Synopsis
This talk will give a clinically oriented perspective on understanding, using and if desirable, avoiding MR artifacts.Target Audience
Clinicians
(Residents, Fellows, and Attending Level) whose practice includes MRI. Graduate
students studying MR for their research will also benefit from this talk. Advanced
MR researchers may enjoy the talk but are not specifically targeted.
Purpose
·
Understand
what is an MR artifact
·
Learn
to identify key artifacts and to understand their origins
·
Learn
how to eliminate the artifacts, if this is desired
·
Learn
how to utilize artifacts for diagnostic purposes, whenever possible
Description
In MR clinical
practice, we routinely encounter imaging artifacts – that is, features of the
MR image that are not present in the object being imaged. Some artifacts are
encountered routinely, while others are seen under special conditions. We will
try to understand the origin of these artifacts, relating it to the MR signal
acquisition and image reconstruction process, but the approach will be as
non-mathematical as possible, relying instead on figures, cartoons, and actual
images from phantoms and clinical practice. After understanding the artifacts,
we will discuss the next clinical steps after identifying the artifact, namely:
Can the artifact be eliminated or minimized (if this is even desirable) and
how, or can the artifact be utilized for clinical benefit?
It is not possible to
comprehensively discuss every artifact that can be clinically encountered. We
will focus instead on representative artifacts that are either particularly
common clinically, or are instructive such that understanding them provides
insight into the MRI itself. Representative artifacts that are likely to be
covered include aliasing and parallel imaging artifacts, motion and pulsation,
chemical shift, Gibbs ringing, magnetic susceptibility, and high field B1
inhomogeneities. The explanations will draw from review articles and books and
online sources, which have covered this material in the literature.
Acknowledgements
No acknowledgement found.References
1.
M. Graves and D. G. Mitchell, Body MRI Artifacts in Clinical Practice: A
Physicist’s and Radiologist’s Perspective, J.
Magn. Reson. Imag. 2013;38:269–287.
2.
A. Deshmane, V. Gulani, M. Griswold, N. Seiberlich, Parallel MR Imaging, J. Magn. Reson. Imag. 2012;36:55-72.
3.
J. Tsao and V. Gulani, MR Image Reconstruction, in R. Bammer (Editor), MR and CT Perfusion Imaging, Williams
and Wilkins, 2015 (expected release October 2015)
4.
M. A. Griswold, V. Gulani, MRI Physics, Techniques and General Clinical
Artifacts, Ch. 53, in Haaga, J. (Ed.), CT
and MR Imaging of the Whole Body, 5th Edition, Elsevier, 2009.
5.
D. Elstar, MRIquestions.com, Questions and Answers in MRI, 2015.