Efficient Folded Attention for 3D Medical Image Reconstruction and Segmentation

Recently, 3D medical image reconstruction (MIR) and segmentation (MIS) based on deep neural networks have been developed with promising results, and attention mechanism has been further designed to capture global contextual information for performance enhancement. However, the large size of 3D volume images poses a great computational challenge to traditional attention methods. In this paper, we propose a folded attention (FA) approach to improve the computational efficiency of traditional attention methods on 3D medical images. The main idea is that we apply tensor folding and unfolding operations with four permutations to build four small sub-affinity matrices to approximate the original affinity matrix. Through four consecutive sub-attention modules of FA, each element in the feature tensor can aggregate spatial-channel information from all other elements. Compared to traditional attention methods, with moderate improvement of accuracy, FA can substantially reduce the computational complexity and GPU memory consumption. We demonstrate the superiority of our method on two challenging tasks for 3D MIR and MIS, which are quantitative susceptibility mapping and multiple sclerosis lesion segmentation.Comment: 9 pages, 7 figure

Tetrakis[μ-3-(3-hy­droxy­phen­yl)propenoato]bis­{aqua­(2,2′-bipyridine)­[3-(3-hy­droxy­phen­yl)propenoato]neodymium(III)} 2,2′-bipyridine disolvate dihydrate

The dinuclear title compound, [Nd2(C9H7O3)6(C10H8N2)2]·2C10H8N2·2H2O, was synthesized under hydro­thermal conditions. The centrosymmetric complex consists of two nine-coordinated Nd3+ cations, six 3-hy­droxy­cinnamate anions and two chelating 2,2′-bipyridine mol­ecules. The coordination geometry around the cations can be best described as distorted tricapped trigonal-prismatic. The carboxyl­ate groups show different coordination and bridging modes. Two of them chelate to one Nd3+ cation, two bridge the two cations in a bis-monodentate fashion, and two chelate to one and bridge monodentately to the symmetry-related Nd3+ cation. The dinuclear mol­ecule is surrounded by two 2,2′-bipyridine solvent and two water mol­ecules. Extensive O—H⋯O and O—H⋯N hydrogen-bonding inter­actions between the components lead to the formation of a three-dimensional network