Real-time evaluation of microwave ablation based on the combination of near-infrared spectroscopy technology and shear wave elastography technology

In the clinical treatment of tumors using microwave ablation (MWA), although temperature can be used as an important reference index for evaluating the curative effect of MWA, it cannot fully reflect the biological activity status of tumor tissue during MWA. Finding multi-parameter comprehensive evaluation factors to achieve real-time evaluation of therapeutic effects has become the key for precise ablation. The near-infrared spectroscopy and optical parameters (absorption coefficient (μα), reduced scattering coefficient (μ's), etc.) of biological tissues also change dynamically due to changes in cell morphology and protein tertiary structure during tissue thermal damage. Real-time measurement of the optical parameters of tumor during MWA can be achieved by using minimally invasive function near-infrared spectroscopy. MWA of tumor is essentially a process of protein denaturation and gradual coagulation. During the process of coagulation, the tissue hardness (which could be reflected by Young's modulus, E) also changes in real time. Shear wave elastography can measure Young's modulus in real-time and obtain 2D image. This paper focuses on the real-time evaluation of MWA based on reduced scattering coefficient and Young's modulus. The MWA experiment was conducted on porcine liver in vitro, the two-parameter simultaneous acquisition system was designed to obtain the μ's and E of the liver during MWA. After measuring the μ's and E of different zones after ablation, combining the parameter changes during the ablation and the analysis of the cell activity of the liver after ablation, an evaluation model was established.