Neuroimaging, a key role in diagnosis of diffuse axonal injury. CT and MRI patterns every radiologist should know

Abstract

Learning objectives - to understand the common mechanisms and pathology of diffuse axonal injury (DAI) - to recognize the radiological appearances on Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) - to understand the role and clinical importance of neuroimaging in patients with DAI Read more Background Diffuse axonal injury as the name implies is a traumatic stretch/disruption of axons that occurs with sudden acceleration/deceleration or rotation of the brain. Patients with DAI are most commonly injured in high-velocity vehicle crashes and DAI represents 50% of all primary intraaxial traumatic brain lesions in moderate/severe traumatic brain injury (TBI). It has 80-100% autopsy prevalence in fatal injuries and even occurs in utero if pregnant woman subjected to sufficient force. Typically, patients present with loss of consciousness at the time of accident and often... Read more Findings and procedure details Non enhanced CT is the first-choice neuroimaging tool in all emergency head trauma patients, but MRI is the modality of choice for assessing suspected diffuse axonal injury. It is a potentially difficult diagnosis to make on imaging alone. Some patients with relatively normal CT scans may have significant unexplained neurological deficit, in those cases DAI should be suggestive and confirmed with MRI. On CT the finding can be subtle or absent, but that does not categorically exclude the presence of axonal injury. Contrary to the... Read more Conclusion DAI as a diagnosis should be suggestive in TBI patients with clinical symptoms disproportionate to imaging findings. More than 30% of patients with negative CT have positive MR, so in general it is clinically developed based on clinical manifestations and MRI findings. Neuroimaging plays a significant role, by detecting the location and number of lesions, not only in diagnosis but also in determining the outcome of patients after DAI.