Diffusion-weighted interleaved echo-planar imaging with a pair of orthogonal navigator echoes.
This work describes a diffusion-weighted (DW) interleaved echo-planar imaging (IEPI) method for use on either conventional whole-body scanners or scanners equipped with high-speed gradient and receiver hardware. In combination with cardiac gating and motion correction with a pair of orthogonal navigator echoes, the presented method is time-efficient, compensates for patient motions, and is less sensitive to image distortions than single-shot methods. The motion-correction scheme consists of correction for constant and linear phase terms found from the orthogonal navigator echoes. The correction for the linear phase term in the phase-encode direction includes gridding the data to the Cartesian grid. The DW IEPI was used to image a phantom rotating about the slice-select direction, and motion correction was performed to eliminate ghost artifacts arising from motion in either the readout- or phase-encoding directions. DW IEPI with motion correction was performed on a normal volunteer and on a patient with a 26-day-old region of ischemia over much of the right hemisphere.
Butts
K
K
Department of Radiology, Stanford University, CA 94305-5488, USA.
de Crespigny
A
A
Pauly
J M
JM
Moseley
M
M
D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology / Q000473:pathology*; D002545:Brain Ischemia / Q000175:diagnosis*; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009038:Motion; D019047:Phantoms, Imaging