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I received a call the other day from a customer stating they had moving lines throughout the image area. These lines were curved and started at the top of the image area, slowly moving down and across. They appeared to be similar to spokes of a bicycle. After asking a few questions, I was able to determine the cause of the lines and offered up a solution. Here are some tips for troubleshooting noise and artifacts on an ultrasound system.
First, determine what type of image problem we are seeing on the screen. There are four main problems that we usually see. They are dropouts, artifacts, noise and banding.
Dropouts are an actual loss of image. They normally manifest as black lines running down the image. You will want to determine if the issue is with the probe or the system. Try moving the probe cable and connector on the system to see if dropout moves/changes. Also try testing multiple probes on different ports and on another system. All of this will help determine if it is caused by the probe or the system.
Artifacts are objects in the image area that should not be present, normally dots and lines that interfere with the image. They are usually confined to a specific portion of the imaging area and can look like snow or lines. Common causes are the boards associated with transmit/receive.
Noise is a subcategory of artifacts but generally covers a larger area of the image and are random. Noise can be described as speckles or lines in the image area. Noise can be seen in all imaging modes such as 2D, color or PW Doppler. Here, possible sources include probes, channel/TR boards or the power supply.
Banding is where a line is seen horizontally across the image area. The banding can be dark or light. Banding manifests itself in two ways, solid or moving. Solid banding is normally caused by one of the time gain control potentiometers. A defective or failing potentiometer will leave the portion over- or under-compensated. The other banding is a moving line that rolls from the top to the bottom and side to side, again described much like the spokes of a bicycle. This is called a 60 cycle hum and is commonly picked up through the AC line. One of the main causes we have run across is when a MRI or X-ray machine is nearby. Try moving the system to another room. If this is not feasible then you will want to install an AC isolation transformer in-line with the ultrasound system.
While there are many causes for these issues, I always follow one rule of thumb … if the issue is horizontal, it’s the back end. If it’s vertical then it’s the front end. This little tip will save you a lot of time troubleshooting.
For more ultrasound technical tips and tricks, or to view technical support videos visit www.conquestimaging.com. See our online installation and removal videos. Conquest Imaging Technical Support is available 24/7/365 at 866-900-9404.
Mike Davis is a Technical Support Specialist at Conquest Imaging.
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