1. 10-6-2015 Delft University of Technology Abdominal Wall Vibration Analysis for Evaluation of Biomechanical Properties and Physiological Diagnosis of Internal Abdomen Final MSc presentation Teunis Schuurman Department of Precision and Microsystems Engineering Supervisors: Prof. Dr. Ir. Daniel Rixen Dr. Jan-Willem Hinnen Dr. Ir. Cees Swenne

2. Final MSc. presentation2

3. Final MSc. presentation3 Contents: Introduction; Measurement setup; Data processing techniques; Results; Conclusion; Future Work & recommendations. Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

4. Final MSc. presentation4 Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

5. Final MSc. presentation5 Goal Evaluate the use of vibration analysis to assess the biomechanical properties of internal abdomen Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

6. Final MSc. presentation6 Largest and most cramp human body cavity. Contains stomach, liver, intestines, kidneys, abdominal aorta, vena cava, etc. Organs suspended freely in peritoneum. Accessible for physical Examination. Human Abdomen Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

7. Final MSc. presentation7 [1] http://en.wiktionary.org, 2011 http://en.wiktionary.org [2] Ferguson, 1990 Abdomen Examination Physical Examination Palpation: “Feeling or pushing to determine medical condition as the normality of organs or the presence or absence of tumors, swelling, muscle tension, etc” [1], [2] Auscultation, listen for sounds Percussion: “ “The tapping of the body to asses underlying structures” [1], [2] Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

8. Final MSc. presentation8 Abdomen Examination Based on change in `feel’, identifying: Rigidities; Unusual sliding friction; Unusual masses pulsation sources } mechanical properties } dynamic properties Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

9. Final MSc. presentation9 Influence on dynamics Vibration: “ Periodic process around an equilibrium position” [1] Undamped: Damped: [1 http://en.wiktionary.org/, 2011 http://en.wiktionary.org/ Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations Amplitude Frequency [rad/s] Damping

10. Final MSc. presentation10 Influence on dynamics Rigidity  stiffness k Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations m k

11. Final MSc. presentation11 Influence on dynamics Mass distribution  mass m Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations m k

12. Final MSc. presentation12 Influence on dynamics Friction  damping c Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations m k c

13. Final MSc. presentation13 Influence on dynamics Excitation source x(t): forced vibrations Transfer function Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations m k c x(t) y(t)

14. Final MSc. presentation14 Abdominal Vibration systems Abdominal cavity as a mechanical system Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

15. Final MSc. presentation15 Digestive track Bowel sounds Peaking above 100 Hz [4] Respiration Large Amplitude Low frequency [0.1 – 0.2 Hz] Respiratory sounds: [+ 150 Hz] [3] Cardiac cycle Heartbeat freq [1 – 2 Hz] Expansion of heart; Dilation of arteries [Abdominal Aorta: 2 – 20 %] [5] Abdominal Vibration systems Excitation sources Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations [3] Dellinger et al, 2008 [4] Politzer, 1976 [5] Son, 1993

16. Final MSc. presentation16 Abdominal Vibration systems Summarized: Physiological Examination assesses mechanical properties; Mechanical properties influence dynamics Excitation sources present in abdomen, dynamics in abdomen expected Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

17. Final MSc. presentation17 Measurement setup Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

18. Final MSc. presentation18 Abdominal Vibration measurements Vibration measurement: Uses Doppler effect on light Easy Setup Large frequency & velocity range Velocity of surface less influenced by respiration. Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

19. Final MSc. presentation19 Single beam measurement One beam = one measurement Approximate parallel scan with triggered sequential scan Abdominal Vibration measurements Measurement setup Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations t = 1t = 2 t = 3t = 4

20. Final MSc. presentation20 Abdominal Vibration measurements Measurement setup LDV measures skin velocity ECG monitor triggers on QRS complex Subject positioned supine to relax abdominal wall Reflective stickers to improve signal quality Some measurement performed with Finometer, measuring `input’ bloodpressure waveform Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

21. Final MSc. presentation21 Abdominal Vibration measurements Measurement setup Vibration pattern synchronizes with cardiac cycle Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

22. Final MSc. presentation22 Data processing techniques Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

23. Final MSc. presentation23 Instantanous Deflection Surface Plot parallel approximation S(t): Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

24. Final MSc. presentation24 Individual velocity profiles Plot individual velocity profiles and assess in regard to their position on the abdominal surface Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

25. Final MSc. presentation25 Frequency Response Function Transfer function H(f) between input x(t) and output signal y(t) Input: blood pressure waveform dP/dt Output: velocity signal Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

26. Final MSc. presentation26 Results Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

27. Final MSc. presentation27 Results Vibration of abdominal wall contains repeatable patterns in synchronization with cardiac cycle; LDV is able to detect them, using an ECG as trigger and retro-reflective stickers to improve returned signal power; Clear pulsation shown above Abdominal Aorta, other locations more complex Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

28. Final MSc. presentation28 Conclusion Abdominal wall shows repeatable vibration patterns dominated by cardiac activity. Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

29. Final MSc. presentation29 Future work & recommendations Future work: A patent application has filed yesterday If granted, expected TU will continue research. Publication of article discussing results of research on short term. Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

30. Final MSc. presentation30 Future work Recommendations: Implement respiration tracking Improve reflection reflective clothing, non-health risky spray coatings) Use light frequencies with improved reflection properties Implement parallel scanning Multi-beam LDV systems, photogrammetry Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

31. Final MSc. presentation31 Future work Recommendations: Increase number of volunteers Check for inter-patient variability; Observe intra-patient variability in other subjects; Investigate origin of the more complex vibration profiles Increased velocity amplitudes observed in AAA patients increased pulse pressures, reduction in artery stiffness patient-specific anatomy? Introduction Meas. setup Data proc. techn. Results Conclusion Future Work & recommendations

32. Final MSc. presentation32 Thank you for your attention!

33. Final MSc. presentation33 Frequency domain analysis Identification of major frequency components Introduction Meas. setup Data proc. techn. Results Conclusion

34. Final MSc. presentation34 Frequency – time domain Non-steady frequency analysis: Continous Wavelet Transform Mexican hat Wavelet Pseudo-freq

35. Final MSc. presentation35 Frequency Response Function Transfer function between input x(t) and output signal y(t)

36. Final MSc. presentation36 Measurement methods Vibration measurements on abdominal wall Accelerometers [a] Photogrammetry [b] Laser Doppler Vibrometry [c] [a] www.sensorsmag.com, 2011www.sensorsmag.com [b] www.gom.com, 2010www.gom.com [c] www.polytec.de, 2010www.polytec.de

37. Final MSc. presentation37 Respiration

38. Final MSc. presentation38 Respiration Organ motion

39. Final MSc. presentation39 LDV operation principle

40. Final MSc. presentation40 Signal quality

41. Final MSc. presentation41 Reflective stickers Air – skin: 4 – 7 % light reflection; Epidermis:mostly transmitting, UV absorbed; Dermis:600 – 1300 nm penetrates deep back scattering due to micro-structures

42. Final MSc. presentation42 ECG monitor Muscle contract after small drop en rice of electric potential on cell membranes; Heart contraction causes fluctuating electric field ECG leads measures the changes 3 lead ECG 12 lead ECG

43. Final MSc. presentation43 Spectral Leakage Using sampling and discrete Fourier transform causes spectral leakage

44. Final MSc. presentation44 Spectral Leakage Using sampling and discrete Fourier transform causes spectral leakage Rectangular window (blue) Tukey (r = 0.5) window (cyan) The Hann (green) window Blackman-Harris (red) window Flat-Top (magenta) window