Brain Tumor Diagnosis - MRI

If your physician suspects that you have a brain tumor, he or she may recommend several tests and procedures to confirm your diagnosis. Usually, the diagnostic process begins with a magnetic resonance imaging (MRI) scan. This test can help your physician identify the presence of a brain tumor and evaluate its location, size and other characteristics, which are important considerations when planning treatment.

Unlike an X-ray, which uses radiation waves, an MRI uses strong magnetic fields, radio waves and a computer to produce a series of detailed images of the body’s internal structures, such as the brain and spinal cord. For heightened image clarity, a special dye known as a contrast medium may be given intravenously during an MRI.

Types of MRIs

Different types of MRIs can be used for a brain tumor diagnosis. Depending on the results of a neurological examination, a physician may order:

• An intravenous (IV) gadolinium-enhanced MRI – Following a standard MRI, a special contrast medium known as gadolinium is administered through an IV. The gadolinium collects around cancerous cells, making them show up brighter in images. A second MRI is then performed to obtain a set of images enhanced by the dye for comparison.
• Diffusion-weighted imaging – This MRI technique provides information about white matter tracts, which are signaling pathways in the brain, to help the physician evaluate the cellularity, nature and structure of a brain tumor. This technique can also provide information about a stroke.
• Perfusion imaging – This MRI technique provides information about the microscopic blood vessels that are supplying a tumor.
• A functional MRI (fMRI) – During an fMRI examination, the patient is asked to complete certain tasks while lying still, such as thinking about specific topics or performing silent brain exercises. These tasks cause tiny blood flow changes in the active part of the brain, which can be seen on an fMRI image. Often used for diagnostic purposes as well as to plan surgery, this test provides information about the location of specific areas of the brain that are responsible for critical functions, such as speech and muscle movement.
• Magnetic resonance spectroscopy (MRS) – This test provides information about the chemical composition of the brain, helping the physician identify cancerous cells and measure the progression of a tumor.

Medically Reviewed by Dr. Michael Vogelbaum, Program Leader, Department of Neuro-Oncology.

If you would like to learn more about how an MRI scan can be used to diagnose a brain tumor, you can request a consultation with a specialist in the Neuro-Oncology Program at Moffitt Cancer Center. To do so, call 1-888-663-3488 or complete a new patient registration form online.