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Ultimate Intrinsic SNR in a Uniform Sphere

MATLAB code for determining the UISNR at the center of a dielectric sphere.

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We are making available a MATLAB script for calculating the ultimate intrinsic signal-to-noise ratio (UISNR) at the center of a uniform dielectric sphere. The algorithm determines the UISNR analytically, without the need for complex simulations.

Rapid and direct calculation of the UISNR may serve as an absolute reference for performance assessments of head coils with spherical phantoms. The MATLAB script provides all functions necessary to perform the calculations. The package also includes a simple PDF guide that explains how to estimate the scaling factor for comparisons between experimentally measured SNR and the UISNR calculated by this code.

A snapshot of ideal current patterns associated with ultimate intrinsic signal-to-noise ratio (UISNR) at the center of a sphere at various B0 field strengths, from left: 1.5 T, 3 T, 7 T, and 11 T.
A snapshot of ideal current patterns associated with ultimate intrinsic signal-to-noise ratio (UISNR) at the center of a sphere at various B0 field strengths, from left: 1.5 T, 3 T, 7 T, and 11 T. The two-dimensional views in the bottom row show that the current patterns are identical, except for varying phase shift. For more information, see the related publications, below.

Related Publications

Lee HH, Sodickson DK, Lattanzi R.
An analytic expression for the ultimate intrinsic SNR in a uniform sphere.
Magn Reson Med. 2018 Nov;80(5):2256-2266. doi: 10.1002/mrm.27207

Lee HH, Sodickson DK, Lattanzi R.
An analytic expression for the ultimate intrinsic SNR in a uniform sphere.
Proc Intl Soc Mag Reson Med. 25(2017). doi: p 4294

Please cite these works if you are using UISNR in a uniform sphere in your research.

Get the Code

The software available on this page is provided free of charge and comes without any warranty. CAI²R and NYU Grossman School of Medicine do not take any liability for problems or damage of any kind resulting from the use of the files provided. Operation of the software is solely at the user’s own risk. The software developments provided are not medical products and must not be used for making diagnostic decisions.

The software is provided for non-commercial, academic use only. Usage or distribution of the software for commercial purpose is prohibited. All rights belong to the author (Hong Hsi Lee) and NYU Grossman School of Medicine. If you use the software for academic work, please give credit to the author in publications and cite the related publications.

Please spell out your affiliation (e.g. “New York University” rather than “NYU”).

Contact

Questions about this resource may be directed to Riccardo Lattanzi, PhD or Hong-Hsi Lee, PhD at hlee84@mgh.harvard.edu.