An optimized pulse sequence for isotropically weighted diffusion imaging.
Single-shot echo-planar imaging is becoming the most widely used technique for magnetic resonance diffusion imaging, since it enables measurement of diffusion coefficients in human brain without motion artifacts. However, its reliability is limited by geometrical distortions due to eddy currents. In this report, an isotropically weighted echo-planar pulse sequence, optimized to give the maximum signal-to-noise ratio in the computed trace image and designed to produce inherently low distortions, is presented. It is also shown how the residual translational distortion can be easily characterized and removed by postprocessing. A full characterization of the distortion artifact involves a few measurements on a phantom, in order to estimate the distortion as a function of slice orientation, which can then be used to correct any slice orientation. Results of applying the image translation correction to data collected from a patient are presented.
Cercignani
M
M
Division of Medical Physics, University of Leicester, Leicester, LE1 5WW, United Kingdom.
Horsfield
M A
MA
D016477:Artifacts; D001921:Brain / Q000473:pathology*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008433:Mathematics; D019047:Phantoms, Imaging; D020521:Stroke / Q000473:pathology*