3-DIMENSIONAL IMAGING OF THE BRAIN CAVITIES IN HUMAN EMBRYOS

A system for high-resolution three-dimensional imaging of small struct ures has been developed, based on the Vingmed CFM-800 annular array, s ector scanner with a 7.5-MHz transducer attached to a PC-based TomTec Echo-Scan unit. A stepper motor rotates the transducer 180 degrees and the complete three-dimensional scan consists of 132 two-dimensional i mages, video-grabbed and scan-converted in to a regular volumetric dat a set by the TomTec unit. Three normal pregnancies with embryos of ges tational age 7, 9 and 10 weeks received a transvaginal examination wit h special attention to the embryonic/fetal brain. In all three cases, it was possible to obtain high-resolution images of the brain cavities . At 7 weeks, both hemispheres and their connection to the third ventr icle were delineated. The isthmus rhombencephali could be visualized. At 9 weeks, the continuous development of the brain cavities could be followed and at 11 weeks the dominating size of the hemispheres could be depicted It is concluded that present ultrasound technology has rea ched a stage where structures of only a few millimeters can be imaged in vivo in three-dimensions with a quality, that resembles the plaster figures used in embryonic laboratories The method can become an impor tant tool in future embryological research and also in the detection o f early developmental disorders of the embryo.