Name: noninvasive assessment of cardiac abnormalities in experimental autoimmune myocarditis by magnetic resonance microscopy imaging in the mouse
Uploaded: 2014-06-20T15:00:00
Description: Watch this Scientific Journal Video about Noninvasive Assessment of Cardiac Abnormalities in Experimental Autoimmune Myocarditis by Magnetic Resonance Microscopy Imaging in the Mouse at JoVE.com

This work was supported by the National Institutes of Health (HL114669). CM is a recipient of a postdoctoral research fellowship grant awarded by the Myocarditis Foundation, NJ.

ETHICS STATEMENT:
All animal procedures were conducted in accordance with the guidelines for the Care and Use of Laboratory Animals and approved by the University of Nebraska-Lincoln, Lincoln, NE.
1. Induction of Experimental Autoimmune Myocarditis
<ol>
	<li>Prepare the peptide solution by dissolving Myhc-&#945; 334-352 in 1x phosphate-buffered saline to a final concentration of 2 mg/1.5 ml.</li>
	<li>Prepare the pertussis toxin (PT) by adding 1 m...

<ol>
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This study describes the MRM procedure and its utility as a non-invasive tool to ascertain cardiac abnormalities in mice affected with autoimmune myocarditis. Since the histologic features of EAM resemble postinfectious myocarditis of humans, mouse models are commonly employed to delineate the immune mechanisms of myocardial injuries23-25. However, the animals affected with myocarditis appear clinically normal, and the diagnosis is made based on histology at the termination of experiments7. The anim...

Heart failure is the leading cause of deaths, and myocarditis is one predominant cause of heart failure in young adolescents1. Most patients affected with myocarditis remain asymptomatic and the disease is spontaneously resolved2. However, 10-20% of those affected can develop chronic disease, leading to dilated cardiomyopathy (DCM)3. Various animal models have been developed to study the immune pathogenesis of myocarditis. The disease can be induced in myocarditis-susceptible A/J and Balb/c mice by immunizing the animals with cardiac myosin heavy chain (Myhc)-&#945; or its immunodominant peptide fragments or by infecting with pathogens like coxsackievirus B3 4-9. This study involves Myhc-&#945; 334-352-induced myocarditis in A/J mice. Despite showing myocardial infiltrations, the myocarditis-affected animals appear clinically normal; diagnosis is based on histological evaluation of hearts for inflammation7 and echocardiography10.
Magnetic resonance microscopy (MRM) is a commonly used method to obtain cardiovascular imaging with high resolution three-dimensional planes, permitting assessment of functional details to the level of minute blood vessels (up to 10 &#956;m diameter), but this level of resolving power is not achievable with the routine magnetic resonance imaging (MRI) scanning procedure, in which, the resolution is generally obtained up to 1 mm11-14. MRM offers an advantage as it permits acquisition of high-resolution images and also to derive performance parameters in the early time points of disease process14. Clinically, MRM imaging has been extensively applied to study the functional parameters of diseased heart, lung or brain15-17. In this study, the use of an MRM technique as a non-invasive tool to ascertain cardiac abnormalities in A/J mice affected with autoimmune myocarditis is shown. Specifically, the MRM imaging allows quantification of functional parameters such as left ventricular (LV) end-diastolic volume and ejection fraction (EF) with reasonable accuracy18. The definitions of respective parameters are: LV end diastolic volume, volume of blood in the left ventricle at the end of diastolic cycle, and ejection fraction, stroke volume/end-diastolic volume. The data analysis is performed using the freely available Segment software developed for processing DICOM-compliant cardiovascular images acquired by magnetic resonance scanners19. The data revealed an increase in thickness of the LV wall in the myocarditic animals, corresponding to a decrease in LV end-diastolic volume, stroke volume and ejection fraction, as compared with these functional parameters in healthy mice.

