Third ventricle: size and appearance in normal fetuses through gestation.

Journal Article (Journal Article)

PURPOSE: To define the size and appearance of the normal fetal third ventricle. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Full Text

Duke Authors

Cited Authors

  • Hertzberg, BS; Kliewer, MA; Freed, KS; McNally, PJ; DeLong, DM; Bowie, JD; Kay, HH

Published Date

  • June 1997

Published In

Volume / Issue

  • 203 / 3

Start / End Page

  • 641 - 644

PubMed ID

  • 9169682

International Standard Serial Number (ISSN)

  • 0033-8419

Digital Object Identifier (DOI)

  • 10.1148/radiology.203.3.9169682


  • eng

Conference Location

  • United States