Doctors have a number of tests that they use to diagnose metastatic brain tumors. After a routine physical exam, doctors may use one or more of the following tests, depending on the patient:
- Neurological exams - to determine a patient’s:
- Balance and coordination
- Reasoning and memory skills
- Computed tomography (CT) - scans which may reveal tumors near the bone, swelling and bleeding
- Magnetic resonance imaging (MRI) - scans which are considered to be the best technology to diagnose brain tumors. An MRI creates a three-dimensional image of the tumor(s) and functional magnetic resonance imaging (fMRI) scans can assist the doctor in pinpointing the exact location of the functional center in the brain.
- Biopsy - used to determine the exact type of tumor present and whether it is malignant (cancerous). During a biopsy, a small amount of the cancerous tissue is taken and analyzed under a microscope. A biopsy can usually be done during surgery in which all or part of the brain tumor is removed. Tumors buried deep in the brain sometimes cannot be approached safely. In those cases, a biopsy procedure involves using three-dimensional needle technique in which special imaging equipment guides the placement of a needle to allow cells to be drawn into the needle.
- Lumbar puncture - used to test cerebral spinal fluid to look for cells related to the tumor
- Cerebral angiography - may be used to show a mass that may, or may not, be a tumor
- Diffusion tensor imaging (DTI) - used to document changes in the brain’s structure over a period of time and allows the physician to study the connections between different areas of the brain
Sometimes, after examining tumor tissue, the tumor is diagnosed as a metastatic brain tumor but the patient has no history of cancer.
At this time, additional tests including a chest X-ray, mammogram, scans of the chest, abdomen and pelvis may be used to determine the site of the original cancer, which the patient may not know exists.