A new method for efficiently processing MRS data acquired with phased-array coils is presented. The method consists of performing phase compensation (i.e., redefining the signal phase relative to a common reference) of the signals in the time domain prior to combining the signals. The resulting spectra are equivalent to those obtained by previously published methods for phased-array spectral data processing (i.e., processing the signals individually and then combining them in the frequency domain). The method allows spectra acquired with phased-array coils to be processed as efficiently as those acquired with non-phased-array coils. Both single voxel spectroscopy (SVS) and chemical shift imaging (CSI) data sets may be processed by this method.
HASTE (Half fourier Single-shot Turbo spin-Echo) is a single-section T2-weighted sequence that acquires images in less than 1 second. Images are breathing independent and possess a variety of other features useful for imaging the abdomen. The design of this technique is described. Clinical studies of 38 consecutive patients were performed using this technique. HASTE images were considered good in 28 and fair in 10 patients, including five patients who could not suspend respiration. Definition of liver and bowel was particularly clear.
Sons, 1995. $29.95; pp 149: paperback As stated in the Preface to the first edition of MRI: Basic Principles and Applications, Drs. Brown and Semelka seek to present thr basic concepts ol MRI in a fashion that is comprehensible to a wide range of readers. The authors have successfully met this goal by combining a mixture of well-written text, supporting images, and a few equations where necessary to support the fundamental concepts of MFX A highlight is the use of images to support many fundamental concepts. This frequently allows the authors to avoid the use of unnecessary depth in physics, which would be inappropriate for clinical scientists.The book is organized inLo five sections: basic NMR/MIU physics, spatial localization and imaging techniques, more elaborate imaging techniques and contrast mechanisms, hardware, and finally contrast agents. Each section is further subdillded into a small number of chapters that facilitate the dissection of the complexities into manageable pieces. The chapters are, in general, succinct and present the material in an approachable manner appropriate to those with a limited mathematical background. The authors are to be commended on meeting their goal of simplifylng a number of difficult topics and reducing them to this largely nonmathematical foundation.The book's coverage of pulse sequences begins with standard spin-echo, inversion-recovery, and gradient-echo methods, and leads eventually to magnctization preparation and echo-planar imaging. Methods such as spatial presaturation, magnetization transfer, and fat suppression are dealt with as separate topics and described in the context of Additional Measurement Techniques. The separation of these as supplemental methods to be combined with traditional techniques is both appropriate and well executed. In the case of magnetization transfer, however, only a minor description is employed and no images in support of the concepts are provided, which is unfortunate considering MTs applicability in MRA and post-contrast-agent imaging.The book, in its entirety, is comprehensive at a superficial level and moves rapidly from topic to topic. Within an easy three evening reading, it provides a full-gamut description of MRI. While the text provides essentially nothing new, and duplicates material that can be found elsewhere, it does so in a concise manner. This condensation provides a single source for easy recall, which wdl make it a useful addition to many. However, a detailed reference list within each chapter would be useful in directing those interested to more complete material on the topics presented.While the book has several strengths, a few minor criticisms are appropriate. In the basic physics section, the Boltzman distribution is presented and summarized as an excess of 1:106 protons in the lower energy state. Unfortunately, this is true only at a single, unstated field strength, temperature [assumed body temperature), and volume, and hereby prevents the authors from demonstrating its vanability, for example, with field st...
Summary:The word length effect, the finding that words that have fewer syllables are recalled better than otherwise comparable words that have more syllables, is one of the benchmark effects that must be accounted for in any model of serial recall, and simulation models of immediate memory rely heavily on the finding. However, previous research has shown that the effect disappears when participants are asked to recall the items in strict backward order.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.