Individualized HIFU in women over 60: ultrasound assessment of layer-specific facial soft-tissue thickness changes.

High-intensity focused ultrasound (HIFU) is widely used for facial rejuvenation, but standardized depth settings may not adequately account for age-related variation in facial soft tissue architecture in women aged 60 years and older. In this exploratory pilot study, 20 women underwent three HIFU sessions at 4-week intervals (Weeks 0, 4, and 8) and were evaluated at Week 16 (8 weeks after the final session). Participants received either a conventional protocol or an anatomy-guided protocol individualized using high-frequency ultrasound (HFUS) measurements. HFUS assessed superficial fat thickness, deep fat thickness, and skin-to-SMAS distance at baseline and Week 16. Both protocols produced reductions in lower-face and submental tissue thicknesses. Across all HFUS endpoints, the anatomy-guided protocol showed larger mean reductions than the conventional protocol. In this exploratory analysis, nominal, unadjusted between-group differences were observed for lower-face skin-to-SMAS distance (difference in change, - 0.19 mm; 95% CI, - 0.38 to - 0.02; p = 0.035), submental superficial fat thickness (- 0.20 mm; 95% CI, - 0.39 to - 0.02; p = 0.032), and submental skin-to-SMAS distance (- 0.19 mm; 95% CI, - 0.38 to - 0.02; p = 0.035). These differences were small in absolute magnitude and should be interpreted cautiously in relation to ultrasound measurement precision. Investigator-rated improvement of "much improved" or better occurred in 40% of the conventional group and 60% of the anatomy-guided group. These preliminary findings suggest that anatomy-informed HIFU may be associated with small, layer-specific ultrasound-measured soft-tissue thickness changes in older women; however, the submillimeter magnitude of the differences, small sample size, parallel-group design, and short follow-up warrant cautious interpretation.