Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2023;13(3):e2023189 1 Validating a Novel Technique of Dermatoscopic Imaging or Sequential Comparison of Target Lesions in Vitiligo Priyansh Gupta1, Anubha Dev1, Keshavamurthy Vinay1, Anuradha Bishnoi1, Muthu Sendhil Kumaran1, Davinder Parsad1 1 Department of Dermatology, Venereology and Leprology, Post Graduate Institute of Medical Education and Research, Chandigarh, India Key words: dermatoscopy, vitiligo, imaging, novel Citation: Gupta P, Dev A, Vinay K, Bishnoi A, Sendhil Kumaran M, Parsad D. Validating a Novel Technique of Dermatoscopic Imaging or Sequential Comparison of Target Lesions in Vitiligo. Dermatol Pract Concept. 2024;14(1):e2024003. DOI: https://doi.org/10.5826/ dpc.1401a3 Accepted: February 13, 2023; Published: January 2024 Copyright: ©2024 Gupta et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Keshavamurthy Vinay, Associate Professor, Department of Dermatology, Venereology and Leprology, Post Graduate Institute of Medical Education and Research, Chandigarh, India- 160012. Phone: +91-8872993222 Email: vinay.keshavmurthy@gmail.com Introduction Sequential dermatoscopy can be a handy tool to assess dis- ease activity in vitiligo and hence guide management prac- tices [1]. However, the small size of the contact plate of hand held dermatoscopes prevents the adequate capturing of im- ages of larger patches in entirety. “Wide area digital dermos- copy” (WADD) and Video-WADD, are certain modifications used to acquire images of lentigo maligna and congenital melanocytic nevus [2,3]. This study aimed at devising a new method to acquire and store dermatoscopic images of vitil- igo patches in entirety, which would facilitate easy sequential comparison. Case Presentation This prospective observational study was conducted at the outpatient department of a tertiary care center in India. Thirty patients of active vitiligo (defined as occurrence of new lesions or expansion of pre-existing lesions in the pre- vious 6 weeks) were recruited. Two target lesions were iden- tified in each patient and dermatoscopic assessment was performed at baseline and after 16 weeks of medical treat- ment resulting in 60 pairs of pre and post treatment photo- graphs. The detailed methodology of patient recruitment and follow-up has previously been published [4]. The reference points in the target lesion were marked according the markings on a clock, using different colored pens, akin to the technique used in Mohs micrographic sur- gery (Figure 1) [5]. Dermatoscopic images were acquired from each quadrant, while maintaining an overlap of 10% between images. Both lesional and perilesional skin were in- cluded as marginal lesions are crucial in determining disease activity and repigmentation. Images were then merged to ob- tain a consolidated image using Adobe Photoshop software (Adobe Inc., version CS3). 2 Research Letter | Dermatol Pract Concept. 2024;14(1):e2024003 The merged images were evaluated by 3 independent inves- tigators at the end of the study (VK, AB, and AD) and graded on a Likert scale (Table S1). Consensus was said to be reached for each image if two or more investigators scored equal grades. Additionally, each investigator also scored the pair of pre- and post-treatment consolidated image of each patient. Cohn Kappa analysis was performed for two observers and Fleiss Kappa assessment was done for more than two observers, with level of agreement more than 0.6 considered as significant. Amongst 120 consolidated images, consensus was not reached for one image, hence 119 images and 59 pairs were considered for analysis (Table 1). Level of agreement be- tween the three experts for consolidated mage analyses were acceptable (Cohn and Fleiss kappa value > 0.6). Conclusions The proposed technique has various advantages like ease of sequential comparison of dermatoscopic images post-treatment, more rapid assessment and reduced digital space usage in acquisition and storage of dermatoscopic images. Inter observer agreement was significant in majority Figure 1. (A) Pre-treatment merged dermoscopic image of a patch of vitiligo with no blurring/distortion or missing part (Grade 4) (red-colored mark denotes 12 o’clock mark or cephalic direction, blue-colored mark denotes 6 o’clock or caudal, green and black marks signify 9 and 3 o’clock or left and right respectively). (B) Merged dermatoscopic image of another patch of vitiligo with blurring but slight (<5%) distor- tion and missing part <5% limited to central area (Grade 3) (C) Merged dermatoscopic image of another patch of vitiligo with blurring and distortion more than 5% but less than 10% and missing part <10% limited to central area (Grade 2) (D) Merged dermatoscopic image of another patch of vitiligo with no distortion but blurring and missing more than 10% (Grade 1). Research Letter | Dermatol Pract Concept. 2024;14(1):e2024003 3 of instances overall, denoting the reliability and reproduc- ibility of this method in follow up of vitiligo. However, this method currently has its limitations as well like difficulty in merging images larger than 6 cm, deterio- ration of quality due to variation in the orientation of the dermatoscope with respect to the anatomical position of the body and unprecedented technological limitations, which warranted manual merging of certain images. References 1. Vinay, Ankad BS. Dermatoscopic features of pigmentary diseases in ethnic skin. Indian Dermatol Online J. 2021;12(1):24-33. DOI: 10.4103/idoj.IDOJ_561_20. PMID: 33768020; PMCID: PMC7982038. 2. Dellatorre G, Gadens GA. Wide area digital dermoscopy. J  Am Acad Dermatol. 2019;80(6):e153. DOI: 10.1016/j.jaad .2018.12.019. PMID: 30576760. 3. Dellatorre G, Gadens GA, Polo Silveira L, Kose K, Marghoob AA. Video-based wide area digital dermoscopy. J Am Acad Derma- tol. 2022;87(4):e125-e126. DOI: 10.1016/j.jaad.2021.06.842. PMID: 34146617. 4. Gupta P, Keshavamurthy V, Bishnoi A, Kumaran MS, Parsad D. A prospective observational study to sequentially determine the dermoscopic features of vitiligo and its association with disease activity in patients on medical treatment. Pigment Cell Melanoma Res. 2023;36(1):33-41. DOI: 10.1111/pcmr.13069. PMID: 36112075. 5. Xie Y, Bai J, Han L, Xia Y, Li L, Wan M. A novel way of map- ping in Mohs micrographic surgery. J Am Acad Dermatol. 2021;85(3):e145-e146. DOI: 10.1016/j.jaad.2019.03.019. PMID: 30885761. Table 1. Image quality analysis by three independent dermatoscopy experts (N = 120). Consolidated Image Analysis (N = 120)a Image Quality Expert 1 Expert 2 Expert 3 Consensus Fleiss kappa Grade 1 12 6 9 7 (5.9%) 0.679 Grade 2 12 11 9 11 (9.2%) Grade 3 19 20 19 17 (14.3%) Grade 4 77 83 83 84 (70.6%) Total 120 120 120 119 Paired image analysis (N = 60) Grade 1 11 6 7 7 (11.9%) 0.770 Grade 2 07 6 7 6 (10.1%) Grade 3 14 15 12 12 (20.3%) Grade 4 28 33 34 34 (57.6%) Total 60 60 60 59 aOne image in consolidated image analysis and one pair in paired image analysis excluded due to lack of consensus amongst three experts.