Memon, S.Q., Bhatti, S., Muhammad Moazzam Jawaid, Memon, M. and Usman, G. 2026. The Hierarchical Feature Learning for Accurate Pixel-Wise Segmentation of Cardiac Structures in CT Images: A Comprehensive Evaluation of U-Net Variants. International Journal of Innovations in Science & Technology. 8, 2 (Apr. 2026), 728–742. DOI:https://doi.org/10.33411/IJIST/1868.