Glioma

Diagnosis

Diagnosing a glioma usually begins with a medical history review and exam by a brain disorder specialist (neurologist), which includes checking your vision, hearing, balance, coordination and reflexes. Depending on those results, your doctor may request one or more of the tests described below. At Mayo Clinic, all of your diagnostic testing can be completed in a few days rather than in several weeks or months.

Imaging tests

Mayo Clinic has an international reputation for high-quality imaging and rapid test results. Radiologists who specialize in imaging the brain and nervous system perform and interpret each examination to the highest standard of quality.

Imaging scans help gauge the tumor's effect on your brain activity and function, and blood flow. If a brain scan detects a tumor, especially multiple tumors, your doctor may test for cancer elsewhere in your body. Imaging tests may include:

• Magnetic resonance imaging (MRI) scan. MRI uses a magnetic field and radio waves to create detailed images of the brain. Sometimes a special dye is injected into the bloodstream to make tumors appear different from healthy tissue (MR angiography). Perfusion, functional and intraoperative MRI scans may be done to identify blood flow and volume, critical brain areas involved in speech and motor activity, and the tumor's precise location.
• Computerized tomography (CT) scan. A CT scan uses a sophisticated X-ray machine linked to a computer to produce detailed, two-dimensional images of the brain. A CT scan can help identify certain types of tumors, especially those close to or involving bone.
• Other brain scans. Other tests — such as magnetic resonance spectroscopy (MRS), single-photon emission computerized tomography (SPECT) or positron emission tomography (PET) scanning — help doctors gauge brain tumor activity and blood flow.
• Angiogram. A special dye is injected into the arteries that feed the brain, making the blood vessels visible on X-ray. This test helps locate blood vessels in and around a brain tumor.

Biopsy

Your surgeon will typically do a biopsy to diagnose a brain tumor and confirm its type. A biopsy involves removing a tiny piece of tumor tissue for examination under a microscope as part of the surgery to remove the tumor.

The sample is examined instantly by a specialist in assessing brain tissue tumors (neuropathologist) to identify the kind of tumor, which is critical in determining the appropriate treatment for you. Mayo Clinic's neuropathologists are internationally known for their expertise. Studies show that the diagnosis may change substantially for at least one-fourth of people when an experienced neuropathologist does the analysis.

Read more about the MRI scan and CT scan at MayoClinic.com.

Read more about brain tumor diagnosis at MayoClinic.com.