首页 > 最新文献

Magnetic Resonance Materials in Physics, Biology and Medicine最新文献

英文 中文
Liver T1 and T2 mapping in a large cohort of healthy subjects: normal ranges and correlation with age and sex. 一大群健康受试者的肝脏T1和T2定位:正常范围及与年龄和性别的相关性
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2024-02-01 Epub Date: 2023-11-29 DOI: 10.1007/s10334-023-01135-6
Antonella Meloni, Aldo Carnevale, Paolo Gaio, Vincenzo Positano, Cristina Passantino, Alessia Pepe, Andrea Barison, Giancarlo Todiere, Chrysanthos Grigoratos, Giovanni Novani, Laura Pistoia, Melchiore Giganti, Filippo Cademartiri, Alberto Cossu

Objective: We established normal ranges for native T1 and T2 values in the human liver using a 1.5 T whole-body imager (General Electric) and we evaluated their variation across hepatic segments and their association with age and sex.

Materials and methods: One-hundred healthy volunteers aged 20-70 years (50% females) underwent MRI. Modified Look-Locker inversion recovery and multi-echo fast-spin-echo sequences were used to measure hepatic native global and segmental T1 and T2 values, respectively.

Results: T1 and T2 values exhibited good intra- and inter-observer reproducibility (coefficient of variation < 5%). T1 value over segment 4 was significantly lower than the T1 values over segments 2 and 3 (p < 0.0001). No significant regional T2 variability was detected. Segmental and global T1 values were not associated with age or sex. Global T2 values were independent from age but were significantly lower in males than in females. The lower and upper limits of normal for global T1 values were, respectively, 442 ms and 705 ms. The normal range for global T2 values was 35 ms-54 ms in males and 39 ms-54 ms in females.

Discussion: Liver T1 and T2 mapping is feasible and reproducible and the provided normal ranges may help to establish diagnosis and progression of various liver diseases.

目的:我们使用1.5 T全身显像仪(通用电气)建立了人肝脏天然T1和T2值的正常范围,并评估了它们在肝段之间的变化及其与年龄和性别的关系。材料与方法:100名年龄在20-70岁的健康志愿者(50%为女性)行MRI检查。改进的Look-Locker反演恢复和多回波快速自旋回波序列分别用于测量肝脏原生全局和局部T1和T2值。讨论:肝脏T1、T2测图是可行的、可重复的,所提供的正常范围有助于确定各种肝脏疾病的诊断和进展。
{"title":"Liver T1 and T2 mapping in a large cohort of healthy subjects: normal ranges and correlation with age and sex.","authors":"Antonella Meloni, Aldo Carnevale, Paolo Gaio, Vincenzo Positano, Cristina Passantino, Alessia Pepe, Andrea Barison, Giancarlo Todiere, Chrysanthos Grigoratos, Giovanni Novani, Laura Pistoia, Melchiore Giganti, Filippo Cademartiri, Alberto Cossu","doi":"10.1007/s10334-023-01135-6","DOIUrl":"10.1007/s10334-023-01135-6","url":null,"abstract":"<p><strong>Objective: </strong>We established normal ranges for native T1 and T2 values in the human liver using a 1.5 T whole-body imager (General Electric) and we evaluated their variation across hepatic segments and their association with age and sex.</p><p><strong>Materials and methods: </strong>One-hundred healthy volunteers aged 20-70 years (50% females) underwent MRI. Modified Look-Locker inversion recovery and multi-echo fast-spin-echo sequences were used to measure hepatic native global and segmental T1 and T2 values, respectively.</p><p><strong>Results: </strong>T1 and T2 values exhibited good intra- and inter-observer reproducibility (coefficient of variation < 5%). T1 value over segment 4 was significantly lower than the T1 values over segments 2 and 3 (p < 0.0001). No significant regional T2 variability was detected. Segmental and global T1 values were not associated with age or sex. Global T2 values were independent from age but were significantly lower in males than in females. The lower and upper limits of normal for global T1 values were, respectively, 442 ms and 705 ms. The normal range for global T2 values was 35 ms-54 ms in males and 39 ms-54 ms in females.</p><p><strong>Discussion: </strong>Liver T1 and T2 mapping is feasible and reproducible and the provided normal ranges may help to establish diagnosis and progression of various liver diseases.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"93-100"},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138451855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The role of gadolinium-based contrast agents in magnetic resonance imaging structured reporting and data systems (RADS). 钆基造影剂在磁共振成像结构化报告和数据系统(RADS)中的作用。
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2024-02-01 Epub Date: 2023-09-13 DOI: 10.1007/s10334-023-01113-y
Marco Parillo, Carlo Augusto Mallio, Aart J Van der Molen, Àlex Rovira, Ilona A Dekkers, Uwe Karst, Gerard Stroomberg, Olivier Clement, Eliana Gianolio, Aart J Nederveen, Alexander Radbruch, Carlo Cosimo Quattrocchi

Among the 28 reporting and data systems (RADS) available in the literature, we identified 15 RADS that can be used in Magnetic Resonance Imaging (MRI). Performing examinations without using gadolinium-based contrast agents (GBCA) has benefits, but GBCA administration is often required to achieve an early and accurate diagnosis. The aim of the present review is to summarize the current role of GBCA in MRI RADS. This overview suggests that GBCA are today required in most of the current RADS and are expected to be used in most MRIs performed in patients with cancer. Dynamic contrast enhancement is required for correct scores calculation in PI-RADS and VI-RADS, although scientific evidence may lead in the future to avoid the GBCA administration in these two RADS. In Bone-RADS, contrast enhancement can be required to classify an aggressive lesion. In RADS scoring on whole body-MRI datasets (MET-RADS-P, MY-RADS and ONCO-RADS), in NS-RADS and in Node-RADS, GBCA administration is optional thanks to the intrinsic high contrast resolution of MRI. Future studies are needed to evaluate the impact of the high T1 relaxivity GBCA on the assignment of RADS scores.

