Accelerated five‐dimensional echo planar J‐resolved spectroscopic imaging: Implementation and pilot validation in human brain. Issue 1 (19th January 2015)

• Record Type: Journal Article
• Authors: Wilson, Neil E.; Iqbal, Zohaib; Burns, Brian L.; Keller, Margaret; Thomas, M. Albert
• Is Part Of: Magnetic resonance in medicine. Volume 75:Issue 1(2016:Jan.)
• Page Start: 42
• Page End: 51
• Publication Date: 2015-01-19
• Subjects: echo‐planar J‐resolved spectroscopic imaging -- compressed sensing -- nonuniform sampling -- J‐resolved spectroscopic imaging -- human brain -- 3D spectroscopic imaging; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25605
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: To implement an accelerated five‐dimensional (5D) echo‐planar J‐resolved spectroscopic imaging sequence combining 3 spatial and 2 spectral encoding dimensions and to apply the sequence in human brain. Methods: An echo planar readout was used to acquire a single spatial and a single spectral dimension during one readout. Nonuniform sampling was applied to the two phase‐encoded spatial directions and the indirect spectral dimension. Nonlinear reconstruction was used to minimize the ℓ 1 ‐norm or the total variation and included a spectral mask to enhance sparsity. Retrospective reconstructions at multiple undersamplings were performed in phantom. Ten healthy volunteers were scanned with 8× undersampling and compared to a fully sampled single slice scan. Results: Retrospective reconstruction of fully sampled phantom data showed excellent quality at 4×, 8×, 12×, and 16× undersampling using either reconstruction method. Reconstruction of prospectively acquired in vivo scans with 8× undersampling showed excellent quality in the occipito‐parietal lobes and good quality in the frontal lobe, consistent with the fully sampled single slice scan. Conclusion: By utilizing nonuniform sampling with nonlinear reconstruction, 2D J ‐resolved spectra can be acquired over a 3D spatial volume with a total scan time of 20 min, which is reasonable for in vivo studies. Magn Reson Med 75:42–51, 2016. © 2015 Wiley Periodicals, Inc.