The effect of patient positioning on mural filling defects during double contrast cystography.

Different radiographic findings may be observed during double contrast cystography due to patient positioning affecting the distribution of positive and negative contrast media. A mass lesion was created in the urinary bladder of a canine cadaver to allow evaluation of the effect of patient positioning on the appearance of a mass during double contrast cystography. The mass appeared as a filling defect only on those views where positive contrast medium surrounded the mass. Otherwise, the mass appeared as a summation. Additionally, a patient is described illustrating the effect of patient positioning on detecting mural filling defects during double contrast cystography.