Doctors use a variety of tests to detect and diagnose brain tumors. These tests can also show what type of brain tumor it is and if it has spread to other parts of the body. Your doctor may also run certain tests to determine the most effective course of treatment.
Brain Tumor Imaging Tests
Imaging tests are the primary method for detecting and diagnosing a brain tumor. They can also show if the tumor is a primary brain tumor or if it is cancer that has spread to the brain from another location within the body. Imaging diagnostic tests typically include:
- Magnetic Resonance Imaging (MRI), a test that uses magnetic fields to produce detailed images of the body
- Computed Tomography (CT) scan, which creates a 3-D picture of the inside of the body using X-rays taken from different angles
- Positron Emission Tomography (PET) or PET-CT scan, a test that creates pictures of organs and tissues using various substances, such as sugars or proteins
- Cerebral arteriogram, which is an X-ray (or series of X-rays) of the head that shows the arteries in the brain
Other diagnostic tests your doctor may perform to determine if a brain tumor is present can include:
- Lumbar puncture or spinal tap, which looks for tumor cells, blood, or tumor markers in the cerebrospinal fluid (CSF)
- Myelogram, a test used to find out if the tumor has spread to the spinal fluid, other parts of the brain, or the spinal cord
- Molecular testing of the tumor, which is used to identify specific genes, proteins, and other factors like tumor markers, that are unique to the tumor
- Neurological, vision, and hearing tests to see if a tumor is affecting brain functions
- Neurocognitive assessment, which is a detailed assessment of all major brain functions, including storage and retrieval of memory, language abilities, dexterity, calculation, and the patient's overall well-being
- Electroencephalography (EEG), a noninvasive test in which electrodes are attached to the outside of the patient’s head to measure the electrical activity of the brain
- Evoked potentials, which use electrodes to measure the electrical activity of important nerves that could be affected by a growing tumor
Various factors, including the type of brain tumor suspected, signs and symptoms, your age, current medical condition, and previous test results, are all considered when choosing a diagnostic test.
If imaging tests show there may be a brain tumor, the next step would be to perform a biopsy, which is taking a sample of the possible tumor. The sample of tissue will then be tested in a laboratory.
In most cases, brain tumors are not diagnosed until after the patient is experiencing symptoms. An internist or neurologist typically gives the initial diagnosis.