MOTOR: Multimodal Optimal Transport via Grounded Retrieval in Medical Visual Question Answering
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Abstract (arXiv)
Medical visual question answering (MedVQA) plays a vital role in clinical decision-making by providing contextually rich answers to image-based queries. Although vision-language models (VLMs) are widely used for this task, they often generate factually incorrect answers. Retrieval-augmented generation addresses this challenge by providing information from external sources, but risks retrieving irrelevant context, which can degrade the reasoning capabilities of VLMs. Re-ranking retrievals, as introduced in existing approaches, enhances retrieval relevance by focusing on query-text alignment. However, these approaches neglect the visual or multimodal context, which is particularly crucial for medical diagnosis. We propose MOTOR, a novel multimodal retrieval and re-ranking approach that leverages grounded captions and optimal transport. It captures the underlying relationships between the query and the retrieved context based on textual and visual information. Consequently, our approach identifies more clinically relevant contexts to augment the VLM input. Empirical analysis and human expert evaluation demonstrate that MOTOR achieves higher accuracy on MedVQA datasets, outperforming state-of-the-art methods by an average of 6.45%. Code is available at https://github.com/BioMedIA-MBZUAI/MOTOR.
Key facts. Cited by 5 papers in the map (data through 14 Oct 2026). Builds on 26 of its 35 references that are in the map. First posted on arXiv 28 Jun 2025.
Builds on
26 of 35 references.
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14 more
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Citing papers per year: 2025: 1; 2026: 4.
5 papers.
- 2025HeteroRAG: A Heterogeneous Retrieval-Augmented Generation Framework for Medical Vision Language Taskscited by 1
- 2026Dual Causal Inference: Integrating Backdoor Adjustment and Instrumental Variable Learning for Medical VQAcited by 1
- 2026FLOWREADER: Min-Cost Flow Optimization for Multi-Modal Long Document Q&Acited by 1
- 2026OTCHA: Optimal Transport-driven Confidence-aware Latent Hub Alignment for Multi-View Medical Image Classificationcited by 0
- 2026An Empirical Analysis of Continual Learning for Heterogeneous Medical Visual Question Answeringcited by 0
- 2026An Empirical Analysis of Continual Learning for Heterogeneous Medical Visual Question Answering13 Jul 2026
- 2026OTCHA: Optimal Transport-driven Confidence-aware Latent Hub Alignment for Multi-View Medical Image Classification18 Jun 2026
- 2026FLOWREADER: Min-Cost Flow Optimization for Multi-Modal Long Document Q&A5 Jun 2026
- 2026Dual Causal Inference: Integrating Backdoor Adjustment and Instrumental Variable Learning for Medical VQA22 Apr 2026
- 2025HeteroRAG: A Heterogeneous Retrieval-Augmented Generation Framework for Medical Vision Language Tasks18 Aug 2025
Similar, not cited
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- 2024MedThink: Explaining Medical Visual Question Answering via Multimodal Decision-Making Rationale
- 2025Multimodal Retrieval-Augmented Generation with Large Language Models for Medical VQA
- 2026MedProb: Probing Internal Representations of Vision-Language Models for Medical Question Answering
- 2024OmniMedVQA: A New Large-Scale Comprehensive Evaluation Benchmark for Medical LVLM
- 2026Iterative Multimodal Retrieval-Augmented Generation for Medical Question Answering
- 2025Med-GRIM: Enhanced Zero-Shot Medical VQA using prompt-embedded Multimodal Graph RAG
- 2025MIMO: A medical vision language model with visual referring multimodal input and pixel grounding multimodal output
- 2024Targeted Visual Prompting for Medical Visual Question Answering