Diffusion Tensor Brain MRI in the Detection of Structural Abnormality of the White Substance in Concussion

Concussions in sports are a major public health problem because of their frequency, and are often underdiagnosed because of an unspecific clinical picture or sometimes masked by the concussion itself. Support data has been constantly evolving in recent years, including the last publication of the Berlin Consensus in 2016 specifying support in the field. However, to date, there is no tool to predict the severity of a concussion or to predict when it will return to play objectively and reliably. Brain MRI done after the head injury is most often normal. However, previous studies agree that there is a persistent electrophysiologic disturbance several weeks after the injury, and the specific pathophysiology of white matter changes after a head injury remains controversial. Diffusion tensor imaging (DTI), in addition to morphological sequences, is capable of assessing white matter microstructure and fibrous tract integrity or not. Several parameters, such as the seemingly normal white matter fractional anisotropy (FA) coefficient, the mean diffusivity and the radial diffusivity, may be altered in the aftermath of a concussion, indicating axonal damage not visible on conventional MRI sequences. Previous studies have evaluated these parameters with sometimes contradictory results: some have found an increase in AF in specific regions such as the cortico-spinal tract and the corpus callosum, others have found a decrease in AF. So far, assessment of a player's condition on and off the field after a head injury has been based on clinical criteria alone, sometimes far too subjective. The player may choose to mask their symptoms to allow them to return to the game faster, or feign more than they have. Once pathologies such as bone fractures or intracranial hematomas are ruled out by conventional imaging, there is no longer any tool for a more accurate diagnosis of possible microstructural alterations of brain tissue and for monitoring of the patient. The advent of new MRI