Imaging Tests

Although not commonly used for diagnosing mild traumatic brain injury, neuroradiological tests using computer-assisted brain scans can help doctors visualize damage to the brain. These imaging tests can include:

CT Scan: The most common imaging test is computerized axial tomography, called a CT or CAT scan. This scan produces a series of images that show cross-sections of the brain. CT scans can detect physical changes in the brain such as hematomas and swelling, which may require immediate treatment. CT scans appear normal in patients with mild TBI.

MRI: Another useful diagnostic test for TBI is magnetic resonance imaging, or MRI, which uses a large magnet and radio waves to generate computerized images of the brain without exposing the patient to x-ray radiation. MRIs produce high-resolution images of brain structures and are painless. MRI results, like CT scans, appear normal in patients with mild TBI.

X-rays, MRIs, and CT scans can detect fractures, hemorrhages, swelling, and certain kinds of tissue damage, but they do not always detect traumatic brain injury. This is because TBI, especially in its milder forms, often involves subtle trauma to the brain that causes chemical and physical changes to brain tissues rather than structural damage. These changes often cannot be found with standard imaging procedures.

More sophisticated imaging techniques that measure brain cell metabolism, such as single-photon emission computed tomography, called SPECT; positron emission tomography, called PET; or diffusion tensor imaging, called DTI, can help visualize subtle injuries, but rarely change the treatment plan. In other words, these tests can help providers to better understand the location and extent of the injury, but are not likely to change the approach to medical care. It is also important to note that these specialized neuroimaging techniques are more commonly used in research on mild TBIs.