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Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering最新文献

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IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-10-03 DOI: 10.1002/cmr.b.21391
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引用次数: 0
Tabletop 700 MHz electron paramagnetic resonance imaging spectrometer 台式700兆赫电子顺磁共振成像光谱仪
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-09-14 DOI: 10.1002/cmr.b.21384
Laura A. Buchanan, George A. Rinard, Richard W. Quine, Sandra S. Eaton, Gareth R. Eaton
{"title":"Tabletop 700 MHz electron paramagnetic resonance imaging spectrometer","authors":"Laura A. Buchanan,&nbsp;George A. Rinard,&nbsp;Richard W. Quine,&nbsp;Sandra S. Eaton,&nbsp;Gareth R. Eaton","doi":"10.1002/cmr.b.21384","DOIUrl":"10.1002/cmr.b.21384","url":null,"abstract":"<p>Low frequency electron paramagnetic resonance imaging is a powerful tool to noninvasively measure the physiological status of tumors. Here, we report on the design and functionality of a rapid scan and pulse tabletop imaging spectrometer based around an arbitrary waveform generator and 25 mm cross-loop resonator operating at 700 MHz. Two and four-dimensional rapid scan spectral-spatial images are presented. This tabletop imager is a prototype for future preclinical imagers.</p>","PeriodicalId":50623,"journal":{"name":"Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering","volume":"48B 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cmr.b.21384","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36998985","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: 6
General purpose electronics for real-time processing and encoding of non-MR data in MR acquisitions 在磁共振采集中用于实时处理和编码非磁共振数据的通用电子器件
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-09-05 DOI: 10.1002/cmr.b.21385
Jan Ole Pedersen, Christian G. Hanson, Rong Xue, Lars G. Hanson
{"title":"General purpose electronics for real-time processing and encoding of non-MR data in MR acquisitions","authors":"Jan Ole Pedersen,&nbsp;Christian G. Hanson,&nbsp;Rong Xue,&nbsp;Lars G. Hanson","doi":"10.1002/cmr.b.21385","DOIUrl":"10.1002/cmr.b.21385","url":null,"abstract":"<p>Recording of data other than MR signals are often of interest during MRI. We present unique, versatile circuitry developed for sampling and real-time processing of such non-MR signals to facilitate recording of these by an MR scanner. The circuitry is capable of acquiring multiple signals at 200 kHz sampling rate, measure RF power correlates, perform fast and flexible signal processing, and transmitting both amplitude and frequency modulated RF signals receivable by MR scanners. As an example of use, an electronic point-source signal is generated by the circuitry, and transmitted wirelessly to the receive coil of an MR scanner during an echo planar imaging sequence.</p>","PeriodicalId":50623,"journal":{"name":"Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering","volume":"48B 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cmr.b.21385","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86729600","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: 2
NMR Concepts 核磁共振的概念
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-08-24 DOI: 10.1002/cmr.b.21382
{"title":"NMR Concepts","authors":"","doi":"10.1002/cmr.b.21382","DOIUrl":"https://doi.org/10.1002/cmr.b.21382","url":null,"abstract":"","PeriodicalId":50623,"journal":{"name":"Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering","volume":"48B 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cmr.b.21382","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92197034","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
DVD Review DVD的评论
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-08-24 DOI: 10.1002/cmr.b.21381
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引用次数: 0
Reducing signal-to-noise ratio degradation due to coil coupling in a receiver array for 35Cl MRI at 9.4 T: A comparison of matching and decoupling strategies 减少9.4 T下35Cl MRI接收器阵列线圈耦合导致的信噪比下降:匹配和去耦策略的比较
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-08-05 DOI: 10.1002/cmr.b.21383
Matthias Malzacher, Ruomin Hu, Jorge Chacon-Caldera, Lothar R. Schad
{"title":"Reducing signal-to-noise ratio degradation due to coil coupling in a receiver array for 35Cl MRI at 9.4 T: A comparison of matching and decoupling strategies","authors":"Matthias Malzacher,&nbsp;Ruomin Hu,&nbsp;Jorge Chacon-Caldera,&nbsp;Lothar R. Schad","doi":"10.1002/cmr.b.21383","DOIUrl":"10.1002/cmr.b.21383","url":null,"abstract":"<p>Next to conventional magnetic resonance imaging (MRI), which utilizes hydrogen nuclei, other nuclei, so-called X-nuclei, are of increasing interest since they can provide additional diagnostic information. However, X-nuclei MRI is challenging due to the lower Signal-to-Noise Ratio (SNR) compared to <sup>1</sup>H (<sup>35</sup>Cl provides approximately 200 000 times lower SNR than <sup>1</sup>H). In order to compete with this challenge, the use of high-field strengths and optimized hardware is crucial. In this work, a transmit-only receive-only (TORO) system for <sup>35</sup>Cl MRI at a preclinical 9.4 T scanner is presented, composed of a volumetric birdcage coil and a 3 channel Rx array. SNR degradation despite preamplifier decoupling can no longer be neglected since the resonance frequency of <sup>35</sup>Cl is low. This paper will prove the SNR degradation due to the coil coupling of the receiver coils for this setup and evaluate three different approaches to mitigate the SNR degradation. The performance of the different approaches is evaluated via single channel and combined SNR maps using phantom measurements. Finally, the SNR maps acquired with the Rx array are compared to the SNR map acquired using the Birdcage coil as a reference.</p>","PeriodicalId":50623,"journal":{"name":"Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering","volume":"48B 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cmr.b.21383","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86514653","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: 4
A low-cost multi-channel software-defined radio-based NMR spectrometer and ultra-affordable digital pulse programmer 一个低成本的多通道软件定义的基于无线电的核磁共振光谱仪和超实惠的数字脉冲编程器