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			<td height="25" style="height:25px;width:509px;">Myhc-a 334-352 (DSAFDVLSFTAEEKAGVYK)</td>
			<td style="width:364px;">Neopeptide, Cambridge, MA</td>
			<td style="width:145px;"></td>
			<td style="width:167px;">Store at 4&#959;C</td>
		</tr>
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			<td height="25" style="height:25px;">CFA</td>
			<td style="width:364px;">Sigma Aldrich, St Louis, MO</td>
			<td style="width:145px;">5881</td>
			<td>Store at 4&#959;C</td>
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			<td height="25" style="height:25px;">MTB&#160; H37Rv extract&#160;</td>
			<td>Difco Laboratories, Detroit, MI</td>
			<td>231141</td>
			<td>Store at 4&#959;C</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">PT</td>
			<td>List Biologicals Laboratories, Campbell, CA</td>
			<td>181</td>
			<td>Store at 4&#959;C</td>
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			<td height="25" style="height:25px;">1x PBS&#160;</td>
			<td>Corning, Manassas, VA</td>
			<td>21-040-CV</td>
			<td>Store at 4&#959;C</td>
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			<td height="21" style="height:21px;">Isoflurane&#160;</td>
			<td>Piramal Healthcare, Mumbai, India</td>
			<td>NDC66794-013-25</td>
			<td></td>
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			<td height="21" style="height:21px;">Female A/J mice&#160;</td>
			<td>Jackson Laboratories, Bar Harbor, ME</td>
			<td>646</td>
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			<td height="21" style="height:21px;">Leur-lok sterile 1 ml syrringe</td>
			<td>BD, Franklin Lakes, NJ</td>
			<td>309628</td>
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			<td height="21" style="height:21px;">Leur-lok sterile 3 ml syrringe</td>
			<td>BD, Franklin Lakes, NJ</td>
			<td>309657</td>
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			<td height="21" style="height:21px;">Sterile needle, 18 G</td>
			<td>BD, Franklin Lakes, NJ</td>
			<td>305195</td>
			<td></td>
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			<td height="21" style="height:21px;">Sterile needle, 27 1/2 G</td>
			<td>BD, Franklin Lakes, NJ</td>
			<td>305109</td>
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			<td height="21" style="height:21px;">3-way stopcock&#160;</td>
			<td>Smiths Medical ASD, Inc. Dublin, OH</td>
			<td>MX5311L</td>
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			<td height="21" style="height:21px;">Kerlix gauze bandage rolls&#160;</td>
			<td>Covidien, Mansfield, MA</td>
			<td>6720</td>
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			<td height="21" style="height:21px;">Kimwipes</td>
			<td>Kimberly-Clark Professional, Roswell, GA</td>
			<td>34155</td>
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			<td height="21" style="height:21px;">Protouch Stockinette&#160;</td>
			<td>Medline Industries, Mundelein, IL</td>
			<td>30-1001</td>
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			<td style="width:364px;">INOX tool Corporation</td>
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			<td height="21" style="height:21px;">Micro oven</td>
			<td style="width:364px;">GE Healthcare,&#160;</td>
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			<td height="21" style="height:21px;">ThermiPAQ hot and cold therapy system&#160;</td>
			<td>Theramics Corporation, Springfield, IL</td>
			<td style="width:145px;"></td>
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			<td height="21" style="height:21px;">Reptile heating lamp&#160;</td>
			<td>Energy Savers Unlimited, Inc. Carson, CA</td>
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			<td height="21" style="height:21px;">3M Transpore tapes&#160;</td>
			<td>Target Corporation, MN</td>
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			<td height="21" style="height:21px;">Up and Up Polymyxin B sulfate/Bacitracin/Neomycin sulfate antibiotic ointment</td>
			<td>Target Corporation, MN</td>
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			<td height="21" style="height:21px;">North Safety DeciDamp-2PVC foam ear plugs</td>
			<td style="width:364px;">North Safety Products, Smithfield, RI</td>
			<td style="width:145px;"></td>
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			<td height="21" style="height:21px;">Cotton tipped applicator, 6&#8217;&#8217; wooden stem&#160;</td>
			<td>Jorgensen Laboratories, Inc. Loveland, CO</td>
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			<td height="21" style="height:21px;">Anesthesia induction chamber&#160;</td>
			<td>Summit Anesthesia Solutions, Ann Harbor, MI</td>
			<td style="width:145px;"></td>
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			<td height="21" style="height:21px;">Summit Anesthesia Support system for regulating flow of anesthesia&#160;</td>
			<td>Summit Anesthesia Solutions, Ann Harbor, MI</td>
			<td style="width:145px;"></td>
			<td></td>
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			<td height="21" style="height:21px;">Specially designed animal holder</td>
			<td>Agilent Technologies, Santa Clara, CA</td>
			<td style="width:145px;"></td>
			<td></td>
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			<td height="21" style="height:21px;">Bickford&#160;Omnicon F/Air&#160;anesthesia gas filter unit&#160;</td>
			<td>A.M. Bickford, Inc. Wales Center, NY</td>
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			<td></td>
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			<td height="21" style="height:21px;">Pulse-oximeter module, MR compatible small animal monitoring and gating system&#160;</td>
			<td>Small Animal Instruments, Inc. Stony Brook, NY</td>
			<td style="width:145px;"></td>
			<td></td>
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			<td height="21" style="height:21px;">Oxygen cylinder&#160;</td>
			<td>Matheson-Tri Gas, North-Central Zone, Lincoln, NE</td>
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			<td height="21" style="height:21px;">Gas regulator&#160;</td>
			<td>Western Medica, West Lake, OH</td>
			<td style="width:145px;"></td>
			<td></td>
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			<td height="21" style="height:21px;">Signal breaking module, MR compatible small animal monitoring and gating system</td>
			<td>Small Animal Instruments, Inc. Stony Brook, NY</td>
			<td style="width:145px;"></td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;">9.4 T (400 MHZ) 89 mm vertical core bore MR scanner&#160;</td>
			<td>Agilent Technologies, Santa Clara, CA</td>
			<td style="width:145px;"></td>
			<td></td>
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			<td height="21" style="height:21px;">4-cm millipede micro-imaging RF coil&#160;</td>
			<td>Agilent Technologies, Santa Clara, CA</td>
			<td style="width:145px;"></td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;">SAM PC monitor&#160;</td>
			<td>Small Animal Instruments, Inc. Stony Brook, NY</td>
			<td style="width:145px;"></td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;">Quantitative Medical Image analysis software&#160;</td>
			<td colspan="3">http://segment.heiberg.se;&#160; Segment v1.8 R1430,&#160; Medviso, Oresunds region, Sweden</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Matlab software&#160;</td>
			<td>The Mathworks, Inc.&#160; Natick, MA</td>
			<td style="width:145px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Computer-Unix operating system</td>
			<td style="width:364px;"></td>
			<td style="width:145px;"></td>
			<td></td>
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	</tbody>
</table>

