为这项研究提供资金支持的国家卫生研究院 (NIH) 和国立糖尿病和消化和肾脏疾病研究所 (NIDDK)/NIH R01-DK-105371。我们感谢 Houchun 博士 (哈利) 胡提出关于脂肪水幻影创造的建议和建议。

1. 准备工作站和材料
<ol><li>遵守所有实验室安全规则。戴上眼睛保护手套。阅读每个使用的试剂的材料安全数据表, 并采取适当的预防措施。审查材料和设备清单, 化学处理程序和玻璃器皿的预防措施。 注意: 此协议要求在高温下使用热板。在与热容器进行交互时, 请小心佩戴耐热手套, 不要接触加热板表面。</li>
	<li>清除工作区并用消毒剂清洁表面。洗你的手, 戴上手套。</li>
	<li>消毒所有的仪器和所有的玻璃罐子里面, 以减少潜在的污染风险, 并增加幻影的寿命。 注: 如果幻影将使用超过两天, 定期清洁表面的完整的幻影与乙醇, 以防止细菌生长。</li>
</ol>2. 准备水溶液
<ol><li>为水溶液准备工作区。将下列材料和设备放置在工作台上: 毕业气缸, 400 毫升烧杯, 搅拌杆, 鳞片, 2x 重量船, 刮刀, 2x 1.0 毫升注射器用针, 蒸馏水, 钆-diethylenetriaminepentacetate (DTPA) 造影剂,水溶性表面活性剂, 琼脂, 苯甲酸钠。 注: 注射器可用于或不使用针头。然而, 使用针头将提高测量的准确性, 并有助于防止飞溅时, 内容是添加到水或油溶液。</li>
	<li>将搅拌杆放入400毫升烧杯中。使用100或200毫升的刻度筒来测量300毫升蒸馏水并将水倒入烧杯中。将烧杯放在热板上, 并设置在90°c, 搅拌率为 100 rpm。 注意: 在本协议中使用高温来实现快速的结果。由于溶液不留在热板上很长一段时间, 加热板的设定点温度并不反映溶液的温度。</li>
	<li>使用校准的刻度来测量0.30 克苯甲酸钠成一条重船。在水溶液中加入苯甲酸钠。</li>
	<li>用注射器测量水溶性表面活性剂的0.6 毫升。确保没有气泡。将针放在溶液中心几毫米, 慢慢释放水溶性表面活性剂, 避免溅在烧杯壁上。</li>
	<li>使用干净的注射器, 测量0.24 毫升的钆-DTPA 造影剂。使用与步骤2.4 相同的技术, 将其添加到烧杯中。 注: DTPA 用于调节幻像的 MRI 松弛特性, 以匹配感兴趣的组织。读者可以调整添加的 DTPA 的体积, 以更好地匹配的松弛性质的组织的兴趣。</li>
	<li>测量9.0 克琼脂成一条重船。用铲子慢慢把琼脂舀进烧杯里。</li>
	<li>一旦把所有的东西都添加到水溶液中, 增加热板温度到350°c 和搅拌棒速度到 1100 rpm 5-10 分钟融化琼脂。<ol>
<li>要检查琼脂是否熔化, 请简单地从热板中取出水溶液, 停止搅拌, 并检查溶液的颜色。熔化的琼脂应该是清楚的 (没有彩带或团簇) 和黄色或琥珀色。</li>
	</ol>
</li>
	<li>一旦琼脂完全熔化, 使用注射器或倒约3.5 毫升的水溶液成一个小瓶子。如果测试解决方案没有设置或分离后5-10 分钟, 琼脂没有融化。将热板温度提高回350摄氏度, 并继续加热溶液。</li>
	<li>重复步骤 2.8, 直到测试瓶中的水溶液正确设置。</li>
	<li>把水溶液放在热板上50摄氏度和 100 rpm。清洁工作空间, 准备油溶液。<ol>
<li>从工作台中取出以下材料: 鳞片, 2x 重量船, 铲, 2x 1.0 毫升注射器用针 (使用), 蒸馏水, 钆 DTPA 对比剂, 水溶性表面活性剂, 琼脂, 苯甲酸钠。</li>