在文献中提供的 28 种报告和数据系统(RADS)中,我们确定了 15 种可用于磁共振成像(MRI)的 RADS。在不使用钆基造影剂(GBCA)的情况下进行检查有很多好处,但为了获得早期准确诊断,通常需要使用 GBCA。本综述旨在总结 GBCA 目前在 MRI RADS 中的作用。综述表明,目前大多数 RADS 都需要 GBCA,而且预计大多数癌症患者进行的 MRI 都会使用 GBCA。在 PI-RADS 和 VI-RADS 中,动态对比增强是正确计算分数的必要条件,但科学证据可能会导致将来在这两种 RADS 中避免使用 GBCA。在 Bone-RADS 中,需要造影剂增强才能对侵袭性病变进行分类。在根据全身 MRI 数据集(MET-RADS-P、MY-RADS 和 ONCO-RADS)、NS-RADS 和 Node-RADS 进行评分的 RADS 中,由于 MRI 本身具有高对比度分辨率,因此可以选择使用 GBCA。未来还需要进行研究,以评估高 T1 松弛性 GBCA 对 RADS 评分的影响。
{"title":"The role of gadolinium-based contrast agents in magnetic resonance imaging structured reporting and data systems (RADS).","authors":"Marco Parillo, Carlo Augusto Mallio, Aart J Van der Molen, Àlex Rovira, Ilona A Dekkers, Uwe Karst, Gerard Stroomberg, Olivier Clement, Eliana Gianolio, Aart J Nederveen, Alexander Radbruch, Carlo Cosimo Quattrocchi","doi":"10.1007/s10334-023-01113-y","DOIUrl":"10.1007/s10334-023-01113-y","url":null,"abstract":"<p><p>Among the 28 reporting and data systems (RADS) available in the literature, we identified 15 RADS that can be used in Magnetic Resonance Imaging (MRI). Performing examinations without using gadolinium-based contrast agents (GBCA) has benefits, but GBCA administration is often required to achieve an early and accurate diagnosis. The aim of the present review is to summarize the current role of GBCA in MRI RADS. This overview suggests that GBCA are today required in most of the current RADS and are expected to be used in most MRIs performed in patients with cancer. Dynamic contrast enhancement is required for correct scores calculation in PI-RADS and VI-RADS, although scientific evidence may lead in the future to avoid the GBCA administration in these two RADS. In Bone-RADS, contrast enhancement can be required to classify an aggressive lesion. In RADS scoring on whole body-MRI datasets (MET-RADS-P, MY-RADS and ONCO-RADS), in NS-RADS and in Node-RADS, GBCA administration is optional thanks to the intrinsic high contrast resolution of MRI. Future studies are needed to evaluate the impact of the high T1 relaxivity GBCA on the assignment of RADS scores.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"15-25"},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10876744/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10279210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Cranial bone imaging using ultrashort echo-time bone-selective MRI as an alternative to gradient-echo based "black-bone" techniques. 颅骨成像使用超短回波时间骨选择性MRI作为基于梯度回波的“黑骨”技术的替代方案。
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2024-02-01 Epub Date: 2023-11-07 DOI: 10.1007/s10334-023-01125-8
Nada Kamona, Brandon C Jones, Hyunyeol Lee, Hee Kwon Song, Chamith S Rajapakse, Connor S Wagner, Scott P Bartlett, Felix W Wehrli

Objectives: CT is the clinical standard for surgical planning of craniofacial abnormalities in pediatric patients. This study evaluated three MRI cranial bone imaging techniques for their strengths and limitations as a radiation-free alternative to CT.

Methods: Ten healthy adults were scanned at 3 T with three MRI sequences: dual-radiofrequency and dual-echo ultrashort echo time sequence (DURANDE), zero echo time (ZTE), and gradient-echo (GRE). DURANDE bright-bone images were generated by exploiting bone signal intensity dependence on RF pulse duration and echo time, while ZTE bright-bone images were obtained via logarithmic inversion. Three skull segmentations were derived, and the overlap of the binary masks was quantified using dice similarity coefficient. Craniometric distances were measured, and their agreement was quantified.

Results: There was good overlap of the three masks and excellent agreement among craniometric distances. DURANDE and ZTE showed superior air-bone contrast (i.e., sinuses) and soft-tissue suppression compared to GRE.

Discussions: ZTE has low levels of acoustic noise, however, ZTE images had lower contrast near facial bones (e.g., zygomatic) and require effective bias-field correction to separate bone from air and soft-tissue. DURANDE utilizes a dual-echo subtraction post-processing approach to yield bone-specific images, but the sequence is not currently manufacturer-supported and requires scanner-specific gradient-delay corrections.

