Optimized Automated Cardiac MR Scar Quantification with GAN-Based Data Augmentation

TL;DR

This paper presents a cascaded deep learning pipeline augmented with synthetic data from GANs, significantly improving automated cardiac scar and myocardium segmentation accuracy in MRI compared to traditional methods.

Contribution

The study introduces a novel cascaded neural network pipeline trained with GAN-generated synthetic data, enhancing robustness and accuracy in cardiac MRI scar quantification.

Findings

Cascaded pipeline outperforms single nnU-Net in segmentation accuracy.

Synthetic data augmentation improves scar segmentation DSC by 0.06.

Achieved high DSC scores comparable to manual segmentation.

Abstract

Background: The clinical utility of late gadolinium enhancement (LGE) cardiac MRI is limited by the lack of standardization, and time-consuming postprocessing. In this work, we tested the hypothesis that a cascaded deep learning pipeline trained with augmentation by synthetically generated data would improve model accuracy and robustness for automated scar quantification. Methods: A cascaded pipeline consisting of three consecutive neural networks is proposed, starting with a bounding box regression network to identify a region of interest around the left ventricular (LV) myocardium. Two further nnU-Net models are then used to segment the myocardium and, if present, scar. The models were trained on the data from the EMIDEC challenge, supplemented with an extensive synthetic dataset generated with a conditional GAN. Results: The cascaded pipeline significantly outperformed a single nnU-Net directly segmenting both the myocardium (mean Dice similarity coefficient (DSC) (standard deviation (SD)): 0.84 (0.09) vs 0.63 (0.20), p < 0.01) and scar (DSC: 0.72 (0.34) vs 0.46 (0.39), p < 0.01) on a per-slice level. The inclusion of the synthetic data as data augmentation during training improved the scar segmentation DSC by 0.06 (p < 0.01). The mean DSC per-subject on the challenge test set, for the cascaded pipeline augmented by synthetic generated data, was 0.86 (0.03) and 0.67 (0.29) for myocardium and scar, respectively. Conclusion: A cascaded deep learning-based pipeline trained with augmentation by synthetically generated data leads to myocardium and scar segmentations that are similar to the manual operator, and outperforms direct segmentation without the synthetic images.