Quantitative assessment of thrombosis-induced blood oxygenation change in deep tissues based on photoacoustic tomography: an ex vivo study.

The staging and classification of thrombosis hold significant clinical value for optimizing thrombus treatment strategies. In this study, we propose a quantitative method based on photoacoustic tomography for assessing thrombosis in deep tissues. By using inner chromophore signals as a correction factor, this approach minimizes the 'spectral coloring' effects caused by overlying heterogeneous tissues. Ex vivo experiments validate that the method acquires accurate spectra up to a depth of 30 mm across various tissue conditions. After calibration, the Pearson correlation coefficients calculated for the spectrum in deep tissue against the uncolored absorption spectrum is 15% higher, and the standard deviation of the Pearson correlation coefficients decreased by 58%. Sequential measurements capture time-dependent spectral changes of thrombus phantom during six days, providing a potential diagnostic reference for thrombus formation time and type. This method offers a non-invasive, practical tool for accurately quantifying thrombosis stages, which might be valuable for optimizing treatment strategies.