Computer-supported analysis of continuous ambulatory manometric recordings in the human small bowel

Abstract

An algorithm has been developed for the offline analysis of prolonged manometric recordings in the upper small intestine of humans. Sample data are acquired in the human duodenum and jejunum six solid-state strain-gauge transducers mounted on a silicon catheter that is connected to a portable digital recording device. The data are sampled at 4 Hz and filtered. For accurate calculations, the filtered signals are converted to cubic B-spline functions of order four. Based on an exponential weighted moving average, a base-line is calculated from the signal. Contractions are recognised on the basis of thresholds for minimum amplitude and duration. The developed algorithm calculates properties of these contractions, such as amplitude, duration, area and a motility index. In addition, the program automatically recognises normal motor patterns of the fasted human small intestine, such as the migrating motor complex, and aids in the identification of the postprandial motor pattern. Motor patterns are defined in terms of properties such as contraction frequency and propagation. In a validation procedure using conventional manual analysis, the program correctly identifies the number of individual contractions with a 98% confidence interval and also correctly recognises 96% of phase 3 motor activity.

Role of duodenal mucosal nerve endings in the acid‐induced duodenogastric sensorimotor reflex: Effect of benzocaine in healthy humans

“…Phasic motility of the proximal stomach was quantified by calculating the motility index as reported before . Briefly, slow changes in baseline volume were determined after filtering out respiratory artifacts using a computerized algorithm.…”

Influence of duodenal acidification on the sensorimotor function of the proximal stomach in humans

“…In addition, changes induced by duodenal infusions were also quantified by calculating the differences between the mean intrabag volume during 5 min immediately before duodenal infusion or ingestion of the meal and during the defined periods. To evaluate the effect of duodenal infusion on the phasic contractility of the fundus, which corresponds to slow changes in baseline volume after filtering out respiratory artefact, a baseline reconstruction was performed by using a computerized algorithm (2). Consecutively, a motility index (MI) was calculated as the area between the signal and the baseline normalized over time (26).…”

Ambulatory gastrojejunal manometry in severe motility-like dyspepsia: lack of correlation between dysmotility, symptoms, and gastric emptying

“…On the basis of previous experiments which validated the recognition of individual contractions in the human gut by the computer program,14 an individual contraction was defined as pressure activity lasting for at least 1.25 seconds at 6 mm Hg and 0.6 seconds at 9 mm Hg above baseline pressure. Propagation of individual phasic pressure waves was calculated at the level of the jejunum: a contraction was considered to be propagated if it was recorded at all three channels of the second group of three sensors, thus propagating over at least 8 cm, within a time window that allowed a minimal velocity of 0.7 cm per second and a maximal velocity of 4 cm per second 17…”

“…The interdigestive period was divided into the classic phase 3, phase 2, and phase 1 motor activity with the aid of the computer algorithm according to well established criteria 1419 20 Even though the accuracy of the computer program in recognising small intestinal phase 3s is 96%,14 visual analysis was used to confirm correct identification of phase 3, phase 1, and phase 2. Antral phase 3s were always marked visually.…”