This work was partly supported by grants from the National Institutes of Health (NIH), under grant numbers R01 MH084021, R01 NS067015, R01 AG042753, NS076588, NS029029-20S1, R21 NS078656; and from National Multiple Sclerosis Society, under grant number of RG4707A2.

注：该协议被批准由得克萨斯大学西南医学中心的伦理审查委员会的大学。 图1.实验前的气体输送系统和准备的步骤<ol style="margin-left: 40px;"><li>审查的气体输送系统（ 图1）的图。填一个200升道格拉斯袋（项目＃1）用含有5％的CO 2，21％O 2，和74％的N 2的医用级的气体混合物。 </li><li>放置两个隔膜（项目＃4），在双向的非再呼吸阀（项目＃3），以确保单向气流。把这个组装双向阀和气体填充的道格拉斯袋（项目＃1）到磁体室。 </li><li>气体输送管（项目＃7）连接到双向阀（项目＃3）的输入端。附气体输送管（项目＃7）的头部线圈的侧配重支承。燃气输送管（编号7）的另一端连接到气体填充道格拉斯包（编号1）。 </li><li>连接喉舌（编号5）通过弯头连接的U形管（编号12）（编号13气体采样口密封）。 </li><li>连接气体取样管（编号：9）到U形管（编号12）通过其他弯头连接器（编号13）。 </li><li>连接一个小型空气过滤器（编号11）气体采样管（编号：9）的另一端。连接空气过滤器（编号：11）到CO 2（编号14）的另一端监控。 </li><li>在MRI套件的控制室，打开CO 2（编号14）和脉搏血氧饱和度（编号15）显示器。为CO 2的显示器进行自动校准。 </li><li>将显示器连接到使用USB接口的笔记本电脑。打开超级终端软件，与显示器进行通信。该显示器的次定时器写下定时器时间和相应的监视器的时间同步。的定时器时间和监视器的时间的差异将占到数据亲处理（对于步4.4）。 </li><li>插入信令杆的一端插入一个波导，使得棒的一端是所述磁铁的房间内，而另一端是在控制室。 注：信令栏用于三通阀的切换时，通知磁铁室内的研究者在扫描期间（项目＃2）是必要的。 </li></ol>在实验过程中2.程序<ol style="margin-left: 40px;"><li>让拍摄对象趴在桌子MRI但不要把他/她到磁铁孔呢。指示须按护士呼叫按钮，如果他们在扫描过程中感到不适。让拍摄对象擦拭他/她的鼻子用一块清洁湿巾，以消除任何油脂。 </li><li>指示需经口呼吸，并建立和维护一个呼吸节奏。然后应用鼻夹（编号6）关于这个问题。 </li><li>在U形管（编号12）的开口端连接的双向阀（编号3）通过EL中间口弓连接器（编号13）。 </li><li>轻轻将喉舌入主题的嘴里，这样的题目可以通过喉舌呼吸。轻轻附加的脉搏血氧饱和度（项目＃15）向受试者的指尖的手指传感器。 </li><li>确保被检体的头部是在头部线圈的异中心。操作MRI表将他磁铁孔内/她。 </li><li>确保一位研究人员住宿磁铁室内监控对象，并准备在道格拉斯袋（编号1）切换的三通阀。确保研究员戴耳塞和耳机，以阻止MRI噪音。 </li><li>关闭磁铁房间门，中控室，检查ETCO 2和动脉血氧饱和度分数（SO 2）对CO 2（编号14）和脉搏血氧饱和度（编号15）显示器显示的参数。开始在笔记本电脑上的参数的记录。 </li><li>指示MRI操作使用开始扫描血液氧合水平依赖（BOLD）序列。为3T MRI扫描器中，BOLD成像参数是：TR / TE = 1500/30毫秒，翻转角= 60°，视场= 220 X220毫米2，矩阵= 64×64，29片，厚度= 5毫米，片，361卷之间没有间隙。回顾在其上阀切换的定时列出一个预先准备片和当需要一个开关轻轻摆动的信令栏。狠抓主体的生理，包括心脏率，SO 2和ETCO 2。 </li><li>现在，在磁铁室内，关于道格拉斯袋切换基于所述信令杆，其控制气体受试者激发的类型的运动（项目＃1）。 </li><li>继续此过程为研究的长度。在9分钟拍摄期间，确保阀切换发生大约每分钟一次。需要注意的是开关的定时不必是完全精确的，只要所述的EtCO2时间过程被记录下来。&lt;BR /&gt;注：如果主体在扫描过程中按下护士呼叫按钮，扫描将中止与主体将立即搬出磁铁孔。研究者将移除口件和鼻夹从受试者。 </li><li>使用对讲机以通知扫描完成的课题。拉MRI表出来。从主题，同时提供清洁纸巾的主题擦拭任何口水轻轻取下鼻夹和喉舌。轻轻地取出从主题的脉搏血氧饱和度的手指传感器。那么这个问题可以坐起来，下车MRI表。 </li></ol>实验后3.清理程序<ol style="margin-left: 40px;"><li>丢弃气体采样管（编号9），空气过滤器（编号11），喉舌（项目5＃）和鼻夹（编号：6）。 </li><li>清洁可重用的组件。断开其他组件的双向阀（项目＃3）和（4项目＃）从阀移除隔膜。浸泡双向阀（项目＃3），隔膜（项目＃4）和U形管（项目＃12）中的浓缩无磷消毒剂，含有表面活性剂如在一容器中20分钟Bacdown洗涤剂消毒剂。洗涤剂消毒剂和蒸馏水的稀释比为1:64。 </li><li>冲洗在3.2用蒸馏水彻底描述的项​​目。 </li><li>干燥的U形管（编号12）用压缩空气。将二通阀（编号3）和隔膜（编号4）明确台面，让他们自然风干，彻底。 </li><li>清空道格拉斯袋。收起信令酒吧和灰色管。 </li></ol> 4.数据分析来计算CVR地图<ol style="margin-left: 40px;"><li>保存DICOM文件格式或任何其他供应商特定的格式MRI的数据。将数据传送到一个实验室计算机和数据转换成体积由卷文件系列，其中每个文件包含一个三维体积（ 例如，粗体图像）相对应的一个时间点。 </li><li>处理前的图像数据。执行图像的预处理步骤，包括重组，归一化，并使用该调用由软件统计参数映射（SPM）提供的库函数的脚本平滑。见补充代码文件1 Matlab的脚本的一个例子。 </li><li>使用脚本来读取的CO 2记录，通过由预先校准量移位的时间过程纠正采样管延迟（ 例如，12秒在此设置中被确定为一个呼吸之间的时间差来嘴件和外观上的CO 2记录该呼吸）的，并提取的EtCO2这是原始的时间序列的包络线（正峰）。见补充代码文件2 Matlab的脚本。 </li><li>基于该同步定时器，该段ETCO 2数据只保留记录从25秒的最后图像采集之后的第一个图像采集到100秒之前。在ETCO 2次课程输入功能的脉管，并用作在后述的线性回归分析的独立变量。 </li><li>通过计算这两个时间过程之间的交叉相关系数（CC）在不同的时间偏移确定ETCO 2（肺测量）和MRI信号（在大脑中测量）之间的生理时滞。能产生较高的CC移位值被认为是最佳时间。 </li><li>所述ETCO 2时间过程是由最佳延迟移位并且只有时间点匹配那些磁共振信号被保留，导致在一个时间序列是相同长度的磁共振信号。 </li><li>进行使用的SPM体素逐体素的线性回归，其中错开的EtCO2时间过程是自变量和核磁共振信号的时间过程是因变量。 </li><li>计算体素逐体素CVR的地图 <img alt="式（1）" fo:content-width="2in" src="/files/ftp_upload/52306/52306eq1.jpg" /> 其中，（I，J，K）是叔他体素索引，β1是与的EtCO2和β0相关的回归系数与常数项相关的回归系数。 分钟（ETCO 2）ETCO 2中的时间过程的最小值。 </li></ol>

