𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Correction of B1 inhomogeneities using echo-planar imaging of water

✍ Scribed by Keith R. Thulborn; Fernando E. Boada; Gary X. Shen; James D. Christensen; Timothy G. Reese

Book ID
102957521
Publisher
John Wiley and Sons
Year
1998
Tongue
English
Weight
866 KB
Volume
39
Category
Article
ISSN
0740-3194

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✦ Synopsis

Abstract

Reliable interpretation of the MR signal intensity over the FOV of an image must consider the spatial heterogeneity of instrumental sensitivity. A major source of such variation is the nonuniformity of the B~1~ magnetic field of the radiofrequency coil. This heterogeneity can be minimized by coil design but is exaggerated by surface coils, which are used to maximize the signal‐to‐noise ratio for some applications. This paper describes a rapid method for mapping the B~1~ field over the sample of interest, using ^1^H echo‐planar imaging, to correct for B~1~ distortions. The method applies to ^1^H imaging and has been extended to non‐^1^H imaging by using dual‐frequency coils in which the B., distributions are matched for the ^1^H frequency and the frequency of interest. The approach is demonstrated in phantoms, animals, and humans and for sodium imaging.

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