Gastric Pain Early Detection by Conductivity-pH Dispersion (CpH-d) Score Based on 3D-Gastric Impedance Tomography

This study presents an innovative diagnostic approach for the early detection of gastric pain using the Conductivity-pH Dispersion (CpH-d) score derived from Three-Dimensional Gastric Impedance Tomography (3D-GIT). The CpH-d integrates gastric pH levels and conductivity distributions, visualized through reconstructed 3D tomographic images. These images were generated using a four-layered circular configuration of gel-based 32 AgCl electrodes, which function as non-contact pH sensors acquiring 928 tetrapolar impedance measurements every 40 s. Sixteen adults (20–40 y; healthy = 11, symptomatic = 5) completed a four-phase protocol (fasting, post-water storage, serial emptying, post-meal refill), after which CpH-d—the covariance-normalized joint dispersion of mean conductivity and pH—was summarized per subject; healthy stomachs showed large conductivity swings and broad pH excursions (4.5–6.8), whereas symptomatic stomachs exhibited blunted variability (5.1–5.4). A logistic classifier trained on CpH-d achieved 81.3 % accuracy, 91 % specificity, and 60 % sensitivity at an optimal probability cut-off of 0.61 (AUC = 0.87), outperforming a Bayes Gaussian-intersection rule that reached only 69 % accuracy. By capturing coupled electro-chemical gastric dynamics without radiation, catheterization, or endoscopy, CpH-d and the 3D-GIT platform offer a promising route toward point-of-care monitoring of dyspepsia and related disorders, with future work targeting larger cohorts and real-time viscosity/permittivity estimation to further enhance diagnostic power.