collaborators

7 papers

cs.CV2026

Graph Representation Learning of Longitudinal Medical Imaging Trajectories for Treatment Response Prediction

Johannes Kiechle, Richard Osuala, Daniel M. Lang +5

In patients with breast cancer, pathological complete response (pCR) has been established as a clinically meaningful surrogate marker for long-term outcomes. While commonly treated…

cs.LG2026

Entropy Minimization without Model Collapse: Mitigating Prediction Bias in Medical Imaging

Tim Nielen, Sameer Ambekar, Johannes Kiechle +2

Entropy minimization (EM) is the dominant objective for test-time adaptation, yet its failure mode, model collapse, remains poorly understood. In this work, we show that distributi…

cs.LG2026

Hierarchical Adaptive networks with Task vectors for Test-Time Adaptation

Sameer Ambekar, Marta Hasny, Laura Daza +2

Test-time adaptation allows pretrained models to adjust to incoming data streams, addressing distribution shifts between source and target domains. However, standard methods rely o…

cs.LG2026

The Mean is the Mirage: Entropy-Adaptive Model Merging under Heterogeneous Domain Shifts in Medical Imaging

Sameer Ambekar, Reza Nasirigerdeh, Peter J. Schuffler +3

Model merging under unseen test-time distribution shifts often renders naive strategies, such as mean averaging unreliable. This challenge is especially acute in medical imaging, w…

cs.CV2026

MedDIFT: Multi-Scale Diffusion-Based Correspondence in 3D Medical Imaging

Xingyu Zhang, Anna Reithmeir, Fryderyk Kögl +3

Accurate spatial correspondence between medical images is essential for longitudinal analysis, lesion tracking, and image-guided interventions. Medical image registration methods r…

eess.IV2025

TomoGraphView: 3D Medical Image Classification with Omnidirectional Slice Representations and Graph Neural Networks

Johannes Kiechle, Stefan M. Fischer, Daniel M. Lang +5

The sharp rise in medical tomography examinations has created a demand for automated systems that can reliably extract informative features for downstream tasks such as tumor chara…