arts fighters.

BACKGROUND AND PURPOSE: Traumatic brain injury is common in fighting athletes such as boxers, given the frequency of blows to the head. Because DTI is sensitive to microstructural changes in white matter, this technique is often used to investigate white matter integrity in patients with traumatic brain injury. We hypothesized that previous fight exposure would predict DTI abnormalities in fighting athletes after controlling for individual variation. MATERIALS AND METHODS: A total of 74 boxers and 81 mixed martial arts fighters were included in the analysis and scanned by use of DTI. Individual information and data on fight exposures, including number of fights and knockouts, were collected. A multiple hierarchical linear regression model was used in region-of-interest analysis to test the hypothesis that fight-related exposure could predict DTI values separately in boxers and mixed martial arts fighters. Age, weight, and years of education were controlled to ensure that these factors would not account for the hypothesized effects. RESULTS: We found that the number of knockouts among boxers predicted increased longitudinal diffusivity and transversal diffusivity in white matter and subcortical gray matter regions, including corpus callosum, isthmus cingulate, pericalcarine, precuneus, and amygdala, leading to increased mean diffusivity and decreased fractional anisotropy in the corresponding regions. The mixed martial arts fighters had increased transversal diffusivity in the posterior cingulate. The number of fights did not predict any DTI measures in either group. CONCLUSIONS: These findings suggest that the history of fight exposure in a fighter population can be used to predict microstructural brain damage.

Factors associated with early magnetic resonance imaging utilization for acute occupational low back pain: a population-based study from Washington State workers' compensation.

STUDY DESIGN: A population-based, prospective cohort study. OBJECTIVE: To identify demographic, job-related, psychosocial, and clinical factors associated with the use of magnetic resonance imaging (MRI) within 6 weeks from injury (early MRI) among workers' compensation claimants with acute occupational low back pain (LBP). SUMMARY OF BACKGROUND DATA: Early MRI may be associated with increased use of services for treatment and costs. To understand utilization and most appropriately apply guidelines, it is important to identify factors associated with early imaging use for occupational LBP. METHODS: Workers (N = 1830) were interviewed 3 weeks (median) after submitting a workers' compensation claim for a back injury. Demographic, work, health, clinical, and injury characteristics were ascertained from interviews, medical records, and administrative data. Modified Poisson regression analyses identified factors associated with early MRI use. RESULTS: Among respondents, 362 (19.8%) received an early MRI. Multivariable regression showed that male workers were 43% more likely to receive an early MRI than female workers (incident rate ratio [IRR]: 1.43, 95% confidence interval [CI]: 1.12-1.82). Initial visit type with a surgeon was associated with 78% greater likelihood of receiving an early MRI than that with a primary care physician (IRR: 1.78, 95% CI: 1.08-2.92). Having a chiropractor as the initial provider was associated with a reduced likelihood of early MRI (IRR: 0.53, 95% CI: 0.42-0.66). Workers with elevated work fear-avoidance, higher Roland scores, or increased injury severity were more likely to receive early MRI than counterparts with lower levels or scores. CONCLUSION: Nearly 20% of the injured workers with LBP receive early MRI, a rate similar to that reported elsewhere. Early MRI may lead to greater subsequent interventions, potentially poorer outcomes, and increased health care expenditures. On the basis of the characteristics of patients with uncomplicated occupational LBP, providers may be able to provide tailored care, and providers and policy makers may better understand the utilization of imaging and adherence to clinical guidelines.