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Kidney Week

Abstract: FR-PO1100

Mercaptoacetyltriglycine Scan vs. Functional Magnetic Resonance Urography: A Comparison and Long-Term Follow-Up of Clinical Outcomes

Session Information

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology

Authors

  • Viteri, Bernarda, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
  • Khrichenko, Dmitry, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
  • Calle-Toro, Juan S., Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
  • Otero, Hansel J., Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
Background

Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) are the leading cause of End Stage Renal Disease in children. Obstructive uropathy (OU) presenting with urinary tract dilation (UTD) is one of the most common forms of CAKUT. While there is no gold standard for OU evaluation or clear cutoffs for surgical intervention, functional imaging evaluation is recommended to help the decision making process. In children, functional Magnetic Resonance Urography (fMRU) is increasingly used because of its superior anatomic detail when compared to the most widely used MAG3 nuclear medicine renal scan (RS). However, there is not enough data to assure that fMRU-based differential renal function is equivalent to RS results. Here we compare the functional results of fMRU and RS in a pediatric cohort presenting with UTD.

Methods

This is an IRB-approved retrospective review of 37 out of 988 (3.75%) fMRUs performed in 735 children (0-21 yrs) at our institution between 2007 and 2017, which had an accompanying RS within 6-months and with no interval surgical intervention.

Results

The 37 unique patients (15 F, 25 M) had a median age: 6 months (range: 2mo-19y) and; 24% were caucasian. The majority (26/37, 70.3%) presented with UTD P3. Main diagnoses included uretero-pelvic junction obstruction (UPJO) in 21/37, megaureter (5/37) and duplex kidney (4/37). Differential renal function (DRF) was obtained from each test and 14 fMRU and 12 RS patients were grouped as normal but there was no significant agreement between tests in the dilated groups (p= 0.135). Only 7/33 (21%) patients had concordant (<5% DRF difference) DRF from fMRU and RS. Upon evaluating obstruction determinants fMRU was found to be 88.24% specific and 38.10% sensitive with 69.09% accuracy (95% CI 55.19-80.86). 2/19 patients who had follow up for a mean of 3 years (range 6mo-9 years) had elevated BP. eGFR was found to be >100mL/min/1.73m2 consistent with normal renal function at follow-up in 15 patients.

Conclusion

The differential renal function determined by RS and fMRU in children is discordant in a majority of cases with significant agreement limited to those deemed normal in both modalities. Using RS as the gold standard, fMRU was found to be 88.24% specific though average sensitivity in determining obstruction. Overall cohort did not present adverse outcomes after a mean 3 years follow up.

Funding

  • Other NIH Support