Artifacts in ultrasound

The occurrence of artifacts should be understood that sonographer / sonologist can minimize diagnostic interpretation errors that may occur. Some of the artifacts that often occur on ultrasound examination are:
1. Good group of artefacts
a. Acoustic shadow (acoustic shadow), a reduction in the intensity of the echo in the back of the masses, due to strong attenuation in the upper network
 

Figure 1. Acoustic shadow
Source: Ultrasound in Emergency Care, Adam Brooks

b. Enhancement, the sound waves passing through the liquid does not have a strong attenuation, so it looks lighter fluid below.

 

Figure 2. Enhancement
Source: Ultrasound in Emergency Care, Adam Brooks

c. Comet tail. Image looks like a comet's tail has ang caused by multipath reflections

Figure 3. Comet Tail
Source: Ultrasound in Emergency Care, Adam Brooks

2 . The bad artifacts
a. Multiple Reflection (reverberasi), occurs due to the reflection of a barrage of two layers (or more) of each adjacent reflector.

Figure 4. Reverberation artifacts
Sources: Lecture Materials D4, Artefak

b. Multipath reflection, an artifact that arises from repeated reflection of the ultrasound beam in different directions before returning to the transducer, giving rise to mirror image

Figure 5. Mirror image
Source: Ultrasound in Emergency Care, Adam Brooks

 

Figure 6. multipath reflection artifact
1. Boundary line between liver and diaphragm
2. The line between the diaphragm and lungs
3. Line of mirror image artefact
D = muscular diaphragm
Source: Collection of files lectures, Artefak

c. Anisotropic reflector, is a hyperechoic image artifacts caused, if the ultrasound beam perpendicular from the transducer, and hypoechoic when the beam ultrasonic oblique.

d.Beam artifacts, is an artifact that occurs when the object is smaller than the width of the emission ultrasound.Sehingga image depicted is a combination of object and surrounding tissue.

e.Side Grating Lobe and Lobe
Side Lobe, and Grating lobes appear in the form of additional echoes at the edge of a strong reflector.This occurs because of the additional ultra-sound emitted by the transducer in addition to the sound file
 

Figure 7. Side lobe artifacts. In the picture there is a duplication of the right azygos vein, normally in the picture
nothing left.

3. Group of ugly artifacts

• Motion artifacts, this happens to wear color doppler which sector or mechanical Annular Array probes.Because the transducer is driven by the motor so that it can cause a doppler frequency deviation of the actual velocity of blood flow.
• .Elektrical Noise / Artifacts Cross Talk, is an artifact caused by electrical interference and cross talk within the system. It is more easily detected and treated with a good grounding system.

(by: Mrs.Any  Maryani, S.ST)