		<li>将下列材料和设备放置在工作台上: 400 毫升烧杯 (清洁), 搅拌棒 (清洁), 2.0 毫升注射器与针, 花生油, 油溶性表面活性剂。</li>
	</ol>
</li>
</ol>3. 油溶液
<ol><li>将一个新的搅拌条放入一个干净的400毫升烧杯。使用一个毕业的气缸来测量300毫升的花生油和倒入烧杯。除去含有水溶液的烧杯, 将油溶液烧杯放在热板上。设置为90°c, 搅拌率为 100 rpm 1 分钟。 注: 花生油的使用, 因为它有一个类似的核磁共振谱比甘油三酯在人体脂肪组织15。<ol>
<li>不要把油放在热板上无人看管。如果油太热, 开始冒烟, 把它从热板上取出, 在将油送到加热板之前降低温度。</li>
	</ol>
</li>
	<li>用干净的注射器测量3.0 毫升的油溶性表面活性剂。使用步骤2.4 中描述的相同技术, 将油溶性表面活性剂添加到烧杯中。将热板设置为150°c 和 1100 rpm 5 分钟, 完全混合油溶液。</li>
	<li>从热板上取油液, 清洁工作区, 准备创建幻影。<ol>
<li>从工作台中取出以下材料: 2.0 毫升注射器 (用针)、花生油和油溶性表面活性剂。</li>
		<li>将下列材料和设备放置在工作台上: 250 毫升锥形瓶、搅拌棒 (清洁)、容积吸管、容积式吸管架和 5x 120 毫升玻璃罐。</li>
	</ol>
</li>
</ol>4. 创建幻像乳液
<ol><li>准备水和油溶液的容积吸管。吸管应仅与各自的解决方案一起使用, 以防止交叉污染。<ol>
<li>将吸管的大小与协议中使用的卷相匹配。例如, 使用 2x 50 毫升容积吸管 (50 毫升水溶液 + 50 毫升油溶液) 创建一个100毫升幻影与目标 FF 50% 脂肪。</li>
	</ol>
</li>
	<li>将水溶液放在热板上, 并将热板设置为300°c 和 1100 rpm。4-5 分钟后, 把搅拌器关掉。</li>
	<li>使用容积式吸管, 检查水溶液是否可以通过部分填充溶液的小量 (5-10 毫升) 的吸管, 并释放回烧杯中来提取。如果水溶液可以很容易地去除和释放, 而不过量残留在吸管, 移动到下一步, 否则, 留在热板和检查再次在2-3 分钟。 注: 水溶液的成分更容易设置和分离, 所以最好保持水溶液搅拌和/或温暖尽可能经常。如果水溶液在转移前没有被加热和搅拌, 那么在冷却时, 由于琼脂对凝结的倾向, 就很难测量出准确的体积。</li>
	<li>小心地添加一个干净的搅拌条到250毫升锥形瓶。从热板上取水溶液, 测量适当的容积 (表 2), 并将其转移到锥形烧瓶中。</li>
	<li>将油溶液放在热板上, 并设置在90°c 和 1100 rpm, 以确保解决方案是均匀的。1-2 分钟后, 从热板中取出油溶液, 用锥形瓶替换。</li>
	<li>测量适量的油溶液 (表 2), 并慢慢地添加到水溶液中的锥形瓶。</li>
	<li>一旦添加了所有的油溶液, 将温度提高到300摄氏度, 并保持 1100 rpm 的搅拌。搅拌混合溶液4-5 分钟 (应该有漩涡从搅拌杆)。乳液应该是白色的, 有奶油质地。</li>
	<li>使用磁性搅拌条猎犬移除搅拌条。 注: 搅拌棒猎犬应用于去除所有未来乳液的搅拌条。在每次使用之间彻底清洗。</li>
	<li>使用耐热手套小心倒入锥形瓶中的混合物成一个干净的120毫升玻璃罐子。慢慢地将混合物倒在玻璃罐的一侧, 以防混合物中的气泡冷却。</li>
	<li>清洁锥形瓶和搅拌棒, 然后重复步骤 4.2-4.8, 调整水和油溶液的数量, 直到所有的幽灵被创造。 注意: 清洁前要确保玻璃冷却。</li>
</ol>

