Assistant Professor of Radiology, Tabriz University of Medical Sciences
Umbilical artery doppler indices are commonly assessed during the second and third trimester ultrasound exams. As these are commonly investigated and reported in only one side, we compared doppler indices between right and left umblical arteries in normal fetuses to find if they are significantly different.
This analytical single-center study was conducted on 326 healthy fetuses of healthy mothers in second or third trimester, implementing a 3-5 Mhz curved probe, assessing doppler indices (namely RI and PI) in right and left umbilical arteries. Mechanical and thermal indices were kept below recommended values to ensure fetus safety. In all case, umblical arteries were assessed in transvrse plane as they pass by the urinary bladder wall in pelvis.
The mean value of RI was measured at a range of 0.30 to 1.20 for left umbilical artery, and 0.10 to 1.70 for right umbilical artery. The PI range for left and right umbilical arteries were 0.10 to 2.20, and 0.09 to 2.24, respectively. In general, the RI of the left umbilical artery was higher than, equal to, and lower than right umblical artery in 139, 22, and 165 cases, respectively (P = 0.013). The PI of the left umbilical artery was higher than, equal to, and lower than right umblical artery in 153, 23, and 150 cases, respectively (P= 0.662). These findings show that RI differs significantly between right and left umblical arteries, but PI does not. Nonetheless, RI could be higher in left or right umblical artery with a relatively equal frequency.
According to the findings of the present study, the mean RI of the umbilical arteries is better to be reported for both sides as the higher RI may changes the management strategy.