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MRI-SLICE SELECTION GRADIENT

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MRI-SLICE SELECTION GRADIENT

1. Essentially, the external magnetic field generated by the MR scanner is homogeneous.
2. If a patient lies in a MR scanner, all of the protons in their body will precess at the same Larmor frequency regardless of where they are in the body.
3. To examine a specific slice of the patient we superimpose a second magnetic field known as the slice selecting gradient (SSG).
4. Produced by gradient coils.
5. Once the SSG has been applied, protons will precess at slightly different frequencies depending on where they are in the SSG.
6. Slice thickness is determined by the slope of the gradient: steeper slice selecting gradient = thinner slice.


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REFERENCES

1. Bushberg, J. T. (2012). The essential physics of medical imaging. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. Find it at Amazon
2. Heggie, J. C., Liddell, N. A., & Maher, K. P. (1997). Applied imaging technology. Melbourne: St. Vincents Hospital.

Ⓒ A. Manickam 2018

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