1. Center for Fast Ultrasound Imaging Department of Electrical Engineering Using Phased Array for Transverse Oscillation Vector Velocity Imaging Michael Johannes Pihl 1, Per Haugaard 2, and Jørgen Arendt Jensen 1 1 Center for Fast Ultrasound Imaging, Building 349 Department of Electrical Engineering Technical University of Denmark 2 Bk Medical, Mileparken 34, 2730 Herlev Denmark EUROSON 2010 Copenhagen, August 22 nd -25 th, 2010

2. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Recap from previous talks Vector velocity imaging Shallow depths (< 3-4 cm) QUESTIONS: Can we get further down? Can we scan the heart?

3. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Outline Simple principle TO setup for phased array Simulation setup Simulation results Conclusion

4. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Principle of transverse oscillation (TO) Axial direction Transverse direction

5. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Principle of transverse oscillation (TO)

6. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark TO beamforming

7. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Phased array setup Phased array Image area TO lines 2 TO lines –Fixed angle –>Spacing increases

8. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Simulation tool

9. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Simulation setup Transducer (Phased array) Elements128 Pitch0.220 mm Center freq.3.5 MHz System Pulse rep. freq.5 kHz No. shots per est.64 Blood Angle 90 degrees Speed1 m/s Radius5 mm

10. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Simulation results 10 cm Relative bias: 2.6% Relative std: 6.5% 20 realizations

11. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Simulation results 15 cm Relative bias: 4.2% Relative std: 8.5% 20 realizations

12. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Conclusion and perspectives In simulation: Measure velocities at to 10-15 cm Potential for getting that far down in clinical in- vivo measurements Clinical perspectives –Insufficient heart valves –AAAs Further development –Through simulations –Through measurements –3D vector velocity imaging

13. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Acknowledgements This work was supported by the Advanced Technology Foundation and B-K Medical Aps.

14. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Thank you for your attention Questions?

15. Center for Fast Ultrasound Imaging, Department of Electrical Engineering Technical University of Denmark Clinical potential Vector velocity imaging –Insufficient valves (in the heart) –Abdominal aortic aneurisms –Portal vein –Renal artery Multigating –Velocity and angle at every pixel Develop new quantitative measures