Brain, Spine & Skull Base Cancers

There is an array of tests conducted to help diagnose brain and spinal tumors and to evaluate the effects of tumors on neurologic function:

• A neurological exam, consisting of a series of questions and tests to check the brain, spinal cord, and nerve function. The exam reveals the state of a person’s mental status, coordination, and ability to walk normally, as well as their muscles, senses, and reflexes.
• A visual exam that checks a person’s field of vision to measure 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.
• A tumor marker, which measures the amounts of substances made by organs, tissues, or tumor cells in the body that are linked to specific types of cancer.

• Gene testing to analyze cells or tissues and look for changes in genes or chromosomes, which may be a sign that a person has or is at risk of having a specific disease or condition.

  A CT scan to take a series of detailed pictures of areas inside the body at different angles. The pictures are made by a computer linked to an X-ray machine, and 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, computerized tomography, or computerized axial tomography.

• An MRI with gadolinium, which 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, which collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI). MRI is often used to diagnose tumors in the spinal cord. 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 makeup.
• A PET (positron emission tomography scan) to find malignant tumor cells in the body. A small amount of radioactive glucose (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. PET is used to tell the difference between a primary tumor and a tumor that has spread to the brain from somewhere else in the body.

If imaging tests show there may be a brain tumor, a biopsy is usually done. One of the following types of biopsies may be used:

• Stereotactic biopsy to reveal whether a tumor deep in the brain is in a hard-to-reach place. This kind of biopsy uses a computer and a three-dimensional (3-D) scanning device to find the tumor and guide the needle used to remove the tissue. A small incision is made in the scalp, and a small hole is drilled through the skull. A biopsy needle is inserted through the hole to remove cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer.
• Open biopsy. If imaging tests show that there may be a tumor that can be removed by surgery, an open biopsy may be done. A part of the skull is removed in an operation called a craniotomy and a sample of brain tissue is removed and viewed under a microscope by a pathologist. If cancer cells are found, some or all of the tumor may be removed during the same surgery. Tests are done before surgery to find the areas around the tumor that are important for normal brain function. There are also ways to test brain function during surgery. The doctor will use the results of these tests to remove as much of the tumor as possible with the least damage to normal tissue in the brain.