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Updated: Oct 3, 2025

Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation
Published on: January 7, 2021
Fetal renal artery blood flow - Normal ranges
Sonja Brennan1,1, David Watson2,2, Michal Schneider3
1Ultrasound Department, Townsville University Hospital, Douglas, Townsville, Australia.
New standard charts for fetal renal artery blood flow, including resistive index (RI) and pulsatility index (PI), were developed. These charts help identify normal ranges and variations during pregnancy.
Area of Science:
- Obstetrics and Gynecology
- Fetal Medicine
- Medical Imaging
Background:
- Fetal renal artery blood flow assessment is crucial for monitoring fetal well-being.
- Establishing normal reference ranges is essential for accurate interpretation of Doppler ultrasound findings.
- Previous studies lacked comprehensive charts for fetal renal artery blood flow parameters.
Purpose of the Study:
- To develop standard charts for fetal renal artery blood flow parameters.
- To define normal ranges for fetal renal artery resistive index (RI) and pulsatility index (PI) throughout pregnancy.
- To evaluate the intra- and interobserver reliability of these fetal blood flow measurements.
Main Methods:
- Prospective, longitudinal study of 72 low-risk singleton pregnancies.
- Serial ultrasound examinations using pulse wave Doppler to measure fetal renal artery RI and PI.
- Mixed effects modeling used to create standard charts; reliability analyzed using intraclass correlation coefficient.
Main Results:
- Standard charts for fetal renal artery RI and PI were created, including various centiles.
- Acceptable intraobserver reliability was found for both RI (0.66) and PI (0.88).
- Poor interobserver reliability was noted for RI (0.11) and PI (-0.56).
Conclusions:
- Novel charts illustrate fetal renal artery blood flow changes during gestation.
- These charts can aid in detecting deviations from normal ranges in clinical practice.
- The charts may be valuable for future studies on fetal kidney function projection.
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