Imaging tests that take pictures of your brain also help diagnose a tumor. Doctors use imaging tests to help diagnose and treat brain tumors. Imaging tests take pictures of the brain that enable your doctor to see structures and surrounding tissue. These pictures help your doctor determine the best treatment options for the tumor.

MRI to diagnose brain tumors

Magnetic resonance imaging (MRI) is a common imaging test doctors use to diagnose brain tumors. This test uses radio waves and magnets to create images of brain structures. A technologist or nurse may perform this scan by injecting contrast dye into your arm to illuminate the tumor’s location. Doctors use 2 main types of MRI to diagnose brain tumors:

• Functional MRI: These tests map brain activity by evaluating the structures of the brain and detecting changes in blood flow. Functional MRIs allow doctors to see how close the tumor is to areas of the brain that control functions such as speech and movement. This guidance helps them understand the tumor’s potential effect on the body.
• Perfusion MRI: Doctors use this test to identify parts of the brain with less blood flow, a potential sign of a tumor blocking the path.
• Tractography: Visualizes white matter tracts which carry electric signals and sensory information for the central nervous system. These images are uploaded to a neurosurgical navigation system in the operating room to guide the surgeon around critical pathways as the tumor is removed.

CT scan to diagnose brain tumors

Some people cannot have an MRI because the magnets interfere with implanted medical devices such as pacemakers and cochlear implants. Computed tomography (CT) scans combine multiple X-rays and provide doctors with another way to see structures in the brain.

Some people receive contrast dye before a CT scan so the test provides a better image. This dye may be injected in a vein or given as a pill. A technologist performs a CT scan, which typically lasts 10 to 30 minutes.

Tissue and fluid sampling to diagnose brain tumors

Doctors may also collect tissue from the tumor or fluid from the spine for diagnosis. Looking at cells under a microscope can help doctors identify factors such as the type of tumor present and how quickly it may spread.

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