Noninvasive Electrical Conductivity Mapping by MRI: Its Diagnostic Potential in Distinguishing Thoracic Lesions

Electric properties tomography (EPT) enables noninvasive quantification of tissue electrical conductivity (σ), offering potential biomarkers for tissue characterization. However, the technical feasibility and diagnostic utility of phase-based EPT in thoracic applications remain limited. This study presents a comprehensive evaluation of phase-based EPT for thoracic lesion characterization. Twenty patients with focal lung or mediastinal lesions underwent 1.5T MRI including sagittal two-dimensional steady-state free precession imaging for EPT reconstruction and diffusion-weighted imaging for comparison. σ maps were successfully reconstructed using phase-based methods, with histogram and texture analysis performed to extract quantitative features. Following multicollinearity assessment using variance inflation factor analysis, five independent predictors were identified: three σ-derived features (entropy, kurtosis, and joint energy) and two apparent diffusion coefficient (ADC)-derived features (10th percentile and contrast). The σ-based and ADC-based diagnostic indices achieved comparable performance with area under the curve (AUC) values of 0.869 (95% confidence interval [CI]: 0.650-1) and 0.893 (95% CI: 0.742-1), respectively. Two-dimensional clustering analysis revealed that adenocarcinoma demonstrated significantly higher complexity in the combined σ-ADC parameter space [cluster number: 10.5 (6.8-13.3)] compared with squamous cell carcinoma [4.5 (4.0-5.8); p = 0.003] and benign lesions [6.5 (6.0-7.0); p = 0.014]. These findings demonstrate that σ measurements provide complementary information to ADC for lesion characterization. Importantly, σ measurements showed robustness to lesion anatomical location, indicating the technical reliability of the phase-based EPT approach in thoracic imaging.