Quantitative classification of melasma with photoacoustic microscopy: a pilot study

Area of Science:

• Dermatology
• Medical Imaging
• Biophotonics

Background:

• Accurate melasma classification is crucial for effective treatment and diagnosis.
• Conventional methods like Wood's lamp and optical dermoscopy have limitations in quantitative preoperative assessment.

Purpose of the Study:

• To introduce photoacoustic microscopy (PAM) as a tool for quantitative melasma classification.
• To simultaneously assess melanin and vascular indicators for improved diagnostic accuracy.

Main Methods:

• Patients were initially classified using Wood's lamp and optical dermoscopy.
• In vivo examination was performed using a 3D photoacoustic microscopy (PAM) system.
• Horizontal section images of epidermal melanin and dermal vascularity were extracted for quantitative analysis.

Main Results:

• PAM quantitatively revealed epidermal thickness and dermal vascular morphology.
• Significant differences in vascular diameter and density were observed between lesional and non-lesional skin.
• Vascular parameters proved crucial for distinguishing between M and M+V melasma types.

Conclusions:

• PAM enables dual-standard quantitative melasma classification using melanin and vascular parameters.
• This technique provides new diagnostic insights for uncertain melasma cases.
• PAM refines melasma typing and enhances diagnostic capabilities.