Diagnosis of Brain Tumors

To find the cause of a person's symptoms, the doctor asks about the patient's personal and family medical history and performs a complete physical examination. In addition to checking general signs of health, the doctor does a neurologic exam. This includes checks for alertness, muscle strength, coordination, reflexes, and response to pain. The doctor also
examines the eyes to look for swelling caused by a tumor pressing on the nerve that connects the eye and the brain.

Depending on the results of the physical and neurologic examinations, the doctor may request one or both of the following:

  • A CT (or CAT) scan is a series of detailed pictures of the brain. The pictures are created by a computer linked to an x-ray machine. In some cases, a special dye is injected into a vein before the scan. The dye helps to show differences in the tissues of the brain.
  • MRI (magnetic resonance imaging) gives pictures of the brain, using a powerful magnet linked to a computer. Unlike CT, MRI scans do not require any radiation. MRI is especially useful in diagnosing brain tumors because it can "see" through the bones of the skull to the tissue underneath. A special dye may be used to enhance the likelihood of detecting a brain tumor.

The doctor may also request other tests such as:

  • A skull x-ray can show changes in the bones of the skull caused by a tumor. It can also show calcium deposits, which are present in some types of brain tumors.
  • An angiogram, or arteriogram, is a series of x-rays taken after a special dye is injected into an artery (usually in the area where the abdomen joins the top of the leg). The dye, which flows through the blood vessels of the brain, can be seen on the x-rays. These x-rays can show the tumor and blood vessels that lead to it.
  • A myelogram is 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 when the doctor suspects a tumor in the spinal cord and is usually followed by a CT scan to assess the dye flow in 3D.