Elastic Properties of the Isolated Perfused Porcine Duodenum

Abstract

The aim was to investigate elastic wall properties of the isolated perfused porcine duodenum using manometry and impedance planimetry. Distension of an intraluminal balloon with definite pressure steps of 0.5, 1.0, 2.0, 3.0 and 5.0 kPa was done with simultaneous recording of balloon pressure and balloon cross-sectional area (Bcsa). Wall thickness of the relaxed intestine was estimated from measurement of tissue density. The elastic wall parameters were calculated from these measurements. Balloon inflation elicited a phase of rapid Bcsa increase followed by an accommodation phase of slow Bcsa increase. At steady state, the circumferential and the radial wall stress increased as linear functions of the applied balloon pressure, while the circumferential and the radial wall strain increased nonlinearly. The incremental elastic moduli increased exponentially. Our model allows the study of passive biomechanical wall properties of the intact duodenum. The duodenal wall showed qualitatively and also quantitatively an elastic nature.

Viscoelastic properties and muscular function of the human anterior vaginal wall

“…Despite the frequent occurrence of such disorders, surprisingly few studies have been undertaken to analyze the elastic properties, as well as the muscular function, of the vaginal wall in humans. Measurement of elastic wall properties is becoming increasingly important in studies of distensible organs, since they may reflect physiological and pathological function [2,3].…”

Versatile Software System for Analysis of Gastrointestinal Pressure Recordings

“…The program has been applied on pres sure recordings from the stomach, duode num, and for more special purposes such as modality analysis of rectal pressure activity and radial analysis of duodenal pressure re cordings [1,5,6,9,10]. Furthermore, it is a platform for further development, such as a special algorithm for elimination of artifacts in the pressure recordings.…”

Impedance Planimetry: A New Approach to Biomechanical Intestinal Wall Properties

“…Furthermore, the name impedance planimetry was proposed for the technique because it is based on impedance measurements and because CA is a two-dimensional variable, a measure of the plane. This new impedance planimeter has now been used in several gastrointestinal studies [27][28][29][30][31]. Table 1 gives a survey of the investigations presented so far with field gra dient principle/impedance planimetry.…”

“…Circumferential wall tension = intraluminal radius (R) X trans mural pressure difference (the Law of La place), where R = the square root of Bcsa X 7t_' [28], If the thickness of the wall (h) is measured, the wall stress (S) can be calculated from the formula [2,31]: S = T X h_l. Compliance = 8Bcsa X 8P"1 or rigidity = 8P X SBcsa-' [15,16,21,22], Pressure elastic modulus (wall stiffness) Ep = 8P X R 8R"1 [1,2], If the thickness of the wall is measured, other parameters such as Young's elastic modulus and incremental elastic modulus can be calculated [1,2].…”