Brain Injury·December 18, 2025·1 min read

A Negative CT or MRI May Not Rule Out a Traumatic Brain Injury

Imaging sensitivity, slice thickness, and timing all matter. A 'normal' scan does not mean no TBI occurred, particularly for mild TBI and concussion.

By Attorney Dan D'Angelo

Trial Lawyer · Brain Injury Advocate · Avid Cyclist

Cyclist in Redcliff, Colorado stopped on the side of the road next to a yellow road narrows sign with mountains and yellow fall leaves in the background

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. The thicker slice of the CT is more likely than an MRI to skip over trauma buried between the image slices.

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.

Frequently Asked Questions

Can you have a brain injury with a normal CT scan?

Yes. CT scans can look normal in mild, moderate, and even some severe TBIs. They're built to catch life-threatening bleeds and skull fractures — not the cellular injuries and metabolic changes at the microscopic level typical of TBI. They are also only a snapshot at that moment in time. They won't always show what happened in the past or what may develop down the road with secondary injury caused by TBI.

Why is an MRI better than a CT at detecting concussion damage?

Sensitivity. Depending on the MRI, imaging slices can be as fine as 1mm thick versus 3–5mm for CT, so CT is more likely to skip over trauma buried between slices. MRI also detects microbleeds, diffuse axonal injury, and metabolic changes that CT simply can't see.

Does the timing of my brain scan matter?

Yes. Some injuries are transient — a subarachnoid hemorrhage is best caught on CT immediately, and a delay of hours or days can miss the window. Conversely, a scan done in the acute phase won't show brain atrophy that only appears with time.

Will a normal scan hurt my injury claim?

Insurance companies love to point at a "normal" scan and argue you're fine. But normal imaging doesn't rule out a TBI — it often just means the wrong test, or the right test at the wrong time. Knowing the difference is critical, and it's exactly what we do. If your scan was normal but your symptoms aren't, call me.

Have a question about your case?

Attorney Dan D'Angelo offers free consultations for brain injury and cycling accident victims throughout Colorado.

Free Consultation 303.831.1116

About the Author

Attorney Dan D'Angelo