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Real time prospective motion correction for high resolution in vivo MRI using an optical motion tracking system

: Zaitsev, M.; Dold, C.; Hennig, J.; Speck, O.

International Society for Magnetic Resonance in Medicine -ISMRM-:
ISMRM 14th Scientific Meeting 2006. Proceedings of the International Society for Magnetic Resonance in Medicine : 6 - 12 May 2006, Seattle, Washington
Seattle, 2006
International Society for Magnetic Resonance in Medicine (Scientific Meeting) <14, 2006, Seattle/Wash.>
Conference Paper
Fraunhofer IGD ()
brain imaging; tracking; image quality; infrared based technology; magnetic resonance imaging; MRI

Even small subject motions can degrade the image quality especially in high-resolution MRI. For head imaging the overall imaging time is limited by the subject.s ability to maintain the same head position. This time is on the order of minutes and may be dramatically reduced in a case of pathology. Projection reconstruction(1) or PROPELLER(2) methods are known to be less prone to motion artefacts. The sensitivity of standard 2D and 3D imaging methods to motion may be reduced by use of the navigator echoes, such as orbital (3) or spherical (4) navigator methods. Navigators, however, not only lengthen the measurement, but also require additional excitation RF pulses to be incorporated into the sequence, which disturbs the steady state. Here we demonstrate the possibility of interfacing the MR scanner with an external optical motion tracking system, capable of determining object.s position with sub-millimetre accuracy at high update rate. The proposed approach uses this motion information to update in real time the position of the imaging volume during the acquisition of k-space data. Such methods have previously been proposed for fMRI. The purpose of the study is to evaluate the applicability of prospective motion correction for high-resolution brain imaging in the presence of strong subject motion.