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MRI Forum: Geometric distortion
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  Category:  Artifacts
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ergun ahunbay

Tue. 2 Jan.07,
19:20
Geometric distortion
Dear Listers,

I have some questions about the image distortions in MRI:

1) Are the magnetic field inhomogeneities the only cause of image distortions? Does RF-inhomogeneities cause distortions or just signal inaccuracies?

2) Is it accurate to say that a spiral sequence would not have distortion due to magnetic field inhomogeneity(, but it would have blurring). Would there be image geometric distortions with a spiral imaging?

thank you very much in advance

peter hobden

Wed. 14 Feb.07,
15:35
Dear Listers,

I have some questions about the image distortions in MRI:

1) Are the magnetic field inhomogeneities the only cause of image distortions? Does RF-inhomogeneities cause distortions or just signal inaccuracies?

There are other factors that can affect the /amount/ of distortion. Run an EPI sequence and change the bandwidth and see the image change shape.

There are other causes of image distortion which are not necessarily directly related to field homogeneity.

It is a complicated question you are asking here!


2) Is it accurate to say that a spiral sequence would not have distortion due to magnetic field inhomogeneity(, but it would have blurring). Would there be image geometric distortions with a spiral imaging?


I guess you are talking about spiral filling of k-space?? The sampling time reduction will help to reduce distortion to some extent.

John Muller

Fri. 12 Sep.08,
00:02
You can find more information about magnetic field in: http://www.youtube.com/watch?v=evfUTmx0uh8&feature=related

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