Optimization of pineapple juice amount used as a negative oral contrast agent in magnetic resonance cholangiopancreatography

To evaluate the potential variability of Manganese (Mn(2+)) in commercial pineapple juice (PJ) produced in different years and to identify the optimal Mn(2+) concentration in the correct amount of PJ to be administered prior to Magnetic Resonance Cholangiopancreatography (MRCP) in order to suppress the gastroduodenal (GD) liquid signal. The Mn(2+) concentration in PJ produced in different years was defined using Atomic Absorption Spectrometry. The optimal Mn(2+) concentration and the amount of PJ, were estimated in an in-vitro analysis, and were then prospectively tested in a population of patients who underwent MRCP. The results were compared with those achieved with the previous standard amount of PJ used in a similar population. The concentrations of Mn(2+) in commercial PJ produced in different years did not differ. A total amount of 150 ml (one glass) of PJ having a high Mn(2+) content (2.37 mg/dl) was sufficient for the suppression of the GD liquid signal, despite the additional dilution caused by GD liquids since it led to a final concentration of Mn(2+) of 0.5–1.00 mg/dl. The optimized single-dose oral administration of 150 ml (approximately one glass) of PJ having a high Mn(2+) concentration prior to MRCP was adequate to guarantee the correct amount of Mn(2+) to suppress the GD signal.