这项工作得到了台湾科学技术部授予的 MOST-105-2314-B-039-044-MY2 的赠款支持。

中国医科大学的机构护理和使用委员会 (IACUC) 批准了所有的程序。
1. 动物准备和监测
<ol><li>在开始进行 MRI 扫描的动物准备之前, 在扫描仪室外留下所有磁性敏感物品, 如钱包、钥匙、信用卡等。</li>
	<li>最初麻醉鼠 (2 月大的雄性大 (SD) 鼠, 280–350 g) 在一个感应箱中使用5% 异氟醚 (ISO) 和氧气 (2 升/分钟) 的混合物, 为3–5分钟, 必要时。</li>
	<li>当动物处于卧位时, 没有对尾巴或脚趾捏的反应, 停止 ISO 管理并将动物转移到扫描室。</li>
	<li>把老鼠放在 MRI 床上, 头先俯卧, 并通过鼻锥装置提供 2-3% ISO 以维持麻醉。</li>
	<li>通过在动物躯干下放置呼吸枕传感器来监测呼吸。</li>
	<li>将传感器连接到呼吸系统, 并检查每分钟40-50 次 (bpm) 的呼吸速率。</li>
	<li>用于电影门控的 PC MRI 采集, 分别在右侧前爪和左后爪上放置一个电极 (图 1a)。</li>
	<li>将心电图 (ECG) 电缆拧在一起。</li>
	<li>使用带有耳棒和咬条的头持有人来保护动物以限制头部运动。</li>
	<li>使用暖空气加热系统或纱布垫保持体温, 而在磁铁。</li>
	<li>确保心电图显示器上的 R 波清晰 (图 1b), 并将该动物放在扫描仪中。没有必要将表面线圈放置在动物颈部的顶端, 因为图像是由卷线圈获取的。</li>
</ol>2. MRI 采集
<ol><li>使用 2–3% ISO 在整个成像过程中保持麻醉。持续监测生理反应, 尽可能保持恒定。</li>
	<li>一旦将动物放置在扫描仪内并继续保持生理稳定, 就开始 MRI 扫描。在本研究中, 使用 7 T 小动物 mri 系统的梯度强度为 630 mT/米, 但其他领域的优势, 小动物 MRI 系统可以使用。</li>
	<li>从 MRI 扫描仪的控制台监视器中选择 "定位器"序列, 并使用任何快速的图像采集序列 (如快速旋转回波) 在所有三方向上获取侦察图像, 以创建冠状、轴向和矢状图像。.这些侦察图像的目的是确定成像平面。</li>
	<li>确保动物头部和颈部的中心位于磁铁的中心。如有必要, 调整动物的位置, 直到达到正确的位置。如果动物被重新定位, 重复扫描以获取侦察图像。</li>
	<li>从 MRI 扫描仪的控制台监控器中选择"飞行时间" 序列, 并首先获得2D 的脑血管造影, 以确定共同国家评估的精确解剖位置。使用以下扫描参数: 重复时间 (TR)/回波时间 (TE) = 22/4.87 ms, 翻转角度 = 90°, 视场 (FOV) = 40 x 40 毫米2, 基体大小 = 256 x 256, 切片厚度0.6 毫米, 与励磁的数量 = 1。 注意: 飞行序列的名称可以是特定于供应商的。用户可以在控制台监视器中插入这些参数。</li>
	<li>确保饱和带是 "on", 并放置在顶部, 以避免干扰静脉信号。 注: 对于饱和带, 它通常带有飞行序列。如果显示器上没有显示饱和带, 请通知服务人员。</li>
	<li>在使用飞行后血管造影定位共同国家评估后, 将 PC MRI 的图像平面对准共同国家评估和定向的中心, 使切片垂直于血流方向 (图 2a)。</li>
	<li>确保呼吸和心电门连接到 mri 系统, 显示显示器计算机上的清晰信号 (图 1b), 并将触发模块设置为 "触发模式" , 从 mri 扫描仪的控制台监视器中 "启动"。</li>
	<li>确认动物的生理反应是稳定的, 然后开始从监控计算机的 PC MRI 扫描 (图 1b)。验证显示器计算机和 MRI 扫描仪的控制台监视器中的门选择是否 "on"。 注: 本研究使用的生理学监测系统由供应商提供。对于大多数动物扫描仪, 都提供了类似的生理监测系统和特定的供应商。</li>
	<li>从 mri 扫描仪的控制台显示器上选择 pc mri 序列序列, 并使用以下参数执行门控 pc mri 扫描: tr = 15.55/4.51 ms (最小 TR 和 TE), 翻转 angle=30°, FOV = 40 x 40 毫米2, 矩阵大小 = 192 x 192, 切片厚度 = 2 毫米, 速度编码 (VENC) = 120 厘米/秒, 带 NEX=8。单向 VENC 是通过平面方向获取的。 注: 扫描时间约为8.5 分钟, 但实际扫描时间可能略有不同的动物由于心脏循环的变化。</li>
	<li>重复步骤2.6–2.9 图像获取如果要将感兴趣的区域更改为共同国家评估中的另一个位置, 例如在分岔4中。</li>
	<li>在扫描完成后, 从扫描仪中取出该动物并将其返回到其恢复笼中。</li>
	<li>用暖气灯保暖动物以保持体温。保持灯至少15厘米远离动物, 以防止过热。</li>
	<li>当动物开始移动并表现出对尾巴或脚趾捏的反应时, 关掉暖气灯。</li>
</ol>3. 数据处理
<ol><li>保存数字成像和医学通讯中的 MRI 数据 (DICOM) 格式或任何其他特定于供应商的格式。生成具有两种类型图像的电影系列: 震级图像 (解剖图像) 和相位图像 (图 2b)。 注意: 在某些扫描仪中, 生成了第三种图像, 它可以是震级图像 x 相图或复数差分 (两种不同速度编码梯度的采集之间的复减法)。第三个映像是依赖于供应商的。</li>
	<li>预处理图像数据。将相位图像隐蔽到速度图中, 并更正相位偏移误差5。 注意: 相位图像有一个任意的 mr 单位的信号强度, 而不是真正的速度值, 但 mr 信号强度是线性比例的速度。相位图像的最大 MRI 信号通常被指定为 VENC 的值, 最小信号被分配为 VENC 的相对值。有关 Matlab 脚本的示例, 请参见补充代码文件 1, 然后按 "运行" 按钮。</li>
	<li>通过跟踪共同国家评估的边界, 仔细地描绘 ROI。当动脉在不同的心脏阶段可以扩张和构造时, 为每个时间框架描绘 ROIs。通过对动脉 ROI (即速度 x 区域) 的积分来计算血流量。结果每个动脉的血流都在毫升/秒的单位内。有关 Matlab 脚本的示例, 请参见补充代码文件 2, 然后按 "运行" 按钮。</li>
</ol>

