Photoacoustic power azimuth spectrum for microvascular evaluation

Mengjiao Zhang; Yingna Chen; Weiya Xie; Shiying Wu; Jiangnan Liao; Qian Cheng

doi:10.1016/j.pacs.2021.100260

Photoacoustic power azimuth spectrum for microvascular evaluation

Photoacoustics. 2021 Mar 10:22:100260. doi: 10.1016/j.pacs.2021.100260. eCollection 2021 Jun.

Authors

Mengjiao Zhang^{1

2}, Yingna Chen¹, Weiya Xie¹, Shiying Wu¹, Jiangnan Liao¹, Qian Cheng^{1

2}

Affiliations

¹ Institute of Acoustics, School of Physics Science and Engineering, Tongji University, Shanghai, PR China.
² The Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration, Ministry of Education, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, Shanghai, PR China.

Abstract

The tubular structures and dendritic distributions of blood vessels emit anisotropic photoacoustic (PA) signals with different intensities and frequency components at different angles. Therefore, spectral analysis of PA signals from a single angle cannot accurately determine the physical characteristics of microvessels. This study investigated the feasibility of using the PA power azimuth spectrum (PA-PAS) method to evaluate microvessel structures. We mapped the acoustic power spectrum of the PA signals along the azimuth direction. Based on a frequency-domain analysis of the broadband PA signal, we calculated the spectral parameter power-weighted mean frequency (PWMF). The results demonstrate that the PA signal information of the microvessel is mainly concentrated in the direction of its width. In addition, the PWMF decreases linearly with the microvascular size. The experimental findings exhibit good agreement with the simulation results, thus demonstrating that this approach can effectively differentiate the sizes of microvessels.

Keywords: Angle-dependent frequency analysis; Microvascular evaluation; PA power azimuth spectrum; Size; Structural direction.