title: [Application of black tea as a negative oral contrast in magnetic resonance cholangiopancreatography (MRCP)].
abstract: OBJECTIVE
  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
  (1) Lipton 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Radiology , West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: He-Han
authors.initials: HH
authors.lastname: Tang
authors.forename: Bin
authors.initials: B
authors.lastname: Song
authors.forename: Zi-Ring
authors.initials: ZR
authors.lastname: Huang
authors.forename: Hui
authors.initials: H
authors.lastname: Yao
mesh_terms: D001628:Beverages; D049448:Cholangiopancreatography, Magnetic Resonance; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D013662:Tea
chemical_list: D003287:Contrast Media; D013662:Tea