Transcutaneous Intraluminal Impedance Measurement for Minimally Invasive Monitoring of Gastric Motility: Validation in Acute Canine Models

Figure 1

(a) The TIIM principle shown schematically: a small electrical signal is emitted from the TIIM transducer intraluminally from within the stomach after ingestion. The transducer is contained within an expandable pill that swells within the stomach, thus preventing it from being expelled through the pylorus for a prolonged amount of time (days). The attenuation dynamics of the electrical signal across the gastric and extraluminal tissue is measured from the skin via external cutaneous electrodes. The TIIM signals are measured using a standard multichannel bioelectric amplifier (electrogastrograph). After a predetermined amount of time (depending on the materials used), the long-term gastric-retentive enclosure disintegrates and the resulting smaller constituents of the pill individually exit the gastrointestinal tract via natural peristalsis. The TIIM components in the figure are deliberately zoomed in. (b) TIIM gastric-retentive pill design: (1) electronic oscillator circuit; (2) capsule body; (3) assembled capsule; (4) superabsorbent granules; (5) capsule and granules inside a liquid-permeable mesh; (6) dissolvable pill containing the meshed capsule; (7) TIIM gastric-retentive pill; (8) pill expanded in water; and (9) test dish. Horizontal and vertical 1 cm scales are depicted at the bottom left corner.

(a)

(b)