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没有什么可透露的。

MRI 是一种非侵入性和纵向评价血流的综合方法。本文提出了一种用于大鼠共同评价的 PC 磁共振成像的协议。本程序易于在任何动物 MRI 扫描仪中执行, 并显示良好的重现性。
PC MRI 技术在人类10、11以及动物研究中得到了越来越多的普及, 4、12。在这些研究中, 彭等的结果。<sup class="x...

磁共振成像 (MRI) 是一种多功能的方法, 提供了有关内部身体结构和生理学的详细信息, 并越来越多地用于临床诊断和前期动物研究。动物模型是至关重要的, 以更好地了解相当多的临床意义1。由于动物模型在麻醉要求和生理参数方面与人类有很大的不同, 因此对这种动物的 MRI 程序进行优化具有重要意义。
磁共振成像 (mri) 是一种特殊类型的 mri, 利用流动旋转的速度来量化与流动相关的参数, 如血流。借助于 PC MRI, 利用动物模型对主要动脉中的流型进行映射可以帮助揭示心血管病理2。此外, PC MRI 可无创监测病理生理学情况下血液流动的内在变动3。这些观察表明, PC MRI 是一种有价值的方法, 可用于人类心血管疾病的动物模型。
在本报告中, 我们描述了一种定量的血流量在颈总动脉 (共同评估) 的大鼠。两种共同国家评估为头颈部提供含氧血, 颈动脉疾病是中风的主要原因。因此, 检测早期病理在共同国家评估中是至关重要的。这一过程的持续时间约为15分钟, 并可能适用于条件与血流动力学改变, 如动脉粥样硬化或中风。

