Contrast of nuclei in stratified squamous epithelium in optical coherence tomography images at 800 nm

TL;DR

This study clarifies the optical scattering properties of keratinocyte nuclei in stratified squamous epithelium using micro-OCT, resolving previous inconsistencies and linking scattering signals to cellular maturation markers.

Contribution

The paper demonstrates that keratinocyte nuclei are generally low scattering in vivo with micro-OCT and explains the origins of high scattering signals, improving optical diagnostic criteria.

Findings

Nuclei are mostly low scattering in vivo at 1.28 μm resolution.

High scattering signals are linked to nuclear flattening and glycogen accumulation.

Insufficient axial resolution may have caused previous misinterpretations.

Abstract

Imaging nuclei of keratinocytes in the stratified squamous epithelium has been a subject of intense research since nucleus associated cellular atypia is the key criteria for the screening and diagnosis of epithelial cancers and their precursors. However, keratinocyte nuclei have been reported to be either low scattering or high scattering, so that these inconsistent reports might have led to misinterpretations of optical images, and more importantly, hindered the establishment of optical diagnostic criteria. We disclose that they are generally low scattering in the core using Micro-optical coherence tomography (micro-OCT) of 1.28 um axial resolution in vivo; those previously reported high scattering or bright signals from nuclei are likely from the nucleocytoplasmic boundary, and the low-scattering nuclear cores were missed possibly due to insufficient axial resolutions (about 4 um). It is further demonstrated that the high scattering signals may be associated with flattening of nuclei and cytoplasmic glycogen accumulation, which are valuable cytologic hallmarks of cell maturation.