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HL and PL are inventors of a provisional patent, owned by UT Southwestern Medical Center, that describes part of the gas delivery system.

本报告中提出的MR兼容的气体输送系统和一个综合实验协议，允许血管反应性的人脑的映射。气体输送系统的示意图示于图1。MRI扫描仪的房间内所有零件都是塑料，以确保他们的MRI兼容性。该系统可在概念上划分为三个子系统，包括一个进气子系统（袋，输送管，双向阀），一个呼吸接口子系统（鼻夹，嘴件，U形管），和监测子系统（CO 2浓度，氧饱和度，心脏速率，呼吸速率）。气进气子系统允许气体被吸入到达阀双向。仅吸入空气，但不能呼出的空气，将流过此子系统。呼吸接口子系统允许受呼吸进出预定气体。无论吸入和呼出的气体会流过该子系统。该monitorin因此克子系统应采样气体在沿着呼吸接口子系统的一个点。 这种技术的临床应用可以包括在神经系统的疾病，如中风，动脉粥样硬化，烟雾病，血管性痴呆，多发性硬化症，脑肿瘤脑血管储备的评价。该技术也可用于在功能性磁共振成像研究，以正常化或校准的fMRI信号为更好地量化神经活动23,24。 所提出的系统和实验方案的一个重要特征是，该气体混合物可被递送给受试者同时引起最少的运动或不适。因此，关键是要放置在U形管（项目＃12），使得它（以及连接到它的端部的吹口）自然落入向下进入被检者的口腔。这样一来，这个问题并不需要使用自己的面部肌肉以保持或支持的喉舌。它也是进口蚂蚁要知道，这个问题将无法说话，而喉舌，是在口里。因此，研究人员应该避免谈论同一个问题基调的主题。相反，只有清晰的，明确的说明，应该放在首位。此外，研究人员应该在实验的整个过程中密切关注生理参数（ 例如，ETCO 2，SO 2，心脏率，呼吸率），当一个或多个生理参数的偏差之外的典型范围及时回复。 而其他气体输送系统的详尽调查，在文献中使用已经超出了本文的范围，它在当前的系统比较了几个常用的17,18是有用的。一个主要的不同之处在于我们的系统使用一个吹口，提供预定的气体，而大多数其他系统已经使用在设计的掩模。使用掩模的潜在并发症是2倍。首先，口罩Øccupies的空间相当量，并且它可能不总是可行的，以适应所述掩模到头部线圈内的狭小空间，考虑的是，对于许多受试者，他们的鼻子几乎触碰磁头线圈，即使没有掩模。这是特别适用于旨在实现高灵敏度磁头线圈，其通常被设计以牢固地镶嵌到被检者的头部的情况。用的掩模设计相关联的第二个复杂的是，有导致吸入和呼出气体的实质性混合掩模内部大的空间。因此，它可能会影响ETCO 2，其中理想地，应仅基于呼出气体测定的准确性。准确ETCO 2当然是对CVR地图的可靠性很重要的。我们的系统相比，许多其它的系统的另一个主要区别是，我们的系统从一个袋，而不是一个气体罐提供燃气。因此，不需要在扫描仪领域的坦克，节省了宝贵的空间，在续<html> ROL房间的MRI套房。在我们的设计中，我们把包包扫描开始前，扫描之后，袋子被清空，折叠放好。最后，相比其它几个系统18,21，电流气体输送系统是简单，需要更少的训练时间，并且它的消耗品成本更低。 应当指出的是，虽然在本报告中提出的协议主要集中在CO 2的吸入，所提出的气体输送系统允许其它气体混合物（交付如任何分数的 O 2，CO 2的任何部分，任何的N 2，和它们的组合）分数，以人类为他们而他/她是躺在核磁共振成像扫描仪内呼吸。一还可以使用气体输送系统的MRI的上下文之外，例如结合脑电图（EEG），脑磁图（MEG），正电子发射断层扫描（PET），或最佳成像。 _content“&gt;当提供的摄像参数的建议，我们已主要集中在BOLD序列。可在CVR映射来潜在地使用的另一种序列是动脉自旋标记（ASL）的磁共振成像，它提供了脑血流量的定量测量（CBF）在生理单位（毫升每分钟100克组织血），因此，ASL基CVR映射的优点是，其结果是容易解释，不像BOLD信号反映血流量，血液量的组合效果，以及脑代谢改变的过程中的CO 2的挑战25-27可能作出的贡献，但是，在ASL技术的一个限制是，它的灵敏度比BOLD 28的下部数倍。其结果是，我们的经验是，目前，它是极具挑战性，以获得个人层面，素逐体素使用ASL。因此，对于CVR的应用研究中，我们主要使用了BOLD序列CVR的地图，因此也集中在这一技术中的OUR建议。 本方法的一个限制是，通过与鼻堵塞（由一鼻夹）吹嘴的呼吸是不完全的自然和一些受试者（尤其是人）可能会认为这是不舒服的来源。与吹嘴和鼻夹呼吸也可能加剧幽闭恐惧的感觉。此外，主题可能会遇到口干，由于只张口呼吸。因此，建议研究人员极力向完成实验迅速。最后，要注意的是，根据作者的经验，上述潜在的不适是短暂的，将尽快在实验结束后消失是很重要的。

