With advances in fetal MRI, more thoracic abnormalities are being diagnosed antenatally. Fetal MRI allows physicians to anticipate complex management issues like the congenital diaphragmatic hernia (CDH), lung changes due to anhydramnios, and assess the different lung lesions encountered in the fetus. MRI allows prognostic information in addition to screening for other findings. Fetal MRI can also help parents comprehend prognosis or offer reassurance.
Educational Goals / Teaching Points
This exhibit aims to review common chest and lung pathologies on fetal MRI; appreciate the imaging appearance of common in utero thoracic anomalies; and learn how MRI impacts patient management.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Lung anomalies can be secondary to extrinsic factors or from developmental disorders. Extrinsic factors like oligohydramnios or mass effect from congenital diaphragmatic hernias prevent proper lung expansion either from decreased volume internally or lack of volume to expand into. Intrinsic factors exist on a spectrum of bronchopulmonary anomalies including: bronchial atresia, congenital lobar hyperinflation, and cystic pulmonary airway malformations; combined lung and vascular abnormalities such as sequestrations and scimitar syndrome; and vascular anomalies including vascular malformations, arteriovenous malformations, and fistulas. Some of these lung and lung-related abnormalities have characteristic findings like scimitar syndrome, and others like congenital lobar overinflation have overlapping imaging features with other entities. Narrowing the diagnosis and providing more detailed information, even in overlapping entities can help guide clinical decision making.
Fetal MRI is becoming increasingly used to workup abnormalities seen on screening ultrasound. Because the lungs are physiologically filled with fluid in utero, MRI appearance of common diseases have different prenatal and postnatal appearances. MRI also has direct clinical impact for anticipating clinical needs, planning surgeries, and preparing families for expected outcomes. Recognizing some of the intrathoracic fetal abnormalities is a useful skill for anyone interested in fetal MRI.