Problem-Based Obstetric Ultrasound 2nd Edition PDF Free Download
The lateral ventricles should be measured at the routine mid-trimester scan in the axial plane at the level of the cavum septi pellucidi, with the calipers aligned with the internal borders of the medial and lateral walls of the ventricle; this should be at the level of the glomus of the choroid plexus. Fetal ventriculomegaly is characterized by a dilatation of the lateral ventricles, with or without dilatation of the third or fourth ventricles. There is no internationally agreed upon terminology, but Table 1.1 shows two systems used. It can affect one (unilateral) or both ventricles (bilateral). When mild or moderate, it may be due to normal variation, but it also represents a common endpoint of various pathologic processes. As the outcome and prognosis depend on the underlying cause, investigations are aimed at determining this. Apart from the underlying etiology and the presence of associated structural/chromosomal anomalies, post-natal outcome depends on the progression of ventricular dilatation. In isolated abnormality (absence of pathology and progression), the outlook for mild ventriculomegaly (<15 mm) is good with >95% of babies having normal neurodevelopment. Associated major anomalies (cranial and extracranial) can be present in 50% of fetuses with VM, of which the most common are agenesis of the corpus callosum, posterior fossa malformations, and open spina bifida. The rate of associated anomalies in severe VM is higher than in mild VM.