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Signal-to-noise in phase angle reconstruction: dynamic range extension using phase reference offsets.

T E Conturo·G D Smith
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Abstract

The dynamic range of phase-reconstructed magnetic resonance images is compared to that of magnitude-reconstructed images. From analysis of propagation of errors, the phase angle noise is phase-independent and given in radians by sigma ([I])/[I], the noise-to-signal ratio of the corresponding magnitude-reconstructed image. As the phase can range from minus pi to pi, the phase angle dynamic range is 2 pi times that of the signal magnitude. These results agree with experiment, verifying that the noise in the two receiver channels is uncorrelated. An artifact-free technique is presented for correcting phase spillover, which further extends the phase angle dynamic range. The reconstruction-based reference phase is adjusted on a local basis so that the boundary of phase wraparound is reconstructed near the center of the [- pi, pi] interval. For a particular flow study, the phase signal-to-noise was extended over twofold by spillover correction, to a value 15 times that of the magnitude signal-to-noise.

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AlgorithmsHumansImage Processing, Computer-AssistedMagnetic Resonance ImagingModels, StructuralPortal SystemJournal ArticleResearch Support, U.S. Gov't, P.H.S.

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BibTeXRIS

T E Conturo, G D Smith. 1990. Signal-to-noise in phase angle reconstruction: dynamic range extension using phase reference offsets.. https://doi.org/10.1002/mrm.1910150308

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