Difference in results of ultrasonography and diuretic renograms after pyeloplasty in children with unilateral ureteropelvic junction obstruction

Purpose: Controversies persist on pyeloplasty follow-up, and the aim of this study was to assess the differences and interpretations in results of postoperative ultrasonography and diuretic renograms. Materials and Methods: The study population consisted of 46 patients who underwent pyeloplasty between 1997 and 2003. The average patient age was 7.0 months (range, 2-36 months). Serial changes in hydronephrosis were evaluated by consecutive ultrasonography at 1, 4, 10, and 24 months after pyeloplasty, and a diuretic ^99mTc-MAG3 renal scan was performed 4 months after the surgery. Results: Ultrasonography showed that 11 (24%), 27 (59%), 35 (76%), and 39 (89%) patients had improved in hydronephrosis at 1, 4, 10, and 24 months after pyeloplasty, respectively. Diuretic renal scans showed that of 27 patients who showed improvements in hydronephrosis at 4 months after pyeloplasty, only 17 (63%) had improved excretion and 22 (81%) had preservation of different renal function (DRF). Among 19 patients with persistent or worsened hydronephrosis, 10 (53%) had improved excretion and 13 (68%) had preserved DRF. Conclusions: The results of ultrasonography and diuretic renal scan studies can differ in the same case after pyeloplasty. We recommend that improvements in hydronephrosis be assessed individually by ultrasonography, renal scans, and clinical status to determine surgical outcomes.