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提交人声明, 这项研究是在没有任何商业或金融关系的情况下进行的, 这可能被理解为潜在的利益冲突。

我们描述了一种健壮的方法来创建脂肪水幽灵, 适合验证的医学成像技术, 用于量化脂肪组织和甘油三酯含量的体内。通过创建两个水库 (一个用于石油解决方案, 一个用于水溶液), 在不需要昂贵设备的情况下建造了各种 FF 值 (包括超过50% 的值) 的稳定幽灵。高 ff 幽灵 (> 50%) 提供的效用, 以确保脂肪定量成像技术是有效的组织或器官的高 FF 值, 如褐色脂肪组织5。对 FSF 的 MRI ...

使用成像方式 (如磁共振成像) 对脂肪组织和甘油三酯含量进行定量的兴趣扩展到许多领域。研究领域包括调查白色和褐色脂肪组织库和异位储存的脂质在器官和组织, 如肝脏1, 胰腺2, 骨骼肌肉3。随着这些新的脂肪定量技术的发展, 需要方法来证实成像参数对研究和临床应用是有效的。
幽灵, 一个组织或器官的实验复制品, 提供一个低成本, 灵活, 和控制的工具, 以开发和验证成像技术4。具体地说, 幽灵可以被构造成由脂肪和水组成的体积比或脂肪分数 (FF) 可比的组织的临床兴趣。临床上, 在组织和器官中的 ff 值可能会有很大变化: 在褐色脂肪组织中的 ff 介于29.7% 和 93.9%5之间;脂肪变性患者平均肝 FF 为 18.1, 9.0%6;成人的胰腺 FF 在2型糖尿病风险范围在1.6% 和 22.2%7之间;在一些晚期疾病的情况下, 杜氏肌营养不良症患者的 FF 价值在某些肌肉中的 90%,8。
由于非极性分子, 如脂质在溶液中不能溶解, 如水等极性分子, 创建稳定的幽灵与高目标 FF 仍然是挑战。对于 FF 高达 50%, 许多现有的方法可以用来创建脂肪水幽灵9,10,11,12。其他实现更高 FFs 的方法通常需要昂贵的设备, 如均质机或超声波细胞干扰器13,14。尽管这些技术为高 FF 幽灵提供了路线图, 设备限制和不同数量的实验细节限制了创造可重现和健壮的脂肪水幽灵的努力。
在这些以前的技术基础上, 我们开发了一种在可定制的 FF 值范围内构建经济高效、稳定的脂肪水幽灵的方法。此协议详细说明了使用单个热板使 5x 100 毫升的 fat 幻影具有0%、25%、50%、75% 和100% 的 FF 值所需的步骤。它可以很容易地调整, 以创建各种体积 (10 至200毫升) 和脂肪百分比 (0 到 100%)。在比较脂肪-水 MRI FF 值与构造幽灵的目标 FF 值的可行性研究中, 对幻像技术的有效性进行了评价。

