Thunderclap Headache — Call 911 Immediately
A sudden, severe headache described as "the worst headache of your life" or a thunderclap headache may indicate a serious emergency. Stroke symptoms (face drooping, arm weakness, speech changes), loss of consciousness, or seizure also require immediate ER evaluation. Do not use DOD — call 911 or go to the nearest ER immediately.
CT Head Scan: What Patients Should Know
A CT head scan uses X-rays taken from multiple angles to create cross-sectional images of the brain, skull, and surrounding structures. CT is fast and widely available. It uses ionizing radiation. Provider orders are required at most facilities.
Educational content only. Clinical appropriateness determined by a licensed provider. DOD does not perform or interpret CT scans. Emergency symptoms require immediate ER evaluation.
Quick Answer
A CT head scan creates cross-sectional images of the brain, skull, sinuses, and related structures using X-ray technology. It is fast (minutes), widely available, and excellent at detecting bone abnormalities and intracranial hemorrhage. It involves ionizing radiation and may use IV contrast in some protocols. Provider orders are required at most facilities. For headaches, DOD can review non-emergency CT order requests. For thunderclap headache or stroke symptoms, call 911 immediately.
What CT Head Imaging Shows
Brain Parenchyma
Gray/white matter differentiation, general brain structure, larger areas of abnormal density
Intracranial Hemorrhage
Acute blood appears hyperdense (bright white) on CT — CT is the modality of choice for acute hemorrhage detection
Skull and Cranial Bones
Fractures, bone lesions, orbital walls, temporal bones
Ventricular System
Ventricle size and symmetry, hydrocephalus assessment
Sinuses
Paranasal sinuses — fluid, opacification, anatomical variants
Soft Tissue of Orbits and Skull Base
Orbital contents, extraocular muscles, skull base structures (limited compared to MRI)
Frequently Asked Questions — CT Head
Sources
- CT of the Head — Patient Information — RadiologyInfo.org (ACR / RSNA)
- CT Scans — MedlinePlus (NIH)
- CT and Radiation — FDA
Related Education and Order Pages
Need a Provider Review for a CT Head Order?
$40 virtual provider review. For emergency symptoms, call 911 — do not use DOD.
Start Virtual Consult — $40Not for emergencies. Orders not guaranteed.
Educational content only. DOD does not perform or interpret CT head scans. Emergency symptoms require immediate ER evaluation.