A Colonic Marker Transit Study (CTMS) is one of the few objective ways to measure constipation in children. The basic principles are:
- ingestion of small markers
- a plain abdominal x-ray to check the location of these markers after a few days
- children with constipation will retain more markers within the bowel than children without constipation
In children, three clear patterns of have emerged i.e. normal transit, slow transit constipation (STC) and rectal evacuation disorder (RED).
In looking at hundreds of these CTMS images, we realised that these transit patterns on x-ray can be described mathematically. Using data modelling techniques, we have defined a parameter, the transit index (TI), that can be used to enrich reporting of CTMS. These pages describe the development and validation of the method.
How it started
Colonic transit marker studies are commonly done using radio-opaque markers. There are various methods that vary in the number of markers, ingestion protocol and number of xrays.
How it works
Transit index is based on combining weighted mean modelling of isotope methods with the gestalt approach of sector based methods. Mathematical modelling was used to identify the best predictor.
How to do it
TI is a measure of the central tendency of transit marker patterns. After modelling various measures of central tendency, we identified the arithmetic mean of weighted markers best corresponds to patterns of STC, RED or normal.
Who we are
We are paediatric surgeons and radiologists involved in the management of children with constipation.
Surgeons often view and interpret CTMS in clinic. We rely on the reporting of images by a radiology colleagues. In this project, we have worked together to improve the yield and utility of CTMS.