Diagnosis

Brain imaging

Your doctor will likely recommend brain imaging.

• Magnetic resonance imaging (MRI). An MRI of the brain can help detect any underlying causes for your headache. During the MRI exam, a magnetic field and radio waves are used to create cross-sectional images of the structures within your brain.

• Computerized tomography (CT). In some cases, especially if your headache occurred less than 48 to 72 hours beforehand, a CT scan of your brain may be done.

  CT uses an X-ray unit that rotates around your body and a computer to create cross-sectional images of your brain and head.

• Magnetic resonance angiography (MRA) and computerized tomography (CT) angiography. These tests visualize the blood vessels leading to and inside your brain and neck.

Angiograms

Your doctor may also order a cerebral angiogram, a test that can show the neck and brain arteries.

This procedure involves threading a thin, flexible tube through a blood vessel, usually starting in the groin, to an artery in your neck. Contrast material is injected into the tube to allow an X-ray machine to create an image of the arteries in your neck and brain.

Spinal tap

Sometimes a spinal tap (lumbar puncture) is needed as well — especially if the headache started abruptly and very recently and brain imaging is normal.

With this procedure, the doctor removes a small amount of the fluid that surrounds your brain and spinal cord. The fluid sample can show if there's bleeding or infection.