使用超声波血脑屏障破坏和锰增强MRI的脑功能成像
Summary
一个被描述为广泛的开放血脑屏障在鼠标使用微泡和超声技术。使用这种技术，锰，可管理的鼠脑。因为锰是一个磁共振造影剂，在去极化神经元的积累，这种方法能够使神经元的活动影像。
Abstract
虽然老鼠是主导的模型系统，为研究神经科学，脑功能成像在小鼠遗传和分子基础仍然是技术上的挑战。一种方法，激活诱导锰增强磁共振成像（MRI检查目的），已成功地用于映射在啮齿类动物的神经元活动1-5。在AIM MRI，锰2 +作用钙模拟，并在6,7去极化神经元累积。由于锰2 +缩短的T 1组织的财产，升高的神经元活动的地区，将加强在MRI。此外，锰2 +清除慢慢从活化地区，因此，可以进行刺激之前成像磁铁外，从而提高实验的灵活性。然而，因为锰2 +不容易穿过血脑屏障（BBB）的，需要打开血脑屏障限制使用的AIM MRI，尤其是在小鼠。
开放血脑屏障的工具之一是ULTrasound。虽然潜在的破坏性，如果超声结合管理与充气微泡（即超声造影剂），血脑屏障开放所需的声压是相当低的。可以使用这种超声和微泡的结合，可靠地打开，而不会造成组织损伤8-11血脑屏障。
在这里，一种方法是执行旨在利用微气泡和超声波打开血脑屏障的MRI。静脉注射perflutren微泡后，重点不突出的脉冲超声波束被剃光鼠标头3分钟。为简单起见，我们称这BBB的开放的技术与微泡和超声BOMUS 12。使用BOMUS打开整个血脑屏障的两个大脑半球，锰是管理整个鼠脑。轻轻镇静小鼠的实验刺激后，AIM MRI是用来映射神经反应。
至证明这种方法，本BOMUS和AIM MRI用于映射单方面的触须轻轻镇静小鼠13机械刺激。因为BOMUS可以打开整个两半球血脑屏障，无刺激大脑的一侧是用来控制背景非特异性刺激。由此产生的3D激活地图同意的桶领域皮质14的触须地区出版的申述。在超声开放血脑屏障的是快速，非侵入性的，可逆的，因此这种方法是适用于高吞吐量和/或纵向研究在清醒小鼠。
Protocol
1。组装和校准超声诊断系统直径宽，足以覆盖的小鼠大脑和中心频率在2 MHz的范围内与单元素的超声换能器的超声系统开始。传感器是由50分贝功率的放大器，它是连接到一个信号发生器产生超声波脉冲序列。 要校准的超声波系统的声压，使用与施加电压产生的声压水听器。传感器放置在一个以上的水听器的水箱。申请一个简单的脉冲（例如，换能器的频率在10周期与脉冲重复频率…
Discussion
在这里，一个方法是为无创性开放血脑屏障贯穿整个鼠脑超声和微泡（BOMUS）。随着BBB开放，锰2 +管理和激活诱导锰增强磁共振成像（MRI检查目的）被用来形象短时间刺激在轻轻镇静小鼠的神经元反应。
取得足够的血脑屏障开放与负峰值声压为0.36兆帕。请注意，这是在超声束的中心在头皮表面的压力。单元素的传感器的光束轮廓的测量表明，在光束边缘的声压是…
Declarações
The authors have nothing to disclose.
