Name: use of a multi-compartment dynamic single enzyme phantom for studies of hyperpolarized magnetic resonance agents
Uploaded: 2016-04-15T14:00:00.000+00:00
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Description: Watch this Scientific Journal Video about Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents at JoVE.com

这项工作是由CPRIT补助（RP140021-P5）和朱莉娅·琼斯马修斯癌症研究学者CPRIT研究培训奖（RP140106，CMW）的支持。

注:（幻影设计）两个3毫升室进行机加工出来的Ultem的，并配有PEEK管（1.5875毫米外径0.762毫米ID）注射和排气。庭置于充满水（ 图1）的50ml离心管中。为了避免气泡产生信号的空隙，腔和管预填充去离子水（DH 2 O）。 1.溶液的制备<ol><li>制备1升缓冲溶液（81.3毫摩尔Tris pH 7.6中，203.3毫摩尔NaCl）。称取11.38克的Trizma预设晶体pH值7.6和11.88克NaCl和1升的dh 2 O的溶解</li><li>准备50毫米NADH的解决方案。称取17.8毫克β-烟酰胺腺嘌呤二核苷酸（NADH），减少的二钾盐，并在280微升被在第一步中制备的缓冲溶液中溶解。 </li><li>准备250 U / ml的酶溶液。称出乳酸脱氢酶（LDH）的78.75的活性单位，并在从s 315微升缓冲液溶解TEP之一。 </li><li>准备丙酮酸组合。称取21.4毫克Ox063三苯甲基自由基和1.26克溶解（约1毫升）[1- 13 C]丙酮酸。 </li><li>制备溶出介质（40毫摩尔Tris pH 7.6中，40毫摩尔的NaOH，0.27毫摩尔EDTA和50mM NaCl）中。称出5.96克的Trizma预置晶体pH值7.6，1.6克的NaOH，0.1g的乙二胺四乙酸二钠盐水合物（EDTA）和2.9克NaCl和1升的dh 2 O溶解</li><li>制备1:10钆特醇溶液（50毫摩尔）。将1微升钆特醇在9微升卫生署2 O的8 M [13 C]尿素准备。称取1.465 5 [13 C]尿素和3毫升卫生署2 O.溶解</li></ol> 2.超极化丙酮酸的制备<ol><li>在样品杯的动态核极化（DNP）系统中，移液管的钆特醇溶液0.3微升和丙酮酸溶液的13毫克（〜10微升）。 </li><li>简要地搅动与枪头样品杯该混合物。&lt;/ LI&gt; <li>将样品放入DNP系统。 <ol><li>确保门给DNP系统被关闭。通过点击DNP系统控制台上插入样品按钮开始样品插入过程。在采样向导中选择下一个正常的样品，然后按。 </li><li>保持样品杯垂直插入杆轻轻地放在在样品杯的顶部。出现提示时，打开DNP系统，插入杯在使用插杆的变温插杆（VTI）。 </li><li>拉柱塞在样品插入杆的端部以释放样品中的变温指数。从系统中删除样品插入杆和点击DNP系统控制台上的一个按钮。 </li></ol></li><li>启动两极分化。 <ol><li>点击DNP系统控制台上的启动按钮两极分化。在RINMR软件类型.HYPERSENSENMR推出极化监控软件。设置建立的配置为1，按回车键。然后点击坚实的基础ū页。 </li><li>设置保存文件的位置和名称。请在下拉DNP系统控制台选项卡上的13-C的配置文件，然​​后单击下一步。勾选积累过程中采样，样本集时间300秒，并点击完成。 </li></ol></li><li>量出3.85克（〜4ml）中的溶解介质中或者通过用5毫升注射器体积或通过使用秤的重量。 </li></ol> 3.幻影酶的制备<ol><li>填充〜3毫升[13℃]的尿素溶液中的微量离心管中，并将其放置在50ml离心管中。