目的:CT是小儿颅面畸形手术计划的临床标准。本研究评估了三种MRI颅骨成像技术作为CT无辐射替代技术的优势和局限性。方法:10名健康成年人在3T下接受三种MRI序列扫描:双射频和双回波超短回波时间序列(DURANDE)、零回波时间(ZTE)和梯度回波(GRE)。DURANDE亮骨图像是通过利用骨信号强度对RF脉冲持续时间和回波时间的依赖性生成的,而ZTE亮骨图像则是通过对数反演获得的。导出了三个颅骨分割,并使用骰子相似系数对二元掩模的重叠进行了量化。测量了颅骨测量距离,并对其一致性进行了量化。结果:三种掩模具有良好的重叠性,颅骨测量距离之间具有良好的一致性。与GRE相比,DURANDE和ZTE显示出优越的气骨对比度(即鼻窦)和软组织抑制。讨论:中兴通讯的声学噪声水平较低,但中兴通讯的图像在面部骨骼(如颧骨)附近的对比度较低,需要有效的偏场校正才能将骨骼与空气和软组织分离。DURANDE利用双回波减影后处理方法来生成骨特异性图像,但该序列目前不受制造商支持,需要扫描仪特异性梯度延迟校正。
{"title":"Cranial bone imaging using ultrashort echo-time bone-selective MRI as an alternative to gradient-echo based \"black-bone\" techniques.","authors":"Nada Kamona, Brandon C Jones, Hyunyeol Lee, Hee Kwon Song, Chamith S Rajapakse, Connor S Wagner, Scott P Bartlett, Felix W Wehrli","doi":"10.1007/s10334-023-01125-8","DOIUrl":"10.1007/s10334-023-01125-8","url":null,"abstract":"<p><strong>Objectives: </strong>CT is the clinical standard for surgical planning of craniofacial abnormalities in pediatric patients. This study evaluated three MRI cranial bone imaging techniques for their strengths and limitations as a radiation-free alternative to CT.</p><p><strong>Methods: </strong>Ten healthy adults were scanned at 3 T with three MRI sequences: dual-radiofrequency and dual-echo ultrashort echo time sequence (DURANDE), zero echo time (ZTE), and gradient-echo (GRE). DURANDE bright-bone images were generated by exploiting bone signal intensity dependence on RF pulse duration and echo time, while ZTE bright-bone images were obtained via logarithmic inversion. Three skull segmentations were derived, and the overlap of the binary masks was quantified using dice similarity coefficient. Craniometric distances were measured, and their agreement was quantified.</p><p><strong>Results: </strong>There was good overlap of the three masks and excellent agreement among craniometric distances. DURANDE and ZTE showed superior air-bone contrast (i.e., sinuses) and soft-tissue suppression compared to GRE.</p><p><strong>Discussions: </strong>ZTE has low levels of acoustic noise, however, ZTE images had lower contrast near facial bones (e.g., zygomatic) and require effective bias-field correction to separate bone from air and soft-tissue. DURANDE utilizes a dual-echo subtraction post-processing approach to yield bone-specific images, but the sequence is not currently manufacturer-supported and requires scanner-specific gradient-delay corrections.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"83-92"},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10923077/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71483190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Synthesis and evaluation of new magneto-fluorescent carbon dot based on manganese citrate for MRI imaging. 基于柠檬酸锰的新型磁荧光碳点的合成与评价。
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2024-02-01 Epub Date: 2023-10-20 DOI: 10.1007/s10334-023-01117-8
Vahid Ali, Hassan Kefayati, Mehdi Shafiee Ardestani, Afshin Pourahmad

Objective: Medical imaging techniques have widely revolutionized the diagnosis and treatment of various health conditions. Among these techniques, magnetic resonance imaging (MRI) has stood out as a noninvasive and versatile tool. Now, a breakthrough innovation called "manganese-carbon dots" is poised to enhance MRI imaging and provide physicians with even greater insight into the human body.

Materials and methods: In this study, one-pot hydrothermal method was used to fabricate magneto-fluorescent carbon quantum dots using manganese citrate, urea, and Mn2+. Manganese citrateAQ3 acted as a carbon source and contrast agent. TEM,XPS, FTIR, UV-Vis, fluorescent analysis confirmed the successful synthesis of magneto-fluorescent carbon quantum dots. The MTT assay was used to study its biocompatiblity, Finallay application of itscompound for mri imaging was investigated.

Results: Characterization Techniques confirmed the succesful synthesis of product. MTT assay showed no toxicity of this product on HEK-293 cells. In addition, it exhibited high r1 relaxivity (7.4 mM-1 S-1) suggesting excellent potential of magneto-fluorescent carbon quantum dots as MRI T1 contrast agent and enabling specific imaging.

Conclusion: Based on the results obtained, the synthesized carbon quantum dots could be used as fluorescence/MRI bimodal platform for in vivo imaging.

