Sonographic assessment of fetal brain morphology

The changing appearance of the developing fetal brain during pregnancy is r emarkable and it is important for evaluating brain morphology accurately. T he intracranial structure is one of the organs which should be assessed thr ee-dimensionally. Therefore, the introduction of the transvaginal approach to the fetal brain by using the cranial fontanelles and sutures as ultrasou nd windows has improved fetal brain assessment. The combination of both tra nsabdominal and transvaginal approaches produces ultrasonic images of the i ntracranial structure in the median, oblique, coronal and axial sections. U sing the basic knowledge of the anatomical structure of the developing feta l brain and the different sonographic appearance at each gestational age of each section, congenital brain anomalies, acquired abnormalities in utero and variations of normality have been evaluated more accurately. It may be possible to differentiate between hydrocephalus and ventriculomegaly by obs ervation of the subarachnoid space. The study of the fetal brain using a tr ansvaginal gray-level histogram may have potential in the evaluation of fet a I periventricular changes related to postnatal brain damage. Recent remar kable developments in three-dimensional ultrasound and advances in magnetic resonance imaging technology may enable us to evaluate brain morphology mo re accurately. A functional evaluation of the intracranial condition and a prenatal prediction of neurological development may be the next task in thi s field.