LC&EM-Ultrasound

> **What Exactly Happens in an Ultrasound:**
 * [[image:http://www.mothercareultrasound.com/2d_ultrasound.jpg width="414" height="310"]][[image:http://www.bioquest.org/icbl/projectfiles/ultrasound.jpg]]
 * The ultrasound machine transmits high-frequency (1 to 5 megahertz) sound pulses into your body using a probe.
 * The sound waves travel into your body and hit a boundary between tissues (e.g. between fluid and soft tissue, soft tissue and bone).
 * Some of the sound waves get [|reflected] back to the probe, while some travel on further until they reach another boundary and get reflected.
 * The reflected waves are picked up by the probe and relayed to the machine.
 * The machine calculates the distance from the probe to the tissue or organ (boundaries) using the speed of sound in tissue (5,005 ft/s or1,540 m/s) and the time of the each echo's return (usually on the order of millionths of a second).
 * The machine displays the distances and intensities of the echoes on the screen, forming a two dimensional image like the one shown below.

Benefits

 * Ultrasound scanning is noninvasive (no needles or injections) and is usually painless.
 * Ultrasound is widely available, easy-to-use and less expensive than other imaging methods.
 * Ultrasound imaging uses no ionizing radiation.
 * Ultrasound scanning gives a clear picture of soft tissues that do not show up well on x-ray images.
 * Ultrasound causes no health problems and may be repeated as often as is necessary if medically indicated.
 * Ultrasound is the preferred imaging [|modality] for the diagnosis and monitoring of pregnant women and their unborn infants.
 * Ultrasound provides real-time imaging, making it a good tool for guiding [|minimally invasive] procedures such as [|needle biopsies] and [|needle aspiration] of fluid in joints or elsewhere.

Risks

 * For standard [|diagnostic ultrasound] there are no known harmful effects on humans.

[| Ultrasound Tutorial]
 * Purpose of a Fetal Ultrasound:**
 * **Confirm the pregnancy and its location.** Some embryos develop in the fallopian tube instead of in the uterus. An ultrasound exam can help your health care provider detect and treat a tubal (ectopic) pregnancy before it endangers your health.
 * **Determine your baby's gestational age.** Knowing the baby's age can help your health care provider more accurately determine your due date and track various milestones throughout your pregnancy.
 * **Confirm the number of babies.** If your health care provider suspects a multiple pregnancy, an ultrasound may be done to make sure.
 * **Evaluate your baby's growth.** Your health care provider can use ultrasound to make sure your baby is growing at a normal rate. Ultrasound can be used to monitor your baby's movement, breathing and heart rate as well.
 * **Study the placenta.** The placenta provides your baby with vital nutrients and oxygen-rich blood. Any problems with the placenta need special attention.
 * **Identify possible fetal abnormalities.** An ultrasound can help your health care provider detect many congenital abnormalities. An early diagnosis may lead to early interventions that help save or improve a baby's life.
 * **Investigate bleeding and other worrisome signs or symptoms.** If you're bleeding or having other complications, an ultrasound may help your health care provider find out what's going on.
 * **Perform other prenatal tests.** Your health care provider may use ultrasound to guide needle placement during certain prenatal tests, such as checking a sample of amniotic fluid for specific genetic problems (amniocentesis) or testing a sample of the placenta for genetic abnormalities (chorionic villus sampling).

March of Dimes info on how to prevent birth defects:

Ultrasound and other prenatal tests can let a woman know if her baby has certain birth defects or other special risks. Knowing about the problems before birth provides time to plan the baby's treatment. There are some basic things all women can do to reduce their childbearing risks and increase their chances for a healthy pregnancy and a healthy baby:
 * Plan for pregnancy by seeing a health care provider before you conceive.
 * Take a multivitamin containing 400 micrograms of the B vitamin folic acid daily starting before pregnancy and during early pregnancy to help prevent serious birth defects of the spinal cord and brain.
 * Get early and regular prenatal care.
 * Eat a variety of nutritious foods, including foods that are fortified with folic acid and foods that contain folate, the natural form of folic acid found in foods. Many grain products, including flour, rice, pasta, bread and cereals, are fortified with folic acid. Folate-rich foods include green leafy vegetables, dried beans, legumes, oranges and orange juice.
 * Begin pregnancy at a healthy weight (not too heavy or too thin), and gain the recommended amount of weight during pregnancy (25 to 35 pounds for women who begin pregnancy at a normal weight).
 * Don’t drink alcohol during pregnancy.
 * Don’t smoke during pregnancy and avoid secondhand smoke.
 * Don’t use any drug, even over-the-counter or herbal medications, unless recommended by a health care provider who knows you are pregnant.
 * Don’t eat undercooked meat or change a cat’s litter box. Both can cause a parasitic infection called toxoplasmosis that can cause birth defects in the baby.

What types of ultrasound are there?
There are basically seven different ultrasound exams, but the principle process is the same. The different types of procedures include:


 * Transvaginal Scans:** Specially designed probe transducers are used inside the vagina to generate sonogram images. Most often used during the early stages of pregnancy.


 * Standard Ultrasound:** Traditional ultrasound exam which uses a transducer over the abdomen to generate 2-D images of the developing fetus.


 * Advanced Ultrasound:** This exam is similar to the standard ultrasound, but the exam targets a suspected problem and uses more sophisticated equipment.


 * Doppler Ultrasound:** This imaging procedure measures slight changes in the frequency of the ultrasound waves as they bounce off moving objects, such as blood cells.


 * 3-D Ultrasound:** Uses specially designed probes and software to generate 3-D images of the developing fetus.


 * 4-D or Dynamic 3-D Ultrasound:** Uses specially designed scanners to look at the face and movements of the baby prior to delivery.


 * Fetal Echocardiography:** Uses ultrasound waves to assess the baby's heart anatomy and function. This is used to help assess suspected congenital heart defects.

http://health.howstuffworks.com/ultrasound1.htm http://www.radiologyinfo.org/en/info.cfm?pg=genus&bhcp=1#part_five http://www.cnn.com/HEALTH/library/PR/00054.html http://www.americanpregnancy.org/prenataltesting/ultrasound.html