Evaluation of magnetic resonance safety of veterinary radiofrequency identification devices at 1 T.
Research
RF Safe Research Library
Jan 1, 2011
This study evaluated MRI safety parameters for three commercial veterinary RFID microchips at 1 T, assessing movement forces, heating, artifacts, and device function. Translation and torque were reported to be larger than expected from normal activity, but no significant heating was observed and microchip function…
Localizing Broca's area for transcranial magnetic stimulation: Comparison of surface distance measurements and stereotaxic positioning.
Research
RF Safe Research Library
Jan 1, 2009
This methods study evaluated an MRI-based surface distance measurements (SDM) approach for localizing Broca's area for TMS coil placement without external tracking devices. Coil positioning using SDM was compared with an advanced frameless stereotaxic navigation system. The reported mean difference between methods…
[Conclusion: probable and possible futures. MRI with ultra high magnetic field].
Research
RF Safe Research Library
Jan 1, 2009
This narrative piece states that MR neuroimaging does not interfere with brain function and is safe for use in patients and healthy volunteers. It argues that ultra-high-field MRI could substantially improve spatiotemporal resolution, potentially enabling study of brain function at finer scales. It also describes the…
In vivo quantification of contrast agent concentration using the induced magnetic field for time-resolved arterial input function measurement with MRI.
Research
RF Safe Research Library
Jan 1, 2008
This Medical Physics article presents a phase-based MRI method to quantify paramagnetic contrast agent concentration by inverting susceptibility-induced magnetic field shifts, aiming to improve arterial input function (AIF) measurement in DCE-MRI. After in vitro validation, the approach was applied in vivo in 14…
Minimal-SAR RF pulse optimization for parallel transmission in MRI.
Research
RF Safe Research Library
Jan 1, 2008
This engineering study presents an optimization framework to design RF pulses for parallel transmission MRI with the goal of minimizing SAR. Using computer simulations of a 4-channel system, the authors report significant SAR reduction while maintaining excitation pattern quality and without increasing pulse…
A benzene-core trinuclear GdIII complex: towards the optimization of relaxivity for MRI contrast agent applications at high magnetic field.
Research
RF Safe Research Library
Jan 1, 2008
This chemistry/engineering study reports the synthesis and NMR/MRI-relevant characterization of a trinuclear Gd(III) chelate intended for high-field MRI contrast applications. Using 17O NMR and proton relaxivity across multiple fields and temperatures, the authors infer bishydration, quantify water exchange and…
Magnetic field distribution and signal decay in functional mri in very high fields (up to 9.4 T) using monte carlo diffusion modeling.
Research
RF Safe Research Library
Jan 1, 2007
This paper models extravascular MRI signal decay (R2/R2*) as a function of blood oxygenation, vessel geometry, and magnetic field strength up to 9.4 T using Monte Carlo diffusion simulations. It reports different vessel-size dependencies for Hahn-spin-echo versus gradient-recalled-echo relaxation across field…
Development of a patch antenna array RF coil for ultra-high field MRI.
Research
RF Safe Research Library
Jan 1, 2007
This engineering study describes development of a patch antenna array coil (PAAC) intended to address short RF wavelength challenges in ultra-high-field (≥7T) MRI. A prototype PAAC for 7T proton imaging was used to image a monkey brain. The authors report that the imaging demonstrated the coil's utility for…