Euterpe olerácea (açaı̧) as an alternative oral contrast agent in MRI of the gastrointestinal system: preliminary results

Using contrast agents is a common practice in medical imaging protocols. Paramagnetic properties of certain compounds present in contrast agents can affect magnetic resonance imaging (MRI) signals. For abdominal applications, they are usually injected, but may also be administered orally. However, their use as a routine technique is limited, mainly due to the lack of appropriate oral contrast agents. We herein present the preliminary characterization and results for implementation of Euterpe Olerácea (popularly named Açaı́) as a possible clinical oral contrast agent for MRI of the gastrointestinal tract. The pulp of Açaı́, a fruit from the Amazon area, presented an increase in T1-weighted MRI signal, equivalent to that of gadolinium-diethyltriamine pentaacetic acid, and a decrease in T2-weighted images. We looked for intrinsic properties that could be responsible for the T1 signal enhancement and T2 opacification. Atomic absorption spectra revealed the presence of Fe, Mn and Cu ions in Açai. The presence of such ions contribute to the susceptometric value found of χ = −4.83×10−6. This finding assents with the hypothesis that image contrast changes were due to the presence of paramagnetic material. The first measurements in vivo demonstrate a clear increase of contrast, in T1-weighted images, due to the presence of Açaı́. Consistently, the opacification in a T2-weighted acquisition was evident, revealing a good contrast on bowel walls of gastric tissues.