  We introduce eCLIP, an enhanced version of the CLIP model that integrates
expert annotations in the form of radiologist eye-gaze heatmaps. It tackles key
challenges in contrastive multi-modal medical imaging analysis, notably data
scarcity and the "modality gap" -- a significant disparity between image and
text embeddings that diminishes the quality of representations and hampers
cross-modal interoperability. eCLIP integrates a heatmap processor and
leverages mixup augmentation to efficiently utilize the scarce expert
annotations, thus boosting the model's learning effectiveness. eCLIP is
designed to be generally applicable to any variant of CLIP without requiring
any modifications of the core architecture. Through detailed evaluations across
several tasks, including zero-shot inference, linear probing, cross-modal
retrieval, and Retrieval Augmented Generation (RAG) of radiology reports using
a frozen Large Language Model, eCLIP showcases consistent improvements in
embedding quality. The outcomes reveal enhanced alignment and uniformity,
affirming eCLIP's capability to harness high-quality annotations for enriched
multi-modal analysis in the medical imaging domain.
