Automated shimming at 1.5 T using echo-planar image frequency maps

被引：97

作者：

Reese, TG

Davis, TL

Weisskoff, RM

机构：

[1] Department of Radiology, Massachusetts General Hospital, NMR Center, Charlestown, Massachusetts, 02129

[2] Department of Radiology, Massachusetts General Hospital, NMR Center, Charlestown, Massachusetts, 02129

[3] Department of Radiology, Massachusetts General Hospital, NMR Center, Charlestown, Massachusetts, 02129

来源：

JMRI-JOURNAL OF MAGNETIC RESONANCE IMAGING | 1995年 / 5卷 / 06期

关键词：

MR imaging; image artifacts; MR; shimming; pulse sequences;

D O I：

10.1002/jmri.1880050621

中图分类号：

R8 [特种医学]; R445 [影像诊断学];

学科分类号：

1002 ; 100207 ; 1009 ;

摘要：

Using echo-planar imaging, we developed an automated image-based procedure to shim the static (B-o) field. Our method uses the rapid acquisition capability of echo-planar imaging to collect the required frequency data rapidly, rendering the shim data acquisition time negligible in comparison with the total study time. We address image distortion issues involved in echo-planar imaging acquisition of the data and formulate analytic methods for arriving at an optimal shim for the NMR imaging experiment in a single iteration, We investigated the use of cost functions other than least-squares (Chebychev, high-order numeric) and found that choice between the cost functions we tested was irrelevant to resultant image quality, at least when used in conjunction with low-order shims, With appropriate integration, the method has become routine practice for investigators at our laboratory.

引用

页码：739 / 745

页数：7

共 26 条

[1] Prammer MG, Hasselgrove JC, Shinnar M, Leigh JS, A new approach to automatic shimming, J Magn Reson, 77, pp. 40-52, (1988)
[2] Schneider E, Glover G, Rapid in vivo proton shimming, Magn Reson Med, 18, pp. 335-347, (1991)
[3] Webb P, Macovski A, Rapid, fully automatic, arbitrary volume in vivo shimming, Magn Reson Med, 20, pp. 113-122, (1991)
[4] Gruetter R, Boesch C, Fast, noniterative shimming of spatially localized signals: in vivo analysis of the magnetic field along axes, J Magn Reson, 96, pp. 323-334, (1992)
[5] Hu J, Willard T, Srinivasan R, Stoyanova R, Murphy-Boesch J, Brown TR, Integration of automatic shimming with clinical spectroscopy (abstr), Book of Abstracts: Society of Magnetic Resonance in Medicine 1992, (1992)
[6] Sepponen R, Sipponen J, Tantu J, A method for chemical shift imaging: demonstration of bone marrow involvement with proton CSI, J Comput Assist Tomogr, 8, pp. 585-587, (1984)
[7] Dixon W, Simple proton spectroscopic imaging, Radiology, 153, pp. 189-194, (1984)
[8] Hoppel B, Weisskoff R, Thulborn K, Moore J, Kwong K, Rosen B, Measurement of regional blood oxygenation and cerebral hemodynamics, Magn Reson Med, 30, pp. 715-723, (1993)
[9] Sekihara K, Kuroda M, Kohno H, Image restoration from non‐uniform magnetic field influence for direct fourier NMR imaging, Phys Med Biol, 29, pp. 15-24, (1984)
[10] Sekihara K, Kohno H, Image restoration from non‐uniform static field influence in modified echo‐planar imaging, Med Phys, 14, pp. 1087-1089, (1987)

← 1 2 3 →