Hertzberg B S, Kliewer M A, Freed K S, McNally P J, DeLong D M, Bowie J D, Kay H H
Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA.
Radiology. 1997 Jun;203(3):641-4. doi: 10.1148/radiology.203.3.9169682.
To define the size and appearance of the normal fetal third ventricle.
The third ventricle was prospectively assessed in 441 consecutive normal second- and third-trimester fetuses. The fetuses were divided into six gestational age ranges. Data regarding the size and configuration of the third ventricle were analyzed for each group.
The third ventricle was seen in 435 of 440 (98.9%) fetuses. It appeared as a single echogenic line between the thalami in 171 (38.9%) fetuses, as parallel echogenic lines outlining a fluid-filled lumen in 243 (55.2%) fetuses, and as divergent lines delineating a V-shaped fluid-filled structure in 21 (4.8%) fetuses. The single-line configuration was most common early in the second trimester. Later in pregnancy, the ventricle walls could be discerned as separate parallel or divergent lines outlining a fluid-filled lumen. The average width of the ventricle was relatively constant at approximately 1 mm from 12 to 28 weeks. After this time, it enlarged, reaching a maximum 1.9 mm.
The third ventricle can be imaged in most second- and third-trimester fetuses. Its size and configuration evolve through the second and third trimesters. This evolution must be considered in the evaluation of normality. At any gestational age, a third ventricle greater than 3.5 mm in width should be viewed with concern for abnormality.
明确正常胎儿第三脑室的大小和形态。
前瞻性评估441例连续的孕中期和孕晚期正常胎儿的第三脑室。将胎儿分为六个孕周范围。分析每组关于第三脑室大小和形态的数据。
440例胎儿中有435例（98.9%）可见第三脑室。在171例（38.9%）胎儿中，第三脑室表现为丘脑之间的单一强回声线；在243例（55.2%）胎儿中，表现为勾勒出充满液体腔隙的平行强回声线；在21例（4.8%）胎儿中，表现为勾勒出V形充满液体结构的发散线。单线形态在孕中期早期最为常见。在妊娠后期，脑室壁可被识别为勾勒出充满液体腔隙的单独平行或发散线。从12周到28周，脑室平均宽度相对恒定，约为1mm。此后，脑室增大，最大达到1.9mm。
大多数孕中期和孕晚期胎儿的第三脑室均可成像。其大小和形态在孕中期和孕晚期会发生变化。在评估是否正常时必须考虑这种变化。在任何孕周，宽度大于3.5mm的第三脑室应被视为异常而予以关注。
