A novel passive shimming optimization method of MRI magnet based on a PSA-SQP hybrid algorithm

Abstract In Magnetic Resonance Imaging (MRI), achieving a highly uniform main magnetic field (B0) is essential for producing detailed images of human anatomy. Passive Shimming (PS) is a technique used to enhance B0 uniformity by strategically arranging shimming iron pieces inside the magnet bore. Tr...

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Main Authors: Jie Zhao, Minhua Zhu, Ling Xia, Yifeng Fan, Feng Liu
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Scientific Reports
Subjects:
Online Access:https://doi.org/10.1038/s41598-025-13751-4
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author Jie Zhao
Minhua Zhu
Ling Xia
Yifeng Fan
Feng Liu
author_facet Jie Zhao
Minhua Zhu
Ling Xia
Yifeng Fan
Feng Liu
author_sort Jie Zhao
collection DOAJ
description Abstract In Magnetic Resonance Imaging (MRI), achieving a highly uniform main magnetic field (B0) is essential for producing detailed images of human anatomy. Passive Shimming (PS) is a technique used to enhance B0 uniformity by strategically arranging shimming iron pieces inside the magnet bore. Traditionally, PS optimization has been implemented using Linear Programming (LP), posing challenges in balancing field quality with the quantity of iron used for shimming. This work aims to improve the efficacy of passive shimming by optimally balancing field quality, iron usage, and harmonics, leading to a smoother field profile. This study introduces a hybrid algorithm that combines a Pattern Search Algorithm with Sequential Quadratic Programming (PSA-SQP) to enhance shimming performance. Additionally, a regularization method is employed to effectively reduce the use of iron pieces. The magnetic field improved from 462 ppm to 6.7 ppm, utilizing merely 0.8 kg of iron in a 400 mm Diameter of Spherical Volume (DSV) of a 7T MRI magnet. Compared to traditional LP optimization techniques, this method notably enhanced magnetic field uniformity by 98.5% and reduced the iron weight requirement by 91.7%, showcasing impressive performance. The proposed new passive shimming algorithm is more effective in improving magnetic field uniformity for MRI applications.
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spelling doaj-art-aaa1da7898e04151ba3239858edb7b482025-08-20T04:02:46ZengNature PortfolioScientific Reports2045-23222025-08-0115111010.1038/s41598-025-13751-4A novel passive shimming optimization method of MRI magnet based on a PSA-SQP hybrid algorithmJie Zhao0Minhua Zhu1Ling Xia2Yifeng Fan3Feng Liu4School of Medical Imaging, Hangzhou Medical CollegeSchool of Medical Imaging, Hangzhou Medical CollegeKey Laboratory of Biomedical Engineering, Ministry of Education, Zhejiang UniversitySchool of Medical Imaging, Hangzhou Medical CollegeSchool of Information Technology and Electrical Engineering, The University of QueenslandAbstract In Magnetic Resonance Imaging (MRI), achieving a highly uniform main magnetic field (B0) is essential for producing detailed images of human anatomy. Passive Shimming (PS) is a technique used to enhance B0 uniformity by strategically arranging shimming iron pieces inside the magnet bore. Traditionally, PS optimization has been implemented using Linear Programming (LP), posing challenges in balancing field quality with the quantity of iron used for shimming. This work aims to improve the efficacy of passive shimming by optimally balancing field quality, iron usage, and harmonics, leading to a smoother field profile. This study introduces a hybrid algorithm that combines a Pattern Search Algorithm with Sequential Quadratic Programming (PSA-SQP) to enhance shimming performance. Additionally, a regularization method is employed to effectively reduce the use of iron pieces. The magnetic field improved from 462 ppm to 6.7 ppm, utilizing merely 0.8 kg of iron in a 400 mm Diameter of Spherical Volume (DSV) of a 7T MRI magnet. Compared to traditional LP optimization techniques, this method notably enhanced magnetic field uniformity by 98.5% and reduced the iron weight requirement by 91.7%, showcasing impressive performance. The proposed new passive shimming algorithm is more effective in improving magnetic field uniformity for MRI applications.https://doi.org/10.1038/s41598-025-13751-4Magnetic resonance imagingPassive shimmingPattern search algorithmSequential quadratic programmingHybrid optimization
spellingShingle Jie Zhao
Minhua Zhu
Ling Xia
Yifeng Fan
Feng Liu
A novel passive shimming optimization method of MRI magnet based on a PSA-SQP hybrid algorithm
Scientific Reports
Magnetic resonance imaging
Passive shimming
Pattern search algorithm
Sequential quadratic programming
Hybrid optimization
title A novel passive shimming optimization method of MRI magnet based on a PSA-SQP hybrid algorithm
title_full A novel passive shimming optimization method of MRI magnet based on a PSA-SQP hybrid algorithm
title_fullStr A novel passive shimming optimization method of MRI magnet based on a PSA-SQP hybrid algorithm
title_full_unstemmed A novel passive shimming optimization method of MRI magnet based on a PSA-SQP hybrid algorithm
title_short A novel passive shimming optimization method of MRI magnet based on a PSA-SQP hybrid algorithm
title_sort novel passive shimming optimization method of mri magnet based on a psa sqp hybrid algorithm
topic Magnetic resonance imaging
Passive shimming
Pattern search algorithm
Sequential quadratic programming
Hybrid optimization
url https://doi.org/10.1038/s41598-025-13751-4
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