Visualisation of the vascular equator in twin-to-twin transfusion syndrome by virtual fetoscopy

Background: Twin-to-twin transfusion syndrome (TTTS) is a serious complication of monochorionic twin gestation, which has a high risk of perinatal morbidity and mortality. Fetoscopic laser photocoagulation of the vascular anastomoses is the preferred treatment. Nowadays, Solomon technique which consists the vascular coagulation of all anastomoses in the placental equator is the preferable method.

Objective: To develop a method of virtual fetoscopy by means of ultrasound and resonance magnetic imaging (MRI) scan data to allow the identification of placental equator.

Results: MRI was performed in a twin monochorionic twin pregnancy with 28 weeks previously treated for TTTS with fetoscopic laser photocoagulation. A three-dimensional (3D) file of the placenta was created from overlapping image layers generated by MRI using Mimics software. Virtual fetoscopy allowed adequate visualization of fetuses, umbilical cord insertion and placental equator.

Conclusion: Virtual fetoscopy is a non-invasive technique which allowed adequate identification of placental equator, and it may be an important learning method to novice fetal endoscopic surgeons in TTTS cases.