Pediatric Brain Tumors

Diagnosis

Brain tumor diagnosis usually begins with a neurological exam by the neurologist, which includes checking vision, hearing, balance, coordination and reflexes. Depending on those results, the physician may request one or more tests described below. A child may need general anesthesia for some tests to be successful.

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 after the exam, and results are available in Mayo's electronic records system on the same day.

Computed 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. The child lies on a movable table that is guided into what looks like an enormous doughnut where the images are taken. A special dye may be injected into the bloodstream after a few CT scans are taken. The dye increases the tumors visibility on X-ray. A CT scan is painless and generally takes less than 10 minutes.

Magnetic Resonance Imaging (MRI) Scan

This scan uses magnetic fields and radio waves to generate images of the brain. The child lies inside a cylindrical machine for approximately one hour. MRI scans are particularly useful in diagnosing brain tumors because they outline the normal brain structures in great detail. Sometimes a special dye is injected into the bloodstream during the procedure. The dye sometimes can help distinguish tumors from healthy tissue.

Other Brain Scans

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

Biopsy

Once a brain tumor is detected by an MRI or CT scan, a biopsy is usually required to determine the tumor type and grade. A biopsy involves removing a piece of the tumor for viewing under a microscope. The physician needs to know the type and grade of tumor in order to plan the proper treatment.

A biopsy can be performed as part of surgery to remove a brain tumor, or separately.

At Mayo, the tissue is examined by a neuropathologist who specializes in examining brain and nervous system tumors. This is critical for reaching an accurate diagnosis. Studies have shown that the diagnosis may change substantially for at least one-third of patients when pathological review is performed by an experienced neuropathologist. Mayo's neuropathologists are internationally known for their expertise in diagnosing brain tumors.

Read more about brain tumor biopsies on the brain tumor pages.