A 32-channel parallel transmit system add-on for 7T MRI

Stephan Orzada; Klaus Solbach; Marcel Gratz; Sascha Brunheim; Thomas M Fiedler; Sören Johst; Andreas K Bitz; Samaneh Shooshtary; Ashraf Abuelhaija; Maximilian N Voelker; Stefan H G Rietsch; Oliver Kraff; Stefan Maderwald; Martina Flöser; Mark Oehmigen; Harald H Quick; Mark E Ladd

doi:10.1371/journal.pone.0222452

A 32-channel parallel transmit system add-on for 7T MRI

PLoS One. 2019 Sep 12;14(9):e0222452. doi: 10.1371/journal.pone.0222452. eCollection 2019.

Authors

Stephan Orzada¹, Klaus Solbach², Marcel Gratz^{1

3}, Sascha Brunheim^{1

3}, Thomas M Fiedler⁴, Sören Johst¹, Andreas K Bitz^{4

5}, Samaneh Shooshtary², Ashraf Abuelhaija², Maximilian N Voelker^{1

3}, Stefan H G Rietsch^{1

3}, Oliver Kraff¹, Stefan Maderwald¹, Martina Flöser⁴, Mark Oehmigen³, Harald H Quick^{1

3}, Mark E Ladd^{1

4

6}

Affiliations

¹ Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
² RF & Microwave Technology, University of Duisburg-Essen, Duisburg, Germany.
³ High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany.
⁴ Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
⁵ Electromagnetic Theory and Applied Mathematics, Faculty of Electrical Engineering and Information Technology, FH Aachen - University of Applied Sciences, Aachen, Germany.
⁶ Faculty of Physics and Astronomy and Faculty of Medicine, University of Heidelberg, Heidelberg, Germany.

Abstract

Purpose: A 32-channel parallel transmit (pTx) add-on for 7 Tesla whole-body imaging is presented. First results are shown for phantom and in-vivo imaging.

Methods: The add-on system consists of a large number of hardware components, including modulators, amplifiers, SAR supervision, peripheral devices, a control computer, and an integrated 32-channel transmit/receive body array. B1+ maps in a phantom as well as B1+ maps and structural images in large volunteers are acquired to demonstrate the functionality of the system. EM simulations are used to ensure safe operation.

Results: Good agreement between simulation and experiment is shown. Phantom and in-vivo acquisitions show a field of view of up to 50 cm in z-direction. Selective excitation with 100 kHz sampling rate is possible. The add-on system does not affect the quality of the original single-channel system.

Conclusion: The presented 32-channel parallel transmit system shows promising performance for ultra-high field whole-body imaging.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Equipment Design
Humans
Magnetic Resonance Imaging / instrumentation*
Magnetic Resonance Imaging / methods*
Phantoms, Imaging
Signal-To-Noise Ratio

Grants and funding

The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 291903 MRexcite. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.