Phase-correcting non-local means filtering for diffusion-weighted imaging of the spinal cord

buir.contributor.authorKafalı, Sevgi Gökçe
buir.contributor.authorÇukur, Tolga
buir.contributor.authorSarıtaş, Emine Ülkü
dc.citation.epage1035en_US
dc.citation.issueNumber3en_US
dc.citation.spage1020en_US
dc.citation.volumeNumber80en_US
dc.contributor.authorKafalı, Sevgi Gökçeen_US
dc.contributor.authorÇukur, Tolgaen_US
dc.contributor.authorSarıtaş, Emine Ülküen_US
dc.date.accessioned2019-02-21T16:02:27Z
dc.date.available2019-02-21T16:02:27Z
dc.date.issued2018en_US
dc.departmentDepartment of Electrical and Electronics Engineeringen_US
dc.departmentNational Magnetic Resonance Research Center (UMRAM)en_US
dc.departmentInterdisciplinary Program in Neuroscience (NEUROSCIENCE)en_US
dc.departmentAysel Sabuncu Brain Research Center (BAM)en_US
dc.description.abstractPurpose: DWI suffers from low SNR when compared to anatomical MRI. To maintain reasonable SNR at relatively high spatial resolution, multiple acquisitions must be averaged. However, subject motion or involuntary physiological motion during diffusion-sensitizing gradients cause phase offsets among acquisitions. When the motion is localized to a small region, these phase offsets become particularly problematic. Complex averaging of acquisitions lead to cancellations from these phase offsets, whereas magnitude averaging results in noise amplification. Here, we propose an improved reconstruction for multi-acquisition DWI that effectively corrects for phase offsets while reducing noise. Theory and Methods: Each acquisition is processed with a refocusing reconstruction for global phase correction and a partial k-space reconstruction via projection-onto-convex-sets (POCS). The proposed reconstruction then embodies a new phase-correcting non-local means (PC-NLM) filter. PC-NLM is performed on the complex-valued outputs of the POCS algorithm aggregated across acquisitions. The PC-NLM filter leverages the shared structure among multiple acquisitions to simultaneously alleviate nuisance factors including phase offsets and noise. Results: Extensive simulations and in vivo DWI experiments of the cervical spinal cord are presented. The results demonstrate that the proposed reconstruction improves image quality by mitigating signal loss because of phase offsets and reducing noise. Importantly, these improvements are achieved while preserving the accuracy of apparent diffusion coefficient maps. Conclusion: An improved reconstruction incorporating a PC-NLM filter for multi-acquisition DWI is presented. This reconstruction can be particularly beneficial for high-resolution or high-b-value DWI acquisitions that suffer from low SNR and phase offsets from local motion.
dc.description.provenanceMade available in DSpace on 2019-02-21T16:02:27Z (GMT). No. of bitstreams: 1 Bilkent-research-paper.pdf: 222869 bytes, checksum: 842af2b9bd649e7f548593affdbafbb3 (MD5) Previous issue date: 2018en
dc.description.sponsorshipThis work was supported by the European Commission through an FP7 Marie Curie Career Integration Grant (PCIG13GA618834, PCIG13GA618101), by a European Molecular Biology Organization Installation Grant (IG 3028), by the Turkish Academy of Sciences through TUBA-GEBIP 2015 program, and by the BAGEP Award of the Science Academy
dc.embargo.release2019-05-21en_US
dc.identifier.doi10.1002/mrm.27105
dc.identifier.eissn1522-2594
dc.identifier.issn0740-3194
dc.identifier.urihttp://hdl.handle.net/11693/50006
dc.language.isoEnglish
dc.publisherJohn Wiley
dc.relation.isversionofhttps://doi.org/10.1002/mrm.27105
dc.relation.projectPCIG13GA618101, PCIG13GA618834 - European Molecular Biology Organization, EMBO - European Commission, EC: FP7 - Türkiye Bilimler Akademisi, TÜBA - Bilim Akademisi - European Molecular Biology Organization, EMBO: IG 3028 - PCIG13GA618101, PCIG13GA618834 - European Commission, EC - Türkiye Bilimler Akademisi, TÜBA - Bilim Akademisi
dc.source.titleMagnetic Resonance in Medicineen_US
dc.subjectDenoisingen_US
dc.subjectDiffusion weighted imagingen_US
dc.subjectMotionen_US
dc.subjectNon-local meansen_US
dc.subjectPhase correctionen_US
dc.subjectSpinal corden_US
dc.titlePhase-correcting non-local means filtering for diffusion-weighted imaging of the spinal corden_US
dc.typeArticleen_US

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