Assessment of gastric electrical impedance tomography by ¹³ C-acetate breath test for gastric retention evaluation

The gastric electrical impedance tomography (<i>g</i>EIT) has been assessed by the conventional¹³C-acetate breath test (BT) for gastric retention evaluation. The<i>g</i>EIT images the conductivity distribution of the gastric volumeVtmin the stomach. The<i>g</i>EIT was applied to seven healthy subjects during gastric emptying under the experimental conditions which are (i) frequencies of applied current is 30 kHz and 200 ml of 200 kcal liquid meal added with 100 mg sodium acetate- 1-¹³C. During the 90 min of measurement time, the<i>g</i>EIT measured each subject at five-minutes intervals, followed by the BT measurement. The<i>g</i>EIT calculated the gastric volumeVtm[%] based on the gastric conductivity distributionσobtained from the reconstructed image. Fifty percent completion time of gastric emptyingt50and¹³CO₂-peak exhalation timetmaxwere used as parameters to characterize gastric emptying during the BT. The<i>g</i>EIT images the conductivity distribution of the gastric volumeVtm[%] in the abdomen. The experimental results show gEIT is strongly correlated with BT between the values oftmaxandt50at frequency of 30 kHz, which indicates a low error in the gastric retention evaluation.<i>g</i>EIT proves to be a reliable, non-radioactive alternative for gastric retention evaluation.