Stanford Brain Tumor Center
Expert diagnosis supported by our advanced MRI imaging expertise

Diagnosis of Brain Tumors

Diagnosis of a brain tumor is based mostly on the types of cells involved and the tumor location. Successful treatment begins with the skills of the diagnostic team.

By coming to Stanford for your diagnosis, you can be confident that all of the right tests will be done quickly and with great expertise from years of experience and advanced training. Our brain tumor diagnosticians work around the clock to ensure that your treatment begins with the correct and accurate diagnosis, and that you understand it clearly.

Who is on your diagnostic team at the Stanford Brain Tumor Center?

The physicians and nurses at the Stanford Brain Tumor Center have been recruited from among the best in the world at each of their subspecialties. They include neurologists, neuro-oncologists, pathologists and neurosurgeons who each have years of specialized experience in the diagnosis of brain tumors.

How Is the Diagnosis Made?

Brain and spinal cord tumors in adults are usually found because of symptoms that patients report to their primary care doctor. These symptoms can range from headaches to vision or balance problems, from speech problems to nausea.  Symptoms may begin gradually and become worse over time, or they can happen suddenly, as with a seizure.

When a brain tumor is suspected, many different tests are used to confirm the diagnosis. Your community-based physician may order some of the tests themselves and based on the results, refer you to the Brain Tumor Center at Stanford.  Because many brain tumor symptoms are common to other medical conditions, it is essential that they be diagnosed by an expert.

We Begin by Listening

We want to understand your symptoms and how they are affecting your quality of life. During your initial consultation we will listen carefully and answer all your questions with compassion and expertise. We’ll work closely with you and your family to ensure the best care throughout the entire process of diagnosis, treatment and recovery.

Possible Symptoms of a Brain Tumor

Tumors often cause increased pressure within the brain. This can be due to swelling caused by the size of the tumor, or to blockages caused by the tumor’s location.  The rise in pressure within the brain, called intracranial pressure or ICP, often causes symptoms that the patient experiences as a change in their wellbeing. Those symptoms may include:

  • Morning headache or headache that goes away after vomiting
  • Frequent nausea and vomiting
  • Vision, hearing, and speech problems
  • Loss of balance and trouble walking
  • Weakness on one side of the body
  • Unusual sleepiness or change in activity level
  • Unusual changes in personality or behavior
  • Seizures

Possible Symptoms of a Spinal Tumor

  • Back pain or pain that spreads from the back towards the arms or legs
  • A change in bowel habits or trouble urinating
  • Weakness in the legs
  • Trouble walking

Understanding the Tests Used for Brain Tumor Diagnosis

PET/CT scan

Neuroimaging is a very important part of the group of tools that doctors use to make an accurate diagnosis of a brain tumor.

Neuroimaging tests allow physicians to see what is going on inside your brain. The tests use x-rays, strong magnets, or radioactive substances to create pictures of internal organs such as the brain and spinal cord. The pictures are then analyzed by doctors specializing in the diagnosis and treatment of brain tumors (neurosurgeons, neurologists, and neuroradiologists) to arrive at the correct, detailed diagnosis.

Magnetic resonance imaging (MRI) and computed tomography (CT) scans are two of the neuroimaging techniques used most often to examine brain tumors. When a tumor is present, MRI or CT scans will almost always show it and can often tell the doctors exactly where the tumor is in the brain. They can also help indicate its severity. Imaging tests are sometimes repeated after treatment to measure improvement.

Stanford is the first healthcare institution in Northern California to offer patients a powerful new diagnostic imaging system known as PET/CT.

The most up-to-date imaging machinery is needed for the most accurate diagnosis. These advanced machines are available to all of our patients being seen for brain tumor assessment. This is a field that is evolving rapidly and Stanford’s advanced imaging machines are among the most sophisticated available anywhere.

A Summary of Diagnostic Tools Used for Brain Tumor Diagnosis and Evaluation

The following tests and procedures are used to diagnose a brain or spinal tumor. After treatment for a tumor, some of the tests and procedures are repeated to find out how much tumor is left and how further treatment should proceed.

