An image artifact is a structure not normally present but visible as a result of a limitation or malfunction in the
hardware or software of the
MRI device, or in other cases a consequence of environmental influences as heat or humidity or it can be caused by the human body (blood
flow,
implants etc.). The knowledge of
MRI artifacts (brit. artefacts) and
noise producing factors is important for continuing maintenance of high
image quality. Artifacts may be very noticeable or just a few pixels out of balance but can give confusing artifactual appearances with pathology that may be misdiagnosed.
Changes in patient position, different pulse
sequences, metallic artifacts, or other imaging variables can cause image distortions, which can be reduced by the operator; artifacts due to the
MR system may require a service engineer.
Many types of artifacts may occur in
magnetic resonance imaging. Artifacts in
magnetic resonance imaging are typically classified as to their basic principles, e.g.:
•
Physiologic (motion,
flow)
•
Hardware (electromagnetic spikes, ringing)
Several techniques are developed to reduce these artifacts (e.g.
respiratory compensation,
cardiac gating,
eddy current compensation) but sometimes these effects can also be exploited, e.g. for
flow measurements.
See also the related poll result: '
Most outages of your scanning system are caused by failure of'
•
] and 3 definitions [
]
Further Reading:
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