title: Sodium MRI of the human heart at 7.0 T: preliminary results.
abstract: The objective of this work was to examine the feasibility of three-dimensional (3D) and whole heart coverage (23)Na cardiac MRI at 7.0 T including single-cardiac-phase and cinematic (cine) regimes. A four-channel transceiver RF coil array tailored for (23)Na MRI of the heart at 7.0 T (f = 78.5 MHz) is proposed. An integrated bow-tie antenna building block is used for (1)H MR to support shimming, localization and planning in a clinical workflow. Signal absorption rate simulations and assessment of RF power deposition were performed to meet the RF safety requirements. (23) Na cardiac MR was conducted in an in vivo feasibility study. 3D gradient echo (GRE) imaging in conjunction with Cartesian phase encoding (total acquisition time T(AQ)  = 6 min 16 s) and whole heart coverage imaging employing a density-adapted 3D radial acquisition technique (T(AQ)  = 18 min 20 s) were used. For 3D GRE-based (23)Na MRI, acquisition of standard views of the heart using a nominal in-plane resolution of (5.0 × 5.0) mm(2) and a slice thickness of 15 mm were feasible. For whole heart coverage 3D density-adapted radial (23)Na acquisitions a nominal isotropic spatial resolution of 6 mm was accomplished. This improvement versus 3D conventional GRE acquisitions reduced partial volume effects along the slice direction and enabled retrospective image reconstruction of standard or arbitrary views of the heart. Sodium cine imaging capabilities were achieved with the proposed RF coil configuration in conjunction with 3D radial acquisitions and cardiac gating. Cardiac-gated reconstruction provided an enhancement in blood-myocardium contrast of 20% versus the same data reconstructed without cardiac gating. The proposed transceiver array enables (23)Na MR of the human heart at 7.0 T within clinical acceptable scan times. This capability is in positive alignment with the needs of explorations that are designed to examine the potential of (23)Na MRI for the assessment of cardiovascular and metabolic diseases.
authors.affiliation: Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Graessl
authors.affiliation: Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
authors.forename: Anjuli
authors.initials: A
authors.lastname: Ruehle
authors.affiliation: MRI.TOOLS, Berlin, Germany.
authors.forename: Helmar
authors.initials: H
authors.lastname: Waiczies
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Ana
authors.initials: A
authors.lastname: Resetar
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Stefan H
authors.initials: SH
authors.lastname: Hoffmann
authors.affiliation: MRI.TOOLS, Berlin, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Rieger
authors.affiliation: Trinity College, Institute of Neuroscience, The University of Dublin, Ireland.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Wetterling
authors.affiliation: Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
authors.forename: Lukas
authors.initials: L
authors.lastname: Winter
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Armin M
authors.initials: AM
authors.lastname: Nagel
authors.affiliation: Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.|Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany.
authors.forename: Thoralf
authors.initials: T
authors.lastname: Niendorf
mesh_terms: D000328:Adult; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods*; D009206:Myocardium / Q000378:metabolism*; D010865:Pilot Projects; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012964:Sodium / Q000378:metabolism*; D012975:Sodium Isotopes / Q000493:pharmacokinetics
chemical_list: D019275:Radiopharmaceuticals; D012975:Sodium Isotopes; D012964:Sodium
keywords: MRI; RF coil technology; cardiovascular MRI; sodium imaging; transceiver array; ultrahigh field MR