Feasibility of Laser Speckle-Based Perfusion Imaging in an Ex-Vivo Liver Model

Objective: Advancing microcirculatory perfusion assessment methods is crucial for evaluating organ status during ex-vivo organ preservation and expanding the donor pool. This study demonstrates the feasibility of microcirculatory perfusion imaging in an ex-vivo liver model under normothermic machine perfusion, using two non-contact imaging techniques: laser Doppler perfusion imaging (LDPI) and laser speckle contrast imaging (LSCI).Methods and procedures: An ex-vivo porcine liver was perfused with oxygenated blood for 3 hours. Blood samples were collected every 30 minutes from the hepatic artery and portal vein to evaluate the liver’s overall status. Each of the five liver lobes was imaged every 15 minutes using both the in-house developed LDPI and wireless LSCI devices. Temporally averaged perfusion maps were analyzed to assess spatiotemporal blood flow. Then, correlations between LDPI and LSCI perfusion indices were evaluated.Results: Spatiotemporal perfusion images showed detailed superficial microcirculatory perfusion across five imaged lobes. High correlations between LDPI and LSCI indices were observed in lobes $3-5$ ( ${R}^{2}=0.81$ ), which were well-perfused. Blood lactate levels increased over time, indicating a shift in metabolic activity due to ischemia. Also, correlation of LSCI perfusion indices with pH ( ${R}^{2}_{\max .}=0.95$ ) was observed.Conclusion: The ex-vivo liver model mimics in-vivo perfusion under controlled experimental conditions. LDPI and LSCI provide rapid, independent assessments of local microcirculatory blood flow, demonstrate a high inter-technique correlation, and reflect the overall deterioration of liver status, as evidenced by blood gas parameters.Significance: A compact, wireless LSCI system—validated against LDPI—enables non-invasive evaluation of microcirculatory status and serves as a complementary tool for assessing deep tissue viability. Clinical and Translational Impact Statement—We introduce a wireless, compact, and non-contact LSCI system (validated by LDPI) enabling microcirculatory assessment during machine perfusion, complementing deep tissue medical imaging methods and blood gas analysis to enhance organ viability evaluation and support pre-transplantation treatment decisions (Category: Pre-Clinical Research).