Christian C Mirkes1,2, Jens Hoffmann2, G Shajan2, Rolf Pohmann2, Klaus Scheffler1,2. 1. Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany. 2. High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
Abstract
PURPOSE: Investigation of the feasibility to perform high-resolution quantitative sodium imaging at 9.4 Tesla (T). METHODS: A proton patch antenna was combined with a sodium birdcage coil to provide a proton signal without compromising the efficiency of the X-nucleus coil. Sodium density weighted images with a nominal resolution of 1 × 1 × 5 mm(3) were acquired within 30 min with an ultrashort echo time sequence. The methods used for signal calibration as well as for B0, B1, and off-resonance correction were verified on a phantom and five healthy volunteers. RESULTS: An actual voxel volume of roughly 40 μL could be achieved at 9.4T, while maintaining an acceptable signal-to-noise ratio (8 for brain tissue and 35 for cerebrospinal fluid). The measured mean sodium concentrations for gray and white matter were 36 ± 2 and 31 ± 1 mmol/L of wet tissue, which are comparable to values previously reported in the literature. CONCLUSION: The reduction of partial volume effects is essential for accurate measurement of the sodium concentration in the human brain. Ultrahigh field imaging is a viable tool to achieve this goal due to its increased sensitivity.
PURPOSE: Investigation of the feasibility to perform high-resolution quantitative sodium imaging at 9.4 Tesla (T). METHODS: A proton patch antenna was combined with a sodium birdcage coil to provide a proton signal without compromising the efficiency of the X-nucleus coil. Sodium density weighted images with a nominal resolution of 1 × 1 × 5 mm(3) were acquired within 30 min with an ultrashort echo time sequence. The methods used for signal calibration as well as for B0, B1, and off-resonance correction were verified on a phantom and five healthy volunteers. RESULTS: An actual voxel volume of roughly 40 μL could be achieved at 9.4T, while maintaining an acceptable signal-to-noise ratio (8 for brain tissue and 35 for cerebrospinal fluid). The measured mean sodium concentrations for gray and white matter were 36 ± 2 and 31 ± 1 mmol/L of wet tissue, which are comparable to values previously reported in the literature. CONCLUSION: The reduction of partial volume effects is essential for accurate measurement of the sodium concentration in the human brain. Ultrahigh field imaging is a viable tool to achieve this goal due to its increased sensitivity.
Authors: Keith Thulborn; Elaine Lui; Jonathan Guntin; Saad Jamil; Ziqi Sun; Theodore C Claiborne; Ian C Atkinson Journal: NMR Biomed Date: 2015-06-09 Impact factor: 4.044
Authors: Keith R Thulborn; Chao Ma; Chenhao Sun; Ian C Atkinson; Theodore Claiborne; Reiner Umathum; Steven M Wright; Zhi-Pei Liang Journal: J Magn Reson Date: 2018-06-29 Impact factor: 2.229