Synchronous Image-Label Diffusion Probability Model With Application to Stroke Lesion Segmentation on Non-Contrast CT.

The stroke lesion volume is a key radiologic measurement for assessing the prognosis of acute ischemic stroke (AIS) patients, which is challenging to be automatically measured on noncontrast CT (NCCT) scans. Recent diffusion probabilistic models (DPMs) in the domain of image generation have shown potentials of being used for lesion volume segmentation on medical images. In this article, a novel synchronous image-label diffusion probability model (SDPM) is proposed for stroke lesion segmentation on NCCT using a dual-Markov diffusion process with shared noise. The proposed SDPM is fully based on a generative latent variable model (LVM), offering a probabilistic elaboration from stem to stem. To fit into our segmentation tasks using the strength from generation models, we develop the architecture of the network where an additional net-stream, parallel with a noise prediction stream, is introduced to obtain the initial label estimates with noise for efficiently inferring the final labels. By optimizing the specified variational boundaries, the trained model can infer the final label estimates given the input images at any scale of time in four different label-inference methods, which gives more flexibility to the proposed SDPM. The proposed model was assessed on three stroke lesion datasets including one public and two private datasets. Compared with several U-Net, transformer, and DPM-based segmentation methods, our proposed SDPM model is able to achieve the state-of-the-art accuracy.