TranSiam: Aggregating multi-modal visual features with locality for medical image segmentation

Automatic segmentation of medical images plays an important role in the diagnosis of diseases. On single-modal data, convolutional neural networks have demonstrated satisfactory performance. However, multi-modal data encompasses a greater amount of information rather than single-modal data. Multi-modal data can be effectively used to improve the segmentation accuracy of regions of interest by analyzing both spatial and temporal information. In this study, we propose a dual-path segmentation model for multi-modal medical images, named TranSiam. Taking into account that there is a significant diversity between the different modalities, TranSiam employs two parallel CNNs to extract the features which are specific to each of the modalities. In our method, two parallel CNNs extract detailed and local information in the low-level layer, and the Transformer layer extracts global information in the high-level layer. Finally, we fuse the features of different modalities via a locality-aware aggregation block (LAA block) to establish the association between different modal features. The LAA block is used to locate the region of interest and suppress the influence of invalid regions on multi-modal feature fusion. TranSiam uses LAA blocks at each layer of the encoder in order to fully fuse multi-modal information at different scales. Extensive experiments on several multi-modal datasets have shown that TranSiam achieves satisfying results.