Semi-automated algorithm for localization of dermal/epidermal junction in reflectance confocal microscopy images of human skin

Abstract

The examination of the dermis/epidermis junction (DEJ) is clinically important for skin cancer diagnosis. Reflectance confocal microscopy (RCM) is an emerging tool for detection of skin cancers in vivo. However, visual localization of the DEJ in RCM images, with high accuracy and repeatability, is challenging, especially in fair skin, due to low contrast, heterogeneous structure and high inter- and intra-subject variability. We recently proposed a semi-automated algorithm to localize the DEJ in z-stacks of RCM images of fair skin, based on feature segmentation and classification. Here we extend the algorithm to dark skin. The extended algorithm first decides the skin type and then applies the appropriate DEJ localization method. In dark skin, strong backscatter from the pigment melanin causes the basal cells above the DEJ to appear with high contrast. To locate those high contrast regions, the algorithm operates on small tiles (regions) and finds the peaks of the smoothed average intensity depth profile of each tile. However, for some tiles, due to heterogeneity, multiple peaks in the depth profile exist and the strongest peak might not be the basal layer peak. To select the correct peak, basal cells are represented with a vector of texture features. The peak with most similar features to this feature vector is selected. The results show that the algorithm detected the skin types correctly for all 17 stacks tested (8 fair, 9 dark). The DEJ detection algorithm achieved an average distance from the ground truth DEJ surface of around 4.7μm for dark skin and around 7–14μm for fair skin.

Remodeling of the Epithelial–Connective Tissue Interface in Oral Epithelial Dysplasia as Visualized by Noninvasive 3D Imaging

“…We anticipate that information gained from MPAM-SHGM could be used to develop improved diagnostic approaches either by other optical methods reliant on understanding of cellular/structural changes or even directly using MPAM-SHGM through endoscopy (47). The application of depth resolved optical imaging to human epithelial tissues (28, 48) including MPAM and SHGM (45, 46) and recent advancements that are pushing the depth limits of MPAM-SHGM and miniaturization (49) support the feasibility of MPAM-SHGM ECTI imaging in human tissue in the future.…”

“…This challenge may be lessened in other tissues, such as skin in which melanin in the dermis allows greater contrast between epithelium and lamina propria (27). This was shown in a study in which the dermal-epidermal junction was delineated in 3D from confocal reflectance microscopy (CRM) images of human skin (28). In that study, delineation was improved in dark skinned patients having more melanin in the dermis than fair skinned patients.…”

Validation study of automated dermal/epidermal junction localization algorithm in reflectance confocal microscopy images of skin

“…Additional challenges for automated-image analysis of RCM stacks from skin include heterogeneity of skin tissue, high inter- and intra-subject variability and low optical contrast. To overcome these challenges, we proposed a hybrid segmentation/classification algorithm for DE junction localization in lightly pigmented skin types 15–17 . This approach was a combination of two algorithms: First algorithm is the sequential image segmentation algorithm that partitioned the image sequences in depth (z) direction into homogenous groups using the dynamics of image features.…”

“…Recently, we extended this algorithm to locate the DE junction in dark skin 18 , in which strong backscatter from the melanin pigment causes the basal layer right above the DE junction to appear brright and with high contrast and was easier to detect compared to DE junction in fair skin stacks. In dark skin RCM stacks, the algorithm found the appropriate peak of the smoothed average intensity depth profile of an image region centered at position (x,y).…”

Automatic Quantification of Epidermis Curvature in H&E Stained Microscopic Skin Image of Mice

“…Several studies showed that the curvature of rete ridges can vary in ageing or obesity [9]. Other studies found several skin disorders are associated with changes in epidermal junction characterization, such as psoriasis [10]. The proposed method to quantify the curvature relies on measuring the difference between the actual border of the epidermis and a straight reference line connecting the two far sides of the border.…”