Compressed sensing to accelerate magnetic resonance spectroscopic imaging: evaluation and application to 23Na-imaging of mouse hearts

Journal of Cardiovascular Magnetic Resonance

Research

Mahon L. Maguire¹  Craig A. Lygate¹  Jürgen E. Schneider¹  Sairam Geethanath²  Vikram D. Kodibagkar³ 

[1] British Heart Foundation Experimental Magnetic Resonance Unit, Radcliffe Department of Medicine – Division of Cardiovascular Medicine, University of Oxford, Roosevelt Drive, OX3 7BN, Oxford, UK;Medical Imaging Research Centre, Dayananda Sagar College of Engineering, 560078, Bangalore, India;School of Biological and Health Systems Engineering, Arizona State University, 85287-9709, Tempe, AZ, USA;

关键词: Compressed sensing;    Magnetic resonance spectroscopic imaging;    Chemical shift imaging;    Mouse;    Sodium;   

DOI  :  10.1186/s12968-015-0149-6

 received in 2014-11-18, accepted in 2015-05-15,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundMagnetic Resonance Spectroscopic Imaging (MRSI) has wide applicability for non-invasive biochemical assessment in clinical and pre-clinical applications but suffers from long scan times. Compressed sensing (CS) has been successfully applied to clinical 1H MRSI, however a detailed evaluation of CS for conventional chemical shift imaging is lacking. Here we evaluate the performance of CS accelerated MRSI, and specifically apply it to accelerate 23Na-MRSI on mouse hearts in vivo at 9.4 T.MethodsSynthetic phantom data representing a simplified section across a mouse thorax were used to evaluate the fidelity of the CS reconstruction for varying levels of under-sampling, resolution and signal-to-noise ratios (SNR). The amplitude of signals arising from within a compartment, and signal contamination arising from outside the compartment relative to noise-free Fourier-transformed (FT) data were determined. Simulation results were subsequently verified experimentally in phantoms and in three mouse hearts in vivo.ResultsCS reconstructed MRSI data are scaled linearly relative to absolute signal intensities from the fully-sampled FT reconstructed case (R2 > 0.8, p-value < 0.001). Higher acceleration factors resulted in a denoising of the reconstructed spectra, but also in an increased blurring of compartment boundaries, particularly at lower spatial resolutions. Increasing resolution and SNR decreased cross-compartment contamination and yielded signal amplitudes closer to the FT data. Proof-of-concept high-resolution, 3-fold accelerated 23Na-amplitude maps of murine myocardium could be obtained within ~23 mins.ConclusionsRelative signal amplitudes (i.e. metabolite ratios) and absolute quantification of metabolite concentrations can be accurately determined with up to 5-fold under-sampled, CS-reconstructed MRSI. Although this work focused on murine cardiac 23Na-MRSI, the results are equally applicable to other nuclei and tissues (e.g. 1H MRSI in brain). Significant reduction in MRSI scan time will reduce the burden on the subject, increase scanner throughput, and may open new avenues for (pre-) clinical metabolic studies.

【 授权许可】

Unknown   
© Maguire et al. 2015. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.