  • Physical exam and personal history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
  • Neurological exam: A series of questions and tests to check the brain, spinal cord, and nerve function. The exam checks a person’s mental status, coordination, and ability to walk normally and how well the muscles, senses, and reflexes work.
  • Visual field exam: An exam to check your field of vision (the total area in which you can see objects around you). This test measures both central vision (how much a person can see when looking straight ahead) and peripheral vision (how much a person can see in all other directions while staring straight ahead). Any loss of vision may be a sign of a tumor that has damaged or pressed on the parts of the brain that affect eyesight.
  • Gene testing: A laboratory test in which a sample of blood or tissue is tested for changes in a genetic material that has been linked with a certain type of brain tumor. Much of this important research is being done at our own Stanford University Medical Center. This test may also be done to diagnose one of the few inherited medical conditions that are associated with brain tumors.
  • CT scan (CAT scan): A neuroimaging procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography.
  • MRI (magnetic resonance imaging): A neuroimaging procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of the brain and spinal cord. A substance called gadolinium is injected into a vein to help the physicians see the image more clearly. The gadolinium collects around cancer cells so they show up brighter in the picture. Sometimes a procedure called magnetic resonance spectroscopy (MRS) is done during the MRI scan. An MRS is used to diagnose tumors based on their chemical make-up.
  • fMRI (functional MRI): During an fMRI, the patient is asked to perform certain activities to help the neurosurgeons map the functional areas of the brain before surgery takes place.
  • PET scan (positron emission tomography scan): A PET scan is a neuroimaging technique used to find malignant tumor cells. A small amount of radioactive glucose (a sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the brain. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
  • A lumbar puncture (also called a spinal tap) can be used to analyze the fluid in the spinal cord. This test is helpful for spinal tumor assessment and also for measuring whether certain cancers have spread to the brain.

Surgical Procedures for Diagnosing a Brain Tumor

When diagnosing a brain tumor, it is also important to be able to directly examine the tissues of the tumor. This is done by extracting some of the tumor cells in a procedure called a biopsy. The biopsy is sometimes carried out in advance of surgery using only a needle to extract the cells under local anaesthesia. But most often, the biopsy is done at the same time that the neurosurgeon operates to remove the tumor. 

Once the tumor cells are obtained for a biopsy, a neuropathologist can immediately examine them under an extremely powerful microscope to provide the medical team with a highly accurate description of the cells found in the tumor.

The more detailed and accurate a diagnosis you can receive, the more specialized the treatment can be, resulting in the most hopeful prognosis.

Helping You Understand Your Diagnosis

In addition to naming the type of tumor you have, the tumor will be explained according to its severity, location and impact on your quality of life. Brain tumors are often given a grade as well as a name, using the following grading system. The grade of a tumor is based on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread.

  • Grade I (low-grade) — The tumor grows slowly, has cells that look a lot like normal cells, and rarely spreads into nearby tissues. It may be possible to remove the entire tumor by neurosurgery.
  • Grade II — The tumor grows slowly, but may spread into nearby tissue and may recur (come back). Some tumors may become a higher-grade tumor over time.
  • Grade III — The tumor grows quickly, is likely to spread into nearby tissue, and the tumor cells look very different from normal cells.
  • Grade IV (high-grade) — The tumor grows and spreads very quickly and the cells do not look like normal cells. There may be areas of dead cells in the tumor. Grade IV brain tumors are harder to cure than lower-grade tumors.

Learn more about different kinds of brain tumors »

Stanford’s Multidisciplinary Brain Tumor Board – Where the Experts Share their Most Complex Cases

At the weekly Tumor Board meetings, the brain tumor physicians come together to discuss the diagnosis and treatment for their most complex cases. They share their insights and expertise in this interdisciplinary setting to ensure that the most appropriate, research driven diagnosis and treatment decisions are made for each of their patients.


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