目的:医学影像技术已经广泛地改变了各种健康状况的诊断和治疗。在这些技术中,磁共振成像(MRI)作为一种非侵入性和多功能的工具脱颖而出。现在,一种名为“锰碳点”的突破性创新有望增强MRI成像,并为医生提供对人体更深入的了解。材料和方法:本研究采用一锅水热法,用柠檬酸锰、尿素和Mn2+制备了磁荧光碳量子点。柠檬酸锰AQ3作为碳源和造影剂。TEM、XPS、FTIR、UV-Vis、荧光分析证实了磁荧光碳量子点的成功合成。采用MTT法研究其生物相容性,最后探讨其化合物在mri成像中的应用。结果:表征技术证实了产物的成功合成。MTT法检测该产物对HEK-293细胞无毒性。此外,它表现出高的r1弛豫性(7.4mM-1 S-1),这表明磁荧光碳量子点作为MRI T1造影剂具有良好的潜力,并且能够进行特异性成像。结论:基于所得结果,合成的碳量子点可作为体内成像的荧光/MRI双峰平台。
{"title":"Synthesis and evaluation of new magneto-fluorescent carbon dot based on manganese citrate for MRI imaging.","authors":"Vahid Ali, Hassan Kefayati, Mehdi Shafiee Ardestani, Afshin Pourahmad","doi":"10.1007/s10334-023-01117-8","DOIUrl":"10.1007/s10334-023-01117-8","url":null,"abstract":"<p><strong>Objective: </strong>Medical imaging techniques have widely revolutionized the diagnosis and treatment of various health conditions. Among these techniques, magnetic resonance imaging (MRI) has stood out as a noninvasive and versatile tool. Now, a breakthrough innovation called \"manganese-carbon dots\" is poised to enhance MRI imaging and provide physicians with even greater insight into the human body.</p><p><strong>Materials and methods: </strong>In this study, one-pot hydrothermal method was used to fabricate magneto-fluorescent carbon quantum dots using manganese citrate, urea, and Mn2+. Manganese citrateAQ3 acted as a carbon source and contrast agent. TEM,XPS, FTIR, UV-Vis, fluorescent analysis confirmed the successful synthesis of magneto-fluorescent carbon quantum dots. The MTT assay was used to study its biocompatiblity, Finallay application of itscompound for mri imaging was investigated.</p><p><strong>Results: </strong>Characterization Techniques confirmed the succesful synthesis of product. MTT assay showed no toxicity of this product on HEK-293 cells. In addition, it exhibited high r1 relaxivity (7.4 mM-1 S-1) suggesting excellent potential of magneto-fluorescent carbon quantum dots as MRI T1 contrast agent and enabling specific imaging.</p><p><strong>Conclusion: </strong>Based on the results obtained, the synthesized carbon quantum dots could be used as fluorescence/MRI bimodal platform for in vivo imaging.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"139-148"},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49679182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Nonuniform sliding-window reconstruction for accelerated dual contrast agent quantification with MR fingerprinting 利用磁共振指纹技术加速双重造影剂量化的非均匀滑动窗口重构
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2024-01-13 DOI: 10.1007/s10334-023-01140-9

Abstract

Objective

MR fingerprinting (MRF) can enable preclinical studies of cell tracking by quantifying multiple contrast agents simultaneously, but faster scan times are required for in vivo applications. Sliding window (SW)-MRF is one option for accelerating MRF, but standard implementations are not sufficient to preserve the accuracy of T2*, which is critical for tracking iron-labelled cells in vivo.

Purpose

To develop a SW approach to MRF which preserves the T2* accuracy required for accelerated concentration mapping of iron-labelled cells on single-channel preclinical systems.

Methods

A nonuniform SW was applied to the MRF sequence and dictionary. Segments of the sequence most sensitive to T2* were subject to a shorter window length, preserving the T2* sensitivity. Phantoms containing iron-labelled CD8+ T cells and gadolinium were used to compare 24× undersampled uniform and nonuniform SW-MRF parameter maps. Dual concentration maps were generated for both uniform and nonuniform MRF and compared.

Results

Lin’s concordance correlation coefficient, compared to gold standard parameter values, was much greater for nonuniform SW-MRF than for uniform SW-MRF. A Wilcoxon signed-rank test showed no significant difference between nonuniform SW-MRF and gold standards. Nonuniform SW-MRF outperformed the uniform SW-MRF concentration maps for all parameters, providing a balance between T2* sensitivity of short window lengths, and SNR of longer window lengths.

Conclusions

Nonuniform SW-MRF improves the accuracy of matching compared to uniform SW-MRF, allowing higher accelerated concentration mapping for preclinical systems.

