Computer Axial Tomography (CT Scan)
Computed Axial Tomography, also known as a CT scan, uses computers to generate a three-dimensional image from flat, two-dimensional x-ray pictures. The patient lies on a table and is centered into the CT machine that is open on both ends and looks like a large mechanical donut. Neurological CT scans are used to view the brain and spine. They can detect bone and vascular irregularities, certain brain tumors and cysts, herniated discs, epilepsy, encephalitis, spinal stenosis (narrowing of the spinal canal), a blood clot or intracranial bleeding in patients with stroke, brain damage from head injury, and other disorders. Many neurological disorders share certain characteristics and a CT scan can aid in proper diagnosis by differentiating the area of the brain affected by the disorder.
Scanning takes about ten minutes (a CT of the brain or head may take slightly longer) on an outpatient basis.
Magnetic resonance imaging, also known as MRI, uses radio waves and a strong magnetic field instead of x-rays to provide clear, detailed pictures of internal organs and tissues. The patient lies on a bed that goes into the magnet, and the magnet and radio waves send information into a computer. The computer processes the information and then produces an image. MRI helps physicians to diagnose brain tumors or eye and inner ear problems. The test is painless, however, patients who are claustrophobic may find it somewhat uncomfortable. Due to the incredibly strong magnetic field generated by an MRI, patients are screened prior to going into the magnet.
Disease is a biological process, beginning long before we are aware of it. Mobile Positron Emission Tomography (PET), allows doctors to view the organ systems of our body and how they are functioning. Physicians can see how the body's cells are functioning and the exact location of a disease. PET is an imaging procedure that tells information not available through CT, MRI, X-ray, blood test or physical examination. PET is an invaluable clinical test for cancer, heart disease and neurological disorders, and is used more and more to diagnose patients with these serious conditions.
In neurology, PET is able to detect early signs of Alzheimer's, Parkinson's and Huntington's diseases, epilepsy and other disorders, even before some symptoms occur, making a critical difference in their treatment and management. PET scans can detect the onset of Alzheimer's disease two to three years before any other diagnosis can be made, and in the case of hereditary Alzheimer's, PET can detect the disease before symptoms occur.
PET is a safe and painless procedure, which typically takes about one or two hours to complete. Patients are injected with a small amount of non-dangerous radioactive sugar, and then rest for about an hour to wait for the body to process the sugar. In the mobile PET scanning room, the patient lies on a table that slowly passes through the scanner.
Electromyography, or EMG, is used to diagnose nerve and muscle dysfunction and spinal cord disease. It records the electrical activity from the brain and/or spinal cord to a peripheral nerve root (found in the arms and legs) that controls muscles during contraction and at rest.
During an EMG, very fine wire electrodes are inserted into a muscle to assess changes in electrical voltage that occur during movement and when the muscle is at rest. The electrodes are attached through a series of wires to a recording instrument. Testing usually takes place at a testing facility and lasts about an hour but may take longer, depending on the number of muscles and nerves to be tested. Most patients find this test to be somewhat uncomfortable.
Evoked Potential (SSEP)
Somatosensory Evoked Potential is a test that shows the electrical signals of sensation going from the body to the brain. The signals show whether the nerves that connect to the spinal cord are able to send and receive sensory information like pain, temperature, and touch. This test evaluates a number of neurological problems, including spinal cord injuries, optic neuritis, multiple sclerosis and acoustic neuroma.
The SSEP indicates whether the spinal cord or nerves are being pinched. It is helpful in determining how much the nerve is being damaged and if there is a bone spur, herniated disc, or other source of pressure on the spinal cord or nerve roots. The Electromyography, or EMG is used to show if a nerve is being irritated or pinched as it leaves the spine on it way down the arm or leg. During a spine surgery, the EMG is used to monitor nerve output to the muscles in procedures where screws are being placed in the middle or lower part of the spine. The SSEP is used to check whether the sensory part of the nerve is working correctly.
Electroencephalography, or EEG, monitors brain activity through the skull. An EEG is used to help diagnose certain seizure disorders, brain tumors, brain damage from head injuries, inflammation of the brain and/or spinal cord, alcoholism, certain psychiatric disorders, and metabolic and degenerative disorders that affect the brain. EEGs are also used to evaluate sleep disorders, monitor brain activity when a patient has been fully anesthetized or loses consciousness, and confirm brain death.
This painless, risk-free test can be performed in a doctor's office or at a hospital or testing facility. Prior to taking an EEG, the person must avoid caffeine intake and prescription drugs that affect the nervous system. A series of cup-like electrodes are attached to the patient's scalp. These electrodes (also called leads) are small devices that are attached to wires and carry the electrical energy of the brain to a machine for reading.
Transcranial Doppler ultrasonography is a noninvasive technology that uses the Doppler Effect to measure the velocity and direction of blood flow in the vessels. Just as a siren's pitch sounds higher when its source is moving toward you and lower as it moves away, so too will ultrasound waves change pitch, or frequency, as they bounce off the red blood cells moving in the blood. It is these pitch changes that produce the audible sounds during the exam. The Transcranial Doppler (TCD) uses a handheld-pulsed low frequency Doppler transducer that enables recording of blood flow velocities from intracranial arteries through selected cranial foramina and thin regions of the skull. Analysis of the Doppler spectra allows display and calculation of peak systolic, peak diastolic, and mean velocities and pulsatility indices. Mapping of the sampled velocities as a color display of spectra in lateral, coronal and horizontal views locates the major brain arteries in three dimensions.