Foetal disruptive brain injuries: Diagnosing the underlying pathogenetic mechanisms with cranial ultrasonography

Antenatal destructive events affecting the central nervous system of the foetus lead to disruptive brain lesions that are often associated with impaired neurodevelopment. The pathogenesis of these lesions encompasses a range of causes, including haemorrhagic, embolic, or other vascular events; exposure to teratogens, such as drugs or substance abuse; congenital brain infections; genetic conditions; and metabolic disorders. Cranial ultrasonography is the first-line imaging modality to diagnose these antepartum brain lesions in the newborn infant; it is often complemented by brain magnetic resonance imaging to detect associated neuronal dysmigration and dysplasia. Using a pictorial approach, a differential diagnosis of foetal disruptive brain lesions and common findings related to antenatal brain damage can be made, including antenatal haemorrhagic and ischaemic brain injuries, porencephaly, schizencephaly, multicystic encephalomalacia, and hydranencephaly, as well as germinolytic cysts and lenticulostriate vasculopathy. The main conditions associated with foetal brain disruption, such as genetic cerebral vascular diseases, monochorionic twin pregnancies, congenital heart disease, maternal drug use, congenital infections, and inborn errors of metabolism can be used to illustrate typical imaging patterns that, when combined with clinical presentation, can assist in identifying the underlying mechanisms and causes, thus supporting individualized patient management.