In vivo quantification of viscoelastic property alterations in oral submucous fibrosis using optical coherence elastography

Quantitative analysis of viscoelastic alterations in oral submucous fibrosis (OSF) provides crucial insights for monitoring disease progression and preventing malignant transformation. We developed a piezoelectric-based optical coherence elastography (OCE) system for real-time, <i>in vivo</i> quantitative assessment of OSF progression. In our experimental model, sixteen rats were systematically divided into four groups representing progressive fibrosis stages. Phase-sensitive OCE measurements captured distinctive elastic wave propagation patterns across all experimental groups. Comprehensive analysis of phase velocity dispersion curves and wave attenuation enabled the extraction of quantitative viscoelastic parameters that reflect fundamental tissue changes. Results demonstrated significant biomechanical alterations with disease progression, most notably a nearly four-fold increase in Young's modulus from normal tissue (32.6 ± 3.9 kPa) to severe fibrosis (121.1 ± 9.9 kPa), accompanied by more than doubled viscosity coefficients (0.52 ± 0.06 Pa·s to 1.27 ± 0.15 Pa·s). Particularly significant was the loss factor (G"/G') pattern, which exhibited a non-monotonic trend-decreasing from 0.30 in control specimens to 0.18 in moderate fibrosis groups before slightly increasing to 0.20 in severe fibrosis groups. The viscoelastic parameters quantified by OCE may facilitate more precise staging of OSF and potentially provide early indicators for assessing progression risk toward malignancy.