What is a Magnetic Resonance Imaging (MRI) scan?
If your oncologist suspects a brain metastasis, you will be asked a series of questions about any mental, emotional or physical changes you’ve recently experienced. These questions can help determine if a brain metastasis is the likely cause and give doctors an idea of where the tumor might be located.
You will then undergo a physical exam and an imaging exam, most likely an MRI (magnetic resonance imaging). This exam is the most common way to locate and confirm the diagnosis of a brain metastasis.
If the MRI is inconclusive, doctors may order a biopsy, a procedure in which a piece of the suspected tumor is removed and then tested. Biopsies can be performed surgically (by exposing larger sections of the brain) or with a needle guided by specialized navigation equipment. The location of the growth may make a biopsy difficult, though, and your doctor may recommend no biopsy at all.
In some cases, your physician may find the metastatic disease incidentally. This could happen if you have an imaging exam for something else, and the scan reveals a brain metastasis. When a brain metastasis is found before you begin to notice symptoms, early treatment may be able to prevent the development of neurological symptoms.
Leptomeningeal disease (LMD) is diagnosed differently. In this type of metastases, cancer cells attach to the lining of the brain and spinal cord and float in the liquid surrounding these structures, called cerebrospinal fluid (CSF). Doctors test this fluid to check for LMD. This requires a lumbar puncture (also called a spinal tap). During this procedure, a needle is inserted into the lower back to remove a small amount of CSF from the spinal canal. This sample is then checked for cancer cells. The procedure may be repeated as many as three times to increase the odds of identifying tumor cells.