Diffusion models have enabled remarkably high-quality medical image generation, which can help mitigate the expenses of acquiring and annotating new images by supplementing small or imbalanced datasets, along with other applications. However, these are hampered by the challenge of enforcing global anatomical realism in generated images. To this end, we propose a diffusion model for anatomically-controlled medical image generation. Our model follows a multi-class anatomical segmentation mask at each sampling step and incorporates a \textit{random mask ablation} training algorithm, to enable conditioning on a selected combination of anatomical constraints while allowing flexibility in other anatomical areas. This also improves the network's learning of anatomical realism for the completely unconditional (unconstrained generation) case. Comparative evaluation on breast MRI and abdominal/neck-to-pelvis CT datasets demonstrates superior anatomical realism and input mask faithfulness over state-of-the-art models. We also offer an accessible codebase and release a dataset of generated paired breast MRIs. Our approach facilitates diverse applications, including pre-registered image generation, counterfactual scenarios, and others.

通过扩充小规模或不平衡数据集来生成高质量的影像，本研究提出了一种扩散模型来实现解剖结构控制的医学影像生成，有别于现有模型，该模型在每个采样步骤中遵循多类解剖学分割掩模，并采用随机掩模消融算法来实现对所选解剖约束的条件控制。在乳腺磁共振成像和腹部/颈至骨盆CT数据集上进行比较评估，验证了本模型对于解剖结构真实性和掩模准确性的优越性。此外，我们提供易于使用的代码库并发布了一个生成的成对乳腺磁共振成像数据集，该方法具有多种应用，包括预注册影像生成和反事实情境分析等。

基于分割引导扩散模型的可控解剖学医学影像生成