Aliasing artifact (CT)

Last revised by Andrew Murphy on 23 Mar 2023

Citation, DOI, disclosures and article data

Citation:

Murphy A, Wang K, Bell D, et al. Aliasing artifact (CT). Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-52109

DOI:

https://doi.org/10.53347/rID-52109

Permalink:

https://radiopaedia.org/articles/52109

rID:

52109

Article created:

22 Mar 2017, Andrew Murphy ◉

Disclosures:

At the time the article was created Andrew Murphy had no recorded disclosures.

View Andrew Murphy's current disclosures

Last revised:

23 Mar 2023, Andrew Murphy ◉

Disclosures:

At the time the article was last revised Andrew Murphy had no financial relationships to ineligible companies to disclose.

View Andrew Murphy's current disclosures

Revisions:

8 times, by 5 contributors - see full revision history and disclosures

Sections:

Radiography, Imaging Technology

Tags:

cases, snippet title

Synonyms:

Aliasing artefact (CT)

Aliasing artifact, otherwise known as undersampling, in CT refers to an error in the accuracy proponent of analogue to digital converter (ADC) during image digitisation.

Image digitisation has three distinct steps: scanning, sampling, and quantisation.

When sampling, the brightness of each pixel in the image is measured, and via a photomultiplier, creates an output analogue signal that is then due to undergo quantisation.

The more samples that are taken the more accurate the representation of the signal will be, hence if a lack of sampling has occurred the computer will process an inaccurate image resulting in an aliasing artifact.

The artifact has the appearance of Moiré patterns.