Fetal MRI for cardiopulmonary anomalies: what the pediatric cardiologist and surgeon need to know.

PURPOSE OF REVIEW: Advances in fetal cardiac magnetic resonance imaging (CMR) have expanded its role as an adjunct to expert fetal echocardiography in the prenatal evaluation of complex cardiopulmonary anomalies. This review outlines an evidence-based framework for integrating fetal CMR when it provides diagnostic or prognostic information that can informs counseling, delivery planning, or postnatal management.

RECENT FINDINGS: Fetal CMR offers high-resolution, multiplanar imaging with superior soft-tissue contrast and wide field of view, enabling improved assessment of cardiopulmonary structures where echocardiography is limited by technical or physiologic factors, or when expert echocardiography raises clinically relevant questions. MRI enables improved delineation of aortic arch and pulmonary venous anatomy, characterization of pulmonary parenchymal changes, and quantify lung and ventricular volumetry without relying on geometric assumptions. Emerging flow-based techniques allow evaluation of fetal hemodynamics and cardiovascular physiology beyond static imaging. These technologies provide diagnostic and prognostic information in select, often critical, congenital heart diseases.

SUMMARY: Fetal cardiac CMR serves as a complementary modality to expert echocardiography when applied selectively to address clinically meaningful diagnostic or prognostic questions. However, limited availability, technical complexity, and the need for specialized expertise currently constrain widespread adoption. Continued technical refinement and outcome-based validation are required before fetal CMR can be routinely integrated into clinical practice.