SIGNAL-TO-NOISE MEASUREMENTS IN MAGNITUDE IMAGES FROM NMR PHASED-ARRAYS

A method is proposed to estimate signal-to-noise ratio (SNR) values in phased array magnitude images, based on a region-of-interest (ROI) an alysis. it is shown that the SNR can be found by correcting the measur ed signal intensity for the noise bias effects and by evaluating the n oise variance as the mean square value of all the pixel intensities in a chosen background ROI, divided by twice the number of receivers use d. Estimated SNR values are shown to vary spatially within a bound of 20% with respect to the true SNR values as a result of noise correlati ons between receivers.