Abstract

Photoacoustic (PA) spectroscopy is considered to be one of the most effective ways to measure the levels of hematocrit ($H$) and oxygenation saturation (${{\rm SO}_2}$) of blood, which are essential for diagnosing blood-related illnesses. This simulation study aims to investigate the impact of individual optical parameters, i.e., optical absorption coefficient (${\mu _a}$), scattering coefficient (${\mu _s}$), and anisotropy factor ($g$), on the accuracy of this technique in estimating the blood properties. We first performed the Monte Carlo simulations, using realistic optical parameters, to obtain the fluence maps for various samples. The wavelengths of the incident light were chosen to be 532, 700, 1000, and 1064 nm. Thereafter, the ${k}$-Wave simulations were executed, incorporating those fluence maps to generate the PA signals. The blood properties were obtained using the PA signals. We introduced variations in ${\mu _a}$, ${\mu _s}$, and $g$ ranging from ${-}{10}\%$ to ${+}{10}\%$, ${-}{10}\%$ to ${+}{10}\%$, and ${-}{5}\%$ to ${+}{1}\%$, respectively, at 700 and 1000 nm wavelengths. One parameter, at both wavelengths, was changed at a time, keeping others fixed. Subsequently, we examined how accurately the blood parameters could be determined at physiological hematocrit levels. A 10% variation in ${\mu _a}$ induces a 10% change in $H$ estimation but no change in ${{\rm SO}_2}$ determination. Almost no change has been seen for ${\mu _s}$ variation. However, a 5% (${-}{5}\%$ to 0%) variation in the $g$ factor resulted in approximately 160% and 115% changes in the PA signal amplitudes at 700 and 1000 nm, respectively, leading to ${\approx} 125\%$ error in hematocrit estimation and ${\approx} 14\%$ deviation in ${{\rm SO}_2}$ assessment when nominal ${{\rm SO}_2} = 70\%$. It is clear from this study that the scattering anisotropy factor is a very sensitive parameter and a small change in its value can result in large errors in the PA estimation of blood properties. In the future, in vitro experiments with pathological blood (inducing variation in the $g$ parameter) will be performed, and accordingly, the accuracy of the PA technique in quantifying blood $H$ and ${{\rm SO}_2}$ will be evaluated.

© 2024 Optica Publishing Group

Validation of photoacoustic/ultrasound dual imaging in evaluating blood oxygen saturation

Sirui Liu, Rui Zhang, Tao Han, Yinhao Pan, Guangjie Zhang, Xing Long, Chenyang Zhao, Ming Wang, Xuelan Li, Fang Yang, Yuchao Sang, Lei Zhu, Xujin He, Jianchu Li, Yewei Zhang, Changhui Li, Yuxin Jiang, and Meng Yang
Biomed. Opt. Express 13(10) 5551-5570 (2022)

Single-stage approach for estimating optical parameters in spectral quantitative photoacoustic tomography

Miika Suhonen, Aki Pulkkinen, and Tanja Tarvainen
J. Opt. Soc. Am. A 41(3) 527-542 (2024)

Empirical model functions to calculate hematocrit-dependent optical properties of human blood

Martina Meinke, Gerhard Müller, Jürgen Helfmann, and Moritz Friebel
Appl. Opt. 46(10) 1742-1753 (2007)

Toward assessment of blood oxygen saturation by spectroscopic optical coherence tomography

Dirk J. Faber, Egbert G. Mik, Maurice C.G. Aalders, and Ton G. van Leeuwen
Opt. Lett. 30(9) 1015-1017 (2005)

Simultaneous assessment of red blood cell aggregation and oxygen saturation under pulsatile flow using high-frequency photoacoustics

Tae-Hoon Bok, Eno Hysi, and Michael C. Kolios
Biomed. Opt. Express 7(7) 2769-2780 (2016)