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Ring artifact

Last revised by Mohd Ashyiraff Ilani Bin Ismail on 24 Sep 2024

Citation, DOI, disclosures and article data

Citation:

Dawes L, Ismail M, Murphy A, et al. Ring artifact. Reference article, Radiopaedia.org (Accessed on 05 Oct 2024) https://doi.org/10.53347/rID-1988

DOI:

https://doi.org/10.53347/rID-1988

Permalink:

https://radiopaedia.org/articles/1988

rID:

1988

Article created:

2 May 2008, Laughlin Dawes

Disclosures:

At the time the article was created Laughlin Dawes had no recorded disclosures.

View Laughlin Dawes's current disclosures

Last revised:

24 Sep 2024, Mohd Ashyiraff Ilani Bin Ismail

Disclosures:

At the time the article was last revised Mohd Ashyiraff Ilani Bin Ismail had no financial relationships to ineligible companies to disclose.

View Mohd Ashyiraff Ilani Bin Ismail's current disclosures

Revisions:

27 times, by 20 contributors - see full revision history and disclosures

Sections:

Imaging Technology

Tags:

ct artefact, refs, artifact

Synonyms:

Ring artefacts
Ring artifacts
Ring artefact

Ring artifacts are a CT phenomenon that occurs due to the miscalibration or failure of one or more detector elements in a CT scanner. Less often, it can be caused by insufficient radiation dose or contrast material contamination of the detector cover ². One should be aware of this artifact as it can be misinterpreted as pathology if goes unchecked.

Features

This artifact usually occurs in 3rd generation CT machines because the detector row rotates around the patient. Miscaliberation of one detector will give erroneous readings around the patient as the detector moves, thus giving a circular artifact ¹.

However, ring artifacts seen in phantom may not be seen in clinical images because a wide window is used ¹.

They occur close to the isocenter of the scan and are usually visible on multiple slices at the same location. They are a common problem in cranial CT.

Solutions

Selecting the correct scan field using calibration data that are more closely fit with the anatomy of the patient may reduce artifact ¹.

Recalibration or repair of the detector will usually rectify the artifact ¹. Occasionally detector elements need replacing, which can be costly. The referring clinician should be notified that the concerning ring shadows are artifactual.

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