Computed tomography (CT scan): A scanner takes multiple X-rays, which a computer converts into detailed images of the brain and skull.

Magnetic resonance imaging (MRI scan): Using radio waves in a magnetic field, an MRI scanner creates highly detailed images of the brain and other parts of the head.

Angiography (brain angiogram): A special substance doctors call "a contrast agent" is injected into the veins, and travels into the brain. X-ray videos of the brain are taken, which can show problems in the brain's arteries.

Magnetic resonance angiography (MRA): A special MRI scan of the brain's arteries. An MRA scan may show a blood clot or another cause for stroke.

Lumbar puncture (spinal tap): A needle is inserted into the space around the spinal nerves, and fluid is removed for analysis. Lumbar puncture is often done if meningitis is suspected.

Electroencephalogram (EEG): Brain activity is monitored through electrodes placed on the skin on the head. EEG can help diagnose seizures, or other brain problems.

Neurocognitive testing: Tests of problem-solving ability, short-term memory, and other complex brain functions. Usually, neurocognitive testing is done through questionnaires.

Brain biopsy: In rare situations, a very small piece of the brain is needed to make the diagnosis of a brain condition. Brain biopsies are generally done only when the information is needed to provide proper treatment.