title: Initially Asymmetrical Function on MAG3 Renography Increases Incidence of Adverse Outcomes.
abstract: OBJECTIVE
  To discriminate pathological from physiological hydronephrosis (99m)Tc-mercaptoacetyltriglycine (MAG3) diuretic renography is a fundamental imaging modality. Initial asymmetrical differential function or decreasing function on serial MAG3 scans is a classic surgical indication. However, prognostic evidence supporting this is limited. Therefore, we examined the association between initial function and outcomes. We hypothesized that patients with initially asymmetrical function would have higher odds of functional decline, and experience symptoms and surgical intervention compared to patients with initially symmetrical scans.
  
  
  METHODS
  We retrospectively reviewed the charts of 1,124 pediatric patients with hydronephrosis seen at Stollery Children's Hospital from 2000 to 2014. A total of 387 cases of unilateral ureteropelvic junction obstruction were grouped by initial postnatal differential function with asymmetrical defined as a greater than 10% difference in relative function. Postnatal surveillance, followup MAG3 results, pyeloplasty rates and post-pyeloplasty outcomes were compared.
  
  
  RESULTS
  Of 387 patients 143 (37%) had initially asymmetrical function. Of those undergoing MAG3 scan surveillance 17% experienced a 10% or greater decline in ipsilateral differential function vs a 6% rate of function loss in the initially symmetrical group (OR 3.2, 95% CI 1.6-6.4, p = 0.0008). The overall pyeloplasty rate in patients with asymmetrical and symmetrical function was 27% and 16%, respectively (OR 1.9, 95% CI 1.1-3.2, p = 0.013). Patients with initially asymmetrical function had an increased rate of pyeloplasty secondary to symptoms compared to those with initially symmetrical function (16% vs 8%, OR 2.1, 95% CI 1.1-4.0, p = 0.019). Mean time to functional decline and pyeloplasty was 19 and 17 months, respectively.
  
  
  CONCLUSIONS
  Patients with initially asymmetrical differential function had increased ORs for subsequent renal decline, symptom onset and pyeloplasty.
authors.affiliation: Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Assmus
authors.affiliation: Division of Urology, Department of Surgery, Stollery Children's Hospital, Edmonton, Alberta, Canada.
authors.forename: Darcie A
authors.initials: DA
authors.lastname: Kiddoo
authors.affiliation: Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Hung
authors.affiliation: Division of Urology, Department of Surgery, Stollery Children's Hospital, Edmonton, Alberta, Canada. Electronic address: pmetcalf@ualberta.ca.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Metcalfe
mesh_terms: D006801:Humans; D006869:Hydronephrosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015994:Incidence; D007223:Infant; D007674:Kidney Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D007677:Kidney Function Tests; D011866:Radioisotope Renography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D017263:Technetium Tc 99m Mertiatide; D013997:Time Factors
chemical_list: D019275:Radiopharmaceuticals; D017263:Technetium Tc 99m Mertiatide
keywords: diagnostic imaging; hydronephrosis; kidney; kidney function tests; technetium Tc 99m mertiatide