Toward whole-cortex enhancement with an ultrahigh dielectric constant helmet at 3T.

Autor: Sica CT; Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania., Rupprecht S; HyQ Research Solutions, LLC, State College, Pennsylvania., Hou RJ; Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania., Lanagan MT; HyQ Research Solutions, LLC, State College, Pennsylvania., Gandji NP; Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania., Lanagan MT; Department of Engineering Science and Mechanics, University Park, Pennsylvania.; Department of Neurosurgery, Pennsylvania State University College of Medicine, Hershey, Pennsylvania., Yang QX; Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.; HyQ Research Solutions, LLC, State College, Pennsylvania.; Department of Neurosurgery, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.
Jazyk: angličtina
Zdroj: Magnetic resonance in medicine [Magn Reson Med] 2020 Mar; Vol. 83 (3), pp. 1123-1134. Date of Electronic Publication: 2019 Sep 10.
DOI: 10.1002/mrm.27962
Abstrakt: Purpose: To present a 3T brain imaging study using a conformal prototype helmet constructed with an ultra-high dielectric constant (uHDC; ε r ~ 1000) materials that can be inserted into standard receive head-coils.
Methods: A helmet conformal to a standard human head constructed with uHDC materials was characterized through electromagnetic simulations and experimental work. The signal-to-noise ratio (SNR), transmit efficiency, and power deposition with the uHDC helmet inserted within a 20-channel head coil were measured in vivo and compared with a 64-channel head coil and the 20-channel coil without the helmet. Seven healthy volunteers were analyzed.
Results: Simulation and in vivo experimental results showed that transmit efficiency was improved by nearly 3 times within localized regions for a quadrature excitation, with a measured global increase of 58.21 ± 6.54% over 7 volunteers. The use of a parallel transmit spokes pulse compensated for severe degradation of B 1 + homogeneity, at the expense of higher global and local specific absorption rate levels. A SNR histogram analysis with statistical testing demonstrated that the uHDC helmet enhanced a 20-channel head coil to the level of the 64-channel head coil, with the improvements mainly within the cortical brain regions.
Conclusion: A prototype uHDC helmet enhanced the SNR of a standard head coil to the level of a high density 64-channel coil, although transmit homogeneity was compromised. Further improvements in SNR may be achievable with optimization of this technology, and could be a low-cost approach for future radiofrequency engineering work in the brain at 3T.
(© 2019 International Society for Magnetic Resonance in Medicine.)
Databáze: MEDLINE
Externí odkaz: