Outcome of fetuses with cerebral ventriculomegaly and septum pellucidum leaflet abnormalities

Abstract

Objective: The objective of this study was to assess the outcomes of the prenatal diagnosis of septal leaflet abnormalities in fetuses referred for prenatal imaging with a finding of ventriculomegaly.

Materials and methods: This study is a retrospective review of fetuses with a diagnostic code of septal leaflet abnormalities from a larger prospective study. Four hundred twenty-five pregnant women with 433 fetuses referred for ventriculomegaly were imaged with ultrasound and MRI between July 1, 2003, and May 15, 2009. Four to six radiologists independently reviewed sonographic and MR images and recorded lateral ventricular diameters at the atrium and frontal horns, ventricular configuration, and the presence of ventriculomegaly and of other CNS abnormalities. Final prenatal ultrasound, MRI, and overall diagnoses were decided by consensus. Fetuses with a diagnostic code of septal leaflet abnormalities were identified, and birth outcome, autopsy findings, postnatal imaging, and postnatal follow-up examinations were obtained. The analysis of covariance, controlling for gestational age, was used to compare ventricular dimensions between fetuses with septal leaflet abnormalities and fetuses with isolated ventriculomegaly. Interrater agreement for the detection of septal leaflet abnormalities was assessed with kappa statistics. Interrater agreement and intrarater agreement for frontal horn measurements were assessed by variance components analysis.

Results: Twenty-three fetuses had septal leaflet abnormalities and 229 had isolated ventriculomegaly. Atrial and frontal horn diameters, adjusted for gestational age, were 77% and 98% larger, respectively, in fetuses with septal leaflet abnormalities than in fetuses with isolated ventriculomegaly (p < 0.0001). Before the consensus conference, agreement among ultrasound readers was moderate (κ = 0.54) and among MR readers, good (κ = 0.69). Additional CNS findings were seen on MRI in 12 of 23 fetuses (52%). Eleven pregnancies with septal leaflet abnormalities underwent termination and 12 progressed to livebirth; of the 12 livebirths, three neonates died. Neurodevelopmental follow-up was abnormal in all surviving children.

Conclusion: A septal leaflet abnormality in the setting of ventriculomegaly is most frequently associated with other CNS abnormalities and is associated with postnatal developmental delay.

Figures

Fig 1

Fetus at 29 weeks (A–C) and after birth (D,E) with ventriculomegaly, absence of septal leaflets, and postnatal additional diagnosis of dysmorphic corpus callosum. (A) Coronal US shows enlarged frontal horns with absence of the septal leaflets. Coronal (B) and axial (C) T2 weighted MR images show enlarged lateral and third ventricles and absent septal leaflets. Coronal (D) and sagittal (E) head US show the enlarged frontal horns, absence of the septum pellucidum and thin, dysmorphic corpus callosum.

Fig. 2

Fetus at 31 weeks gestational age with absent septal leaflets and schizencephaly. (A) Coronal T2-weighted image shows absent septal leaflets and open-lipped schizencephaly. (B) Sagittal T2-weighted MRI image shows normal appearance to midline structures, including corpus callosum.

Fig. 3

Fetus at 34 weeks gestational age (A–D) and postnatal (E–F) with Dandy Walker malformation, hydrocephalus, and absent septal leaflets. (A) Coronal US shows enlarged ventricles, fused frontal horns and absent septal leaflets. Inferiorly the frontal horns appear pointed. (B) Sagittal US shows the enlarged posterior fossa with severe vermian hypoplasia and elevated tentorium consistent with Dandy Walker malformation. Head size was enlarged (biparietal diameter greater than expected for 40 weeks gestational age). Only the anterior portion of the corpus callosum was visualized. Coronal (C) and sagittal (D) T2-weighted MR images show similar findings. Note the mass effect on the brainstem, which appears slightly thin. (E) Coronal postnatal head US shows absent septal leaflets, severely enlarged ventricles, and the anterior portion of the corpus callosum. (F) T1-weighted sagittal view shows similar findings to those seen prenatally, as well as a small brainstem.

Fig. 4

Fetus at 21 weeks gestational age with absent septal leaflets and unilateral microphthalmia. (A) T2 weighted coronal view shows dilated frontal horns with absent septal leaflets. (B) Axial view through orbits shows a smaller globe on the left than on the right.