Multi-task learning for joint weakly-supervised segmentation and aortic
  arch anomaly classification in fetal cardiac MRI
Paula Ramirez Alena Uus Milou P. M. van Poppel Irina Grigorescu Johannes K. Steinweg David F. A. Lloyd Kuberan Pushparajah Andrew P. King Maria Deprez
Congenital Heart Disease (CHD) is a group of cardiac malformations present
already during fetal life, representing the prevailing category of birth
defects globally. Our aim in this study is to aid 3D fetal vessel topology
visualisation in aortic arch anomalies, a group which encompasses a range of
conditions with significant anatomical heterogeneity. We present a multi-task
framework for automated multi-class fetal vessel segmentation from 3D black
blood T2w MRI and anomaly classification. Our training data consists of binary
manual segmentation masks of the cardiac vessels' region in individual subjects
and fully-labelled anomaly-specific population atlases. Our framework combines
deep learning label propagation using VoxelMorph with 3D Attention U-Net
segmentation and DenseNet121 anomaly classification. We target 11 cardiac
vessels and three distinct aortic arch anomalies, including double aortic arch,
right aortic arch, and suspected coarctation of the aorta. We incorporate an
anomaly classifier into our segmentation pipeline, delivering a multi-task
framework with the primary motivation of correcting topological inaccuracies of
the segmentation. The hypothesis is that the multi-task approach will encourage
the segmenter network to learn anomaly-specific features. As a secondary
motivation, an automated diagnosis tool may have the potential to enhance
diagnostic confidence in a decision support setting. Our results showcase that
our proposed training strategy significantly outperforms label propagation and
a network trained exclusively on propagated labels. Our classifier outperforms
a classifier trained exclusively on T2w volume images, with an average balanced
accuracy of 0.99 (0.01) after joint training. Adding a classifier improves the
anatomical and topological accuracy of all correctly classified double aortic
arch subjects.