4. Up-to-date fetal neuroimaging

Ritsuko K. Pooh
CRIFM Clinical Research Institute of Fetal Medicine PMC

Abstract
　　Imaging technologies have been markedly improved recently and contribute to the prenatal evaluation of the fetal central nervous system (CNS) development and assessment of CNS abnormalities in utero. Introduction of high-frequency transvaginal transducers has contributed to establishing “sonoembryology” and the recent general use of transvaginal sonography in early pregnancy has facilitated the early diagnoses of major fetal anomalies. Combination of transvaginal approach and three-dimensional (3D) ultrasound has established‘3D sonoembryology’, producing more objective and accurate information on early embryonal and the fetal development and the natural history of fetal abnormalities. In middle and late pregnancy, fetal CNS is generally evaluated through the maternal abdominal wall. The brain, however, is a three-dimensional structure, and should be assessed in basic three planes of sagittal, coronal and axial sections. Sonographic assessment of the fetal brain in the sagittal and coronal sections, requires an approach from the fetal parietal direction. Transvaginal sonography of the fetal brain has opened up a new field in medicine, “neurosonography”. Transvaginal observation of the fetal brain offers sagittal and coronal views of the brain from the fetal parietal direction through the fontanelles and/or the sagittal suture as ultrasound windows. This method has contributed to the prenatal assessment of congenital CNS anomalies and acquired brain damage in utero.

Keywords： Fetus, Central nervous system, Three-dimensional ultrasound