Exams and Tests
Findings of your medical interview and physical exam will probably suggest to your health care provider that you have a problem with the brain or brain stem.
In most cases, you will have a CT scan of the brain. This test is like an X-ray, but shows more detail in three dimensions. Usually, a contrast dye is injected into your bloodstream to highlight abnormalities on the scan.
More often, the MRI scan is being used instead of a CT scan for suspected brain tumors. This is because MRI has a higher sensitivity for detecting the presence of, or changes within, a tumor. However, most institutions still use the CT scan as the first diagnostic test.
People with brain cancer often have other medical problems; therefore, routine lab tests may be performed. These include analysis of blood, electrolytes, and liver function tests.
If your mental status has been the major change, blood or urine tests may be done to detect drug use.
If your scans indicate the presence of a brain tumor, you will be referred to a cancer specialist, called an oncologist. If one is available in your area, you should be referred to a specialist in brain tumors, called a neuro-oncologist.
The next step in diagnosis is confirmation that you have a cancer, usually by taking and testing a sample of the tumor. This is called a biopsy:
- The most widely used technique for obtaining a biopsy is surgery. The skull is opened, usually with the intention of removing the whole tumor, if possible. A biopsy is then taken from the tumor.
- If the surgeon is unable to remove the entire tumor, a small piece of the tumor is removed.
- In some cases, it is possible to collect a biopsy without opening the skull. The exact location of the tumor in the brain is determined by using a CT or MRI scan. A small hole is then made in the skull and a needle guided through the hole to the tumor. The needle collects the biopsy and is removed. This technique is called stereotaxis, or stereotactic biopsy.
- The biopsy is examined under a microscope by a pathologist (a doctor who specializes in diagnosing diseases by looking at cells and tissues).