大脑表示约2％的总体重，但消耗约20％的总能量1。不足为奇的是，足够的，并仔细调节的血液供应是至关重要满足这种高能量需求，并且为大脑才能正常工作。此外，大脑是一个空间异构和时间上的动态器官，具有不同区域需要不同量的血液供应的不同时间。因此，动态血液供应的调制代表在人脑循环的重要要求。幸运的是，这是已知的血管不只是刚性管和血管的一个重要功能是扩张并基于大脑和需求生理条件2收缩。 容器中，被称为脑血管-反应器（CVR）的此功能特性，被认为是血管健康的有用指示器，并且可以发现在几个神经conditio应用纳秒如中风3，痴呆4，动脉粥样硬化5，小血管疾病6，脑瘤7，烟雾病8，和药物成瘾9。在生理学和麻醉文献，已知的是，因为二氧化碳气体是一种强效血管扩张剂，CVR可以评估通过改变动脉的 CO 2水平（ 例如，吸入少量的CO 2），同时监测血管反应10-13 。在成像和放射领域，利用MRI CVR映射正在迅速成为了许多基本的科学家和临床医生8,14-19利益的新标志。它通常是通过检查多血管反应是如何引起的一个挑战血管活性估计。然而，有必要在气体输送系统的技术进步和实验方案的标准化。提供特殊的气体混合物的MRI扫描仪内部主体是不平凡的，并特别注意事项都需要一个MRI兼容的设计。特别注意事项，需要在设计MRI兼容的气体输送系统。这些特殊的考虑因素包括：1）中的所有组件必须是非金属（金属不能里面的MRI使用）; 2）系统应该工作在一个小空间，该MRI系统和它的头部线圈允许; 3）系统应以卧向下的位置工作（如MRI扫描仪需要），而不是坐起来，没有不适; 4）相关的生理参数，如潮气末CO 2（的EtCO2，在动脉血二氧化碳含量）和动脉血氧饱和度的近似，应准确记录的定时精度秒并存储在计算机用于分析用途上。这些问题可能​​会限制CVR映射的应用范围。 在这份报告中，我们提出了一个使用全面的气体输送系统，以调节启发气体的内容，而主题是躺在核磁共振成像扫描仪内的实验方案。我们荷兰国际集团这种方法，研究人员可以非侵入性地应用一个血管活性刺激物以最小的不适或整体运动的参与者。在约9分钟的整个时期，其中包括了室内空气和高二氧化碳气体呼吸交替块（每块1分钟），记录生理参数和MRI影像。代表性的结果。潜在的应用和局限性进行了讨论。

