CT urography in the evaluation of urinary tract disease

The purpose of this study was to evaluate the efficacy of using limited CT through the kidneys following excretory urography in selected situations.

Within 2 h of excretory urography 568 patients had add-on CT without using additional contrast medium. In 487 patients with hematuria the results of the combined studies were compared with blinded prospective interpretations of each. In addition 81 patients had add-on CT for specific urographic questions.

Of the 345 renal parenchymal masses seen on CT in both groups, only 185 were detected prospectively on excretory urography. For the 81 patients who had CT because of abnormalities seen on excretory urography, including 54 with pseudotumors, findings were clarified and the correct diagnosis made. In 27 of 30 patients with lesions in the collecting system the lesions were detected only on excretory urography.

Excretory urography followed by limited CT increases the diagnostic accuracy for detecting, characterizing, or ruling out urinary tract disease by combining the high sensitivity of traditional excretory urography for detecting lesions in the collecting system and ureter with the high accuracy of CT for parenchymal and perinephric lesions without an additional patient visit or additional contrast medium. Because it leaves so few unanswered questions, the combination of standard excretory urography and limited CT is an excellent screening study in selected situations. It can be performed quickly, at controlled cost, is highly accurate, and is convenient for the patient, the referring physician, and the examining department.