<table><tbody><tr><td>Distilled Water</td><td>Amazon</td><td>B000P9BY38</td><td>Base of water solution</td></tr><tr><td>Agar</td><td>Sigma Aldrich Incorporated</td><td>A1296-100G</td><td>Gelling agent</td></tr><tr><td>Water-Soluble Surfactant</td><td>Sigma Aldrich Incorporated</td><td>P1379-500ML</td><td>Surfactant/emulsifying agent</td></tr><tr><td>Gadolinium-DTPA Contrast Agent</td><td>Bayer Healthcare</td><td>50419-0188-01</td><td>Magnetic Resonance Imaging Contrast Agent.</td></tr><tr><td>Sodium Benzoate</td><td>Sigma Aldrich Incorporated</td><td>71300-250G</td><td>Preservative</td></tr><tr><td>Peanut Oil</td><td>Amazon</td><td>54782-LOU</td><td>Base of oil solution</td></tr><tr><td>Oil-Soluble Surfactant</td><td>Sigma Aldrich Incorporated</td><td>S6760-250ML</td><td>Surfactant/emulsifying agent</td></tr><tr><td>Hotplate w/ Stirrer</td><td>Fisher Scientific</td><td>07-770-152</td><td></td></tr><tr><td>Stir bars (Egg-Shaped)</td><td>Sigma Aldrich Incorporated</td><td>Z127116-1EA</td><td></td></tr><tr><td>400 mL Beaker</td><td>Sigma Aldrich Incorporated</td><td>CLS1003400-48EA</td><td></td></tr><tr><td>250 mL Erlenmeyer Flask</td><td>Sigma Aldrich Incorporated</td><td>CLS4450250-6EA</td><td></td></tr><tr><td>25 mL Glass Volumetric Pipette</td><td>Fisher Scientific</td><td>13-650-2P</td><td>Quantity = 2</td></tr><tr><td>50 mL Glass Volumetric Pipette</td><td>Fisher Scientific</td><td>13-650-2S</td><td>Quantity = 2</td></tr><tr><td>75 mL Glass Volumetric Pipette</td><td>Fisher Scientific</td><td>13-650-2T</td><td>Quantity = 2</td></tr><tr><td>3.0 mL Syringe</td><td>Sigma Aldrich Incorporated</td><td>Z248002-1PAK</td><td></td></tr><tr><td>1.0 mL Syringe</td><td>Sigma Aldrich Incorporated</td><td>Z230723-1PAK</td><td></td></tr><tr><td>Spatula</td><td>Sigma Aldrich Incorporated</td><td>S3897-1EA</td><td></td></tr><tr><td>Scale (100g X 0.01g Resolution)</td><td>Amazon</td><td>AWS-100-BLK</td><td></td></tr><tr><td>Weigh Boats</td><td>Sigma Aldrich Incorporated</td><td>Z740499-500EA</td><td></td></tr><tr><td>120 mL Glass Jars</td><td>McMaster Carr Supply Co</td><td>3801T73</td><td></td></tr><tr><td>Heat Resistant Gloves (pair)</td><td>Amazon</td><td>B075GX43MN</td><td></td></tr><tr><td>Syringe Needles</td><td>Sigma Aldrich Incorporated</td><td>Z192341-100EA</td><td></td></tr><tr><td>18&quot; stir bar retriver</td><td>Fisher Scientific</td><td>14-513-70</td><td></td></tr><tr><td>1 Dram Clear Glass Vial</td><td>Fisher Scientific</td><td>03-339-25B</td><td></td></tr></tbody></table>

fat-water phantoms for magnetic resonance imaging validation: a flexible and scalable protocol

随着新技术的发展, 图像脂肪组织, 验证这种协议的方法变得越来越重要。幽灵, 实验复制品的组织或器官的利益, 提供一个低成本, 灵活的解决方案。然而, 如果没有昂贵和专门的设备, 构建一个高脂肪组分的稳定幽灵(例如, > 50% 脂肪分数水平, 如棕色脂肪组织中看到的), 可能会因为脂质的疏水性而难以使用。这项工作提出了一个详细的, 低成本的协议, 以创建 5x 100 mL 幽灵与脂肪分数的 0%, 25%, 50%, 75% 和100% 使用基本实验室用品 ( 热板, 烧杯等) 和容易接近的成分 (蒸馏水, 琼脂, 水溶性表面活性剂, 苯甲酸钠, 钆-diethylenetriaminepentacetate (DTPA) 对比剂, 花生油, 油溶性表面活性剂)。该议定书的设计是灵活的;它可以用来创建不同的脂肪分数和广泛的体积的幽灵。在可行性研究中评估了用这种技术创建的幽灵, 将脂肪-水磁共振成像的脂肪分数值与构造的幽灵中的目标值进行了比较。本研究取得了 0.998 (95% 置信区间: 0.972-1. 00) 的和谐相关系数。总之, 这些研究表明, 脂肪幽灵的效用, 以验证脂肪组织成像技术在一系列临床相关组织和器官。

