Summary
Introduction
Mercaptoacetyltriglycine (MAG-3) renogram is one of the gold standard diagnostic tools
of ureteropelvic junction obstruction (UPJO); however, there is no widely agreed indications
of pyeloplasty based on MAG-3 findings. In this study, we introduce a renogram scoring
system that can help improve the prognostic value of MAG-3 renogram and in the decision
making of pyeloplasty.
Patients and methods
We retrospectively reviewed consecutive pyeloplasties for antenatal hydronephrosis
from 2010 to 2020. A control group was included of non-operatively managed SFU grade
3 and 4. The initial renal ultrasound and preoperative MAG-3 Lasix renogram were reviewed
for differential renal function (DRF), type of renogram curve and tracer washout half-time
(T1/2). A ROC curve was used to evaluate the cut-off points that can be associated with
obstruction. A multivariate linear regression model was used to assess the best renogram
parameter that can predict surgical intervention.
Results
We included 188 patients with 209 renal units. The median age for pyeloplasty was
5.4 months. The mercaptoacetyltriglycine-Suspected Obstruction Scoring System (MAG-SOS)
was associated with pyeloplasty (AUC = 0.97, P < 0.001) (Figure A). A score of 5 is
100% specific for obstruction. 78% of units required surgical intervention had a MAG-SOS
score of≥5 while all units of the control group had a range of score 0–4. Using the
multivariate analysis, the MAG-SOS system showed to the only independent predictor
for pyeloplasty (HR = 0.03, p < 0.001).
Discussion
This study has some limitations. Firstly, the retrospective nature of the cohort;
however, all patients were reviewed by one investigator who was blinded to the line
of management. This is a single institutional study; therefor, this MAG-SOS should
be evaluated by other centers to ensure its efficiency. Lastly, the pyeloplasty decision
was taken by 3 different urologists; nevertheless, all of them adopt the same indications
which are similar to those of the Society for Pediatric Urology and the Canadian Urological
Association guidelines.
Conclusion

Graphical AbstractRoc curve shows the association between MAG-SOS and surgical intervention with possible
cutoffs.
Keywords
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Article info
Publication history
Published online: March 02, 2023
Accepted:
February 25,
2023
Received in revised form:
February 22,
2023
Received:
November 1,
2022
Publication stage
In Press Journal Pre-ProofIdentification
Copyright
© 2023 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.