Sustainable Ultralightweight U-Net-Based Architecture for Myocardium Segmentation
Abstract
1. Introduction
- We propose a novel ultralightweight U-Net-based model tailored for myocardium segmentation;
- We introduce a new dataset with manually segmented cardiac muscle areas, validated by specialists, which is publicly available from GitHub;
- We demonstrate comparable segmentation accuracy in terms of IoU and Dice coefficients, alongside significant reductions in model complexity and parameter count;
- Our work aligns with the Green AI trend by considering not only accuracy but also model size, computational complexity, and operational efficiency. We provide a thorough quantitative analysis of the model’s sustainability using FLOPs and parameter counts.
2. Related Work
2.1. Medical Image Segmentation
2.2. Green AI
3. Materials and Methods
3.1. Dataset
3.2. Architecture
4. Results
4.1. Evaluation Metrics
4.2. Obtained Results
- ResNet18-U-Net: This model follows the standard U-Net decoder architecture but uses a ResNet18 encoder. It contains approximately 14.3 million parameters. By using a ResNet18 backbone, the model can benefit from transfer learning, leveraging features learned from large-scale datasets such as ImageNet. The decoder is a custom upsampling path designed to match the feature maps from the ResNet layers via skip connections.
- Original U-Net: A widely used baseline architecture with four downsampling and four upsampling blocks, each composed of double convolution layers [28]. It was originally designed for biomedical image segmentation.
- Small U-Net: A simplified version of U-Net architecture with only two downsampling and two upsampling blocks.
- UwU-Net (Proposed): A lightweight version of U-Net with a reduced number of layers and parameters, making it almost twice as light as Small U-Net.
5. Discussion
6. Conclusions
- Further model explainability—In the current work, we have integrated explainability techniques into our architecture, incorporating Grad-CAM visualizations to highlight the image regions that most significantly influenced the segmentation output. These visualizations not only improve trust in the model’s decisions but also provide valuable feedback for clinicians by revealing patterns that are consistent with anatomical structures. Future work may extend this approach by exploring additional methods, such as integrated gradients or layer-wise relevance propagation, to provide complementary perspectives on model reasoning and further enhance clinical interpretability.
- Further energy-aware optimization—Although the proposed model demonstrates competitive performance, further optimization with respect to energy efficiency remains an important issue for future work. Advanced hyperparameter tuning or model pruning strategies could be employed to reduce the computational cost (e.g., FLOPs and total number of parameters) while potentially maintaining or even improving the segmentation performance. This is particularly relevant in the context of sustainable AI and deployment in resource-constrained environments.
- Extension to diagnostic classification systems—The current segmentation architecture could be extended to support classification tasks. For instance, by analyzing the segmented myocardium, the system could assist in detecting specific cardiac pathologies (e.g., myocardial infarction, fibrosis, or inflammation) based on extracted textural or morphological features. Integrating segmentation with classification may provide a comprehensive diagnostic pipeline that enhances clinical decision-making.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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| Model | Avg. | Min. | Max. | Std.dev. |
|---|---|---|---|---|
| UwU-Net (proposed) | 0.7889 | 0.7686 | 0.8173 | 0.0168 |
| UwU-Net + LeakyRelu (proposed) | 0.7697 | 0.7075 | 0.8139 | 0.0286 |
| Small U-Net | 0.7769 | 0.7347 | 0.8097 | 0.0195 |
| Original U-Net | 0.7896 | 0.7534 | 0.8154 | 0.0176 |
| ResNet18-U-Net | 0.7909 | 0.7787 | 0.8007 | 0.0076 |
| Model | Avg. | Min. | Max. | Std.dev. |
|---|---|---|---|---|
| UwU-Net (proposed) | 0.8780 | 0.8618 | 0.8938 | 0.0109 |
| UwU-Net + LeakyRelu (proposed) | 0.8648 | 0.8203 | 0.8920 | 0.0198 |
| Small U-Net | 0.8694 | 0.8343 | 0.8888 | 0.0153 |
| Original U-Net | 0.8784 | 0.8466 | 0.8926 | 0.0142 |
| ResNet18-U-Net | 0.8801 | 0.8713 | 0.8879 | 0.0058 |
| Model | FLOP [G] | Parameters [M] |
|---|---|---|
| UwU-Net (proposed) | 6.24 | 0.263 |
| UwU-Net + LeakyRelu (proposed) | 6.22 | 0.263 |
| Small U-Net | 11.02 | 0.467 |
| Original U-Net | 83.79 | 31.042 |
| ResNet18-U-Net | 8.16 | 14.321 |
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Filarecki, J.; Mockiewicz, D.; Giełczyk, A.; Kuźba-Kryszak, T.; Makarewicz, R.; Lewandowski, M.; Serafin, Z. Sustainable Ultralightweight U-Net-Based Architecture for Myocardium Segmentation. J. Clin. Med. 2025, 14, 7971. https://doi.org/10.3390/jcm14227971
Filarecki J, Mockiewicz D, Giełczyk A, Kuźba-Kryszak T, Makarewicz R, Lewandowski M, Serafin Z. Sustainable Ultralightweight U-Net-Based Architecture for Myocardium Segmentation. Journal of Clinical Medicine. 2025; 14(22):7971. https://doi.org/10.3390/jcm14227971
Chicago/Turabian StyleFilarecki, Jakub, Dorota Mockiewicz, Agata Giełczyk, Tamara Kuźba-Kryszak, Roman Makarewicz, Marek Lewandowski, and Zbigniew Serafin. 2025. "Sustainable Ultralightweight U-Net-Based Architecture for Myocardium Segmentation" Journal of Clinical Medicine 14, no. 22: 7971. https://doi.org/10.3390/jcm14227971
APA StyleFilarecki, J., Mockiewicz, D., Giełczyk, A., Kuźba-Kryszak, T., Makarewicz, R., Lewandowski, M., & Serafin, Z. (2025). Sustainable Ultralightweight U-Net-Based Architecture for Myocardium Segmentation. Journal of Clinical Medicine, 14(22), 7971. https://doi.org/10.3390/jcm14227971

