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ABOUT ABDOMINAL ULTRASOUND
Abdominal ultrasound, also known as abdominal sonography, is a painless,
noninvasive procedure where sound waves are used to produce images of the inside
of the body. The principle is comparable to the radar used to predict the
weather or to scan the sea for unseen objects. The reflected sound waved
are received in specialized instruments connected to the ultrasound machine,
called transducers. The transducer is a small, hand-held
device about the size of a fist. The radiologist or technician spreads a
lubricating gel on the patient’s abdomen in the area being examined, and then
presses the instrument firmly against the skin to perform the test. The
transducer is swept back and forth to image the part of the abdomen being
imaged. The transducers are connected to computers that form an image on a TV
screen. These images are interpreted by radiologists and are helpful in
diagnosing problems in the abdomen, especially gallbladder, liver, and kidney
problems. Imaging of the pancreas with ultrasound is often problematic
because gas in the bowels, which blocks the reflection of the high-frequency
sound waves, can limit the quality of the images. It is also used to guide
procedures such as liver biopsies, where a small needle is used to sample a core
of liver tissue for laboratory and pathology testing. It is also extremely
useful in detecting stones in the gallbladder, bile ducts, and kidneys. Shifts
in the reflected sound waves are useful to detect flow in major intraabdominal
blood vessels. This technique is known as Doppler imaging.
Ultrasound examination of the abdomen offers many advantages. It is
painless, noninvasive, and does not expose the patient to any radiation.
For examination of the bile ducts, looking for stones in the gallbladder, and in
looking at the liver, ultrasound can be superior to CT
scanning in many cases. Limitations include problems with resolution
(finding very tiny problems), and the problem in imaging through air-filled
bowel. Your doctor can use this important tool in helping to diagnose a
wide variety of conditions in the abdomen.
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