Concussions and Diffusion Tensor Imaging
Today we will be discussing concussions and the importance of Diffusion Tensor Imaging with standard MRI’s along with other modalities.
Concussions and Invisible Injuries
Have you ever seen your doctor, shared the symptoms that were bothering you, and were told, that “it is just in your head”? That can be such a frustrating experience! However, in the case of concussions and traumatic brain injuries, it is physiologically true!
The problem does lie in the brain but up until the last few years, the problem has been invisible. Flummoxed neurologists threw up their hands and inevitably left patients to suffer the symptoms. It is as though the marks of concussion and other brain injuries were written with invisible ink.
Diffusion Tensor Imaging MRI’s and the Corpus Collosum
Today we have more MRI advancements that help to make these invisible injuries visible! Diffusion Tensor Imaging is a sort of decoding serum that allows these kinds of injuries to be identified.
When Diffusion Tensor Imaging (DTI) is added to the MRI, it shows what the white matter (the corpus callosum) of the brain looks like on a microstructural level.
Image from doctorsimaging.com
The corpus callosum is part of the limbic system and is a bundle of nerves that connect the left and right hemispheres of our brain physiologically. This connection allows for the white matter to send messages back and forth from one side of the brain to the other and vice versa.
(Image by The Awkward Yeti)
Once this DTI technology became available, researchers started studying the white matter of the brain and discovered abnormalities in the brains of those with brain injuries and concussion symptoms!
Because the DTI looks at these microstructures of the corpus callosum, the injury becomes visible! The invisible ink reappears.
White matter in a DTI scan. Image by Cedar Sinai.
Another interesting aspect of concussions is that only half of everyone who experiences a concussion will have symptoms of post-concussion syndrome.
Does that mean that asymptomatic (asymptomatic-not experiencing symptoms) patients are out of danger?
A study was done to determine when a post-concussive sports player could return to the game. Should we allow the asymptomatic player to play again when they feel that they are back to normal, or should we take into account micro-changes to the brain?
Photo by Ben Hershey on Unsplash
What they found in this study was that 11 of the 82 post-concussive but asymptomatic players that went back to the game experienced a second concussion within a year.
Physically, the players felt like they had recovered, but physiologically, they had not recovered and were more prone to further concussive incidents. At this point, the injury is not invisible, but the symptoms can be!
Additionally, another study was done, this time involving military service members. This study was composed of:
Service members that had experienced concussions due to a blast,
Other service members who had sustained concussions in combat,
A blast control group,
and a non-blast control group.
They studied these service members using MRI with diffusion tensor imaging, and a high resolution structural image, at the time of injury, one year later and then again five years later.
Interestingly, at the one year post-injury mark, the brains of the service members looked as though they had fully recovered, but at five years, a further decrease in brain density was found. As we shared in a prior newsletter, brain density is important for optimal brain function.
This decrease in brain volume could explain why some of our military personnel start to experience PTSD, depression, dizziness, and/or emotional dysregulation long after the concussion or brain injury occurred.
Research is finding that there are stretching forces that occur in the corpus callosum during a concussion that affect areas of the brain, even though the effects are not always immediately evident. Thus, putting athletes back in the game before they are physiologically ready after this stretching force has occurred can lead to further concussions and damage to the brain.
This phenomena is also shown in a study regarding white matter abnormalities in sports-related concussion, even after six months. In this study, they used MR Spectroscopy (often called an MRS)
An MR Spectroscopy measures the chemical composition (inflammatory mediators) of the sections of the brain. It is another tool that can be used to see a more complete picture of what is occurring in the brain due to injury.
Between the MR Spectroscopy, which measures the inflammatory mediators of the brain, combined with Diffusion Tensor Imaging, that studies the microstructure of the brain’s white matter, we can see a clear picture of what was invisible.
Furthermore, another study found that high or low levels of inositol, (naturally occurring carbohydrate that mainly affects levels of neurotransmitters, and the way glucose is used by the body) can alter the microstructure of the brain and how the brain functions during the recovery of the concussion.
In light of this, it is imperative to also monitor inflammation levels in the brain, as well as note the micro-changes in the white matter and the density of sections of the brain.
Serum Neurofilament Light Chains
One final tool that can be used when digging into the post-concussive brain is Serum Neurofilament light chains. They are drawn by bloodwork to look at how much brain protein is in the blood. This information can be a biomarker for future brain volume loss and the progression of abnormal white matter.
These proteins found in the blood can dive even deeper into what is going on in the brain. This paired with the Diffusion Tensor Imaging which shows the inflamed white matter, tells a story that would otherwise be invisible except for the symptoms a post-concussive patient may be having.
MRI, Diffusion Tensor Imaging, Volumetric scans, (which we discussed in the last newsletter,) MR Spectroscopy, and drawing serum neurofilament light chains, are all tools that when used jointly, can paint a vivid picture of a brain injury on what was previously a blank canvas.
Here at Gates Brain Health, we incorporate these modalities to bring to light what was invisible in our brain injury and concussion patients. We fully believe that our patient’s symptoms are not imagined and that there are root causes and physiological issues to be addressed and healed. Similar to how a person would work with a personal trainer at a gym to determine the best specific exercises, diet, and lifestyle changes to meet their goals; our patients work with us to rehabilitate and re-build the density of their brain through neuroplasticity exercises, diet, and lifestyle changes to reduce stress and promote healing.
If you have any questions regarding Diffusion Tensor Imaging, or are ready to begin your path to healing, contact us at (775) 507-2000 or email firstname.lastname@example.org
By: Gemma Ward from information shared by Dr. Gates at https://www.youtube.com/watch?v=0JGah_FVNmY