Rapid autocorrection using prescan navigator echoes

Autocorrection is an adaptive motion correction algorithm that does not require an in vivo measurement of the motion record. A novel method for ensuring convergence of this algorithm when motion is severe is presented. A limited number of navigator echoes are acquired before the imaging sequence to obtain a “snapshot” of the object. Phase differences between the navigator and image k‐space data are used as an estimate of motion‐induced phase shifts in the image, followed by autocorrection. In phantom data a six‐fold reduction in computation time compared to autocorrection alone was realized. These results indicate that this navigator/autocorrection combination may be useful for reducing motion artifacts and computation time for MR exams when motion along the image phase encoding axis is severe. Magn Reson Med 43:583–588, 2000. © 2000 Wiley‐Liss, Inc.

[1]  J C Gore,et al.  Analysis and correction of motion artifacts in diffusion weighted imaging , 1994, Magnetic resonance in medicine.

[2]  J. Felmlee,et al.  Adaptive technique for high-definition MR imaging of moving structures. , 1989, Radiology.

[3]  David Atkinson,et al.  Automatic correction of motion artifacts in magnetic resonance images using an entropy focus criterion , 1997, IEEE Transactions on Medical Imaging.

[4]  Ronald N. Bracewell,et al.  The Fourier Transform and Its Applications , 1966 .

[5]  A. G. Collins,et al.  Respiratory ordered phase encoding (ROPE): a method for reducing respiratory motion artefacts in MR imaging. , 1985, Journal of computer assisted tomography.

[6]  Armando Manduca,et al.  Autofocusing of Clinical Shoulder MR Images for Correction of Motion Artifacts , 1998, MICCAI.

[7]  D Atkinson,et al.  Automatic compensation of motion artifacts in MRI , 1999, Magnetic resonance in medicine.

[8]  J. Schenck.  The role of magnetic susceptibility in magnetic resonance imaging: MRI magnetic compatibility of the first and second kinds. , 1996, Medical physics.

[9]  F. A. Seiler,et al.  Numerical Recipes in C: The Art of Scientific Computing , 1989 .

[10]  R. Ordidge,et al.  Correction of motional artifacts in diffusion-weighted MR images using navigator echoes. , 1994, Magnetic resonance imaging.

[11]  H. Hricak,et al.  Magnetic resonance imaging with respiratory gating: techniques and advantages. , 1984, AJR. American journal of roentgenology.

[12]  Bob S. Hu,et al.  Fast Spiral Coronary Artery Imaging , 1992, Magnetic resonance in medicine.

[13]  R C Grimm,et al.  The shoulder: adaptive motion correction of MR images. , 1997, Radiology.

[14]  S J Riederer,et al.  Real‐time adaptive motion correction in functional MRI , 1996, Magnetic resonance in medicine.

[15]  S J Riederer,et al.  Interleaved echo planar imaging on a standard MRI system , 1994, Magnetic resonance in medicine.

[16]  S. Riederer,et al.  Navigator-echo-based real-time respiratory gating and triggering for reduction of respiration effects in three-dimensional coronary MR angiography. , 1996, Radiology.

[17]  X Hu,et al.  Retrospective estimation and correction of physiological artifacts in fMRI by direct extraction of physiological activity from MR data , 1996, Magnetic resonance in medicine.

[18]  J. Felmlee,et al.  Orbital navigator echoes for motion measurements in magnetic resonance imaging , 1995, Magnetic resonance in medicine.

[19]  Todd S. Sachs,et al.  The diminishing variance algorithm for real‐time reduction of motion artifacts in MRI , 1995, Magnetic resonance in medicine.

[20]  J A Derbyshire,et al.  Virtual frequency encoding: Achieving symmetry in k‐space , 1998, Magnetic resonance in medicine.