PROSPECTIVE HEAD MOVEMENT CORRECTION FOR HIGH-RESOLUTION MRI USING AN IN-BORE OPTICAL TRACKING SYSTEM

Abstract

In MRI of the human brain, subject motion is a major cause of magnetic resonance image quality degradation. To compensate the effects of head motion during data acquisition, an in-bore optical motion tracking system is proposed. The system comprises one or two MR compatible infrared cameras that are fixed on a holder right above and in front of the head coil. The resulting close proximity of the cameras to the object allows precise tracking of its movement. During image acquisition, the MRI scanner uses this tracking information to prospectively compensate for head motion by adjusting gradient field direction and RF phase and frequency. Experiments performed on subjects demonstrate the system's robustness, exhibiting an accuracy of better than 0.1mm and 0.15˚.