Volume-corrected renal artery pulsatility index in normal fetuses during the second and third trimester of gestation / 中华超声影像学杂志

ABSTRACT

Objective:To measure the normal single fetal volume-corrected renal artery pulsatility index (vcRAPI) in the middle and late pregnancy, and to determine the normal reference range of vcRAPI and to observe its correlation with gestational age.Methods:The sagittal and transverse sections of the kidneys of normal single pregnant fetuses at 22 to 36 gestational weeks in the Second Xiangya Hospital from January to July 2019 were prospectively obtained by two-dimensional ultrasound. Estimated renal volume was calculated as length× transverse × antero-posterior×π/6. Pulse Doppler was used to detect the renal artery pulsatility index (RAPI) at the renal hilum in coronary section. The vcRAPI was obtained by dividing the RAPI by the ipsilateral estimated renal volume. The normal reference range of vcRAPI was established, and the scatter diagram of its relationship with gestational age was drawn. Multiple regression models were fitted to select the best fitting curve and to obtain the relevant formulas.Results:A total of 540 normal fetuses were enrolled and the normal reference value range of vcRAPI was established. The vcRAPI of both kidneys was negatively correlated with gestational age ( r=-0.793, -0.780; all P<0.001). The left kidney parameters and gestational age were best fitted with S-curve, and the right kidney parameters were best fitted with power curve. There was no difference between the right and left kidney vcRAPI values( P>0.05). Conclusions:The vcRAPI of normal fetuses decreases with gestational age, indicating that renal perfusion increases with gestational age. In this study, normal reference range of vcRAPI is established to provide reference basis for prediction and monitoring of complicated pregnancy.