CT Scans Diagnostic

Date: 2015-10-07; view: 489.

Computed tomography (CT scan), is a painless process used to produce rapid, clear two-dimensional images of organs, bones, and tissues. 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, a blood clot or intracranial bleeding in patients with stroke, brain damage from head injury, and other disorders.

Scanning takes about 20 minutes. The patient lies on a special table that slides into a narrow chamber. A sound system built into the chamber allows the patient to communicate with the physician or technician. X-rays are passed through the body at various angles and are detected by a computerized scanner. The data is processed and displayed as cross-sectional images of the internal structure of the body or organ.

Electroencephalography(EEG), monitors brain activity through the skull. EEG is used to help diagnose certain seizure disorders, brain tumors, brain damage from head injuries, inflammation of the brain 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.

A series of cup-like electrodes are attached to the patient's scalp, either with a special conducting paste or with extremely fine needles. The 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. A very low electrical current is sent through the electrodes and the baseline brain energy is recorded. The electrodes transmit the resulting changes in brain wave patterns. Since movement and nervousness can change brain wave patterns, patients usually recline in a chair or on a bed during the test, which takes up to an hour.

Electromyography (EMG) is used to diagnose nerve and muscle dysfunction and spinal cord disease. It records the electrical activity from the brain 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 lasts about an hour.

An EMG is usually done in conjunction with a nerve conduction velocity (NCV) test, which measures electrical energy by assessing the nerve's ability to send a signal. A technician tapes two sets of flat electrodes on the skin over the muscles. The first set of electrodes is used to send small pulses of electricity (similar to the sensation of static electricity) to stimulate the nerve that directs a particular muscle. The second set of electrodes transmits the responding electrical signal to a recording machine. The physician then reviews the response to verify any nerve damage or muscle disease. There is no discomfort or risk associated with this test.

Electronystagmography (ENG) describes a group of tests used to diagnose involuntary eye movement, dizziness, and balance disorders, and to evaluate some brain functions. Small electrodes are taped around the eyes to record eye movements. If infrared photography is used in place of electrodes, the patient wears special goggles that help record the information. Both versions of the test are painless and risk-free.

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