Neonates with congenital brain malformations (CBM) have historically been excluded from neuroimaging studies in congenital heart disease (CHD). We describe CBMs, genetic diagnoses, and impact on clinical care. This single-centre retrospective study included neonates with CHD born between January 2018-June 2023 diagnosed with CBM on MRI performed as part of routine pre- and post-operative imaging or where there were clinical concerns. CBMs were identified in 21 of 438 (4.8%, 95% CI 3.1-7.3) neonates with CHD. 6/21 neonates had single ventricle physiology, 11/21 had biventricular physiology without arch obstruction and 5/21 had biventricular physiology with arch obstruction. Malformations of cortical development were present in 10/21 neonates, abnormalities of midline structures were noted in 10/21 neonates, and 10/21 presented with brainstem and cerebellar malformations (Figure 1). 9/21 had more than one type of CBM. 20/21 neonates underwent genetic testing. A genetic diagnosis was found in 15/20 neonates (75%, 95%CI 52.8-89.2): 6/20 had a chromosomal anomaly and 9/20 had a pathogenic variant in a single gene. 9/21 neonates had extracardiac features noted before brain MRI completion. In 11/20 neonates, diagnosis of CBM on MRI prompted genetic investigations and 6/21 neonates underwent palliation following diagnosis of the CBM. While CBMs in neonates with CHD are rare, early diagnosis with MRI was important for the initiation of genetic testing and directing goals of care.

Vanna Kazazian
The Hospital for Sick Children
Canada

Helen Branson
The Hospital for Sick Children
Canada

Rebekah Jobling
The Hospital for Sick Children
Canada

Linh Ly
The Hospital for Sick Children
Canada

Laura Zahavich
The Hospital for Sick Children
Canada

Steven Miller
BC Children's Hospital
Canada

Mike Seed
This Hospital for Sick Children
Canada

Vann Chau
The Hospital for Sick Children
Canada

Thiviya Selvanathan
BC Children's Hospital
Canada