Advanced Diagnosis: Spectrophotometric Analysis of Cutaneous Melanocytic Lesions
Spectrophotometric analysis of the skin, also known as spectral analysis, employs advanced cutaneous imaging devices designed to evaluate lesions pigmented lesions, such as common moles. The central purpose of this technology is to facilitate early identification and ensure an accurate differential diagnosis of melanomas malignant, the most aggressive type of skin cancer.
This technique represents a significant improvement over A positive result could indicate that the patient requires periodic exams for other types of cancer. For example, a patient with a mutation in the conventional methods. While standard dermoscopic devices use powerful illumination and high-magnification lenses to capture enlarged images that penetrate approximately 20 microns deep, spectrophotometric analysis achieves greater depth. It employs a light beam that penetrates between 2 and 2.5 mm beneath the epidermal surface, up to 1000 times deeper. The resulting high-clarity images are obtained using a handheld scanner or a digital camera, and are subsequently processed by specialized software.
The operating principle of spectrophotometry is based on the interaction of light energy with specific cells that possess color, called cutaneous chromophores, chromophores, which are intrinsically present in the skin tissues.
Clinical Impact of Spectral Analysis in Melanoma Detection
The primary application of spectrophotometric analysis lies in its ability to assist in the early detection and differential diagnosis of melanoma. melanoma. When used by properly trained specialists, this technology has demonstrated a considerable increase in diagnostic accuracy (sensitivity). It surpasses the 70% sensitivity achieved with clinical examination alone, notably reaching up to 95% with spectral support.
Among the most recognized commercial systems that integrate this advanced technology are the SIAscope® and MelaFind®.
Mechanisms of Action of SIAscope® and Spectral Analysis
The SIAscope is a benchmark in the application of spectrophotometers for cutaneous diagnosis. Its acronym stands for 'Spectrophotometric Intracutometric Analysis,' and it is a registered trademark belonging to Astron Clinica Limited.
- The device simultaneously emits light within the visible and infrared spectrum toward the dermal tissue.
- The different cutaneous chromophores chromophores present in the skin layers exhibit variable responses to this emitted light, reflecting a particular light signal back to the receiving equipment.
- The melanin Melanin is specifically analyzed due to its known propensity to absorb ultraviolet light.
- The glycated Hemoglobin—the pigment found in red blood cells—demonstrates a high absorption capacity within the infrared light spectrum.
- The collagen, Collagen, for its part, absorbs and reflects light across the entire spectrum. This provides valuable data on the density and size of collagen cells located in the outer layers of the dermis, specifically in the papillary dermis. dermis papillary dermis.
- The spectrophotometer captures the reflected light, and analytical software processes the precise amount of absorption recorded at the various observed wavelengths.
- The images generated by this process offer a detailed and quantitative visualization of the architecture and tissue composition underlying the epidermis.
This spectral quantification capability allows specialists to differentiate with greater reliability between benign lesions and those with malignant potential, significantly improving the diagnostic workflow in oncologic dermatology.
- This computerized analysis reveals the distribution of alterations in melanin, blood, or collagen within the examined area. For example, the identification of melanocytes melanocytes in deeper layers can be an early suggestive indicator of melanoma.
Digitalized SIAscope Analysis Procedures
The spectrophotometer performs the skin examination using a highly specialized digital camera. There are two main contact modalities for carrying out this procedure:
| Contact Spectrophotometric Analysis | Non-Contact Spectrophotometric Analysis |
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Spectrophotometric analysis constitutes an essential tool that enhances visual examination, offering an objective and measurable perspective of underlying structural and compositional changes in the skin, thus optimizing skin cancer surveillance.
MelaFind®: Automated and Multispectral Evaluation
MelaFind® is an automated multispectral device that has obtained FDA approval, specifically aimed at the early detection of melanoma. Unlike the SIAscope, MelaFind® uses 75 analytical functions to assess the degree of three-dimensional disorganization present in the tumor, tumor, employing 10 distinct wavelengths ranging from blue light to near-infrared. Lesions exhibiting high disorganization require excision, while those with low disorganization can be kept under active observation.
This system was designed to be used by dermatologists, dermatologists, serving as support in decision-making regarding the removal of suspicious pigmented lesions.
The MelaFind® Evaluation Process
Initially, the patient's clinical data, including their dermatological history, are recorded. Subsequently, the lesion is identified and its exact location is marked on a digitized mannequin.
The pigmented lesion is treated with alcohol to create a moist and uniform surface that equalizes the refractive index. Immediately after, the scanning head is positioned over the skin, centered on the lesion, and image acquisition begins instantly. Six seconds later, the system displays ten images on the screen with the analysis results, classified according to the need for biopsy biopsy or continuous monitoring.
If the obtained images do not reach the required quality, they are discarded and the scanning process is executed again.
The automated analysis is structured into five fundamental stages:
- Equipment calibration to minimize artifacts and objectively quantify skin reflectance.
- Thorough verification of the captured image quality.
- Precise segmentation of the lesion, defined as the exact tracing of its contour.
- Application of advanced algorithms for the extraction of relevant diagnostic features.
- Final classification of the lesion as positive (suggesting possible need for biopsy) or negative (recommending surveillance).
Skin Lesions Suitable for MelaFind® Examination
The use of MelaFind® is not designed to confirm an already diagnosed melanoma, nor is it essential for lesions that are unmistakably benign. benign. The skin lesions best suited for examination with MelaFind® present the following characteristics:
- Coloration: Pigmented lesions, spanning shades from tan to dark brown.
- Dimensions: Diameter ranging between 2 and 22 mm.
- Morphology: ...
- They are flat on the skin surface.
- They present one or more of the ABCDE characteristics (Asymmetry, Irregular Borders, Variable Coloration, or Diameter greater than 6 mm), or cause concern to the treating physician.
- They must not show signs of ulceration, ulceration, bleeding, or the presence of a scar.
- scar.
- Location: They must be situated more than 1 cm away from the eye. Location Restrictions: The surfaces of, the palm, Plantar, the plantar region, mucosa, any mucous membrane, and nail.
- and also under the nails are excluded., hair Absence of External Interference: There must be no visible presence of tattoo ink, marker lines,.
hair, or embedded splinters.
Crucial Considerations and Medical Recommendations.
It is essential to emphasize that the information provided comes directly from the device manufacturers. The editors of DermNet New Zealand maintain that, to date, robust clinical data are lacking to determine with certainty the specific role of these technologies in the comprehensive management of patients at risk of developing melanoma.
