The Application of High-Frequency Ultrasonography in Post-Therapeutic Assessment of Actinic Keratosis After Photodynamic Therapy.

OBJECTIVES

Actinic keratoses (AKs) are one of the most common reasons for consultation in the elderly population. This study aimed to assess the efficacy of 5-ALA PDT in AK treatment using high-frequency ultrasonography (HFUS) to evaluate skin layer changes during therapy.

METHODS

In our study, we included 44 AK patients aged 53 to 89 years. All patients had lesions clinically evaluated with the Olsen and AKASI scale. HFUS imaging was performed on seemingly healthy skin and lesions before and at 4, 8, and 12 weeks of therapy. Ultrasound markers such as skin thickness, echogenicity, and pixel intensity were measured. 5-ALA was applied under occlusion for 3 h. After removing the occlusive dressing, 5-ALA was removed with a saline solution and a directed therapy with a BF-200 lamp. Full follow-ups of 56 markers of suitable quality were selected.

RESULTS

The thickness of SLEB significantly decreased in the following weeks compared to the pre-therapy results, reaching its lowest values after 12 weeks. The average pixel intensity significantly increased in each skin layer after therapy (p < 0.01). For SLEB, there were statistically significant differences in LEP, MEP and contrast. The AKASI score before and after treatment was determined for the 39 patients who underwent follow-up at week 12. The median AKASI score was 3.2 (1.2-8.6) before treatment and 0.6 (0-2.8) after.

CONCLUSIONS

According to the literature data, this is the first study describing the ALA-PDT treatment efficacy in different AK severities evaluated in HFUS. HFUS provides a valuable non-invasive tool for monitoring the efficacy of PDT in AK treatment, showing significant improvements in skin texture and structure.