Four-dimensional ultrasonographic guidance for invasive obstetric procedures

This pilot study evaluated the use of 4-dimensional (4D) real-time ultrasonographic needle guidance for amniocentesis, chorionic villus sampling (CVS), cordocentesis, and intrauterine transfusions.

Ninety-nine consecutive procedures were performed with 4D (real-time) multiplanar ultrasonographic imaging. Amniocentesis was done freehand in 3 orthogonal planes of view. Chorionic villus sampling, cordocentesis, and intrauterine transfusions were accomplished with a needle guide and 2 projected orthogonal planes.

Needle tip visualization in the A, B, and C orthogonal planes during amniocentesis was noted in 93%, 63%, and 69% of cases, respectively. When a needle guide was used during CVS and cordocentesis, the needle tip was always seen in the 2 projected orthogonal planes, and no lateralization occurred. Four intrauterine transfusions were done with the 4D technique. The only procedural complication in any patient was bradycardia from vessel spasm during an intrauterine transfusion, requiring a cesarean delivery. There were no statistical differences (P > .05) between the numbers of needle insertions required in the 4D group compared with a historical control group in which 2-dimensional ultrasonographic needle guidance was used.

In this feasibility study, a real-time 4D needle guidance technique was successfully used to perform amniocentesis, CVS, cordocentesis, and intrauterine transfusion. This appeared to contribute to the accuracy of needle placement by eliminating the lateralization phenomenon when a fixed needle guide attachment was used (for CVS and cordocentesis). Needle tip visualization was seen in each orthogonal plane in most freehand 4D amniocentesis cases. Future developments in 4D ultrasonographic technology may refine the utility of this technique for invasive obstetric procedures.