<table border="0" cellpadding="0" cellspacing="0" width="875">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">7T small animal MRI system</td>
			<td style="width:123px;">Bruker</td>
			<td style="width:344px;"></td>
			<td style="width:193px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Isoflurane&#160;</td>
			<td>Baxter</td>
			<td>1001936040</td>
			<td>anesthetic</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">ECG lead&#160;</td>
			<td>3M</td>
			<td>2269T</td>
			<td style="width:193px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Matlab</td>
			<td>MathWorks</td>
			<td></td>
			<td>sofeware for image processing</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Monitoring and gating system</td>
			<td>SA instruments, Inc</td>
			<td>Model 1030</td>
			<td style="width:193px;"></td>
		</tr>
	</tbody>
</table>

phase contrast magnetic resonance imaging in the rat common carotid artery

相衬磁共振成像 (PC MRI) 是一种无创的方法, 可以量化流量相关参数, 如血流。以前的研究表明, 异常的血流可能与系统性血管危险有关。因此, PC MRI 可以促进从心血管疾病动物模型获得的数据的翻译到相关的临床调查。在本报告中, 我们描述了用电影门控电脑 MRI 测量大鼠颈总动脉血流量的方法, 并讨论了相关的分析方法。这一程序可以在活体, 麻醉动物, 不需要安乐死后的程序。所提出的扫描参数产生可重复测量的血液流量, 表明了优良的重现性的结果。本文所描述的 PC MRI 程序可用于药理试验、病理生理学评估和脑血流动力学评价。

正确的切片几何是确保 PC MRI 实验成功的关键。准确的图像平面定位产生一个 "圆形" 的动脉形状 (图 3a), 随着角度的增加,即, 当它与动脉垂直较少时, 产生的动脉几何变成卵球形, 导致较大的部分体积效果 (图 3b)。严重的局部体积效应会导致对血流的高估6,7。因此, 如果动脉形状...

Watch this Scientific Journal Video about Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery at JoVE.com

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

本程序的总体目标是采用无创相磁共振成像技术对大鼠颈总动脉血流进行测量。

大鼠颈总动脉的相位对比磁共振成像

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous ...

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Research

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Medicine

9.4K 次观看.  Chang Gung Memorial Hospital. 本程序的总体目标是采用无创相磁共振成像技术对大鼠颈总动脉血流进行测量。

视频: Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF. Current technologies for CMR are time consuming and difficult to implement in clinical practice. Feature tracking is a technology that can lead to more automization and robustness of quantitative analysis of medical images with less time consumption than comparable methods.
Methods: An automatic or manual input in a single phase serves as an initialization from which the system starts to track the displacement of individual patterns representing anatomical structures over time. The specialty of this method is that the images do not need to be manipulated in any way beforehand like e.g. tagging of CMR images.
Results: The method is very well suited for tracking muscular tissue and with this allowing quantitative elaboration of myocardium and also blood flow.
Conclusions: This new method offers a robust and time saving procedure to quantify myocardial tissue and blood with displacement, velocity and deformation parameters on regular sequences of CMR imaging. It therefore can be implemented in clinical practice.

An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF.

磁共振衍生的心肌劳损评估使用特征跟踪

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that ...

科研

医学

Training a Sophisticated Microsurgical Technique: Interposition of External Jugular Vein Graft in the Common Carotid Artery in Rats

