Ultrasound examinations | CLINICAL CENTRE

In ultrasound examinations organs can be distinguished on the basis of their acoustic features, that is their sound reflecting properties. The principle of ultrasound imaging is that the sound waves from the probe (called transducer) are absorbed or reflected at a different extent by the different tissues.   Certain pathologic conditions change the sound reflecting capacity of the organs, which makes these conditions detectable. The advantage of this procedure is the fact that it is completely safe, does not do any biological harm to the body, and can be repeated several times if necessary.  The probe of the ultrasound device emits high-frequency sound waves (ultrasounds) having a frequency range above that of human hearing range. Part of these sound waves is reflected from certain surfaces in a scattered form, while the other part is absorbed. The reflected waves - like in the case of sonars - are received and collected by the probe, which turns them into electrical signals that the computer uses to create an image on the monitor.  Whereas ultrasound can travel easily through liquids and compact organs, structures like gall stones, intestinal gases or bones will reflect it; therefore, the areas behind them fall into “acoustical shadow” and cannot be formed an opinion on. Most devices used today are suitable for the examination of several body regions; however, the different examinations may require probes of different size, shape or frequency.  US is also suitable for the examination of the breast, salivary glands in the neck, vessels, the thyroid, inguinal vessels and the adjacent lymph nodes, the eyes, the testicles, and basically all the skeletal muscles and joints, and even the brain of babies before the bones of the skull have grown together (through the fontanel).  For ultrasound examinations patients lie face-up on the exam table. They need to remove all clothing in the abdominal region. The radiologist will apply some gel to the skin to enhance passing of ultrasound waves into the body. The transducer is placed on the skin and may also be pressed lightly against the abdomen. The physician will move the transducer back and forth to get an image of the individual organs. Abdominal ultrasound examinations, especially if the gall ducts and the pancreas is also examined, can only be successful if the patient has an empty stomach. Patients are recommended not to eat 4-6 hours before the examination. Nevertheless, they can take their regular medications with a sip of water - this does not interfere with the examination.  The urinary bladder and the adjacent organs can only be examined successfully if the bladder is full of urine. Therefore, patients are recommended to drink plenty of fluids (preferably non-carbonated) a few hours prior to examination.   If the patient being examined has diabetes, he or she should ask the referring physician if his/her medication can be taken before the examination, whether the insulin can be administered, and if he/she can have breakfast. This procedure does have its limitations. Gall stones or abnormalities in the liver, for example, may take repeated examinations to be detected.   Proper preparation increases efficiency; however, the presence of plenty of air in the bowels can be extremely interfering.   If the gel sticks to your clothes, it can be removed easily by washing.  The procedure has no known harmful effects, can be repeated as many times as needed. The examination itself should not be painful. Nevertheless, you may feel it uncomfortable when the transducer is pressed against your abdomen when looking for the underlying cause of abdominal pain (for example gall bladder inflammation).