Three-dimensional ultrasonography of the gastric antrum in patients with functional dyspepsia

Background: We have developed and validated a three-dimensional ultrasound system for transabdominal imaging. The aims of this study was to evaluate its applicability in scanning and volume estimation of the gastric antrum in humans. Method: Twenty patients with functional dyspepsia and 20 healthy controls, comparable with regard to gender, age, and smoking habits, agreed to be scanned while ingesting 500 ml of meat soup. A mechanical scanner with a 3.25-MHz transducer coupled to a tilting motor provided in 3 sec multiple images of the antrum during fasting and 1, 10, and 30 min postprandially. On a Unix work station planar contours of the antrum were selected and drawn manually before organ reconstruction and volume computation. Results: Two volume scans of 160 could not be analyzed due to air in the antrum. Up to 5 cm proximal to the pylorus, volumes could be computed in 95% of fasting samples and in 98% of postprandial samples, versus 8% and 75%, respectively, up to 7 cm proximal to the pylorus. We found no significant differences in antral volumes between dyspeptic patients and controls, either fasting or postprandially. Fasting antral volumes in Helicobacter pylori-positive dyspeptics were smaller than in H. pylori-negative patients (P = 0.02). Conclusions: Three-dimensional ultrasonography by use of a tilting motor makes non-invasive volume estimation of the gastric antrum possible without making assumptions about its geometry. In the present material no difference was found in antral volumes between patients with functional dyspepsia and controls. It is possible that fasting antral volumes in dyspeptic patients are dependent on H. pylori status.