Real-time Analysis of Skin Biopsy Specimens With 2-Photon Fluorescence Microscopy

Importance

Nonmelanoma skin cancers (NMSCs) are primarily diagnosed through paraffin section histologic analysis of skin biopsy specimens that requires days to weeks before a formal diagnosis is reported. Two-photon fluorescence microscopy (TPFM) has the potential for point-of-care diagnosis of NMSC and other dermatologic conditions, which could enable same-visit diagnosis and treatment.

Objective

To demonstrate that TPFM imaging of NMSC can occur within minutes of obtaining biopsies and provide similar histological features to those of conventional histology and evaluate TPFM diagnostic performance with respect to conventional histology.

Design, Setting, and Participants

This comparative effectiveness pilot study examined 29 freshly excised biopsies from confirmed NMSC lesions in patients presenting for treatment. Biopsies underwent imaging immediately with TPFM on site at Rochester Dermatologic Surgery (Victor, New York) between October 2019 and August 2021. The imaged biopsies were subsequently submitted for paraffin histology to produce coregistered images. Twelve of these coregistered image pairs (41.4%) were used as a training set. Fifteen (51.7%) were used in a masked evaluation by a board-certified dermatopathologist. Two (6.9%) were excluded from the study before evaluation because they could not be coregistered.

Main Outcomes and Measures

Sensitivity, specificity, and accuracy of TPFM for NMSC biopsies were evaluated compared with conventional histology.

Results

Fourteen of the 15 biopsy specimens (93.3%) in the evaluation set were identically diagnosed with TPFM and paraffin histology. The TPFM had 100% sensitivity (95% CI, 48%-100%), 100% specificity (95% CI, 69%-100%), and 100% accuracy (95% CI, 78%-100%) for basal cell carcinoma diagnosis. For squamous cell carcinoma diagnosis, TPFM had 89% sensitivity (95% CI, 52%-100), 100% specificity (95% CI, 54%-100%), and 93% accuracy (95% CI, 68%-100%). For overall NMSC diagnosis, TPFM had a 93% sensitivity (95% CI, 66%-100%), 100% specificity (95% CI, 3%-100%), and 93% accuracy (95% CI, 68%-100%). Examination of the 1 discordant pair revealed mismatched imaging planes as the source of error.

Conclusions and Relevance

The results of this comparative effectiveness pilot study suggest that TPFM captures histological characteristics of NMSC that are present in conventional histology, which reveals its potential as a rapid, point-of-care diagnostic alternative that does not need extensive sample preparation or retraining for image evaluation. Further validation of TPFM imaging performed for a larger cohort is needed to fully evaluate its diagnostic accuracy and potential effect within the field.

Noninvasive and real-time in vivo characterization of Inflammation skin. A feasibility of animal study

BACKGROUND

Inflammatory skin diseases were the most common problem in dermatology. This study aimed to develop a circuit by using a simple method for noninvasive, objective, and real-time skin inflammation screening.

MATERIALS AND METHODS

Sprague-Dawley rats were used in this study. The rats were chemically induced to suffer from skin inflammation at the back of their left-hand side while the right-hand side of their back remained untreated serving as a control. Impedance (Z) spectrum of the rat's skin was recorded.

RESULTS

Two characteristic frequencies (4.5 and 48.3 kHz) were found. At the two frequencies, the impedance of inflammatory skin tissue (Z_IST ) was found to be significantly (P < .05) smaller than that of normal healthy skin tissue (Z_NHST ). Moreover, the ratio of the impedance measured at 4.5 kHz (Z_f = 4 ._5 kHz ) to the impedance measured at 48.3 kHz (Z_{f = 48.3 kHz} ), that is, Z_{f = 4.5 kHz} /Z_{f = 48.3 kHz} , was capable of skin inflammation screening. It was observed that the inflammatory skin tissue (IST) had the smaller value of Z_f = 4 ._5 kHz /Z_{f = 48.3 kHz} (value < 8.5) and normal healthy skin tissue (NHST) had the higher value of Z_f = 4 ._5 kHz /Z_{f = 48.3 kHz} (value ≈ 10) which almost remained constant.

CONCLUSION

A circuit was developed which was used for measuring the skin impedance accurately at the two characteristic frequencies for skin inflammation screening.