The cavum septi pellucidi in euploid and aneuploid fetuses.

Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology

PubMedID: 23303556

Abele H, Babiy-Pachomow O, Sonek J, Hoopmann M, Schaelike M, Kagan KO. The cavum septi pellucidi in euploid and aneuploid fetuses. Ultrasound Obstet Gynecol. 2013;42(2):156-60.
OBJECTIVE
To examine whether the cavum septi pellucidi (CSP) is larger in second- and third-trimester fetuses with chromosomal abnormalities than in euploid fetuses.

METHODS
This was a retrospective study utilizing stored two-dimensional images of second- and third-trimester fetuses between 18 and 40 weeks' gestation from three centers in Germany. The width of the CSP was measured by placing the calipers on the inner portion of its lateral borders. Two operators, both of whom were blinded to the fetal karyotype and to the measurements obtained by the other, measured the CSP width. The normal range in euploid fetuses was computed based on the biparietal diameter (BPD) by applying univariate regression analysis. The CSP width in euploid and aneuploid fetuses was transformed into Z-scores and compared using Student's t-test. Univariate regression analysis was used to determine the dependency of Z-score on head biometry.

RESULTS
The study population consisted of 406 singleton pregnancies, 267 with euploid fetuses, 81 with trisomy 21, 50 with trisomy 18 and eight with trisomy 13. In the euploid group, the mean CSP width was 4.5 (range, 1.8-7.4)?mm. Regression analysis showed a significant dependency of CSP width on BPD (CSP width?=?0.658?+?(0.064?×?BPD), r?=?0.781, P?
CONCLUSION
A large CSP width should prompt a detailed ultrasound examination to further assess the risk for chromosomal abnormalities. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.