Myelography Health Dictionary

The most common type of motor neuron disease is amyotrophic lateral sclerosis ( or Lou Gehrig’s disease). It usually affects people over the age of 50 and is more common in men. Some cases run in families. Usually, symptoms start with weakness in the hands and arms or legs, and muscle wasting. There may be irregular muscle contractions, and muscle cramps or stiffness. All four extremities are soon affected.

Progressive muscular atrophy and progressive bulbar palsy both start with patterns of muscle weakness different from but usually develop into.There are 2 types of motor neuron disease that first appear in childhood or adolescence. In most cases, these conditions are inherited. Werdnig–Hoffman disease affects infants at birth or soon afterwards. In almost all cases, progressive muscle weakness leads to death within several years. Chronic spinal muscular atrophy begins in childhood or adolescence, causing progressive weakness but not always serious disability.

There are no specific tests for motor neuron disease. Diagnosis is based on careful clinical examination by a neurologist. Tests including EMG, muscle biopsy, blood tests, myelography, CT scanning, or MRI may be performed.

The disease typically goes on to affect the muscles involved in breathing and swallowing, leading to death within 2–4 years. However, about 10 per cent of sufferers survive for 10 years.

Nerve degeneration cannot be slowed down, but physiotherapy and the use of various aids may help to reduce disability. The drug riluzole is used to extend life (or the time until mechanical ventilation is required).... motor neuron disease

X-rays are produced artificially by bombarding a heavy metal tungsten target with electrons, in a device known as an X-ray tube. Low doses of the X-rays that are emitted are passed through body tissue and form images on film or a fluorescent screen. The X-ray image, also known as a radiograph or roentgenogram, shows the internal structure of the area that is being examined. Dense structures, such as bone, absorb X-rays well and appear white on an Xray image. Soft tissues, such as muscle, absorb less and appear grey.

Because X-rays can damage living cells, especially those that are dividing rapidly, high doses of radiation are used for treating cancer (see radiotherapy).

Hollow or fluid-filled parts of the body often do not show up well on X-ray film unless they first have a contrast medium (a substance that is opaque to X-rays) introduced into them. Contrastmedium X-ray techniques are used to image the gallbladder (see cholecystography), bile ducts (see cholangiography), the urinary tract (see urography), the gastrointestinal tract (see barium X-ray examinations), blood vessels (see angiography; venography), and the spinal cord (see myelography).

X-rays can be used to obtain an image of a “slice” through an organ or part of the body by using a technique known as tomography. More detailed images of a body slice are produced by combining tomography with the capabilities of a computer (see CT scanning).

Large doses of X-rays can be extremely hazardous, and even small doses carry some risk (see radiation hazards).

Modern X-ray film, equipment, and techniques produce high-quality images with the lowest possible radiation exposure to the patient.

The possibility of genetic damage can be minimized by using a lead shield to protect the patient’s reproductive organs from X-rays.

Radiographers and radiologists wear a film badge to monitor their exposure to radiation.

(See also imaging techniques; radiography; radiology.)... x-rays