A high-frequency RF volume coil based on the use of microstrip transmission line (MTL) has been developed for in vivo 1H MR applications on the human head at 4T. This coil is characterized by major advantages: (i) completely distributed coil circuit, (ii) high-quality factor (Q), (iii) simple coil structure, and (iv) better sensitivity and less signal-intensity variation in the MR image of the human head compared with an RF shielded birdcage coil of similar coil size. The proposed MTL volume coil does not require additional RF shielding for preventing Q degradation from radiation losses due to the unique MTL structure; thus, it provides a maximal useable space inside the volume coil when compared with most volume coils available at high fields with the same overall coil size. The intrinsic B1 distribution of the MTL volume coil effectively compensates for the dielectric resonance effect at 4T and improves the signal homogeneity in human head MR images in the transaxial planes. The results of this study demonstrate that the MTL volume coil design provides an efficient and simple solution to RF volume coil design for human MR studies at high fields.
Bibliographical noteFunding Information:
This work was partially supported by NIH Grants NS38070, NS39043, NS41262, EB00329, and P41 RR08079 (a National Research Resource grant from NIH). The authors gratefully acknowledge scientific discussions and technical assistance from Drs. Qing X. Yang, Hao Lei, Xiao-Hong Zhu, and Haiying Liu, and helpful comments from the reviewers.
Copyright 2008 Elsevier B.V., All rights reserved.
- High field
- Human brain
- MR imaging
- MTL volume coil
- Microstrip transmission line
- RF coil