这项工作得到了来自尤尼斯国家儿童健康和人类发展研究所的赠款, 赠款编号 R01 HD081123-01A1。Anuj Pareek 是丹麦奥胡斯大学医院放射学系的访问学者。作者承认技术专家黎明华立和苛刻的甘地从宠物/mri 代谢服务中心为他们的协助, 获取 pet/mri 扫描。我们感谢 Daldrup 连接实验室的成员、PET/MRI 服务中心、斯坦福大学的分子成像项目、放射科学实验室、儿科放射科、斯坦福癌症研究所和露西尔的儿科肿瘤学小组。儿童医院为这个项目提供有益的讨论和支持。

这里介绍的所有方法都是根据斯坦福大学机构审查委员会批准的一项研究报告建立的。ferumoxytol 的 "标签" 使用是在调查员发起的研究新药应用 (工业 111154) 下进行的。
1. 在 PET/MRI 扫描前24小时: 患者安全检查
<ol>
	<li>使用 MRI 安全问卷对患者进行潜在磁场危险的筛网。如果对静脉磁共振造影剂的管理进行计划, 检查禁忌症, 如过敏史和肾脏功能, 等等。</li>
	<li>在扫描前告知患者目的、程序、风险和利益。</li>
	<li>称患者为示和造影剂剂量的计算。</li>
	<li>要求患者在扫描前至少4小时禁食。</li>
</ol>
2. 在 PET/MRI 扫描前1-2 小时: 患者准备
<ol>
	<li>请病人取出所有金属物品, 换上礼服。如果有任何植入的金属物体, 确保他们是安全的 MRI 扫描。根据需要使用金属探测器。如果有病人的安全问题, 不要执行 PET/MRI。</li>
	<li>将静脉输液线放置在周围浅静脉内或进入导管。</li>
	<li>稀释 ferumoxytol (5 毫克 Fe/千克体重) 1:4 在盐水中, 并慢慢地注入至少15分钟根据 FDA 协议10。 注: Ferumoxytol 可以使用 "关闭标签" 作为造影剂, 通过研究人员启动的工业, 因为它提供了长期持续的血管和组织增强的整个扫描。或者, 循环钆螯合物可以在 PET/MRI 扫描开始前直接进行。对于肝损害患者, 可选择 gadoxetate 钠。</li>
	<li>用血糖检查病人的血糖水平。如果病人的血糖水平高于200毫克/dL, 考虑重新的 PET/MRI 扫描。</li>
	<li>在 PET/MRI 扫描前45分钟, 管理 2-脱氧-2-(18f) 氟-d-葡萄糖 (18f), 在2毫升的剂量为 1 MBq/千克体重, 通过静脉线。</li>
</ol>
3. 宠物/MR 图像采集
注: 对于本协议, 我们使用了3.0 特斯拉 GE 信号集成 PET/MRI 系统捆绑 MP24_R03 扫描仪软件。
<ol>
	<li>在扫描仪上保存全身扫描 (表 1) 和局部肿瘤扫描 (表 2) 的协议, 这样就可以轻松地检索这些程序, 而不会丢失大量的时间来搜索序列或调整协议。</li>
	<li>对于淋巴瘤患者, 根据临床肿瘤学家的要求, 只规定全身扫描, 无论是从头到脚, 还是从头部延伸到大腿水平。对所有其他病人, 规定全身扫描从头到脚后, 一个单独的局部肿瘤扫描。
	<ol>
		<li>如果肿瘤已经适当地集中在一个全身 PET 板, 规定和运行的专用 MRI 序列在整个身体扫描, 以节省时间;例如, 可以用全身线圈扫描腹部肿瘤。</li>
	</ol>
	</li>
	<li>为了便于对放射科医生的 PET/MRI 数据进行检索和检查, 请将 "诊断" 图像保存在一个加入号码下。稍后 (参见步骤 4.3.5) 将源图像保存在 PACS 系统的第二个加入号码下。</li>