摘要 客观磁共振指纹图谱(MRF)可通过同时量化多种造影剂实现细胞追踪的临床前研究,但体内应用需要更快的扫描时间。滑动窗口(SW)-MRF 是加速 MRF 的一种选择,但标准的实现方法不足以保持 T2* 的准确性,而 T2* 对体内铁标记细胞的追踪至关重要。 目的 开发一种 MRF SW 方法,它能保持单通道临床前系统上加速铁标记细胞浓度绘图所需的 T2* 精确度。 方法 将非均匀 SW 应用于 MRF 序列和字典。序列中对 T2* 最敏感的片段需要使用较短的窗口长度,以保持 T2* 的敏感性。使用含有铁标记 CD8+ T 细胞和钆的模型来比较 24× 欠采样均匀和非均匀 SW-MRF 参数图。为均匀和非均匀 MRF 生成双浓度图并进行比较。 结果 与金标准参数值相比,非均匀 SW-MRF 的林氏一致性相关系数远大于均匀 SW-MRF。Wilcoxon 符号秩检验显示,非均匀 SW-MRF 与黄金标准之间没有显著差异。非均匀 SW-MRF 在所有参数上都优于均匀 SW-MRF 浓度图,在短窗口长度的 T2* 敏感性和长窗口长度的 SNR 之间取得了平衡。 结论 与均匀 SW-MRF 相比,非均匀 SW-MRF 提高了匹配的准确性,可为临床前系统提供更快的浓度绘图。
{"title":"Nonuniform sliding-window reconstruction for accelerated dual contrast agent quantification with MR fingerprinting","authors":"","doi":"10.1007/s10334-023-01140-9","DOIUrl":"https://doi.org/10.1007/s10334-023-01140-9","url":null,"abstract":"<h3>Abstract</h3> <span> <h3>Objective</h3> <p>MR fingerprinting (MRF) can enable preclinical studies of cell tracking by quantifying multiple contrast agents simultaneously, but faster scan times are required for in vivo applications. Sliding window (SW)-MRF is one option for accelerating MRF, but standard implementations are not sufficient to preserve the accuracy of <em>T</em><sub>2</sub>*, which is critical for tracking iron-labelled cells in vivo.</p> </span> <span> <h3>Purpose</h3> <p>To develop a SW approach to MRF which preserves the <em>T</em><sub>2</sub>* accuracy required for accelerated concentration mapping of iron-labelled cells on single-channel preclinical systems.</p> </span> <span> <h3>Methods</h3> <p>A nonuniform SW was applied to the MRF sequence and dictionary. Segments of the sequence most sensitive to <em>T</em><sub>2</sub>* were subject to a shorter window length, preserving the <em>T</em><sub>2</sub>* sensitivity. Phantoms containing iron-labelled CD8+ T cells and gadolinium were used to compare 24× undersampled uniform and nonuniform SW-MRF parameter maps. Dual concentration maps were generated for both uniform and nonuniform MRF and compared.</p> </span> <span> <h3>Results</h3> <p>Lin’s concordance correlation coefficient, compared to gold standard parameter values, was much greater for nonuniform SW-MRF than for uniform SW-MRF. A Wilcoxon signed-rank test showed no significant difference between nonuniform SW-MRF and gold standards. Nonuniform SW-MRF outperformed the uniform SW-MRF concentration maps for all parameters, providing a balance between <em>T</em><sub>2</sub>* sensitivity of short window lengths, and SNR of longer window lengths.</p> </span> <span> <h3>Conclusions</h3> <p>Nonuniform SW-MRF improves the accuracy of matching compared to uniform SW-MRF, allowing higher accelerated concentration mapping for preclinical systems.</p> </span>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":"24 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139461137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Correction to: Book of Abstracts ESMRMB 2023 Online 39th Annual Scientific Meeting 4–7 October 2023 更正为:摘要集 ESMRMB 2023 在线第 39 届科学年会 2023 年 10 月 4-7 日
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2023-12-12 DOI: 10.1007/s10334-023-01130-x
{"title":"Correction to: Book of Abstracts ESMRMB 2023 Online 39th Annual Scientific Meeting 4–7 October 2023","authors":"","doi":"10.1007/s10334-023-01130-x","DOIUrl":"https://doi.org/10.1007/s10334-023-01130-x","url":null,"abstract":"","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":"23 13","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139010016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A short-TR single-echo spin-echo breath-hold method for assessing liver T2 评估肝脏 T2 的短实时单回波自旋回波屏气法
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2023-12-10 DOI: 10.1007/s10334-023-01132-9
Marshall S. Sussman, Kartik S. Jhaveri

Objective

Conventional single-echo spin-echo T2 mapping used for liver iron quantification is too long for breath-holding. This study investigated a short TR (~100 ms) single-echo spin-echo T2 mapping technique wherein each image (corresponding to a single TE) could be acquired in ~17 s–short enough for a breath-hold. TE images were combined for T2 fitting. To avoid T1 bias, each TE acquisition incremented TR to maintain a constant TR-TE.

Materials and methods

Experiments at 1.5T validated the technique’s accuracy in phantoms, 9 healthy volunteers, and 5 iron overload patients. In phantoms and healthy volunteers, the technique was compared to the conventional approach of constant TR for all TEs. Iron overload results were compared to FerriScan.

Results

In phantoms, the constant TR-TE technique provided unbiased estimates of T2, while the conventional constant TR approach underestimated it. In healthy volunteers, there was no significant discrepancy at the 95% confidence level between constant TR-TE and reference T2 values, whereas there was for constant TR scans. In iron overload patients, there was a high correlation between constant TR-TE and FerriScan T2 values (r2 = 0.95), with a discrepancy of 0.6+/− 1.4 ms.

Discussion

The short-TR single-echo breath-hold spin-echo technique provided unbiased estimates of T2 in phantoms and livers.

