Quantifying the impact of oral negative contrast agents in emergency magnetic resonance cholangiopancreatography: a histogram-based analysis of gadolinium and pineapple juice

Abstract Background Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive modality widely used to assess the biliary and pancreatic ducts. However, in emergency practice, rapid and confident interpretation may be hindered by high signal intensity from adjacent gastrointestinal fluid, which can obscure ductal anatomy and reduce diagnostic clarity. Despite the use of oral negative contrast agents to address this limitation, evidence remains scarce regarding which accessible and practical agent provides superior suppression effects in routine clinical settings. This study therefore compared gadolinium and pineapple juice as oral contrast agents using histogram analysis to identify the more effective approach for optimising MRCP image quality and enhancing diagnostic efficiency. Methods This prospective observational study included two groups of patients undergoing MRCP who received different oral contrast agents, Gadolinium solution and pineapple juice, administered immediately before scanning to suppress gastrointestinal signals. Image quality was assessed quantitatively and qualitatively. Quantitative measurements included signal intensity (SI), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR), obtained using RadiAnt DICOM Viewer software. Visual assessments were performed independently by board-certified radiologists with more than 20 years of experience. In addition, grayscale histogram-based analysis was performed using ImageJ. Data were analysed statistically using SPSS, including tests for data normality, group differences, and inter-observer agreement, with significance defined as p < 0.05. Results Histogram-based grayscale analysis was found to be superior to conventional SNR, SI, and CNR measurements. Both gadolinium and pineapple juice showed significant improvement in SNR, SI, and CNR values after oral administration in the extrahepatic ducts (p < 0.001). However, histogram analysis revealed a significant improvement only with gadolinium (p < 0.001), whereas pineapple juice showed no significant change. Conclusion Oral gadolinium provides more effective suppression of gastrointestinal signals compared with pineapple juice, particularly in emergency settings where immediate image optimisation is crucial. Furthermore, histogram-based grayscale analysis represents the most reliable and sensitive method for evaluating MRCP image quality.