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Simulation and analysis of spatio-temporal maps of gastrointestinal motility.

Lammers WJ, Cheng LK - Biomed Eng Online (2008)

Bottom Line: Longitudinal contractions were not detected at all.Combinations of circular and longitudinal contractions were, to a limited extent detectable at a point in space and time.This approach could be useful to determine characteristics of contractions under a variety of circumstances.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Faculty of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates. wlammers@smoothmap.org

ABSTRACT

Background: Spatio-temporal (ST) maps provide a method for visualizing a temporally evolving and spatially varying field, which can also be used in the analysis of gastrointestinal motility. However, it is not always clear what the underlying contractions are that are represented in ST maps and whether some types of contractions are poorly represented or possibly not at all.

Methods: To analyze the translation from stationary or propagating rhythmic contractions of the intestine to ST maps, a simulation program was used to represent different patterns of intestinal contraction and to construct their corresponding ST maps. A number of different types of contractions were simulated and their ST maps analyzed.

Results: Circular strong contractions were well represented in ST maps as well as their frequency and velocity. Longitudinal contractions were not detected at all. Combinations of circular and longitudinal contractions were, to a limited extent detectable at a point in space and time. The method also enabled the construction of specific ST-patterns to mimic real-life ST maps and the analysis of the corresponding contraction patterns.

Conclusion: Spatio-temporal simulations provide a method to understand, teach and analyze ST maps. This approach could be useful to determine characteristics of contractions under a variety of circumstances.

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Related in: MedlinePlus

Inverse analysis of an experimentally recorded ST map. Panel A displays an ST map obtained fluoroscopically from a mouse in vivo (modified from [13] and used with permission from The American Physiological Society). A selected window (dashed square) is magnified at right (inset). The overall pattern is that of series of frequent and regular contractions in the duodenum. Two arrows indicate principle axes of the patterns; one with a steep slope ('a') and a second with a more gradual slope ('b'). Panel B displays a simple type of a simulated contraction pattern in which a burst oscillated at a width and a frequency similar to that in panel A. These oscillatory contractions also propagated in the aboral direction as indicated by arrow 'a' with a slope similar to that in the inset. Arrow 'b' however is horizontal as all oscillations occur at the same time, implying that the in vivo contractions did not occur simultaneously. In panels C, the contractions oscillated and propagated in various sequences. In C1, the contractions did not contract simultaneously, but one after the other, stepping forward in the aboral direction (indicated by '1', '2' and '3'). With this scenario, slope 'a' is similar but slope 'b' is directed in the aboral direction, opposite to that measured in vivo (inset). Scenario C2, in which the contractions occurred in the opposite sequence ('3', '2' and '1'), does produce a slope 'b' similar to the original one. Scenarios C3 and C4 repeat scenarios C1 and C2 but with propagation in the oral direction, creating a different slope of arrow 'a'.
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Figure 6: Inverse analysis of an experimentally recorded ST map. Panel A displays an ST map obtained fluoroscopically from a mouse in vivo (modified from [13] and used with permission from The American Physiological Society). A selected window (dashed square) is magnified at right (inset). The overall pattern is that of series of frequent and regular contractions in the duodenum. Two arrows indicate principle axes of the patterns; one with a steep slope ('a') and a second with a more gradual slope ('b'). Panel B displays a simple type of a simulated contraction pattern in which a burst oscillated at a width and a frequency similar to that in panel A. These oscillatory contractions also propagated in the aboral direction as indicated by arrow 'a' with a slope similar to that in the inset. Arrow 'b' however is horizontal as all oscillations occur at the same time, implying that the in vivo contractions did not occur simultaneously. In panels C, the contractions oscillated and propagated in various sequences. In C1, the contractions did not contract simultaneously, but one after the other, stepping forward in the aboral direction (indicated by '1', '2' and '3'). With this scenario, slope 'a' is similar but slope 'b' is directed in the aboral direction, opposite to that measured in vivo (inset). Scenario C2, in which the contractions occurred in the opposite sequence ('3', '2' and '1'), does produce a slope 'b' similar to the original one. Scenarios C3 and C4 repeat scenarios C1 and C2 but with propagation in the oral direction, creating a different slope of arrow 'a'.

Mentions: The preceding series of analyses could be described as a type of 'forward' analysis in which a particular contraction is simulated to produce a corresponding ST map. The reverse, or 'inverse' scenario can also be performed. This was done using an experimental recording from a mice duodenum (Figure 6 panel A) in which the contractions of the duodenum were measured in vivo by fluoroscopy [13]. The inset shows a magnified view of this ST map displaying a regular pattern of contractions. The aim of this simulation was to generate an ST map that would mimic as close as possible this real life ST map. From the original recording, it is clear that the contractions were frequent and regular, and there were two principal components to ST maps as shown by the arrows in panel A. The axis shown by arrow 'a' provides an indication of the speed of the global movement of the waves, while the axis indicated by arrow 'b' indicates the degree of regularity or delay between neighboring contractions.


