The performance of the rotating frame localization method is discussed, with emphasis on performing the experiment and processing the data in the optimum manner. Studies on phantom samples are presented to illustrate various imperfections which affect the confidence that can be placed on acquired da
MR spectroscopy using multi-ring surface coils
β Scribed by Scott B. King; Lawrence N. Ryner; Boguslaw Tomanek; Jonathan C. Sharp; Ian C.P. Smith
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 208 KB
- Volume
- 42
- Category
- Article
- ISSN
- 0740-3194
No coin nor oath required. For personal study only.
β¦ Synopsis
A spatially uniform B 1 -field is preferred for MR imaging and spectroscopy. Unfortunately, volume coils are sometimes unavailable, or do not provide adequate RF power or SNR for some applications. In quantitative MRS, mean metabolite concentration cannot be evaluated when the coil response is nonuniform, unless an assumption is made concerning the metabolite spatial distribution. It is well known that standard single-loop surface coils, although offering high SNR characteristics, have poor B 1 homogeneity. New multi-ring surface coils are proposed which produce a locally uniform B 1 field, with sensitivity and power requirements comparable to those of standard surface coils. MR spectroscopy using two and three-ring versions of this ''local volume coil'' result in spatial localization essentially identical to that obtained with a volume coil but with much improved RF power and SNR characteristics. When compared to standard surface coils, the multi-ring coil offers much improved water suppression and localization, as well as reduced outer voxel contamination, with only a small loss in SNR and moderate increase in SAR. In summary, the multi-ring coil operates midway between the volume coil and the standard surface coil, retaining the most advantageous properties of both.
π SIMILAR VOLUMES
## Abstract A new method for efficiently processing MRS data acquired with phasedβarray 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 r
MR microscopy on intact rats using a single surface coil is reported. The use of the same coil for excitation and detection is experimentally very simple and results in a smaller field-of-view than the conventional setup using homogeneous excitation (whole-body coil or a large surface coil) and a sm
## Abstract ## Purpose To establish a fast and highβresolution MR sialographic technique that provides fast and highβresolution imaging. ## Materials and Methods MR sialography was performed on a 1.5βT MR imager using a small (47βmm) surface coil. We determined appropriate sequence parameters, a