A multi-scale channel attention network with federated learning for magnetic resonance image super-resolution

Magnetic resonance (MR) images are widely used for clinical diagnosis, whereas some surrounding factors always limit the resolution, so under-sampled data is usually generated during imaging. Since high-resolution (HR) MR images contribute to the clinic diagnosis, reconstructing HR MR images from these under-sampled data is pretty important. Recently, deep learning (DL) methods for HR reconstruction of MR images have achieved impressive performance. However, it is difficult to collect enough data for training DL models in practice due to medical data privacy regulations. Fortunately, federated learning (FL) is proposed to eliminate this issue by local/distributed training and encryption. In this paper, we propose a multi-scale channel attention network (MSCAN) for MR image super-resolution (SR) and integrate it into an FL framework named FedAve to make use of data from multiple institutions and avoid privacy risk. Specifically, to utilize multi-scale information in MR images, we introduce a multi-scale feature block (MSFB), in which multi-scale features are extracted and attention among features at different scales is captured to re-weight these multi-scale features. Then, a spatial gradient profile loss is integrated into MSCAN to facilitate the recovery of textures in MR images. Last, we incorporate MSCAN into FedAve to simulate the scenery of collaborated training among multiple institutions. Ablation studies show the effectiveness of the multi-scale features, the multi-scale channel attention, and the texture loss. Comparative experiments with some state-of-the-art (SOTA) methods indicate that the proposed MSCAN is superior to the compared methods and the model with FL has close results to the one trained by centralized data.