	<li>在扫描过程中使用相同的本地化, 确保患者在扫描期间不会移动。这使得 co-registration 获得的 PET 和 MRI 数据后。</li>
	<li>在每个 PET 板中规定必要的 MRI 序列。综合 pet/mri 系统, 然后允许同时获取 pet 数据和 mri 数据。</li>
	<li>在进入扫描仪室前要求病人直接失效。</li>
	<li>全身 PET/MRI 扫描
	<ol>
		<li>将病人放在 PET/MRI 表上仰卧位。如果患者不能仰卧, 则扫描头部仰卧和全身俯卧位。对于非常高的病人, 在第二步获得小腿。对于有骨或软组织肉瘤的患者, 一定要从关节到关节 (例如, 从髋关节到膝关节的整个股骨) 覆盖整个受影响的骨骼。</li>
		<li>在病人周围关闭一条呼吸带。然后定位头部线圈和2-3 表面线圈的颈部, 胸部, 腹部, 骨盆和四肢的病人。</li>
		<li>在三架飞机上获得全身本地化;轴向, 冠状和矢状 (表 1) 使用一般的本地化协议。根据患者身高选择站数。扫描方向可以是从头到脚或脚朝向头部。</li>
		<li>在开始全身扫描之前, 规定整个协议。简化这个过程并使用 pre-saved 的协议, 这样孩子们就不会失去耐心。</li>
		<li>首先规定轴向 PET 板, 使用最大轴向视场 (视, 通常为25厘米) 和3分钟的数据采集。根据病人的大小, 4-5 块板将覆盖头部到大腿和9-10 板将覆盖整个身体。</li>
		<li>在扫描仪软件中, 为 pet 数据启用两个单独的重建: 一个 non-attenuation 校正 (NAC) pet 和一个 MRI 衰减校正 (MAC) pet。使用矩阵大小 192 x 192。使用28子集和2迭代。PET/mri 软件允许对病人, 病人摇篮和专用 mri 线圈的衰减矫正会计, 使用下面的3.7.7 描述的序列。</li>
		<li>用体积采集 (熔岩) sequencefor 衰减校正 (MRAC) 和更高分辨率的熔岩序列来填充每个 pet 板, 以获得18F-葡萄糖 PET 数据的解剖 co-registration。可以将扩散加权图像 (DWI) 添加为适当的 (表 1)。</li>
		<li>在任务菜单中, 选择宠物任务, 单击添加任务, 单击添加后处理, 选择MRAC Autobind (用户) , 然后单击设置, 这将带来额外的菜单。为 PET 板选择所有连续的水 MRAC, 然后单击接受。这将使软件自动合并 MRAC。</li>
		<li>应用类似的步骤合并 DWI。在这种情况下, 选择第一个 PET 板, 并点击 DWI 序列。然后单击添加任务, 并按照3.7.8 中的相同附加步骤进行操作。</li>
		<li>添加专用 T2-sequence, 用于评估肺部和/或纵隔 (表 1)。</li>
	</ol>
	</li>
	<li>局部 PET/MRI 扫描
	<ol>
		<li>安置一个适当的线圈在主要肿瘤。对于四肢肿瘤, 可以使用 flex 线圈。</li></ol></li></ol>对于骨肿瘤, 确保覆盖邻近关节 (例如, 对于股骨远端骺骨肉瘤, 包括股骨远端骨骺和膝关节)。对于颈部、胸部、腹部和骨盆的原发性肿瘤, 可立即进行局部肿瘤的线圈放置和全身分期 (见步骤 3.7.2)。独立的材料/设备列表提供了扫描仪上可用的与 PET 兼容的 MRI 线圈的概述。
	
