Macro2Micro: A Rapid and Precise Cross-modal Magnetic Resonance Imaging Synthesis using Multi-scale Structural Brain Similarity

TL;DR

Macro2Micro is a deep learning framework that rapidly and accurately predicts brain microstructure from macrostructure MRI scans using a multi-scale GAN approach, enabling real-time multimodal brain imaging.

Contribution

It introduces a novel multi-scale GAN model with an auxiliary discriminator for cross-modal MRI synthesis, improving accuracy and speed over previous methods.

Findings

Achieved 6.8% higher SSIM in MRI translation

Enabled real-time inference with less than 0.01 seconds per translation

Faithfully preserves brain biological characteristics

Abstract

The human brain is a complex system requiring both macroscopic and microscopic components for comprehensive understanding. However, mapping nonlinear relationships between these scales remains challenging due to technical limitations and the high cost of multimodal Magnetic Resonance Imaging (MRI) acquisition. To address this, we introduce Macro2Micro, a deep learning framework that predicts brain microstructure from macrostructure using a Generative Adversarial Network (GAN). Based on the hypothesis that microscale structural information can be inferred from macroscale structures, Macro2Micro explicitly encodes multiscale brain information into distinct processing branches. To enhance artifact elimination and output quality, we propose a simple yet effective auxiliary discriminator and learning objective. Extensive experiments demonstrated that Macro2Micro faithfully translates T1-weighted MRIs into corresponding Fractional Anisotropy (FA) images, achieving a 6.8\% improvement in the Structural Similarity Index Measure (SSIM) compared to previous methods, while retaining the individual biological characteristics of the brain. With an inference time of less than 0.01 seconds per MR modality translation, Macro2Micro introduces the potential for real-time multimodal rendering in medical and research applications. The code will be made available upon acceptance.