A comparison of phase imaging and quantitative susceptibility mapping in the imaging of multiple sclerosis lesions at ultrahigh field

Cronin, Matthew John and Wharton, Samuel and Al-Radaideh, Ali and Constantinescu, Chris and Evangelou, Nikos and Bowtell, Richard W. and Gowland, Penny A. (2016) A comparison of phase imaging and quantitative susceptibility mapping in the imaging of multiple sclerosis lesions at ultrahigh field. Magnetic Resonance Materials in Physics, Biology and Medicine, 29 (3). pp. 543-557. ISSN 1352-8661

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Abstract

Objective

The aim of this study was to compare the use of high-resolution phase and QSM images acquired at ultra-high field in the investigation of multiple sclerosis (MS) lesions with peripheral rings, and to discuss their usefulness for drawing inferences about underlying tissue composition.

Materials and methods

Thirty-nine Subjects were scanned at 7 T, using 3D T2*-weighted and T1-weighted sequences. Phase images were then unwrapped and filtered, and quantitative susceptibility maps were generated using a thresholded k-space division method. Lesions were compared visually and using a 1D profiling algorithm.

Results

Lesions displaying peripheral rings in the phase images were identified in 10 of the 39 subjects. Dipolar projections were apparent in the phase images outside of the extent of several of these lesions; however, QSM images showed peripheral rings without such projections. These projections appeared ring-like in a small number of phase images where no ring was observed in QSM. 1D profiles of six well-isolated example lesions showed that QSM contrast corresponds more closely to the magnitude images than phase contrast.

Conclusions

Phase images contain dipolar projections, which confounds their use in the investigation of tissue composition in MS lesions. Quantitative susceptibility maps correct these projections, providing insight into the composition of MS lesions showing peripheral rings.

Item Type: Article
Keywords: Magnetic resonance imaging, Multiple sclerosis, White matter, Iron, Myelin
Schools/Departments: University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Medicine > Division of Clinical Neuroscience
University of Nottingham UK Campus > Faculty of Science > School of Physics and Astronomy
Identification Number: https://doi.org/10.1007/s10334-016-0560-5
Depositing User: Gowland, Penny
Date Deposited: 27 Sep 2016 07:44
Last Modified: 29 Sep 2016 04:12
URI: http://eprints.nottingham.ac.uk/id/eprint/37164

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