Can Multispectral Imaging Revolutionize Skin Disease Assessment?

🔍 Key Finding Recent studies show portable and cost-efficient multispectral imaging (MSI) systems can extract skin lesion characteristics useful for early melanoma diagnosis, potentially improving diagnostic specificity compared to classic dermoscopy, though further development is needed for a fully-fledged diagnostic MSI device.

🔬 Methodology Overview

• Design: Narrative review.
• Data Sources: PubMed, Web of Sciences, IEEE Xplore, Science Direct, Springer, SPIE, and Wiley databases.
• Selection Criteria: Papers published between 2012-2022 focusing on multispectral imaging (MSI) systems for skin lesion evaluation, particularly for dermatological applications. Keyword filters included “multispectral imaging,” “dermatology,” “skin cancer detection,” and “skin lesion assessment.” Further refinement to 17 papers (4 commercial systems, 13 prototypes).
• Analysis Approach: Qualitative synthesis of hardware characteristics, performance metrics (sensitivity, specificity), advantages, and limitations of selected MSI systems. Comparative analysis of commercial systems and prototypes.
• Scope: Overview of MSI technology for skin disease assessment, focusing on the evolution of MSI systems over the past decade and their potential for future development and clinical integration.

📊 Results

• Commercial MSI Systems: MelaFind showed 70-100% sensitivity but only 9.8-82.5% specificity for melanoma detection. MoleMate (SIAscope) achieved 81-100% sensitivity and 59-91% specificity. DermoSight achieved 97-99% sensitivity and specificity in a study of 712 skin lesions.
• MSI Prototype Performance: A prototype by Delpueyo et al. reached 91.3% sensitivity and 54.5% specificity for melanoma and basal cell carcinoma detection. Another prototype by Rey-Barroso et al. achieved 78.6% sensitivity and 84.6% specificity using extended NIR wavelengths. Lihacova et al.’s prototype, combining multispectral imaging and autofluorescence, demonstrated 75% sensitivity and 100% specificity for melanoma vs. dysplastic nevi.
• Spectral Bands and Chromophores: Studies used 3 to 30 spectral bands, typically selecting wavelengths corresponding to peak absorbance of melanin (around 660 nm), blood (around 525 nm), and deeper tissue penetration (around 950 nm and above).
• Depth Penetration: MSI systems can achieve penetration depths up to 2.5 mm, enabling visualization of subsurface structures inaccessible to dermoscopy. One study showed melanoma lesions remained visible in images at 950 nm while benign nevi vanished after 850 nm, suggesting potential for depth estimation.
• Polarization: Several prototypes incorporated polarized light to reduce surface reflection and enhance image contrast, showing promising results for differentiating melanoma from benign nevi.
• Smartphone Integration: Prototypes demonstrated the feasibility of smartphone-based MSI systems, offering potential for portable and low-cost skin lesion assessment.
• Limitations: Many prototype studies had small datasets, requiring further clinical validation. Low specificity remains a challenge for widespread clinical adoption of MSI for standalone screening.

💡 Clinical Impact This review highlights the potential of multispectral imaging (MSI) as a cost-effective tool for improving the specificity of skin cancer diagnoses, particularly differentiating melanoma from benign nevi, which could reduce unnecessary biopsies and enhance early detection. While not yet a standalone diagnostic tool, MSI systems show promise as adjuncts to current dermatological practice, potentially streamlining the diagnostic process and improving patient outcomes.

🤔 Limitations

• Limited depth penetration of some techniques, such as dermoscopy and confocal microscopy.
• Low specificity of current commercially available MSI systems, leading to high false-positive rates.
• Dependence on the experience of the professional for accurate dermoscopic diagnosis.
• High cost of equipment for techniques like confocal microscopy and multiphoton topography.
• Limited resolution of OCT, affecting its ability to visualize cellular-level details.
• Motion artifacts affecting image quality in techniques like multiphoton topography and 3D topography.
• Lack of extensive clinical validation for many prototype MSI systems.

✨ What It Means For You This research reviews the development of multispectral imaging (MSI) systems for skin lesion assessment, highlighting their potential to improve diagnostic accuracy, particularly for melanoma, through non-invasive chromophore mapping and subsurface tissue visualization. While current MSI systems show promise as adjunctive tools, further development is needed to enhance specificity and establish them as standalone diagnostic devices, potentially streamlining the diagnostic process and reducing unnecessary biopsies.

Reference Ilisanu M-A, Moldoveanu F, Moldoveanu A. Multispectral Imaging for Skin Diseases Assessment—State of the Art and Perspectives. Sensors. 2023;23:3888. https://doi.org/10.3390/s23083888