	

4. 图像数据处理
注: 要获得合并的全身 PET/MRI 扫描, 以下四步骤必须完成: 1) 重建 pet 图像数据, 2) 将单个 mri 数据合并到单个图像量, 3) co-register pet 到 mri 数据, 4) 生成 pet 全身最大强度投影 (MIP)。扫描仪软件大大简化了这些步骤。
<ol>
	<li>单个 MRI 数据的合并
	<ol>
		<li>选择特定序列的所有单独的 MRI 数据集,例如,熔岩1到 9, 然后按 Autobind按钮。然后, 该软件构建一个合并的 MRI 数据集。保存合并的 MRI 数据集。软件自动命名数据集并将其添加到系列列表中。</li>
	</ol>
	</li>
	<li>PET 和 MRI 数据的联合登记
	<ol>
		<li>要 co-register 合并的 MAC PET 数据和合并的熔岩数据, 请选择需要 co-registered 的每个数据集, 然后按ImageQC按钮。然后, 该软件在六独立的窗口中显示了单个不注册的数据集和两个平面中的 co-registered 数据集。</li>
		<li>正确选择 MRI 数据和窗口级别, 因为一旦 co-registered 扫描完成并保存后, 就无法对其进行调整。</li>
		<li>同样选择 co-registered pet/MRI 数据集和窗口级的 pet 数据。还可以在保存前调整 co-registered 数据的不透明度、缩放和位置。</li>
		<li>为 co-registered 数据集选择适当的切片方向,即、轴向或日冕。</li>
		<li>最后, 保存调整后的 co-registered PET/MRI 数据集:<ol>
			<li>在 "胶片/保存" 菜单中选择批次。选择循环并滚动到最颅骨切片, 然后单击设置开始, 然后向下滚动到最尾部的切片, 然后单击设置结束。</li>
			<li>在 "说明" 字段中, 选择适当的文件名。使用一致且易于识别的所有研究的文件名, 以便放射科医生和临床医师可以很容易地找到特定的数据集 (例如, PET-熔岩全身)。</li>
			<li>单击预览, 并让扫描从头部到脚趾, 同时检查最终的结果是可接受的, 从融合的准确性和窗口水平。关闭预览, 然后选择确定开始呈现 PET/MRI 扫描。渲染过程可以遵循的观察图像索引跟踪栏。</li>
		</ol>
		</li>
		<li>按照同样的步骤, co-register 的 MAC PET 数据和专用的 T2 磁共振成像序列评估肺部。由于 PET 数据视扩展到 MRI 之外, 所以将扫描的开始和结束设置为仅包含 co-registered 部分。 注: 本地 PET/MRI 可以 co-registered 相同的步骤。</li>
	</ol>
	</li>
	<li>生成 PET 全身 MIP 概述
	<ol>
		<li>要生成 pet 的全身最大强度投影 (MIP), 请选择 MAC pet 和任何 MRI 数据集, 然后按ImageQC按钮。</li>
		<li>双击只带有 PET 数据的窗口, 然后将光标悬停在左上角以选择 "查看类型", 然后选择VR。这将创建一个3D 的 PET 数据重建。再次, 将鼠标悬停在左上角以选择渲染模式, 然后选择HD mip , 最终创建 PET 全身 mip 概述。</li>
		<li>要保存 MIP 概述, 请在胶片/保存菜单中选择批次, 然后选择旋转。将图像数调整到60。在 "说明" 字段中选择适当的文件名。单击预览并检查最终结果是否可以接受。关闭预览, 然后选择确定开始呈现 MIP 概述。在退出之前, 请确保呈现完成。</li>
		<li>通过选择相应的系列并在 "目标" 菜单中单击所需的网络, 将诊断图像数据集发送到机构图片存档和通信系统 (PACS)。</li>
		<li>要在不同的加入号码下保存源图像, 请单击编辑患者并更改加入号码。然后重复发送过程。</li>
	</ol>
	</li>
</ol>
5. 图像分析和 SUV 测量
<ol>
	<li>在 FDA 批准的医学成像查看器中加载 co-registered PET/MRI 数据以读取和分析扫描。商业 PET/MRI 观众允许测量的最大标准摄取值 (SUV) 在3D。 注意: 对于这个特定的协议, 我们使用 MIM 版本6.6。</li>
	<li>从工具栏中选择计算 SUV 统计。将感兴趣的区域 (ROI) 放置在 co-registered PET/MRI 上的病理性18F-葡萄糖摄取的组织周围。通过按住鼠标右键并拖动, 可以扩大 ROI 直径。该软件将确定平均和最大 SUV 值。对于淋巴瘤患者, 测量肝和纵隔血池作为参考标准。按照机构特定的准则报告 SUV 测量。</li>
</ol>

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作者没有什么可透露的。

我们已经为儿科癌症患者的 PET/MRI 研究显示了一个 step-by 步骤的协议。该协议最关键的部分是时间规划和处方的 PET 板和 MRI 序列的正确参数和正确的连续顺序, 然后启动全身扫描。这可以使整个身体持续获得。有效的扫描是特别重要的儿科设置, 在那里下患者可以很容易失去耐心, 要么开始移动或中止考试, 如果它需要太长时间。因此, 重要的是要仔细选择扫描方向 (从头或...