如果正确地准备了水溶液, 少量的溶液应该凝结快速地在一个测试瓶中 (图 1,左)。如果解决方案分离 (图 1,右), 则应再次准备解决方案 (按照协议步骤3.8 中的指示)。如果乳液分离 (图 2中的例子,左和右), 幻影是不可行的, 应该被丢弃。当这种情况发生时, 通常是因为乳?...

Watch this Scientific Journal Video about Fat-Water Phantoms for Magnetic Resonance Imaging Validation: A Flexible and Scalable Protocol at JoVE.com

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

这项工作的目的是描述一个协议, 创建一个实用的脂肪水幻影, 可以定制, 以产生不同的脂肪百分比和体积的幽灵。

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 ...

fat-water-phantoms-for-magnetic-resonance-imaging-validation-flexible

Research

JoVE Journal

Medicine

11.2K 次观看.  Vanderbilt University Medical Center. 这项工作的目的是描述一个协议, 创建一个实用的脂肪水幻影, 可以定制, 以产生不同的脂肪百分比和体积的幽灵。

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

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

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due to fundamental constraints imposed by the hyperpolarized state, exotic imaging and reconstruction techniques are commonly used. A practical system for characterization of dynamic, multi-spectral imaging methods is critically needed. Such a system must reproducibly recapitulate the relevant chemical dynamics of normal and pathological tissues. The most widely utilized substrate to date is hyperpolarized [1-13C]-pyruvate for assessment of cancer metabolism. We describe an enzyme-based phantom system that mediates the conversion of pyruvate to lactate. The reaction is initiated by injection of the hyperpolarized agent into multiple chambers within the phantom, each of which contains varying concentrations of reagents that control the reaction rate. Multiple compartments are necessary to ensure that imaging sequences faithfully capture the spatial and metabolic heterogeneity of tissue. This system will aid the development and validation of advanced imaging strategies by providing chemical dynamics that are not available from conventional phantoms, as well as control and reproducibility that is not possible in vivo.

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 ...

科研

工程学

Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences

As the number of magnetic resonance imaging (MRI) scanners and patients with medical implants is constantly growing, radiologists increasingly encounter metallic implant-related artifacts in MRI, resulting in reduced image quality. Therefore, the MRI suitability of implants in terms of artifact volume, as well as the development of pulse sequences to reduce image artifacts, are becoming more and more important. Here, we present a comprehensive protocol which allows for a standardized evaluation of the artifact volume of implants on MRI. Furthermore, this protocol can be used to analyze the vulnerability of different pulse sequences to artifacts. The proposed protocol can be applied to T1- and T2-weighted images with or without fat-suppression and all passive implants. Furthermore, the procedure enables the separate and three-dimensional identification of signal loss and pile-up artifacts. As previous investigations differed greatly in evaluation methods, the comparability of their results was limited. Thus, standardized measurements of MRI artifact volumes are necessary to provide better comparability. This may improve the development of the MRI suitability of implants and better pulse sequences to finally improve patient care.

We describe a standardized method to evaluate magnetic resonance imaging artifacts caused by implants to estimate the suitability of the implants for magnetic resonance imaging and/or the vulnerability of different pulse sequences to metallic artifacts simultaneously.

评估植入物所引起的 MRI 伪影和脉冲序列易损性评估的协议

As the number of magnetic resonance imaging (MRI) scanners and patients with medical implants is constantly growing, radiologists increasingly encounter ...

