Açai juice as contrast agent in MRCP exams: qualitative and quantitative image evaluation

Abstract This works aims to assess images obtained with administration of açai juice as compared to a manufactured standard iron oxide-based contrast employed as negative oral agents in Magnetic Resonance Cholangiopancreatography (MRCP), employing qualitative and quantitative evaluation. The research was developed with 64 patients submitted to MRCP exams (on 2 days) in a clinic of Curitiba city (Brazil). First (day 1), a manufactured iron oxide-based contrast (A) was offered and later (day 2), açai juice (contrast B) was given to patients. Radiologists (R1 and R2) evaluated the images, classifying them by a score (1-4). In order to have a quantitative assessment, Image J free software was employed generating plots of gray levels against distance of a chosen area of the bile duct interest region. Evaluating images for contrast A, R1 furnished an average score of 3.52 and R2 of 3.27. For contrast B, R1 provided 3.44 and R2 3.38. Both evaluators considered image quality with contrast A adequate for 62 patients. R1 considered adequate for 62 and R2 for 60 patients when using açai juice. By taking same images for all patients with Image J, a quantitative analysis was obtained, resulting correlation coefficient of 0.986 between average curves of contrasts A and B. Thus, açai juice is an adequate alternative as contrast agent in MRCP exams. Image J was employed as a new method for quantitative investigation of image quality, presenting good agreement with medical opinion.

Development and validation of analytical methodology with focus on the qualification of powder mixers / Misturadores de pós/validação analítica; Espectrofotometria; Óxido férrico/quantificação; Lactose monoidratada/análise quantitativa

This study aims at developing an analytical procedure capable of quantifying the ferric oxide present in the mixture of ferric oxide/lactose monohydrate (0.4% w/w). The analytical procedure was checked for specificity, linearity, precision (system repeatability, procedure repeatability and intermediate precision), accuracy, stability of solutions and robustness of the procedure. The concentration of Fe (III) was determined by spectrophotometry at 480 nm based on calibration curves. The specificity was verified. The linearity was obtained in the range of 11.2 to 16.8 µg of ferric oxide/mL. The relative standard deviation (RSD) of the system repeatability, procedure repeatability and intermediate precision, were not more than 2%. The RSD of the accuracy values were less than 0.75%. The stability of the samples was checked over a 24 hours assay. In the robustness evaluation, the wavelength and the concentration of hydrochloric acid varied. The maximum absorbance deviation due to wavelength variation was 0.14 percent, and the maximum deviation due to the hydrochloric acid concentration variation was 2.4%, indicating that the concentration of hydrochloric acid is critical to the analysis of ferric oxide. The procedure developed was validated and is suitable to the performance qualification of powder mixers..

O objetivo deste trabalho foi desenvolver um método analítico capaz de quantificar o óxido férrico presente na mistura óxido férrico/lactose monoidratada (0,4% w/w). Verificou-se a especificidade, linearidade, precisão (repetibilidade do sistema, repetibilidade do método e precisão intermediária), exatidão, estabilidade das soluções e robustez. A concentração de Fe(III) foi determinada por espectrofotometria em 480 nm com base em curvas de calibração. Verificou-se a especificidade verificada. A linearidade foi obtida na faixa de 11,2 a 16,8 µg de óxido férrico/mL. O desvio padrão relativo (DPR) da repetibilidade do sistema, método e precisão intermediária foram inferiores a 2%. Os valores de DPR da exatidão foram inferiores a 0,75%. A estabilidade das amostras foi verificada ao longo de 24 horas de ensaio. Na avaliação da robustez variou-se o comprimento de onda e a concentração de ácido clorídrico. O desvio máximo de absorbância ao se variar o comprimento de onda foi de 0,14%, enquanto que para a concentração de ácido clorídrico o desvio foi de 2,4% para a concentração de 0,8 M. Assim, a concentração de ácido clorídrico é crítica para a análise de óxido férrico. O método desenvolvido foi validado e é adequado à qualificação do desempenho de misturadores de pós e granulados...