noninvasive assessment of cardiac abnormalities in experimental autoimmune myocarditis by magnetic resonance microscopy imaging in the mouse

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events of myocardial injuries, various mouse models of myocarditis have been widely used. This study involved experimental autoimmune myocarditis (EAM) induced with cardiac myosin heavy chain (Myhc)-&#945; 334-352 in A/J mice; the affected animals develop lymphocytic myocarditis but with no apparent clinical signs. In this model, the utility of magnetic resonance microscopy (MRM) as a non-invasive modality to determine the cardiac structural and functional changes in animals immunized with Myhc-&#945; 334-352 is shown. EAM and healthy mice were imaged using a 9.4 T (400 MHz) 89 mm vertical core bore scanner equipped with a 4 cm millipede radio-frequency imaging probe and 100 G/cm triple axis gradients. Cardiac images were acquired from anesthetized animals using a gradient-echo-based cine pulse sequence, and the animals were monitored by respiration and pulse oximetry. The analysis revealed an increase in the thickness of the ventricular wall in EAM mice, with a corresponding decrease in the interior diameter of ventricles, when compared with healthy mice. The data suggest that morphological and functional changes in the inflamed hearts can be non-invasively monitored by MRM in live animals. In conclusion, MRM offers an advantage of assessing the progression and regression of myocardial injuries in diseases caused by infectious agents, as well as response to therapies.

In this report, the utility of MRM technique as a non-invasive modality to determine the structural and functional changes in the hearts of animals affected with EAM is shown. Myocarditis was induced in A/J mice by immunizing the animals with Myhc-&#945; 334-352 in CFA7, and the animals were subjected to MRM experiments on day 21 post-immunization. The MRM imaging was performed on live animals under isoflurane anesthesia at 9.4 T (400 MHz for protons) using an 89&#160;mm vertical-bore magnet equipped with trip...

