Tracing Lines and Saving Lives:
Using High-Definition Fiber Tracking to Find the Brain’s “Broken Cables”
Imagine holding this ball of yarn… Without unraveling it, try to follow each thread... Trace its path, and see how many times a thread reappears in the same area. Are you sure it’s the same one?!
As if that task wasn’t hard enough, now imagine wedging a pair of scissors into the yarn ball, and cutting a few threads at random. After removing the scissors, can you tell which threads you cut?
For University of Pittsburgh psychologist Walter Schneider and his neurosurgeon collaborators, David Okonkwo and Juan Fernandez-Miranda, their newly developed imaging technique - high-definition fiber tracking (HDFT) - allows them see where those scissors cut inside the largest, most complicated yarn ball imaginable: the human brain!
In 2010, about 2.5 million visits to the emergency room, hospitalizations, or deaths were associated with traumatic brain injuries (TBIs) in the United States. Although TBIs are disturbingly common among our nation’s veterans and professional athletes, they occur in the general population more often than you might think. According to the Centers for Disease Control and Prevention (CDC), falls accounted for 40% of all TBIs in the U.S. between 2006 and 2010, and automobile accidents were the third-largest cause of TBIs, at just over 14%.
For people who suffer with TBIs, everyday life is often challenging. Even basic tasks like reading and walking can become impossible. For the patients’ friends and family, drastic personality changes caused by damage to the brain’s emotion and reasoning areas may turn their best friend, father, or husband into an unpredictable – even violent - stranger.
Perhaps the saddest part of the story for TBI patients and their families is just how difficult it is to identify the neurological causes of their injuries. That is, when they were in that car accident, or fell off that ladder, where did the scissors cut? What “threads” inside their brain were severed, and how can that explain their poor memory, or emotional outbursts?
Until Schneider and colleagues developed HDFT, it was extremely difficult to answer those questions. Although doctors used technology like CT scanning and diffusion tensor imaging (DTI) to look at the brains of TBI patients, the damage to the brain was “invisible” with that technology, and the patients went home with a “clean” bill of health. Now with HDFT, neurologists can see all 40 of the major tracts in a patients’ brain. This allows them to diagnose exactly which connections were damaged in a TBI to develop appropriate treatment.
For TBI patients and their families, HDFT visualization provides them with the answers they desperately seek. As explained in a Discover magazine article about HDFT, neurologists can even use an iPad® app to show a patient their own brain scans. By looking at the scans, patients and their families can see precisely what is wrong to better understand their mysterious TBIs.
HDFT also guides therapeutic approaches to make daily life better for TBI patients. After a physician understands which pathways in their patients’ brain are impaired, they can help their patient function better using alternative pathways. For one Army veteran whose TBI made reading difficult, a member of Schneider’s team suggested that he read while listening to music, and tapping out the words in time to the beat. Although the veteran admits that it looks like he’s “cutting a rap record” when he’s reading, the technique has proven effective, thanks to an accurate HDFT scan that indicated to the veteran’s doctors exactly which circuits were still intact and fully functional.
While HDFT is new, and some researchers question how accurately it can quantify impaired brain circuitry, the technology’s impact on the lives of TBI patients and their families is undeniable. As scientists and physicians call for improvements in existing neuroimaging technologies like DTI, High-Definition Fiber Tracking will become a critical tool for solving the brain’s most “unsolvable” mysteries.
Centers for Disease Control and Prevention National Center for Injury Prevention and Control, Division of Unintended Injury Prevention. (2015). Traumatic Brain Injury in the United States: Fact Sheet. Retrieved from http://www.cdc.gov/traumaticbraininjury/get_the_facts.html
Chmura, J., Presson, N., Benso, S., Puccio, A. M., Fissel, K., Hachey, R., . . . Schneider, W. (2015). A High-Definition Fiber Tracking Report for Patients With Traumatic Brain Injury and Their Doctors. Military Medicine, 180(3S), 122-134.
Farquharson, S., Tournier, J. D., Calamante, F., Fabinyi, G., Schneider-Kolsky, M., Jackson, G. D., & Connelly, A. (2013). White matter fiber tractography: why we need to move beyond DTI. Journal of Neurosurgery, 118(6), 1367-1377.
Fernandez-Miranda, J. C., Pathak, S., Engh, J., Jarbo, K., Verstynen, T., Yeh, F.-C., . . . Friedlander, R. (2012). High-Definition Fiber Tractography of the Human Brain: Neuroanatomical Validation and Neurosurgical Applications. Neurosurgery, 71(2), 430-453.
Thomas, C., Ye, F. Q., Irfanoglu, M. O., Modi, P., Saleem, K. S., & Leopold, D. A. (2014). Anatomical accuracy of brain connections derived from diffusion MRI tractography is inherently limited. Proceedings of the National Academy of Sciences, 111(46), 16574-16579.
Trivedi, B. P. (2015). Seeing the Brain's Broken Cables. Retrieved from http://discovermagazine.com/2015/sept/16-broken-cables