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author Datta, Suvrankar
Buchireddygari, Divya
Kaza, Lakshmi Vennela Chowdary
Bhalke, Mrudula
Singh, Kautik
Pandey, Ayush
Vasipalli, Sonit Sai
Karnwal, Upasana
Bhatti, Hakikat Bir Singh
Maroo, Bhavya Ratan
Hebbar, Sanjana
Joseph, Rahul
Kaur, Gurkawal
Singh, Devyani
V, Akhil
Prasad, Dheeksha Devasya Shama
Mahajan, Nishtha
Arisha, Ayinaparthi
Vanagundi, Rajesh
Nandy, Reet
Vuthoo, Kartik
Rajvanshi, Snigdhaa
Kondaveeti, Nikhileswar
Gunjal, Suyash
Jain, Rishabh
Jain, Rajat
Agrawal, Anurag
author_facet Datta, Suvrankar
Buchireddygari, Divya
Kaza, Lakshmi Vennela Chowdary
Bhalke, Mrudula
Singh, Kautik
Pandey, Ayush
Vasipalli, Sonit Sai
Karnwal, Upasana
Bhatti, Hakikat Bir Singh
Maroo, Bhavya Ratan
Hebbar, Sanjana
Joseph, Rahul
Kaur, Gurkawal
Singh, Devyani
V, Akhil
Prasad, Dheeksha Devasya Shama
Mahajan, Nishtha
Arisha, Ayinaparthi
Vanagundi, Rajesh
Nandy, Reet
Vuthoo, Kartik
Rajvanshi, Snigdhaa
Kondaveeti, Nikhileswar
Gunjal, Suyash
Jain, Rishabh
Jain, Rajat
Agrawal, Anurag
contents Generalist multimodal AI systems such as large language models (LLMs) and vision language models (VLMs) are increasingly accessed by clinicians and patients alike for medical image interpretation through widely available consumer-facing chatbots. Most evaluations claiming expert level performance are on public datasets containing common pathologies. Rigorous evaluation of frontier models on difficult diagnostic cases remains limited. We developed a pilot benchmark of 50 expert-level "spot diagnosis" cases across multiple imaging modalities to evaluate the performance of frontier AI models against board-certified radiologists and radiology trainees. To mirror real-world usage, the reasoning modes of five popular frontier AI models were tested through their native web interfaces, viz. OpenAI o3, OpenAI GPT-5, Gemini 2.5 Pro, Grok-4, and Claude Opus 4.1. Accuracy was scored by blinded experts, and reproducibility was assessed across three independent runs. GPT-5 was additionally evaluated across various reasoning modes. Reasoning quality errors were assessed and a taxonomy of visual reasoning errors was defined. Board-certified radiologists achieved the highest diagnostic accuracy (83%), outperforming trainees (45%) and all AI models (best performance shown by GPT-5: 30%). Reliability was substantial for GPT-5 and o3, moderate for Gemini 2.5 Pro and Grok-4, and poor for Claude Opus 4.1. These findings demonstrate that advanced frontier models fall far short of radiologists in challenging diagnostic cases. Our benchmark highlights the present limitations of generalist AI in medical imaging and cautions against unsupervised clinical use. We also provide a qualitative analysis of reasoning traces and propose a practical taxonomy of visual reasoning errors by AI models for better understanding their failure modes, informing evaluation standards and guiding more robust model development.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25559
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Radiology's Last Exam (RadLE): Benchmarking Frontier Multimodal AI Against Human Experts and a Taxonomy of Visual Reasoning Errors in Radiology
Datta, Suvrankar
Buchireddygari, Divya
Kaza, Lakshmi Vennela Chowdary
Bhalke, Mrudula
Singh, Kautik
Pandey, Ayush
Vasipalli, Sonit Sai
Karnwal, Upasana
Bhatti, Hakikat Bir Singh
Maroo, Bhavya Ratan
Hebbar, Sanjana
Joseph, Rahul
Kaur, Gurkawal
Singh, Devyani
V, Akhil
Prasad, Dheeksha Devasya Shama
Mahajan, Nishtha
Arisha, Ayinaparthi
Vanagundi, Rajesh
Nandy, Reet
Vuthoo, Kartik
Rajvanshi, Snigdhaa
Kondaveeti, Nikhileswar
Gunjal, Suyash
Jain, Rishabh
Jain, Rajat
Agrawal, Anurag
Artificial Intelligence
Machine Learning
Generalist multimodal AI systems such as large language models (LLMs) and vision language models (VLMs) are increasingly accessed by clinicians and patients alike for medical image interpretation through widely available consumer-facing chatbots. Most evaluations claiming expert level performance are on public datasets containing common pathologies. Rigorous evaluation of frontier models on difficult diagnostic cases remains limited. We developed a pilot benchmark of 50 expert-level "spot diagnosis" cases across multiple imaging modalities to evaluate the performance of frontier AI models against board-certified radiologists and radiology trainees. To mirror real-world usage, the reasoning modes of five popular frontier AI models were tested through their native web interfaces, viz. OpenAI o3, OpenAI GPT-5, Gemini 2.5 Pro, Grok-4, and Claude Opus 4.1. Accuracy was scored by blinded experts, and reproducibility was assessed across three independent runs. GPT-5 was additionally evaluated across various reasoning modes. Reasoning quality errors were assessed and a taxonomy of visual reasoning errors was defined. Board-certified radiologists achieved the highest diagnostic accuracy (83%), outperforming trainees (45%) and all AI models (best performance shown by GPT-5: 30%). Reliability was substantial for GPT-5 and o3, moderate for Gemini 2.5 Pro and Grok-4, and poor for Claude Opus 4.1. These findings demonstrate that advanced frontier models fall far short of radiologists in challenging diagnostic cases. Our benchmark highlights the present limitations of generalist AI in medical imaging and cautions against unsupervised clinical use. We also provide a qualitative analysis of reasoning traces and propose a practical taxonomy of visual reasoning errors by AI models for better understanding their failure modes, informing evaluation standards and guiding more robust model development.
title Radiology's Last Exam (RadLE): Benchmarking Frontier Multimodal AI Against Human Experts and a Taxonomy of Visual Reasoning Errors in Radiology
topic Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2509.25559