融合分区注意力UNet模型用于分割MRI中的膝关节软骨

目的 构建融合分区注意力的UNet(PA-UNet)模型,观察其分割MRI中的膝关节软骨的价值。方法 对来源于Osteoarthritis Initiative-Zuse Institute Berlin数据集的膝关节MRI进行切片及预处理,以UNet为骨干网络构建基于分区注意力机制的PA-UNet模型,通过主、客观评价比较该模型与其他模型分割股骨软骨及胫骨软骨的效果;分别以基于UNet、基于SE(第2~4层)的UNet(UNet+SE)、+UNet、++UNet、+++UNet、+UNet+、++UNet++及PA-UNet模型的消融实验观察各模型分割膝关节软骨的效果。结果 PA-UNet可准确分割低难度、中等难度及困难样本中的股骨及胫骨软骨,其分割细小结构效果优于SegNet、UNet及DeepLabv3+模型;其分割股骨软骨及胫骨软骨的戴斯相似系数(DSC)及交并比均高于、而豪斯多夫距离均低于UNet、DeepLabv3+、SA-UNet、RA UNet及SegNet模型。以PA-UNet模型分割股骨软骨及胫骨软骨的DSC分别为88.97%及82.72%,均高于UNet、UNet+SE、+UNet、++UNet、+++UNet、+UNet+及++UNet++模型。结论 PA-UNet可完整分割MRI中的膝关节软骨,尤其对细小结构的分割效果良好。

UNet fusing patch attention for segmenting knee cartilage on MRI

Objective To construct a UNet fusing patch attention (PA-UNet) model, and to observe its value for segmenting knee cartilage on MRI. Methods Slice and preprocessing were performed on knee MRI selected from Osteoarthritis Initiative-Zuse Institute Berlin dataset. Taken UNet as the backbone network, a PA-UNet model was constructed based on patch attention mechanism. The effect of PA-UNet model and other models for segmenting both femoral cartilage and tibial cartilage were compared by subjective and objective evaluations. Ablation experiments based on UNet, UNet based on SE with layers 2—4 (UNet+SE), +UNet, ++UNet, +++UNet, +U-Net+, ++U-Net++ and PA-UNet models were performed to observe the effect of models for segmenting knee cartilage. Results PA-UNet could accurately segment femoral and tibial cartilage in all simple, medium and difficult samples, which had better segmenting effect on small structures than SegNet, UNet and DeepLabv3+ models. The Dice similarity coefficient (DSC) and intersection over union of PA-UNet model for segmenting femoral and tibial cartilage were both higher, while Hausdorff distance of PA-UNet model was lower than those of UNet, DeepLabv3+, SA-UNet, RA UNet and SegNet models. DSC of PA-UNet model for segmenting femoral cartilage and tibial cartilage was 88.97% and 82.72%, respectively, both higher than those of UNet, UNet+SE, +UNet, ++UNet, ++UNet, +UNet+ and ++UNet++ models. Conclusion PA-UNet could segment knee cartilage completely on MRI, especially for small structures.