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Table of contents

Understanding Imaging Performance (3): Artefacts

Artefacts in CT

Artefacts: definition

Types of artefact

Artefact origins

Beam hardening

Beam hardening effect on scan profile

Beam hardening: cupping artefact

Avoiding beam hardening artefacts

Beam hardening: calibration correction

Beam hardening correction software

Reduction of streaks and bands

Partial volume effect

Partial volume artefact

Partial volume artefacts

Minimizing partial volume artefacts

Photon starvation

Avoidance using mA modulation

Adaptive filtration

Multi-dimensional adaptive filtering

Effects of 3D filtration

Undersampling

Avoidance of undersampling artefacts

Metal artefacts

Avoidance of metal artefacts

Software corrections for metal artefacts

Metal Artefact Reduction

Patient motion artefacts

Minimizing motion artefacts

Motion artefact correction

Inadequate scan field

Detector sensitivity - Ring artefacts

Ring artefacts

Artefacts in helical scanning

Artefacts in the transverse plane

Helical artefacts (Pitch 2)

Helical artefacts - Abdomen

Minimization of helical artefacts

Artefacts in multiplanar and 3D reconstructions

Stair step artefacts

Zebra artefact

Multislice scanner artefacts

Appearance of helical artefacts in multi-slice

“Windmill” artefact

Windmill artefact in consecutive slices

Effect of interpolator on artefacts

Effect of pitch on artefacts

Cone beam effect

Cone beam effect (2)

Cone beam effect (3)

Cone beam effect (4)

Cone beam artefact

Cone beam reconstruction

Effectiveness of cone beam algorithm

Conclusions

Author: ImPACT

E-mail: impact@impactscan.org

Homepage: http://www.impactscan.org/

ImPACT course presentation index: http://www.impactscan.org/impactcourseslides.htm