Integration of single-fiber reflectance spectroscopy into ultrasound-guided endoscopic lung cancer staging of mediastinal lymph nodes

We describe the incorporation of a single-fiber reflectance spectroscopy probe into the endoscopic ultrasound fine-needle aspi- ration EUS-FNA procedure utilized for lung cancer staging. A math- ematical model is developed to extract information about the physi- ological and morphological properties of lymph tissue from single- fiber reflectance spectra, e.g., microvascular saturation, blood volume fraction, bilirubin concentration, average vessel diameter, and Mie slope. Model analysis of data from a clinical pilot study shows that the single-fiber reflectance measurement is capable of detecting differ- ences in the physiology between normal and metastatic lymph nodes. Moreover, the clinical data show that probe manipulation within the lymph node can perturb the in vivo environment, a concern that must be carefully considered when developing a sampling strategy. The data show the feasibility of this novel technique; however, the poten- tial clinical utility has yet to be determined. © 2010 Society of Photo-Optical