Boosting Medical Image Synthesis via Registration-guided Consistency and Disentanglement Learning
Chuanpu Li, Zeli Chen, Yiwen Zhang, Liming Zhong, Wei Yang
TL;DR
This work tackles misalignment noise in medical image synthesis by integrating a registration-guided consistency framework with an anatomy consistency disentanglement synthetic module. It introduces a registration module (deformation generator $R_{\Phi}$ and resampler $R_S$) paired with an alignment loss $L_{align}$ to enforce geometry preservation across synthesis before and after applying the same deformation field, and an ACDS module that disentangles anatomical content from modality styles using dedicated encoders and generators, guided by adversarial, self-reconstruction, cycle-consistency, and anatomy-consistency losses. Experimental results on an in-house abdominal CECT-CT dataset and the SynthRAD2023 pelvic MR-CT dataset demonstrate superior quantitative performance (MAE, PSNR, SSIM) and clearer anatomical boundaries, with ablations confirming the contributions of both registration-guided consistency and ACDS. Overall, the approach provides a practical, geometry-preserving framework for robust cross-modality medical image synthesis, reducing misalignment artifacts and improving structural fidelity for clinical tasks such as MR-to-CT and CECT-to-CT synthesis.
Abstract
Medical image synthesis remains challenging due to misalignment noise during training. Existing methods have attempted to address this challenge by incorporating a registration-guided module. However, these methods tend to overlook the task-specific constraints on the synthetic and registration modules, which may cause the synthetic module to still generate spatially aligned images with misaligned target images during training, regardless of the registration module's function. Therefore, this paper proposes registration-guided consistency and incorporates disentanglement learning for medical image synthesis. The proposed registration-guided consistency architecture fosters task-specificity within the synthetic and registration modules by applying identical deformation fields before and after synthesis, while enforcing output consistency through an alignment loss. Moreover, the synthetic module is designed to possess the capability of disentangling anatomical structures and specific styles across various modalities. An anatomy consistency loss is introduced to further compel the synthetic module to preserve geometrical integrity within latent spaces. Experiments conducted on both an in-house abdominal CECT-CT dataset and a publicly available pelvic MR-CT dataset have demonstrated the superiority of the proposed method.
