An introduction to fetal neurosonography using three-dimensional ultrasound

Multiplanar mode: nomenclature The multiplanar mode is probably the most useful tool for assessment of the fetal central nervous system (CNS). With this mode of display, the plane parallel to the acquisition plane or “start” appears in the upper left corner of the screen and is identified with the letter A. The plane perpendicular to A, but parallel to the ultrasound beam, is identified with the letter B and appears in the upper right corner. The plane that is both perpendicular to the “start” scan and the ultrasound beam is defined as C (Figure1). Transabdominal 2D ultrasound based on axial planes has, so far, been the standard approach for the imaging of fetal central nervous system abnormalities. In recent years three-dimensional ultrasound has shown to be a potentially useful tool both in basic and detailed examination of the fetal brain. The aim of this paper is to describe the possible applications of this technique.