Simulation and analysis of spatio-temporal maps of gastrointestinal motility.

Lammers WJ, Cheng LK - Biomed Eng Online (2008)

Inverse analysis of an experimentally recorded ST map. Panel A displays an ST map obtained fluoroscopically from a mouse in vivo (modified from [13] and used with permission from The American Physiological Society). A selected window (dashed square) is magnified at right (inset). The overall pattern is that of series of frequent and regular contractions in the duodenum. Two arrows indicate principle axes of the patterns; one with a steep slope ('a') and a second with a more gradual slope ('b'). Panel B displays a simple type of a simulated contraction pattern in which a burst oscillated at a width and a frequency similar to that in panel A. These oscillatory contractions also propagated in the aboral direction as indicated by arrow 'a' with a slope similar to that in the inset. Arrow 'b' however is horizontal as all oscillations occur at the same time, implying that the in vivo contractions did not occur simultaneously. In panels C, the contractions oscillated and propagated in various sequences. In C1, the contractions did not contract simultaneously, but one after the other, stepping forward in the aboral direction (indicated by '1', '2' and '3'). With this scenario, slope 'a' is similar but slope 'b' is directed in the aboral direction, opposite to that measured in vivo (inset). Scenario C2, in which the contractions occurred in the opposite sequence ('3', '2' and '1'), does produce a slope 'b' similar to the original one. Scenarios C3 and C4 repeat scenarios C1 and C2 but with propagation in the oral direction, creating a different slope of arrow 'a'.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2254420&req=5

Figure 6: Inverse analysis of an experimentally recorded ST map. Panel A displays an ST map obtained fluoroscopically from a mouse in vivo (modified from [13] and used with permission from The American Physiological Society). A selected window (dashed square) is magnified at right (inset). The overall pattern is that of series of frequent and regular contractions in the duodenum. Two arrows indicate principle axes of the patterns; one with a steep slope ('a') and a second with a more gradual slope ('b'). Panel B displays a simple type of a simulated contraction pattern in which a burst oscillated at a width and a frequency similar to that in panel A. These oscillatory contractions also propagated in the aboral direction as indicated by arrow 'a' with a slope similar to that in the inset. Arrow 'b' however is horizontal as all oscillations occur at the same time, implying that the in vivo contractions did not occur simultaneously. In panels C, the contractions oscillated and propagated in various sequences. In C1, the contractions did not contract simultaneously, but one after the other, stepping forward in the aboral direction (indicated by '1', '2' and '3'). With this scenario, slope 'a' is similar but slope 'b' is directed in the aboral direction, opposite to that measured in vivo (inset). Scenario C2, in which the contractions occurred in the opposite sequence ('3', '2' and '1'), does produce a slope 'b' similar to the original one. Scenarios C3 and C4 repeat scenarios C1 and C2 but with propagation in the oral direction, creating a different slope of arrow 'a'.
Mentions: The preceding series of analyses could be described as a type of 'forward' analysis in which a particular contraction is simulated to produce a corresponding ST map. The reverse, or 'inverse' scenario can also be performed. This was done using an experimental recording from a mice duodenum (Figure 6 panel A) in which the contractions of the duodenum were measured in vivo by fluoroscopy [13]. The inset shows a magnified view of this ST map displaying a regular pattern of contractions. The aim of this simulation was to generate an ST map that would mimic as close as possible this real life ST map. From the original recording, it is clear that the contractions were frequent and regular, and there were two principal components to ST maps as shown by the arrows in panel A. The axis shown by arrow 'a' provides an indication of the speed of the global movement of the waves, while the axis indicated by arrow 'b' indicates the degree of regularity or delay between neighboring contractions.

Bottom Line: Longitudinal contractions were not detected at all.Combinations of circular and longitudinal contractions were, to a limited extent detectable at a point in space and time.This approach could be useful to determine characteristics of contractions under a variety of circumstances.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Faculty of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates. wlammers@smoothmap.org

ABSTRACT

Background: Spatio-temporal (ST) maps provide a method for visualizing a temporally evolving and spatially varying field, which can also be used in the analysis of gastrointestinal motility. However, it is not always clear what the underlying contractions are that are represented in ST maps and whether some types of contractions are poorly represented or possibly not at all.

Methods: To analyze the translation from stationary or propagating rhythmic contractions of the intestine to ST maps, a simulation program was used to represent different patterns of intestinal contraction and to construct their corresponding ST maps. A number of different types of contractions were simulated and their ST maps analyzed.

Results: Circular strong contractions were well represented in ST maps as well as their frequency and velocity. Longitudinal contractions were not detected at all. Combinations of circular and longitudinal contractions were, to a limited extent detectable at a point in space and time. The method also enabled the construction of specific ST-patterns to mimic real-life ST maps and the analysis of the corresponding contraction patterns.

Conclusion: Spatio-temporal simulations provide a method to understand, teach and analyze ST maps. This approach could be useful to determine characteristics of contractions under a variety of circumstances.

Show MeSH
Related in: MedlinePlus