填写50ml离心管，卫生署2 O. </li><li>通过注入〜3毫升的dh 2 O成幻影的注射线，注意冲洗形成任何气泡预填充这两个酶商会和与卫生署2 O线。 </li><li>放置假体与容易进入注射线磁铁的中心。确保有一些容器赶上那会发泄出来到t液体<html>他排气管。 </li><li>制备高活性酶混合物（17.14毫米NADH，44.57 U / ml的LDH）。混合在一起240微升NADH溶液，125微升的LDH溶液和335微升缓冲液和保持在一个3毫升注射器可以连接到注入线。 注意:一旦从DNP系统500微升的40mM丙酮酸结合，最终幻象体积将1.2毫升16.7毫丙酮酸，10毫NADH，并与pH值Tris缓冲溶液26 U / L LDH的浓度〜 7.5。 </li><li>制备低活性的酶的混合物（17.14毫NADH 26.79单位/毫升，LDH）混合在一起240微升NADH溶液，75微升的LDH溶液和385微升缓冲液和保持在一个单独的3毫升注射器可以连接到注入线。 注意:一旦与500微升从DNP系统40毫丙酮酸结合最终幻象体积将1.2毫升16.7毫丙酮酸，10mM的NADH的浓度，并与pH值Tris缓冲溶液15.625 U / L LDH〜7.5 。 </li></ol>jove_title"&gt; 4。运行任何质量保证（QA）和定位扫描<ol><li>初始定位。 <ol><li>加载操作模式[1 H] TX / RX音量模式一个新的Flash定位扫描。更改设置尺寸2:光谱仪控制工具 - &gt;编辑GS - &gt;安装尺寸 - &gt; 2.按GSP的光谱仪控制，直到在磁体中心的移动幻象。按STOP然后按GOP的光谱仪控制。 </li></ol></li><li>引导扫描。 <ol><li>加载操作模式[1 H] TX / RX音量模式新TriPiolt定位扫描。位置切片:扫描控制 - &gt;切片工具 - &gt;动片（按住M键单击并拖动，选择片与片包移动滑块）。 </li><li>摆动1小时线圈:光谱仪控制工具- &gt; ACQ - &gt;摆动。调整和背后的磁铁，按STOP比赛1小时线圈。按住shift键按下扫描控制窗口上的红绿灯。 </li></ol></li></ol><p类="jove_title"&gt; 5。径向回波平面光谱成像扫描设置<ol><li>装入新的径向平面回波波谱成像（radEPSI）运作模式[13 C] TX / RX音量模式进行扫描。位置切片:切片工具上的扫描控制和移动切片（按住M键单击并拖动，选择片与片包移动滑块）。 </li><li>摆13 C线圈通过点击光谱仪控制工具- &gt; ACQ - &gt;摆动。设置接收机增益1000-2000的光谱仪。 </li><li>执行最后的系统检查。根据不同的顺序，从一名球探协议尿素室观察碳-13信号。 注意:这确保了系统开始不可逆转的溶解过程之前设置正确。 </li></ol> 6.运行解散<ol><li>当丙酮酸已经达到&gt; 90％的偏振（〜1小时），将溶液和幻象准备好了，并且扫描被构造点击DNP SY运行溶解按钮干的控制台。 </li><li>当系统提示移动溶解粘到其操作位置，注入溶出介质。关闭DNP系统，然后单击DNP系统控制台上的按钮完成。将溶解粘回提示依次完成时休息的位置。 </li><li>当DNP系统提供的超极化的丙酮酸（〜加热开始后2分钟）撤回500微升丙酮酸溶液到每个高和低浓度的酶溶液注射器。缓慢（〜10秒）注​​入每个注射器到注射线。 注:扫描可能已经启动之前注射或随时到3分钟后喷射取决于所使用的扫描协议。 </li></ol> 7.图像处理注:此幻象是专为与许多成像策略的使用。参见图2，随着RAD-EPSI图像的方式用Matlab处理的例子。 <ol><li>从FID文件加载原始数据。 ReshaPE的数据来匹配突起的数目，读出的点，回波和帐户存储为实部和虚成对数据。分离出偶数和奇数回声分。 </li><li>傅立叶变换或者偶数或奇数回波沿着回波尺寸。可视地识别为丙酮酸和乳酸的频带。为简单起见，使用的频谱的绝对值。 </li><li>分隔每个波段的代谢产物和傅立叶沿频率编码方向产生孤立的正弦图的每个变换的代谢产物。逆Radon变换独立正弦图，以产生乳酸或丙酮酸的形象。 </li></ol>

