The medical community depends on the accuracy of images created by CT Scanners. And most of the time, the images are accurate representations of the object that’s scanned. However, a number of image anomalies like streak artifacts can commonly occur.
What Is A Streak Artifact?
The name says it all: there’s a dark streak in the CT image and it usually appears between metal, bone, iodinated contrast, barium and other high-attenuation materials. But what causes it? It usually happens when the beam hardens and scatters. You’ll see bright streaks adjacent to dark ones.
Beam hardening is an interesting occurrence. Think of yourself as an X-ray beam and you are running a race in the part of the body that is being scanned. You are running against a strong head wind and you lose energy and slow down the longer the wind is in your face. You expend more energy to maintain your pace as you run into the wind. Likewise, X-rays can lose their energy or “harden” more quickly when they pass through metal or bone rather than going through muscles or organs.
Compton Scatter can also cause streak artifacts. Scatter causes X-ray photons to change energy and direction. As they move, they can end up in a different detector than they are supposed to be. If scattered photons end up in a detector that would usually have very few photons, it can be an issue. For example, should a metal implant block all of the photons, the corresponding detector element could only detect the scattered photos.
By using newer reconstruction techniques or metal artifact reduction software, you can reduce streak artifacts. By scanning at a higher kV, a radiologist could also get a harder X-ray beam and fewer beam hardening artifacts. However, since the higher kV will reduce the tissue contract of the scan, it’s a tradeoff.
So what do you do if your reduction software and reconstruction techniques are current and the radiologist is scanning with the highest kV they feel comfortable with and you’re still experiencing streak artifacts? In all likelihood, you’ll need to get a service engineer to diagnose the underlying issues.
Talk to An Expert
Are you looking for a new CT Scanner? Having issues with your current one? The experts at Atlantis Worldwide are happy to help. We’ve been helping hospitals, clinics, practices and urgent care facilities with their medical imaging needs and issues for more than 27 years. Contact Us Today!
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Meet the author: Vikki Harmonay