<table border="0" cellpadding="0" cellspacing="0" width="978">
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			<td height="61" style="height:61px;width:211px;">Name of the Material/Equipment</td>
			<td style="width:171px;">Company</td>
			<td style="width:109px;">Catalog number</td>
			<td style="width:179px;">Description</td>
			<td style="width:311px;">Website</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Douglas bag&#160;</td>
			<td>Harvard Apparatus</td>
			<td>500942</td>
			<td>200-liter capacity</td>
			<td>http://www.harvardapparatus.com/webapp/wcs/stores/servlet/catalog_11051_10001_-1_HAI?gclid=CN_woMnCwboCFWpk7AodL1YA8g</td>
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		<tr height="34">
			<td height="34" style="height:34px;">Three-way valve</td>
			<td>Hans Rudolph</td>
			<td>CR1207</td>
			<td>100% plastic</td>
			<td>www.rudolphkc.com&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Two-way non-rebreathing valve</td>
			<td>Hans Rudolph</td>
			<td>CR1480</td>
			<td>22mm/ 15mm ID</td>
			<td>www.rudolphkc.com&#160;</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;">Diaphragm</td>
			<td>Hans Rudolph</td>
			<td>602021-2608</td>
			<td>Size: medium, Type: spiral</td>
			<td>www.rudolphkc.com&#160;</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;">Mouth piece</td>
			<td>Hans Rudolph</td>
			<td>602076</td>
			<td>Silicone, Model #&#160;9061</td>
			<td>www.rudolphkc.com&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Nose clip</td>
			<td>Hans Rudolph</td>
			<td>201413</td>
			<td>Plastic foam, Model #9014</td>
			<td>www.rudolphkc.com&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Gas delivery tube</td>
			<td>Vacumed</td>
			<td>1011-108</td>
			<td></td>
			<td>http://www.vacumed.com/zcom/product/Product.do?compid=27&#38;prodid=7665</td>
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		<tr height="20">
			<td height="20" style="height:20px;">Blue cuff</td>
			<td>Vacumed</td>
			<td>22254</td>
			<td></td>
			<td>http://www.vacumed.com/zcom/product/Product.do?compid=27&#38;prodid=343</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Gas sampling tube</td>
			<td>QoSINA</td>
			<td>T4305</td>
			<td>Thin</td>
			<td>http://www.qosina.com/catalog/part.asp?partno=T4305</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Male luer</td>
			<td>QoSINA</td>
			<td>11547</td>
			<td></td>
			<td>http://www.qosina.com/catalog/part.asp?partno=11547</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Hydrophobic filter</td>
			<td>Philips Medical Systems</td>
			<td>9906-00</td>
			<td>Disposable</td>
			<td>http://www.healthcare.philips.com/us_en/products/index.wpd?Int_origin=3_HC_landing_main_us_en_top-nav_products</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">U-shape tube</td>
			<td>Made in-house</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Elbow connector</td>
			<td>QoSINA</td>
			<td>51033</td>
			<td></td>
			<td>www.qosina.com</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">EtCO2monitor</td>
			<td>Philips Medical Systems</td>
			<td>Model 1265</td>
			<td></td>
			<td>http://www.healthcare.philips.com/us_en/products/index.wpd?Int_origin=3_HC_landing_main_us_en_top-nav_products</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Pulse oximetry&#160;</td>
			<td>Invivo</td>
			<td>Expression</td>
			<td>MRI Monitoring Systems</td>
			<td>http://www.invivocorp.com/monitors/monitorinfo.php?id=7</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">MRI scanner&#160;</td>
			<td>Philips</td>
			<td>Achieva 3.0T TX</td>
			<td></td>
			<td>http://www.healthcare.philips.com/main/products/mri/systems/achievaTX/?Int_origin=2_HC_mri_main_global_en_systems_achieva30ttx</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Disinfectant</td>
			<td>Fisher Scientific</td>
			<td>04-355-13</td>
			<td style="width:179px;">Decon&#8482; BDD&#8482; Bacdown&#8482; Detergent Disinfectant</td>
			<td>http://www.fishersci.com/ecomm/servlet/itemdetail?storeId=10652&#38;langId=-1&#38;catalogId=29104&#38;productId=3426739&#38;distype=0&#38;highlightProductsItemsFlag=Y&#38;fromSearch=1&#38;searchType=PROD&#38;hasPromo=0</td>
		</tr>
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</table>

mri mapping of cerebrovascular reactivity via gas inhalation challenges

大脑是一个异类空间和时间上的动态的器官，不同的地区需要不同量的血液供应，在不同的时间。因此，对血管扩张或收缩的能力，被称为脑血管-反应器（CVR），表示血管功能的一个重要领域。成像标记物表示此动态属性将提供正常和病变情况，如中风，痴呆，动脉粥样硬化，小血管疾病，脑肿瘤，脑外伤，多发性硬化下脑血管的新的信息。为了在人类中执行这种类型的测量中，有必要提供一个血管活性刺激物如CO 2和/或O 2的气体混合物的同时定量脑磁共振图像（MRI）被收集。在这项工作中，我们提出了一个MR兼容的气体输送系统和相关的协议，该协议允许的特殊气体混合物的输送（ 例如， </EM&gt; 的 O 2，CO 2，N 2，以及它们的组合），而受试者躺在MRI扫描仪的内部。该系统是相对简单的，经济的，并易于使用，并且在实验协议允许CVR在两个健康志愿者和患有神经障碍精确测绘的。这种方法具有在广泛的临床应用和更好地理解脑血管的病理生理学中使用的潜力。在视频中，我们演示了如何建立系统的MRI套件内，如何在人类参与者执行一个完整的实验。

