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Google-MedGemma Based Abnormality Detection in Musculoskeletal radiographs

Soumyajit Maity, Pranjal Kamboj, Sneha Maity, Rajat Singh, Sankhadeep Chatterjee

TL;DR

Musculoskeletal radiograph abnormality detection is challenged by data diversity, subtle findings, and class imbalance. The paper proposes a MedGemma-based pipeline that leverages a SigLIP medical vision encoder to extract robust image embeddings, followed by a lightweight MLP classifier with selective unfreezing for domain adaptation. Across the MURA benchmark, the approach achieves high accuracy, macro-F1, and AUROC, outperforming conventional CNN- and autoencoder-based baselines and demonstrating efficient transfer learning. This work demonstrates the practicality of medical foundation models for scalable radiograph triage and outlines directions for multimodal integration, uncertainty quantification, and cross-institution validation.

Abstract

This paper proposes a MedGemma-based framework for automatic abnormality detection in musculoskeletal radiographs. Departing from conventional autoencoder and neural network pipelines, the proposed method leverages the MedGemma foundation model, incorporating a SigLIP-derived vision encoder pretrained on diverse medical imaging modalities. Preprocessed X-ray images are encoded into high-dimensional embeddings using the MedGemma vision backbone, which are subsequently passed through a lightweight multilayer perceptron for binary classification. Experimental assessment reveals that the MedGemma-driven classifier exhibits strong performance, exceeding conventional convolutional and autoencoder-based metrics. Additionally, the model leverages MedGemma's transfer learning capabilities, enhancing generalization and optimizing feature engineering. The integration of a modern medical foundation model not only enhances representation learning but also facilitates modular training strategies such as selective encoder block unfreezing for efficient domain adaptation. The findings suggest that MedGemma-powered classification systems can advance clinical radiograph triage by providing scalable and accurate abnormality detection, with potential for broader applications in automated medical image analysis. Keywords: Google MedGemma, MURA, Medical Image, Classification.

Google-MedGemma Based Abnormality Detection in Musculoskeletal radiographs

TL;DR

Musculoskeletal radiograph abnormality detection is challenged by data diversity, subtle findings, and class imbalance. The paper proposes a MedGemma-based pipeline that leverages a SigLIP medical vision encoder to extract robust image embeddings, followed by a lightweight MLP classifier with selective unfreezing for domain adaptation. Across the MURA benchmark, the approach achieves high accuracy, macro-F1, and AUROC, outperforming conventional CNN- and autoencoder-based baselines and demonstrating efficient transfer learning. This work demonstrates the practicality of medical foundation models for scalable radiograph triage and outlines directions for multimodal integration, uncertainty quantification, and cross-institution validation.

Abstract

This paper proposes a MedGemma-based framework for automatic abnormality detection in musculoskeletal radiographs. Departing from conventional autoencoder and neural network pipelines, the proposed method leverages the MedGemma foundation model, incorporating a SigLIP-derived vision encoder pretrained on diverse medical imaging modalities. Preprocessed X-ray images are encoded into high-dimensional embeddings using the MedGemma vision backbone, which are subsequently passed through a lightweight multilayer perceptron for binary classification. Experimental assessment reveals that the MedGemma-driven classifier exhibits strong performance, exceeding conventional convolutional and autoencoder-based metrics. Additionally, the model leverages MedGemma's transfer learning capabilities, enhancing generalization and optimizing feature engineering. The integration of a modern medical foundation model not only enhances representation learning but also facilitates modular training strategies such as selective encoder block unfreezing for efficient domain adaptation. The findings suggest that MedGemma-powered classification systems can advance clinical radiograph triage by providing scalable and accurate abnormality detection, with potential for broader applications in automated medical image analysis. Keywords: Google MedGemma, MURA, Medical Image, Classification.

Paper Structure

This paper contains 10 sections, 7 equations, 3 figures, 2 tables.

Figures (3)

  • Figure 1: Diagram of the proposed MedGemma based classifier.
  • Figure 2: Per-anatomy diagnostic performance of MedGemma-4B-PT across seven anatomical regions and overall.
  • Figure 3: Comparison of overall F1-score and AUROC for head-only fine-tuning and varying depth of encoder block unfreezing