目的用于肝脏铁定量的传统单回波自旋回波 T2 映像太长,不适合屏气。本研究探讨了一种短TR(约100毫秒)单回波自旋回波T2映射技术,该技术可在约17秒内获得每幅图像(对应单个TE)--短到足以进行屏气。TE图像合并后进行T2拟合。为避免 T1 偏差,每次 TE 采集都会增加 TR,以保持恒定的 TR-TE。材料和方法在 1.5T 下进行的实验验证了该技术在模型、9 名健康志愿者和 5 名铁超载患者中的准确性。在模型和健康志愿者中,该技术与所有 TE 均保持恒定 TR 的传统方法进行了比较。结果在模型中,恒定 TR-TE 技术提供了无偏的 T2 估计值,而传统的恒定 TR 方法则低估了 T2。在健康志愿者中,恒定 TR-TE 与参考 T2 值在 95% 置信度水平上没有明显差异,而恒定 TR 扫描则存在差异。在铁超载患者中,恒定TR-TE和FerriScan T2值之间有很高的相关性(r2 = 0.95),差异为0.6+/- 1.4 ms。
{"title":"A short-TR single-echo spin-echo breath-hold method for assessing liver T2","authors":"Marshall S. Sussman, Kartik S. Jhaveri","doi":"10.1007/s10334-023-01132-9","DOIUrl":"https://doi.org/10.1007/s10334-023-01132-9","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Objective</h3><p>Conventional single-echo spin-echo T2 mapping used for liver iron quantification is too long for breath-holding. This study investigated a short TR (~100 ms) single-echo spin-echo T2 mapping technique wherein each image (corresponding to a single TE) could be acquired in ~17 s–short enough for a breath-hold. TE images were combined for T2 fitting. To avoid T1 bias, each TE acquisition incremented TR to maintain a constant TR-TE.</p><h3 data-test=\"abstract-sub-heading\">Materials and methods</h3><p>Experiments at 1.5T validated the technique’s accuracy in phantoms, 9 healthy volunteers, and 5 iron overload patients<i>.</i> In phantoms and healthy volunteers, the technique was compared to the conventional approach of constant TR for all TEs. Iron overload results were compared to FerriScan.</p><h3 data-test=\"abstract-sub-heading\">Results</h3><p>In phantoms, the constant TR-TE technique provided unbiased estimates of T2, while the conventional constant TR approach underestimated it. In healthy volunteers, there was no significant discrepancy at the 95% confidence level between constant TR-TE and reference T2 values, whereas there was for constant TR scans. In iron overload patients, there was a high correlation between constant TR-TE and FerriScan T2 values (<i>r</i><sup><i>2</i></sup> = 0.95), with a discrepancy of 0.6+/− 1.4 ms.</p><h3 data-test=\"abstract-sub-heading\">Discussion</h3><p>The short-TR single-echo breath-hold spin-echo technique provided unbiased estimates of T2 in phantoms and livers.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":"44 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138563081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
FastPtx: a versatile toolbox for rapid, joint design of pTx RF and gradient pulses using Pytorch’s autodifferentiation FastPtx:使用 Pytorch 自分化技术快速联合设计 pTx 射频和梯度脉冲的多功能工具箱
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2023-12-08 DOI: 10.1007/s10334-023-01134-7
Dario Bosch, Klaus Scheffler

Objective

With modern optimization methods, free optimization of parallel transmit pulses together with their gradient waveforms can be performed on-line within a short time. A toolbox which uses PyTorch’s autodifferentiation for simultaneous optimization of RF and gradient waveforms is presented and its performance is evaluated.

Methods

MR measurements were performed on a 9.4T MRI scanner using a 3D saturated single-shot turboFlash sequence for (B_1^+) mapping. RF pulse simulation and optimization were done using a Python toolbox and a dedicated server. An RF- and Gradient pulse design toolbox was developed, including a cost function to balance different metrics and respect hardware and regulatory limits. Pulse performance was evaluated in GRE and MPRAGE imaging. Pulses for non-selective and for slab-selective excitation were designed.

Results

Universal pulses for non-selective excitation reduced the flip angle error to an NRMSE of (12.3±1.7)% relative to the targeted flip angle in simulations, compared to (42.0±1.4)% in CP mode. The tailored pulses performed best, resulting in a narrow flip angle distribution with NRMSE of (8.2±1.0)%. The tailored pulses could be created in only 66 s, making it feasible to design them during an experiment. A 90° pulse was designed as preparation pulse for a satTFL sequence and achieved a NRMSE of 7.1%. We showed that both MPRAGE and GRE imaging benefited from the pTx pulses created with our toolbox.

Conclusion

The pTx pulse design toolbox can freely optimize gradient and pTx RF waveforms in a short time. This allows for tailoring high-quality pulses in just over a minute.

目的利用现代优化方法,可在短时间内在线自由优化并行发射脉冲及其梯度波形。方法在一台9.4T核磁共振扫描仪上使用三维饱和单发涡轮闪烁序列进行MR测量,以进行(B_1^+)映射。射频脉冲模拟和优化是使用 Python 工具箱和专用服务器完成的。我们开发了一个射频和梯度脉冲设计工具箱,其中包括一个成本函数,用于平衡不同的指标并遵守硬件和法规限制。在 GRE 和 MPRAGE 成像中对脉冲性能进行了评估。结果用于非选择性激励的通用脉冲在模拟中将翻转角误差降低到相对于目标翻转角的 NRMSE (12.3±1.7)% ,而在 CP 模式中为 (42.0±1.4)%。量身定制的脉冲表现最佳,产生了窄翻转角分布,NRMSE 为 (8.2±1.0)%。定制脉冲仅需 66 秒即可创建,因此在实验过程中设计这些脉冲是可行的。我们设计了一个 90° 脉冲作为 satTFL 序列的准备脉冲,其 NRMSE 为 7.1%。结论pTx 脉冲设计工具箱可在短时间内自由优化梯度和 pTx 射频波形。这样就能在一分钟内定制出高质量的脉冲。
{"title":"FastPtx: a versatile toolbox for rapid, joint design of pTx RF and gradient pulses using Pytorch’s autodifferentiation","authors":"Dario Bosch, Klaus Scheffler","doi":"10.1007/s10334-023-01134-7","DOIUrl":"https://doi.org/10.1007/s10334-023-01134-7","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Objective</h3><p>With modern optimization methods, free optimization of parallel transmit pulses together with their gradient waveforms can be performed on-line within a short time. A toolbox which uses PyTorch’s autodifferentiation for simultaneous optimization of RF and gradient waveforms is presented and its performance is evaluated.</p><h3 data-test=\"abstract-sub-heading\">Methods</h3><p>MR measurements were performed on a 9.4T MRI scanner using a 3D saturated single-shot turboFlash sequence for <span>(B_1^+)</span> mapping. RF pulse simulation and optimization were done using a Python toolbox and a dedicated server. An RF- and Gradient pulse design toolbox was developed, including a cost function to balance different metrics and respect hardware and regulatory limits. Pulse performance was evaluated in GRE and MPRAGE imaging. Pulses for non-selective and for slab-selective excitation were designed.</p><h3 data-test=\"abstract-sub-heading\">Results</h3><p>Universal pulses for non-selective excitation reduced the flip angle error to an NRMSE of (12.3±1.7)% relative to the targeted flip angle in simulations, compared to (42.0±1.4)% in CP mode. The tailored pulses performed best, resulting in a narrow flip angle distribution with NRMSE of (8.2±1.0)%. The tailored pulses could be created in only 66 s, making it feasible to design them during an experiment. A 90° pulse was designed as preparation pulse for a satTFL sequence and achieved a NRMSE of 7.1%. We showed that both MPRAGE and GRE imaging benefited from the pTx pulses created with our toolbox.</p><h3 data-test=\"abstract-sub-heading\">Conclusion</h3><p>The pTx pulse design toolbox can freely optimize gradient and pTx RF waveforms in a short time. This allows for tailoring high-quality pulses in just over a minute.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":"48 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138555494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Optimal bi-planar gradient coil configurations for diamond nitrogen-vacancy based diffusion-weighted NMR experiments. 金刚石氮空位扩散加权核磁共振实验中最优双平面梯度线圈结构。
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2023-12-01 Epub Date: 2023-08-14 DOI: 10.1007/s10334-023-01111-0
Philipp Amrein, Fleming Bruckmaier, Feng Jia, Dominik B Bucher, Maxim Zaitsev, Sebastian Littin

