Dataset Information

Altered 4-D magnetic resonance imaging flow characteristics in complex congenital aortic arch repair.

ABSTRACT:

Background

Interrupted aortic arch (IAA) is a rare but severe congenital abnormality often associated with bicuspid aortic valve (BAV). Complex re-interventions are often needed despite surgical advances, but the impact of aortic hemodynamics in repaired patients is unknown.

Objective

Investigate effect of IAA repairs on aortic hemodynamics, wall shear stress and flow derangements via 4-D flow MRI.

Materials and methods

We retrospectively analyzed age- and gender-matched cohorts (IAA [n=6], BAV alone [n=6], controls [n=6]) undergoing cardiac MRI including 4-D flow. Aortic dimensions were measured from standard MR angiography. We quantified peak systolic velocities, regurgitant fractions and wall shear stress in the ascending aorta (AAo), transverse arch and descending aorta (DAo) from 4-D flow, and we graded helix/vortex flow patterns from 3-D blood flow visualization.

Results

Children and young adults with IAA had a wide range of arch dimensions, peak systolic velocities, regurgitant fractions and flow grades. Peak transverse arch systolic velocities were higher in patients with IAA versus controls (P=0.02). Flow derangements in the AAo were found in patients with IAA (median grade=2, 5/6 patients, P=0.04) and BAV (median grade=3, 5/6 patients, P=0.03) versus controls. Flow derangements in the DAo were only seen in patients with IAA (median grade=1, 5/6 patients, P=0.04), and 5/6 people with IAA had helical flow in head and neck vessels. Wall shear stress was increased in people with IAA along the superior transverse arch and proximal DAo versus controls (P=0.02).

Conclusion

Complex congenital aortic arch repairs can change aortic hemodynamics. Associated cardiac defects can further alter findings. Studies are warranted to investigate clinical implications in larger cohorts.

SUBMITTER: Desai LP

PROVIDER: S-EPMC6943192 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

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Publications

Altered 4-D magnetic resonance imaging flow characteristics in complex congenital aortic arch repair.

Desai Lajja P LP Berhane Haben H Husain Nazia N Robinson Joshua D JD Rigsby Cynthia K CK Markl Michael M

Pediatric radiology 20190831 1

<h4>Background</h4>Interrupted aortic arch (IAA) is a rare but severe congenital abnormality often associated with bicuspid aortic valve (BAV). Complex re-interventions are often needed despite surgical advances, but the impact of aortic hemodynamics in repaired patients is unknown.<h4>Objective</h4>Investigate effect of IAA repairs on aortic hemodynamics, wall shear stress and flow derangements via 4-D flow MRI.<h4>Materials and methods</h4>We retrospectively analyzed age- and gender-matched co ...[more]

PMID: 31473788

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Project description:PurposeCardiovascular diseases remain the number one death cause worldwide. Preclinical 4D flow phase contrast magnetic resonance imaging can provide substantial insights in the analysis of aortic pathophysiologies in various animal models. These insights may allow a better understanding of pathophysiologies, therapy monitoring, and can possibly be translated to humans. This study provides a framework to acquire the velocity field within the aortic arch. It analyses important flow values at different locations within the aortic arch. Imaging parameters with high temporal and spatial resolution are provided, that still allow combining this time-consuming method with other necessary imaging-protocols.MethodsA new setup was established where a prospectively gated 4D phase contrast sequence is combined with a highly sensitive cryogenic coil on a preclinical magnetic resonance scanner. The sequence was redesigned to maintain a close to steady state condition of the longitudinal magnetization and hence to overcome steady state artifacts. Imaging parameters were optimized to provide high spatial and temporal resolution. Pathline visualizations were generated from the acquired velocity data in order to display complex flow patterns.ResultsOur setup allows data acquisition with at least two times the rate than that of previous publications based on Cartesian encoding, at an improved image quality. The "steady state" sequence reduces observed artifacts and provides uniform image intensity over the heart cycle. This made possible quantification of blood speed and wall shear stress (WSS) within the aorta and its branches. The highest velocities were observed in the ascending aorta with 137.5 ± 8 cm/s. Peak velocity values in the Brachiocephalic trunk were 57 ± 12 cm/s. Quantification showed that the peak flow occurs around 20 ms post R-wave in the ascending aorta. The highest mean axial wall shear stress was observed in the analysis plane between the left common carotid artery (LCCA) and the left subclavian artery. A stable image quality allows visualizing complex flow patterns by means of streamlines and for the first time, to the best of our knowledge, pathline visualizations from 4D flow MRI in mice.ConclusionThe described setup allows analyzing pathophysiologies in mouse models of cardiovascular diseases in the aorta and its branches with better image quality and higher spatial and temporal resolution than previous Cartesian publications. Pathlines provide an advanced analysis of complex flow patterns in the murine aorta. An imaging protocol is provided that offers the possibility to acquire the aortic arch at sufficiently high resolution in less than one hour. This allows the combination of the flow assessment with other multifunctional imaging protocols.

Project description:BackgroundImage-domain motion correction of black-blood contrast T2-weighted fetal cardiovascular magnetic resonance imaging (CMR) using slice-to-volume registration (SVR) provides high-resolution three-dimensional (3D) images of the fetal heart providing excellent 3D visualisation of vascular anomalies [1]. However, 3D segmentation of these datasets, important for both clinical reporting and the application of advanced analysis techniques is currently a time-consuming process requiring manual input with potential for inter-user variability.MethodsIn this work, we present novel 3D fetal CMR population-averaged atlases of normal and abnormal fetal cardiovascular anatomy. The atlases are created using motion-corrected 3D reconstructed volumes of 86 third trimester fetuses (gestational age range 29-34 weeks) including: 28 healthy controls, 20 cases with postnatally confirmed neonatal coarctation of the aorta (CoA) and 38 vascular rings (21 right aortic arch (RAA), 17 double aortic arch (DAA)). We used only high image quality datasets with isolated anomalies and without any other deviations in the cardiovascular anatomy.In addition, we implemented and evaluated atlas-guided registration and deep learning (UNETR) methods for automated 3D multi-label segmentation of fetal cardiac vessels. We used images from CoA, RAA and DAA cohorts including: 42 cases for training (14 from each cohort), 3 for validation and 6 for testing. In addition, the potential limitations of the network were investigated on unseen datasets including 3 early gestational age (22 weeks) and 3 low SNR cases.ResultsWe created four atlases representing the average anatomy of the normal fetal heart, postnatally confirmed neonatal CoA, RAA and DAA. Visual inspection was undertaken to verify expected anatomy per subgroup. The results of the multi-label cardiac vessel UNETR segmentation showed 100[Formula: see text] per-vessel detection rate for both normal and abnormal aortic arch anatomy.ConclusionsThis work introduces the first set of 3D black-blood T2-weighted CMR atlases of normal and abnormal fetal cardiovascular anatomy including detailed segmentation of the major cardiovascular structures. Additionally, we demonstrated the general feasibility of using deep learning for multi-label vessel segmentation of 3D fetal CMR images.

Dataset Information

Altered 4-D magnetic resonance imaging flow characteristics in complex congenital aortic arch repair.

Background

Objective

Materials and methods

Results

Conclusion

Publications

Altered 4-D magnetic resonance imaging flow characteristics in complex congenital aortic arch repair.

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