An embedded optical tracking system for motion-corrected magnetic resonance imaging at 7T.
OBJECTIVE
Prospective motion correction using data from optical tracking systems has been previously shown to reduce motion artifacts in MR imaging of the head. We evaluate a novel optical embedded tracking system.


METHODS
The home-built optical embedded tracking system performs image processing within a 7 T scanner bore, enabling high speed tracking. Corrected and uncorrected in vivo MR volumes are acquired interleaved using a modified 3D FLASH sequence, and their image quality is assessed and compared.


RESULTS
The latency between motion and correction of the slice position was measured to be (19 ± 5) ms, and the tracking noise has a standard deviation no greater than 10 μm/0.005° during conventional MR scanning. Prospective motion correction improved the edge strength by 16 % on average, even though the volunteers were asked to remain motionless during the acquisitions.


CONCLUSIONS
Using a novel method for validating the effectiveness of in vivo prospective motion correction, we have demonstrated that prospective motion correction using motion data from the embedded tracking system considerably improved image quality.
Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstrasse 1a, 04103 Leipzig, Germany. jschulz@cbs.mpg.de
Jessica
J
Schulz
Thomas
T
Siegert
Enrico
E
Reimer
Christian
C
Labadie
Julian
J
Maclaren
Michael
M
Herbst
Maxim
M
Zaitsev
Robert
R
Turner
D000465:Algorithms; D001921:Brain / Q000473:pathology; D002138:Calibration; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015233:Models, Statistical; D009038:Motion; D055096:Optical Devices; D055095:Optics and Photonics / Q000379:methods*; D019047:Phantoms, Imaging; D013997:Time Factors