Reasons, types and procedure of an ultrasound

At a glance:

Facts about the thyroid – what you should know

What is sonography?

Sonography, also called ultrasound examination, is an imaging procedure used in medicine for diagnostics, preventive examinations and for monitoring the course of therapy.

This procedure uses sound waves that are above the human hearing range and are therefore inaudible (so-called ultrasound).

These ultrasound waves are emitted by the ultrasound device and penetrate the body inaudibly and painlessly. In the body, they are reflected by the various tissues (such as muscles, bones and organs) and sent back as echoes. These echoes are received by the device and converted into images that can be seen on a monitor (in the form of a so-called sonogram).

Since different tissues reflect ultrasound to varying degrees, a realistic (but black and white) image of these tissues can be created.

Ultrasound examination is particularly effective in soft tissue diagnostics and has the advantage that it is painless and does not expose people to radiation. Sonography is therefore often the first diagnostic procedure in the internal examination of patients.

How does a sonography work?

Normally, no special preparation is required for an ultrasound examination. However, depending on which part of the body is to be examined, it may be necessary to appear for the ultrasound examination on an empty stomach or, for example, with a full bladder.

The examination itself can be carried out standing, sitting or lying down – depending on where the area to be examined is located. Before starting, a colorless gel is applied to the transducer and/or the part of the body to be examined. This ensures that the ultrasound head has good contact with the skin and that the sound waves can penetrate the tissue better. The doctor then presses the transducer onto the skin and moves it back and forth until the required images are created.

Occasionally, you may need to hold your breath briefly during the examination so that a sharp image can be captured.

The duration of a sonography varies. It can last just a few minutes or more than half an hour, depending on which and how many organs are being examined.

Special types of sonography

To clarify certain medical issues, special forms of ultrasound examination are required:

• Contrast-enhanced sonography: This is a newer method that uses contrast agents to make the blood flow in vessels and organs more visible. These contrast agents are well tolerated and cause fewer side effects than the contrast agents used in X-ray, CT or MRI examinations. The procedure is particularly useful for assessing the supply of tumors or the blood flow in organs and vessels.

• Echocardiography: This uses ultrasound waves to produce detailed images of the heart. This method makes it possible to assess the structure and function of the heart as well as the blood flow in the heart valves and vessels.

• Doppler sonography: Also called duplex sonography, it makes the blood flow in the blood vessels visible and audible. The reflected echo of the moving red blood cells is made electronically audible and recorded as a curve. This helps to diagnose changes in the flow speed of the blood, which can indicate diseases such as arteriosclerosis or vascular constrictions. Doppler sonography is particularly useful in cardiac diagnostics and in obstetrics.

• 3D sonography: The method is an advanced imaging technique in which several two-dimensional ultrasound images are combined to form a three-dimensional image. This creates photorealistic representations or panoramic images. This technique is often used to create detailed images of organs or fetuses in the womb.

• Endosonographie: Also called endoscopic ultrasound (EUS), this is a special form of examination in which an endoscopy (examination) of the upper or lower digestive tract (esophagus, stomach, intestines) is combined with an ultrasound examination performed from the inside. It is used primarily when tumors are suspected.

What is examined during a sonography?

Sonography is used in many areas of medicine. The main examinations are:

• Organs of the abdomen and pelvis: For example, the liver, gallbladder, spleen, stomach, intestines, pancreas or urogenital tract are examined for stones or tumors.
• Thyroid: This makes it possible to see the size, shape and texture of the tissue. Possible lumps can also be diagnosed.
• Herz: To detect abnormalities of the heart or its function.
• Soft tissue: For example, to detect breast cancer or changes in the thyroid gland at an early stage.
• Vessels: To diagnose narrowing, blockages or bulges in arteries and veins.
• Fetuses: To assess the growth and development of the unborn child and to detect abnormalities.

Risks and side effects of sonography

Sonography is a cost-effective examination that can be repeated as often as you like. Ultrasound is harmless to the human body and can therefore be used without hesitation on babies, small children and pregnant women.

Unlike an X-ray or CT scan, there is no radiation exposure. Nevertheless, these alternative methods are necessary in some cases because sound waves do not penetrate bone or gas.