Ultrasound Measurement Of Fetal Kidney And The Value In Predicting The Prognosis Of Fetal Hydronephrosis

Part1. Ultrasound measurement of volume and blood flow in normal fetal kidneyObjective:To measure the volume and blood flow parameters of normal fetal kidney and to establish the normal ranges of various parameters during various gestational ages.Methods:A total of357women with16weeks～41weeks of normal gestation were enrolled in the study who received routine obstetric ultrasound in our hospital from September2008to March2013. The volume and blood flow parameters of kidney and fetal growth parameters were measured by two and three dimensional ultrasound. The relations between various parameters of kidney with gestational age, growth indexes were analysed. Results:1、Renal volume was linearly associated with gestational age, and renal volume=-7.01+0.554x gestational age (16weeks≤gestational age≤41weeks).2、Fetal volume was significantly related to growth indexes, and the correlation with height, weight before pregnancy was not obvious.3、PSV, EDV and TAMXV of renal artery increased with gestational age; S/D, PI and RI decreased with gestational age.Conclusions:1、The volume of normal fetal kidney increases gradually along with the gestational age, a linear correlation is between them.2、The size of normal fetal kidney is associated with fetal growth itself, but is not affected by maternal height, weight before pregnancy.3、With the increase of gestational age, the blood flow of fetal renal artery speeds, resistance drops and blood flow perfusion increases. Part2. The value of ultrasound in predicting the prognosis of fetal hydronephrosisAbstractObjective:To apply various ultrasound indexes to evaluate the degree of hydronephrosis, and analyze the relations between indexes with fetal outcome, provide the basis for prenatal intervention and treatment after birth.Methods:A total of256pregnant women with fetal hydronephrosis were enrolled in the study from January2008to October2012, and≥28weeks of gestation and≥10mm for renal pelvis anteroposterior diameter (APD) were required. A new three-dimensional ultrasound index of renal parenchyma volume/kidney volume was compared with the commonly used ultrasound indexes including APD, sides, renal parenchyma thickness, grade of Society of Fetal Urology (SFU) hydronephrosis scale and hydronephrosis index, according to the effectiveness to predict fetal outcome judged by need for postnatal surgery. And the changes of renal parameters, umbilical artery blood flow parameters and fetal growth parameters in fetal hydronephrosis were observed.Results:1、The sides, thickness of renal parenchyma, APD, SFU grading, HI and renal parenchyma volume/kidney volume can predict the need for surgery after birth for fetal hydronephrosis. Bilateral hydronephrosis; the lower renal parenchyma thickness, HI, renal parenchyma volume/kidney volume were; the higher APD and SFU grading were; the greater was the risk of surgery. The combination of sides, APD and renal parenchyma volume/kidney volume was the most efficient index to predict the need for surgery. Among all the single indexes, renal parenchyma volume/kidney volume was the best predictor.2、APD1.35cm, renal parenchyma thickness0.5cm, SFU level2, HI0.69and renal parenchyma volume/kidney volume0.81were the cut-off values to predict the need for surgery after birth for fetal hydronephrosis.3、Introducing sides, APD and renal parenchyma volume/kidney volume to the model of predicting whether the fetus need surgery after birth, an equation was established:((unilateral hydronephrosis=0, bilateral hydronephrosis=1)P≥0.255was positive (need surgery), and P＜0.255for negative (no surgery).4、The sides, APD, SFU grading and renal parenchyma volume/kidney volume were related to the time needed for spontaneous regression after birth for fetal hydronephrosis.5、The volumes of the affected and contralateral kidneys in fetal hydronephrosis increased. VI, VFI decreased; FI, PSV increased.The blood flow parameters of umbilical artery in fetal hydronephrosis had no obvious change. 6、The fetal growth parameters in fetal hydronephrosis had no obvious change.Conclusions:1、Ultrasound examination is valuable to predict whether the fetus with hydronephrosis need surgery after birth, among the indexes, the efficiency of three-dimensional ultrasound index of renal parenchyma volume/kidney volume is highest.2、The majority of fetal hydronephrosis naturally fades after birth, and the fading time is closely related to the ultrasonic indexes.3、Fetal hydronephrosis does not affect fetal blood flow perfusion and growth development, and the fetus is generally not recommended for induced labor.