Diffusion weighted imaging with circularly polarized oscillating gradients. Issue 3 (17th March 2014)

• Record Type: Journal Article
• Authors: Lundell, Henrik; Sønderby, Casper Kaae; Dyrby, Tim B.
• Is Part Of: Magnetic resonance in medicine. Volume 73:Issue 3(2015:Mar.)
• Page Start: 1171
• Page End: 1176
• Publication Date: 2014-03-17
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25211
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm25211-sec-0001" sec-type="section"> <title>Purpose</title> <p>The short diffusion time regime provides an interesting probe for tissue microstructure and can be investigated with oscillating gradient spin echo (OGSE) experiments. Several studies report new contrasts in preclinical settings and the first in vivo human experiments have recently been presented. One major hurdle in practical implementation is the low effective diffusion weighting provided at high frequency with limited gradient strength.</p> </sec> <sec id="mrm25211-sec-0002" sec-type="section"> <title>Theory</title> <p>As a solution to the low diffusion weighting of OGSE, circularly polarized OGSE (CP‐OGSE) is introduced. CP‐OGSE gives a twofold increase in diffusion weighting with encoding in a plane rather than in one direction. CP‐OGSE can be used for rotationally invariant acquisitions on anisotropic tissues.</p> </sec> <sec id="mrm25211-sec-0003" sec-type="section"> <title>Methods</title> <p>Experiments with a 4.7 T preclinical scanner on a postmortem monkey brain as well as simulations were performed using conventional OGSE and CP‐OGSE.</p> </sec> <sec id="mrm25211-sec-0004" sec-type="section"> <title>Results</title> <p>Simulations and experiments show that CP‐OGSE provides the same microstructural information as OGSE but provides more robust parameter estimates with limited gradient strength.</p> </sec> <sec id="mrm25211-sec-0005" sec-type="section"> <title>Conclusions</title> <p>CP‐OGSE can be an important contribution for making OGSE imaging more effective in clinical imaging settings with limited gradient strength. Furthermore, the improved diffusion weighting can also be used to expand the investigated frequency range. <bold>Magn Reson Med 73:1171–1176, 2015. © 2014 Wiley Periodicals, Inc.</bold></p> </sec> </abstract>