Journal Article

DKFZ-2022-01005

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Double-Row Dipole/Loop Combined Array for Human Whole Brain Imaging at 7 T.

Avdievich, N. I. ; Nikulin, A. V. ; Ruhm, L. ; Magill, A.DKFZ* ; Henning, A. ; Scheffler, K.

2022
Wiley New York, NY

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Please use a persistent id in citations: doi:10.1002/nbm.4773

Abstract: Important issues in designing radiofrequency (RF) coils for human head imaging at ultra-high field (UHF, > 7T) are the inhomogeneity and longitudinal coverage (along the magnet axis) of the transmit (Tx) RF field. Both the homogeneity and coverage produced by Tx volume coils can be improved by means of 3D RF shimming, which requires use of multi-row Tx-arrays. In addition, according to recent findings of the ultimate intrinsic SNR theory, the loop-only receive (Rx) arrays don't provide optimal SNR near the brain center at UHF. The latter can be obtained by combining complementary conductive structures carrying different current patterns, e.g. loops and dipole antennas. In this work, we developed, constructed, and evaluated a novel 32-element hybrid array design for human head imaging at 7 T. The array consists of 16 transceiver loops placed in two rows circumscribing the head and 16 folded-end Rx-only dipoles positioned in the centers of loops. By placing all elements in a single layer, we increased RF power deposition into the tissue and, thus, preserved the Tx-efficiency. Using this hybrid design also simplifies the coil structure by minimizing the total number of array elements. The array demonstrated whole brain coverage, 3D shimming capability and high SNR. It provided ~15% higher SNR near the brain center and depending on the RF shim mode from 20% to 40% higher Tx-efficiency than a common commercial head array coil.

Keyword(s): Ultra-high field MRI ; central SNR improvement ; folded-end dipole ; human head imaging ; hybrid array design ; whole brain coverage

Note: 2022 Oct;35(10):e4773

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Contributing Institute(s):

1. E020 Med. Physik in der Radiologie (E020)

Research Program(s):

1. 315 - Bildgebung und Radioonkologie (POF4-315) (POF4-315)

Appears in the scientific report 2022

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; DEAL Wiley ; Essential Science Indicators ; IF < 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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