Ultrasound Image Artifact and Their Sources
In this installment, we will look at image artifacts, a common service issue with diagnostic ultrasound. Image artifacts are described in many ways but are essentially the areas of the image with missing information (dropouts) and static (non-moving) and/or dynamic (moving) artifacts.
When a service call comes in for image artifacts in general, the first item we want to address is the transducer. If the customer tries a different transducer with the same format (ideally linear or curvilinear) and the issue goes away, we have determined the probe is the issue and we are done. We also want to ask the customer to try different ports on the ultrasound system to eliminate a connector board issue. These two trouble- shooting techniques can be done over the phone, eliminating a service visit.
If the artifact is not identified using the above techniques and it is static, we want to look at the front end (or beam- former, image former, acquisition subsystem) of the system. Most console-based ultrasound systems have multiple boards of the same type in the front end such as transmitters, receivers, and beamformers. As a troubleshooting tool, you can exchange these boards with others of the same type to see if the artifact moves. If it does, the board you rotated is the source of the artifact.
If the artifact is dynamic (moving), we still want to look at the transducer and front end boards but now we want to look at the environment as well. Is the artifact electronic noise? Noise issues are some of the most difficult issues to isolate with ultrasound systems. The first step is to move the system to another area of the facility and use a different circuit for power. This accomplishes two things; first, we are moving the system away from a potential noise generating source (tread- mills, fluorescent light ballasts, fans etc.) and second, you are isolating the power as a potential source. You also want to check the ground continuity of the sys- tem to ensure you have a solid ground.
For those of you servicing the GE Logiq 9 systems, there is an inherent issue with the card cage cover where the points of contact between the cover and the cage itself oxidize slightly which degrades the ground plane of the front end, causing noise. GE has an improved cover and a retrofit kit with additional grounding but we still see it as a cause for 2D and Color Doppler artifacts. The solution is to remove the cover and clean all points of contact.
Image artifacts are one of the most common service issues with diagnostic ultra- sound systems and by using the above suggestions, you can speed up the diagnosis.