Bone Microstructure Evaluation by Photoacoustic Time-frequency Spectral Analysis

In this work, the feasibility of photoacoustic time-frequency spectral analysis (PA- TFSA) for bone microstructure evaluation was investigated. In order to get the main frequency component at each moment, the parameter “power-weighted mean frequency (PWMF)” was used to quantify the frequency spectrum of bone PA signals at each moment. The simulations on bone samples with different mean trabecular thickness (MTT) and ex vivo experiments on rabbit distal femoral metaphysis before and after treatment using ethylenediaminetetraacetic acid (EDTA) solution were conducted. Both the results show that there are higher frequency components in the photoacoustic time frequency spectrum (PA- TFS) as the MTT decreases. The photoacoustic parameters, the maximal PWMF and the averaged PWMF within 1 µs are related to the size characteristics of the trabecular bone, and show significant statistical differences (p<0.01). The results demonstrate that the PA- TFSA has a great potential for clinical assessment of bone health.