Anatomical brain imaging at 7T using two‐dimensional GRASE. Issue 5 (17th December 2013)

• Record Type: Journal Article
• Authors: Trampel, Robert; Reimer, Enrico; Huber, Laurentius; Ivanov, Dimo; Heidemann, Robin M.; Schäfer, Andreas; Turner, Robert
• Is Part Of: Magnetic resonance in medicine. Volume 72:Issue 5(2014:Nov.)
• Page Start: 1291
• Page End: 1301
• Publication Date: 2013-12-17
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25047
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm25047-sec-0001" sec-type="section"> <title>Purpose</title> <p>Specific absorption rate is a serious problem at high field strengths, especially for sequences involving many high power radiofrequency pulses, such as turbo spin echo (TSE). GRASE (gradient and spin echo) may overcome this problem by omitting a certain number of refocusing pulses of a TSE sequence, and replacing them with segmented echo‐planar imaging readouts.</p> </sec> <sec id="mrm25047-sec-0002" sec-type="section"> <title>Methods</title> <p>GRASE and TSE were compared using similar sequence parameters at a field strength of 7T. The signal‐to‐noise ratio (SNR) per unit time, contrast, and point spread function (PSF) were determined. High‐resolution human brain images were acquired and the implementation of an inversion recovery preparation for T1 weighting was evaluated.</p> </sec> <sec id="mrm25047-sec-0003" sec-type="section"> <title>Results</title> <p>TSE and GRASE images at 7T showed very similar SNR and contrast. The slightly worse PSF for GRASE is balanced by a significant reduction in scan time or increase in spatial coverage compared with TSE. Furthermore, implementing an additional inversion recovery preparation enables the acquisition of T1‐weighted images with high SNR per unit time.</p> </sec> <sec id="mrm25047-sec-0004" sec-type="section"> <title>Conclusion</title> <p>GRASE is highly suitable for structural scanning at ultra‐high field strengths and is a valid alternative to the commonly used TSE sequence. Magn Reson Med 72:1291–1301, 2014. © 2013 Wiley Periodicals, Inc.</p> </sec> </abstract>