Evaluation of endoluminal contrast materials of the MR examinations of the gastrointestinal tract by using a plastic model

Purpose: Evaluation of different gastrointestinal endoluminal MR contrast materials

Material and methods:

Authors constructed a plastic container holding 6 plastic cups. The signal-to-noise ratio (SNR) of over fifteen different materials (commonly used contrast materials, juices, iron containing solutions, cocoa) was measured by T1- and T2-weighted spin-echo sequences in a 1T MR unit. The results were compared in tables and demonstrated by figures.

Results: The juices containing metallic components had high signal intensity (SI) on T1-weighted images (SNR>97), while on T2-weighted images showed moderate to high SI (SNR>61.43) except the rosehip syrup (SNR=14) and a special blackcurrant extract (SNR=4.83), which were of low SI. The SI of the iron (III)-desferrioxamine solution increased on T1-weighted images (SNR: 54.95–122.62) and decreased on T2-weighted images (SNR: 117.24–59.05) in direct proportion to its iron concentration. Cocoa drink (50g cocoa-powder/liter milk) had low to moderate SI on both the T1- and T2-weighted images (SNR=40.46 and 27). Increasing the cocoa-powder quantity (20–100g/liter water) the SI on T1-weighted images did not increase too much (SNR: 20.6–34.56) but on T2-weighted images we noticed a significant decrease of the SI (SNR: 84.29–34.25) and a susceptibility artifact appeared on both T1- and T2-weighted images.

Conclusion: On the base of the experimental results rosehip syrup, blackcurrant extract, iron (III)-desferrioxamine and as best of all cocoa were selected for further examinations to determine the optimal concentration, sequence parameters and additives providing stability and good bowel distention.