Head CT for headache

Head CT is a test that is often done to investigate the cause of headaches.  It is a quick and readily available test that can show many conditions of the brain which can cause headache.
A head CT is a painless test done in a CT scanner that takes pictures of your brain and skull in cross sections. A specially trained radiology doctor will interpret the images.

What kinds of symptoms indicate a headache may be serious?

There are some worrisome symptoms such as worst headache of your life.   Loss of strength or inability to walk without losing balance.  Altered mental status such as confusion or drowsiness.  Fever and neck stiffness may indicate meningitis.

How does your doctor get to the cause of a headache?

Your doctor will take a detailed history, do a physician exam and order imaging tests like head CT, MRI and angiograms of the brain.  An angiogram of the brain is a test done to look at the blood vessels.  This can be done with CT or MRI.

A brain MRI is needed at times to investigate the cause of a headache. A brain MRI is more detailed and shows structures in the brain to greater detail.

A specialty trained neurologist can be consulted to guide further diagnosis and treatment.

What does a head CT rule out?

Head CT rules out things quickly which need urgent treatment like a brain bleed, a mass, or stroke.

What can a CT scan show for headaches?


Often head CTs done for headaches are normal.  This is reassuring but does not mean everything is normal.  Head CTs do not show many causes of headaches.


Infection of the sinuses around your nose.

Bleeds- subdural

Head CTs are good for detecting bleeds.  A common type of bleed is called a subdural.  These occur in the space between the skull and brain.  These bleeds can push on the brain.

Often these are due to trauma. This trauma can be minor in the elderly or those on blood thinners. Occasionally subdural bleeds can go unnoticed and cause symptoms of dementia.  A neurosurgeon may be needed to evacuate the bleed.

Bleeds- subarachnoid

Another type of bleed in the brain can be due to subarachnoid hemorrhage.   This can occur when an aneurysm ruptures, there is trauma, high blood pressure or an underlying lesion of the brain.


Tumors can also cause headaches and be detected on head CT.  Masses can push on the brain and shift structures.


Strokes will have a typical clinical presentation such as weakness, difficulty speaking or numbness. A head ct may not show a stroke when it is early.

Normal ct scan but still have headaches?

A negative head ct will give your doctor reassurance that many serious conditions that require prompt treatment are not present. Some serious conditions will however not show on a head ct done for headache.

For example, meningitis and aneurysm will not be identified. Meningitis will often require a spinal tap to diagnose. An aneurysm will require a special CT called an angiogram of the blood vessels.  Infections of the brain may not be detected on a head CT.

Many lifestyle factors can cause headaches like: stress, lack of sleep and alcohol use.

Therefore, a head CT is just a quick start and by no means the end of a work up for headache.

Can a head CT show migraines?

Migraines usually have no findings on head CT.  This is a clinical diagnosis.

Is a CT scan or MRI better for headaches?

Often a head CT is ordered to rule out conditions which may need immediate treatment. The test is fast and easy since it can be done at any time in most emergency rooms and hospitals. It’s not as detailed as an MRI, but this test is longer and hard to get at all times.  An MRI can provide more detail of the brain and can diagnose more conditions.

Head CT for headache with and without contrast

Giving contrast through a vein allows more abnormalities to be seen.  Conditions like tumors, infections, and inflammatory conditions can sometimes be detected when IV contrast is given.

Head CT for headache: summary

Head CTs are often done for headaches because they can identify many serious conditions.  Head CTs are available at all times in most hospitals and are often the first imaging test done for headache.  We can identify many conditions which require prompt treatment like bleeds, tumors and strokes.

Disclaimer: The content of this website is provided for general informational purposes only and is not intended as, nor should it be considered a substitute for, professional medical advice. Do not use the information on this website for diagnosing or treating any medical or health condition. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider.

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