Diagnosis of Astrocytoma
Doctors use many tests to find or diagnose CNS tumors. They also conduct tests to see if the tumor has spread to other parts of the body from where it started. If this happens, it is called a transfer. For example, imaging tests can show whether the tumor has spread. The imaging test shows a picture of the inside of the body. The doctor can also run tests to determine which treatment is the most effective.
For most types of tumors, a biopsy is the only reliable way for doctors to find out if there is a tumor in a certain part of the body. In a biopsy, the doctor will take a small sample of tissue for analysis in the laboratory. If a biopsy is not possible, the doctor may recommend other tests that will aid in the diagnosis.
This section describes the options for diagnosing astrocytoma. Not all of the tests listed below are suitable for everyone. Your child’s doctor may consider the following factors when choosing a diagnostic test:
Suspicious tumor type
Your child’s signs and symptoms
Your child’s age and general health
First medical test results
In addition to During physical examinations, the following tests are available for the diagnosis of astrocytoma:
Computed tomography (CT or CAT). A CT scan uses x-rays taken from different angles to take pictures of the inside of the body. The computer combines these images into detailed 3D images that show any abnormalities or tumors. Computed tomography can be used to measure the size of the tumor. Sometimes a special dye called a contrast agent is used before the scan to provide better image detail. The dye can be injected into a patient’s vein or swallowed as a pill.
Magnetic resonance imaging (MRI). MRI uses magnetic fields instead of X-rays to generate detailed images of the body. MRI can be used to measure the size of tumors. Use contrast agent before scanning to create a clearer image. The dye can be injected into a patient’s vein or swallowed as a pill or liquid.
Biopsy. Other tests may indicate the presence of a tumor, but only a biopsy can make a definite diagnosis. For astrocytomas, a biopsy is performed to determine the type and grade of the tumor. It can also be used to identify certain molecular features that help doctors plan treatment (see below). During the biopsy, a doctor called a neurosurgeon will remove a small piece of tissue from the tumor. Neurosurgeons specialize in using surgery to treat tumors of the central nervous system. The pathologist then analyzes the sample. A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose diseases.
Molecular tumor test. Your child’s doctor may recommend laboratory tests of tumor samples to determine genes, proteins, and other factors specific to the tumor. The results of these tests can help determine your child’s treatment plan. After completing the diagnostic tests, your child’s doctor will review all the results with you. If an astrocytoma is diagnosed, these results can also help the doctor describe the tumor. This is called staging and classification.