Doppler ultrasound of twin transfusion syndrome

Doppler sonography of umbilical arteries was used to evaluate eight cases of twin transfusion syndrome (TTS). Data were collected regarding the Doppler and real-time sonographic evaluation, clinical course, and outcome. In addition, the literature was reviewed. An abnormal peak systolic velocity (A) to end diastolic velocity (B) ratio, as defined by Giles et al, was seen in at least one twin in five cases. A difference in the A/B ratios between the two twins was greater than 0.4 in all eight cases. Doppler studies were able to suggest which fetus was encountering greater placental resistance, however they could not differentiate donor from recipient or provide prognostic data regarding outcome. Doppler evaluation was helpful when there was uncertainty as to whether growth discrepancy in a twin pregnancy was significant enough to suggest a pathologic state. In the future, Doppler sonography may be helpful in evaluating the effectiveness of therapy in TTS. Variable Doppler findings confirm that TTS is an extremely complex dynamic physiologic state.