Title: On Optimization of Radiative Dipole Body Array Coils for 7 Tesla MRI,
Abstract: In this contribution we present numerical and experimental results of a
parametric study of radiative dipole antennas in a phased array configuration
for efficient body magnetic resonance imaging at 7T via parallel transmit. For
magnetic resonance imaging (MRI) at ultrahigh fields (7T and higher) dipole
antennas are commonly used in phased arrays, particularly for body imaging
targets. This study reveals the effects of dipole positioning in the array
(elevation of dipoles above the subject and inter-dipole spacing) on their
mutual coupling, $B_1^{+}$ per unit power and $B_1^{+}$ per maximum local SAR
efficiencies as well as the RF-shimming capability. The results demonstrate the
trade-off between low maximum local SAR and sensitivity to the subject
variation and provide the working parameter range for practical body arrays
composed of recently suggested fractionated dipoles.