{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/estimating-absolute-phase-maps-using-espirit","title":"Estimating Absolute-Phase Maps Using ESPIRiT and Virtual Conjugate Coils","arxiv_id":"1509.03557","date":"2015-07-17","proceeding":null,"authors":["Martin Uecker","Michael Lustig"],"abstract":"Purpose: To develop an ESPIRiT-based method to estimate coil sensitivities\nwith image phase as a building block for efficient and robust image\nreconstruction with phase constraints. Theory and Methods: ESPIRiT is a new\nframework for calibration of the coil sensitivities and reconstruction in\nparallel Magnetic Resonance Imaging (MRI). Applying ESPIRiT to a combined set\nof physical and virtual conjugate coils (VCC-ESPIRiT) implicitly exploits\nconjugate symmetry in k-space similar to VCC-GRAPPA. Based on this method, a\nnew post-processing step is proposed for the explicit computation of coil\nsensitivities that include the absolute phase of the image. The accuracy of the\ncomputed maps is directly validated using a test based on projection onto fully\nsampled coil images and also indirectly in phase-constrained parallel-imaging\nreconstructions. Results: The proposed method can estimate accurate\nsensitivities which include low-resolution image phase. In case of\nhigh-frequency phase variations VCC-ESPIRiT yields an additional set of maps\nthat indicates the existence of a high-frequency phase component. Taking this\nadditional set of maps into account can improve the robustness of\nphase-constrained parallel imaging. Conclusion: The extended VCC-ESPIRiT is a\nuseful tool for phase-constrained imaging.","url_abs":"http://arxiv.org/abs/1509.03557v2","url_pdf":"http://arxiv.org/pdf/1509.03557v2.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"abstracts"},"code_links":[{"paper_slug":"estimating-absolute-phase-maps-using-espirit","repo_url":"https://github.com/uecker/vcc-espirit","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"none","reach":null}],"tasks":[{"task_slug":"image-reconstruction","task_name":"Image Reconstruction"}],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}