Quantified discordant placental echogenicity in twin anemia-polycythemia sequence (TAPS) and middle cerebral artery peak systolic velocity

OBJECTIVE: To quantify sonographic placental echogenicity in twin anemia-polycythemia sequence (TAPS) and to correlate it with middle cerebral artery peak systolic velocity (MCA-PSV) measurements.

METHODS: We performed a retrospective search for consecutive TAPS cases between 16 and 36 weeks of gestation (MCA-PSV > 1.5 multiples of the median (MoM) in the anemic donor and < 1.0 MoM in the polycythemic recipient) in our database of monochorionic twin gestations from January 2007 until December 2016. In cases for which ultrasound images showing the donor's and the recipient's part of the placenta were available, echogenicity for both twins was quantified by image processing. MCA-PSV Doppler values of both fetuses were correlated to their respective placental echogenicity. Placental thickness of both twins was also measured.

RESULTS: Of 756 cases with MCA-PSV measurements identified from the database, 36 (4.8%) had TAPS; of these, 23 had TAPS combined with twin-twin transfusion syndrome and 13 showed isolated TAPS. Placental echogenicity could be quantified in 28 pregnancies. Mean ± SD placental echogenicity of donor twins was significantly higher than that of recipients (138.7 ± 22.8 vs 77.9 ± 37.0; P < 0.0001). Furthermore, a significant positive correlation was found between placental echogenicity and MCA-PSV MoM (R = 0.67, P < 0.0001). Mean placental thickness of donor twins (n = 20) was significantly higher than that of recipients (49.3 mm ± 13.4 vs 25.4 mm ± 10.1; P < 0.0001).

CONCLUSIONS: Echogenicity of the placental share in recipient and donor twins with TAPS correlates with MCA-PSV values. Quantification of sonographic placental echogenicity may help to determine the severity of TAPS in monochorionic twins. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.