Effect of capsule on surface diffuse refelectance spectroscopy of capsular solid organs (Conference Presentation)

Abstract

Surface diffuse reflectance spectroscopy (DRS) has the potential for real-time, bed-side evaluation of solid donor organs including liver and kidney for transplant. Nilsson et al used an applicator-probe with multiple source-detector paired with a 2.5mm source-detector separation to show that DRS of liver through the capsule represents the DRS of cross-sectional liver; however, a small but consistent difference over 600nm—850nm between DRS with capsule and without capsule was observed. Understanding the effect of the capsule on surface DRS of solid capsular organs is important to accurately resolving subcapsular tissue properties for the evaluation of organ quality. We have developed a portable lab-on-a-crater DRS system with an applicator-probe with 3mm source-detector separation for evaluating human liver and kidney specimens routinely in a pathology lab. The DRS performed on liver with capsule is consistently lower in the spectral intensity between 600-850nm when compared to DRS performed on the cross-section of liver, regardless of the pathology of subcapsular parenchyma. To model the effect of capsule on surface DRS of capsular solid organs like liver, we have implemented an analytical approach based on a master-slave dual-source configuration model (Piao and Patel, App. Opt, 56(5) 1447-1452, 2017). Under the assumption of the capsular layer having lower oxygenated hemoglobin and potentially increased elastin content and by making the location and intensity of the slave-source dependent upon the properties of the capsular layer, the surface DRS predicted by this master-slave dual-source model reveals the measured pattern over 600-850nm between with the capsule and without the capsule.