Inter-Device Agreement Between Vectra H2 and LifeViz Mini for Nasolabial Volumetric Assessment After Thread Lifting: A Post Hoc Method-Comparison Study

Abstract Background Objective quantification of subtle facial volume change requires reliable three-dimensional (3D) imaging, but measurements from different systems may not be equivalent. Objectives To evaluate agreement between Vectra H2 and LifeViz Mini for nasolabial volumetric assessment after thread lifting. Methods This post hoc secondary retrospective method-comparison study analyzed paired images prospectively acquired in a parent study. Fifteen women treated with absorbable polydioxanone mesh threads contributed 74 paired side-specific measurements across 43 participant visits. A standardized 1 cm2 nasolabial region of interest was analyzed with Vectra H2 (Canfield Scientific, Inc., Parsippany, NJ) and LifeViz Mini (QuantifiCare S.A., Valbonne, France). Agreement was assessed using an absolute-agreement intraclass correlation coefficient (ICC), Bland-Altman analysis, and paired testing. A participant-level sensitivity analysis averaged bilateral measurements within visits and then averaged visits within each participant. Results Mean age was 41.87 ± 7.85 years (range, 34-56 years). The paired measurements did not differ significantly (exact two-sided Wilcoxon P=.356); the median LifeViz Mini-minus-Vectra H2 difference was 0.00108 cm3. The ICC was 0.977 (95% CI, 0.963-0.985). Mean bias was 0.00045 cm3, with limits of agreement from -0.00924 to 0.01013 cm3. Participant-level findings were consistent (P=.804; ICC=0.953; mean bias, 0.00019 cm3). Conclusions Vectra H2 and LifeViz Mini produced highly concordant nasolabial volume-change measurements under standardized conditions. The participant-level sensitivity analysis supported the robustness of the findings, although larger prospective studies are required.