Ultrasonic device and its widespread use is one of the greatest achievements of the modern medicine. It is a simple and usually non-invasive test, which does not expose the examined to any form of radioactive energy.
The principle is a device that emits ultrasonic sound waves from a special probe. These sound waves can not be heard as they have a very high frequency. In addition, the probe has ability to capture ultrasonic waves reflected back by various structures of the body. The device is capable of form an image from the received information and this way it can depict deep tissues and organs. Classic forms of ultrasonography need the probe to be in tight contact with the skin, which is enabled by a layer of special conducting gel.
Some types of the ultrasonography may include the possibility to use a smaller probe, which is inserted into a body cavity and this allows to see the local situation from within. This is the case of transesophageal echocardiography, vaginal ultrasound in gynecology and endosonography of the digestive tract.
The classic ultrasound usually does not need any special preparation with the exception of abdominal ultrasonography, which should be performed on an empty stomach. The presence of food in stomach significantly impairs the results. In addition, abdominal ultrasonography should not be performed after recent upper GI endoscopy or colonoscopy. These endoscopic methods use air to inflate the digestive tract and the air totally disrupts the visibility in ultrasonography.
If we want to focus the examination on the urinary bladder, the patient should not urinate before the examination. Filled bladder is much easier to view and evaluate than the one emptied.
Ultrasound has a very wide use, particularly in internal medicine and gynecology. Most often performed are the following forms of ultrasonography:
Ultrasonography of the abdomen
It is relatively quick and very useful examination that well displays the structure of the liver, gallbladder, biliary tract, pancreas, intestines, kidneys, urinary bladder, gynecological structures and prostate in men. Together with abdominal X-ray, abdominal ultrasound is an ideal first-line examination in patients with acute abdominal pain.
Ultrasonography of the heart (echocardiography)
Echocardiography is the main examination method of non-invasive cardiology. It can easily show the anatomical and functional condition of the heart. It is an irreplaceable examination procedure of modern cardiology. Its special subtype is known as the transesophageal echocardiography when the probe is inserted into the patient's esophagus. More information can be found in article dedicated to echocardiography.
Ultrasonography in pregnancy
Regular ultrasonography is a part of screening examination that aims to find any common congenital disorders. The ultrasound helps to evaluate the size and growth of the fetus, its heart rate and many anatomical defects.
Ultrasonography of the blood vessels
Ultrasonography of the chest (except the heart)
The ultrasonography is very effective when we suspect the presence of a pleural effusion. The ultrasound helps to confirm the "fluid on lungs", to evaluate its amount and it may show a spot where a safe puncture is possible.
Ultrasonography of breasts
Ultrasonography of the neck
The examination is a little bit subjective and it depends on attention and experience of the examiner. To a certain extent, the same ultrasound finding may be interpreted in more ways by more investigating doctors. However, certain values can be measured and this makes the results more objective. Abdominal ultrasound is in many ways less accurate than computed tomography, which should be performed when the ultrasonographic finding is uncertain. Other disadvantage is the fact that the ultrasonic waves do not penetrate bones and this practically excludes the ultrasound from brain examination.
The examination is widely available in every hospital (in developed countries, of course). It is painless, non-invasive and does not expose people to radiation. Therefore, it is a great examination method in pregnancy and in children.