Enlarged cavum septi pellucidi Z-scores in fetuses with trisomy 18.

We aim to establish a formula calculating the fetal cavum septi pellucidi (CSP) width Z-scores and compare CSP width between the normal fetus and 18-trisomy fetus. In this retrospective study, 608 normal fetuses and 71 fetuses with the 18-trisomy syndrome were included. Z-scores were calculated after the acquisition of CSP images. Normal CSP width Z-scores formulae were constructed based on gestational age (GA) by performing a standard regression analysis followed by weighted regression of absolute residual values. Subsequently, the Mann–Whitney U test was used to compare the CSP width Z-scores between normal and 18-trisomy groups. Formulae calculating CSP width Z-scores were constructed. Normal fetal CSP width was significantly correlated with GA (R2 = 0.50, p <.01). In 18-trisomy group, 69% (34/49) fetuses displayed enlarged fetal CSP width and CSP width Z-scores (p <.01). The CSP width Z-scores formulae established in the current study can provide a quantitative basis for the prenatal diagnosis of 18-trisomy syndrome. Enlarged CSP width Z-score may serve as a novel prenatal diagnostic marker for the 18-trisomy syndrome. [ABSTRACT FROM AUTHOR]