Laura Boehmert1, Andre Kuehne2, Helmar Waiczies2, Daniel Wenz1, Thomas Wilhelm Eigentler1, Stephanie Funk3, Florian von Knobelsdorff-Brenkenhoff3,4, Jeanette Schulz-Menger3,5, Armin M Nagel6,7,8, Erdmann Seeliger9, Thoralf Niendorf1,2,5,10. 1. Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany. 2. MRI.TOOLS GmbH, Berlin, Germany. 3. Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Helios Clinics Berlin-Buch, Berlin, Germany. 4. Clinic Agatharied, Dept. of Cardiology, Academic Teaching Hospital of the Ludwig-Maximilians-University Munich, Hausham, Germany. 5. DZHK (German Centre for Cardiovascular Research), partner site Berlin, Germany. 6. Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany. 7. Division of Medical Physics in Radiology, German Cancer Research Centre (DKFZ), Heidelberg, Germany. 8. Institute of Medical Physics, University of Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany. 9. Institute of Vegetative Physiology, Charité University Medicine, Berlin, Germany. 10. Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Abstract
PURPOSE: Cardiorenal syndrome describes disorders of the heart and the kidneys in which a dysfunction of 1 organ induces a dysfunction in the other. This work describes the design, evaluation, and application of a 4/4-channel hydrogen-1/sodium (1 H/23 Na) RF array tailored for cardiorenal MRI at 7.0 Tesla (T) for a better physiometabolic understanding of cardiorenal syndrome. METHODS: The dual-frequency RF array is composed of a planar posterior section and a modestly curved anterior section, each section consisting of 2 loop elements tailored for 23 Na MR and 2 loopole-type elements customized for 1 H MR. Numerical electromagnetic field and specific absorption rate simulations were carried out. Transmission field ( B 1 + ) uniformity was optimized and benchmarked against electromagnetic field simulations. An in vivo feasibility study was performed. RESULTS: The proposed array exhibits sufficient RF characteristics, B 1 + homogeneity, and penetration depth to perform 23 Na MRI of the heart and kidney at 7.0 T. The mean B 1 + field for sodium in the heart is 7.7 ± 0.8 µT/√kW and in the kidney is 6.9 ± 2.3 µT/√kW. The suitability of the RF array for 23 Na MRI was demonstrated in healthy subjects (acquisition time for 23 Na MRI: 18 min; nominal isotropic spatial resolution: 5 mm [kidney] and 6 mm [heart]). CONCLUSION: This work provides encouragement for further explorations into densely packed multichannel transceiver arrays tailored for 23 Na MRI of the heart and kidney. Equipped with this technology, the ability to probe sodium concentration in the heart and kidney in vivo using 23 Na MRI stands to make a critical contribution to deciphering the complex interactions between both organs.
PURPOSE:Cardiorenal syndrome describes disorders of the heart and the kidneys in which a dysfunction of 1 organ induces a dysfunction in the other. This work describes the design, evaluation, and application of a 4/4-channel hydrogen-1/sodium (1 H/23 Na) RF array tailored for cardiorenal MRI at 7.0 Tesla (T) for a better physiometabolic understanding of cardiorenal syndrome. METHODS: The dual-frequency RF array is composed of a planar posterior section and a modestly curved anterior section, each section consisting of 2 loop elements tailored for 23 Na MR and 2 loopole-type elements customized for 1 H MR. Numerical electromagnetic field and specific absorption rate simulations were carried out. Transmission field ( B 1 + ) uniformity was optimized and benchmarked against electromagnetic field simulations. An in vivo feasibility study was performed. RESULTS: The proposed array exhibits sufficient RF characteristics, B 1 + homogeneity, and penetration depth to perform 23 Na MRI of the heart and kidney at 7.0 T. The mean B 1 + field for sodium in the heart is 7.7 ± 0.8 µT/√kW and in the kidney is 6.9 ± 2.3 µT/√kW. The suitability of the RF array for 23 Na MRI was demonstrated in healthy subjects (acquisition time for 23 Na MRI: 18 min; nominal isotropic spatial resolution: 5 mm [kidney] and 6 mm [heart]). CONCLUSION: This work provides encouragement for further explorations into densely packed multichannel transceiver arrays tailored for 23 Na MRI of the heart and kidney. Equipped with this technology, the ability to probe sodium concentration in the heart and kidney in vivo using 23 Na MRI stands to make a critical contribution to deciphering the complex interactions between both organs.
Authors: William D Watson; Jack J J Miller; Andrew Lewis; Stefan Neubauer; Damian Tyler; Oliver J Rider; Ladislav Valkovič Journal: Cardiovasc Diagn Ther Date: 2020-06