Inference of Haemoglobin Concentration From Stereo RGB
This provides a non-invasive, real-time method for monitoring tissue health during surgery, with potential clinical impact, though it is incremental as it builds on existing multispectral imaging techniques.
The paper tackles the problem of estimating total haemoglobin concentration and blood oxygenation in tissue using only RGB images from a stereo laparoscope, achieving robust estimation through a novel decomposition and regularization approach validated on synthetic and in vivo data.
Multispectral imaging (MSI) can provide information about tissue oxygenation, perfusion and potentially function during surgery. In this paper we present a novel, near real-time technique for intrinsic measurements of total haemoglobin (THb) and blood oxygenation (SO2) in tissue using only RGB images from a stereo laparoscope. The high degree of spectral overlap between channels makes inference of haemoglobin concentration challenging, non-linear and under constrained. We decompose the problem into two constrained linear sub-problems and show that with Tikhonov regularisation the estimation significantly improves, giving robust estimation of the Thb. We demonstrate by using the co-registered stereo image data from two cameras it is possible to get robust SO2 estimation as well. Our method is closed from, providing computational efficiency even with multiple cameras. The method we present requires only spectral response calibration of each camera, without modification of existing laparoscopic imaging hardware. We validate our technique on synthetic data from Monte Carlo simulation % of light transport through soft tissue containing submerged blood vessels and further, in vivo, on a multispectral porcine data set.