Introduction: Diffusion weighting in optically detected magnetic resonance experiments involving diamond nitrogen-vacancy (NV) centers can provide valuable microstructural information. Bi-planar gradient coils employed for diffusion weighting afford excellent spatial access, essential for integrating the NV-NMR components. Nevertheless, owing to the polar tilt of roughly [Formula: see text] of the diamond NV center, the primary magnetic field direction must be taken into account accordingly.

Methods: To determine the most effective bi-planar gradient coil configurations, we conducted an investigation into the impact of various factors, including the square side length, surface separation, and surface orientation. This was accomplished by generating over 500 bi-planar surface configurations using automated methods.

Results: We successfully generated and evaluated coil layouts in terms of sensitivity and field accuracy. Interestingly, inclined bi-planar orientations close to the NV-NMR setup's requirement, showed higher sensitivity for the transverse gradient channels than horizontal or vertical orientations. We fabricated a suitable solution as a three-channel bi-planar double-layered PCB system and experimentally validated the sensitivities at [Formula: see text] and [Formula: see text] for the transverse [Formula: see text] and [Formula: see text] gradients, and [Formula: see text] for the [Formula: see text] gradient.

Discussion: We found that the chosen relative bi-planar tilt of [Formula: see text] represents a reasonable compromise in terms of overall performance and allows for easier coil implementation with a straight, horizontal alignment within the overall experimental setup.

导读:金刚石氮空位(NV)中心光学检测磁共振实验中的扩散加权可以提供有价值的微观结构信息。用于扩散加权的双平面梯度线圈提供了良好的空间访问,这对于整合NV-NMR分量至关重要。然而,由于金刚石NV中心的极倾斜大致为[公式:见文],因此必须相应地考虑主磁场方向。方法:为了确定最有效的双平面梯度线圈配置,我们研究了各种因素的影响,包括正方形边长、表面分离和表面方向。这是通过使用自动化方法生成500多个双平面表面配置来完成的。结果:我们成功地生成并评估了线圈布局的灵敏度和场精度。有趣的是,接近NV-NMR设置要求的倾斜双平面取向对横向梯度通道的灵敏度高于水平或垂直取向。我们制作了一个合适的溶液作为三通道双平面双层PCB系统,并实验验证了横向[公式:见文]和横向[公式:见文]梯度的[公式:见文]和横向[公式:见文]梯度的[公式:见文]和横向[公式:见文]梯度的[公式:见文]灵敏度。讨论:我们发现所选择的相对双平面倾斜[公式:见文本]代表了整体性能方面的合理妥协,并且允许在整个实验设置中更容易实现直线,水平对齐的线圈。
{"title":"Optimal bi-planar gradient coil configurations for diamond nitrogen-vacancy based diffusion-weighted NMR experiments.","authors":"Philipp Amrein, Fleming Bruckmaier, Feng Jia, Dominik B Bucher, Maxim Zaitsev, Sebastian Littin","doi":"10.1007/s10334-023-01111-0","DOIUrl":"10.1007/s10334-023-01111-0","url":null,"abstract":"<p><strong>Introduction: </strong>Diffusion weighting in optically detected magnetic resonance experiments involving diamond nitrogen-vacancy (NV) centers can provide valuable microstructural information. Bi-planar gradient coils employed for diffusion weighting afford excellent spatial access, essential for integrating the NV-NMR components. Nevertheless, owing to the polar tilt of roughly [Formula: see text] of the diamond NV center, the primary magnetic field direction must be taken into account accordingly.</p><p><strong>Methods: </strong>To determine the most effective bi-planar gradient coil configurations, we conducted an investigation into the impact of various factors, including the square side length, surface separation, and surface orientation. This was accomplished by generating over 500 bi-planar surface configurations using automated methods.</p><p><strong>Results: </strong>We successfully generated and evaluated coil layouts in terms of sensitivity and field accuracy. Interestingly, inclined bi-planar orientations close to the NV-NMR setup's requirement, showed higher sensitivity for the transverse gradient channels than horizontal or vertical orientations. We fabricated a suitable solution as a three-channel bi-planar double-layered PCB system and experimentally validated the sensitivities at [Formula: see text] and [Formula: see text] for the transverse [Formula: see text] and [Formula: see text] gradients, and [Formula: see text] for the [Formula: see text] gradient.</p><p><strong>Discussion: </strong>We found that the chosen relative bi-planar tilt of [Formula: see text] represents a reasonable compromise in terms of overall performance and allows for easier coil implementation with a straight, horizontal alignment within the overall experimental setup.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"921-932"},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10667408/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10045335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
A new method to improve RF safety of implantable medical devices using inductive coupling at 3.0 T MRI. 一种利用3.0 T MRI感应耦合提高植入式医疗器械射频安全性的新方法。
IF 2.3 4区 医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING Pub Date : 2023-12-01 Epub Date: 2023-08-11 DOI: 10.1007/s10334-023-01109-8
Bu S Park, Joshua W Guag, Hongbae Jeong, Sunder S Rajan, Brent McCright

