An introduction to X-ray CT artefacts
Any difference between the reconstructed image obtained with an X-ray CT scan with the real sample, based on its material density and structure, is referred to as a CT image artefact.
On top of that, when conditions are not met when scanning a sample, artefacts will appear. Image artefacts have a regular pattern and show as bright and/or dark lines or shadows in scans.
As seen in these pictures, artefacts before and after correction: