Advancements in Noninvasive Imaging: Optical Coherence Tomography for Evaluating Therapeutic Efficacy in Vitiligo

Pigmentary disorders, particularly vitiligo, present significant challenges in dermatological treatment. Accurate monitoring of therapeutic efficacy is essential for optimizing treatment strategies. Noninvasive imaging offers a promising solution for real-time evaluation of skin changes, enabling clinicians to assess treatment outcomes while limiting invasive procedures. This manuscript analyzes the application of noninvasive imaging modalities, specifically optical coherence tomography (OCT), in assessing therapeutic responses in patients with vitiligo.

OCT integrates ultrasonography and optical interferometry to image skin horizontally and vertically up to 1–2 mm deep, capable of generating 3D images, particularly beneficial for deeper basal cell carcinoma subtypes and monitoring treatment responses while limiting additional biopsies, such as verifying clear margins and assessing therapeutic efficacy at the cellular level [1, 2]. OCT is emerging as a practical, noninvasive tool for evaluating skin characteristics and tracking surgical treatment responses in patients with pigmentary disorders, such as vitiligo. Vitiligo is characterized by autoimmune-mediated loss of melanocytes and impaired melanin synthesis. OCT imaging can visualize skin changes by revealing decreased or absent scattering contrast between the stratum basale and dermal papillae. Recent studies demonstrate OCT's efficacy in assessing repigmentation post-skin grafting, detecting signs as early as Day 30 [1].

In comparison, techniques such as reflectance confocal microscopy (RCM) quantify vitiligo treatment response at a cellular level, capturing melanocyte migration across submillimeter scales [3]. RCM visualizes cellular features in the epidermis, dermal–epidermal junction, and papillary dermis at near-histological resolution, using differential refractive indices to capture grayscale images up to 300 μm deep horizontally. This allows for enhanced diagnostic accuracy for melanocytic and non-melanocytic skin cancers, aiding in the diagnosis of inflammatory and infectious skin disorders [3]. The VivaScope 1500 RCM device, with its high lateral resolution (~1 μm), limited imaging depth (~200–250 μm), and mosaic field of view (~8 × 8 mm), excels in detailed visualization of epidermal and dermo-epidermal structures, such as melanocytes and keratinocytes, making it particularly effective for assessing cellular-level repigmentation in vitiligo [4]. In contrast, ultrahigh-resolution OCT, with a lower lateral resolution (~5–15 μm) but greater imaging depth (~1–2 mm) and comparable field of view (~8 × 8 mm), is better suited for efficiently monitoring structural changes in dermal papillae and larger-scale tissue alterations post-treatment (Table 1) [1, 4].

Case studies using OCT for real-time monitoring of epidermal and dermal changes in vitiligo show promising results. One study investigated high-resolution full-field optical coherence tomography (CRFF-OCT) for assessing vitiligo lesions post-tissue grafting in 10 patients [2]. Over 6 months, clinical, dermoscopic, and photographic data revealed melanin loss as a distinct dark band in vitiligo lesions using CRFF-OCT. Grafted areas exhibited melanocytes with dendrites around the epidermal–dermal junction and hair follicles. CRFF-OCT effectively detected early melanocyte recovery and accurately quantified melanin [2]. OCT detected early melanin recovery, which validated treatment efficacy and guided clinical decisions by precisely assessing pigmentary changes, showing promise in enhancing diagnostic accuracy and optimizing therapeutic regimens in vitiligo [2].

Other promising noninvasive imaging tools for post-treatment vitiligo monitoring include fluorescence-advanced videodermoscopy (FAV) for visualizing pigmented cell proliferation at the dermal–epidermal junction and high-frequency ultrasound (HFUS) for detecting subclinical inflammatory patterns [5, 6].

Noninvasive imaging techniques, particularly OCT, are of growing importance in the management of pigmentary disorders such as vitiligo by enabling precise and quantifiable monitoring of treatment responses. Future research, particularly on combining OCT with multispectral imaging or confocal microscopy may offer deeper insights into skin pigmentation changes and treatment outcomes (Table 2). Enhancing imaging resolution and depth through artificial intelligence and machine learning, as well as exploring OCT's role in targeted drug delivery, holds potential for advancing dermatological care. Continued research is essential to optimize OCT and integrate it effectively with complementary tools.

The authors have nothing to report.

The authors declare no conflicts of interest.