Medical image pretraining stops reading only reports: DICOM acquisition fields enter contrastive learning, lifting zero-shot CT macro-AUROC by 1.41 points
Medical vision-language pretraining learns from paired images and radiology reports, but scanner and acquisition-protocol differences can impair transfer. Meta-CLIP uses structured acquisition information in DICOM headers as a training-time prior: a kernel over numerical and categorical fields defines a bounded pairwise margin that reweights cross-modal negatives during pretraining, while inference keeps the standard dual-encoder architecture and needs no metadata. On CT-RATE it improves macro-AUROC over CT-CLIP by 1.41 points, with a 95% paired bootstrap interval of 0.96 to 1.85 points, and reaches the highest macro-AUROC on four of five chest radiography benchmarks.