3D photography is a reliable method of measuring infantile haemangioma volume over time

Photography and Image Acquisition in Dermatology a Scoping Review: Techniques for High-Quality Photography

BACKGROUND

Clinical photography is essential in dermatology, in particular in the areas of surgical and cosmetic dermatology and has been evolving rapidly. However, many dermatologists desire more training in clinical photography and a comprehensive literature review of photography in dermatology is lacking.

OBJECTIVE

This scoping review aimed to summarize the literature regarding techniques for high-quality photography in dermatology.

MATERIALS AND METHODS

A literature search was conducted using Embase, MEDLINE, PubMed, and Evidence-Based Medicine databases in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews.

RESULTS

This review summarizes information from 74 studies. Camera type, resolution, lens choice, camera settings, environment and set-up, standardization, and types of clinical photography are all important factors in acquisition of high-quality photography.

CONCLUSION

Photography in dermatology is continuously evolving with broader applications. Improved practices and innovations will benefit the quality of images.

Conventional and three-dimensional photography as a tool to map distribution patterns of in-transit melanoma metastases on the lower extremity

Background

In melanoma, in-transit metastases characteristically occur at the lower extremity along lymphatic vessels.

Objectives

The objective of this study was to evaluate conventional or three-dimensional photography as a tool to analyze in-transit metastasis pattern of melanoma of the lower extremity. In addition, we assessed risk factors for the development of in-transit metastases in cutaneous melanoma.

Methods

In this retrospective, monocentric study first we compared the clinical data of all evaluable patients with in-transit metastases of melanoma on the lower extremity (n = 94) with melanoma patients without recurrence of disease (n = 288). In addition, based on conventional (n = 24) and three-dimensional photography (n = 22), we defined the specific distribution patterns of the in-transit metastases on the lower extremity.

Results

Using a multivariate analysis we identified nodular melanoma, tumor thickness, and ulceration as independent risk factors to develop in-transit metastases ITM (n = 94). In patients with melanoma on the lower leg (n = 31), in-transit metastases preferentially developed along anatomically predefined lymphatic pathways. In contrast when analyzing in-transit metastases of melanoma on the foot (n = 15) no clear pattern could be visualized. In addition, no difference in distance between in-transit metastases and primary melanoma on the foot compared to the lower leg was observed using three-dimensional photography (n = 22).

Conclusion

A risk-adapted follow-up of melanoma patients to detect in-transit metastases can be applied by knowledge of the specific lymphatic drainage of the lower extremity. Our current analysis suggests a more complex lymphatic drainage of the foot.

Colorimetric analysis of images in the follow-up of infantile hemangiomas

BACKGROUND/OBJECTIVES

Infantile hemangiomas (IH) are common vascular tumors that appear early in life, have a rapid proliferative phase and slowly involute. There are no standardized ways to evaluate the regression of these lesions. We propose a colorimetric analysis of photographs to allow a more precise determination of IH treatment response and involution.

METHODS

Patients 1-10 months of age with superficial or mixed IH were included. The lesions were managed with 0.5% topical timolol ophthalmic solution. Patients were followed for 16 weeks with 6 evaluations each. Photographic images were taken with a red and green circle placed beside each hemangioma. The photographs were treated as to equalize the size, color, and brightness among them based on the colors of the two circles. A grading scale was established based on the color of the patient skin (0) and the color of the hemangioma at the beginning of treatment (100) by pixel analysis using Adobe Photoshop® software.

RESULTS

A total of 17 patients 1 to 10 months of age were included, of whom 16 were girls (94%). Fourteen lesions were superficial, and 3 were mixed IH. The median time prior to initiation of treatment was 105 days (44-232). All lesions showed some degree of clearing. The mean of lightening of color intensity observed was of 45% (17%-74%) over the period of follow-up.

CONCLUSIONS

The colorimetric analysis of the digital images allowed an accurate and objective evaluation of IH clearing.