集成正电子发射断层扫描 (PET)/磁共振成像 (MRI) 使癌症分期和治疗监测高灵敏度, 高软组织对比度, 并增加代谢信息1,2,3,4. 在成年患者中, pet/MRI 对已建立的癌症分期进行了同样好的 pet/CT 检查5,6,7。在未来, 液体活检可能会导致早期发现癌症的发展 (例如, 通过转录和循环 DNA), 并要求更敏感的成像测试比目前可找到的小肿瘤在体内8.这可能会把 PET/磁共振成像的优势, 以评估整个身体和检测癌症的解剖领域, 已经被经典的 mri 评估单独的, 如大脑, 颈部, 腹部/骨盆, 和肌肉骨骼系统。
对于儿科患者, pet/mri 有几个优势超过 pet/CT: 首先, pet/mri 提供了明显减少的辐射暴露的病人高达 74%4。这可以通过使用电离无辐射的 MRI 代替 CT 技术来实现 PET 数据的解剖 co-registration。此外, 在 MRI 扫描过程中, 现代 pet 检测系统9和更长的 pet 数据获取的灵敏度提高, 使管理的示剂量比当前的 pet/CT 协议4显著减少30-50%。第二, 将原发肿瘤和全身的分期扫描结合起来的可能性, 可以节省时间, 避免某些患者, 如骨和软组织肉瘤患者的重复 sedations。然而, 只有当所有的 PET/MRI 数据 (局部肿瘤和全身) 能够有效地获得, 并且如果结果图像数据的丰度以易于理解的形式呈现给放射学家时, "一站式" 分期扫描才会是临床可行的。在这里提出的协议将提供 step-by 的指示, 获取 PET/MRI 数据, 可用于临床分期的儿童癌症, 特别注意儿科人口的特殊需要。

<table><tbody><tr><td>&lt;strong&gt;Integrated PET/MRI scanner&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>SIgna PET/MR</td><td>GE</td><td></td><td>3.0 T integrated PET/MRI scanner</td></tr><tr><td>&lt;strong&gt;Software&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>MP24_R03</td><td>GE</td><td></td><td>PET/MRI scanner software</td></tr><tr><td>MIM software version 6.6.13</td><td>MIM Software Inc.</td><td></td><td>PET/MRI analysis software</td></tr><tr><td>&lt;strong&gt;Contrast Agents&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Ferumoxytol</td><td>AMAG Pharmaceuticals</td><td></td><td>Iron Oxide nanoparticles</td></tr><tr><td>18F-FDG</td><td>-</td><td></td><td>2-Deoxy-2-(18F)fluoro-D-glucose</td></tr><tr><td>&lt;strong&gt;MRI coils available on the scanner&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Nova 32 Channel Head coil</td><td>Nova&amp;nbsp;</td><td></td><td></td></tr><tr><td>Neocoil 1H 16 channel GEM Flex Large Array</td><td>GE</td><td>M7000SK</td><td></td></tr><tr><td>Neocoil 1H 16 channel &amp;nbsp;GEM Flex Medium Array</td><td>GE</td><td>M7000SL</td><td></td></tr><tr><td>Neocoil 1H 16 channel GEM Flex Small Array</td><td>GE</td><td>M7000SM</td><td></td></tr><tr><td>Everest Central Molecular Imaging Array (CMA)</td><td>GE</td><td>M8000RB</td><td></td></tr><tr><td>Everest Head Neck Unit</td><td>GE</td><td>M8000CB</td><td></td></tr><tr><td>Everest Lower and Upper Anterior Array</td><td>GE</td><td>M8000CC &amp;amp; M8000CA</td><td></td></tr><tr><td>Invivo 1H 8 channel High Res Brain Array</td><td>GE</td><td>M8000RA</td><td></td></tr><tr><td>3.0T HD Breast Array Coil</td><td>GE</td><td>M7000GG</td><td></td></tr><tr><td>3.0T Split-Top Head TR Single Ch Coil</td><td>GE</td><td>G6000BH</td><td></td></tr></tbody></table>

whole-body pet/mri of pediatric patients: the details that matter

综合 PET/MRI 是一种混合成像技术, 使临床医生获得诊断图像的肿瘤评估和治疗监测与高软组织对比度和增加代谢信息。综合 PET/磁共振成像已证明是有价值的临床设置和有许多有前途的未来应用。在这里提出的协议将提供 step-by 步骤的指示, 获取全身 2-脱氧-2-(18f) 氟-d-葡萄糖 (18f 葡萄糖) PET/MRI 数据的儿童癌症。它还提供了有关如何将全身分期扫描与局部肿瘤扫描结合以评估原发肿瘤的说明。该协议的重点是全面和时间, 这是两个普遍需要的临床应用。本协议最初是为6岁以上的儿童开发的, 或年龄足以遵守呼吸控制指令, 但也可以应用于全身麻醉患者。同样, 这个协议可以被修改, 以适应机构偏好的选择磁共振脉冲序列的全身扫描和局部肿瘤评估。

我们展示了一个完整的全身 (从头到脚) 数据集的 MRI, pet 和融合宠物/mr 图像分别, 分别为 10 year-old 男孩与状态后切除的无差别肉瘤的第十二肋骨, 谁提出与肺部和 心脏转移 (图 1)。此处显示的数据集是在40分钟内获得的。在这次考试中, 病人的有效剂量是 3.3 mSv11。
对于接受主肿瘤的专门扫描的患者, 除了全身从头的 PET/磁共?...

