Monteagudo Ana, Timor-Tritsch Ilan E
Division of Obstetrical and Gynecological Ultrasound, Department of Obstetrics and Gynecology, Professor of Obstetrics and Gynecology, NYU School of Medicine, 530 First Avenue NB9N26, New York, NY 10016, USA.
Prenat Diagn. 2009 Apr;29(4):326-39. doi: 10.1002/pd.2146.
The developmental changes of the fetal central nervous system (CNS) during the second and third trimesters, specifically the brain, relate mostly to changes in size. However, other changes do occur in the fetal brain during the second and third trimester such as: the union of the cerebellar hemispheres, development of the corpus callosum (CC), and increasing complexity of the cerebral cortex. These changes follow a well-defined developmental timeline recognizable by sonography. The fetal neuroscan can be divided into a 'basic scan' which is performed transabdominally and a 'targeted Exam or neurosonogram' which uses a multiplanar approach, which preferably should be performed transvaginally. During the 'basic scan', several brain structures are imaged in addition to obtaining important biometric measurements. The 'neurosonogram' is a more extensive or detailed fetal study during which the emphasis is on the addition of coronal and sagittal planes. The easiest way to obtain these planes, if the fetus is in a cephalic presentation, is the transvaginal route. Three-dimensional (3D) sonography should, if possible, be performed transvaginally using the multiplanar approach. An added benefit of 3D sonography is the ability to display and render the volume in a variety of ways which may enhance the detection of pathology.
妊娠中期和晚期胎儿中枢神经系统（CNS）的发育变化，特别是大脑的变化，主要与大小变化有关。然而，在妊娠中期和晚期，胎儿大脑也会发生其他变化，如：小脑半球融合、胼胝体（CC）发育以及大脑皮层复杂性增加。这些变化遵循超声可识别的明确发育时间线。胎儿神经扫描可分为经腹部进行的“基础扫描”和采用多平面方法的“靶向检查或神经超声检查”，后者最好经阴道进行。在“基础扫描”期间，除了获取重要的生物测量数据外，还对几个脑结构进行成像。“神经超声检查”是一项更广泛或更详细的胎儿检查，重点是增加冠状面和矢状面。如果胎儿是头先露，获得这些平面的最简单方法是经阴道途径。如果可能，三维（3D）超声检查应采用多平面方法经阴道进行。3D超声检查的另一个好处是能够以多种方式显示和呈现容积，这可能会提高病变的检测率。
