Symptoms and Diagnosis
The symptoms of a brain tumor vary and often are similar to those of other neurological conditions. Neurological examinations, imaging studies, laboratory tests, and pathology reports are all tools physicians use to determine whether a brain tumor is present, and if there is one, its specific type.
Headache, even when severe, is not necessarily symptomatic of a brain tumor. However, headache that is accompanied by loss of balance; nausea and vomiting; double vision; or numbness may indicate the presence of a brain tumor. Also of concern is the steady headache that is worse in the morning than in the afternoon.
Some people with brain tumors experience seizures, hearing or vision loss, reduced movement in the limbs, and speech difficulty. Sometimes a stroke can be due to a brain tumor. Women of child-bearing age may find that their monthly periods have stopped, although they are not pregnant. Significantly, not all of the symptoms of a brain tumor are physical; they can also include a change in behavior, memory loss, and an inability to concentrate or reason.
Because these symptoms are shared with many conditions other than brain tumor, it's imperative that medical care be sought for an accurate diagnosis. A neurological exam typically assesses a patient's vision and eye movement; reflexes; coordination and balance; sensory abilities, such as smell and touch; and mental aptitudes for memory and abstract thinking.
Following the exam, the doctor may order other tests, such as:
- Computed Tomography (CT): By using this combination of a sophisticated X-ray device and a computer, the brain's structure and tissues can be imaged. A contrast material-iodine dye-may be injected into the patient during the scan, making it easier to detect the tumor's location and other abnormalities.
The Brain Tumor Program at University Hospital uses a state-of-the-art scanner, the General Electric LightSpeed®; QX/i, to produce images with unprecedented speed and image clarity. The LightSpeed can capture multiple images about six times faster than traditional scanners. The state-of-the-art scanner also gathers 16 times more anatomical information in a single scan than other CT units and produces sharp, detailed images.
- Magnetic Resonance Imaging (MRI): This equipment uses a magnetic field rather than radiation to capture an image. By scanning at different angles, it can provide a 3-dimensional image of the brain. Contrast material is also often used. There are different types of MRI techniques:
Intraoperative MRI utilizes images obtained during surgery. These images provide the surgical team with a navigation route that adjusts for brain shift during the procedure. Furthermore, it provides the surgeon with the opportunity to safely expand the operative area if necessary for maximum lesion removal.
Functional MRI (fMRI) is used for pre-operative brain mapping and surgical planning to assist the surgeon in avoiding vital areas of the brain. Patients perform various functions while the MRI is scanning, so that the patient-specific functional areas of the brain can be clearly identified on the image.
A flow-sensitive MRI can show how cerebral spinal fluid (CSF)is traveling through ventricles-small cavities in the brain that hold CSF-and the spinal cord. This technique combines images of CSF flow with functional MRI.
MRI techniques cannot be used with patients who have pacemakers or other devices that could be affected by the magnetic fields.
- SPECT: Single Photon Emission Computed Tomography, or SPECT, is a scanner that measures a low-dose radioactive material as it circulates through the brain. SPECT can be used to differentiate between low and high grade tumors.
For some patients, other tests may be ordered: X-rays of the skull may be used to show if any bony erosion or calcification are occurring; cerebral angiographytakes X-rays of the brain's blood vessels and may show the tumor's position; and an electroencephalogram (EEG) records electrical activity in the brain.
Laboratory tests can provide useful information in the diagnosis of brain tumors. A lumbar puncture, or spinal tap, draws out cerebral spinal fluid. The fluid is examined for tumor cells, markers, infection, or blood. A blood sample can be assessed for hormone levels, which may be affected by the presence of a pituitary tumor.
Ultimately, a biopsy can provide a specific diagnosis. When stereotactic equipment is used for biopsy, a computer guides the needle to the precise tumor site. A small sample of the tumor is taken and sent to a pathologist for examination.