Acknowledgements
所有工作是在公爵在体内显微镜中心，美国国立卫生研究院/ NIBIB 国家生物医学技术资源中心（P41 EB015897）和国家癌症研究所的小动物成像资源计划（U24 CA092656）。 NSF研究生研究奖学金（2003014921），提供额外的支持。
Materials
| Name of the reagent | Company | Catalog number | Comments |
| Hydrophone | Sonora Medical Systems, Longmont, CA | SN S4-251 | |
| Translation stage | Newport Corporation, Irvine, CA | ||
| Ultrasound transducer | Olympus NDT, Inc., Waltham MA | A306S-SU | Review the manufacturer’s test sheet that accompanies the transducer to find the exact center frequency of that particular transducer, which may differ from the nominal frequency listed in the catalog. (e.g., the nominal frequency of our transducer was 2.25 MHz, but the actual center frequency was 2.15 MHz.) |
| Vevo Imaging Station | VisualSonics, Inc. Toronto, Canada | ||
| 50 dB power amplifier | E&I, Rochester, NY | model 240L | |
| Signal generator | Agilent Technologies, Santa Clara, CA | model 33220A | |
| MnCl2-(H2O)4 | Sigma | Molecular weight varies by batch, call manufacturer for exact measurement | |
| Perflutren lipid microspheres | Lantheus Medical Imaging, N. Billerica, MA | DEFINITY | |
| Microsphere agitator | Lantheus Medical Imaging, N. Billerica, MA | VIALMIX | |
| MR imaging coil | m2m Imaging Corp., Hillcrest, OH | 35 mm diameter quadrature transmit/receive volume coil | |
| MRI system | GE Healthcare, Milwaukee, WI | GE EXCITE console operating a 7-T horizontal bore magnet | |
| Image analysis environment | Visage Imaging, San Diego, CA, MathWorks, Natick MA | Amira MATLAB |
Referências
- Aoki, I. Detection of the anoxic depolarization of focal ischemia using manganese-enhanced MRI. Magnet. Reson. Med. 50, 7-12 (2003).
- Aoki, I. Dynamic activity-induced manganese-dependent contrast magnetic resonance imaging. DAIM MRI). Magnet. Reson. Med. 48, 927-933 (2002).
- Duong, T. Q., Silva, A. C., Lee, S. P., Kim, S. G. Functional MRI of calcium-dependent synaptic activity: Cross correlation with CBF and BOLD measurements. Magnet. Reson. Med. 43, 383-392 (2000).
- Lin, Y. J., Koretsky, A. P. Manganese ion enhances T-1-weighted MRI during brain activation: An approach to direct imaging of brain function. Magnet. Reson. Med. 38, 378-388 (1997).
- Lu, H. B. Cocaine-induced brain activation detected by dynamic manganese-enhanced magnetic resonance imaging (MEMRI). P. Natl. Acad. Sci. U.S.A. 104, 2489-2494 (2007).
- Drapeau, P., Nachshen, D. A. Manganese fluxes and manganese-dependent neurotransmitter release in presynaptic nerve-endings isolated from rat-brain. J. Physiol-London. 348, 493-510 (1984).
- Narita, K., Kawasaki, F., Kita, H. Mn and Mg influxes through Ca channels of motor-nerve Terminals are prevented by verapamil in Frogs. Brain Res. 510, 289-295 (1990).
- Hynynen, K., McDannold, N., Vykhodtseva, N., Jolesz, F. A. Noninvasive MR imaging-guided focal opening of the blood-brain barrier in rabbits. Radiology. 220, 640-644 (2001).
- Sheikov, N., McDannold, N., Vykhodtseva, N., Jolesz, F., Hynynen, K. Cellular mechanisms of the blood-brain barrier opening induced by ultrasound in presence of microbubbles. Ultrasound Med. Biol. 30, 979-989 (2004).
- McDannold, N., Vykhodtseva, N., Raymond, S., Jolesz, F. A., Hynynen, K. MRI-guided targeted blood-brain barrier disruption with focused ultrasound: Histological findings in rabbits. Ultrasound Med. Biol. 31, 1527-1537 (2005).
- McDannold, N., Vykhodtseva, N., Hynynen, K. Targeted disruption of the blood-brain barrier with focused ultrasound: association with cavitation activity. Phys. Med. Biol. 51, 793-807 (2006).
- Howles, G. P. Contrast-enhanced in vivo magnetic resonance microscopy of the mouse brain enabled by noninvasive opening of the blood-brain barrier with ultrasound. Magnet. Reson. Med. 64, 995-1004 (2010).
- Howles, G. P., Qi, Y., Johnson, G. A. Ultrasonic disruption of the blood-brain barrier enables in vivo functional mapping of the mouse barrel field cortex with manganese-enhanced MRI. Neuroimage. 50, 1464-1471 (2010).