两种类型的数据收集与所提出的协议，生理录音和MR图像; 图生理参数2和3显示从记录有代表性的受试者。 如图黑色迹2显示的 CO 2时程记录通过CO 2的显示器，其表示在空气采样附近的吹嘴的CO 2的含量。请注意，此跟踪快速波动与时间的函数。这是因为，在呼吸循环的吸入阶段，该记录反映了吸入空气中的CO 2的含量，并在呼气阶段，这种记录反映在呼出的空气中的 CO 2含量。这样，每个呼吸周期的上限峰值，被称为潮气末CO 2或ETCO 2，表示在肺，其可近似用作CO 2浓度在动脉血中的 CO 2含量。注日在CO 2浓度的动脉血是驱动力， 即输入功能，血管扩张反应。 CO 2的迹线（红色曲线于图2）的峰值分别划定一个检测算法，其中每个呼吸期间搜索峰值，与人工检验和校正的组合。其次的中值滤波，以除去由于部分呼吸突然峰和从肺血管脑血管的流动的过程中，考虑到血液混合。最后ETCO 2时间过程示出由绿色曲线在图2中，它是用来在CVR的计算。 图3示出了呼吸率，动脉血氧饱和度分数（SO 2），和心脏速率的时间进程。呼吸率从CO 2的显示器，同时获得SO 2和心脏率从脉搏血氧饱和度获得。由于可以为sEEN，这些参数不显示的高碳酸血症的挑战系统性的变化。注意，高碳酸血症不会引起过度通气中的主体，从而在肺中的O 2的分压会增加适度。然而，其对SO 2的影响是微乎其微的血红蛋白已经基本饱和，在室内空气呼吸和氧解离曲线是该范围内的相当平坦。 图4显示了在不同的实验时间代表BOLD MR图像。平均信号强度（任意MR单位）也被示出。由此可以看出，在大脑中的BOLD信号显示增加用CO 2吸入。需要注意的是房间空气和CO 2周期之间的信号差为1-3％的幅度的量级。 组合来自生理录音和MR图像数据，体素逐体素CVR地图可以计算。 图5示出了代表CVR图（以每毫米汞柱的CO 2的变化％的信号变化的单位）上扫描五个不同天健康受试者，展示结果的极好的再现性。所提出的技术迄今已在老化20，阿尔茨海默氏病4，多发性硬化症21，和运动训练22的研究中得到了应用。 <img alt="图1" src="/files/ftp_upload/52306/52306fig1highres.jpg" /> 图1.气体输送系统的示意图。 <a href="https://www.jove.com/files/ftp_upload/52306/52306fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/52306/52306fig2highres.jpg" /> 图2. CO 2的时间从代表主体杜课程响的实验。呼吸-呼吸的CO 2含量迹所记录的CO 2的显示器示出为室内空气呼吸周期（左下）和5％的CO 2的吸入期间（右下）段。提取ETCO 2时的课程都显示在彩色曲线。 <a href="https://www.jove.com/files/ftp_upload/52306/52306fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/52306/52306fig3highres.jpg" /> 图3.记录生理参数从在实验过程中有代表性的问题。（A）的呼吸率（BPM，每分钟呼吸）的主题的时间过程。（B）中 ，以便被检体2（％）时间过程。（C）的心脏率（BPM，每分钟节拍）的主题时程。主题是<html>同样的一个作为在图1。 <a href="https://www.jove.com/files/ftp_upload/52306/52306fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/52306/52306fig4highres.jpg" /> 图在不同的实验时间4。代表BOLD MR图像。显示的脑片的平均信号强度（以MNI空间轴向层面＃54）显示在最 ​​后一行。 <a href="https://www.jove.com/files/ftp_upload/52306/52306fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" src="/files/ftp_upload/52306/52306fig5highres.jpg" /> 图由代表主体代表性的CVR地图。.jove.com /文件/ ftp_upload / 52306 / 52306fig5large.jpg“目标=”_空白“&gt;点击此处查看该图的放大版本。

Watch this Scientific Journal Video about MRI Mapping of Cerebrovascular Reactivity via Gas Inhalation Challenges at JoVE.com

MRI Mapping of Cerebrovascular Reactivity via Gas Inhalation Challenges

Non-invasive imaging of the brain vasculature&#8217;s ability to dilate or constrict may allow a better understanding of cerebrovascular pathophysiology in various neurological diseases. The present report describes a reproducible and patient-comfortable protocol to perform vascular reactivity imaging in humans using magnetic resonance imaging (MRI).

脑血管反应性通过气体吸入挑战MRI映射

The brain is a spatially heterogeneous and temporally dynamic organ, with different regions requiring different amount of blood supply at different time. ...

mri-mapping-cerebrovascular-reactivity-via-gas-inhalation

Research

JoVE Journal

Medicine

13.8K 次观看.  University of Texas Southwestern Medical Center. Non-invasive imaging of the brain vasculature’s ability to dilate or constrict may allow a better understanding of cerebrovascular pathophysiology in various neurological diseases. The present report describes a reproducible and patient-comfortable protocol to perform vascular reactivity imaging in humans using magnetic resonance imaging (MRI).

视频: MRI Mapping of Cerebrovascular Reactivity via Gas Inhalation Challenges

Microsurgical Venous Pouch Arterial-Bifurcation Aneurysms in the Rabbit Model: Technical Aspects

For ruptured human cerebral aneurysms endovascular embolization has become an equivalent alternative to aneurysm clipping.1 However, large clinical trials have shown disappointing long-term results with unacceptable high rates of aneurysm recanalization and delayed aneurysm rupture.2 To overcome these problems, animal experimental studies are crucial for the development of better endovascular devices.3-5
Several animal models in rats, rabbits, canines and swine are available.6-8 Comparisons of the different animal models showed the superiority of the rabbit model with regard to hemodynamics and comparability of the coagulation system and cost-effectiveness.9-11 
The venous pouch arterial bifurcation model in rabbits is formed by a venous pouch sutured into an artificially created true bifurcation of both common carotid arteries (CCA). The main advantage of this model are true bifurcational hemodynamics.12 The major drawbacks are the sofar high microsurgical technical demands and high morbidity and mortality rates of up to 50%.13 These limitations have resulted in less frequent use of this aneurysm model in the recent years. These shortcomings could be overcome with improved surgical procedures and modified peri- and postoperative analgetic management and anticoagulation.14-16 Our techniques reported in this paper demonstrate this optimized technique for microsurgical creation of arterial bifurcation aneurysms.

