Tivita parameters in HIs and patients, and correlation with GlycoCheck parameters and EASIX. (A) Overview of the Tivita HSI system, including measurement positions (left palm and left fourth fingertip) and representative spectral images showing: (top) Tissue oxygen saturation; (middle) NIR; (bottom) TWI. (B) Box plots comparing age-matched HIs and patients for Tivita parameters (NIR and TWI, n = 100). Wilcoxon rank-sum tests were used to assess significance (P values shown). No significant differences were found between younger and older HI subgroups, whereas patients significantly differed from older HI subgroups (NIR, TWI) and younger HI subgroups (TWI). (C) Correlation analyses between GlycoCheck parameters and Tivita measures. (Left) Correlation between vascular density and NIR; (right) correlation between PBR and TWI. Spearman ρ correlation coefficients (red line) with 95% CIs (gray and black lines) are shown by VD (4-25 μm). A correlation was considered significant if the entire CI lay on 1 side of the y-axis. (D) Linear regression analysis between EASIX and Tivita parameters. (Left) Negative correlation between EASIX and NIR (reduced perfusion); (right) positive correlation between EASIX and TWI (increased vascular permeability).