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超极化的代谢物实时成像具有序列设计，验证和质量控制许多独特的挑战。解决时空和光谱异质性的能力提供大量的临床潜力，但是排除了与常规MRI相关的质量保证和验证方法。复杂的成像序列或重建算法可能会有细微的依赖使得它们难以定性或验证成像实验之外。生物的异质性和其它实际问题限制使用的在体内和体外模型来表征或验证序列，硬件或数据处理算法。 <p class...

的13 C标记的化合物的超极化的磁共振成像（MRI）的临床影响主要取决于其测量流经实时磁共振光谱学和光谱成像1-5化学转化率的能力。期间顺序开发和验证，动态化学转化一般是通过在体内或体外模型6-9，提供有限的控制和再现性来实现的。对于稳健的测试和质量保证，它保留了化学转化特有的这种测量更多的控制系统将是首选。我们概述实现使用动态单一酶虚线可重复的方式这种转换的方法。 与超极化13 C制剂的研究大多集中于一个正常运作的生物环境成像超极化基板。这是显而易见的选择，如果目标是研究生物人处理或确定在临床护理潜在影响。然而，如果一些测量系统或数据处理算法的表征是期望的，生物模型有许多缺点，如固有的空间和时间变化10。然而，传统的静态幻影缺乏化学转化驱动在超极化基底的MRI主要临床利益，并且不能用于表征转化率或其他动态参数11的检测。使用单一酶系统，我们可以提供可控的和可重复的化学转化，从而实现动态显像策略严格的审查。 该系统是针对谁正在开发的成像策略超极化基板，并希望反对其他方法相比性能特征调查。如果静态测量所需的终结点，然后静13 C-标有代谢幻影无线会足够了11。在另一端，如果更复杂的生物特征是该方法（交货，蜂窝密度等 ）则实际的生物模型，将需要12-14的关键。该系统非常适合的，旨在提供明显的化学转化率的定量测量成像战略评估。

<table><tbody><tr><td>BioSpect 7T</td><td>Bruker</td><td>BioSpec 70/30 USR</td><td>7 Tesla Pre-Clinical MRI Scanner</td></tr><tr><td>HyperSense</td><td>Oxford Instruments</td><td>Hypersense DNP Polarizer</td><td>Dynamic Nuclear Polarizer for MRI agents</td></tr><tr><td>1-&lt;sup&gt;13&lt;/sup&gt;C-Pyrvic Acid</td><td>Sigma Aldrich</td><td>677175</td><td>Carbon 13 labled neat pyruvic acid</td></tr><tr><td>Trityl Radical</td><td>GE Healthcare</td><td>OX063</td><td>Free radical used in Dynamic Nuclear Polarization</td></tr><tr><td>NaOH</td><td>Sigma Aldrich</td><td>S8045</td><td></td></tr><tr><td>EDTA</td><td>Sigma Aldrich</td><td>E6758</td><td>Ethylenediaminetetraacetic acid</td></tr><tr><td>LDH</td><td>Worthingthon</td><td>LS002755</td><td>Lactate Dehydrogenase from rabbit muscle</td></tr><tr><td>NADH</td><td>Sigma Aldrich</td><td>N4505</td><td>&amp;beta;-Nicotinamide adenine dinucleotide, reduced dipotassium salt</td></tr><tr><td>Trizma</td><td>Sigma Aldrich</td><td>T7943</td><td>Trizma Pre-set crystals</td></tr><tr><td>NaCl</td><td>Sigma Aldrich</td><td>S7653</td><td></td></tr></tbody></table>

use of a multi-compartment dynamic single enzyme phantom for studies of hyperpolarized magnetic resonance agents

