Functional Photoacoustic and Ultrasonic Assessment of Osteoporosis: A Clinical Feasibility Study

Abstract

Objective and Impact Statement. To study the feasibility of combined functional photoacoustic (PA) and quantitative ultrasound (US) for diagnosis of osteoporosis in vivo based on the detection of chemical and microarchitecture (BMA) information in calcaneus bone. Introduction. Clinically available X-ray or US technologies for the diagnosis of osteoporosis do not report important parameters such as chemical information and BMA. With unique advantages, including good sensitivity to molecular and metabolic properties, PA bone assessment techniques hold a great potential for clinical translation. Methods. By performing multiwavelength PA measurements, the chemical information in the human calcaneus bone, including mineral, lipid, oxygenated-hemoglobin, and deoxygenated-hemoglobin, were assessed. In parallel, by performing PA spectrum analysis, the BMA as an important bone physical property was quantified. An unpaired t-test and a two-way ANOVA test were conducted to compare the outcomes from the two subject groups. Results. Multiwavelength PA measurement is capable of assessing the relative contents of several chemical components in the trabecular bone in vivo, including both minerals and organic materials such as oxygenated-hemoglobin, deoxygenated-hemoglobin, and lipid, which are relevant to metabolic activities and bone health. In addition, PA measurements of BMA show good correlations (R2 up to 0.65) with DEXA. Both the chemical and microarchitectural measurements from PA techniques can differentiate the two subject groups. Conclusion. The results from this initial clinical study suggest that PA techniques, by providing additional chemical and microarchitecture information relevant to bone health, may lead to accurate and early diagnosis, as well as sensitive monitoring of the treatment of osteoporosis.

Wavelet transform-based photoacoustic time-frequency spectral analysis for bone assessment

“…To compensate for the strong acoustic attenuation, we can use a dual backscattered US and PA system for measuring the acoustic propagation attenuation in human cancellous bone. The backscattered PA modality is used to measure the size of the trabecular bone, while the backscattered US modality is used for US attenuation compensation [ 24 ]. Second, both bone mineral and hemoglobin contribute to strong absorption at a wavelength of 690 nm.…”

“…Thermal PA measurements can provide the information associated with BMD, based on the dependence of the PA signal intensity on temperature [ 23 ]. Multi-wavelength PA measurements can access the microstructure and relative contents of several chemical components in calcaneus bones in vivo , including both minerals and organic materials, such as oxygenated-hemoglobin, deoxygenated-hemoglobin, and lipids, which are crucial for metabolic activities and bone health [ 24 ]. PA spectral analysis and 3D PA imaging can be used to assess the bone microstructure information quantitatively [ 25 , 26 ].…”

Bone Chemical Composition Assessment with Multi-Wavelength Photoacoustic Analysis

“…In particular, the mode of detection should be improved based on the target bone in vivo. For example, we used the transmission PA mode for multi-wavelength PA measurement of calcaneus bone in vivo in our recently published study [29]. Fifth, the optical penetration depth at different wavelengths and the ultrasound penetration depth at difference frequencies should be further studied.…”

“…The amplitude of the PA signal generated by the bone after ignoring the reflected acoustic wave from the boundary can be expressed as [29,30]:…”

Bone Chemical Composition Analysis Using Photoacoustic Technique

“…For in vivo study, the bone assessment technique based on the PA detecting method described in our manuscript may be not available and should be optimized with better design. For example, the transmission PA mode for multi-wavelength PA measurement of bone in vivo in our study published recently [38]. In addition, the effects of light attenuation and ultrasound attenuation need to be considered.…”