Acute renal obstruction: evaluation with intrarenal duplex doppler ultrasound

To assess the value of duplex Doppler ultrasound [DU] in diagnosis of acute renal obstruction, 50 patients with symptoms suggestive of renal colic were studied. Intravenous urography was done as a standard technique for diagnosis of renal colic. DU was done during the attack, with determination of the intrarenal resistive index [RI], and the difference between the resistive index of the affected kidney and the asymptomatic kidney [dRI] was calculated. 12 to 24 hours after treatment with non steroidal anti-inflammatory drugs [NSAIDs], DU was repeated determining the RI and the dRI. An RI >/- 0.70 and or dRI >/- 0.06 considered reliable cut-off values to diagnose acute renal obstruction. The results of DU were compared with the IVU findings. 13 patients were shown to be normal by IVU and 37 proved by IVU to have a unilateral renal obstruction with a normal opposite kidney. The mean RI in the affected kidneys during the attack of renal colic [0.72 +/- 0.06] was significantly higher than that in normal kidneys [0.60 +/- 0.05] [P < 0.001]. The mean dRI in patients with unilateral renal obstruction [0.08 +/- 0.03] was significantly higher than that in patients without obstruction [0.02 +/- 0.02] [P < 0.001]. 12 to 24 hours after treatment with NSAIDs, the mean RI of normal kidneys remains constant, while, the mean RI of the obstructed kidneys decreased to 0.65 +/- 0.04 and it remained significantly higher than that of normal kidneys [P < 0.001]. The mean dRI in patients with acute renal obstruction decreased to 0.06 ' 0.03 and again it was significantly higher than the mean dRI in normal patients. The sensitivity of the RI was 76% and the specificity was 79% with +ve predictive value of 68% and -ve predictive value of 85% during the attack of renal colic.The sensitivity of dRI was 81% and the specificity was 92% with +ve predictive value of 97% and -ve predictive value of 63%. 12 to 24 after the relive of pain, the sensitivity of the RI and of dRI decreased to 49% and 70% respectively while the specificity remained stable at 79% and 92% respectively. The +ve predictive value of RI was 58% and the -ve predictive value was 72%. The +ve predictive value of dRI was 96% and the -ve predictive value was 52%

Comparison of the accuracy of interventional radiology, diuretic ultrasonography and radionucleids studies in prediction of the prognosis of radiologically non functioning obstructed kidney

Twenty eight patients of unilateral radiologically non functioning obstructed kidneys were studied before treatment, and, after relieve of obstruction, by different radiological and imaging methods i.e. ultrasonography with diuretic ultrasound, radionucleides study, antegrade urography, retrogrode urography and laboratory investigations [Osmolality of urine, urinary ph, and split renal clearance]. The patients examined by I.V.U. after relieve of obstruction by 2 months and 4 months. Eight patients performed nephrectomy because of pyonephrosis and advanced back pressure noted by ultrasonography. The remaining 20 patients showed. after treatment good function in 10/20 [50%] patients, moderate function in 6/20 [30%] patients and non function in 4/ 20 [20%]. It was noted that the split clearance is the most accurate method with 100% accuracy. The renography and diuretic renography shows 100% accuracy in cases of dilated non obstructed and non perfused kidneys. The accuracy of ultrasonography and diuretic ultrasonography was 100% in mild hydronephrosis and when the change in pelvic surface area was from 60-80% after diuretic by 15 minutes