Improving T2-weighted imaging at high field through the use of kT-points

Eggenschwiler, Florent, O'Brien, Kieran R., Gruetter, Rolf and Marques, Jose P. (2014) Improving T2-weighted imaging at high field through the use of kT-points. Magnetic Resonance in Medicine, 71 4: 1478-1488. doi:10.1002/mrm.24805


Author Eggenschwiler, Florent
O'Brien, Kieran R.
Gruetter, Rolf
Marques, Jose P.
Title Improving T2-weighted imaging at high field through the use of kT-points
Formatted title
Improving T2-weighted imaging at high field through the use of kT-points
Journal name Magnetic Resonance in Medicine   Check publisher's open access policy
ISSN 1522-2594
0740-3194
Publication date 2014-04
Sub-type Article (original research)
DOI 10.1002/mrm.24805
Open Access Status Not Open Access
Volume 71
Issue 4
Start page 1478
End page 1488
Total pages 11
Place of publication Hoboken, NJ United States
Publisher John Wiley & Sons
Language eng
Formatted abstract
Purpose

At high magnetic field strengths (B0 ≥ 3 T), the shorter radiofrequency wavelength produces an inhomogeneous distribution of the transmit magnetic field. This can lead to variable contrast across the brain which is particularly pronounced in T2-weighted imaging that requires multiple radiofrequency pulses. To obtain T2-weighted images with uniform contrast throughout the whole brain at 7 T, short (2–3 ms) 3D tailored radiofrequency pulses (kT-points) were integrated into a 3D variable flip angle turbo spin echo sequence.

Methods

The excitation and refocusing “hard” pulses of a variable flip angle turbo spin echo sequence were replaced with kT-point pulses. Spatially resolved extended phase graph simulations and in vivo acquisitions at 7 T, utilizing both single channel and parallel-transmit systems, were used to test different kT-point configurations.

Results

Simulations indicated that an extended optimized k-space trajectory ensured a more homogeneous signal throughout images. In vivo experiments showed that high quality T2-weighted brain images with uniform signal and contrast were obtained at 7 T by using the proposed methodology.

Conclusion

This work demonstrates that T2-weighted images devoid of artifacts resulting from B1+ inhomogeneity can be obtained at high field through the optimization of extended kT-point pulses.
Keyword TSE sequence
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Advanced Imaging Publications
 
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