From the Guidelines
To rule out other causes of post-traumatic headache after a motor vehicle accident, a noncontrast head CT is usually the first-line imaging study recommended, especially in the acute setting. This non-invasive test can quickly identify serious conditions like intracranial hemorrhage, skull fractures, or brain contusions that may require immediate intervention 1. The American College of Radiology (ACR) Appropriateness Criteria recommend noncontrast head CT for the initial imaging of patients with acute head trauma that is mild (GCS 13–15) when imaging is indicated by clinical decision rule, and for patients with acute head trauma that is moderate (GCS 9–12) or severe (GCS 3–8) or penetrating 1.
If the CT scan is negative but symptoms persist or worsen, an MRI of the brain may be indicated as a second-line study, as it provides superior soft tissue detail and can detect subtle abnormalities not visible on CT, such as small contusions, diffuse axonal injury, or small subdural hematomas 1. MRI is more sensitive than CT for subtle findings adjacent to the calvarium or skull base and for small white matter lesions in traumatic axonal injury or DAI 1.
In some cases, additional imaging studies may be warranted, including MR angiography (MRA) or CT angiography (CTA) to evaluate for vascular injuries like dissections or aneurysms if there are concerning neurological symptoms 1. Cervical spine imaging, typically starting with X-rays and potentially progressing to CT or MRI, may also be appropriate since neck injuries often accompany head trauma in MVAs and can contribute to post-traumatic headaches.
Key considerations for imaging studies in post-traumatic headache include:
- Noncontrast head CT as the first-line imaging study in the acute setting
- MRI as a second-line study for persistent or worsening symptoms
- Additional imaging studies (MRA, CTA, cervical spine imaging) as needed based on clinical presentation
- ACR Appropriateness Criteria recommendations for imaging in acute head trauma 1
From the Research
Imaging Studies for Post-Traumatic Headache
To rule out other causes of post-traumatic (post-concussive) headache after a Motor Vehicle Accident (MVA), several imaging studies can be considered:
- Computed Tomography (CT) scan: A CT scan is often the first imaging study performed in the emergency setting to rule out acute bleeding or other serious conditions such as subarachnoid hemorrhage (SAH) 2, 3.
- Lumbar Puncture (LP): If the CT scan is negative, a lumbar puncture may be performed to check for blood in the cerebrospinal fluid, which can indicate SAH 2, 3.
- Magnetic Resonance Imaging (MRI): MRI can be used to evaluate for other causes of headache, such as subdural hematoma or cervical spine injury 4.
- Functional imaging techniques: Techniques such as proton spectroscopy magnetic resonance imaging, diffusion tensor imaging, and magnetic resonance morphometry may be used in research settings to better understand the pathophysiology of post-traumatic headache 5.
Considerations for Imaging
When deciding which imaging studies to perform, clinical acumen is required to determine if imaging is needed to assess for a secondary cause of headache 5.
- Clinical symptoms: The presence of focal neurological deficits, worsening headache, or other concerning symptoms may prompt further imaging evaluation 4.
- Timing: The timing of imaging studies may also be important, as some conditions such as SAH may not be immediately apparent on initial imaging 2.
Limitations and Potential Complications
It is essential to weigh the potential benefits of imaging studies against the risks and limitations:
- False positives: Lumbar puncture can result in false positive results, leading to unnecessary further evaluation and treatment 3.
- Complications: Imaging studies, particularly lumbar puncture, can be associated with complications such as infection, bleeding, or nerve damage 3.
- Limited diagnostic yield: In some cases, imaging studies may not identify a specific cause of post-traumatic headache, highlighting the need for careful clinical evaluation and consideration of other potential causes 5, 3.