A negative CT or MRI may not rule out the occurrence of a traumatic brain injury
A negative or normal computed tomography (CT) or magnetic resonance imaging (MRI) does not rule out a traumatic brain injury. Imaging can be negative or considered normal for mild, moderate, or even severe TBIs, but would be atypical for a severe TBI to be normal.
There are several reasons why imaging of the brain may appear to be “normal” or negative for injury but a TBI may still have occurred.
Sensitivity of Imaging. The choice of imaging performed may not be sensitive enough to identify brain injury.
A CT scan is good at detecting life-threatening bleeds and skull fractures but is not as sensitive as MRIs at detecting microscopic injuries like microbleeds and widespread injury to the axons and nerve fibers known as diffuse axonal injury that are typical of concussion and mild TBI. An MRI can capture images or slices as fine as 1 mm thick while CT images are about 3-5mm thick. With a thicker slice the CT is more likely to skip over trauma buried between the image slices. Not all MRIs are created equal and some or more sensitive than others and are designed to detect different brain functions.
Timing. The timing of imaging can also be a factor. A bleed like a subarachnoid hemorrhage is transient and optimally evaluated immediately with CT while delays of a few hours or days could result in missing the window to identify the subarachnoid hemorrhage by CT. Imaging performed early during the acute phase is not likely to show brain atrophy from trauma that may appear later as more time passes.
Understanding these differences about imaging and how imaging plays a role in diagnosing and proving traumatic brain injury is vital to protecting the legal rights of brain injury victims and our clients. We are committed to working with expert radiologists and neuroradiologists and staying knowledgeable about the latest in brain imaging science to protect our client’s rights.
If you have any questions or would like to learn more about our legal services and how our focus in brain injury and bicycle injury cases matters, please get in touch with us via our contact page at Contact Us.
If you found this post helpful, you might also like to explore the other topics listed below and the many other topics in our comprehensive Safety & Prevention Guide, Brain Injury Guide, and Bike Injury Guide.
