SIRENOMELIA SEQUENCE VERSUS RENAL AGENESIS - PRENATAL DIFFERENTIATIONWITH POWER DOPPLER ULTRASOUND

In order to assess the role of power Doppler ultrasound in the prenata l diagnosis of sirenomelia, prenatal findings in two fetuses with the sirenomelia sequence and in seven with bilateral renal agenesis were r eviewed and compared. Both conditions were characterized by absence of renal vessels. However, the two common iliac arteries were always vis ualized in fetuses with renal agenesis, whereas absence of distal bran ching of the main abdominal vessel was a characteristic feature of sir enomelia. Power Doppler ultrasound allows expeditious identification o f absent or non-functional renal arteries in fetuses with severe oligo hydramnios. In addition, incorporation of power Doppler imaging to ide ntify the aortic bifurcation could provide a diagnostic feature that c ould assist in the prenatal diagnosis of sirenomelia and in the differ ential diagnosis with other causes of bilateral renal agenesis.