磁共振超极化底物的影像显示在实时关键的生化过程的评估重要的临床前景。由于受超极化状态施加限制的根本，充满异国情调的成像和重建技术是常用的。对于动态的，多光谱成像方法表征一个实用的系统迫切需要。这样的系统必须可重复复述正常和病理组织的相关化学动力学。最广泛使用的基材日期是超极化[1- 13 C]丙酮酸癌症代谢的评估。我们描述了介导丙酮酸至乳酸的转化基于酶的幻象系统。反应通过超极化剂的注入开始到虚线内的多个腔室，其中每一个包含不同的是控制反应速率的试剂的浓度。多个隔室是必要的，以确保伊马蔓茎序列忠实捕获组织的空间和代谢异质性。该系统将通过提供化学动力学所不具备与传统幻影，以及控制和再现那是不可能在体内帮助的先进影像战略的制定和验证。

切片选择性的2D图像用快照radEPSI序列获得。代谢物图像用滤波反投影重建。代谢图像以及与质子图像对准，如在图2中看到的，在这种系统超极化乳酸盐信号只能从超极化的丙酮酸的酶转化产生的。在图4中 ，底室，具有较高的LDH浓度，具有更强的乳酸盐和较弱丙酮酸信号相比顶室作为。使用相对代谢物信号作为酶浓度的估计的乳酸为丙酮酸比在下...

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Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents

A multi-compartment dynamic phantom is used to simulate some biology of interest for metabolic studies using hyperpolarized magnet resonance agents.

一个多腔动态单一酶幻影超极化磁共振剂研究的用途

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due ...

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Engineering

6.8K 次观看.  University of Texas M.D. Anderson Cancer Center. A multi-compartment dynamic phantom is used to simulate some biology of interest for metabolic studies using hyperpolarized magnet resonance agents.

视频: Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents

Hyperpolarized Xenon for NMR and MRI Applications

Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature 1. Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration 2.
Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization 7 and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method.
The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials 8,9. Moreover, the Xe NMR signal is extremely sensitive to its molecular environment 6. This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas 10,11. Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode.

The production of hyperpolarized xenon by means of spin exchange optical pumping (SEOP) is described. This method yields a ~10000-fold enhancement of the nuclear spin polarization of Xe-129 and has applications in nuclear magnetic resonance spectroscopy and imaging. Examples of gas phase and solution state experiments are given.

超极化氙NMR和MRI的应用

Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 ...

科研

工程学

Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging

In the past decades, new methods for tumor staging, restaging, treatment response monitoring, and recurrence detection of a variety of cancers have emerged in conjunction with the state-of-the-art positron emission tomography with 18F-fluorodeoxyglucose ([18F]-FDG PET). 13C magnetic resonance spectroscopic imaging (13CMRSI) is a minimally invasive imaging method that enables the monitoring of metabolism in vivo and in real time. As with any other method based on 13C nuclear magnetic resonance (NMR), it faces the challenge of low thermal polarization and a subsequent low signal-to-noise ratio due to the relatively low gyromagnetic ratio of 13C and its low natural abundance in biological samples. By overcoming these limitations, dynamic nuclear polarization (DNP) with subsequent sample dissolution has recently enabled commonly used NMR and magnetic resonance imaging (MRI) systems to measure, study, and image key metabolic pathways in various biological systems. A particularly interesting and promising molecule used in 13CMRSI is [1-13C]pyruvate, which, in the last ten years, has been widely used for in vitro, preclinical, and, more recently, clinical studies to investigate the cellular energy metabolism in cancer and other diseases. In this article, we outline the technique of dissolution DNP using a 3.35 T preclinical DNP hyperpolarizer and demonstrate its usage in in vitro studies. A similar protocol for hyperpolarization may be applied for the most part in in vivo studies as well. To do so, we used lactate dehydrogenase (LDH) and catalyzed the metabolic reaction of [1-13C]pyruvate to [1-13C]lactate in a prostate carcinoma cell line, PC3, in vitro using 13CMRSI.

Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging

Dynamic nuclear polarization with subsequent sample dissolution has enabled real-time studies of metabolism in biological systems. Hyperpolarized [1-13C]pyruvate was used to study lactate dehydrogenase activity in a prostate carcinoma cell line in vitro.

超极化<sup&gt; 13</sup&gt;ç代谢磁共振波谱与成像

In the past decades, new methods for tumor staging, restaging, treatment response monitoring, and recurrence detection of a variety of cancers have ...

癌症研究

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR

The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of metabolic transformations. Hyperpolarization via dissolution DNP circumvents part of the sensitivity issues thanks to the large out-of-equilibrium nuclear magnetization stemming from the electron-to-nucleus spin polarization transfer. The high NMR signal obtained can be used to monitor chemical reactions in real time. The downside of hyperpolarized NMR resides in the limited time window available for signal acquisition, which is usually on the order of the nuclear spin longitudinal relaxation time constant, T1, or, in favorable cases, on the order of the relaxation time constant associated with the singlet-state of coupled nuclei, TLLS. Cellular uptake of endogenous molecules and metabolic rates can provide essential information on tumor development and drug response. Numerous previous hyperpolarized NMR studies have demonstrated the relevancy of pyruvate as a metabolic substrate for monitoring enzymatic activity in vivo. This work provides a detailed description of the experimental setup and methods required for the study of enzymatic reactions, in particular the pyruvate-to-lactate conversion rate in presence of lactate dehydrogenase (LDH), by hyperpolarized NMR.

The sensitivity enhancement provided by dissolution dynamic nuclear polarization (DNP) enables following metabolic processes in real time by NMR and MRI. The characteristics and performances of a dedicated dissolution DNP setup designed for study enzymatic reactions are discussed.

溶出动态核极化仪器用NMR实时酶反应速率测量

The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of ...

化学

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan electron-paramagnetic-resonance (RS-EPR), which can provide quantitative information under in vivo conditions on oxygen concentration, pH, redox status and concentration of signaling molecules (i.e., OH&#8226;, NO&#8226;). The RS-EPR technique has a higher sensitivity, improved spatial resolution (1 mm), and shorter acquisition time in comparison to the standard continuous wave (CW) technique. A variety of phantom configurations have been tested, with spatial resolution varying from 1 to 6 mm, and spectral width of the reporter molecules ranging from 16 &#181;T (160 mG) to 5 mT (50 G). A cross-loop bimodal resonator decouples excitation and detection, reducing the noise, while the rapid scan effect allows more power to be input to the spin system before saturation, increasing the EPR signal. This leads to a substantially higher signal-to-noise ratio than in conventional CW EPR experiments.

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

A new electron paramagnetic resonance (EPR) method, rapid scan EPR (RS-EPR), is demonstrated for 2D spectral spatial imaging which is superior to the traditional continuous wave (CW) technique and opens new venues for in vivo imaging. Results are demonstrated at 250 MHz, but the technique is applicable at any frequency.

快速扫描电子顺磁共振打开新的途径成像生理重要参数<em&gt;在体内</em

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan ...

