Rationale and objectives: For diagnosis, preoperative planning and postoperative guides, an accurate estimate of joint kinematics is required. It is important to acquire joint motion actively with real-time protocols.

Materials and methods: We bring together MRI developments and new image processing methods in order to automatically extract active bone kinematics from multi-slice real-time dynamic MRI. We introduce a tracking algorithm based on 2D/3D registration and a procedure to validate the technique by using both dynamic and sequential MRI, providing a gold standard bone position measurement.

Results: We present our technique for optimizing jointly the tracking method and the acquisition protocol to overcome the trade-off in acquisition time and tracking accuracy. As a case study, we apply this methodology on a human hip joint.

Conclusion: The final protocol (bFFE, TR/TE 3.5/1.1 ms, Flip angle 80°, pixel size 4.7 × 2.6 mm, partial Fourier reduction factor of 0.65 in read direction, SENSE acceleration factor of 2, frame rate = 6.7 frames/s) provides sufficient morphological data for bone tracking to be carried out with an accuracy of 3° in terms of joint angle.

Title	Published in	Access level	OA Policy	Year	Views	Downloads

Bone Motion Analysis From Dynamic MRI: Acquisition and Tracking	Academic radiology			2005	95	0

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Gilles, Benjamin