Neointimal hyperplasia is one the primary causes of stenosis in arterialized veins that are of great importance in arterial coronary bypass surgery, in peripheral arterial bypass surgery as well as in arteriovenous fistulas.1-5 The experimental procedure of vein graft interposition in the common carotid artery by using the cuff-technique has been applied in several research projects to examine the aetiology of neointimal hyperplasia and therapeutic options to address it. 6-8 The cuff prevents vessel anastomotic remodeling and induces turbulence within the graft and thereby the development of neointimal hyperplasia.
Using the superior caval vein graft is an established small-animal model for venous arterialization experiment.9-11 This current protocol refers to an established jugular vein graft interposition technique first described by Zou et al., 9 as well as others.12-14 Nevertheless, these cited small animal protocols are complicated.
To simplify the procedure and to minimize the number of experimental animals needed, a detailed operation protocol by video training is presented. This video should help the novice surgeon to learn both the cuff-technique and the vein graft interposition. Hereby, the right external jugular vein was grafted in cuff-technique in the common carotid artery of 21 female Sprague Dawley rats categorized in three equal groups that were sacrificed on day 21, 42 and 84, respectively. Notably, no donor animals were needed, because auto-transplantations were performed. The survival rate was 100 % at the time point of sacrifice. In addition, the graft patency rate was 60 % for the first 10 operated animals and 82 % for the remaining 11 animals. The blood flow at the time of sacrifice was 8&plusmn;3 ml/min. In conclusion, this surgical protocol considerably simplifies, optimizes and standardizes this complicated procedure. It gives novice surgeons easy, step-by-step instruction, explaining possible pitfalls, thereby helping them to gain expertise fast and avoid useless sacrifice of experimental animals.

Neointimal hyperplasia is the primary cause of stenosis in arterialized veins. We propose a new protocol whereby the right external jugular vein is grafted using the cuff technique in the common carotid artery of Sprague Dawley rats. The survival rate was 100 % at the time point of sacrifice.

培养一个精密的显微外科技术在大鼠颈总动脉，颈外静脉移植:介入

Neointimal hyperplasia is one the primary causes of stenosis in arterialized veins that are of great importance in arterial coronary bypass surgery, in ...

Multi-modal Imaging of Angiogenesis in a Nude Rat Model of Breast Cancer Bone Metastasis Using Magnetic Resonance Imaging, Volumetric Computed Tomography and Ultrasound

Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell proliferation in the bone marrow cavity as well as for interaction of tumor and bone cells resulting in local bone destruction. Our aim was to develop a model of experimental bone metastasis that allows in vivo assessment of angiogenesis in skeletal lesions using non-invasive imaging techniques.
For this purpose, we injected 105 MDA-MB-231 human breast cancer cells into the superficial epigastric artery, which precludes the growth of metastases in body areas other than the respective hind leg1. Following 25-30 days after tumor cell inoculation, site-specific bone metastases develop, restricted to the distal femur, proximal tibia and proximal fibula1. Morphological and functional aspects of angiogenesis can be investigated longitudinally in bone metastases using magnetic resonance imaging (MRI), volumetric computed tomography (VCT) and ultrasound (US).
MRI displays morphologic information on the soft tissue part of bone metastases that is initially confined to the bone marrow cavity and subsequently exceeds cortical bone while progressing. Using dynamic contrast-enhanced MRI (DCE-MRI) functional data including regional blood volume, perfusion and vessel permeability can be obtained and quantified2-4. Bone destruction is captured in high resolution using morphological VCT imaging. Complementary to MRI findings, osteolytic lesions can be located adjacent to sites of intramedullary tumor growth. After contrast agent application, VCT angiography reveals the macrovessel architecture in bone metastases in high resolution, and DCE-VCT enables insight in the microcirculation of these lesions5,6. US is applicable to assess morphological and functional features from skeletal lesions due to local osteolysis of cortical bone. Using B-mode and Doppler techniques, structure and perfusion of the soft tissue metastases can be evaluated, respectively. DCE-US allows for real-time imaging of vascularization in bone metastases after injection of microbubbles7.
In conclusion, in a model of site-specific breast cancer bone metastases multi-modal imaging techniques including MRI, VCT and US offer complementary information on morphology and functional parameters of angiogenesis in these skeletal lesions.

In the pathogenesis of bone metastasis, angiogenesis is a crucial process and therefore represents a target for imaging and therapy. Here, we present a rat model of site-specific breast cancer bone metastasis and describe strategies to non-invasively image angiogenesis in vivo using magnetic resonance imaging, volumetric computed tomography and ultrasound.

利用磁共振成像，容积电脑断层扫描及超音波的裸鼠乳腺癌骨转移大鼠模型血管生成的多模态成像

Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell ...

