Is 3D technique superior to 2D in Down syndrome screening? Evaluation of six second and third trimester fetal profile markers

Objective: The objective of this article is to investigate whether in the clinical setting of second trimester ultrasound (US) investigations, 3D multiplanar correction prior to the measurement of Down syndrome (DS) facial markers (nasal bone length, prenasal thickness, fetal profile line, maxilla-nasion-mandible angle, prenasal thickness to nasal bone length ratio, and prefrontal space ratio) is superior to subjective judgment of a correct midsagittal plane by 2D technique. Methods: Measurements were performed on 2D images and 3D volumes (corrected to the midsagittal plane), acquired during the same scanning session. Results: All six markers were measured in 105 datasets (75 of euploid fetuses and 30 of DS fetuses). The maxilla-nasion-mandible angle measured on 2D images was significantly larger than on 3D volumes (p