HU-based Foreground Masking for 3D Medical Masked Image Modeling
This work addresses the problem of inefficient representation learning in 3D medical image segmentation for researchers and practitioners, offering a domain-specific incremental improvement.
The paper tackled the limitation of random masking in 3D medical image computing by introducing an HU-based Foreground Masking strategy, which improved segmentation quality and Dice scores across five datasets, with results such as 92.43% on Flare22.
While Masked Image Modeling (MIM) has revolutionized fields of computer vision, its adoption in 3D medical image computing has been limited by the use of random masking, which overlooks the density of anatomical objects. To address this limitation, we enhance the pretext task with a simple yet effective masking strategy. Leveraging Hounsfield Unit (HU) measurements, we implement an HU-based Foreground Masking, which focuses on the intensity distribution of visceral organs and excludes non-tissue regions, such as air and fluid, that lack diagnostically meaningful features. Extensive experiments on five public 3D medical imaging datasets demonstrate that our masking consistently improves performance, both in quality of segmentation and Dice score (BTCV:~84.64\%, Flare22:~92.43\%, MM-WHS:~90.67\%, Amos22:~88.64\%, BraTS:~78.55\%). These results underscore the importance of domain-centric MIM and suggest a promising direction for representation learning in medical image segmentation. Implementation is available at github.com/AISeedHub/SubFore/.