Incorporation of 3D stereophotogrammetry as a reliable method for assessing scar volume in standard clinical practice

Significant disfigurement and dysfunction is caused by hypertrophic scarring, a prevalent complication of burn wounds. A lack of objective tools in the assessment of scar parameters makes evaluation of scar treatment modalities difficult. 3D stereophotogrammetry, obtaining measurements from 3D photographs, represents a method to quantitate scar volume, and a 3D camera may have use in clinical practice. To validate this method, scar models were created and photographed with a 3D camera. Measurements from 3D image analysis of these scar models were compared to physical measurements of scar model volume. Reliability of 3D image analysis was assessed with both scar models and burn patient scars. Measurements of scar models by two independent observers were compared to determine inter-rater reliability, and measurements from 3D images of burn patient hypertrophic scars were compared to determine the consistency of the method between observers. The time taken for patient photography was recorded. No significant differences were found between the two methods of volume calculation (p = 0.89), and a plot of the differences showed agreement between the methods. The correlation coefficient between the two observers' measurements of scar model volume was 0.92, and the intra-class correlation coefficient for patient scar volume was 0.998, showing good reliability. The time required to capture 3D photographs ranged from 2 to 6 min per patient, showing the potential for this tool to be efficiently incorporated into clinical practice. 3D stereophotogrammetry is a valid method to reliably measure scar volume and may be used to objectively measure efficacy of scar treatment modalities to track scar development and resolution.

Stereophotogrammetric three-dimensional photography is an accurate and precise planimetric method for the clinical visualization and quantification of human papilloma virus-induced skin lesions

Background

The quantification of human papilloma virus (HPV)‐induced skin lesions is essential for the clinical assessment of the course of disease and the response to treatment. However, clinical assessments that measure dimensions of lesions using a caliper do not provide complete insight into three‐dimensional (3D) lesions, and its inter‐rater variability is often poor.

Objective

The aim of this study was to validate a stereophotogrammetric 3D camera system for the quantification of HPV‐induced lesions.

Methods

The camera system was validated for accuracy, precision and interoperator and inter‐rater variability. Subsequently, 3D photographs were quantified and compared to caliper measurements for clinical validation by Bland–Altman modelling, based on data from 80 patients with cutaneous warts (CW), 24 with anogenital warts (AGW) patients and 12 with high‐grade squamous intraepithelial lesions of the vulva (vulvar HSIL) with a total lesion count of 220 CW, 74 AGW and 31 vulvar HSIL.

Results

Technical validation showed excellent accuracy [coefficients of variation (CV) ≤ 0.68%] and reproducibility (CVs ≤ 2%), a good to excellent agreement between operators (CVs ≤ 8.7%) and a good to excellent agreement between different raters for all three lesion types (ICCs ≥ 0.86). When comparing 3D with caliper measurements, excellent biases were found for diameter of AGW (long diameter 5%), good biases were found for diameter of AGW (short diameter 10%) and height of CW (8%), and acceptable biases were found for the diameter of CW (11%) and vulvar HSIL (short diameter 14%, long diameter 16%). An unfavourable difference between these methods (bias 25%) was found for the assessment of height of AGWs.

Conclusion

Stereophotogrammetric 3D imaging is an accurate and reliable method for the clinical visualization and quantification of HPV‐induced skin lesions.

Linked Commentary: M. Skerlev et al. J Eur Acad Dermatol Venereol 2019; 33: 1445–1446. https://doi.org/10.1111/jdv.15791.

Finite Element Model and Validation of Nasal Tip Deformation

Nasal tip mechanical stability is important for functional and cosmetic nasal airway surgery. Palpation of the nasal tip provides information on tip strength to the surgeon, though it is a purely subjective assessment. Providing a means to simulate nasal tip deformation with a validated model can offer a more objective approach in understanding the mechanics and nuances of the nasal tip support and eventual nasal mechanics as a whole. Herein we present validation of a finite element (FE) model of the nose using physical measurements recorded using an ABS plastic-silicone nasal phantom. Three-dimensional photogrammetry was used to capture the geometry of the phantom at rest and while under steady state load. The silicone used to make the phantom was mechanically tested and characterized using a linear elastic constitutive model. Surface point clouds of the silicone and FE model were compared for both the loaded and unloaded state. The average Hausdorff distance between actual measurements and FE simulations across the nose were 0.39 ± 1.04 mm and deviated up to 2 mm at the outermost boundaries of the model. FE simulation and measurements were in near complete agreement in the immediate vicinity of the nasal tip with millimeter accuracy. We have demonstrated validation of a two-component nasal FE model, which could be used to model more complex modes of deformation where direct measurement may be challenging. This is the first step in developing a nasal model to simulate nasal mechanics and ultimately the interaction between geometry and airflow.