Watch this Scientific Journal Video about Whole-body PET/MRI of Pediatric Patients: The Details That Matter at JoVE.com

Whole-body PET/MRI of Pediatric Patients: The Details That Matter

本文提供了全面的 step-by 步骤的指示, 获取全身 2-脱氧-2-(18f) 氟-d-葡萄糖 (18f 葡萄糖) PET/MRI 扫描的癌症分期儿科患者。该协议是为6岁以上的儿童, 或年龄足以遵守呼吸保持指示, 但也可以用于一般麻醉病人。

儿科患者全身 PET/MRI: 物质的细节

Integrated PET/MRI is a hybrid imaging technique enabling clinicians to acquire diagnostic images for tumor assessment and treatment monitoring with both ...

whole-body-petmri-of-pediatric-patients-the-details-that-matter

Research

JoVE Journal

Cancer Research

14.4K 次观看.  Stanford University. 本文提供了全面的 step-by 步骤的指示, 获取全身 2-脱氧-2-(18f) 氟-d-葡萄糖 (18f 葡萄糖) PET/MRI 扫描的癌症分期儿科患者。该协议是为6岁以上的儿童, 或年龄足以遵守呼吸保持指示, 但也可以用于一般麻醉病人。

视频: Whole-body PET/MRI of Pediatric Patients: The Details That Matter

PET and MRI Guided Irradiation of a Glioblastoma Rat Model Using a Micro-irradiator

For decades, small animal radiation research was mostly performed using fairly crude experimental setups applying simple single-beam techniques without the ability to target a specific or well-delineated tumor volume. The delivery of radiation was achieved using fixed radiation sources or linear accelerators producing megavoltage (MV) X-rays. These devices are unable to achieve sub-millimeter precision required for small animals. Furthermore, the high doses delivered to healthy surrounding tissue hamper response assessment. To increase the translation between small animal studies and humans, our goal was to mimic the treatment of human glioblastoma in a rat model. To enable a more accurate irradiation in a preclinical setting, recently, precision image-guided small animal radiation research platforms were developed. Similar to human planning systems, treatment planning on these micro-irradiators is based on computed tomography (CT). However, low soft-tissue contrast on CT makes it very challenging to localize targets in certain tissues, such as the brain. Therefore, incorporating magnetic resonance imaging (MRI), which has excellent soft-tissue contrast compared to CT, would enable a more precise delineation of the target for irradiation. In the last decade also biological imaging techniques, such as positron emission tomography (PET) gained interest for radiation therapy treatment guidance. PET enables the visualization of e.g., glucose consumption, amino-acid transport, or hypoxia, present in the tumor. Targeting those highly proliferative or radio-resistant parts of the tumor with a higher dose could give a survival benefit. This hypothesis led to the introduction of the biological tumor volume (BTV), besides the conventional gross target volume (GTV), clinical target volume (CTV), and planned target volume (PTV).
At the preclinical imaging lab of Ghent University, a micro-irradiator, a small animal PET, and a 7 T small animal MRI are available. The goal was to incorporate MRI-guided irradiation and PET-guided sub-volume boosting in a glioblastoma rat model.

In the past, small animal irradiation was usually performed without the ability to target a well-delineated tumor volume. The goal was to mimic the treatment of human glioblastoma in rats. Using a small animal irradiation platform, we performed MRI-guided 3D conformal irradiation with PET-based sub-volume boosting in a preclinical setting.

PET 与 MRI 引导下微器对大鼠胶质瘤模型的照射

For decades, small animal radiation research was mostly performed using fairly crude experimental setups applying simple single-beam techniques without ...

