Brainstem-vermis and brainstem-tentorium angles allow accurate categorization of fetal upward rotation of cerebellar vermis.

Abstract

OBJECTIVE:

To evaluate the role of the brainstem-vermis (BV) and brainstem-tentorium (BT) angles in the differential diagnosis of upward rotation of the fetal cerebellar vermis.

METHODS:

The BV and BT angles were measured retrospectively on median sonographic views of the brain in 31 fetuses at 19-28 weeks' gestation with upward rotation of the cerebellar vermis due to Blake's pouch cyst (n = 12), Dandy-Walker malformation (n = 12) and cerebellar vermian hypoplasia (n = 7). Eighty normal fetuses at 20-24 weeks were included as controls.

RESULTS:

In the control group, BV and BT angles were 9.1 ± 3.5° (range, 4-17°) and 29.3 ± 5.8° (range, 21-44°), respectively. The BV angle was significantly increased in each of the three subgroups of anomalies: Blake's pouch cyst (23 ± 2.8°; range, 19-26°), vermian hypoplasia (34.9 ± 5.4°; range, 24-40°) and Dandy-Walker malformation (63.5 ± 17.6°; range, 45-112°), the angle increasing with increasing severity of the condition. The BT angle had a similar pattern but there was overlap among the different groups.

CONCLUSION:

The BV angle and, to a lesser degree, the BT angle are simple and reproducible measurements that provide valuable additional information for the categorization of upward rotation of the fetal cerebellar vermis. From mid gestation, a BV angle > 45° is strongly suggestive of a Dandy-Walker malformation, while a measurement < 30° favors the diagnosis of a Blake's pouch cyst.

• Authors: P Volpe, E Contro, F De Musso, T Ghi, A Farina, A Tempesta, G Volpe, N Rizzo, G Pilu
• Journal: Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology (Ultrasound Obstet Gynecol) Vol. 39 Issue 6 Pg. 632-5 (Jun 2012) ISSN: 1469-0705 [Electronic] England
• PMID: 22253138 (Publication Type: Evaluation Study, Journal Article, Multicenter Study)
• Copyright: Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

Topics

• Arachnoid Cysts (diagnostic imaging, embryology)
• Brain Stem (abnormalities, diagnostic imaging, embryology)
• Cerebellum (abnormalities, diagnostic imaging, embryology)
• Cranial Fossa, Posterior (abnormalities, diagnostic imaging, embryology)
• Dandy-Walker Syndrome (diagnostic imaging, embryology)
• Diagnosis, Differential
• Female
• Gestational Age
• Humans
• Pregnancy
• Reproducibility of Results
• Ultrasonography, Prenatal (methods)