The CHOC Neuroscience Institute offers the full range of diagnostic services. The strength of our diagnostic services is our child-focused approach – from the small needles to collect blood for lab work to the small instrumentation for such diagnostic procedures as lumbar puncture. Parents and/or our child life specialists often stay with the child during these procedures. Our goal is to make the child as comfortable as possible during these tests.
Diagnostic procedures we offer at The CHOC Neuroscience Institute include:
• Computed tomography scan (CT scan) – This is a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. CT scans are more detailed than general X-rays. CT scans are often used to diagnose trauma, bleeding, stroke, masses or tumors, abnormal sinus drainage, sensorineural hearing loss, malformed bone or other tissues, brain abscess, cerebral atrophy (loss of brain tissue), cerebral edema (brain tissue swelling), and hydrocephalus (fluid collecting in the skull).
• EEG – An EEG, or electroencephalogram, is a recording of the electrical waves in the brain. It measures electrical impulses that are sent between nerve cells. This device is used to help diagnose the presence and type of seizure disorders, confusion, head injuries, brain tumors, infections, degenerative diseases and metabolic disturbances that affect the brain. It is used to evaluate sleep disorders and to investigate periods of unconsciousness. Abnormal EEG findings may indicate epilepsy, convulsion, any structural brain abnormality such as a brain tumor, brain infection, head injury, encephalitis (inflammation of the brain), hemorrhage (abnormal bleeding caused by a ruptured blood vessel), cerebral infarct (tissue that is dead because of a blockage of the blood supply), or a sleep disorder such as narcolepsy. An EEG uses small electrodes to measure the electrical activity within the brain. It does not deliver any electricity of its own. The technician uses a paste to attach 23 small electrodes to the person’s scalp. The electrodes carry information about the brain’s electrical activity to an amplifier. A special machine records the amplified brain waves, and produces a pattern of tracings called an electroencephalogram.
• MRI (magnetic resonance imaging) – This is a diagnostic test similar to a CT scan but which employs powerful magnets instead of X-rays to create precise pictures of body tissues using radio waves. These radio waves are not harmful to tissues, and the procedure is painless. However, it may require sedation because the child must remain absolutely still. MRI is especially useful in brain and neurological disorders because it can clearly show various types of nerve tissue. It provides clear pictures of the brain stem and posterior brain, which are difficult to view on a CT scan. It is also useful for the diagnosis of demyelinating disorders (disorders such as multiple sclerosis that cause destruction of the myelin sheath of the nerve) and can distinguish tumors or other lesions from normal tissues.
• Electrodiagnostic tests (i.e. electromyography [EMG] and nerve conduction velocity) – These studies evaluate and diagnose disorders of the muscles and motor neurons. During the nerve conduction studies, small electrical impulses are delivered to the arm or leg. During the EMG, a small needle is inserted into different muscles. The test takes ½ to 1-1/2 hours depending on the complexity of the problem and is usually very well tolerated. The impulses and needles are only slightly uncomfortable.
• Positron emission tomography (PET) scan – This computer-based imaging technique provides a picture of the brain’s activity rather than its structure by measuring levels of injected glucose that are labeled with a radioactive tracer.
• Arteriogram (also called angiogram) – This procedure provides a scan of arteries going to and through the brain.
• Spinal tap or lumbar puncture – Cerebrospinal fluid (CSF) surrounds the brain and spinal cord. A lumbar puncture, also called a spinal tap, is used to make an evaluation or diagnosis by examining this fluid. It is a useful diagnostic test for many neurological disorders, particularly infections and brain/spinal cord damage. The procedure is performed while the child lies on his side with legs curled up to the chest. A needle is placed between the small bones of the back to collect the fluid.
• Evoked potentials – These procedures record the brain’s electrical response to visual, auditory and sensory stimuli.
• Ultrasound (also called sonography) – This painless diagnostic imaging technique uses high-frequency sound waves and a computer to create images of blood vessels, tissues and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels. In this test, the child lies down and lotion is spread over the area to be scanned. A probe is then rubbed over the area and a video image can be seen on a monitor.