A traumatic brain injury (TBI) occurs when an external force damages the brain, impairing the way it normally functions.
While a TBI diagnosis relies on multiple tests as well as a thorough clinical workup, traumatic brain injury MRI and CT screening are vital tools. TBI imaging is used to help doctors determine the severity of an injury, allowing them to exclude more serious forms of traumatic brain injury, such as intracranial hemorrhage. It is used to identify areas of damage and helps assess a patient’s risk of developing a secondary brain injury.
Whether TBI imaging is being performed for a loved one, such as your child, or yourself, these exams can be unfamiliar and even daunting. We spoke with neuroradiologist and pediatric subspecialty radiologist, Dr. Michael Rozenfeld, to learn the five most important things patients should know about their TBI imaging.
1. A second opinion can help ensure an accurate TBI diagnosis.
Brain imaging, especially when performed in the emergency setting, is often not interpreted by a fellowship-trained neuroradiologist. A second opinion can often uncover conditions that were missed, misinterpreted, or overdiagnosed.
2. TBI imaging of children should be read by a pediatric neuroradiologist.
Studies show that fellowship-trained neuroradiologists provide more accurate interpretations of brain imaging. In addition, neuroradiologists who completed an additional fellowship in pediatric neuroradiology have the specialized training required to accurately interpret the unique diagnoses seen in our younger patients.
3. There are some commonly missed findings when imaging is not read by a subspecialist.
Subtle findings of traumatic brain injury, including hemorrhage, contusion, fractures, and diffuse axonal injury are often missed by non-subspecialized radiologists.
4. Artificial intelligence can help improve diagnostic accuracy with TBI imaging.
Artificial intelligence, when combined with specialized techniques like diffusion tensor imaging, can provide unique insights into brain injuries. These techniques can allow more accurate quantification of injuries as well as provide clues to otherwise missed diagnoses.
5. TBI CT and TBI MRI exams each have unique benefits for traumatic brain injury diagnosis.
CT is often utilized in the emergent setting due to its speed and accuracy for detecting life-threatening injuries. It can, however, miss more subtle findings, such as contusions, small areas of hemorrhage, and diffuse axonal injury. In patients with persistent symptoms after a traumatic brain injury, MRI can provide additional diagnostic information.
Types of TBI
The severity of a TBI can be classified into one of three main categories:
- Mild TBI or concussion
- Moderate TBI
- Severe TBI
A TBI can be a closed brain injury or a penetrating brain injury. A closed brain injury occurs when there is a jolt or harsh bang to the skull. Sports injuries, car accidents, and falls are common causes of closed head injuries. A penetrating brain injury causes a break in the skull, such as a gunshot or stab.
Primary Brain Injury vs Secondary Brain Injury
A primary brain injury is an injury to the brain that occurs during the initial moment of trauma, such as a fall or a bullet entering the brain. A secondary brain injury happens over a period of time, hours or days, after the primary brain injury. This can be any change at a cellular or chemical level or a change in the tissues or blood vessels that results in further damage to the brain.
Diffuse Axonal Injury (DAI)
A diffuse axonal injury is tearing of the brain’s connecting nerve fibers (axons). DAI can be very difficult to detect, as these changes in the brain are often very small.
Intracranial Hematoma (ICH)
An intracranial hematoma is a blood clot or collection of blood in or around the brain. Intracranial hematomas are classified based on their location within the head. They range from mild, non-threatening TBIs to serious, emergent injuries.
A cerebral contusion, a bruise of the brain, is a type of intracranial hematoma. These bruises are scattered areas of bleeding on the surface of the brain that may cause swelling inside of the brain itself. A cerebral contusion may occur along with a fracture or other blood clots.
A skull fracture is a traumatic brain injury that causes a break in the skull bone. A skull fracture can be a closed fracture (meaning the skin that covers the fracture area is not broken) or an open fracture (where the skin is broken or cut).
Other types of skull fractures include:
- Linear skull fracture
- Depressed skull fracture
- Diastatic skull fracture
- Basilar skull fracture