Analysis of 3-Dimensional Arch Anatomy, Vascular Flow, and Postnatal Outcome in Cases of Suspected Coarctation of the Aorta Using Fetal Cardiac Magnetic Resonance Imaging

Abstract

Background: Identifying fetuses at risk of severe neonatal coarctation of the aorta (CoA) can be lifesaving but is notoriously challenging in clinical practice with a high rate of false positives. Novel fetal 3-dimensional and phase-contrast magnetic resonance imaging (MRI) offers an unprecedented means of assessing the human fetal cardiovascular system before birth. We performed detailed MRI assessment of fetal vascular morphology and flows in a cohort of fetuses with suspected CoA, correlated with the need for postnatal intervention. Methods: Women carrying a fetus with suspected CoA on echocardiography were referred for MRI assessment between 26 and 36 weeks of gestation, including high-resolution motion-corrected 3-dimensional volumes of the fetal heart and phase-contrast flow sequences gated with metric optimized gating. The relationship between aortic geometry and vascular flows was then analyzed and compared with postnatal outcome. Results: Seventy-two patients (51 with suspected fetal CoA and 21 healthy controls) underwent fetal MRI with motion-corrected 3-dimensional vascular reconstructions. Vascular flow measurements from phase-contrast sequences were available in 53 patients. In the CoA group, 25 of 51 (49%) required surgical repair of coarctation after birth; the remaining 26 of 51 (51%) were discharged without neonatal intervention. Reduced blood flow in the fetal ascending aorta and at the aortic isthmus was associated with increasing angulation ( P =0.005) and proximal displacement ( P =0.006) of the isthmus and was seen in both true positive and false positive cases. A multivariate logistic regression model including aortic flow and isthmal displacement explained 78% of the variation in outcome and correctly predicted the need for intervention in 93% of cases. Conclusions: Reduced blood flow though the left heart is associated with important configurational changes at the aortic isthmus in fetal life, predisposing to CoA when the arterial duct closes after birth. Novel fetal MRI techniques may have a role in both understanding and accurately predicting severe neonatal CoA.

Cerebral Blood Flow Monitoring in High-Risk Fetal and Neonatal Populations

“…One major obstacle to this imaging is the necessity of timing image acquisition with the cardiac cycle (47)(48)(49)(50)(51). Cardiac gating is used to time data acquisition with specific phases of the cardiac cycle, and MRI-compatible fetal ECG devices are now available (48,(51)(52)(53)(54)(55). This technology has now been applied to fetal disease states including IUGR (54) as well as the fetus with cardiac malformations (38).…”

3D MRI atlases of congenital aortic arch anomalies and normal fetal heart: application to automated multi-label segmentation

“…The extraction of vessel diameter was performed in VMTK toolbox [14]. Importantly, the CoA atlas represents an averaged state of all CoA types [5] as the input cases had varying position and degree of arch narrowing.…”

“…At our institution, the main clinical referral indications for 3D T2w fetal cardiac MRI (CMR) [1] include suspected coarctation of the aorta (CoA), right aortic arch (RAA) with aberrant left subclavian artery (ALSA) and suspected double aortic arch (DAA). However, despite the reported improved diagnostic performance of 3D fetal CMR [1, 5], there is a lack of formalization of the MRI appearance of fetal cardiovascular anatomy. Furthermore, the currently employed 3D semi-automatic segmentation of the heart vasculature from T2w SVR images [1] requires time-consuming manual refinement, especially for multiple labels and is vulnerable to inter-observer bias.…”

Automated 3D reconstruction of the fetal thorax in the standard atlas space from motion-corrupted MRI stacks for 21-36 weeks GA range

“…B: The corresponding high-resolution SVR-reconstructed fetal thorax and 3D segmentation of the heart and vessels based on the pipeline proposed in (Lloyd et al, 2019). Since 2018, rigid SVR (Kuklisova-Murgasova et al, 2012Kainz et al, 2015) has been employed on regular basis for averaged 3D reconstruction of the 3D fetal heart anatomy as a part of the current clinical practice for diagnosis of fetal congenital heart disease (CHD) (Lloyd et al, 2019(Lloyd et al, , 2021 at Evelina London Children's Hospital. An example of a 30 weeks GA cardiac MRI (CMR) dataset in Fig.…”

“…Since 2018, rigid SVR (Kuklisova-Murgasova et al, 2012;Kainz et al, 2015) has been employed on regular basis for averaged 3D reconstruction of the 3D fetal heart anatomy as a part of the current clinical practice for diagnosis of fetal congenital heart disease (CHD) (Lloyd et al, 2019(Lloyd et al, , 2021 at Evelina London Children's Hospital with more than 300 reconstructions performed since 2017. An example of a 30 weeks GA cardiac MRI (CMR) dataset in Fig.…”