Diagnosis
Most brain tumors aren’t detected until the patient starts having symptoms. If a child has any symptoms of a brain tumor, the doctor will conduct a physical exam and take a complete medical history. The doctor may then use the following tests to diagnose the disease:
Physical Examination and 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 a patient's health habits and past illnesses and treatments will also be taken.
Neurologic Examination
The doctor will perform a neurologic exam to test a child's brain and spinal cord function. A neurologic exam tests vital functions such as vision, hearing, muscle strength, reflexes, coordination and alertness. If a child's tests results are irregular, the doctor may refer him or her to a neurologist for further testing.
Click Image to Enlarge.
Computed Tomography (CT) Scan
A computed tomography (CT) scan uses X-rays to produce an image of your body. A special dye may be injected into your veins and you may be asked to drink a special fluid in order to make the internal organs stand out. A CT scan produces detailed cross-sectional images of the brain, allowing doctors to pinpoint the exact location of the cancer in the brain. CT scans show bone, calcification, enlarged ventricles, bleeding and swelling well but do not give the best picture of the soft tissue of the brain and are not as good as MRIs in showing the characteristics of the tumor.
Click Image to Enlarge.
Magnetic Resonance Imaging (MRI) Scan
Magnetic resonance imaging (MRI) uses radio waves and a strong magnet to create clear and detailed images of body parts. Radio waves are absorbed by the body and then released in a certain pattern, which is translated by a computer in order to show "slices" of the body. This test is very useful for examining the soft tissues in the head. MRIs can show differences in brain tissue, allowing doctors to identify brain tumors.
Click Image to Enlarge.
Positron Emission Tomography (PET) Scan
For a PET scan, the doctor injects a radioactive substance into the patient's bloodstream. This substance collects in malignant (cancerous) cells in the patient's body. The doctor then uses a PET scanner to detect these areas of radioactivity and to find the exact location of cancer in the brain. This is often used to distinguish tumor recurrence from radiation induced changes in the tumor area.
Click Image to Enlarge.
Lumbar Puncture
A lumbar puncture procedure is done in order to collect cerebrospinal fluid from the spinal column. A needle is placed between two bones in the spine and into the cerebrospinal fluid surrounding the area. The sample is then studied under a microscope in order to determine if cancer is present. This procedure is also known as a spinal tap. It is highly recommended that patients have this procedure, especially if they have an aggressive HIV-related- B-cell lymphoma, since a lumbar puncture will allow for analysis of cerebrospinal fluid and check for possibility of leptomeningeal lymphoma (a severe situation where cancer spreads to membranes of spinal cord and brain).
Click Image to Enlarge.
Tumor Marker Tests
A procedure in which the sample of blood is examined to measure the amounts of certain substances released into the blood by organs, tissues, or tumor cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the blood. These are called tumor markers.
Blood Studies
Both blood chemistry and blood hormone studies are done in order to measure the amount of certain substances in the blood. A blood sample is taken from the patient and checked for either specific substances or hormones released by organs and tissues in the body. An unusual (higher-than normal or lower-than normal) amount of substance or hormone can be a sign of disease. Blood hormone studies check for unusual levels of thyroid-stimulating hormone (TSH) or hormones made by the pituitary gland in the brain.
Click Image to Enlarge.
Surgical Biopsy (Craniotomy)
During a craniotomy, the doctor removes the tumor. After removing the tumor, the doctor will send a tissue sample to the lab to verify the diagnosis. A biopsy is the only way to be certain that a brain tumor is malignant.
Click Image to Enlarge.
Stereotactic Biopsy
Doctors perform stereotactic biopsies for tumors that are deep in the brain and difficult to reach. The doctor drills a small hole in the patient's skull and uses a CT scan or MRI to guide a needle to the precise location of the tumor to draw a tissue sample. If the tumor is in the brain stem or another critical area, it may not be possible to extract a tissue sample without harming healthy tissue.
Click Image to Enlarge.
Bone Marrow Aspiration & Biopsy
In this test, the doctor uses a thin needle to extract a sample of tissue from the hip bone, and has it sent to a lab to be examined under a microscope. This procedure is not often used to diagnose childhood brain tumors, but can help determine if the cancer has spread to the bone marrow.
