Domain knowledge-driven encoder–decoder for nasopharyngeal carcinoma segmentation

Abstract

Accurate image segmentation is vital for the diagnosis and treatment of nasopharyngeal carcinoma (NPC). Although deep neural networks have shown promising performance in NPC segmentation, they depend on large-scale pixel-level annotation datasets for purely data-driven model training, which poses practical limitations. To address this challenge, this paper explores the domain knowledge, namely the expert knowledge from radiologists, and proposes a domain knowledge-driven encoder–decoder architecture. Specifically, the domain knowledge on image spatial information is formulated as Gaussian mixture distribution and then transformed into an optimal transport-based expert-prior regularization of the encoder, which enhances the model’s ability in capturing discriminative features. To project the encoded features onto pixel space and obtain the segmentation maps, a cross-scale feature refinement module is built in the decoder with theoretical justification, which integrates the domain knowledge that radiologists segment NPC in a gradual refinement process. Experimental results verify the effectiveness of the proposed method for NPC segmentation. Remarkably, despite using only 10% of pixel-level annotation data, the domain knowledge-driven model outperforms recent deep neural networks that use the entire training data.