MRIQT: Physics-Aware Diffusion Model for Image Quality Transfer in Neonatal Ultra-Low-Field MRI

TL;DR

MRIQT is a physics-aware diffusion model that enhances ultra-low-field neonatal MRI images to high-quality images, improving diagnostic reliability and surpassing existing methods in image fidelity and clinical assessment.

Contribution

The paper introduces MRIQT, a novel diffusion-based framework that simulates realistic uLF-MRI degradation and achieves superior image quality transfer to high-field MRI, with validated clinical relevance.

Findings

Outperforms GAN and CNN baselines in PSNR by 15.3%

Physicians rated 85% of outputs as good quality

Achieves 1.78% improvement over the state of the art

Abstract

Portable ultra-low-field MRI (uLF-MRI, 0.064 T) offers accessible neuroimaging for neonatal care but suffers from low signal-to-noise ratio and poor diagnostic quality compared to high-field (HF) MRI. We propose MRIQT, a 3D conditional diffusion framework for image quality transfer (IQT) from uLF to HF MRI. MRIQT combines realistic K-space degradation for physics-consistent uLF simulation, v-prediction with classifier-free guidance for stable image-to-image generation, and an SNR-weighted 3D perceptual loss for anatomical fidelity. The model denoises from a noised uLF input conditioned on the same scan, leveraging volumetric attention-UNet architecture for structure-preserving translation. Trained on a neonatal cohort with diverse pathologies, MRIQT surpasses recent GAN and CNN baselines in PSNR 15.3% with 1.78% over the state of the art, while physicians rated 85% of its outputs as good quality with clear pathology present. MRIQT enables high-fidelity, diffusion-based enhancement of portable ultra-low-field (uLF) MRI for deliable neonatal brain assessment.