Clinical and morphological determinants of minimally-invasive electrical impedance spectroscopy measurements in pulmonary nodules: an exploratory correlation pilot study

Accurate diagnosis of peripheral pulmonary nodules remains challenging. Electrical impedance spectroscopy (EIS) may provide a radiation-free approach for pre-biopsy tissue characterization during bronchoscopy. This study investigated the relationship between bioimpedance-derived parameters, radiological and clinical characteristics of malignant peripheral pulmonary nodules. Fifteen patients undergoing electromagnetic navigation bronchoscopy-guided biopsy of pulmonary nodules were included. EIS was performed on healthy lung tissue and nodules. Resistance and reactance were analysed against lesion volume, major and minor diameters, maximum standardized uptake value, and biopsy-derived tissue volume. Associations were assessed using Spearman correlation, and ROC analysis evaluated discrimination between healthy and nodular tissue. Bioimpedance significantly differentiated malignant nodular tissue from healthy lung tissue ( P < 0.01). Major nodule diameter showed the largest unadjusted correlations with resistance (ρ = −0.52, P = 0.046) and a trend toward reactance (ρ = 0.46, P = 0.08), although neither remained significant after false discovery rate correction. ROC analysis demonstrated good discriminatory performance, with area under the curve values exceeding 0.80 across most diameter-based subgroups. EIS-derived bioimpedance parameters distinguished malignant nodular tissue from healthy lung tissue and showed exploratory associations with gross lesion dimensions. These findings support EIS as a promising complementary tool for bronchoscopy lesion characterization.