[Reproducibility of the fetal nasal bone measurement by means of bidimensional and three-dimensional ecography during the second trimester of the pregnancy].

Aims: The utility of the valuation-measurement of the nasal bone in the prognosis of chromosomopaties during the second trimester of the pregnancy is demonstrated.

Objective: To evaluate the repeatability of nasal bone measurement during second trimester with bidimensional and three-dimensional sonography.

Material And Method: Nasal bone was measured in 50 single pregnancies. First observer carried out two measures of nasal bone with bidimensional sonography, and 1 measure with three-dimensional sonography. Second observer carried out just one measure with bidimensional sonography (2D) and just another one with three-dimensional sonography (3D). We studied the intraobserver variability with 2D sonography, and the interobserver variability with 2D and 3D sonography.

Results: 2D-sonography: nasal bone measurement showed excellent intraobserver correlation with a correlation coefficient of 0,87 (CI 95%: 0,78-0,93) and a little means difference of 0,18 (SD: 0,74). Indeed, there was a good interobserver correlation with a correlation coefficient of 0,92 (CI 95%: 0,85-0,95), and a means difference of 0,14 (SD: 0,56). 3D-sonography: there was a acceptable interobserver correlation with correlation coefficient of 0,70 (CI 95%: 0,52-0,82).

Conclusion: Nasal bone measurement is highly reproducible by means of bidimensional sonography while using three-dimensional sonography, the results are just acceptable.