Collagen Organization in Second Harmonic Generation Images for the Assessment of Thyroid Nodule Capsular Invasion

Abstract

Second harmonic generation (SHG) microscopy is an imaging technique which enables the visualization of collagen architecture within tissue samples. Going beyond simple intensity, an extension of SHG microscopy involves the acquisition of polarization dependent image stacks which are further processed with theoretical collagen models to provide quantitative information for the collagen structure and architecture. We use SHG microscopy images for the visualization of the collagen distribution in thyroid nodule capsules. More precisely, we are interested in capsular invasion, a hallmark of follicular carcinoma and a method for evaluating possible lymph node metastasis in the case of papillary thyroid carcinoma. Different image processing methods are used to assess the collagen organization which is further related to possible invasion sites in the thyroid nodule capsule.