Tracking the Mammary Architectural Features and Detecting Breast Cancer with Magnetic Resonance Diffusion Tensor Imaging

Breast cancer is the most common cause of cancer among women worldwide. Early detection of breast cancer has a critical role in improving the quality of life and survival of breast cancer patients. In this paper a new approach for the detection of breast cancer is described, based on tracking the mammary architectural elements using diffusion tensor imaging (DTI). 
The paper focuses on the scanning protocols and image processing algorithms and software that were designed to fit the diffusion properties of the mammary fibroglandular tissue and its changes during malignant transformation. The final output yields pixel by pixel vector maps that track the architecture of the entire mammary ductal glandular trees and parametric maps of the diffusion tensor coefficients and anisotropy indices. 
The efficiency of the method to detect breast cancer was tested by scanning women volunteers including 68 patients with breast cancer confirmed by histopathology findings. Regions with cancer cells exhibited a marked reduction in the diffusion coefficients and in the maximal anisotropy index as compared to the normal breast tissue, providing an intrinsic contrast for delineating the boundaries of malignant growth. Overall, the sensitivity of the DTI parameters to detect breast cancer was found to be high, particularly in dense breasts, and comparable to the current standard breast MRI method that requires injection of a contrast agent. Thus, this method offers a completely non-invasive, safe and sensitive tool for breast cancer detection.

We describe how to obtain parametric and vector maps of the diffusion tensor of the breast using magnetic resonance imaging. The protocol and final output following imaging processing are tailored for tracking breast architectural features and detecting breast malignancy.

跟踪乳腺建筑特色与检测乳腺癌的磁共振扩散张量成像

Breast cancer is the most common cause of cancer among women worldwide. Early detection of breast cancer has a critical role in improving the quality of ...

医学

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of living systems. Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using qMRI methods. The MRI acquisition protocol begins with localizer images (used to locate the position of the body and tissue of interest within the MRI system), quality control measurements of relevant magnetic field distributions, and structural imaging for general anatomical characterization. The qMRI portion of the protocol includes measurements of the longitudinal and transverse relaxation time constants (T1 and T2, respectively). Also acquired are diffusion-tensor MRI data, in which water diffusivity is measured and used to infer pathological processes such as edema. Quantitative magnetization transfer imaging is used to characterize the relative tissue content of macromolecular and free water protons. Lastly, fat-water MRI methods are used to characterize fibro-adipose tissue replacement of muscle. In addition to describing the data acquisition and analysis procedures, this paper also discusses the potential problems associated with these methods, the analysis and interpretation of the data, MRI safety, and strategies for artifact reduction and protocol optimization.

Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using non-invasive magnetic resonance imaging methods.

骨骼肌疾病的定量磁共振成像

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of ...

Human Brown Adipose Tissue Depots Automatically Segmented by Positron Emission Tomography/Computed Tomography and Registered Magnetic Resonance Images

Reliably differentiating brown adipose tissue (BAT) from other tissues using a non-invasive imaging method is an important step toward studying BAT in humans. Detecting BAT is typically confirmed by the uptake of the injected radioactive tracer 18F-Fluorodeoxyglucose (18F-FDG) into adipose tissue depots, as measured by positron emission tomography/computed tomography (PET-CT) scans after exposing the subject to cold stimulus. Fat-water separated magnetic resonance imaging (MRI) has the ability to distinguish BAT without the use of a radioactive tracer. To date, MRI of BAT in adult humans has not been co-registered with cold-activated PET-CT. Therefore, this protocol uses 18F-FDG PET-CT scans to automatically generate a BAT mask, which is then applied to co-registered MRI scans of the same subject. This approach enables measurement of quantitative MRI properties of BAT without manual segmentation. BAT masks are created from two PET-CT scans: after exposure for 2 hr to either thermoneutral (TN) (24 &#176;C) or cold-activated (CA) (17 &#176;C) conditions. The TN and CA PET-CT scans are registered, and the PET standardized uptake and CT Hounsfield values are used to create a mask containing only BAT. CA and TN MRI scans are also acquired on the same subject and registered to the PET-CT scans in order to establish quantitative MRI properties within the automatically defined BAT mask. An advantage of this approach is that the segmentation is completely automated and is based on widely accepted methods for identification of activated BAT (PET-CT). The quantitative MRI properties of BAT established using this protocol can serve as the basis for an MRI-only BAT examination that avoids the radiation associated with PET-CT.

