Hydronephrosis and Pyelectasis in Children: SFU Classification, AP Pelvic Measurement, and Observation Strategy
Measurement of Anteroposterior Pelvic Diameter (APD)
The key quantitative parameter in assessing the dilation of the collecting system in children is the anteroposterior diameter of the renal pelvis (AP renal pelvic diameter). It is recommended to perform this measurement with the patient in the prone position [Hagen-Ansert, 2023]. Specific numerical thresholds for APD are not provided in the source fragments [to be clarified].
SFU Classification and UTD System
For postnatal assessment, the SFU classification and the Urinary Tract Dilation (UTD) classification system are used. According to a small survey conducted through SFU, approximately 70% of pediatric urologists continued to use the SFU grading system, while 19% switched to the UTD system [Hagen-Ansert, 2023].
Additional Assessment Parameters
In postnatal assessment, in addition to the APD of the pelvis, the following features are considered [Hagen-Ansert, 2023]:
| Parameter | Comment |
|---|---|
| Involvement of calyces (dilation) | The distinction between central and peripheral calyces is made only postnatally |
| Thickness of renal parenchyma | Assessment of thinning |
| Appearance of renal parenchyma | Changes in echotexture |
| Bladder anomalies | — |
| Ureteral anomalies | — |
Role of Doppler Ultrasound
In unilateral hydronephrosis in children and adolescents, the Doppler resistance index (RI) and the ratio of resistance indices were studied [Brkljacic et al., 2002]. Color Doppler study of ureteric jets was also used to assess hydronephrosis [deBesse et al., 2008]. Specific reference values for RI are not indicated in the fragments [to be clarified].
Frequently asked questions
In what position should the APD of the pelvis be measured?
It is recommended to measure the anteroposterior diameter of the pelvis with the patient in the prone position [Hagen-Ansert, 2023].
Which classification is more commonly used — SFU or UTD?
According to an SFU survey, about 70% of pediatric urologists continued to use the SFU system, while 19% switched to the UTD system [Hagen-Ansert, 2023].
Can central and peripheral calyces be distinguished prenatally?
No, the distinction between central and peripheral calyces is made only postnatally [Hagen-Ansert, 2023].
What Doppler parameters were used in unilateral hydronephrosis in children?
The Doppler resistance index (RI) and the ratio of resistance indices were studied in unilateral hydronephrosis in children and adolescents [Brkljacic et al., 2002].
What specific threshold values for APD are indicated in the source?
Specific numerical thresholds for the APD of the pelvis are not provided in the source fragments [to be clarified].