Ultrasound-determined geometric and biomechanical properties of the human duodenum

Methods based on cross-sectional ultrasound imaging may be valuable for assessment of biomechanical parameters in the duodenum in health and disease. In 12 healthy volunteers a specially designed duodenal bag containing a high-frequency ultrasound probe was inflated until the perception of moderate pain. The ultrasound images and bag pressures were recorded before and after administration of butylscopolamine. The duodenum approached a circular shape as the load was increased (P = 0.01). The tension-strain relations were exponential and the curve fitting constant alpha (stiffness) was 1.72 +/- 0.81 before and 1.13 +/- 0.22 after administration of butylscopolamine (P=0.5). In three subjects construction of stress-strain diagrams was possible. The wall thickness decreased after administration of butylscopolamine (P < 0.001). The wall thickness was nonhomogeneously distributed along the duodenal circumference, being thickest at high curvatures. In the future this may be useful for assessing the geometry, stiffness, remodeling, and mechanosensory properties in the duodenum and small intestine in health and disease.