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Abstract #4508

Accelerating MRI with Spiral Trajectory Optimization and Reconstruction using Diffusion Models

Trevor J Chan1, Jessie Dong1, Nabo Yu2, Hee Kwon Song3, and Chamith S Rajapakse3
1Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 2University of Pennsylvania, Philadelphia, PA, United States, 3Radiology, University of Pennsylvania, Philadelphia, PA, United States

Synopsis

Keywords: AI/ML Image Reconstruction, Machine Learning/Artificial Intelligence

Motivation: Deep learning methods for accelerated MRI achieve state-of-the-art results but largely ignore additional speedups possible with noncartesian sampling trajectories.

Goal(s): To create a generative diffusion model-based reconstruction algorithm for multi-coil undersampled spiral MRI.

Approach: We train a conditional diffusion model and use frequency-based guidance to ensure consistency between images and measurements.

Results: Evaluated on retrospective data, we show high quality (SSIM > 0.87) in reconstructed images with ultrafast scan times (0.02 seconds for a 2D image). We use this algorithm to identify a set of optimal variable-density spiral trajectories and show large improvements in image quality compared to conventional nufft reconstruction.

Impact: We apply diffusion models to the task of non-cartesian reconstruction. Combining efficient spiral sampling trajectories, multicoil imaging, and deep learning reconstruction enables drastically accelerated imaging. Potential applications of this technology include real-time 3D imaging.

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Keywords