Non‐spin‐echo 3D transverse hadamard encoded proton spectroscopic imaging in the human brain. Issue 1 (24th August 2012)

• Record Type: Journal Article
• Authors: Cohen, Ouri; Tal, Assaf; Goelman, Gadi; Gonen, Oded
• Is Part Of: Magnetic resonance in medicine. Volume 70:Issue 1(2013:Jul.)
• Page Start: 7
• Page End: 15
• Publication Date: 2012-08-24
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.24464
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A non‐spin‐echo multivoxel proton MR localization method based on three‐dimensional transverse Hadamard spectroscopic imaging is introduced and demonstrated in a phantom and the human brain. Spatial encoding is achieved with three selective 90° radiofrequency pulses along perpendicular axes: The first two create a longitudinal ±<bold>M<sub>Z</sub></bold> Hadamard order in the volume of interest. The third pulse spatially Hadamard‐encodes the ±<bold>M<sub>Z</sub></bold>s in the volume of interest in the third direction while bringing them to the transverse plane to be acquired immediately. The approaching‐ideal point spread function of Hadamard encoding and very short acquisition delay yield signal‐to‐noise‐ratios of 20 ± 8, 23 ± 9, and 31 ± 10 for choline, creatine, and <italic>N</italic>‐acetylaspartate in the human brain at 1.5 T from 1 cm<sup>3</sup> voxels in 21 min. The advantages of transverse Hadamard spectroscopic imaging are that unlike gradient (Fourier) phase‐encoding: (i) the volume of interest does not need to be smaller than the field of view to prevent aliasing; (ii) the number of partitions in each direction can be small, 8, 4, or even 2 at no cost in point spread function; (iii) the volume of interest does not have to be contiguous; and (iv) the voxel profile depends on the available <bold>B<sub>1</sub></bold> and pulse synthesis paradigm and can, therefore, at least theoretically, approach "ideal" "1" inside and "0" elsewhere. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.</p> </abstract>