Functional oesophago-gastric junction imaging

Figure 1 Sketch of a conventional impedance planimetry probe with a single set of excitation (E) and sensing (S) electrodes for the measurement of cross-sectional area in the middle of the bag. D is the distance between the sensing electrodes.

Figure 2 Diagram showing multi-electrode probe by Andersen et al for measuring 5 CSAs in the porcine rectum.

Figure 3 Plot showing the changes in the CSAs at the proximal (P), middle (M) and distal (D) electrode pairs as the balloon is distended at a constant flow rate indicated by the increase in volume.

Figure 4 An example of how a probe which can measure 8 CSAs could profile the geometry of the narrowing region of a bodily sphincter.

Figure 5 Plot showing changes in the 8 measured CSAs during bag distension at 40 mL/min. CSA1 is the most distal and CSA8 is the most proximal.

Figure 6 Three dimensional reconstruction of the OGJ geometry in a human volunteer after distension in to a volume of 40 mL. All dimensions are in millimeters. Colour change is indicating increased radius.

Figure 7 Geometric profile of the porcine OGJ before and after the placement of 3 sutures in the OGJ. T indicates the point where wall tension was measured.