Meeting Banner
Abstract #0287

Parallel Transmit Excitation at 1.5 T Based on the Minimization of a Driving Function for Device Heating

Natalia Gudino1, 2, Merdim Sonmez2, Anthony Z. Faranesh2, Robert J. Lederman2, Robert S. Balaban2, Michael Schacht Hansen2, Mark A. Griswold1, 3

1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States; 2Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States; 3Department of Radiology, Case Western Reserve University, Cleveland, OH, United States

A transmit planar coil array driven by near-coil current-source amplifier was implemented in iMRI setup to reduce the RF E-field coupling and consequent heating in a wire/guidewire. An optimum set of phases was obtained through minimization of a driving function (W) for device heating and tested in a MRI phantom and animal experiments. Up to 92 % temperature reduction was measured at the tip of the device when transmitting with the array in an optimum phase configuration instead of using the conventional body coil transmitter. B1 constrained minimization of W at predefined ROIs was proposed and tested on the benchtop.

Keywords

achieved active allow amplifiers amplitude anesthetized animal applying approved approximately around array arrow attached audience back bare bell biomedical blood body bottom built care channel code coil committee complex conductors configurations confirmed connections considerable constrained control coupled coupling covered cycle degrees device devices direct division driven driving duty effectively engineering equations equivalent excitation exit experiment exploiting exposed feedback femoral fiber field finally foot freedom function head health heart heating homogeneity house human immersed in vivo increment induced insert inserted institutes insulated intramural keeping loaded loading local location long loops lumen lung made mapping mark marked maxwell measured minimization minimized minute national near noise parallel park pelvis phantom planar potential predefined preliminary previously pulling pulse radiology reasonable reduce reduced reduction replacing reserve respectively safety saline sensor setup setups simulated solution source space spot steady steps straight subtracting superficially system target temperature thesis torso trajectories transmission transmit transmitter transmitting vector vectors western white wire wright