How is a Brain Tumor Diagnosed?

The doctor does a complete physical exam with special attention to neurological examination. This includes checks for alertness, muscle strength, coordination, reflexes and response to pain. The doctor also examines the eyes for swelling caused by a tumor pressing on the nerve that connects the eye and the brain.

The doctor may request a CT (or CAT) scan or an MRI. A CT scan is a series of detailed pictures of the brain. The pictures are created by a computer linked to an X-ray machine. Sometimes dyes are injected into to help show differences in the tissue of the brain.

An MRI (magnetic resonance imaging) gives pictures using a powerful magnet linked to a computer. An MRI is helpful in diagnosing brain tumors because it can "see" through the bone of the skull to the tissue underneath. A dye may also be used to enhance the likelihood of detecting the tumor.

An MRS (magnetic resonance spectroscopic) is a non-invasive method that can be used with MRI to provide information about cellular activity and degree of malignancy.

A PET (positron emission tomography) scan is a computerized imaging procedure that can help find cancer cells in the body.

• Other possible tests: 
  Skull X-ray – can show changes in bone or calcium deposits which are sometimes present in brain tumors.
• Brain scan – reveals and records abnormal areas on special film. A small amount of radioactive material is injected into the vein. This dye is absorbed by the tumor and shows up on the film. The radiation leaves the body within six hours and is not dangerous.
• Angiogram or ateriogram – a series of X-rays after a dye is injected into an artery. These X-rays can show the tumor and blood vessels that lead to it.
• Myelogram – an X-ray of the spine. A special dye is injected into the cerebrospinal fluid in the spine, and the patient is tilted to allow the dye to mix with the fluid. This test may be done if a doctor suspects a tumor in the spinal cord.