Imaging of gastric acidity scale by integration of pH-conversion model (pH-CM) into 3D-gastro electrical impedance tomography (3D-g-EIT).

The gastric acidity scale has been imaged by integration of the pH-conversion model (pH-CM) into 3D-gastro electrical impedance tomography (3D- g -EIT) under the influence of spatial mean hydrogen-specific conductivity σ H + . The pH-CM uses Debye-Hückel-Onsager (DHO) interionic equation, molar conductivity ratio, ω H + , viscosity η state (k) and relative permittivity ε state (k) in order to convert the imaged conductivity distribution σ to the pH distribution pH *. With the proposed integration, phantoms of empty (S 1), liquid storage (S 2 - S 4), and solid meal storage (S 5) states are measured to reflect the dilution state. In the case of empty (S 1), the artificial gastric juice is made based on 99.50% of H 2 O and 0.50% solution consisting of HCl (1.4263 g/L), KCl (0.8647 g/L), and NaCl (2.8559 g/L). In the case of the liquid storage (S 2 - S 4) state, 200 mL of H 2 O is added three times as a dilution of artificial gastric juice in each S 2 , S 3 , and S 4. In the solid meal storage (S 5) state, an acid solid meal is blended into the artificial gastric content. The modified constants, α , and β are calculated based on the variation of viscosity η state (k) and permittivity ε state (k) of each state. The conductivity of gastric-shape models in five states is studied in the simulation. In the experiments, the simulated models were measured as gastric phantoms. Integrating pH-CM into 3D- g -EIT successfully images the pH * in the simulations and experiments. As a result, the estimated acidity scale 〈 pH 〉 is inversely proportional to σ H + with mean pH error evaluation of simulations e ˆ pH (sim) and experiments e ˆ pH (sim) are 15.8% and 8.5%, respectively. • A new pH estimation 〈 pH 〉 based on a conversion model from hydrogen-specific conductivity 〈 σ H + 〉 to concentration H + • The imaging of artificial gastric pH distribution pH∗ by integrating 3D- g -EIT and DHO equation. • The evaluation of acidity scale 〈 pH 〉 based on gastric-shaped phantoms during empty, liquid, and solid storage states. [ABSTRACT FROM AUTHOR]