Hyperspectral imaging of human liver allografts for prediction of initial graft function.

Purpose: Ischemia reperfusion injury represents a significant yet difficult to assess risk factor for short- and long-term graft impairment in human liver transplantation (LT). As a non-invasive, non-ionizing tool, hyperspectral imaging (HSI) is capable of correlating optical properties with organ microperfusion. Hence, we here performed a study of human liver allografts assessed by HSI for microperfusion and prediction of initial graft function.

Methods: Images of liver parenchyma of 37 human liver allografts were acquired at bench preparation, during normothermic machine perfusion (NMP), if applicable, and after reperfusion in the recipient. A specialized HSI acquisition software computed oxygen saturation (StO2), tissue hemoglobin indices (THI), near infrared perfusion indices (NIR), and tissue water indices (TWI). HSI parameters were analyzed for differences with regard to preservation technique, reperfusion sequence and presence of early allograft dysfunction (EAD).

Results: Organ preservation was performed by means of NMP (n = 31) or static cold storage (SCS; n = 6). Patients' demographics, donor characteristics, presence of EAD (NMP 36.7% vs. SCS 50%, p = 0.6582), and HSI parameters were comparable between both groups of preservation method. In organs developing EAD, NIR at 1, 2, and 4 h NMP and after reperfusion in the recipient was significantly lower (1 h NMP: 18.6 [8.6-27.6] vs. 28.3 [22.5-39.4], p = 0.0468; 2 h NMP: 19.4 [8.7-30.4] vs. 37.1 [27.5-44.6], p = 0.0011; 4 h NMP: 26.0 [6.8-37.1] vs. 40.3 [32.3-49.9], p = 0.0080; reperfusion: 13.0 [11.5-34.3] vs. 30.6 [19.3-44.0], p = 0.0212).

Conclusion: HSI assessment of human liver allografts is feasible during organ preservation and in the recipient. NIR during NMP and after reperfusion might predict the onset of EAD. Larger trials are warranted for assessment of this novel technique in human LT.