Investigating the level of signal-to-noise ratio performance of a quadrature head coil in MRI

The following study sought to investigate the level of SNR performance obtainable from a particular MR system (1.5 T GE Signa Horizon™) using the system's quadrature head coil only. The method used for identifying the level of SNR performance of the particular system's quadrature head coil was the same method employed by MagNET (the subdivision of Medical Devices Agency which is responsible for MR technology) in order to produce the official evaluation reports for all MR systems currently available. The SNR test method is based on the National Electrical Manufacturers Association (NEMA) standard for SNR measurements. Therefore, a comparison of the results from this study with the results available in the MDA evaluation report for this particular MR system would ultimately reveal the true SNR performance at the time of testing. SNR measurements in all three imaging planes were obtained and despite the insignificant deviation in the axial plane which was 2.9%, the SNR performance in the sagittal and coronal planes was found to be below the expected, and were 15.2% and 11.6% respectively. This deviation can be related to a number of factors which will be presented.