The role of renal parenchyma to hydronephrosis area ratio in the evaluation of ureteropelvic junction obstruction in children

For the initial assessment and follow-up of patients with ureteropelvic junction obstruction (UPJO), we conducted this prospective study to assess the renal parenchyma to hydronephrosis area ratio (PHAR) in conjunction with the renal scan in patients who will undergo pyeloplasty. Patients who had visited the outpatient clinic for 2 years were diagnosed with UPJO, and fit the requirements for requiring surgical intervention were chosen. Before pyeloplasty and 3 months after surgery, PHAR and a renal isotope scan were conducted concurrently. Thirty-six patients were evaluated. After the operation, 31 (86.1%) cases improved and five (13.9%) cases did not improve. There was a significant change in all parameters at 3 months postoperatively as the mean T½ has significantly decreased (25.22±2.49 vs. 17.57±3.84). Also, there was a significant increase in the mean parenchymal thickness (9.42±4.92 vs. 15.12±4.86), glomerular filtration rate of the affected kidney (34.31±3.31 vs. 48.32±6.99) split renal function (37.30±3.80 vs. 44.03 ±4.11) and PHAR (0.86±0.30 vs. 2.45±0.93) at 3 months postoperative. PHAR postoperatively shows a positive correlation with parenchymal thickness, glomerular filtration rate of the affected kidney, and renal split function, while there is a negative correlation with T½. PHAR is a potential noninvasive measure that may be evaluated during ultrasonography assessment to aid in predicting future surgical needs for UPJO and for postpyeloplasty follow-up in pediatric patients.