Freehand three-dimensional Doppler demonstration of monochorionic vascularanastomoses in vivo: a preliminary report

Objectives To demonstrate the three-dimensional vascular anatomy of monocho rionic placental anastomoses in vivo, both arterioarterial and arteriovenou s. Design Two-dimensional placental mapping techniques were used to locate art erioarterial and arteriovenous anastomoses. A freehand sweep was performed across the anastomotic site, and multiple images were stored to disk, at 17 Hz. These were then segmented to show only, color information (vascular fl ow) using purpose-designed software (CQ analysis) and the files reconstruct ed into a three-dimensional volume, for multidirectional viewing and movie generation. Results Both arterioarterial and arteriovenous anastomoses could be visuali zed in detail. Reconstruction of a dual volume of gray-scale and segmented color images allowed recreation of the vascular anatomy within the placenta l substance, as well as retention of the original directional flow informat ion. Conclusions Detailed anastomotic anatomy can be demonstrated three dimensio nally in vivo. Given the increasing evidence implicating various anastomoti c configurations in pathological intertwin transfusion, this technique may, prove useful in the antenatal assessment and treatment of monochorionic tw in pregnancies.