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Frequency difference mapping applied to the corpus callosum at 7T

Tendler, Benjamin C.; Bowtell, Richard

Frequency difference mapping applied to the corpus callosum at 7T Thumbnail


Benjamin C. Tendler


Purpose: Frequency difference mapping (FDM) is a phase processing technique which characterises the non-linear temporal evolution of the phase of gradient echo signals. Here, a novel FDM processing algorithm is introduced, which is shown to reveal information about white matter microstructure. Unlike some other phase processing techniques, the FDM algorithm presented here does not require the use of phase unwrapping or sophisticated image processing. It uses a series of scaled complex divisions to unwrap phase and remove background fields.

Methods: 10 healthy subjects underwent a series of single-slice, sagittal multi-echo gradient echo scans at 7T with the slice positioned at the mid-line. Phase data were processed with the novel FDM algorithm and the temporal evolution of the magnitude signal and frequency difference was examined in 5 regions of the corpus callosum (genu, anterior body, middle body, posterior body and splenium).

Results: Consistent frequency difference contrast relative to surrounding tissue was observed in all subjects in the corpus callosum, and in other white matter regions where the nerves fibres run perpendicular to 𝐵0, such as the superior cerebellar peduncle. Examination of the frequency difference curves shows distinct variations over the corpus callosum, with the genu and splenium displaying larger frequency differences than the other regions (in addition to a faster decay of the signal magnitude).

Conclusion: The novel FDM algorithm presented here yields images sensitive to tissue microstructure and microstructural differences over the corpus callosum in a simple manner, without the requirement for phase unwrapping or sophisticated image processing.


Tendler, B. C., & Bowtell, R. (2019). Frequency difference mapping applied to the corpus callosum at 7T. Magnetic Resonance in Medicine, 81(5), 3017-3031.

Journal Article Type Article
Acceptance Date Nov 14, 2018
Online Publication Date Dec 23, 2018
Publication Date 2019-05
Deposit Date Nov 16, 2018
Publicly Available Date Dec 23, 2018
Journal Magnetic Resonance in Medicine
Print ISSN 0740-3194
Electronic ISSN 1522-2594
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 81
Issue 5
Pages 3017-3031
Keywords Radiology Nuclear Medicine and imaging
Public URL
Publisher URL


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