Analysis of Blurring Due to Short T2 Decay at Different Resolutions in 23na MRI

The nuclear magnetic resonance signal from sodium (23Na) nuclei demonstratesa fast bi-exponential T2 decay in biological tissues (T2,short = 0.5-5 ms andT2,long = 10-30 ms). Hence, blurring observed in sodium images acquired withcenter-out sequences is generally assumed to be dominated by signal attenuationat higher k-space frequencies. Most of the studies in the field primarily focuson the impact of readout duration on blurring but neglect the impact ofresolution. In this paper, we examine the blurring effect of short T2 on imagesat different resolutions. A series of simulations, as well as phantom and invivo scans were performed at varying resolutions and readout durations in orderto evaluate progressive changes in image quality. We demonstrate that, given afixed readout duration, T2 decay produces distinct blurring effects atdifferent resolutions. Therefore, in addition to voxel size-dependent partialvolume effects, the choice of resolution adds additional T2-dependent blurring.