Imaging Characterization of the Biomechanical Coupling of Brain and Skull

Background: Traumatic brain injury (TBI) affects over 1.7 million people in the United States each year. Many cases are mild, but people with a history of TBI may have long-term symptoms; they are also known to be more susceptible to future concussions. Researchers are working to understand how TBI affects tissues in and around the brain over the long term. This natural history study will investigate how a TBI may change the stiffness of the brain and its surrounding connective tissues. Objective: To see how the brain and connective tissues respond to small head movements in people with and without a prior TBI. Eligibility: People aged 21 to 65 years with a history of TBI. People with no history of TBI are also needed. Design: Participants will have 1 clinic visit that will last about 4 hours. Participants will have a physical exam. They answer questions to make sure it is safe for them to have a magnetic resonance imaging (MRI) scan of their brain. They will have an MRI scan in 2 parts. During the first part, participants will lie on a table that slides into a large tube. They will hear loud knocking noises. They may wear earplugs or earmuffs. They will lie still for 15 minutes at a time. They will be in the tube for about up to 75 minutes. The second part is called magnetic resonance elastography (MRE). Participants will lie with their head on a pillow that vibrates gently. This test will take 10 minutes. Participants will answer questions about how they feel 1 or 2 days after the procedure.