Quantitative analysis of peristaltic and segmental motion in vivo in the rat small intestine using dynamic MRI

Abstract

Conventional methods of quantifying segmental and peristaltic motion in animal models are highly invasive; involving, for example, the external isolation of segments of the gastrointestinal (GI) tract either from dead or anesthetized animals. The present study was undertaken to determine the utility of MRI to quantitatively analyze these motions in the jejunum region of anesthetized rats (N ‫؍‬ 6) noninvasively. Dynamic images of the GI tract after oral gavage with a Gd contrast agent were acquired at a rate of six frames per second, followed by image segmentation based on a combination of three-dimensional live wire

Effects of feeding on in vivo motility patterns in the proximal intestine of shorthorn sculpin (Myoxocephalus scorpius)

“…Overall outlines of the exteriorised intestines are displayed below each ST map and each ST map is 20 min long (vertical axis). reduced after the administration of anaesthetic (Ailiani et al, 2009;Torjman et al, 2005), whereas, in pigs, the frequency of slow waves varied depending on the type of anaesthetic used (Tachecí et al, 2013). MS222, the general anaesthetic used in this study, has been shown to impair cardiovascular performance in fish (Hill et al, 2002;Houston et al, 1971).…”

“…Often, different patterns dominate in different regions of the gut, but this may also depend on the fed state of the animal (Ailiani et al, 2009;Berthoud et al, 2002;Bogeski et al, 2005;Chen et al, 2013;D'Antona et al, 2001;Ferens et al, 2005;Hennig et al, 1997;Hennig et al, 1999;Hennig et al, 2010). Mixing and propulsion can be achieved by either non-propagating (e.g.…”

Advective mixing due to longitudinal and segmental contractions in the ileum of the rabbit

“…This motility is generally characterised by an initial and slight increase in organ diameter, followed by a contraction to approximately 75% its initial diameter, a lag phase, and a slow increase back to its original size. This general description of a segmental contraction has been observed in the canine (Bayliss and Starling, 1899), in the ileum of a cat (Krishnan, 1932), in the rat jejunum (Ailiani et al, 2009), and in the guinea pig jejunum (Gwynne and Bornstein, 2007), to name a few. Of note, is the observation that the compression phase is significantly more rapid than the relaxing phase.…”

“…See, for example, Ailiani et al (2009) and Thuneberg and Peters (2001). Here we model the simple situation where two segmental contractions occur with the same contraction depth and phase, at a distance d from one another.…”

“…Here we investigate the effect of four wall motions: (a) a longitudinal contraction in the oral direction, (b) a single segmental contraction, (c) two adjacent segmental contractions acting in synchrony, and (d) a combination of an oral longitudinal contraction and a single segmental one. The oral longitudinal contraction is defined from the experiments of Lammers (2005), while the segmental contractions are defined from data reported in literature (Bayliss and Starling, 1899;Krishnan, 1932;Ailiani et al, 2009;Gwynne and Bornstein, 2007). These motions were developed into a numerical model using the commercial CFD code ANSYS Polyflow.…”