SIGNAL-TO-NOISE MEASURES FOR MAGNETIC-RESONANCE IMAGERS

The signal-to-noise ratio (SNR) in magnetic resonance imaging represen ts one of the system operating variables that must be determined both for evaluating the performance of different imaging protocols on a par ticular machine, and for monitoring machine performance as part of a r outine quality control (QC) program. Utilizing a phantom and set of au tomated analysis programs currently under development, this study eval uated several ways of measuring image signal and noise and demonstrate d the importance of utilizing measured voxel volumes as opposed to nom inal volumes in the calculation of SNR. The NEMA proposed standard for SNR is compared with several other SNR measures and is recommended as the measure to be used in routine SNR reporting. The importance of ut ilizing other SNR measures in addition to the NEMA proposed standard f or routine QC is discussed.