Hybrid algorithms for SAR matrix compression and the impact of post-processing on SAR calculation complexity.
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| Názov: | Hybrid algorithms for SAR matrix compression and the impact of post-processing on SAR calculation complexity. |
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| Autori: | Orzada S; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany., Fiedler TM; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany., Ladd ME; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.; Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany.; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.; Faculty of Medicine, Heidelberg University, Heidelberg, Germany. |
| Zdroj: | Magnetic resonance in medicine [Magn Reson Med] 2024 Dec; Vol. 92 (6), pp. 2696-2706. Date of Electronic Publication: 2024 Jul 26. |
| Spôsob vydávania: | Journal Article |
| Jazyk: | English |
| Informácie o časopise: | Publisher: Wiley Country of Publication: United States NLM ID: 8505245 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1522-2594 (Electronic) Linking ISSN: 07403194 NLM ISO Abbreviation: Magn Reson Med Subsets: MEDLINE |
| Imprint Name(s): | Publication: 1999- : New York, NY : Wiley Original Publication: San Diego : Academic Press, |
| Výrazy zo slovníka MeSH: | Algorithms* , Magnetic Resonance Imaging*/methods , Data Compression*/methods, Humans ; Phantoms, Imaging ; Image Processing, Computer-Assisted/methods ; Reproducibility of Results ; Brain/diagnostic imaging |
| Abstrakt: | Purpose: This study proposes faster virtual observation point (VOP) compression as well as post-processing algorithms for specific absorption rate (SAR) matrix compression. Furthermore, it shows the relation between the number of channels and the computational burden for VOP-based SAR calculation. Methods: The proposed new algorithms combine the respective benefits of two different criteria for determining upper boundedness of SAR matrices by the VOPs. Comparisons of the old and new algorithms are performed for head coil arrays with various channel counts. The new post-processing algorithm is used to post-process the VOP sets of nine arrays, and the number of VOPs for a fixed median relative overestimation is compared. Results: The new algorithms are faster than the old algorithms by a factor of two to more than 10. The compression efficiency (number of VOPs relative to initial number of SAR matrices) is identical. For a fixed median relative overestimation, the number of VOPs increases logarithmically with the number of RF coil channels when post-processing is applied. Conclusion: The new algorithms are much faster than previous algorithms. Post-processing is very beneficial for online SAR supervision of MRI systems with high channel counts, since for a given number of VOPs the relative SAR overestimation can be lowered. (© 2024 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.) |
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| Grant Information: | 101078393 / MRItwins HORIZON EUROPE Framework Programme |
| Contributed Indexing: | Keywords: MRI; SAR; VOP compression; VOPs; local; specific absorption rate; virtual observation points |
| Entry Date(s): | Date Created: 20240726 Date Completed: 20240927 Latest Revision: 20240927 |
| Update Code: | 20250114 |
| DOI: | 10.1002/mrm.30235 |
| PMID: | 39056341 |
| Databáza: | MEDLINE |
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Nájsť tento článok vo Web of Science | Abstrakt: | Purpose: This study proposes faster virtual observation point (VOP) compression as well as post-processing algorithms for specific absorption rate (SAR) matrix compression. Furthermore, it shows the relation between the number of channels and the computational burden for VOP-based SAR calculation.<br />Methods: The proposed new algorithms combine the respective benefits of two different criteria for determining upper boundedness of SAR matrices by the VOPs. Comparisons of the old and new algorithms are performed for head coil arrays with various channel counts. The new post-processing algorithm is used to post-process the VOP sets of nine arrays, and the number of VOPs for a fixed median relative overestimation is compared.<br />Results: The new algorithms are faster than the old algorithms by a factor of two to more than 10. The compression efficiency (number of VOPs relative to initial number of SAR matrices) is identical. For a fixed median relative overestimation, the number of VOPs increases logarithmically with the number of RF coil channels when post-processing is applied.<br />Conclusion: The new algorithms are much faster than previous algorithms. Post-processing is very beneficial for online SAR supervision of MRI systems with high channel counts, since for a given number of VOPs the relative SAR overestimation can be lowered.<br /> (© 2024 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.) |
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| ISSN: | 1522-2594 |
| DOI: | 10.1002/mrm.30235 |