AN ORTHOGONAL CORRELATION ALGORITHM FOR GHOST REDUCTION IN MRI

Ghosting in MRI due to modulation of k-space data can be caused by mot ion of the subject or characteristics of the sequence. A general solut ion for 2DFT MRI that reduces ghosting without causal modeling is pres ented, Separate image data sets are acquired in which the phase and fr equency directions are swapped, In these two data sets, the image sign al is correlated, whereas the ghost signals are not, By taking a corre lation of these two data sets, an image with greatly reduced ghosting is obtained. The reduction is shown to depend both on the correct sign al intensity of the image, as well as the ghost intensity in the ghost ed region. The reduction approaches 100% in regions of low image signa l, and is more moderate in regions of higher image signal. The process was applied to conventional spin-echo, fast-spin-echo, and gradient e cho imaging of volunteers and a phantom. Results of a reader study of the volunteer images reflected a significant overall reduction of ghos ting artifacts in all volunteer experiments.