High-frequency ultrasound in anti-aging skin therapy monitoring

Abstract

Over the last few decades, high-frequency ultrasound has found multiple applications in various diagnostic fields. The fast development of this imaging technique opens up new diagnostic paths in dermatology, allergology, cosmetology, and aesthetic medicine. In this paper, being the first in this area, we discuss the usability of HFUS in anti-aging skin therapy assessment. The fully automated algorithm combining high-quality image selection and entry echo layer segmentation steps followed by the dermal parameters estimation enables qualitative and quantitative evaluation of the effectiveness of anti-aging products. Considering the parameters of subcutaneous layers, the proposed framework provides a reliable tool for TCA-peel therapy assessment; however, it can be successfully applied to other skin-condition-related problems. In this randomized controlled clinical trial, forty-six postmenopausal women were randomly assigned to the experimental and control groups. Women were treated four times at one-week intervals and applied skin cream daily between visits. The three month follow-up study enables measurement of the long-term effect of the therapy. According to the results, the TCA-based therapy increased epidermal (entry echo layer) thickness, indicating that the thinning process has slowed down and the skin’s condition has improved. An interesting outcome is the obtained growth in the intensity of the upper dermis in the experimental group, which might suggest a reduced photo-aging effect of TCA-peel and increased water content. The same conclusions connected with the anti-aging effect of TCA-peel can be drawn by observing the parameters describing the contribution of low and medium-intensity pixels in the upper dermis. The decreased share of low-intensity pixels and increased share of medium-intensity pixels in the upper dermis suggest a significant increase in local protein synthesis.

Dermatological ultrasound in assessing skin aging

“…Its functionality is grounded in the distinct reflection patterns within various tissues, delineating differences in keratin, collagen, and water content. In dermatological applications, the necessity to visualize superficial structures demands higher frequencies ( 9 ). This increased frequency directly correlates with improved resolution, enabling finer details to be captured and enhancing the precision of dermatological imaging ( 10 ).…”

“…Transducers are categorized into high (>15 MHz), very high (>20 MHz), and ultrahigh-frequency (30–70 MHz). These devices penetrate between 8 and 30 mm, enabling evaluation of the dermis and subcutaneous layers, or even the epidermis if ultrahigh frequency exceeds 50 MHz ( 9 ). The preferred method in Dermatology is B-mode scanning, which converts reflected waves into corresponding ‘brightness’ values displayed on a gray scale ( 10 ).…”

“…Notably, sun-exposed area thickness tends to increase after age 60, while photo-protected areas do not exhibit significant age-related changes ( 28 ). Studies utilizing US analyses have demonstrated increased epidermal thickness following the use of retinaldehyde ( 29 ), vitamin C ( 30 ), and TCA peeling ( 9 ). Another study involving ablative CO2 laser treatment for improving photoaging revealed varying outcomes in different areas of the same patient’s face when using identical parameters.…”

“…The evaluation of echogenicity holds significant importance. Echogenicity typically demonstrates an augmentation associated with aging, in correlation with heightened collagen production and lower amount of intercellular substance ( 9 ). Variations in skin echogenicity have been extensively documented in anti-aging treatments, revealing increased echogenicity in both the epidermis and dermis ( 27 ).…”

“…Echogenicity can be objectively assessed by the quantity and mean intensity of pixels ( 27 , 33 ). Thus, it can be classified into three categories: Low Echogenic Pixels (LEP) ranging from 0 to 30, Medium Echogenic Pixels (MEP) within the 50–150 interval, and High Echogenic Pixels (HEP) between 200 and 255 ( 9 ). It becomes feasible to measure the quantity of pixels attributed to LEP, MEP, and HEP.…”