A Murine Model of Stent Implantation in the Carotid Artery for the Study of Restenosis

Despite the considerable progress made in the stent development in the last decades, cardiovascular diseases remain the main cause of death in western countries. Beside the benefits offered by the development of different drug-eluting stents, the coronary revascularization bears also the life-threatening risks of in-stent thrombosis and restenosis. Research on new therapeutic strategies is impaired by the lack of appropriate methods to study stent implantation and restenosis processes. Here, we describe a rapid and accessible procedure of stent implantation in mouse carotid artery, which offers the possibility to study in a convenient way the molecular mechanisms of vessel remodeling and the effects of different drug coatings.

A model of stent implantation in mouse carotid artery is described. Compared to other similar methods, this procedure is very rapid, simple and accessible, offering the possibility to study in a convenient way the vascular wall reaction to different drug-eluting stents and the molecular mechanisms of restenosis.

颈动脉支架植入再狭窄的研究的小鼠模型

Despite  the considerable progress made in the stent development in the last decades,  cardiovascular diseases remain the main cause of death in western ...

Adult Mouse Venous Hypertension Model: Common Carotid Artery to External Jugular Vein Anastomosis.

The understanding of the pathophysiology of brain arteriovenous malformations and arteriovenous fistulas has improved thanks to animal models. A rat model creating an artificial fistula between the common carotid artery (CCA) and the external jugular vein (EJV) has been widely described and proved technically feasible. This construct provokes a consistent cerebral venous hypertension (CVH), and therefore has helped studying the contribution of venous hypertension to formation, clinical symptoms, and prognosis of brain AVMs and dural AVFs. Equivalent mice models have been only scarcely described and have shown trouble with stenosis of the fistula. An established murine model would allow the study of not only pathophysiology but also potential genetic therapies for these cerebrovascular diseases.
We present a model of arteriovenous fistula that produces a durable intracranial venous hypertension in the mouse. Microsurgical anastomosis of the murine CCA and EJV can be difficult due to diminutive anatomy and frequently result in a non-patent fistula. In this step-by-step protocol we address all the important challenges encountered during this procedure. Avoiding excessive retraction of the vein during the exposure, using 11-0 sutures instead of 10-0, and making a carefully planned end-to-side anastomosis are some of the critical steps. Although this method requires advanced microsurgical skills and a longer learning curve that the equivalent in the rat, it can be consistently developed.
This novel model has been designed to integrate transgenic mouse techniques with a previously well-established experimental system that has proved useful to study brain AVMs and dural AVFs. By opening the possibility of using transgenic mice, a broader spectrum of valid models can be achieved and genetic treatments can also be tested. The experimental construct could also be further adapted to the study of other cerebrovascular diseases related with venous hypertension such as migraine, transient global amnesia, transient monocular blindness, etc.

We describe a method for creating a reliable model of cerebral venous hypertension in the adult mouse. This model has been widely described and tested in the rat. This new counterpart in the mice opens the possibility of using genetic modified animals and thereby broadens the applications of the model.

成年小鼠静脉高压型号:颈总动脉，以颈外静脉吻合。

The understanding of the pathophysiology of brain arteriovenous malformations and arteriovenous fistulas has improved thanks to animal models. A rat model ...

Vascular Balloon Injury and Intraluminal Administration in Rat Carotid Artery

The carotid artery balloon injury model in rats has been well established for over two decades. It remains an important method to study the molecular and cellular mechanisms involved in vascular smooth muscle dedifferentiation, neointima formation and vascular remodeling. Male Sprague-Dawley rats are the most frequently employed animals for this model. Female rats are not preferred as female hormones are protective against vascular diseases and thus introduce a variation into this procedure. The left carotid is typically injured with the right carotid serving as a negative control. Left carotid injury is caused by the inflated balloon that denudes the endothelium and distends the vessel wall. Following injury, potential therapeutic strategies such as the use of pharmacological compounds and either gene or shRNA transfer can be evaluated. Typically for gene or shRNA transfer, the injured section of the vessel lumen is locally transduced for 30 min with viral particles encoding either a protein or shRNA for delivery and expression in the injured vessel wall. Neointimal thickening representing proliferative vascular smooth muscle cells usually peaks at 2 weeks after injury. Vessels are mostly harvested at this time point for cellular and molecular analysis of cell signaling pathways as well as gene and protein expression. Vessels can also be harvested at earlier time points to determine the onset of expression and/or activation of a specific protein or pathway, depending on the experimental aims intended. Vessels can be characterized and evaluated using histological staining, immunohistochemistry, protein/mRNA assays, and activity assays. The intact right carotid artery from the same animal is an ideal internal control. Injury-induced changes in molecular and cellular parameters can be evaluated by comparing the injured artery to the internal right control artery. Likewise, therapeutic modalities can be evaluated by comparing the injured and treated artery to the control injured only artery.

