What is the principle of an ultrasound scan?
An ultrasound scan is a completely harmless and perfectly painless imaging technique. Its principle is based on the reflection of a beam of ultrasound waves. That reflection varies according to the nature and density of the medium traversed. Ultrasound waves are generated by a probe applied to the skin. The probe emits and then receives the beam’s reflections. The results are instantly displayed as images on a screen, thus creating a movie in real time. Some of those images can be captured and then printed on paper or on film.
What information does an ultrasound scan provide?
An ultrasound scan allows our doctors to analyze the morphology of the studied structures (localization, size, homogeneity, and consistency). For instance, an abdominal ultrasound scan could be performed to analyze the digestive organs (liver, spleen, pancreas), a renal ultrasound scan to analyze the kidney and renal pathways, and so forth. Such scans can visualize numerous abnormalities. They can be very specific, particularly in the case of cysts.
Should special precautions be taken before or after an ultrasound scan?
This safe, non-irradiating technique is particularly indicated for pregnant women, children, and women of childbearing age. Prior to an abdominal ultrasound, the patient must be fasting (no solid food, drink or cigarette) for at least 6 hours. For pelvic ultrasound in women (and children), or for endoscopic or prostatic ultrasound scan, the bladder should be full. The patient should therefore drink a good amount of water an hour before the examination, and especially refrain from urinating.
In practice, how is an ultrasound scan done?
If you were the patient, you would be lying on your back, in a semi-sitting position, or lying on your side, on the examination table, depending on the type of scan being performed. The sonographer would first apply a gel on your skin, just in the vicinity of the organ being studied. The gel improves the contact with the probe. While watching live pictures displayed on a computer screen, the sonographer would then smoothly slide the probe on your body, gently varying the pressure on your skin. At times, the sonographer might ask you to stay still in certain positions.
How long is the scan ?
The duration of the examination varies according to the nature of the organ explored. It can last from 15 to 45 minutes.