FocusMAE: Gallbladder Cancer Detection from Ultrasound Videos with Focused Masked Autoencoders
Authors: Soumen Basu, Mayuna Gupta, Chetan Madan, Pankaj Gupta, Chetan Arora

In recent years automated Gallbladder Cancer (GBC) detection has gained the attention of researchers. Current state-of-the-art (SOTA) methodologies relying on ultrasound sonography (US) images exhibit limited generalization emphasizing the need for transformative approaches. We observe that individual US frames may lack sufficient information to capture disease manifestation. This study advocates for a paradigm shift towards video-based GBC detection leveraging the inherent advantages of spatiotemporal representations. Employing the Masked Autoencoder (MAE) for representation learning we address shortcomings in conventional image-based methods. We propose a novel design called FocusMAE to systematically bias the selection of masking tokens from high-information regions fostering a more refined representation of malignancy. Additionally we contribute the most extensive US video dataset for GBC detection. We also note that this is the first study on US video-based GBC detection. We validate the proposed methods on the curated dataset and report a new SOTA accuracy of 96.4% for the GBC detection problem against an accuracy of 84% by current Image-based SOTA - GBCNet and RadFormer and 94.7% by Video-based SOTA - AdaMAE. We further demonstrate the generality of the proposed FocusMAE on a public CT-based Covid detection dataset reporting an improvement in accuracy by 3.3% over current baselines. Project page with source code trained models and data is available at: https://gbc-iitd.github.io/focusmae.