Comparison of the Diagnostic Accuracy of Doppler Cerebroplacental Ratio Versus Standard Fetal Biometry for Fetal Growth Restriction

Abstract

Objective: To assess the diagnostic accuracy of the Doppler Cerebroplacental ratio for fetal growth restriction keeping fetal biometry as the reference standard.

Study Design: Cross-sectional study.

Place and Duration of Study: Department of Radiology, Combined Military Hospital, Multan Pakistan, from May to Oct 2020.

Methodology: Two hundred and fifty-six-singleton pregnancies ≥ 30 weeks were included and underwent fetal biometry, including estimated fetal weight (EFW) by trans-abdominal ultrasound. The umbilical artery and middle cerebral artery resistive indices were evaluated using Doppler ultrasound, and Cerebroplacental ratio (CPR) was calculated. The presence or absence of fetal growth restriction (FGR) was noted using cut-off EFW of 10th centile and CPR of 1.0.

Results: Cerebroplacental ratio showed FGR in 145(56.64%) patients. Fetal biometry showed FGR in 141 (55.08%) patients,whereas 115(44.92%) patients revealed none. Of 145 CPR-positive patients, 127(87%) were true positive, while 18(12%) were false positive. Among 111 CPR-negative patients, 14(0.12%) were false negative, while 97(87%) were true negative. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of the Cerebroplacental ratio were 90.07%, 84.35%, 87.59%, 87.39% and 87.50%, respectively.

Conclusions: Doppler Cerebroplacental ratio is sensitive for diagnosing fetal growth restriction; however, its role as a stand alone test needs further evaluation and may be enhanced with other tools such as estimated fetal weight.