title: Directly detected (55)Mn MRI: application to phantoms for human hyperpolarized (13)C MRI development.
abstract: In this work we demonstrate for the first time directly detected manganese-55 ((55)Mn) magnetic resonance imaging (MRI) using a clinical 3T MRI scanner designed for human hyperpolarized (13)C clinical studies with no additional hardware modifications. Due to the similar frequency of the (55)Mn and (13)C resonances, the use of aqueous permanganate for large, signal-dense, and cost-effective "(13)C" MRI phantoms was investigated, addressing the clear need for new phantoms for these studies. Due to 100% natural abundance, higher intrinsic sensitivity, and favorable relaxation properties, (55)Mn MRI of aqueous permanganate demonstrates dramatically increased sensitivity over typical (13)C phantom MRI, at greatly reduced cost as compared with large (13)C-enriched phantoms. A large sensitivity advantage (22-fold) was demonstrated. A cylindrical phantom (d=8 cm) containing concentrated aqueous sodium permanganate (2.7 M) was scanned rapidly by (55)Mn MRI in a human head coil tuned for (13)C, using a balanced steady state free precession acquisition. The requisite penetration of radiofrequency magnetic fields into concentrated permanganate was investigated by experiments and high frequency electromagnetic simulations, and found to be sufficient for (55)Mn MRI with reasonably sized phantoms. A sub-second slice-selective acquisition yielded mean image signal-to-noise ratio of ~60 at 0.5 cm(3) spatial resolution, distributed with minimum central signal ~40% of the maximum edge signal. We anticipate that permanganate phantoms will be very useful for testing HP (13)C coils and methods designed for human studies.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA. Electronic address: cornelius.vonmorze@ucsf.edu.
authors.forename: Cornelius
authors.initials: C
authors.lastname: von Morze
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA.
authors.forename: Lucas
authors.initials: L
authors.lastname: Carvajal
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA.
authors.forename: Galen D
authors.initials: GD
authors.lastname: Reed
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA.
authors.forename: Christine Leon
authors.initials: CL
authors.lastname: Swisher
authors.affiliation: GE Healthcare, Fremont, CA.
authors.forename: James
authors.initials: J
authors.lastname: Tropp
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Vigneron
mesh_terms: D002244:Carbon / Q000737:chemistry; D002247:Carbon Isotopes; D060733:Electromagnetic Radiation; D006801:Humans; D016018:Least-Squares Analysis; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008345:Manganese / Q000737:chemistry; D017895:Manganese Compounds / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D017670:Sodium Compounds / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D017895:Manganese Compounds; D010087:Oxides; D017670:Sodium Compounds; C048856:permanganic acid; D008345:Manganese; D002244:Carbon; C035328:sodium permanganate
keywords: Carbon; Hyperpolarized; Manganese; Permanganate; Phantom