Dynamic X-ray Microtomography vs. Laser-Doppler Vibrometry: A Comparative Study.

Purpose: There are challenges in understanding the biomechanics of the human middle ear, and established methods for studying this system show significant limitations. In this study, we evaluate a novel dynamic imaging technique based on synchrotron X-ray microtomography designed to assess the biomechanical properties of the human middle ear by comparing it to laser-Doppler vibrometry (LDV).

Methods: We examined three fresh-frozen temporal bones (TB), two donated by white males and one by a Black female, using dynamic synchrotron-based X-ray microtomography for 256 and 512 Hz, stimulated at 110 dB and 120 dB sound pressure level (SPL). In addition, we performed measurements on these TBs using 1D LDV, a well-established method.

Results: The normalized displacement values (µm/Pa) at the umbo and the posterior crus of the stapes are consistent or within 5-10 dB differences between all LDV and dynamic microtomography measurements and previously reported literature references. In general, the overall behavior is similar between the two measurement techniques.

Conclusion: In conclusion, our results demonstrate the suitability of dynamic synchrotron-based X-ray microtomography in studying the middle ear's biomechanics. However, this study shows that better standardization regarding acoustic stimulation and measurement points is needed to better compare the two measurement techniques.