生物工程

High-Resolution Studies of Proteins in Natural Membranes by Solid-State NMR

Membrane proteins are vital for cell function and thus represent important drug targets. Solid-state Nuclear Magnetic Resonance (ssNMR) spectroscopy offers a unique access to probe the structure and dynamics of such proteins in biological membranes of increasing complexity. Here, we present modern solid-state NMR spectroscopy as a tool to study structure and dynamics of proteins in natural lipid membranes and at atomic scale. Such spectroscopic studies profit from the use of high-sensitivity ssNMR methods, i.e., proton-(1H)-detected ssNMR and DNP (Dynamic Nuclear Polarization) supported ssNMR. Using bacterial outer membrane beta-barrel protein BamA and the ion channel KcsA, we present methods to prepare isotope-labeled membrane proteins and to derive structural and motional information by ssNMR.

This work details robust basic routines on how to prepare isotope-labeled membrane protein samples and analyze them at high-resolution with modern solid-state NMR spectroscopy methods.

Membrane proteins are vital for cell function and thus represent important drug targets. Solid-state Nuclear Magnetic Resonance (ssNMR) spectroscopy ...

Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate

The fundamental limit to in vivo imaging applications of hyperpolarized 13C-enriched compounds is their finite spin-lattice relaxation times. Various factors affect the relaxation rates, such as buffer composition, solution pH, temperature, and magnetic field. In this last regard, the spin-lattice relaxation time can be measured at clinical field strengths, but at lower fields, where these compounds are dispensed from the polarizer and transported to the MRI, the relaxation is even faster and difficult to measure. To have a better understanding of the amount of magnetization lost during transport, we used fast field-cycling relaxometry, with magnetic resonance detection of 13C nuclei at ~0.75 T, to measure the nuclear magnetic resonance dispersion of the spin-lattice relaxation time of hyperpolarized [1-13C]pyruvate. Dissolution dynamic nuclear polarization was used to produce hyperpolarized samples of pyruvate at a concentration of 80 mmol/L and physiological pH (~7.8). These solutions were rapidly transferred to a fast field-cycling relaxometer so that relaxation of the sample magnetization could be measured as a function of time using a calibrated small flip angle (3&#176;-5&#176;). To map the T1 dispersion of the C-1 of pyruvate, we recorded data for different relaxation fields ranging between 0.237 mT and 0.705 T. With this information, we determined an empirical equation to estimate the spin-lattice relaxation of the hyperpolarized substrate within the mentioned range of magnetic fields. These results can be used to predict the amount of magnetization lost during transport and to improve experimental designs to minimize signal loss.

Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate

We present a protocol to measure the magnetic field dependence of the spin-lattice relaxation time of 13C-enriched compounds, hyperpolarized by means of dynamic nuclear polarization, using fast field-cycled relaxometry. Specifically, we have demonstrated this with [1-13C]pyruvate, but the protocol could be extended to other hyperpolarized substrates.

测量超极化 [1-13C]硫化的旋转-莱迪兹松弛磁场依赖性

The fundamental limit to in vivo imaging applications of hyperpolarized 13C-enriched compounds is their finite spin-lattice relaxation times. Various ...

Fat-Water Phantoms for Magnetic Resonance Imaging Validation: A Flexible and Scalable Protocol

As new techniques are developed to image adipose tissue, methods to validate such protocols are becoming increasingly important. Phantoms, experimental replicas of a tissue or organ of interest, provide a low cost, flexible solution. However, without access to expensive and specialized equipment, constructing stable phantoms with high fat fractions (e.g., &#62;50% fat fraction levels such as those seen in brown adipose tissue) can be difficult due to the hydrophobic nature of lipids. This work presents a detailed, low cost protocol for creating 5x 100 mL&#160;phantoms with fat fractions of 0%, 25%, 50%, 75%, and 100% using basic lab supplies (hotplate, beakers, etc.) and easily accessible components (distilled water, agar, water-soluble surfactant, sodium benzoate, gadolinium-diethylenetriaminepentacetate (DTPA) contrast agent, peanut oil, and oil-soluble surfactant). The protocol was designed to be flexible; it can be used to create phantoms with different fat fractions and a wide range of volumes. Phantoms created with this technique were evaluated in the feasibility study that compared the fat fraction values from fat-water magnetic resonance imaging to the target values in the constructed phantoms. This study yielded a concordance correlation coefficient of 0.998 (95% confidence interval: 0.972-1.00). In summary, these studies demonstrate the utility of&#160;fat phantoms for validating adipose tissue imaging techniques across a range of clinically relevant tissues and organs.

