Magnetization transfer from inhomogeneously broadened lines (ihMT): Experimental optimization of saturation parameters for human brain imaging at 1.5 Tesla. Issue 6 (24th June 2014)

• Record Type: Journal Article
• Authors: Girard, Olivier M.; Prevost, Valentin H.; Varma, Gopal; Cozzone, Patrick J.; Alsop, David C.; Duhamel, Guillaume
• Is Part Of: Magnetic resonance in medicine. Volume 73:Issue 6(2015:Jun.)
• Page Start: 2111
• Page End: 2121
• Publication Date: 2014-06-24
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25330
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm25330-sec-1001" sec-type="section"> <title>Purpose</title> <p>Recently a new MR endogenous contrast mechanism was reported. It allows specifically imaging the magnetization transfer (MT) effect arising from inhomogeneously broadened components of the NMR spectrum, and was hence dubbed ihMT. Such unique NMR lineshape properties are presumably occurring in myelin because of its specifically ordered, multilayered sheath structure. Here, optimization of a pulsed ihMT preparation module is presented to provide guidance for future studies and improve the understanding of underlying contrast mechanisms.</p> </sec> <sec id="mrm25330-sec-2001" sec-type="section"> <title>Methods</title> <p>This study was performed at 1.5 Tesla on healthy volunteers. A pulsed ihMT preparation was implemented in combination with a HASTE readout module. The pulse width, interpulse repetition time, total saturation duration and RF saturation power were considered for optimization of the ihMT sensitivity and contrast.</p> </sec> <sec id="mrm25330-sec-3001" sec-type="section"> <title>Results</title> <p>An optimal configuration of the preparation module was derived, leading to 10% ihMT signal in internal capsule (relative to unsaturated data) and around 200% signal increase relative to gray matter, i.e., approximately 10‐fold superior contrast compared with conventional MT ratios, measured under similar experimental conditions.</p> </sec> <sec id="mrm25330-sec-4001" sec-type="section"> <title>Conclusion</title> <p>Overall the ihMT sequence was robust, sensitive and very specific for white matter. These findings suggest great potential for assessing brain myelination and for better characterization of myelin related disorders. Magn Reson Med 73:2111–2121, 2015. © 2014 Wiley Periodicals, Inc.</p> </sec> </abstract>