An optimized technique for the microsurgical creation of arterial bifurcation aneurysms mimicking bifurcation human cerebral aneurysms is described. A venous pouch is sutured into an artificially created true bifurcation of both common carotid arteries. Facilitated microsurgical techniques and aggressive postoperative anticoagulation and analgesia lead to minimized morbidity rates and high aneurysm patency rates.

显微静脉袋分岔动脉瘤在兔模型：技术问题

For ruptured human cerebral aneurysms endovascular embolization has become an equivalent alternative to aneurysm clipping.1 However, large clinical trials ...

科研

医学

Visualization and Analysis of Blood Flow and Oxygen Consumption in Hepatic Microcirculation: Application to an Acute Hepatitis Model

There is a considerable discrepancy between oxygen supply and demand in the liver because hepatic oxygen consumption is relatively high but about 70% of the hepatic blood supply is poorly oxygenated portal vein blood derived from the gastrointestinal tract and spleen. Oxygen is delivered to hepatocytes by blood flowing from a terminal branch of the portal vein to a central venule via sinusoids, and this makes an oxygen gradient in hepatic lobules. The oxygen gradient is an important physical parameter that involves the expression of enzymes upstream and downstream in hepatic microcirculation, but the lack of techniques for measuring oxygen consumption in the hepatic microcirculation has delayed the elucidation of mechanisms relating to oxygen metabolism in liver. We therefore used FITC-labeled erythrocytes to visualize the hepatic microcirculation and used laser-assisted phosphorimetry to measure the partial pressure of oxygen in the microvessels there. Noncontact and continuous optical measurement can quantify blood flow velocities, vessel diameters, and oxygen gradients related to oxygen consumption in the liver. In an acute hepatitis model we made by administering acetaminophen to mice we observed increased oxygen pressure in both portal and central venules but a decreased oxygen gradient in the sinusoids, indicating that hepatocyte necrosis in the pericentral zone could shift the oxygen pressure up and affect enzyme expression in the periportal zone. In conclusion, our optical methods for measuring hepatic hemodynamics and oxygen consumption can reveal mechanisms related to hepatic disease.

An optical system was developed to visualize hepatic microcirculation with FITC-labeled erythrocytes and to measure the partial pressure of oxygen in the microvessels with laser-assisted phosphorimetry. This method can be used to investigate physiological and pathological mechanisms by analyzing microvascular structure, diameter, blood flow velocity, and oxygen tension.

可视化和肝脏微循环血流量和耗氧量分析：急性肝炎模型中的应用

There is a considerable discrepancy between oxygen supply and demand in the liver because hepatic oxygen consumption is relatively high but about 70% of ...

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 ...

Coordinate Mapping of Hyolaryngeal Mechanics in Swallowing

Characterizing hyolaryngeal movement is important to dysphagia research. Prior methods require multiple measurements to obtain one kinematic measurement whereas coordinate mapping of hyolaryngeal mechanics using Modified Barium Swallow (MBS) uses one set of coordinates to calculate multiple variables of interest. For demonstration purposes, ten kinematic measurements were generated from one set of coordinates to determine differences in swallowing two different bolus types. Calculations of hyoid excursion against the vertebrae and mandible are correlated to determine the importance of axes of reference.
To demonstrate coordinate mapping methodology, 40 MBS studies were randomly selected from a dataset of healthy normal subjects with no known swallowing impairment. A 5 ml thin-liquid bolus and a 5 ml pudding swallows were measured from each subject. Nine coordinates, mapping the cranial base, mandible, vertebrae and elements of the hyolaryngeal complex, were recorded at the frames of minimum and maximum hyolaryngeal excursion. Coordinates were mathematically converted into ten variables of hyolaryngeal mechanics.
Inter-rater reliability was evaluated by Intraclass correlation coefficients (ICC). Two-tailed t-tests were used to evaluate differences in kinematics by bolus viscosity. Hyoid excursion measurements against different axes of reference were correlated. Inter-rater reliability among six raters for the 18 coordinates ranged from ICC = 0.90 - 0.97. A slate of ten kinematic measurements was compared by subject between the six raters. One outlier was rejected, and the mean of the remaining reliability scores was ICC = 0.91, 0.84 - 0.96, 95% CI. Two-tailed t-tests with Bonferroni corrections comparing ten kinematic variables (5 ml thin-liquid vs. 5 ml pudding swallows) showed statistically significant differences in hyoid excursion, superior laryngeal movement, and pharyngeal shortening (p &#60; 0.005). Pearson correlations of hyoid excursion measurements from two different axes of reference were: r = 0.62, r2 = 0.38, (thin-liquid); r = 0.52, r2 = 0.27, (pudding).
Obtaining landmark coordinates is a reliable method to generate multiple kinematic variables from video fluoroscopic images useful in dysphagia research.

Coordinate mapping is a method of documenting salient features of hyolaryngeal biomechanics in the pharyngeal phase of swallowing. This methodology uses image analysis software to record coordinates of anatomical landmarks. These coordinates are imported into an excel macro and translated into kinematic variables of interest useful in dysphagia research.

协调Hyolaryngeal力学映射在吞咽

Characterizing hyolaryngeal movement is important to dysphagia research. Prior methods require multiple measurements to obtain one kinematic measurement ...

