In Vivo Noninvasive Imaging of Healthy Lower Lip Mucosa: A Correlation Study between High-Definition Optical Coherence Tomography, Reflectance Confocal Microscopy, and Histology
Table 3
Reflectance confocal microscopy, high-definition optical coherence tomography, and conventional histology morphological characteristics in lip mucosa according to tissue depth.
Reference mark
Depth
RCM characteristics
HD-OCT “en-face” characteristics
Histology
Z0
0 m
Highly scattering homogenous
Highly scattering homogenous layer
Nonhomogenously parakeratinized
Z1
4.96 m
Cytoplasmic granular appearance
Granular appearance and high scattering
Wanting granular layer. Cells appear very eosinophilic, thin and flat. Narrow intercellular spaces
Z2
29.79 m
Cytoplasmic border becomes apparent
Cytoplasmic granular appearance and areas with honeycomb pattern
Cells and nuclei become flat and irregularly shaped. Nuclei acquire pyknotic appearance
Z3
84.36 m
Wider honeycomb pattern. May be difficult to clearly distinguish nuclei. Dermal papillae may start becoming visible
Dermal papillae may start becoming visible
In the prickle layer, cells appear round or polygonal. Nuclei seem intensely basophilic and centrally located
Z4
124.00 m
Loss of honeycomb pattern. Nuclei become dark and are not clearly distinguished
Dermal papillae
Basal cell layer cells have a cuboidal shape containing large rounded nuclei. Mitotic activity can be easily distinguished
Z5
173.00 m
Epithelial junction, ill-defined papillae and collagen fibers
Transitional epithelium
Z6
193.69 m
Collagen fibers
Collagen fibers
Loose connective tissue with a rich vascular supply. The deeper layers contain heavy bundles of collagen fibers