Yield Enhancement of a Double-Quantum Filter Sequence Designed for the Edited Detection of GABA

✍ Scribed by Alan H. Wilman; Peter S. Allen

• Book ID: 102595960
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 146 KB
• Volume: 109
• Category: Article
• ISSN: 1064-1866
• DOI: 10.1006/jmrb.1995.0006

✦ Synopsis

To overcome limitations in the signal to noise ratio (S/N) of (14) were able to increase the GABA/Cr signal ratio by previously proposed multiple-quantum filters (MQFs), designed Ç450, i.e., from 0.03 to 14 in normal brain. However, despite for editing the GABA A 2 multiplet from the creatine (Cr) singlet this highly efficient editing, the long length of this fully in proton spectroscopy of brain, a new double-quantum filter is refocused filter (Ç1/J Å 137 ms) leads to significant transproposed which significantly enhances S/N (thereby making it verse-relaxation losses, which subsequently add to any inhercomparable with the spin-echo difference editing technique) while ent filter losses (intrinsic yield 25%). The principal purpose maintaining the superior Cr suppression and zero vulnerability to of the present paper is to report how appropriately chosen subtraction errors of previously proposed MQFs. The S/N enbut significant reductions in the duration of a double-quanhancement results primarily from a significant reduction in transtum filter (DQF) can be brought about (to Ç 1 4 of the usual verse-relaxation losses, achieved by shortening the filter sequence 1/J). Such reductions provide substantial increases in the by Ç70%, first by altering the criterion that determines the initial evolution period and, second, by effectively eliminating the refo-edited transverse magnetization, and hence in the signalcusing time prior to the start of acquisition. The altered evolution to-noise ratio, without compromising the excellent editing time criterion also leads to an increase in the intrinsic yield of the performance of the DQF. A second advantage of the sefilter from 25 to 39%. The analysis of the filter design was verified quences reported here is that they also increase the intrinsic in vitro on phantoms of GABA in D 2 O, and the maintenance of signal yield of the filter (to 39%), adding further to the editing capability, i.e., Cr suppression by more than 1600, was signal-to-noise improvements. The resulting filtered transdemonstrated on rat brain extracts.