Effects of Anatomical Variations on Body Surface Gastric Mapping

The contractions of the stomach are governed by an electrophysiological event that can be detected noninvasively from the body-surface. Diagnosis of gastric motility disorders remains challenging due to the limited information provided by symptoms and standard electrogastrography (EGG). Body-surface gastric mapping (BSGM) is a novel technique that measures the resultant body-surface potentials using an array of multiple cutaneous electrodes. However, there is no established protocol to guide the placement of the mapping array and to account for the effects of biodiversity on the interpretation of gastric BSGM data. This study aims to quantify the effect of anatomical variation of the stomach on body-surface potentials. To this end, 44 subject specific models of the stomach and torso were developed. Anatomical parameters such as the Euclidean distance from the xiphoid process (88.1 ± 21.9 mm), orientation relative to the axial plane (202.8 ± 14.0°) and tissue volume (47.5 ± 29.5 mL) were quantified. Electrophysiological simulations demonstrated strong correlation (0.73 ± 0.16) between stomach and body-surface activities, with variations in the location of maximum amplitude relative to the xiphoid process (103.7 ± 44.2 mm). In general, there was an agreement between the location of the stomach and the location of the maximum amplitude, and an extended coverage was required to account for the biodiversity. The findings of this study will aid BSGM electrode array design and placement protocol in clinical practices.