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Type:
Educational Exhibit
Keywords:
Artifacts, Diagnostic procedure, MR, MR physics
Authors:
A. Cassarà1, G. Fini1, T. Bongiovanni1, F. Cartabbia1, E. Soligo1, M. Abruzzese1, L. Y. Samman1, A. Stecco1, A. Carriero2; 1NOVARA/IT, 2Novara (NO)/IT
DOI:
10.1594/ecr2017/C-1089
Background
An artifact in MRI is configured as a result of distortion / alteration of the image that causes an image representation that does not correspond to reality. It is a finding inside the images not normally anatomically present,
but visible due to limitation / malfunction in hardware / software,
extrinsic (heat or humidity environment) or intrinsic (pulsation,
breathing,
implants) factors.
The knowledge of the artifacts and the factors that produce noise is important to obtain high quality images.
From this the idea to classify,
describe and find one or more solutions to artifacts that frequently can jeopardize the attainment of a proper MRI examination.
Some artifacts are avoidable,
others may also be exploited for diagnostic purposes.
The artifacts in this discussion were divided into three categories: tissue,
motion and technique related.
Tissue related:
- Chemical-Shift
- FID Signal
- Field Inhomogeneity
- Gibbs
- Magic angle
- Magnetic Susceptivity
- Moirè fringes
- Partial Volume
- Gadolinium hyperconcentration
Motion related
- Ghost
- Smear
Technique related:
1.
Scan technique
2.
Interpherences
- RF Noise
- RF inhomogeneity
- Eddy current
3.
Hardware & Software
- Central point
- Crisscross
- Entry slice
- Nyquist N/2
- Zipper
- Receiver ignition
- Hardware errors
- Data corruption
- Analogic-digital converter block
Artifacts may be very obvious or confined to a few pixels and can mislead the diagnosis,
hence the need to apply countermeasures.