EP01.02: Abnormal cavum septi pellucidi (CSP): experience of a tertiary centre

Abstract

Objectives: Cavum septum pellucidum (CSP) is an important intracranial structure that is necessarily visualised during routine second trimester sonography. A small or a large CSP may suggest abnormal cerebral development. Therefore, determination of CSP volumes can be useful. However, consistency of sonographic measurements for this relatively small structure is a concern. For this purpose, we sought to assess the reliability of CSP volume measurements with three-dimensional ultrasound between 19-24 weeks of gestational age in structurally normal fetuses. Methods: Three-dimensional Virtual Organ Computer-aided Analysis (VOCAL) software was used to calculate the CSP volume from transabdominal multiplanar datasets obtained during 99 consecutive normal fetal ultrasound examinations within a single unit. Agreement among 3 independent observers with different experience levels of ultrasonography (year 2 obstetrics and gynecology resident, year 2 maternal-fetal medicine fellow, and maternal-fetal medicine specialist) was evaluated, using absolute agreement intraclass correlation coefficients (ICC) and 95% confidence intervals (CI). Results: Measurement of CSP volume was possible in all of the fetuses by all examiners. Interobserver agreement between fellow and specialist was relatively high (ICC, 0.78; 95% CI, 0.70-0.85), whereas limited ultrasound experience (resident) was associated with fair agreement with other observers (ICC for resident and specialist, 0.50; 95 CI%, 0.29-0.65 and ICC for resident and fellow, 0.57; 95% CI, 0.38-0.71). Conclusions: Three-dimensional ultrasound CSP calculations using VOCAL software between 19-24 weeks of gestational age seem feasible, but are reliable only when evaluated by an examiner with particular fetal sonography experience. Objectives: To analyse the outcome of fetuses detected with absence of a normal CSP in the last 5 years, in the Prenatal Diagnosis Unit of our tertiary centre. Methods: We performed a retrospective review of the cases with abnormal CSP evaluated in our tertiary unit, diagnosed between January 2012 and February 2016. The fetal anatomy was evaluated in all cases following the recommendations of the international guidelines. In abnormal CSP cases, fetal neurosonogram and an extended fetal anomaly scan were performed and amniocentesis was proposed to identify genetic disorders. Results: The absence of a normal CSP was observed in 0.49% of the cases (38/7740) examined for morphological purposes. Absent CSP was the initial observation that triggered further investigation and diagnosis of 7 cases with agenesis of corpus callosum and 2 septo-optic dysplasias. In heavily malformed brain cases, as the neural tube defects, hydrocephaly, porencephaly, schizencephaly and holoprozencephaly, the absence of CSP was only an observation, with less diagnostic importance and clinical implications. Almost half of the total abnormal CSP cases (16) associated genetic disorders, most of them with abnormal karyotype and all of them were associated with the absence of CSP. Cystic m...