On the differences between the BaSO4 particles and additives in media for the double contrast examination of the stomach.

Sizes and shapes of the particles in double contrast media for the stomach have been studied with scanning electron microscope. EZ-HD deviated most from the other media because of its large particles (even 70 micrometers in diameter) which were also variable in shape. The additives soluble in water or methanol raise the viscosity of the media considerably (with the exception of EZ-HD) thus lowering their greatest possible densities. The observations explain the differences in the results obtained with patients in clinical examinations with various contrast media.