Transvaginal 3D and Doppler ultrasonography of the fetal brain.

Transvaginal sonographic approach to the fetal brain, which provides detailed information about the fetal intracranial morphology, opened a new field in medicine, "neurosonography." The clinical significance of 3D ultrasound for prenatal diagnosis has been discussed since three-dimensional ultrasound was introduced in obstetrics. Three-dimensional ultrasound has several functions: surface reconstruction, multiplanar image analysis, three-dimensional sono-angiography, and volume calculation. In this article, we introduce transvaginal three-dimensional ultrasound for the assessment of fetal head and brain. Surface mode shows not only fetal head abnormality such as acrania but also normal cranial bones and sutures in the first trimester. Rotation of the brain volume image and multiplanar analysis enable tomographic visualization as magnetic resonance imaging. Sono-angiography shows the brain circulation three-dimensionally and extracted volume images of target organ provide information on detailed intracranial conditions. The technology is easy, noninvasive, and reproducible methods, and produces comprehensible and objective information.