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Noninvasive Assessment of Cardiac Abnormalities in Experimental Autoimmune Myocarditis by Magnetic Resonance Microscopy Imaging in the Mouse

This study demonstrates the successful establishment of magnetic resonance microscopy imaging as a non-invasive tool to assess the cardiac abnormalities in mice affected with autoimmune myocarditis. The data indicate that the technique can be used to monitor the disease-progression in live animals.

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events ...

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Research

JoVE Journal

Medicine

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.

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 ...

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.

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

Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases

Diffusion tensor imaging (DTI) techniques provide information on the microstructural processes of the cerebral white matter (WM) in vivo. The present applications are designed to investigate differences of WM involvement patterns in different brain diseases, especially neurodegenerative disorders, by use of different DTI analyses in comparison with matched controls. 	
DTI data analysis is performed in a variate fashion, i.e. voxelwise comparison of regional diffusion direction-based metrics such as fractional anisotropy (FA), together with fiber tracking (FT) accompanied by tractwise fractional anisotropy statistics (TFAS) at the group level in order to identify differences in FA along WM structures, aiming at the definition of regional patterns of WM alterations at the group level. Transformation into a stereotaxic standard space is a prerequisite for group studies and requires thorough data processing to preserve directional inter-dependencies. The present applications show optimized technical approaches for this preservation of quantitative and directional information during spatial normalization in data analyses at the group level. On this basis, FT techniques can be applied to group averaged data in order to quantify metrics information as defined by FT. Additionally, application of DTI methods, i.e. differences in FA-maps after stereotaxic alignment, in a longitudinal analysis at an individual subject basis reveal information about the progression of neurological disorders. Further quality improvement of DTI based results can be obtained during preprocessing by application of a controlled elimination of gradient directions with high noise levels.	
In summary, DTI is used to define a distinct WM pathoanatomy of different brain diseases by the combination of whole brain-based and tract-based DTI analysis.

Diffusion tensor imaging (DTI) basically serves as an MRI-based tool to identify in vivo the microstructure of the brain and pathological processes due to neurological disorders within the cerebral white matter. DTI-based analyses allow for application to brain diseases both at the group level and in single subject data.

Diffusion tensor imaging (DTI) techniques provide information on the microstructural processes of the cerebral white matter (WM) in vivo. The present ...

Implanting Glass Spinal Cord Windows in Adult Mice with Experimental Autoimmune Encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) in adult rodents is the standard experimental model for studying autonomic demyelinating diseases such as multiple sclerosis. Here we present a low-cost and reproducible glass window implantation protocol that is suitable for intravital microscopy and studying the dynamics of spinal cord cytoarchitecture with subcellular resolution in live adult mice with EAE. Briefly, we surgically expose the vertebrae T12-L2 and construct a chamber around the exposed vertebrae using a combination of cyanoacrylate and dental cement. A laminectomy is performed from T13 to L1, and a thin layer of transparent silicone elastomer is applied to the dorsal surface of the exposed spinal cord. A modified glass cover slip is implanted over the exposed spinal cord taking care that the glass does not directly contact the spinal cord. To reduce the infiltration of inflammatory cells between the window and spinal cord, anti-inflammatory treatment is administered every 2 days (as recommended by ethics committee) for the first 10 days after implantation. EAE is induced only 2-3 weeks after the cessation of anti-inflammatory treatment.
Using this approach we successfully induced EAE in 87% of animals with implanted windows and, using Thy1-CFP-23 mice (blue axons in dorsal spinal cord), quantified axonal loss throughout EAE progression. Taken together, this protocol may be useful for studying the recruitment of various cell populations as well as their interaction dynamics, with subcellular resolution and for extended periods of time. This intravital imaging modality represents a valuable tool for developing therapeutic strategies to treat autoimmune demyelinating diseases such as EAE.

We describe a method for implanting and maintaining glass windows over the exposed spinal cords of adult mice for studying experimental autoimmune encephalomyelitis. These windows provide chronic optical access to the spinal cord for monitoring cell dynamics at the subcellular level in live animals using two-photon microscopy.

Experimental autoimmune encephalomyelitis (EAE) in adult rodents is the standard experimental model for studying autonomic demyelinating diseases such as ...

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.