The method presented here uses 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET-CT) and fat-water separated magnetic resonance imaging (MRI), each scanned following 2 hr exposure to thermoneutral (24 &#176;C) and cold conditions (17 &#176;C) in order to map brown adipose tissue (BAT) in adult human subjects.

人类的褐色脂肪组织的仓库的正电子发射断层扫描/计算机断层扫描自动分段及注册磁共振图像

Reliably differentiating brown adipose tissue (BAT) from other tissues using a non-invasive imaging method is an important step toward studying BAT in ...

Viscoelastic Characterization of Soft Tissue-Mimicking Gelatin Phantoms using Indentation and Magnetic Resonance Elastography

Characterization of biomechanical properties of soft biological tissues is important to understand the tissue mechanics and explore the biomechanics-related mechanisms of disease, injury, and development. The mechanical testing method is the most straightforward way for tissue characterization and is considered as verification for in vivo measurement. Among the many ex vivo mechanical testing techniques, the indentation test provides a reliable way, especially for samples that are small, hard to fix, and viscoelastic such as brain tissue. Magnetic resonance elastography (MRE) is a clinically used method to measure the biomechanical properties of soft tissues. Based on shear wave propagation in soft tissues recorded using MRE, viscoelastic properties of soft tissues can be estimated in vivo based on wave equation. Here, the viscoelastic properties of gelatin phantoms with two different concentrations were measured by MRE and indentation. The protocols of phantom fabrication, testing, and modulus estimation have been presented.

This article presents a demonstration and summary of protocols of making gelatin phantoms that mimic soft tissues, and the corresponding viscoelastic characterization using indentation and magnetic resonance elastography.

使用压痕和磁共振弹性成像对软组织模拟明胶模型进行粘弹性表征

Characterization of biomechanical properties of soft biological tissues is important to understand the tissue mechanics and explore the ...

生物工程

Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation

Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the recognized standard-of-care for blood flow quantification based on phase contrast MRI. While such measurement of blood flow has been possible in adults for decades, methods to extend this capability to fetal blood flow have only recently been developed.
Fetal blood flow quantification in major vessels is important for monitoring fetal pathologies such as congenital heart disease (CHD) and fetal growth restriction (FGR). CHD causes alterations in the cardiac structure and vasculature that change the course of blood in the fetus. In FGR, the path of blood flow is altered through the dilation of shunts such that the oxygenated blood supply to the brain is increased. Blood flow quantification enables assessment of the severity of the fetal pathology, which in turn allows for suitable&#160;in utero&#160;patient management and planning for postnatal care.
The primary challenges of applying phase contrast MRI to the human fetus include small blood vessel size, high fetal heart rate, potential MRI data corruption due to maternal respiration, unpredictable fetal movements, and lack of conventional cardiac gating methods to synchronize data acquisition. Here, we describe recent technical developments from our lab that have enabled the quantification of fetal blood flow using phase contrast MRI, including advances in accelerated imaging, motion compensation, and cardiac gating.

Here we present a protocol for measuring fetal blood flow rapidly with MRI and retrospectively performing motion correction and cardiac gating.

通过磁共振成像和运动补偿进行人胎儿血流定量

Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the ...

Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla

The overall goal of this article is to demonstrate a state-of-the-art ultrahigh field (UHF) magnetic resonance (MR) protocol of the brain at 7.0 Tesla in multiple sclerosis (MS) patients. MS is a chronic inflammatory, demyelinating, neurodegenerative disease that is characterized by white and gray matter lesions. Detection of spatially and temporally disseminated T2-hyperintense lesions by the use of MRI at 1.5 T and 3 T represents a crucial diagnostic tool in clinical practice to establish accurate diagnosis of MS based on the current version of the 2017 McDonald criteria. However, the differentiation of MS lesions from brain white matter lesions of other origins can sometimes be challenging due to their resembling morphology at lower magnetic field strengths (typically 3 T). Ultrahigh field MR (UHF-MR) benefits from increased signal-to-noise ratio and enhanced spatial resolution, both key to superior imaging for more accurate and definitive diagnoses of subtle lesions. Hence, MRI at 7.0 T has shown encouraging results to overcome the challenges of MS differential diagnosis by providing MS-specific neuroimaging markers (e.g., central vein sign, hypointense rim structures and differentiation of MS grey matter lesions). These markers and others can be identified by other MR contrasts other than T1 and T2 (T2*, phase, diffusion) and substantially improve the differentiation of MS lesions from those occurring in other neuroinflammatory conditions such as neuromyelitis optica and Susac syndrome. In this article, we describe our current technical approach to study cerebral white and grey matter lesions in MS patients at 7.0 T using different MR acquisition methods. The up-to-date protocol includes the preparation of the MR setup including the radio-frequency coils customized for UHF-MR, standardized screening, safety and interview procedures with MS patients, patient positioning in the MR scanner and acquisition of dedicated brain scans tailored for examining MS.

Here, we present a protocol to acquire magnetic resonance (MR) images of multiple sclerosis (MS) patient brains at 7.0 Tesla. The protocol includes preparation of the setup including the radio-frequency coils, standardized interview procedures with MS patients, subject positioning in the MR scanner and MR data acquisition.

7.0特斯拉多发性硬化症的磁共振成像

The overall goal of this article is to demonstrate a state-of-the-art ultrahigh field (UHF) magnetic resonance (MR) protocol of the brain at 7.0 Tesla in ...

使用 Dixon MRI 的综合 3D 肝脏脂肪功能分布模型

A 3D Quantification Technique for Liver Fat Fraction Distribution Analysis Using Dixon Magnetic Resonance Imaging

This study presents a 3D quantification methodology for the distribution of liver fat fraction (LFF) through the utilization of Dixon MRI image analysis. The central aim is to offer a highly accurate and non-invasive means of evaluating liver fat content. The process involves the acquisition of In-phase and Water-phase images from a Dixon sequence. LFF maps are then meticulously computed voxel by voxel by dividing the Lipid Phase images by the In-phase images. Simultaneously, 3D liver contours are extracted from the In-phase images. These crucial components are seamlessly integrated to construct a comprehensive 3D-LFF distribution model. This technique is not limited to healthy livers but extends to those afflicted by hepatic steatosis. The results obtained demonstrate the remarkable effectiveness of this approach in both visualizing and quantifying liver fat content. It distinctly discerns patterns that differentiate between normal and steatotic livers. By harnessing Dixon MRI to extract the 3D structure of the liver, this method offers precise LFF assessments spanning the entirety of the organ, thereby holding great promise for the diagnosis of hepatic steatosis with remarkable effectiveness.

作者聚焦：一种使用 3D Dixon MRI 评估和区分肝脏脂肪模式的非侵入性工具 

This study introduces a unique 3D quantification method for liver fat fraction (LFF) distribution using Dixon Magnetic Resonance Imaging (Dixon MRI). LFF maps, derived from in-phase and water-phase images, are integrated with 3D liver contours to differentiate LFF patterns between normal and steatotic livers, enabling precise assessment of liver fat content.

使用Dixon磁共振成像分析肝脏脂肪分数分布的3D定量技术

This study presents a 3D quantification methodology for the distribution of liver fat fraction (LFF) through the utilization of Dixon MRI image analysis. ...

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

摘要

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使用压痕和磁共振弹性成像对软组织模拟明胶模型进行粘弹性表征

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使用Dixon磁共振成像分析肝脏脂肪分数分布的3D定量技术