Calibration and validation scheme for in vivo spectroscopic imaging of tissue oxygenation
Maritoni A. Litorja, Robert C. Chang, Jeeseong Hwang, David W. Allen
The determination of the level of oxygenation in optically accessible tissues using multispectral or hyperspectral imaging (HSI ) of oxy- and deoxyhemoglobin has special appeal in clinical work due to its non-invasiveness, ease of use and capability of providing molecular and anatomical information at near video rates during surgery. In this paper we refer to an example of the use of HSI in monitoring oxygenation of kidneys during partial nephrectomy. In a study using pigs, it was found that artery-only clamping left the kidney better oxygenated, as opposed to clamping both the artery and the vein. A subsequent study correlates gradations in partial blood flow during the surgical procedure with post-operative renal function via assessment of creatinine level. We discuss the various contribu-tions to the uncertainty of the oxygen saturation measured by this medical remote sensing imaging technique and the methods of their evaluation.