title: Diagnostic accuracy of neonatal kidney ultrasound in children having antenatal hydronephrosis without ureter and bladder abnormalities.
abstract: OBJECTIVE
  To determine the diagnostic accuracy of anteroposterior renal pelvic diameter (APD) measurement and the society for fetal urology (SFU) grading in neonatal ultrasonography (USG) for detecting uropathy in newborns having antenatal isolated hydronephrosis (IH), characterized by hydronephrosis without ureter and bladder abnormalities, and to study time to resolution and factors predicting resolution of insignificant hydronephrosis.
  
  
  METHODS
  Ninety-six healthy newborns (129 kidneys) with IH, who underwent USG at age 7-30 days and voiding cystourethrography (VCUG) in conjunction with diuretic renography (DR) if APD > 10 mm or SFU grade 3-4 in neonatal USG, and at least a 12-month follow-up were divided into significant and insignificant hydronephrosis using the combined data of sequential USG, VCUG, and DR as the reference standard.
  
  
  RESULTS
  Areas under the receiver operating characteristic plots (95 % CI) were 0.86 (0.79-0.94) versus 0.81 (0.73-0.89); p = 0.08, and 87.6 versus 79.8 % of cases were correctly classified, for APD ≥ 16 mm versus SFU grade 4, respectively. Ureteropelvic junction obstruction (UPJO) was the most common uropathy diagnosed. Of 85 kidneys with insignificant hydronephrosis, 57 underwent spontaneous resolution. The resolution rates were 24, 40, and 68 % at age 6, 12, and 24 months, respectively. APD was the only independent factor predicting resolution with the hazard ratio of 0.83 (95 % CI 0.74-0.92; p = 0.001).
  
  
  CONCLUSIONS
  In IH, neonatal USG was a useful diagnostic tool to detect uropathy, mainly UPJO. Further investigation should be recommended when APD ≥ 16 mm or SFU grade 4.
authors.affiliation: Division of Nephrology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand. pornpimol.r@chula.ac.th.
authors.forename: Pornpimol
authors.initials: P
authors.lastname: Rianthavorn
authors.affiliation: Division of Nephrology, Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand.
authors.forename: Sorawan
authors.initials: S
authors.lastname: Limwattana
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging*; D007231:Infant, Newborn; D007668:Kidney / Q000000981:diagnostic imaging*; D007682:Kidney Pelvis / Q000000981:diagnostic imaging; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013997:Time Factors; D014463:Ultrasonography; D014513:Ureter / Q000002:abnormalities; D001743:Urinary Bladder / Q000002:abnormalities
keywords: Anteroposterior renal pelvic diameter; Diagnostic accuracy; Isolated hydronephrosis; Resolution; Society for fetal urology grading system