This protocol uses a balloon catheter to cause an intraluminal injury on the rat carotid artery and henceforth elicit neointimal hyperplasia. This is a well-established model for studying the mechanisms of vascular remodeling in response to injury. It is also widely used to determine the validity of potential therapeutic approaches.

血管球囊损伤和腔内管理在大鼠颈动脉

The carotid artery balloon injury model in rats has been well established for over two decades. It remains an important method to study the molecular and ...

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 ...

Cardiac Magnetic Resonance Imaging at 7 Tesla

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher magnetic field strengths and potentially provides improved signal contrast and spatial resolution. While promising results have been achieved, ultra-high field CMR is challenging due to energy deposition constraints and physical phenomena such as transmission field non-uniformities and magnetic field inhomogeneities. In addition, the magneto-hydrodynamic effect renders the synchronization of the data acquisition with the cardiac motion difficult. The challenges are currently addressed by explorations into novel magnetic resonance technology. If all impediments can be overcome, ultra-high field CMR may generate new opportunities for functional CMR, myocardial tissue characterization, microstructure imaging or metabolic imaging. Recognizing this potential, we show that multi-channel radio frequency (RF) coil technology tailored for CMR at 7 Tesla together with higher order B0 shimming and a backup signal for cardiac triggering facilitates high fidelity functional CMR. With the proposed setup, cardiac chamber quantification can be accomplished in examination times similar to those achieved at lower field strengths. To share this experience and to support the dissemination of this expertise, this work describes our setup and protocol tailored for functional CMR at 7 Tesla.

The sensitivity gain inherent to ultrahigh field magnetic resonance holds promise for high spatial resolution imaging of the heart. Here, we describe a protocol customized for functional cardiovascular magnetic resonance (CMR) at 7 Tesla using an advanced multi-channel radio-frequency coil, magnetic field shimming and a triggering concept.

7号特斯拉的心脏磁共振成像

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher ...

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

The goal of this method is to introduce a transgene into the endothelium of isolated segments of both rabbit common carotid arteries. The method achieves focal endothelial-selective transgenesis, thereby allowing an investigator to determine the biological roles of endothelial-expressed transgenes and to quantify the in vivo transcriptional activity of DNA sequences in large artery endothelial cells. The method uses surgical isolation of rabbit common carotid arteries and an arteriotomy to deliver a transgene-expressing viral vector into the arterial lumen. A short incubation period of the vector in the lumen, with subsequent aspiration of the lumen contents, is sufficient to achieve efficient and durable expression of the transgene in the endothelium, with no detectable transduction or expression outside of the isolated arterial segment. The method allows assessment of the biological activities of transgene products both in normal arteries and in models of human vascular disease, while avoiding systemic effects that could be caused either by targeting gene delivery to other sites (e.g. the liver) or by the alternative approach of delivering genetic constructs to the endothelium by germ line transgenesis. Application of the method is limited by the need for a skilled surgeon and anesthetist, a well-equipped operating room, the costs of purchasing and housing rabbits, and the need for expertise in gene-transfer vector construction and use. Results obtained with this method include: transgene-related alterations in arterial structure, cellularity, extracellular matrix, or vasomotor function; increases or reductions in arterial inflammation; alterations in vascular cell apoptosis; and progression, retardation, or regression of diseases such as intimal hyperplasia or atherosclerosis. The method also allows measurement of the ability of native and synthetic DNA regulatory sequences to alter transgene expression in endothelial cells, providing results that include: levels of transgene mRNA, levels of transgene protein, and levels of transgene enzymatic activity.