Utility of Fetal Cardiac MRI for Complex Single Ventricle Anatomy

Description of Clinical Presentation: We present a case in which fetal cardiac magnetic resonance imaging (fCMR) with 3-Dimensional modeling was instrumental in establishing an accurate diagnosis, guiding parental counseling, and informing perinatal management. Fetal echocardiography in a 26-year-old primigravida woman at 31 weeks of gestation for suspected single ventricle anatomy demonstrated HLHS with mitral and aortic atresia and concern for intact atrial septum. Visualization of the pulmonary veins was limited due to advanced gestational age and fetal position, with some concern for anomalous pulmonary venous connection to the superior vena cava (SVC).

Diagnostic Techniques and Their Most Important Findings: Given the diagnostic uncertainty, fCMR was performed, which demonstrated that all four pulmonary veins had normal drainage to the left atrium, with additional anomalous connection from the right upper pulmonary vein to the SVC. The fMRI dataset was rendered into a three-dimensional model, allowing the multidisciplinary team to review the anatomy and develop a detailed delivery plan.

The infant was delivered via planned Cesarean section at 38 weeks' gestation and underwent atrial septectomy on day of life, and subsequently underwent bilateral PA band placement and PDA stenting at 5 weeks of life with no emergent pulmonary vein intervention. CT angiography at two weeks of life closely matched the fCMR model.

Learning Points from this Case: This case illustrates the complementary role of fCMR when evaluating complex pulmonary venous anatomy. By enabling high-resolution visualization of extracardiac vascular structures, fMRI can reveal critical features such as drainage patterns and potential obstruction. VR modeling allowed effective multidisciplinary team planning, facilitating consensus on delivery location, timing, and postnatal management. The strong correlation between prenatal and postnatal VR models validated the reliability of this approach.

Figure 1. Side-by-side lateral view of prenatal and postnatal 3D reconstructions derived from fetal CMR and postnatal CT angiography, respectively, demonstrating concordant complex supracardiac anomalous pulmonary venous return in the setting of HLHS.
posterior view of Side-by-side prenatal and postnatal 3D reconstructions derived from fetal CMR and postnatal CT angiography, respectively, demonstrating concordant complex supracardiac anomalous pulmonary venous return in the setting of HLHS.