The Application of Surface Coils for Tissue Characterization — Demonstrated by the Determination of T2 Relaxation Times

Abstract

T2 values are usually calculated from magnetic resonance (MR) measurements with homogeneous RF transmitting and receiving fields using body or head resonators for the examination of humans. However, these resonators have a reduced signal-to-noise ratio (S/N) compared to that of surface coil receiving (Zabel et al. 1987). The high contrast and spatial resolution achieved with surface coils improve the quantitative tissue characterization or the quantification of spin motion (Mueller et al. 1986). On the other hand, the high signal yield of a surface coil decreases with the distance to the coil, the slope of the decay depending on the coil radius. Up to a distance of nearly the coil diameter the S/N is higher than that of a body or head resonator; therefore a better determination of relaxation times in superficial tissues is possible.