There is a lack of evidence in the literature correlating prenatal and postnatal urinary tract (UT) dilation pathology because classification systems vary, differing descriptive terms are used, and because dilation is a dynamic process and uropathies present a spectrum of severity. This paper summarises the collaboration of eight societies involved with the management of patients with UT dilation (American College of Radiology, American Institute of Ultrasound in Medicine, American Society of Paediatric Nephrology, Society for Foetal Urology, Society for Maternal-Foetal Medicine, Society for Paediatric Urology, Society for Paediatric Radiology, and Society of Radiologists in Ultrasound). Their aim was to establish a unified system for classifying UT dilation so that management and outcome measures can also be unified. The paper describes in detail some of the dilemmas and discrepancies and lists the recommendations as a result of the consensus discussion.

Recommendation 1: There should be consistent use of the term “UT dilation” with ultrasound parameters listed in a table in the paper.
Recommendation 2: There should be consultation and communication of the prenatal findings with physicians looking after the patients postnatally.
Recommendation 3: There should be threshold values for the diagnosis of UT dilation based on sonographic imaging and stratified based on gestational age at presentation (also listed in a table in the paper).
Recommendation 4: There is a proposed follow-up management scheme – also listed in the paper.
Recommendation 5: Stratification of risk should be based on the grading of UT in the most severely affected side in cases of bilateral dilation.
Recommendation 6: Reporting UT dilation should follow seven imaging parameters – also listed in the paper as a table.

The consensus felt that conversion from existing classifications such as the SFU system would be relatively easy as the UT dilation classification system incorporates three broad categories of sonographic findings: degree of UT dilation, parenchymal quality, and associated anomalies. It is clear that any consensus statement is only valuable if all adopt it, and that remains to be seen. 

Multidisciplinary consensus on the classification of prenatal and postnatal urinary tract dilation ( UTD classification system).
Nguyen HT, Benson C, Bromely B, et al.
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Henrik Steinbrecher

Southampton University Hospital NHS Trust

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