科研

癌症研究

Making MR Imaging Child's Play - Pediatric Neuroimaging Protocol, Guidelines and Procedure

Within the last decade there has been an increase in the use of structural and functional magnetic resonance imaging (fMRI) to investigate the neural basis of human perception, cognition and behavior 1, 2. Moreover, this non-invasive imaging method has grown into a tool for clinicians and researchers to explore typical and atypical brain development. Although advances in neuroimaging tools and techniques are apparent, (f)MRI in young pediatric populations remains relatively infrequent 2. Practical as well as technical challenges when imaging children present clinicians and research teams with a unique set of problems 3, 2. To name just a few, the child participants are challenged by a need for motivation, alertness and cooperation. Anxiety may be an additional factor to be addressed. Researchers or clinicians need to consider time constraints, movement restriction, scanner background noise and unfamiliarity with the MR scanner environment2,4-10. A progressive use of functional and structural neuroimaging in younger age groups, however, could further add to our understanding of brain development. As an example, several research groups are currently working towards early detection of developmental disorders, potentially even before children present associated behavioral characteristics e.g.11. Various strategies and techniques have been reported as a means to ensure comfort and cooperation of young children during neuroimaging sessions. Play therapy 12, behavioral approaches 13, 14,15, 16-18 and simulation 19, the use of mock scanner areas 20,21, basic relaxation 22 and a combination of these techniques 23 have all been shown to improve the participant's compliance and thus MRI data quality. Even more importantly, these strategies have proven to increase the comfort of families and children involved 12. One of the main advances of such techniques for the clinical practice is the possibility of avoiding sedation or general anesthesia (GA) as a way to manage children's compliance during MR imaging sessions 19,20. In the current video report, we present a pediatric neuroimaging protocol with guidelines and procedures that have proven to be successful to date in young children.

Despite an increase in the use of structural and functional magnetic resonance imaging (fMRI) in humans, the study of young pediatric populations remains a challenge. We present a hands-on, step-by-step video protocol including guidelines for clinicians and researchers intending to perform (f)MRI in young children.

使磁共振成像儿戏 - 小儿神经影像学的协议，指引及程序

Within the last decade there has been an increase in the use of structural and functional magnetic resonance imaging (fMRI) to investigate the neural ...

生物学

MRI and PET in Mouse Models of Myocardial Infarction

Myocardial infarction is one of the leading causes of death in the Western world. The similarity of the mouse heart to the human heart has made it an ideal model for testing novel therapeutic strategies.
In vivo magnetic resonance imaging (MRI) gives excellent views of the heart noninvasively with clear anatomical detail, which can be used for accurate functional assessment. Contrast agents can provide basic measures of tissue viability but these are nonspecific. Positron emission tomography (PET) is a complementary technique that is highly specific for molecular imaging, but lacks the anatomical detail of MRI. Used together, these techniques offer a sensitive, specific and quantitative tool for the assessment of the heart in disease and recovery following treatment.
In this paper we explain how these methods are carried out in mouse models of acute myocardial infarction. The procedures described here were designed for the assessment of putative protective drug treatments. We used MRI to measure systolic function and infarct size with late gadolinium enhancement, and PET with fluorodeoxyglucose (FDG) to assess metabolic function in the infarcted region. The paper focuses on practical aspects such as slice planning, accurate gating, drug delivery, segmentation of images, and multimodal coregistration. The methods presented here achieve good repeatability and accuracy maintaining a high throughput.

We describe how to perform MRI and PET imaging of the mouse heart. The protocol is tailored to assess treatment efficacy in models of myocardial infarction and heart failure.

MRI和PET心肌梗死小鼠模型

Myocardial infarction is one of the leading causes of death in the Western world. The similarity of the mouse heart to the human heart has made it an ...

医学

A Dual Tracer PET-MRI Protocol for the Quantitative Measure of Regional Brain Energy Substrates Uptake in the Rat

We present a method for comparing the uptake of the brain&#39;s two key energy substrates: glucose and ketones (acetoacetate [AcAc] in this case) in the rat. The developed method is a small-animal positron emission tomography (PET) protocol, in which&#160;11C-AcAc and 18F-fluorodeoxyglucose (18F-FDG) are injected sequentially in each animal. This dual tracer PET acquisition is possible because of the short half-life of 11C (20.4 min). The rats also undergo a magnetic resonance imaging (MRI) acquisition seven days before the PET protocol. Prior to image analysis, PET and MRI images are coregistered to allow the measurement of regional cerebral uptake (cortex, hippocampus, striatum, and cerebellum). A quantitative measure of 11C-AcAc and 18F-FDG brain uptake (cerebral metabolic rate; &#956;mol/100 g/min) is determined by kinetic modeling using the image-derived input function (IDIF) method. Our new dual tracer PET protocol is robust and flexible; the two tracers used can be replaced by different radiotracers to evaluate other processes in the brain. Moreover, our protocol is applicable to the study of brain fuel supply in multiple conditions such as normal aging and neurodegenerative pathologies such as Alzheimer&#39;s and Parkinson&#39;s diseases.

