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Interleaved 23 Na / 1 H MRI of the human heart at 7 T using a combined 23 Na / 1 H coil setup and 1 H parallel transmission
Author(s) -
Ruck Laurent,
Egger Nico,
Wilferth Tobias,
Schirmer Judith,
Gast Lena Vanessa,
Nagelstraßer Sophia,
Wildenberg Saskia,
Bitz Andreas,
Lanz Titus,
Platt Tanja,
Konstandin Simon,
Kopp Christoph,
Uder Michael,
Nagel Armin Michael
Publication year - 2025
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.30426
Subject(s) - shim (computing) , nuclear magnetic resonance , analytical chemistry (journal) , nuclear medicine , chemistry , physics , medicine , chromatography , erectile dysfunction
Abstract Purpose To evaluate the feasibility of interleaved 23 Na/ 1 H cardiac MRI at 7 T using 1 H parallel transmission (pTx) pulses. Methods A combined setup consisting of a 23 Na volume coil and two 1 H transceiver arrays was employed and the transmit and receive characteristics were compared in vitro with those of the uncombined radiofrequency coils. Furthermore, the implemented interleaved 23 Na/ 1 H pTx sequence was validated in phantom measurements and applied to four healthy subjects. For the latter, three customized 1 H excitation pulses (universal and individual phase shims (UPS/IPS) and individual 4kT pulses (4kT)) were employed in the interleaved 23 Na/ 1 H pTx sequence and compared with the vendor‐provided default cardiac phase shim (DPS). Results Combining both coils resulted in a reduction of the mean 23 Na transmit field (B 1 + ) efficiency and 23 Na signal‐to‐noise ratio by 18.9% and 15.4% for the combined setup, whereas the 1 H B 1 + efficiency was less influenced (−4.7%). Compared with single‐nuclear acquisitions, interleaved dual‐nuclear 23 Na/ 1 H MRI showed negligible influence on 23 Na and 1 H image quality. For all three customized 1 H pTx pulses the B 1 + homogeneity was improved (coefficients of variation: CV UPS = 0.30, CV IPS = 0.23, CV 4kT = 0.15) and no 1 H signal dropouts occurred compared with the vendor‐provided default phase shim (CV DPS = 0.37). Conclusion The incorporation of customized 1 H pTx pulses in an interleaved 23 Na/ 1 H sequence scheme was successfully demonstrated at 7 T and improvements of the 1 H B 1 + homogeneity within the heart were shown. Combining interleaved 23 Na/ 1 H MRI with 1 H pTx is an important tool to enable robust quantification of myocardial tissue sodium concentrations at 7 T within clinically acceptable acquisition times.