DIAGNOSIS OF URINARY-TRACT OBSTRUCTION IN DOGS USING DUPLEX-DOPPLER ULTRASONOGRAPHY

The ability of duplex Doppler ultrasonography to assist with the diagn osis of urinary tract obstruction was investigated in a study of 5 dog s with surgically induced, unilateral ureteral obstruction. The resist ive index (RI) of obstructed kidneys was compared to that of controls and to the contralateral unobstructed kidneys. The RI was also evaluat ed following relief of obstruction. On the basis of an RI measurement greater-than-or-equal-to 0.70 indicating obstruction, a sensitivity of 73% and a specificity of 77% was determined for the diagnosis of obst ruction with Doppler ultrasonography. Although mean RI was elevated in obstructed kidneys compared to controls, it was concluded that a high false-negative rate (27%) limits the clinical usefulness of Doppler u ltrasonography for the detection of urinary obstruction in dogs. The R I difference between obstructed and nonobstructed kidneys was also eva luated within individual animals, but the magnitude of difference betw een kidneys did not significantly improve the detection rate for obstr uction.