Three-dimensional multiplanar ultrasound is a valuable tool in the study of the fetal profile in the second trimester of pregnancy.

OBJECTIVES

To evaluate the additional value of three-dimensional (3D) multiplanar ultrasound in the examination of the fetal profile.

METHODS

Two 3D volumes of the fetal head were obtained from 84 fetuses at 22 to 29 weeks' gestation. The volumes were taken starting at the midsagittal plane with the fetus facing the transducer. The success rate and acquisition time to obtain each volume and display the exact midsagittal plane by 3D multiplanar ultrasound were analyzed. The correction angles from the original two-dimensional (2D) profile view to the exact midsagittal plane were noted. Of six measurements, related to the fetal nose and jaws, the success rate and the intraobserver reproducibility between the 2D and the 3D multiplanar ultrasound were compared.

RESULTS

In 81 (96.4%) cases we succeeded in obtaining a profile volume, 70% of the volumes being obtained within 10 min. It was possible to define by multiplanar mode the exact midsagittal plane in less than 1 min. The mean rotation necessary to obtain the exact midsagittal plane with 3D multiplanar mode was significantly larger around the y-axis (11.9 degrees ) than around the z-axis (4.3 degrees ) of the fetus. For between 5 and 12% of the six measurements under investigation it was not possible to obtain values with 2D ultrasound. However, 3D ultrasound made these measurements possible in at least one volume. The intraobserver reproducibility was higher with 3D multiplanar ultrasound than with 2D ultrasound, this difference being statistically significant for five of the six measurements.

CONCLUSIONS

3D multiplanar ultrasound improves the topographic depiction of the midsagittal profile view, enables correct measurement of anatomical details and improves intraobserver reproducibility. 3D multiplanar ultrasound is a powerful instrument for investigating the fetal profile.