Ultrasound screenings  >> back to the newsletter overview

Today, almost every examination in internal medicine uses the technical possibilities of ultrasound screenings. These are meant to provide some general information and answer frequently asked questions without focusing on specific symptoms or disease patterns.

What actually is ultrasound?

A device with a crystal surface applied directly on the body is used to transmit onto, conduct through and let reflect its very fast movements from the organs lying underneath. You may compare this to a cell phone lying on a table with its vibrations still noticeable at the other end of the table. For medical purposes, the frequency (number of oscillations per second) of the vibration used is a thousand times higher than the one of audible sound; it is therefore called ultrasound.

The ultrasound sender is also the receiver of the reflected sound waves. This part of the device is called a “transducer”. It is connected to a computer with specialized processors that measure the distance between the sender and the reflecting structure within the short time between the sending of the ultrasound impulse and the reception of the reflected signal. This marks a pixel on the screen. By placing many vibrating crystals next to each other and sending many impulses per second, the large number of marked pixels will then create a picture matching a cross section image of the corresponding body area. This is comparable to a cross section of the sea that a fishing boat will receive when looking for a shoal of fish with its sonar and that will display on its screen as sound reflecting points.

Are ultrasound screenings harmful?

So far, there has been no evidence of any harmfulness. The examinations can be repeated as often as necessary, which makes for the main difference of this technology compared with radiation-based screenings such as x-rays or computer tomographies (CT). Their unavoidable radiation will always cause cell damages.

Several new ultrasound procedures have been developed to deal with particular issues (e.g. color duplex/contrast sonography). These screenings leave a larger amount of “sound energy” in the examined tissue and thereby cause a slight warming of the area; hence, it is recommended to keep examinations brief in the case of pregnant women and small children.

What is possible with ultrasound screenings and what is not?

A cross section can be examined of any organ or structure having a certain volume or being filled with liquid. The surface of an organ or of a certain part of it is not displayable, though.

Compare it to an apple; if you cut it in half, the section will show the core, rotten bits in the flesh, possibly a worm hole, etc. You won’t be able to see, however, if the skin is red or green, dirty or moldy. In the same manner, a section image of the liver can show suspicious tissue (e.g. a tumor); a section image of the gall bladder filled with bile can display stones. From a cross section of a filled stomach, however, one cannot say if there is an inflammation in the mucous membrane of the displayed stomach wall; the surface would have to be checked to do so (e.g. during a gastroscopy).

The characteristics of moving liquids can well be displayed, e.g. the blood flow. Together with a picture of a thickened artery wall, the stenosis degree can exactly be assessed with a given accelerated blood flow. Other important characteristics of the blood cannot be identified by ultrasound. The screening cannot reveal anything about a potential anemia or the blood oxygen level, for instance.

What can we do for you?

The quality of an ultrasound screening heavily depends on the experience and the expertise of the physician and on the technical conditions, i.e. the ultrasound devices and the transducers used in the examination.

All physicians at PKD am Städel (Praxisklinik für Diagnostik) are long experienced with ambulatory and clinical ultrasound diagnostics. Some of them are members of DEGUM (Deutsche Gesellschaft für Ultraschall in der Medizin).

They work with state-of-the-art sonography devices (Acuson Sequoia 512/ X700/S2000 by Siemens), using the latest technology (color duplex, contrast sonography, 3D sonography, elastography).

Here you will find a more detailed description of the different examinations.

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