Quantitative assessment of the effects of high‐permittivity pads in 7 Tesla MRI of the brain

Abstract

The use of high-permittivity materials has been shown to be an effective method for increasing transmit and receive sensitivity in areas of low-signal intensity in the brain at high field. Results in this article show that the use of these materials does not increase the intercoil coupling for a phased array receive coil, does not have any detrimental effects on the B₀ homogeneity within the brain, and does not affect the specific absorption rate distribution within the head. Areas of the brain close to the pads exhibit significant increases (>100%) in transmit field efficiency, but areas further away show a less pronounced (∼10%) decrease due to the homogenization of the transmit field and the loss introduced by the dielectric pads. Magn Reson Med, 2012.