- Woolsey, T. A., Welker, C., Schwartz, R. H. Comparative anatomical studies of sml face cortex with special reference to occurrence of barrels in layer-4. J. Comp. Neurol. 164, 79-94 (1975).
- Howles, G. P., Nouls, J. C., Qi, Y., Johnson, G. A. Rapid production of specialized animal handling devices using computer-aided design and solid freeform fabrication. J. Magnet. Reson. Imag. 30, 466-471 (2009).
- Paxinos, G., Franklin, K. B. J. . The mouse brain in stereotaxic coordinates. , (2001).
- Cross, D. J. Statistical mapping of functional olfactory connections of the rat brain in vivo. Neuroimage. 23, 1326-1335 (2004).
- Venot, A., Lebruchec, J. F., Golmard, J. L., Roucayrol, J. C. An automated-method for the normalization of scintigraphic images. J. Nucl. Med. 24, 529-531 (1983).
- Aoki, I., Naruse, S., Tanaka, C. Manganese-enhanced magnetic resonance imaging (MEMRI) of brain activity and applications to early detection of brain ischemia. Nmr. Biomed. 17, 569-580 (2004).
- Welker, E., Vanderloos, H. Quantitative correlation between barrel-field size and the sensory innervation of the whiskerpad – a comparative-study in 6 strains of mice bred for different patterns of mystacial vibrissae. J. Neurosci. 6, 3355-3373 (1986).
- McCasland, J. S., Woolsey, T. A. High-resolution 2-deoxyglucose mapping of functional cortical columns in mouse barrel cortex. J. Comp. Neurol. 278, 555-569 (1988).
- Irwin, S. Comprehensive observational assessment : A systematic quantitative procedure for assessing behavioral and physiologic state of mouse. Psychopharmacologia. 13, 222-257 (1968).
- Choi, J. J., Pernot, M., Small, S. A., Konofagou, E. E. Noninvasive, transcranial and localized opening of the blood-brain barrier using focused ultrasound in mice. Ultrasound Med. Biol. 33, 95-104 (2007).
- McDannold, N., Vykhodtseva, N., Hynynen, K. Use of ultrasound pulses combined with definity for targeted blood-brain barrier disruption: A feasibility study. Ultrasound Med. Biol. 33, 584-590 (2007).
- Silva, A. C., Lee, J. H., Aoki, L., Koretsky, A. R. Manganese-enhanced magnetic resonance imaging (MEMRI): methodological and practical considerations. Nmr. Biomed. 17, 532-543 (2004).
- Meiri, U., Rahamimoff, R. Neuromuscular transmission – inhibition by manganese ions. Science. 176, 308 (1972).
- Aschner, M., Guilarte, T. R., Schneider, J. S., Zheng, W. Manganese: Recent advances in understanding its transport and neurotoxicity. Toxicol. Appl. Pharm. 221, 131-147 (2007).
- Watanabe, T., Frahm, J., Michaelis, T. Manganese-enhanced MRI of the mouse auditory pathway. Magnet. Reson. Med. 60, 210-212 (2008).
- Yu, X., Wadghiri, Y. Z., Sanes, D. H., Turnbull, D. H. In vivo auditory brain mapping in mice with Mn-enhanced MRI. Nat. Neurosci. 8, 961-968 (2005).
- Yu, X. Statistical mapping of sound-evoked activity in the mouse auditory midbrain using Mn-enhanced MRI. Neuroimage. 39, 223-230 (2008).
Tags
Functional NeuroimagingUltrasonic Blood-brain Barrier DisruptionManganese-enhanced MRIMiceGenetic And Molecular Underpinnings Of NeuroscienceAIM MRINeuronal Activity MappingMn2+Calcium AnalogMRI EnhancementMn2+ ClearanceBlood-brain Barrier (BBB)UltrasoundGas-filled MicrobubblesUltrasound Contrast AgentsBBB Opening MethodPerflutren Microbubbles
Citar este artigo
Howles, G. P., Qi, Y., Rosenzweig, S. J., Nightingale, K. R., Johnson, G. A. Functional Neuroimaging Using Ultrasonic Blood-brain Barrier Disruption and Manganese-enhanced MRI. J. Vis. Exp. (65), e4055, doi:10.3791/4055 (2012).