Fetal Cardiac Magnetic Resonance Imaging in the Evaluation of Left Ventricular Diverticula: Two Case Presentations of Fetal Ventricular Outpouchings

Description of Clinical Presentation: We present 2 cases of left ventricular (LV) diverticula in fetal life, which were evaluated using fetal cardiac magnetic resonance imaging (FCMR). In case 1, a 32-yr-old G2P1 female was referred for fetal echo for routine in vitro fertilization screening, during which an LV outpouching was seen. In case 2, a 31-yr-old G2P1 female was referred to fetal cardiology from a remote outside clinic due to concern for total anomalous pulmonary venous return (TAPVR). Fetal echo suggested intracardiac TAPVR to the coronary sinus, and the LV function appeared diminished with an unusual outpouching.

Diagnostic Techniques and Their Most Important Findings: FCMR was performed at 34 wks gestation in case 1 and 35 wks gestation in case 2 on a 1.5T magnet. The intracardiac anatomy was assessed using fetal Doppler-derived ECG gated balanced steady state free procession cine imaging with 5 mm slices in axial, 4-chamber, and short-axis planes. The vascular anatomy was assessed using T2-weighted black blood single shot turbo spin echo 2D stacks at 2.5 mm slice thickness, followed by a slice to volume reconstruction to create a 1.25 mm isotropic 3D dataset.

FCMR in case 1 showed a moderate contractile LV outpouching, which was felt to be an LV diverticulum along the mid-to-apical lateral wall (figure 1), with no additional defects and preserved systolic function. A small pericardial effusion was seen. The infant was delivered at an outside regional facility, required no intervention, and has remained well on follow-up. No postnatal CMR was done.

FCMR in case 2 confirmed anomalous drainage of at least 3 pulmonary veins to the coronary sinus. A large lateral contractile LV outpouching was seen, consistent with a diverticulum (figure 2). The LV function was mildly diminished. No pulmonary lymphangiectasia was seen. Due to the far distance of the family’s home, delivery was coordinated at our center. The fetal findings were presented in multidisciplinary conference for surgical awareness. The infant was well after birth and observed for 10d. Postnatal echo and CMR confirmed the prenatal findings of TAPVR to the coronary sinus and large LV diverticulum with diminished systolic function. He was discharged back to his hometown with close outpatient cardiology follow up and returned for TAPVR repair at 6 wks without complications. He has remained well on outpatient follow up with a persistent LV diverticulum and normalized function.

Learning Points from this Case: FCMR provides complementary prognostication and perinatal planning for various congenital heart diseases. In these cases, the diverticula were well characterized on fCMR using fetal Doppler-derived ECG gated cine imaging, allowing the contractile nature of the outpouchings to be seen. The fetus in case 1 did not have an over-medicalized postnatal hospitalization, allowing for a safe local delivery and good utilization of resources. The fetus in case 2 was able to be appropriately diagnosed and allowed for surgical planning prior to birth.

Figure 1: Fetal cardiac magnetic resonance imaging in a 34 week fetus. Fetal Doppler-derived ECG gated balanced steady state free procession cine imaging in 4-chamber plane (left panel) and short axis plane (right panel) shows an isolated left ventricular diverticulum (yellow arrow) measuring 9 × 3 mm in systole and 14 × 4 mm in diastole and a small anterior pericardiac effusion (red arrow).
Figure 2: Fetal cardiac magnetic resonance (CMR) imaging in a 35 week fetus. Fetal Doppler-derived ECG gated balanced steady state free procession cine imaging in 4-chamber plane (left panel) shows a dilated coronary sinus with anomalous pulmonary venous drainage of at least three pulmonary veins draining into the coronary sinus (yellow arrow). Additionally, a large mid to apical left ventricular diverticulum was identified measuring 25 × 9 mm in diastole and 17 × 7 mm in systole (red arrow). Cine imaging on postnatal CMR (right panel) done in the first week of life with a comparative 4 chamber plane showing the left ventricular diverticulum (red arrow).