Prospective real-time head motion correction using inductively coupled wireless NMR probes.
OBJECTIVE
Head motion continues to be a major source of artifacts and data quality degradation in MRI. The goal of this work was to develop and demonstrate a novel technique for prospective, 6 degrees of freedom (6DOF) rigid body motion estimation and real-time motion correction using inductively coupled wireless nuclear magnetic resonance (NMR) probe markers.


METHODS
Three wireless probes that are inductively coupled with the scanner's RF setup serve as fiducials on the subject's head. A 12-ms linear navigator module is interleaved with the imaging sequence for head position estimation, and scan geometry is updated in real time for motion compensation. Flip angle amplification in the markers allows the use of extremely small navigator flip angles (∼1°). A novel algorithm is presented to identify marker positions in the absence of marker specific receive channels. Motion correction is demonstrated in high resolution 2D and 3D gradient recalled echo experiments in a phantom and humans.


RESULTS
Significant improvement of image quality is demonstrated in phantoms and human volunteers under different motion conditions.


CONCLUSIONS
A novel real-time 6DOF head motion correction technique based on wireless NMR probes is demonstrated in high resolution imaging at 7 Tesla.
Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
Saikat
S
Sengupta
Sasidhar
S
Tadanki
John C
JC
Gore
E Brian
EB
Welch
D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D003199:Computer Systems; D004867:Equipment Design; D019544:Equipment Failure Analysis; D057918:Fiducial Markers; D019416:Head Movements; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D008280:Magnetics / Q000295:instrumentation*; D008297:Male; D008904:Miniaturization; D009038:Motion; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D059015:Wireless Technology / Q000295:instrumentation*
inductively coupled probes; prospective rigid body motion correction; wireless NMR markers