Methods, systems, and computer readable media for unpaired volumetric harmonization of multi-site brain magnetic resonance imaging with conditional latent diffusion

A system for unpaired volumetric harmonization of multi-site brain magnetic resonance images (MRIs) with conditional latent diffusion, the system comprising:

• a computing platform including at least one processor and a memory;
• a feature extraction module implemented by the at least one processor for receiving, as inputs, unpaired three-dimensional (3D) MRIs from a source domain and a target domain, wherein the source domain and the target domain are associated with different MRI scanning sites, and extracting, features from the MRIs to generate source latent feature maps and target latent feature maps from the MRIs;
• a latent map fusion module implemented by the at least one processor for receiving, as inputs, the source latent feature maps and the target latent feature maps and generating coarsely aligned source-to-target feature maps;
• a conditional latent diffusion model implemented by the at least one processor for receiving, as inputs, the coarsely aligned source-to-target feature maps and the target latent feature maps, iteratively adding noise to the coarsely aligned source-to-target feature maps and iteratively denoising the coarsely aligned source-to-target feature maps to generate reconstructed source feature maps with content features from the source feature maps and style from the target domain;
• and
• a 3D decoder implemented by the at least one processor for receiving, as inputs, the reconstructed source feature maps and generating, from the reconstructed source feature maps, harmonized MRIs in the style of the target domain.

A non-transitory computer readable medium having stored thereon executable instructions that when executed by a processor of a computer control the computer to perform steps comprising:

• during an inference stage:
• receiving, as inputs to a feature extraction module, unpaired three-dimensional (3D) magnetic resonance images (MRIs) from a source domain and a target domain, wherein the source domain and the target domain are associated with different MRI scanning sites, and extracting, by the feature extraction module, features from the MRIs to generate source latent feature maps and target latent feature maps from the MRIs;
• providing the source latent feature maps and the target latent feature maps to a latent map fusion module that generates coarsely aligned source-to-target feature maps;
• providing the coarsely aligned source-to-target feature maps and the target latent feature maps to a conditional latent diffusion model that iteratively adds noise to the coarsely aligned source-to-target feature maps then iteratively denoises the coarsely aligned source-to-target feature maps to generate reconstructed source feature maps with content features from the source feature maps and style from the target domain;
• and
• providing the reconstructed source feature maps to a 3D decoder, which generates, from the reconstructed source feature maps, harmonized MRIs in the style of the target domain.