Simultaneous MRI water-fat separation and quantitative susceptibility mapping of carotid artery plaque pre- and post-ultrasmall superparamagnetic iron oxide-uptake.

Autor: Ruetten PPR; Department of Radiology, University of Cambridge, Cambridge, United Kingdom., Cluroe AD; Department of Histopathology, Addenbrooke's Hospital, Histopathology, Cambridge, United Kingdom., Usman A; Department of Radiology, University of Cambridge, Cambridge, United Kingdom., Priest AN; Department of Medical Physics, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom., Gillard JH; Department of Radiology, University of Cambridge, Cambridge, United Kingdom., Graves MJ; Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.
Jazyk: angličtina
Zdroj: Magnetic resonance in medicine [Magn Reson Med] 2020 Aug; Vol. 84 (2), pp. 686-697. Date of Electronic Publication: 2020 Jan 21.
DOI: 10.1002/mrm.28151
Abstrakt: Purpose: Imaging carotid artery plaques to identify features of vulnerability typically requires a multicontrast MRI protocol. The identification of regions of inflammation with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles requires separate pre- and postcontrast scans. We propose a method of joint water-fat separation and quantitative susceptibility mapping (QSM) to aid classification of atherosclerotic plaques and offer a positive contrast mechanism in USPIO-imaging.
Methods: Ten healthy volunteers (3 women and 7 men; aged, 30.7 ± 10.7 years) were imaged at 1.5T to develop an acquisition and postprocessing protocol. Five patients (1 woman and 4 men; mean age, 71 ± 7.5 years) with moderate to severe luminal stenosis were imaged pre- and postadministration of a USPIO contrast agent. We used a multiecho gradient echo acquisition to perform water/fat separation and subsequently QSM. The results were compared with a conventional multicontrast MRI protocol, CT images, and histopathology data.
Results: In the volunteer scans, a multiecho gradient echo acquisition with bipolar readout gradients demonstrated to be a reliable acquisition methodology to produce high-quality susceptibility maps in conjunction with the proposed postprocessing methodology. In the patient study, water/fat separation provided a tool to identify lipid-rich necrotic cores and QSM provided a qualitative and quantitative evaluation of plaque features and positive contrast when evaluating USPIO uptake. Plaque calcification could be identified by strong diamagnetism (-1.27 ± 0.71 ppm), while USPIO uptake demonstrated a strong paramagnetism (1.32 ± 0.61 ppm).
Conclusion: QSM was able to identify multiple plaque features in a single acquisition, providing positive contrast for plaques demonstrating USPIO uptake and negative contrast for calcification.
(© 2020 International Society for Magnetic Resonance in Medicine.)
Databáze: MEDLINE
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