Small-animal positron emission tomography enables the assessment of the brain&#39;s two main energy substrates:&#160;glucose and ketones. In the present method, 11C-acetoacetate and 18F-fluorodeoxyglucose are injected sequentially in each animal, and their uptake is measured quantitatively in specific brain regions determined from the magnetic resonance images.

We present a method for comparing the uptake of the brain&#39;s two key energy substrates: glucose and ketones (acetoacetate [AcAc] in this case) in the ...

神经科学

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 ...

Dynamic Contrast Enhanced Magnetic Resonance Imaging of an Orthotopic Pancreatic Cancer Mouse Model

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been limitedly used for orthotopic pancreatic tumor xenografts due to severe respiratory motion artifact in the abdominal area. Orthotopic tumor models offer advantages over subcutaneous ones, because those can reflect the primary tumor microenvironment affecting blood supply, neovascularization, and tumor cell invasion. We have recently established a protocol of DCE-MRI of orthotopic pancreatic tumor xenografts in mouse models by securing tumors with an orthogonally bent plastic board to prevent motion transfer from the chest region during imaging. The pressure by this board was localized on the abdominal area, and has not resulted in respiratory difficulty of the animals. This article demonstrates the detailed procedure of orthotopic pancreatic tumor modeling using small animals and DCE-MRI of the tumor xenografts. Quantification method of pharmacokinetic parameters in DCE-MRI is also introduced. The procedure described in this article will assist investigators to apply DCE-MRI for orthotopic gastrointestinal cancer mouse models.

The goal of this protocol is to apply dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) for orthotopic pancreatic tumor xenografts in mice. DCE-MRI is a non-invasive method to analyze microvasculature in a target tissue, and useful to assess vascular response in a tumor following a novel therapy.

原位胰腺癌小鼠模型的动态对比增强磁共振成像

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been limitedly used for orthotopic pancreatic tumor xenografts due to severe ...

Simultaneous PET/MRI Imaging During Mouse Cerebral Hypoxia-ischemia

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics disturbance in affected cells. Diffusion weighted magnetic resonance imaging (MRI) identifies regions that are damaged, potentially irreversibly, by hypoxia-ischemia. Alterations in glucose utilization in the affected tissue may be detectable by positron emission tomography (PET) imaging of 2-deoxy-2-(18F)fluoro-&#7429;-glucose ([18F]FDG) uptake. Due to the rapid and variable nature of injury in this animal model, acquisition of both modes of data must be performed simultaneously in order to meaningfully correlate PET and MRI data. In addition, inter-animal variability in the hypoxic-ischemic injury due to vascular differences limits the ability to analyze multi-modal data and observe changes to a group-wise approach if data is not acquired simultaneously in individual subjects. The method presented here allows one to acquire both diffusion-weighted MRI and [18F]FDG uptake data in the same animal before, during, and after the hypoxic challenge in order to interrogate immediate physiological changes.

The method presented here uses simultaneous positron emission tomography and magnetic resonance imaging. In the cerebral hypoxia-ischemia model, dynamic changes in diffusion and glucose metabolism occur during and after injury. The evolving and irreproducible damage in this model necessitates simultaneous acquisition if meaningful multi-modal imaging data are to be acquired.

同时PET / MRI成像在小鼠脑缺氧缺血

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics ...

Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular mechanisms responsible for the disease, and are very convenient for rapid drug screening and testing of promising therapies. A limiting factor in these studies is often the lack of efficient non-invasive methods for sequentially analyzing the anatomical and functional changes in the kidney. Magnetic resonance imaging (MRI) is the current gold standard imaging technique to follow autosomal dominant polycystic kidney disease (ADPKD) patients, providing excellent soft tissue contrast and anatomic detail and allowing Total Kidney Volume (TKV) measurements.A major advantage of MRI in rodent models of PKD is the possibility for in vivo imaging allowing for longitudinal studies that use the same animal and therefore reducing the total number of animals required. In this manuscript, we will focus on using Ultra-high field (UHF) MRI to non-invasively acquire in vivo images of rodent models for PKD. The main goal of this work is to introduce the use of MRI as a tool for in vivo phenotypical characterization and drug monitoring in rodent models for PKD.

Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

The use of ultra-high field MRI as a non-invasive way to obtain phenotypic information of rodent models for polycystic kidney disease and to monitor interventions is described. Compared with the traditional histological approach, MRI images can be acquired in vivo, allowing for longitudinal follow-up.

在多囊肾小型啮齿动物模型采用超高场磁共振成像<em&gt;在体内</em&gt;表型和药物监测

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular ...

Functional Imaging of Brown Fat in Mice with 18F-FDG micro-PET/CT

Brown adipose tissue (BAT) differs from white adipose tissue (WAT) by its discrete location and a brown-red color due to rich vascularization and high density of mitochondria. BAT plays a major role in energy expenditure and non-shivering thermogenesis in newborn mammals as well as the adults 1. BAT-mediated thermogenesis is highly regulated by the sympathetic nervous system, predominantly via &beta; adrenergic receptor 2, 3. Recent studies have shown that BAT activities in human adults are negatively correlated with body mass index (BMI) and other diabetic parameters 4-6. BAT has thus been proposed as a potential target for anti-obesity/anti-diabetes therapy focusing on modulation of energy balance 6-8. While several cold challenge-based positron emission tomography (PET) methods are established for detecting human BAT 9-13, there is essentially no standardized protocol for imaging and quantification of BAT in small animal models such as mice. Here we describe a robust PET/CT imaging method for functional assessment of BAT in mice. Briefly, adult C57BL/6J mice were cold treated under fasting conditions for a duration of 4 hours before they received one dose of 18F-Fluorodeoxyglucose (FDG). The mice were remained in the cold for one additional hour post FDG injection, and then scanned with a small animal-dedicated micro-PET/CT system. The acquired PET images were co-registered with the CT images for anatomical references and analyzed for FDG uptake in the interscapular BAT area to present BAT activity. This standardized cold-treatment and imaging protocol has been validated through testing BAT activities during pharmacological interventions, for example, the suppressed BAT activation by the treatment of &beta;-adrenoceptor antagonist propranolol 14, 15, or the enhanced BAT activation by &beta;3 agonist BRL37344 16. The method described here can be applied to screen for drugs/compounds that modulate BAT activity, or to identify genes/pathways that are involved in BAT development and regulation in various preclinical and basic studies.

Functional Imaging of Brown Fat in Mice with 18F-FDG micro-PET/CT

A method of functional imaging of mouse brown adipose tissue (BAT) is described in which cold-stimulated uptake of 18F-Fluorodeoxyglucose (FDG) in BAT is non-invasively assessed with a standardized micro-PET/CT protocol. This method is robust and sensitive to detect differences in BAT activities in mouse models.

功能成像在小鼠体内的棕色脂肪与FDG micro-PET/CT

Brown adipose tissue (BAT) differs from white adipose  tissue (WAT) by its discrete location and a brown-red color due to rich  vascularization and high ...

Clinical Indications for Rapid Sequence MRI in Pediatric Neurosurgical Patients and the Limitations and Barriers to Implementation

Rapid and fast magnetic resonance imaging (MRI) protocols have become increasingly popular for pediatric neurosurgical patients as they are a great way to reduce ionizing radiation and sedation. While their popularity has increased, there are hurdles to overcome when transitioning to using them clinically, such as cost, staffing training, and motion artifact. Through this paper, we developed a protocol for clinical applications where rapid MRI can be a substitute or adjuvant in diagnostic workup. Further, we outline the relevant literature for the use of RS-MRI for the spine, TBI, and hydrocephalus pathologies while expanding upon the limitations and logistical barriers when transitioning to their use, a few of which are discussed above. Through this, we conclude that RS-MRI can be used diagnostically for spinal pathologies such as syrinx and hydrocephalus. Further, its lack of sensitivity for TBI findings makes rapid sequence magnetic resonance imaging (RS-MRI) a strong adjuvant with other advanced imaging or computed tomography (CT) for traumatic brain injury (TBI) pathologies.

<meta charset="utf8"></head><body>小儿神经外科患者快速序列 MRI 的临床适应证及其实施的局限性和障碍

Here, we present a protocol to increase the use of rapid sequence magnetic resonance imaging (RS-MRI) for pediatric patients for spine, traumatic brain injury (TBI), and hydrocephalus while documenting limitations and barriers to universal implementation.

小儿神经外科患者快速序列 MRI 的临床适应证及其实施的局限性和障碍

Rapid and fast magnetic resonance imaging (MRI) protocols have become increasingly popular for pediatric neurosurgical patients as they are a great way to ...