Recent studies show that MRI might be more useful in the long-term evaluation of traumatic brain injury (TBI), also known as a concussion. The current action plan for medical evaluation has doctors assessing symptoms and sometimes ordering a CT scan. This is due to the fact that CT's are more widespread and take less time than MRI's. However, MRI can show more information about lesions and structural integrity in the brain in regards to child abuse and combat brain injuries.
What is traumatic brain injury?
Traumatic brain injury is usually caused by an impact to the head or body or penetration of brain tissue.1 This can be caused by falls, car accidents, violence, sports, combat injuries, or explosive blasts.2 TBI can be mild to severe depending on the injury. Mild TBI (mTBI) can be understood as what the typical concussion is: a temporary change in thinking and acting. Severe TBI, referred to as just TBI, is characterized by a loss of consciousness or amnesia after the injury. Injuring the brain can cause problems thinking, focusing, speaking, and much more.
How MRI improves the understanding of TBI
Although CT scans are done first, MRI shows information that cannot be picked up by CT.3 MRI can show internal bleeding and bruising or scarring in brain tissue. These are both signs of injury to the patient's nerve fibers and can explain continuing or worsening symptoms. More advanced methods, as described below, can show the brain structure and regions where dead or injured tissue is reabsorbed causing atrophy, which can be seen less accurately on a CT scan.4
Head trauma due to abuse
Phoenix Children's Hospital conducted a retrospective study of 105 children ranging in age from infancy to 21 years old who experienced TBI from child abuse.4 All of these children were in the pediatric trauma center between 2008 and 2010. Each child had an initial CT exam followed by an MRI scan within two weeks. The study found that MR imaging detected nearly four times as many brain tissue lesions compared to CT imaging. Of the 105 patients, only eight had normal CT scans, and six of these eight patients had abnormal lesions on their MRI's.
Doctors may want to consider MRI as a follow up to or replacement of CT scans more often, if more abnormalities show up on MRI as this study suggests.
Head trauma due to combat
The VA Medical Center in Philadelphia conducted a study of 57 veterans who experienced mTBI during combat.5 In such cases, doctors may have difficulty differentiating mTBI effects from those of other conditions such as PTSD. Conventional MRI showed normal results, with no mention of CT to compare to. However, advanced MR techniques provided even more data that was useful for the physicians.
Over the course of about a year, the VA Medical Center was able to monitor differences in the white matter integrity using diffusion tensor imaging (DTI). DTI measures diffusion to create a virtual map of the brain's structure. The study found that DTI may be able to help predict long-term outcomes of mTBI, especially since it has been helpful in regards to short-term functional outcomes. Of the 57 veterans, 34 were able to return to work.
"Veterans who were not able to return to work displayed significantly lower fractional anisotrophy and high diffusivity in the left internal capsule," writes HealthManagement.org. In simpler terms, this means that there was less structural integrity and higher concentration of liquid in a region of the brain that provides important motor stimulation. The results showed a direct correlation between loss of white matter integrity, fine motor function, and ability to return to work.
In mild cases, doctors should consider using a conventional MRI instead of CT to monitor abnormalities. MRI allows the doctor to see additional brain lesions that do not appear on CT. Additionally, they can judge whether they are abnormal. In extreme cases, doctors should consider using DTI rather than a conventional MRI to better predict outcomes and provide precise care. DTI allows the doctor to get a clear image of what damage was done and how it will affect the patient's ability to live and work. If doctors were to combine conventional MRI and DTI MRI, they could monitor the lesions, the damage and any change to the patient's functionality.
1. "Basic Information about Traumatic Brain Injury and Concussion." CDC. 2010. Web. 15 October 2018. https://www.cdc.gov/traumaticbraininjury/basics.html>.
2. "Traumatic brain injury." MayoClinic.org. Web. 15 October 2018. <https://www.mayoclinic.org/diseases-conditions/traumatic-brain-injury/symptoms-causes/syc-20378557>.
3. "Traumatic Brain Injury (TBI) and Concussion." asnr.org. 2012. Web. 3 October 2018. <https://www.asnr.org/patientinfo/conditions/tbi.shtml>.
4. Staff News Brief. "Advantages of MRI for lesion detection in pediatric traumatic brain injury." Applied Radiology. 19 March 2015. Web. 2 October 2018. <https://appliedradiology.com/articles/advantages-of-mri-for-lesion-detection-in-pediatric-traumatic-brain-injury>.
5. "MRI-Type Imaging Predicts Impact From Combat Brain Injury." HealthManagement.org. 4 April 2016. Web. 2 October 2018. <https://healthmanagement.org/c/imaging/news/mri-type-imaging-predicts-impact-from-combat-brain-injury>.