Metal Artefact Reduction

Magnetic resonance imaging relies on a homogenous magnetic field. When we introduce magnetic field variations across the patient with magnetic field gradients, the magnetic field strength relates to position, and is used to encode the MR signal.

But not in the presence of metal.
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Fazed by Phase

The word “phase” has a few uses in MR physics.

Let’s review them.
It can get confusing.

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Fat Suppression

Suppression of fat signal is used in MRI images when the fat signal causes artefacts or otherwise obscures a tissue of interest.

There are a number of fat suppression methods. Which one you choose depends on the pros and cons of each technique. These change with field strength, field-of-view size, whether regional or global fat suppression is required, whether an increase in scan time is acceptable, etc. Additionally, the absolute quality of fat suppression may not motivate the choice of technique; contrast between tissues of interest may be more important. Overall SNR in an image may also be a deciding factor.

Here is a brief summary of fat suppression techniques.

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Got Tesla?

Moving from 1.5T to 3T?

The value of higher field strength for clinical imaging has been indicated in some clinical applications. Research studies are likely to confirm clinical utility of 3.0T vs. 1.5T—studies showing not just signal-to-noise ratio, contrast-to-noise ratio, or even diagnostic sensitivity and specificity—but effects on patient management, and ultimately, effects on patient outcome.

What are the MR physics issues which are relevant when comparing field strengths?

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Diffusion Tensor Imaging Cheat Sheet

Here is a basic summary of what DTI is all about, and what some of those DTI parametric maps represent.

A one-page cheat sheet is at the end.

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