Preparation Steps for Measurement of Reactivity in Mouse Retinal Arterioles Ex Vivo

Vascular insufficiency and alterations in normal retinal perfusion are among the major factors for the pathogenesis of various sight-threatening ocular diseases, such as diabetic retinopathy, hypertensive retinopathy, and possibly glaucoma. Therefore, retinal microvascular preparations are pivotal tools for physiological and pharmacological studies to delineate the underlying pathophysiological mechanisms and to design therapies for the diseases. Despite the wide use of mouse models in ophthalmic research, studies on retinal vascular reactivity are scarce in this species. A major reason for this discrepancy is the challenging isolation procedures owing to the small size of these retinal blood vessels, which is ~ &#8804; 30 &#181;m in luminal diameter. To circumvent the problem of direct isolation of these retinal microvessels for functional studies, we established an isolation and preparation technique that enables ex vivo studies of mouse retinal vasoactivity under near-physiological conditions. Although the present experimental preparations will specifically refer to the mouse retinal arterioles, this methodology can readily be employed to microvessels from rats.

Preparation Steps for Measurement of Reactivity in Mouse Retinal Arterioles Ex Vivo

Many vision-threatening ocular diseases are associated with dysfunctional retinal microvessels. Therefore, the measurement of retinal arteriole responses is important to investigate the underlying pathophysiological mechanisms. This article describes a detailed protocol for mouse retinal arteriole isolation and preparation to assess the effects of vasoactive substances on vascular diameter.

小鼠视网膜微动脉的反应性测定的制备步骤前体

Vascular insufficiency and alterations in normal retinal perfusion are among the major factors for the pathogenesis of various sight-threatening ocular ...

Novel Methods for Intranasal Administration Under Inhalation Anesthesia to Evaluate Nose-to-Brain Drug Delivery

Intranasal administration has been reported to be a potential pathway for nose-to-brain delivery of therapeutic agents that circumvents the blood-brain barrier. However, there have been few reports regarding not only the quantitative analysis but also optimal administration conditions and dosing regimens for investigations of nose-to-brain delivery. The limited progress in research on nose-to-brain pathway mechanisms using rodents represents a significant impediment in terms of designing nose-to-brain delivery systems for candidate drugs.
To gain some headway in this regard, we developed and evaluated two novel methods of stable intranasal administration under inhalation anesthesia for experimental animals. We also describe a method for the evaluation of drug distribution levels in the brain via the nose-to-brain pathway using radio-labeled [14C]-inulin (molecular weight: 5,000) as a model substrate of water-soluble macromolecules.
Initially, we developed a pipette-based intranasal administration protocol using temporarily openable masks, which enabled us to perform reliable administration to animals under stable anesthesia. Using this system, [14C]-inulin could be delivered to the brain with little experimental error.
We subsequently developed an intranasal administration protocol entailing reverse cannulation from the airway side through the esophagus, which was developed to minimize the effects of mucociliary clearance (MC). This technique led to significantly higher levels of [14C]-inulin, which was quantitatively detected in the olfactory bulb, cerebrum, and medulla oblongata, than the pipette method. This appears to be because retention of the drug solution in the nasal cavity was substantially increased by active administration using a syringe pump in a direction opposite to the MC into the nasal cavity.
In conclusion, the two methods of intranasal administration developed in this study can be expected to be extremely useful techniques for evaluating pharmacokinetics in rodents. The reverse cannulation method, in particular, could be useful for evaluating the full potential of nose-to-brain delivery of drug candidates.

Here, we describe two novel methods of stable intranasal administration under inhalation anesthesia with minimal physical stress for experimental animals. We also describe a method for quantitative evaluation of drug distribution levels in the brain via the nose-to-brain pathway using radiolabeled [14C]-inulin as a model substrate of water-soluble macromolecules.

吸入麻醉下鼻内给药评价鼻腔给脑药物的新方法

Intranasal administration has been reported to be a potential pathway for nose-to-brain delivery of therapeutic agents that circumvents the blood-brain ...

Use of MRI-ultrasound Fusion to Achieve Targeted Prostate Biopsy

Here, we present a protocol to perform targeted prostate biopsy using a magnetic resonance imaging-ultrasound (MRI/US) fusion system. Prostate cancer has traditionally been diagnosed via transrectal ultrasound (TRUS) biopsy. Though considered the gold standard, TRUS is unable to visualize most prostate cancer lesions and therefore requires sampling of the entire prostate. This biopsy method often undergrades prostate cancer and fails to detect up to 35% of cancers on initial biopsy. Prostate MRI has been shown to have excellent sensitivity in the detection of cancerous lesions, and advancements in MRI technology during the last decade have led to the development of targeted biopsy. In targeted biopsy, a software platform overlays MRI data onto live TRUS images to create a fused MRI/US three-dimensional model of the prostate. Regions suspicious for malignancy on MRI are contoured by a radiologist, uploaded into the fusion system, and then displayed within the live MRI/US fused model. The urologist is then able to directly biopsy these targets. When compared to conventional TRUS biopsy, MRI/US fusion technology has been demonstrated to improve the detection of clinically significant cancer while reducing insignificant cancer detection. This technology, therefore, has the potential to diagnose prostate cancer primarily in men who would benefit from treatment.

Presented herein is a protocol to perform targeted biopsy of the prostate using an MRI-ultrasound fusion system.

Mri-超声融合技术在靶向前列腺活检中的应用

Here, we present a protocol to perform targeted prostate biopsy using a magnetic resonance imaging-ultrasound (MRI/US) fusion system. Prostate cancer has ...

