Evaluation of contrast dose reduction for excretory urography using computed radiography

We prospectively investigated whether performing excretory urography by computed radiography (CR) - with CR's broader dynamic range and potential for post-processing - would permit lower contrast dose while maintaining usual image quality. The rationale for this experiment was to evaluate whether CR had potential in reducing the risks and costs associated with urography. Sixty sequential patients were randomly assigned to undergo computed urography with either our full (282 mg I/kg body weight) or half our usual dose (141 mg I/kg body weight) of intravenous 60% diatrizoate meglumine. Three blinded observers judged automatically post-processed full dose tomograms and KUBs as qualitatively superior to both automatically post-processed and individually, interactively post-processed half dose images. Thus, post-acquisition image manipulation could not fully compensate for diminished image quality due to contrast dose reduction.