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-07-01 DOI: 10.1002/CMR.B.21401
C. Michal
{"title":"A low-cost multi-channel software-defined radio-based NMR spectrometer and ultra-affordable digital pulse programmer","authors":"C. Michal","doi":"10.1002/CMR.B.21401","DOIUrl":"https://doi.org/10.1002/CMR.B.21401","url":null,"abstract":"Funding information Natural Sciences and Engineering Research Council of Canada, Grant/Award Number: RGPIN-2014-05114 Abstract In recent years, a new generation of software‐defined radio (SDR) products has emerged that are well suited for adaptation for NMR instrumentation. The software and hardware of a new NMR spectrometer console based upon an inexpensive SDR product are described. This device is provided with open‐source firmware and drivers which have allowed the customization of its behavior and optimization for use in NMR. In particular, these low‐level modifications have allowed for straightforward synchronization of multiple SDR boards with each other and with other devices. Control of other devices is facilitated by a new digital pulse programmer constructed using an inexpensive open‐source, widely available microcontroller platform. The strategy used for precise, reproducible synchronization of the different components is described in detail. Representative spectra are presented demonstrating both high‐resolution and wide‐line spectroscopy with spectral widths up to 50 MHz.","PeriodicalId":50623,"journal":{"name":"Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering","volume":"62 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79497211","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: 16
Depiction of the perfusion components’ volume fraction distribution in generalized intravoxel incoherent motion by using Gaussian mixture model 用高斯混合模型描述广义体内非相干运动中灌注组分的体积分数分布
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-07-01 DOI: 10.1002/CMR.B.21399
Shunli Wang, Wanyu Liu, Zi-Xiang Kuai, Yuemin M. Zhu
{"title":"Depiction of the perfusion components’ volume fraction distribution in generalized intravoxel incoherent motion by using Gaussian mixture model","authors":"Shunli Wang, Wanyu Liu, Zi-Xiang Kuai, Yuemin M. Zhu","doi":"10.1002/CMR.B.21399","DOIUrl":"https://doi.org/10.1002/CMR.B.21399","url":null,"abstract":"","PeriodicalId":50623,"journal":{"name":"Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering","volume":"21 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80727465","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
Effect of PIN diode nonlinearity on decoupler circuits in magnetic resonance imaging surface coils PIN二极管非线性对磁共振成像表面线圈解耦电路的影响
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-07-01 DOI: 10.1002/cmr.b.21398
Aasrith Ganti, Timothy Ortiz, Tracy Wynn, Jenshan Lin, R. Duensing
{"title":"Effect of PIN diode nonlinearity on decoupler circuits in magnetic resonance imaging surface coils","authors":"Aasrith Ganti, Timothy Ortiz, Tracy Wynn, Jenshan Lin, R. Duensing","doi":"10.1002/cmr.b.21398","DOIUrl":"https://doi.org/10.1002/cmr.b.21398","url":null,"abstract":"Correspondence Aasrith Ganti, Philips Healthcare, Gainesville, FL and University of Florida, Gainesville, FL. Email: aasrith.ganti@philips.com Abstract Decoupler circuits are the primary circuits used to maintain safety and image quality in switching magnetic resonance imaging (MRI) surface coils. Decoupler circuits predominantly employ PIN diodes as a switch and their performance is most commonly calculated on the bench at DC and low power RF conditions. The effects of high‐power RF on PIN diode decoupler circuits are not usually measured. Experiments at high RF power levels reveal a decrease in the impedance of a typical decoupler as the PIN diode operates in the nonlinear region, effectively increasing the ON‐resistance of the PIN diode. The constraints that dictate the start of nonlinearities are studied, and ways to control these nonlinearities are presented. Furthermore, this work is used as a basis to extend and improve upon previous work that established figure of merit (FOM) for PIN diode decouplers. This study is a comprehensive guide for MRI coil designers who face the task of designing decoupler circuits for surface coils and are looking for tools to accurately estimate the dynamic impedance of the circuit over the course of an MRI sequence.","PeriodicalId":50623,"journal":{"name":"Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering","volume":"70 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85695142","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: 2
A cylindrical basis set for shim coil design in magnetic resonance imaging 磁共振成像中垫片线圈设计的圆柱形基组
IF 0.9 4区 医学
Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering Pub Date : 2018-07-01 DOI: 10.1002/CMR.B.21400
Andrew Phair, Michael Brideson, L. Forbes
{"title":"A cylindrical basis set for shim coil design in magnetic resonance imaging","authors":"Andrew Phair, Michael Brideson, L. Forbes","doi":"10.1002/CMR.B.21400","DOIUrl":"https://doi.org/10.1002/CMR.B.21400","url":null,"abstract":"Shim coils used in magnetic resonance imaging and NMR to produce magnetic fields are commonly designed to generate spherical harmonics, and thus achieve accuracy over a spherical region. Herein a cylindrical basis set is presented as an alternative to spherical harmonics, so as to better suit the cylindrical coil geometry and, in cases where it more closely matches a cylinder, the imaging region of interest. Example coil winding patterns for a selection of functions in this new set are derived using the target field method. A computational approach is taken to determine their accuracy, and it is found the basis functions are generated with high accuracy over cylindrical imaging regions within the coil. The basis set is also applied to a double-coil configuration with active shielding, which results in slightly reduced accuracy within the coil but highly effective field nullification beyond the coil radius.","PeriodicalId":50623,"journal":{"name":"Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering","volume":"152 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77997772","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: 4
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