Correcting magnetic resonance k-space data for in-plane motion using an optical position tracking system.
OBJECTIVE
Motion is a major confound of image quality in MRI. A method of retrospectively correcting the effects of rotations and translations on the acquired k-space data is presented.


METHODS
In two phantom experiments of well-controlled translation and rotation, two MRI-compatible infrared cameras recorded motion data that were used subsequently to correct the position and phase of recorded k-space samples. Motion data can be acquired with a temporal resolution of 60 Hz and spatial accuracy of 0.1 mm for translations and 0.2 degree for rotations.


RESULTS
Significant improvements of image quality are demonstrated.


CONCLUSIONS
The key advantages of the technique are that it is easy to implement, does not interfere with or complicate MR data acquisition, and is capable of correcting distortions within a single slice. Therefore, the technique has the potential to improve upon approaches that rely on the registration or realignment of successive imaging slices.
Marxen
M
M
Rotman Research Institute, Baycrest Centre for Geriatric Care, Toronto, Ontario M6A 2E1, Canada. mmarxen@rotman-baycrest.on.ca
Marmurek
J
J
Baker
N
N
Graham
S J
SJ
D016477:Artifacts; D002138:Calibration; D007259:Infrared Rays; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009068:Movement; D055620:Optical Phenomena; D019047:Phantoms, Imaging; D012399:Rotation