aceCan General-purpose Multimodal AI Reliably Measure Cobb Angles? A Head-to-head Diagnostic Agreement Study of GPT-5.1 and Gemini 3.1 Pro in Adolescent Idiopathic Scoliosis
General-purpose multimodal artificial intelligence (AI) models can interpret radiographs through natural-language prompts, but their quantitative agreement and anatomical traceability in adolescent idiopathic scoliosis remain uncertain. We compared GPT-5.1 and Gemini 3.1 Pro with a joint expert-consensus reference on 125 anonymized standing coronal whole-spine radiographs. Each model evaluated each image once in an independent chat session using the same standardized prompt; only the first response was retained.…
Neither GPT-5.1 nor Gemini 3.1 Pro agreed closely enough with expert consensus on case-level Cobb angles and end-vertebra identification to measure scoliosis curves autonomously.
Results are relative to expert consensus and do not establish absolute measurement accuracy or model repeatability, since each image was assessed once per model in a single session.
Evidence
- Peer-reviewedJournal of Imaging Informatics in Medicine2026-10-13
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Truvace Impact Record TRV-2026-1361, v1: “Can General-purpose Multimodal AI Reliably Measure Cobb Angles? A Head-to-head Diagnostic Agreement Study of GPT-5.1 and Gemini 3.1 Pro in Adolescent Idiopathic Scoliosis.” Truvace, 2026-10-14. /record/TRV-2026-1361 (accessed at citation time). sha256 d6bd4756bae89db4…
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