Artefact
Something on the image caused by the scanning process, not by anything in your body.
What it means
A distortion on the image produced by the scanning process rather than by anything inside you.
Common causes: moving or breathing during the scan, metal from a hip replacement, dental fillings, a pacemaker, jewellery, or simply the physics of the machine.
It is a picture-quality problem, not a health finding, and being told your scan showed artefact is not being told something is wrong.
In practice
In radiology reports, often explaining why part of a scan could not be assessed properly — "limited by motion artefact", "streak artefact from hip prosthesis".
Why it matters
Ask whether it affected the answer. Sometimes artefact obscures exactly the area of interest, and the scan needs repeating; often it does not matter at all.
If you are asked to repeat a scan for this reason, it is not because anything was found.
Next time, remove all metal and jewellery, and hold still and hold your breath when asked — those two things prevent most avoidable artefact.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 30, 2026