4709212 Method of enhancing image signal-to-noise ratio by combining NMR images of differing pulse sequence timing

Abstract

A method is provided for enhancing image signal-to-noise ratio (SNR) by combining NMR acquired images of differing pulse sequence timing. In one embodiment, a plurality of multi-echo images acquired at different spin-echo times are used to compute values of spin-spin relaxation (T 2 ) and pseudospin density (PD) for each pixel in the multi-echo images. These values are used to generate new images at a spin-echo time TE c for which actual measurements may not have been taken. In another embodiment, the calculated T 2 images are used to extrapolate (by multiplying each pixel by an appropriate factor) each of the acquired images to some spin-echo time TE c . The extrapolated image can now be averaged to produce an image with improved SNR. In yet another embodiment, similar techniques are used to improve the SNR of images acquired by varying parameters, such as pulse sequence repetition time TR, which effect the spin-lattice (T 1 ) dependence of the image.