What is an ultrasound?
An ultrasound test is a radiology technique, which uses high-frequency sound waves to produce images of the organs and structures of the body. The sound waves are sent through body tissues with a device called a transducer. The transducer is placed directly on top of the skin, which has a gel applied to the surface. The sound waves that are sent by the transducer through the body are then reflected by internal structures as "echoes." These echoes return to the transducer and are transmitted electrically onto a viewing monitor. The echo images are then recorded on a plane film and can also be recorded on videotape. After the ultrasound, the gel is easily wiped off.
The technical term for ultrasound testing and recording is "sonography." Ultrasound testing is painless and harmless. Ultrasound tests involve no radiation and studies have not revealed any adverse effects.
For what purposes are ultrasounds performed?
Ultrasound examinations can be usedin various areas of the body for a variety of purposes. Thesepurposes include examination of the chest, abdomen, bloodvessels (such as to detect blood clots in leg veins) and the evaluation of pregnancy. In the chest, ultrasound can be used to obtain detailed images of the size and functionof the heart. Ultrasound can detect abnormalities of the heartvalves, such as mitral valve prolapse, aortic stenosis, and infection(endocarditis). Ultrasound is commonly used to guide fluid withdrawal(aspiration) from the chest, lungs, or around the heart. Ultrasoundis also commonly used to examine internal structures of the abdomen. Gallstones in the gallbladder are easily detected, as are kidneystones. The size and structure of the kidneys, the ureters, liver,spleen, pancreas, and aorta within the abdomen can be examined.Ultrasound can detect fluid, cysts, tumors or abscess in the abdomenor liver. Impaired blood flow from clots or arteriosclerosis in the legs can be detected by ultrasound. Aneurysms of the aorta can also be seen. Ultrasound is also commonly used to evaluate the structure of the thyroid gland in the neck.
During pregnancy, an ultrasound can be used to evaluate the size,gender, movement, and position of the growing baby. The baby'sheart is usually visible early, and as the baby ages, body motionbecomes more apparent. The baby can often be visualized by themother during the ultrasound, and the gender of the baby is sometimes detectable.
How do patients prepare for an ultrasound?
Preparation for ultrasound is minimal.Generally, if internal organs such as the gallbladder are to beexamined, patients are requested to avoid eating and drinkingwith the exception of water for six to eight hours prior to theexamination. This is because food causes gallbladder contraction,minimizing the size, which would be visible during the ultrasound.In preparation for examination of the baby and womb during pregnancy,it is recommended that mothers drink at least four to six glassesof water approximately one to two hours prior to the examinationfor the purpose of filling the bladder. The extra fluid in thebladder moves air-filled bowel loops away from the womb so thatthe baby and womb are more visible during the ultrasound test.
Copy from:http://www.answers.com/ultrasound
External links :
|
