An Assessment of the Suitability of the Body and Adult Head Coils for Transmission during Paediatric Magnetic Resonance Imaging

G.R. Cook[1], M.J. Graves[1], F.J. Robb[2], D.J. Lomas[1]
[1]Department of Radiology, University of Cambridge, Cambridge, United Kingdom
[2]General Electric Healthcare Coils, Aurora, Ohio, USA
Published in 2013

MRI offers many advantages over other modalities and its lack of ionizing radiation is important for children, but can be limited by the radio-frequency (RF) coils available. This work calculates Specific Absorption Rate (SAR) and homogeneity of the RF transmit field (B1+) when imaging infants in adult coils.

Two birdcage-type coils were loaded by a tissue model and their B1+ homogeneities calculated. SAR values were normalized to the whole-body guideline and examined for ‘hot spots’ exceeding the 1g limit. Bio-Heat simulations were used to calculate temperature change.

The body coil produced a more homogeneous B1+, however, maximum SAR was lower for the head coil (63.35 W/kg compared to 67.37W/kg); temperatures rose in high SAR areas skin cooling was significant.

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