Brain Tumors

Diagnosis

Brain tumor diagnosis usually begins with a physical exam by the neurologist, which includes checking vision, hearing, balance, coordination and reflexes. Depending on results, the physician may request one or more of the tests below. A biopsy is usually required to diagnose a brain tumor and confirm its type.

Diagnostic imaging services are provided by radiologists who specialize in imaging the brain and nervous system, ensuring that each examination is performed and interpreted to the highest standard of quality. Mayo has an international reputation for high-quality imaging and rapid results. In Mayo's efficient system, exams are interpreted almost immediately afterwards, and results are available in Mayo's electronic records system on the same day.

Magnetic Resonance Imaging (MRI) scan

Giant cell astrocytoma

Enlarge

MRI is more sensitive than CT scanning for confirming the presence of a brain tumor. MRI uses magnetic fields to generate images of the brain. Using powerful software, MRI scans outline the normal brain structures in great detail, as well as provides information about physiology and chemistry. Sometimes a special dye is injected into the bloodstream to make tumors more distinguishable from healthy tissue (MR angiography).

Other Brain Scans

PET scan of glioblastoma multiforme

Enlarge

Other tests, such as magnetic resonance spectroscopy (MRS), single-photon emission computed tomography (SPECT) or positron emission tomography (PET) scanning, help doctors gauge brain tumor activity and blood flow. These scans can be combined with MRIs to help physicians understand the effects of a tumor on brain activity and function. If a brain tumor is seen on a brain scan, especially multiple tumors, physicians may test for cancer elsewhere in the body.

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 is painless and generally takes less than 10 minutes. While MRI is often the preferred imaging tool, CT can be very helpful in certain types of tumors, especially ones close to or involving bone. CT is superior to MRI in viewing bone areas.

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.

X-rays of the Head and Skull

An X-ray of the head may show alterations in the skull bones that could indicate a tumor. However, an X-ray is far less sensitive than brain scans and is not used often.