Asymmetric spin echo sequences. a simple new method for obtaining NMR 1H spectral images

Update Item Information
Publication Type Journal Article
School or College College of Science
Department Physics
Creator Ailion, David Charles; Morris, Alan H.
Other Author Blatter, Duane D.; Case, Thomas A.
Title Asymmetric spin echo sequences. a simple new method for obtaining NMR 1H spectral images
Date 1985
Description The nuclear magnetic resonance (NMR) signal decay produced by reversible tissue-induced dephasing of the magnetization components in the transverse plane (reversible tissue-induced dephasing) was measured and expressed as a function of a new transverse relaxation time T'2 (T2 prime) for samples of rat liver, retroperitoneal fat, inflated lung, and corn oil. Simple exponentials did not adequately describe the observed NMR signal decay. Inflated lung demonstrated the most rapid signal decay (T'2 = 4.8 ms) followed by retroperitoneal fat (T'2 = 16 ms). No reversible tissue-induced dephasing was observed in liver (T'2 immeasurably long). In tissues which contain both fat and water, the chemically shifted 'H resonance peaks from -OH and -CH- are in phase with symmetric spin echo sequences but out of phase with asymmetric sequences. The interference of these two peaks produces a beat pattern with asymmetric sequences. Subtraction images obtained from paired symmetric- and asymmetric-sequence images accurately (r = .96) reflect T'2 and can be used to indicate the presence of fat. In vivo subtraction images of ethionine-induced fatty rat livers were significantly different from similar in vivo images of normal rat livers (P<.0005). Since for each pixel of a subtraction image, the magnitude of the difference signal should be approximately proportional to the ratio of hydroxyl and alkyl protons, this simple spin echo sequence modification may obviate the need for more timeconsuming 3-dimensional Fourier transform proton chemical shift images.
Type Text
Publisher Wolters Kluwer (LWW)
Volume 20
Issue 8
First Page 845
Last Page 853
Subject Asymmetric spin echo; Signal decay; Chemical shift; Tissue characterization; Lung aeration; Fatty liver
Subject LCSH Nuclear magnetic resonance; Lungs -- Physiology; Liver -- Physiology
Language eng
Bibliographic Citation Blatter, D. D., Morris, A. H., Ailion, D. C., Cutillo, A. G., & Case, T. A. (1985). Asymmetric spin echo sequences. a simple new method for obtaining NMR 1H spectral images. Investigative Radiology, 20(8), 845-53.
Rights Management (c) Wolters Kluwer (LWW)
Format Medium application/pdf
Format Extent 791,737 bytes
Identifier ir-main,10932
ARK ark:/87278/s6kw6092
Setname ir_uspace
ID 703758
Reference URL https://collections.lib.utah.edu/ark:/87278/s6kw6092