Objective: To enhance RF safety when implantable medical devices are located within the body coil but outside the imaging region by using a secondary resonator (SR) to reduce electric fields, the corresponding specific absorption rate (SAR), and temperature change during MRI.

Materials and methods: This study was conducted using numerical simulations with an American Society for Testing and Materials (ASTM) phantom and adult human models of Ella and Duke from Virtual Family Models, along with corresponding experimental results of temperature change obtained using the ASTM phantom. The circular SR was designed with an inner diameter of 150 mm and a width of 6 mm. Experimental measurements were carried out using a 3 T Medical Implant Test System (MITS) body coil, electromagnetic (EM) field mapping probes, and an ASTM phantom.

Results: The magnitudes of B1+ (|B1+|) and SAR1g were reduced by 15.2% and 5.85% within the volume of interest (VoI) of an ASTM phantom, when a SR that generates opposing electromagnetic fields was utilized. Likewise, the Δ|B1+| and ΔSAR1g were reduced by up to 56.7% and 57.5% within the VoI of an Ella model containing a copper rod when an opposing SR was used.

Conclusion: A novel method employing the designed SR, which generates opposing magnetic fields to partially shield a sample, has been proposed to mitigate the risk of induced-RF heating at the VoI through numerical simulations and corresponding experiments under various conditions at 3.0 T.

目的:利用二次谐振器(SR)减小磁场、相应的比吸收率(SAR)和MRI过程中的温度变化,提高植入式医疗器械位于人体线圈内而非成像区域时的射频安全性。材料与方法:本研究采用美国材料试验学会(ASTM)模型和虚拟家庭模型中Ella和Duke的成人模型进行数值模拟,并使用ASTM模型获得相应的温度变化实验结果。设计了内径为150mm,宽度为6mm的圆形SR。实验测量使用3t医疗植入物测试系统(MITS)体线圈、电磁(EM)场测绘探头和ASTM模体进行。结果:当使用产生相反电磁场的SR时,B1+ (|B1+|)和SAR1g在ASTM模体感兴趣体积(VoI)内的大小分别降低了15.2%和5.85%。同样,当使用相反的SR时,含有铜棒的Ella模型的VoI内Δ|B1+|和ΔSAR1g减少了56.7%和57.5%。结论:通过数值模拟和相关实验,提出了一种利用所设计的SR产生相反磁场来部分屏蔽样品的新方法,以减轻在3.0 T下各种条件下VoI处的感应射频加热风险。
{"title":"A new method to improve RF safety of implantable medical devices using inductive coupling at 3.0 T MRI.","authors":"Bu S Park, Joshua W Guag, Hongbae Jeong, Sunder S Rajan, Brent McCright","doi":"10.1007/s10334-023-01109-8","DOIUrl":"10.1007/s10334-023-01109-8","url":null,"abstract":"<p><strong>Objective: </strong>To enhance RF safety when implantable medical devices are located within the body coil but outside the imaging region by using a secondary resonator (SR) to reduce electric fields, the corresponding specific absorption rate (SAR), and temperature change during MRI.</p><p><strong>Materials and methods: </strong>This study was conducted using numerical simulations with an American Society for Testing and Materials (ASTM) phantom and adult human models of Ella and Duke from Virtual Family Models, along with corresponding experimental results of temperature change obtained using the ASTM phantom. The circular SR was designed with an inner diameter of 150 mm and a width of 6 mm. Experimental measurements were carried out using a 3 T Medical Implant Test System (MITS) body coil, electromagnetic (EM) field mapping probes, and an ASTM phantom.</p><p><strong>Results: </strong>The magnitudes of B<sub>1</sub><sup>+</sup> (|B<sub>1</sub><sup>+</sup>|) and SAR<sub>1g</sub> were reduced by 15.2% and 5.85% within the volume of interest (VoI) of an ASTM phantom, when a SR that generates opposing electromagnetic fields was utilized. Likewise, the Δ|B<sub>1</sub><sup>+</sup>| and ΔSAR<sub>1g</sub> were reduced by up to 56.7% and 57.5% within the VoI of an Ella model containing a copper rod when an opposing SR was used.</p><p><strong>Conclusion: </strong>A novel method employing the designed SR, which generates opposing magnetic fields to partially shield a sample, has been proposed to mitigate the risk of induced-RF heating at the VoI through numerical simulations and corresponding experiments under various conditions at 3.0 T.</p>","PeriodicalId":18067,"journal":{"name":"Magnetic Resonance Materials in Physics, Biology and Medicine","volume":" ","pages":"933-943"},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10667457/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9965773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
期刊
Magnetic Resonance Materials in Physics, Biology and Medicine
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1