Mladen Barbic1, Stephen J Dodd2, Hatem ElBidweihy3, Neil R Dilley4, Barbara Marcheschi5, Alan L Huston5, H Douglas Morris6, Alan P Koretsky2. 1. Howard Hughes Medical Institute-Janelia Research Campus, Ashburn, Virginia, USA. 2. Laboratory of Functional and Molecular Imaging, NIH/NINDS, Bethesda, Maryland, USA. 3. Electrical and Computer Engineering Department, United States Naval Academy, Annapolis, Maryland, USA. 4. Quantum Design, San Diego, California, USA. 5. Optical Sciences Division, US Naval Research Laboratory, Washington, DC, USA. 6. NIH Mouse Imaging Facility, NIH/NINDS, Bethesda, Maryland, USA.
Abstract
PURPOSE: Demonstrating multifield and inverse contrast switching of magnetocaloric high contrast ratio MRI labels that either have increasing or decreasing moment versus temperature slopes depending on the material at physiological temperatures and different MRI magnetic field strengths. METHODS: Two iron-rhodium samples of different purity (99% and 99.9%) and a lanthanum-iron-silicon sample were obtained from commercial vendors. Temperature and magnetic field-dependent magnetic moment measurements of the samples were performed on a vibrating sample magnetometer. Temperature-dependent MRI of different iron-rhodium and lanthanum-iron-silicon samples were performed on 3 different MRI scanners at 1 Tesla (T), 4.7T, and 7T. RESULTS: Sharp, first-order magnetic phase transition of each iron-rhodium sample at a physiologically relevant temperature (~37°C) but at different MRI magnetic fields (1T, 4.7T, and 7T, depending on the sample) showed clear image contrast changes in temperature-dependent MRI. Iron-rhodium and lanthanum-iron-silicon samples with sharp, first-order magnetic phase transitions at the same MRI field of 1T and physiological temperature of 37°C, but with positive and negative slope of magnetization versus temperature, respectively, showed clear inverse contrast image changes. Temperature-dependent MRI on individual microparticle samples of lanthanum-iron-silicon also showed sharp image contrast changes. CONCLUSION: Magnetocaloric materials of different purity and composition were demonstrated to act as diverse high contrast ratio switchable MRI contrast agents. Thus, we show that a range of magnetocaloric materials can be optimized for unique image contrast response under MRI-appropriate conditions at physiological temperatures and be controllably switched in situ.
PURPOSE: Demonstrating multifield and inverse contrast switching of magnetocaloric high contrast ratio MRI labels that either have increasing or decreasing moment versus temperature slopes depending on the material at physiological temperatures and different MRI magnetic field strengths. METHODS: Two iron-rhodium samples of different purity (99% and 99.9%) and a lanthanum-iron-silicon sample were obtained from commercial vendors. Temperature and magnetic field-dependent magnetic moment measurements of the samples were performed on a vibrating sample magnetometer. Temperature-dependent MRI of different iron-rhodium and lanthanum-iron-silicon samples were performed on 3 different MRI scanners at 1 Tesla (T), 4.7T, and 7T. RESULTS: Sharp, first-order magnetic phase transition of each iron-rhodium sample at a physiologically relevant temperature (~37°C) but at different MRI magnetic fields (1T, 4.7T, and 7T, depending on the sample) showed clear image contrast changes in temperature-dependent MRI. Iron-rhodium and lanthanum-iron-silicon samples with sharp, first-order magnetic phase transitions at the same MRI field of 1T and physiological temperature of 37°C, but with positive and negative slope of magnetization versus temperature, respectively, showed clear inverse contrast image changes. Temperature-dependent MRI on individual microparticle samples of lanthanum-iron-silicon also showed sharp image contrast changes. CONCLUSION: Magnetocaloric materials of different purity and composition were demonstrated to act as diverse high contrast ratio switchable MRI contrast agents. Thus, we show that a range of magnetocaloric materials can be optimized for unique image contrast response under MRI-appropriate conditions at physiological temperatures and be controllably switched in situ.
Authors: Nathaniel I Matter; Greig C Scott; Thomas Grafendorfer; Albert Macovski; Steven M Conolly Journal: IEEE Trans Med Imaging Date: 2006-01 Impact factor: 10.048
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Authors: Li Liu; Steve Dodd; Ryan D Hunt; Nikorn Pothayee; Tatjana Atanasijevic; Nadia Bouraoud; Dragan Maric; E Ashley Moseman; Selamawit Gossa; Dorian B McGavern; Alan P Koretsky Journal: Elife Date: 2022-05-05 Impact factor: 8.713