Summary
Doctors often need to look at medical images like chest x-rays and read patient notes together to make a diagnosis, but standard computer programs can’t easily combine these two data types. The authors created OmniMed-FL, a system allowing many hospitals to jointly train diagnostic models without sharing sensitive patient data directly, respecting privacy laws. They tested different ways to combine image and text data and handle missing information using simulated data, showing that combining both types improves diagnosis classification compared to using either alone. This work shows promising methods for secure and effective joint medical data analysis across institutions.
What this means in practice
- •For hospital data teams: Train clinical diagnosis models collaboratively across hospitals without sharing raw patient data, combining medical images with textual notes securely.
- •For radiology software developers: Develop diagnostic tools that integrate visual and textual patient information under privacy constraints using federated multimodal learning techniques.
Tested on simulated data.
Abstract
Simultaneous assessment of medical imaging and patient records is often required in clinical diagnosis. However, standard machine learning algorithms cannot analyze these data types together. Meanwhile, compliance with HIPAA and GDPR can constrain centralized aggregation of sensitive patient data. This leaves a crucial void of secure fusion of visual and textual context across distant networks. Thus, we present OmniMed-FL, a controlled systems study of multimodal federated learning for five-class clinical condition classification (Normal, Pneumonia, COVID-19, Pleural Effusion, Cardiomegaly). Our proxy corpus pairs 3,000 public chest radiographs with 3,000 class-conditioned synthetic notes, matched by class, not by patient. The framework benchmarks eight fusion strategies, three initializations, four missing-text imputation rules, and matched federated baselines under non-IID Dirichlet partitioning across 3 to 20 hospital clients. As all notes are synthetic and pairing is not patient-level, these are descriptive proxy comparisons, not estimates of diagnostic performance or deployment readiness. Within those limits with clients ($K=5$) and severe skew ($α=0.1$), local-only training achieves a macro-F1 score of 0.297, FedAvg achieves $0.662\pm0.074$, FedProx $0.737\pm0.085$, a matched FedMME-style one-shot ensemble $0.647\pm0.080$, and our SCAFFOLD-AdamW adaptation $0.070\pm0.015$, the 0.075 FedProx-FedAvg gap falling inside the wider of the two two-seed standard deviations. Over a $4\times3$ grid, label skew costs up to 0.27 F1 whereas a near-sevenfold client increase costs at most 0.10, while bidirectional volume grows linearly to 183.5 GiB at $K=20$. Multimodal fusion leads on both corpora, scoring 0.956 against 0.934 for text and 0.664 for images on the synthetic corpus and 0.906 against 0.880 and 0.737 on the radiograph corpus, for $2.3\times$ the model state of text alone.