A regularized reconstruction pipeline for high‐definition diffusion MRI in challenging regions incorporating a per‐shot image correction. Issue 4 (5th June 2019)

• Record Type: Journal Article
• Authors: Cousin, Samuel F.; Liberman, Gilad; Solomon, Eddy; Otikovs, Martins; Frydman, Lucio
• Is Part Of: Magnetic resonance in medicine. Volume 82:Issue 4(2019)
• Page Start: 1322
• Page End: 1330
• Publication Date: 2019-06-05
• Subjects: brain DTI -- interleaved acquisitions -- interscan correction -- regularized reconstruction -- spatiotemporal encoding (SPEN); Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.27802
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: Diffusion MRI is of interest for clinical research and diagnosis. Whereas high‐ resolution DWI/DTI is hard to achieve by single‐shot methods, interleaved acquisitions can deliver these if motion and/or folding artefacts are overcome. Thanks to its ability to provide zoomed, folding‐free images, spatially encoded MRI can fulfill these requirements. This is here coupled with a regularized reconstruction and parallel receive methods, to deliver a robust scheme for human DWI/DTI at mm and sub‐mm resolutions. Methods: Each shot along the spatially encoded dimension was reconstructed separately to retrieve per‐shot phase maps. These shots, together with coil sensitivities, were combined with spatially encoded quadratic phase‐encoding matrices associated to each shot, into single global operators. Their originating images were then iteratively computed aided by l1 and l2 regularization methods. When needed, motion‐corrupted shots were discarded and replaced by redundant information arising from parallel imaging. Results: Full‐brain DTI experiments at 1 mm and restricted brain DTIs with 0.75 mm nominal in‐plane resolutions were acquired and reconstructed successfully by the new scheme. These 3 Tesla spetiotemporally encoded results compared favorably with EPI counterparts based on segmented and selective excitation schemes provided with the scanner. Conclusion: A new procedure for achieving high‐definition diffusion‐based MRI was developed and demonstrated.