CT artifacts

CT artifacts are common and can occur for various reasons. Knowledge of these artifacts is important because they can mimic pathology (e.g. partial volume artifact) or can degrade image quality to non-diagnostic levels.
CT artifacts can be classified according to the underlying cause of the artifact.
Patient-based artifacts
Physics-based artifacts
- beam hardening
- cupping artifact
- streak and dark bands
- metal artifact/high-density foreign material artifact
- partial volume averaging
- quantum mottle (noise)
- photon starvation
- aliasing in CT
Hardware-based artifacts
- ring artifact
- tube arcing
- out of field artifact
- air bubble artifact
- Helical and multichannel artifact
- windmill artifact
- cone beam effect
- multiplanar reconstruction (MPR) artifact