Implicit U-KAN2.0: Dynamic, Efficient and Interpretable Medical Image Segmentation

Chun-Wun Cheng*1
Yining Zhao*2
Yanqi Cheng1
Javier Montoya3,4,5
Carola-Bibiane Schönlieb1
Angelica I. Aviles-Rivero6

1Department of Applied Mathematics and Theoretical Physics, University of Cambridge, UK
2Siebel School of Computing and Data Science, University of Illinois Urbana-Champaign, USA
3Lucerne School of Computer Science and Information Technology, Lucerne University of Applied Sciences and Arts (HSLU), Switzerland
4Lucerne Cantonal Hospital, Switzerland
5Zurich University of Applied Sciences (ZHAW), Switzerland
6Yau Mathematical Sciences Center, Tsinghua University, China
*Equal contribution


affiliations

[Paper]
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Abstract

Image segmentation is a fundamental task in both image analysis and medical applications. State-of-the-art methods predominantly rely on encoder-decoder architectures with a U-shaped design, commonly referred to as U-Net. Recent advancements integrating transformers and MLPs improve performance but still face key limitations, such as poor interpretability, difficulty handling intrinsic noise, and constrained expressiveness due to discrete layer structures, often lacking a solid theoretical foundation.In this work, we introduce Implicit U-KAN 2.0, a novel U-Net variant that adopts a two-phase encoder-decoder structure. In the SONO phase, we use a second-order neural ordinary differential equation (NODEs), called the SONO block, for a more efficient, expressive, and theoretically grounded modeling approach. In the SONO-MultiKAN phase, we integrate the second-order NODEs and MultiKAN layer as the core computational block to enhance interpretability and representation power. Our contributions are threefold. First, U-KAN 2.0 is an implicit deep neural network incorporating MultiKAN and second order NODEs, improving interpretability and performance while reducing computational costs. Second, we provide a theoretical analysis demonstrating that the approximation ability of the MultiKAN block is independent of the input dimension. Third, we conduct extensive experiments on a variety of 2D and a single 3D dataset, demonstrating that our model consistently outperforms existing segmentation networks.


Experiments



Paper and Supplementary Material


Chun-Wun Cheng*, Yining Zhao*, Yanqi Cheng, Javier Montoya, Carola-Bibiane Schönlieb, Angelica I Aviles-Rivero.
Implicit U-KAN2.0: Dynamic, Efficient and Interpretable Medical Image Segmentation
MICCAI 2025

[Bibtex]


Acknowledgements

CWC is supported by the Swiss National Science Foundation (SNSF) under grant number 20HW-1 220785. YC is funded by an AstraZeneca studentship and a Google studentship. CBS acknowledges support from the Philip Leverhulme Prize, the Royal Society Wolfson Fellowship, the EPSRC advanced career fellowship EP/V029428/1, EPSRC grants EP/S026045/1 and EP/T003553/1, EP/N014588/1, EP/T017961/1, the Wellcome Innovator Awards 215733/Z/19/Z and 221633/Z/20/Z, the European Union Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No. 777826 NoMADS, the Cantab Capital Institute for the Mathematics of Information and the Alan Turing Institute. AIAR gratefully acknowledges the support from Yau Mathematical Sciences Center, Tsinghua University.