Diuretic Ultrasound. A Non‐invasive Technique for the Assessment of Upper Tract Obstruction

A study was made of the diagnostic reliability of renal ultrasound with a diuretic in the evaluation of upper tract obstruction. The test comprised an initial renal ultrasound examination followed by the intravenous injection of 250 ml physiological saline with 40 mg frusemide; further ultrasound scans were carried out from 5 to 150 minutes later. A total of 67 patients was studied and the results were compared with those of diuretic intravenous urography, diuretic renography and, in some cases, the Whitaker test. Dynamic ultrasound with a diuretic showed a sensitivity of 94%, specificity of 94%, positive predictive value of 91% (obstructive), negative predictive value of 96% (non-obstruction) and a total diagnostic capacity of 94%.