Ultrasound is one of the most commonly used imaging tools in prostate biopsy and brachytherapy. However, due to issues such as blurred image boundaries, similar intensity distributions, and noise, accurate segmentation of the prostate gland has been challenged. We propose a multi-scale dense connectivity hybrid dilated convolutional U-Net (MDDU-Net) network model segmentation of 2D prostate ultrasound images to improve the segmentation accuracy. Our proposed hybrid dilated convolution (HDC) module consists of standard and dilated convolution, which can expand the receptive field of the network, focus on global information, capture more features, and improve the learning ability of the model. Introducing dense connectivity (Dense) maximizes the flow of information between layers, retains more details, and helps mitigate gradient vanishing. The output features of each convolution layer in the bottleneck and decoder are fused using a multi-scale fusion block (MSFB) to obtain a feature map with richer semantic and detailed information. A dense skip connection provides more raw information to the decoder. To verify the superiority of our proposed method, we performed a 5-fold cross-validation, quantitatively analyzed it using five commonly used medical image evaluation metrics, and compared it with several state-of-the-art segmentation methods. The results show that our method performs better in prostate ultrasound image segmentation and can achieve more accurate prostate segmentation.
Read full abstract