High-Throughput Analysis of Optical Mapping Data Using ElectroMap

Optical mapping is an established technique for high spatio-temporal resolution study of cardiac electrophysiology in multi-cellular preparations. Here we present, in a step-by-step guide, the use of ElectroMap for analysis, quantification, and mapping of high-resolution voltage and calcium datasets acquired by optical mapping. ElectroMap analysis options cover a wide variety of key electrophysiological parameters, and the graphical user interface allows straightforward modification of pre-processing and parameter definitions, making ElectroMap applicable to a wide range of experimental models. We show how built-in pacing frequency detection and signal segmentation allows high-throughput analysis of entire experimental recordings, acute responses, and single beat-to-beat variability. Additionally, ElectroMap incorporates automated multi-beat averaging to improve signal quality of noisy datasets, and here we demonstrate how this feature can help elucidate electrophysiological changes that might otherwise go undetected when using single beat analysis. Custom modules are included within the software for detailed investigation of conduction, single file analysis, and alternans, as demonstrated here. This software platform can be used to enable and accelerate the processing, analysis, and mapping of complex cardiac electrophysiology.

This protocol describes the setup and use of ElectroMap, a MATLAB-based open-source software platform for analysis of cardiac optical mapping data. ElectroMap provides a versatile high-throughput tool for analysis of optical mapping voltage and calcium datasets across a wide range of cardiac experimental models.

使用电子地图的光映射数据的高通量分析

Optical mapping is an established technique for high spatio-temporal resolution study of cardiac electrophysiology in multi-cellular preparations. Here we ...

A Novel Inhalation Mask System to Deliver High Concentrations of Nitric Oxide Gas in Spontaneously Breathing Subjects

Nitric Oxide (NO) is administered as gas for inhalation to induce selective pulmonary vasodilation. It is a safe therapy, with few potential risks even if administered at high concentration. Inhaled NO gas is routinely used to increase systemic oxygenation in different disease conditions. The administration of high concentrations of NO also exerts a virucidal effect in vitro. Owing to its favorable pharmacodynamic and safety profiles, the familiarity in its use by critical care providers, and the potential for a direct virucidal effect, NO is clinically used in patients with coronavirus disease-2019 (COVID-19). Nevertheless, no device is currently available to easily administer inhaled NO at concentrations higher than 80 parts per million (ppm) at various inspired oxygen fractions, without the need for dedicated, heavy, and costly equipment. The development of a reliable, safe, inexpensive, lightweight, and ventilator-free solution is crucial, particularly for the early treatment of non-intubated patients outside of the intensive care unit (ICU) and in a limited-resource scenario. To overcome such a barrier, a simple system for the non-invasive NO gas administration up to 250 ppm was developed using standard consumables and a scavenging chamber. The method has been proven safe and reliable in delivering a specified NO concentration while limiting nitrogen dioxide levels. This paper aims to provide clinicians and researchers with the necessary information on how to assemble or adapt such a system for research purposes or clinical use in COVID-19 or other diseases in which NO administration might be beneficial.

This simple and highly adaptable system device for the inhalation of high-concentration nitric oxide (NO) gas does not require mechanical ventilators, positive pressure, or high gas flows. Standard medical consumables and a snug-fitting mask are used to safely deliver NO gas to spontaneously breathing subjects.

一种新型吸入面膜系统，可在自发呼吸受试者中提供高浓度的一氧化氮气体

Nitric Oxide (NO) is administered as gas for inhalation to induce selective pulmonary vasodilation. It is a safe therapy, with few potential risks even if ...

Creation of Two Saccular Elastase-Digested Aneurysms with Different Hemodynamics in One Rabbit

Preclinical animal models with hemodynamic, morphologic, and histologic characteristics close to human intracranial aneurysms play a key role in the understanding of the pathophysiological processes and the development and testing of new therapeutic strategies. This study aims to describe a new rabbit aneurysm model that allows the creation of two elastase-digested saccular aneurysms with different hemodynamic conditions within the same animal.
Five female New Zealand white rabbits with a mean weight of 4.0 (&#177; 0.3) kg and mean age of 25 (&#177;5) weeks underwent microsurgical stump and bifurcation aneurysm creation. One aneurysm (stump) was created by right common carotid artery (CCA) exposure at its origin at the brachiocephalic trunk. A temporary clip was applied at the CCA origin and another, 2 cm above. This segment was treated with a local injection of 100 U of elastase for 20 min. A second aneurysm (bifurcation) was created by suturing an elastase-treated arterial pouch into the end-to-side anastomosis of the right CCA to left CCA. Patency was controlled by fluorescence angiography immediately after creation.
The average duration of surgery was 221 min. The creation of two aneurysms in the same animal was successful in all rabbits without complication. All aneurysms were patent immediately after surgery except for one bifurcation aneurysm, which showed an extreme tissue reaction due to elastase incubation and an immediate intraluminal thrombosis. No mortality was observed during surgery and up to one-month follow-up. Morbidity was limited to a transient vestibular syndrome (one rabbit), which recovered spontaneously within one day.
Demonstrated here for the first time is the feasibility of creating a two-aneurysm rabbit model with stump and bifurcation hemodynamic characteristics and highly degenerated wall conditions. This model allows the study of the natural course and potential treatment strategies on the basis of aneurysm biology under different flow conditions.

This protocol describes the steps for the creation of a rabbit model with two elastase-digested aneurysms with different hemodynamics (stump and bifurcation constellation). This allows the testing of novel endovascular devices in aneurysms with different angioarchitecture and hemodynamic conditions within a single animal.

在一只兔中产生两个具有不同血流动力学的囊状弹性蛋白酶消化动脉瘤

Preclinical animal models with hemodynamic, morphologic, and histologic characteristics close to human intracranial aneurysms play a key role in the ...