MoDi Twin Placental Imaging

Study Summary

Twin-twin transfusion syndrome (TTTS) can arise in monochorionic, diamniotic (MoDi), those identical twins arising from division of a single fertilized ovum at 4-8 days gestational age (GA) or monochorionic, monoamniotic (MoMo or Mono-Mono) twins, arising from division on day 8-13 GA. In monochorionic twin pregnancies sharing a single placenta often unevenly, anastomoses \[connections\] artery to artery (AA), vein to vein (VV), and artery to vein (AV) can occur. AV anastomoses usually flow unilaterally, shunting blood unevenly towards one twin and away from the other. This can lead to fluid overload and polyhydramnios along with many other pathologies in one twin while the other twin suffers from inadequate blood flow and oligohydramnios, along with secondary pathologies arising from these conditions. TTTS will affect approximately 8-10% of MoDi twins while 6% of MoMo twins will suffer with this condition. Treatment for TTTS is necessary, with the donor or 'pump' twin having around an 80% chance of death without medical intervention. The aim of this single arm, unblinded, feasibility study of the Verasonics Vantage 256 device is to leverage the devices ultrafast power Doppler imaging (uPDI) to perform microvascular mapping of the placenta in healthy, non-anomalous, 18-26 week gestational age (GA), monochorionic, diamniotic (MoDi) or monochorionic, monoamniotic (MoMo/MonoMono) pregnancies without TTTS, twin reversed arterial perfusion sequence (TRAP), or maternal vascular disease. Participants will be recruited in the Maternal Fetal Medicine department of Carilion Clinic, which specializes in high risk or complicated pregnancies. Pregnant subjects carrying monochorionic twins and scheduled for appointments at the clinic, who meet study eligibility criteria, will be approached between weeks 18 and 26 for study enrollment. Those providing informed consent will undergo a single, transabdominal ultrasound examination by a licensed ultrasonographer or obstetrician

Primary Outcome

Obtain 10 subjects' ultrafast power Doppler imaging (uPDI) with the Verasonics Vantage 256 research ultrasound machine that successfully visualize the placenta's microvasculature. The ability to appreciate the placental microvasculature will be determined \[Y/N\] by perinatologists working as investigators on the study.

Interventions

• DEVICE Verasonics Vantage 256 Ultrasound