Can a CT Scan Detect a Concussion? What It Can—and Can’t—Tell You

Advanced Imaging in Concussion Research

While standard CT scans remain limited in detecting concussions, advanced imaging methods are offering deeper insights into how the brain is affected after injury. One of the most studied tools in concussion research is diffusion tensor imaging (DTI)—a type of MRI that maps the brain’s white matter tracts. DTI can detect subtle disruptions in axonal integrity, which are often present after mild traumatic brain injury but invisible on traditional scans.

Research using DTI has shown measurable changes in brain connectivity and microstructural integrity in individuals with concussion-related symptoms. Studies have also explored techniques like functional MRI (fMRI), susceptibility-weighted imaging (SWI), and magnetic resonance spectroscopy (MRS) to evaluate changes in brain activity, blood flow, and metabolic function after head trauma.

These tools are helping researchers better understand the physiological effects of concussion. However, they are not currently part of routine clinical care due to cost, availability, and variability in interpretation. For now, these modalities remain valuable in research settings—and they continue to shape the future of how we understand and eventually diagnose concussion-related brain changes.

Clinical Application: When Is a CT Scan Warranted?

For healthcare professionals, the decision to order a CT scan after head trauma should follow established clinical decision rules, such as the Canadian CT Head Rule or the New Orleans Criteria. These tools guide practitioners in determining whether the patient’s presentation warrants imaging.

Typical indicators include:

• Prolonged loss of consciousness
• Seizure activity
• Signs of skull fracture (e.g., raccoon eyes, Battle’s sign)
• Persistent vomiting
• Focal neurological deficits
• Age over 65 or suspected coagulopathy

A patient with isolated symptoms such as headache, dizziness, and confusion—but no high-risk features—may not require a CT scan, especially in sports medicine or outpatient settings. As outlined in Medscape’s concussion workup guidelines, abnormalities are relatively rare in these populations (approximately 9–13%) and do not alter management in most cases (source).

What a “Normal” CT Scan Can—and Can’t—Tell You

For patients, families, and sometimes even coaches, a normal CT scan can lead to misconceptions. A clean scan does not mean the brain is uninjured. It simply means there is no evidence of structural damage—like bleeding or fractures—at a level detectable by the scanner.

This distinction matters. In persistent concussion symptom cases, where patients experience ongoing headaches, dizziness, or cognitive issues weeks or months after injury, CT scans often remain normal. Yet these individuals are experiencing very real symptoms driven by functional and physiological disruptions, which CT technology is not designed to detect.

An article from Cognitive FX emphasizes that standard imaging cannot detect functional brain changes, unlike advanced techniques such as functional MRI (fNCI), SPECT, or PET scans, which have shown greater promise in identifying altered brain activity in concussion patients (source).

Real-World Scenario: CT Use in Sideline and Clinical Decisions

Consider an athletic trainer working a Friday night football game. A running back takes a helmet-to-helmet hit and walks to the sideline with dizziness and confusion. He has no red-flag symptoms and recovers orientation within a few minutes. In this scenario, clinical assessment tools like SCAT6 and balance testing are appropriate. A CT scan is not indicated unless his symptoms escalate.

Now consider a different case: a basketball player falls, strikes her head, and loses consciousness for 45 seconds before vomiting. She’s slow to respond and demonstrates right-side weakness. This athlete should be referred to the ED for immediate CT imaging—not to assess for concussion, but to rule out a life-threatening intracranial injury.

These examples underscore that CT use is driven by clinical presentation and risk—not by a desire to “confirm” a concussion diagnosis.

What This Means for Athlete Care

CT scans serve a vital role in acute injury evaluation, especially when serious intracranial injuries are a concern. However, in typical concussion cases—especially in youth and sports-related settings—they provide little value in isolation. The absence of imaging findings does not mean the brain is functioning normally.

Understanding this allows healthcare professionals to educate athletes, families, and coaches more effectively, ensuring expectations align with current science. It also reinforces the importance of multidisciplinary care—from athletic trainers performing sideline evaluations to physical therapists guiding vestibular rehab and physicians coordinating long-term management.