Md. Robson et al., DIFFUSION-WEIGHTED MULTIPLE SHOT ECHO-PLANAR IMAGING OF HUMANS WITHOUT NAVIGATION, Magnetic resonance in medicine, 38(1), 1997, pp. 82-88
A new method is proposed for reducing the artifacts produced in diffus
ion-weighted imaging, When data are acquired using multiple shot echo
planar acquisitions, conventional reconstruction methods produce artif
actual images as a consequence of diffusion weighting and small amount
s of bulk motion of the subject, If the amount of motion can be determ
ined, it is possible to correct the data before reconstruction, which
removes the artifact. A method for estimating the motion from the acqu
ired data has been developed and evaluated, This method assumes that g
host image effects will be minimized when motion has been correctly co
mpensated, By considering the amount of signal in the background of th
e image, appropriate corrections to the data can be made, and the accu
racy of the motion compensation may be estimated, This technique has b
een evaluated by computer simulation, and its performance has been dem
onstrated in a phantom and humans with both two- and four-shot echo pl
anar acquisitions and using both ''mosaic'' and ''interleaved'' sampli
ng schemes.