Detecting Clinical Hallucinations in LVLMs via Counterfactual Visual Grounding Uncertainty

Large vision-language models (LVLMs) are increasingly used for clinical image understanding, yet they remain vulnerable to \emph{hallucinations}--producing textual findings or attributes not supported by the image. We present a vision-traceable hallucination detection framework that audits arbitrary LVLM responses via visual evidence grounding, requiring neither modification nor internal access to the hidden states of LVLMs. Given an LVLM response, we extract visually verifiable entities and use a medical-domain-adapted Qwen-VL grounding verifier to localize each entity on the input image. To enhance the robustness of our detection method, we introduce a counterfactual entity perturbation method and estimate visual evidence uncertainty by contrasting factual and counterfactual grounding results. Specifically, we compute an entity-level uncertainty score from the positive confidence, counterfactual confidence, and their grounding overlap for binary hallucination decision-making. Experiments on multiple medical imaging modalities and LVLM backbones demonstrate that our method consistently improves hallucination detection performance over recent baselines, while providing interpretable localization evidence and strong cross-model transferability. Code and dataset are available at https://github.com/Agentic-CliniAI/CounterVHD.

Towards Efficient Model-Heterogeneity Federated Learning for Large Models

As demand grows for complex tasks and high-performance applications in edge computing, the deployment of large models in federated learning has become increasingly urgent, given their superior representational power and generalization capabilities. However, the resource constraints and heterogeneity among clients present significant challenges to this deployment. To tackle these challenges, we introduce HeteroTune, an innovative fine-tuning framework tailored for model-heterogeneity federated learning (MHFL). In particular, we propose a novel parameter-efficient fine-tuning (PEFT) structure, called FedAdapter, which employs a multi-branch cross-model aggregator to enable efficient knowledge aggregation across diverse models. Benefiting from the lightweight FedAdapter, our approach significantly reduces both the computational and communication overhead. Finally, our approach is simple yet effective, making it applicable to a wide range of large model fine-tuning tasks. Extensive experiments on computer vision (CV) and natural language processing (NLP) tasks demonstrate that our method achieves state-of-the-art results, seamlessly integrating efficiency and performance.