Neuroimaging in repetitive brain trauma

Abstract

Sports-related concussions are one of the major causes of mild traumatic brain injury. Although most patients recover completely within days to weeks, those who experience repetitive brain trauma (RBT) may be at risk for developing a condition known as chronic traumatic encephalopathy (CTE). While this condition is most commonly observed in athletes who experience repetitive concussive and/or subconcussive blows to the head, such as boxers, football players, or hockey players, CTE may also affect soldiers on active duty. Currently, the only means by which to diagnose CTE is by the presence of phosphorylated tau aggregations post-mortem. Non-invasive neuroimaging, however, may allow early diagnosis as well as improve our understanding of the underlying pathophysiology of RBT. The purpose of this article is to review advanced neuroimaging methods used to investigate RBT, including diffusion tensor imaging, magnetic resonance spectroscopy, functional magnetic resonance imaging, susceptibility weighted imaging, and positron emission tomography. While there is a considerable literature using these methods in brain injury in general, the focus of this review is on RBT and those subject populations currently known to be susceptible to RBT, namely athletes and soldiers. Further, while direct detection of CTE in vivo has not yet been achieved, all of the methods described in this review provide insight into RBT and will likely lead to a better characterization (diagnosis), in vivo, of CTE than measures of self-report.

Age of first exposure to tackle football and chronic traumatic encephalopathy

“…15 RHI, in general, is associated with macro- and microstructural, neurochemical, and functional brain alterations. 47 Future work, including experimental animal models, is needed to study mechanisms that underpin the association between youth exposure to RHI and worse clinical function later in life.…”

In vivo imaging of neuroinflammation in schizophrenia

“…There are several advances in the MRS acquisition and analysis field that allow for better coverage, potentially smaller regions of interest and better spectral resolution, which could improve sensitivity and specificity of MRS (Ng et al, 2014; Posse et al, 2013). These newer more sophisticated acquisition methods utilize additional excitation pulses and scan time can now provide information regarding spatial variations of metabolite within a large region of interest (chemical shift imaging).…”

Cavum Septi Pellucidi in Symptomatic Former Professional Football Players

“…24 Increased rates of CSP have also been reported among boxers and participants of other contact-sports exposed to repetitive head impacts. 15,25 In addition, recent studies suggest a possible causal relationship between repetitive head impacts and CSP. Aviv and colleagues, 26 for example, studied 164 active boxers who underwent annual magnetic resonance imaging (MRI) for a boxing board license renewal.…”

“…13 One of the main problems in diagnosing CTE in vivo is the current lack of clinical biomarkers. 14,15 A noninvasive imaging biomarker may, however, make it possible to diagnose CTE during life, which could pave the way for developing therapeutic interventions to prevent further neurodegenerative changes and/or to selectively treat the symptoms of this disease.…”