Three-dimensional US of the fetus. Work in progress.

Purpose: To develop a system for three-dimensional (3D) ultrasonography (US) that readily interfaces with conventional equipment and to apply this system to fetal imaging.

Materials And Methods: An acquisition system based on transputer technology records from the video output of standard clinical scanners was interfaced with a position-sensing device, one component of which was attached to the US probe. The method differs from other 3D US methods as any conventional probe may be used, freehand scanning is possible, and no line-of-sight limitations operate. Such scanning was performed of 25 fetuses with gestation ages of 7-30 weeks.

Results: Acquisition typically took 3-5 seconds. Acquisition and reconstruction were successful in 17 of 25 cases and were easiest to perform in the first and second trimester. Surface rendering revealed anatomic detail that was not depicted with two-dimensional scanning.

Conclusion: The technique has the potential for recording complete anatomic studies for review and visualization of detail that is difficult to perceive on conventional US scans.