Multimodal PA/US Imaging for oxygen saturation quantification in human carotid in vivo

Multispectral photoacoustic (PA) analysis is one of the analytical techniques employed in biomedical imaging for various applications, whereby acoustic waves generated by the interaction of multiwavelength lasers are detected by the ultrasound (US) machine. The technique is widely used, for instance, in quantifying oxygen saturation levels in the blood. However, the reliability of the results is of great consequence, as they can significantly impact the efficacy of diagnosis and treatment. Therefore, advances in data calibration and analysis techniques are crucial to achieve more reliable results. In this study, we developed a PA/US system for measuring the oxygen saturation level of blood inside the carotid artery and jugular vein. We applied the preprocessing available for carotid and various data correction methods to quantify the oxygen saturation of the imaged arterial and venous blood. A total of 165 carotids were measured in 117 volunteers, and all data were pooled to show the accuracy of the data calibration and analysis method. The carotid artery showed more consistent oxygen saturation readings of 93.0±3.5% and the internal jugular vein showed 71.3±6.4%. It is anticipated that these results will act as standardized metrics to be referred to in future clinical studies. In turn, this would enhance diagnostic accuracy in the biomedical imaging field, and play an instrumental role in establishing customized treatment plans for patients. The findings of this study will have potential applications in future clinical research and actual medical practice and will support early diagnosis and effective treatment of various diseases through more reliable oxygen saturation measurements.