Cardiac imaging at 7 tesla: Single- and two-spoke radiofrequency pulse design with 16-channel parallel excitation

58Citations
Citations of this article
55Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

Purpose Higher signal to noise ratio (SNR) and improved contrast have been demonstrated at ultra-high magnetic fields (≥7 Tesla [T]) in multiple targets, often with multi-channel transmit methods to address the deleterious impact on tissue contrast due to spatial variations in B1+ profiles. When imaging the heart at 7T, however, respiratory and cardiac motion, as well as B0 inhomogeneity, greatly increase the methodological challenge. In this study we compare two-spoke parallel transmit (pTX) RF pulses with static B1+ shimming in cardiac imaging at 7T. Methods Using a 16-channel pTX system, slice-selective two-spoke pTX pulses and static B1+ shimming were applied in cardiac CINE imaging. B1+ and B0 mapping required modified cardiac triggered sequences. Excitation homogeneity and RF energy were compared in different imaging orientations. Results Two-spoke pulses provide higher excitation homogeneity than B1+ shimming, especially in the more challenging posterior region of the heart. The peak value of channel-wise RF energy was reduced, allowing for a higher flip angle, hence increased tissue contrast. Image quality with two-spoke excitation proved to be stable throughout the entire cardiac cycle. Conclusion Two-spoke pTX excitation has been successfully demonstrated in the human heart at 7T, with improved image quality and reduced RF pulse energy when compared with B1+ shimming. Magn Reson Med 70:1210-1219, 2013. © 2013 Wiley Periodicals, Inc. Copyright © 2013 Wiley Periodicals, Inc.

References Powered by Scopus

Actual flip-angle imaging in the pulsed steady state: A method for rapid three-dimensional mapping of the transmitted radiofrequency field

849Citations
N/AReaders
Get full text

7T vs. 4T: RF power, homogeneity, and signal-to-noise comparison in head images

742Citations
N/AReaders
Get full text

Transmit SENSE

648Citations
N/AReaders
Get full text

Cited by Powered by Scopus

Pros and cons of ultra-high-field MRI/MRS for human application

375Citations
N/AReaders
Get full text

Parallel transmission for ultrahigh-field imaging

158Citations
N/AReaders
Get full text

MRI at 7 Tesla and above: Demonstrated and potential capabilities

153Citations
N/AReaders
Get full text

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Cite

CITATION STYLE

APA

Schmitter, S., Delabarre, L., Wu, X., Greiser, A., Wang, D., Auerbach, E. J., … Van De Moortele, P. F. (2013). Cardiac imaging at 7 tesla: Single- and two-spoke radiofrequency pulse design with 16-channel parallel excitation. Magnetic Resonance in Medicine, 70(5), 1210–1219. https://doi.org/10.1002/mrm.24935

Readers' Seniority

Tooltip

PhD / Post grad / Masters / Doc 24

56%

Researcher 11

26%

Lecturer / Post doc 5

12%

Professor / Associate Prof. 3

7%

Readers' Discipline

Tooltip

Engineering 19

50%

Physics and Astronomy 9

24%

Medicine and Dentistry 9

24%

Neuroscience 1

3%

Save time finding and organizing research with Mendeley

Sign up for free