RADIO-FREQUENCY FIELD INTENSITY MAPPING USING A COMPOSITE SPIN-ECHO SEQUENCE

被引：31

作者：

OH, CH

HILAL, SK

CHO, ZH

MUN, IK

机构：

[1] Department of Radiology, Columbia University, New York

[2] Department of Radiological Sciences, University of California, Irvine, CA

[3] Department of Electrical Science, KAIS, Seoul

来源：

MAGNETIC RESONANCE IMAGING | 1990年 / 8卷 / 01期

关键词：

Composite RF pulse; MRI; Phase map; RF field map;

D O I：

10.1016/0730-725X(90)90207-I

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：

A novel radio frequency (RF) field intensity mapping or imaging method using a composite NMR spin-echo sequence is proposed. A composite spin-echo RF pulse with 90°y-180°x-90°y sequence makes phase change in the final image depending on the RF field intensity on the object. The resultant phase change or phase map can be used to obtain the actual RF flip-angle map for a given condition which includes the status of tuning and RF inhomogeneity, etc. Bloch equation has been solved numerically to obtain the effects of the RF field intensity as well as the main magnetic field inhomogeneity and the results are used for the mapping (imaging) of the RF field intensity. Phantom studies have been performed using a 1.5 Tesla whole body MRI system and the results are presented. © 1990.

引用

页码：21 / 25

页数：5

共 8 条

[1]

Lauterbur, Image formation by induced local interactions: Examples employing nuclear magnetic resonance, Nature, 242, (1973)

[2]

Cho, Kim, Song, Cumming, Fourier transform nuclear magnetic resonance tomographic imaging, Proc. IEEE, 70, (1982)

[3]

Murphy-Boesh, So, James, Precision mapping of B1 field profiles using the rotating frame experiment, Proc. SMRM, 5, pp. 1069-1070, (1986)

[4]

Hornak, Szumowski, Bryant, Magnetic field mapping, Magn. Reson. Med., 6, pp. 158-163, (1988)

[5]

Levitt, Composite pulses, Progress NMR Spectroscopy, 18, pp. 61-122, (1986)

[6]

Cho, Oh, Kim, Mun, Nalcioglu, Lee, Jung, A new nuclear magnetic resonance imaging technique for unambigous unidirectional measurement of flow velocity, J. Appl. Phys., 60, pp. 1256-1262, (1986)

[7]

Oh, Cho, A new phase coding method using a slice selection gradient for high speed flow velocity measurement in NMR tomography, Phys. Med. Biol., 31, pp. 1237-1246, (1986)

[8]

Cho, Park, Ra, Hilal, Chemical shift artifact correction scheme using echo time encoding technique, Magn. Reson. Med., 2, pp. 253-261, (1985)

← 1 →