High-Resolution Quantitative Sodium Imaging at 9.4 Tesla

Purpose:
Investigation of the feasibility to perform highresolution 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 mm3 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 mL could be achieved at 9.4T, while maintaining an acceptable signal-tonoise ratio (8 for brain tissue and 35 for cerebrospinal fluid). The measured mean sodium concentrations for gray and white matter were 3662 and 3161 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:
Christian C. Mirkes, Jens Hoffmann, G. Shajan, Rolf Pohmann,
and Klaus Scheffler

Journal:
Magn Reson Med. (2015) Apr 4

PubMed Link:

http://www.ncbi.nlm.nih.gov/pubmed/?term=mirkes+high-resolution+9.4+Tesla