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

Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable noninvasive method is essential to assess real-time cardiac morphological and functional changes in animal models of heart disease. Transthoracic echocardiography represents an important tool for noninvasive assessment of cardiac structure and function2. Here we used a high-resolution ultrasound imaging system to monitor myocardial remodeling and heart failure progression over time in a mouse model of TAC. B-mode, M-mode, and Doppler imaging were used to precisely assess cardiac hypertrophy, ventricular dilatation, and functional deterioration in mice following TAC. Color and pulse wave (PW) Doppler imaging was used to noninvasively measure pressure gradient across the aortic constriction created by TAC and to assess transmitral blood flow in mice. Thus transthoracic echocardiographic imaging provides comprehensive noninvasive measurements of cardiac dimensions and function in mouse models of heart disease.

The goal of this protocol is to noninvasively assess cardiac structural and functional changes in a mouse model of heart disease created by transverse aortic constriction, using B- and M-mode echocardiography and color/pulse wave Doppler imaging.

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable ...

In Vivo Tracking of Edema Development and Microvascular Pathology in a Model of Experimental Cerebral Malaria Using Magnetic Resonance Imaging

Cerebral malaria is a sign of severe malarial disease and is often a harbinger of death. While aggressive management can be life-saving, the detection of cerebral malaria can be difficult. We present an experimental mouse model of cerebral malaria that shares multiple features of the human disease, including edema and microvascular pathology. Using magnetic resonance imaging (MRI), we can detect and track the blood-brain barrier disruption, edema development, and subsequent brain swelling. We describe multiple MRI techniques that can visualize these pertinent pathological changes. Thus, we show that MRI represents a valuable tool to visualize and track pathological changes, such as edema, brain swelling, and microvascular pathology, in vivo.

In Vivo Tracking of Edema Development and Microvascular Pathology in a Model of Experimental Cerebral Malaria Using Magnetic Resonance Imaging

We describe a mouse model of experimental cerebral malaria and show how inflammatory and microvascular pathology can be tracked in vivo using magnetic resonance imaging.

Cerebral malaria is a sign of severe malarial disease and is often a harbinger of death. While aggressive management can be life-saving, the detection of ...

Quantitative Visualization of Leukocyte Infiltrate in a Murine Model of Fulminant Myocarditis by Light Sheet Microscopy

Light-sheet fluorescence microscopy (LSFM), in combination with chemical clearing protocols, has become the gold standard for analyzing fluorescently labelled structures in large biological specimens, and is down to cellular resolution. Meanwhile, the constant refinement of underlying protocols and the enhanced availability of specialized commercial systems enable us to investigate the microstructure of whole mouse organs and even allow for the characterization of cellular behavior in various live-cell imaging approaches. Here, we describe a protocol for the spatial whole-mount visualization and quantification of the CD45+ leukocyte population in inflamed mouse hearts. The method employs a transgenic mouse strain (CD11c.DTR)that has recently been shown to serve as a robust, inducible model for the study of the development of fulminant fatal myocarditis, characterized by lethal cardiac arrhythmias. This protocol includes myocarditis induction, intravital antibody-mediated cell staining, organ preparation, and LSFM with subsequent computer-assisted image post-processing. Although presented as a highly-adapted method for our particular scientific question, the protocol represents the blueprint of an easily adjustable system that can also target completely different fluorescent structures in other organs and even in other species.

Here, we describe a light-sheet microscopy approach to visualize the cardiac CD45+ leukocyte infiltrate in a murine model of aseptic fulminant myocarditis, which is induced by the intratracheal diphtheria toxin treatment of CD11c.DTR mice.

Light-sheet fluorescence microscopy (LSFM), in combination with chemical clearing protocols, has become the gold standard for analyzing fluorescently ...

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.

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 ...

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous studies have shown that abnormal blood flow may be associated with systemic vascular risk. Thus, PC-MRI can facilitate the translation of data obtained from animal models of cardiovascular diseases to pertinent clinical investigations. In this report, we describe the procedure for measuring blood flow in the common carotid artery (CCA) of rats using cine-gated PC-MRI and discuss relevant analysis methods. This procedure can be performed in a live, anesthetized animal and does not require euthanasia after the procedure. The proposed scanning parameters yield repeatable measurements for blood flow, indicating excellent reproducibility of the results. The PC-MRI procedure described in this article can be used for pharmacological testing, pathophysiological assessment, and cerebral hemodynamics evaluation.

The overall goal of this procedure is to measure the blood flow in the rat common carotid artery by using noninvasive phase contrast magnetic resonance imaging.

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