The purpose of this work is to describe a protocol for creating a practical fat-water phantom that can be customized to produce phantoms with varying fat percentages and volumes.

磁共振成像验证中的脂肪水幽灵: 一种灵活且可伸缩的协议

As new techniques are developed to image adipose tissue, methods to validate such protocols are becoming increasingly important. Phantoms, experimental ...

医学

获得高质量的超极化氙 129 磁共振图像

Troubleshooting and Quality Assurance in Hyperpolarized Xenon Magnetic Resonance Imaging: Tools for High-Quality Image Acquisition

Hyperpolarized (HP) xenon magnetic resonance imaging (129Xe MRI) is a recently federal drug administration (FDA)-approved imaging modality that produces high-resolution images of an inhaled breath of xenon gas for investigation of lung function. However, implementing 129Xe MRI is uniquely challenging as it requires specialized hardware and equipment for hyperpolarization, procurement of xenon imaging coils and coil software, development and compilation of multinuclear MR imaging sequences, and reconstruction/analysis of acquired data. Without proper expertise, these tasks can be daunting, and failure to acquire high-quality images can be&#160;frustrating, and expensive. Here, we present some quality control (QC) protocols, troubleshooting practices, and helpful tools for129Xe MRI sites, which may aid in the acquisition of optimized, high-quality data and accurate results. The discussion will begin with an overview of the process for implementing HP 129Xe MRI, including requirements for a hyperpolarizer lab, the combination of 129Xe MRI coil hardware/software, data acquisition and sequence considerations, data structures, k-space and image properties, and measured signal and noise characteristics. Within each of these necessary steps lies opportunities for errors, challenges, and unfavorable occurrences leading to poor image quality or failed imaging, and this presentation aims to address some of the more commonly encountered issues. In particular, identification and characterization of anomalous noise patterns in acquired data are necessary to avoid image artifacts and low-quality images; examples will be given, and mitigation strategies will be discussed. We aim to make the 129Xe MRI implementation process easier for new sites while providing some guidelines and strategies for real-time troubleshooting.

作者聚焦：使用超极化氙 129 MRI 研究肺部疾病 

Here, we present a protocol for obtaining high-quality hyperpolarized xenon-129 magnetic resonance images, covering hardware, software, data acquisition, sequence selection, data management, k-space utilization, and noise analysis.

超极化氙磁共振成像的故障排除和质量保证：用于高质量图像采集的工具

Hyperpolarized (HP) xenon magnetic resonance imaging (129Xe MRI) is a recently federal drug administration (FDA)-approved imaging modality that produces ...

一个多腔动态单一酶幻影超极化磁共振剂研究的用途

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超极化氙NMR和MRI的应用

超极化

溶出动态核极化仪器用NMR实时酶反应速率测量

快速扫描电子顺磁共振打开新的途径成像生理重要参数

High-Resolution Studies of Proteins in Natural Membranes by Solid-State NMR

测量超极化 [1-¹³C]硫化的旋转-莱迪兹松弛磁场依赖性

磁共振成像验证中的脂肪水幽灵: 一种灵活且可伸缩的协议

超极化氙磁共振成像的故障排除和质量保证：用于高质量图像采集的工具

超极化氙磁共振成像的故障排除和质量保证：用于高质量图像采集的工具

超极化氙磁共振成像的故障排除和质量保证：用于高质量图像采集的工具