Application of Black Tea as a Negative Oral Contrast in Magnetic Resonance Cholangiopancreatography (MRCP)

Obiective To investigate the feasibility of using black tea as a gastrointestinal oral negative contrast agent to null the signal from fluid in bowel during MR cholangiopancreatography (MRCP). Methods ① 15 different drinks were scanned with MRCP, T2-map and T1-map in vitro to identify the most suitable drink for MRCP. ② 10 volunteers were scanned by MRCP prior to and 5, 10, 15 min after tea consumptions to identify the optimal delay time. ③ 20 patients were scanned with MRCP prior to and 5 min after tea consumptions. The signal intensity (SI) and signal-to-noise ratio (SNR) of stomach, duodenum, liver-parenchyma, common bile duct (CBD), pancreatic duct (PD) and gall bladder (GB); the singal loss of stomach and duodenum; and the image quality of ampulla of vater (AV), intrahepatic ducts (IHD), hepatic duct, CBD, PD and GB were analyzed with Siemens Workstation. Results ①Lipton black-tea was identified as the optimal drink in vitro. ② There were no significant differences in MRCP among the 3 delay times in volunteer tests. ③ The SI, SNR and SI loss of stomach and duodenum, and the image quality of CBD, PD, GB and AV showed a significant improvement of MRCP after tea consumptions (P<0.05). But tea consumptions made no significant differences in the image quality of IHD and hepatic duct, and the SI and SNR of liver, CBD, GB and PD (P>0.05). Conclusion As a simple, cheap and safe drink, black tea can be widely used to reduce signal intensity of gastrointestinal tract and provide improved image of MRCP.