Benjamin Schwartz1, Nathan McDannold2,3
1Biophysics, Harvard
University, Boston, MA, United States; 2Radiology, Harvard Medical
School, Boston, MA, United States; 3Radiology, Brigham &
Women's Hospital, Boston, MA, United States
In previous work, our group and others have demonstrated the use of ultrasound measurements for MR motion compensation, in a manner analogous to classic MR navigator echoes. Existing implementations can only measure shifts parallel to the collimated ultrasound beam. We demonstrate an alternative approach that can track motion perpendicular to the beam axis. The new system employs a biometric training stage in which MRI and ultrasound data are acquired simultaneously. We have demonstrated both retrospective and prospective motion compensation in phantoms. Future work include tests for breath motion compensation in animal models and human subjects.