We are grateful for funding from the British Heart Foundation to TK and to the UK Medical Research Council for a postgraduate research studentship to GB.

All components of this study were carried out in accordance with the UK Animals (Scientific Procedures) Act, 1986, and with the approval of the University of Cambridge Ethical Review Panel.
1. Animal Preparation
<ol>
	<li>Induce infarcts with a surgical intervention7,8. For measuring at the acute stage, perform imaging 24 hr after intervention.</li>
	<li>Prepare a thin syringe tubing for drug delivery with a 25 G needle at one extremity and a syringe with a 25 G needle at the other end. The length of the line should be enough to allow the injection from outside the magnet&#8217;s bore (approximately&#160;1.5 m).</li>
	<li>Prepare a solution diluting Gadovist in saline. Load a syringe with the right amount of solution to achieve 3 mmol/kg adjusted for mouse bodyweight. Keep the injection volume between 50-100 &#181;l.</li>
	<li>Prefill the line with the Gadovist solution. To avoid blood clotting, fill the extremity of the line close to the cannula with heparin saline.</li>
	<li>Place the mouse in the induction box for anesthesia with 3% isoflurane in O2&#160;1 L/min for 3-5 min as necessary. Correct anesthesia depth can be identified with the slowing breath rate, which should decrease to less than 70 bpm.</li>
	<li>Cannulate the tail vein using the line previously prepared, use surgical tape to keep the needle in place during the procedure.</li>
</ol>
2. Animal Positioning and Monitoring
<ol>
	<li>Place the mouse on the MRI bed, delivering 1-2% isoflurane in 1 L/min O2 for anesthesia maintenance as required. Maintain respiration rates between 20-70 bpm.</li>
	<li>Ensure the center of the MRI coil is located over the mouse heart position.</li>
	<li>Monitor respiration by placing a respiratory pillow sensor slightly below the diaphragm. Use a rectal thermometer with a prelubricated cover slip to monitor core temperature. Ensure that temperature is kept constant during the scans at 37&#177;2 &#176;C.</li>
	<li>For ECG monitoring, place three electrodes on the anterior paws and on the left rear paw, making sure that the palm of the toe is completely open. Choose the pair of electrodes achieving the best signal quality to derive the ECG. Twist the ECG cables together, to insure that they do not form resonant circuits at the MRI resonant frequency, which would severely corrupt the ECG signal when running pulse sequences.</li>
	<li>Ensure the electrodes are firmly attached to the bed using tape. The electrodes and the nose cone will hold the animal in place during the whole procedure.</li>
	<li>Position a water-heated blanket over the mouse, encapsulating the monitoring and coil leads to maintain body temperature.</li>
	<li>Align the laser of the bed with the heart position; use the anterior toes line as a landmark. Position this in the magnet isocenter using an automatic bed.</li>
	<li>Run the standard adjustments for the MRI system.</li>
	<li>Set the monitoring equipment to detect the R-wave in the ECG. Adjust the thresholds for each mouse and within imaging sessions so that there is reliable triggering.</li>
</ol>
3. MRI
<ol>
	<li>Acquire a pilot image to plan the multiplanar pilot images.</li>
	<li>Identify the heart in the image, most easily by its flow artifacts. If the images show the mouse is not well centered in the coil or the isocenter, retract the bed and repeat positioning.</li>
	<li>Acquire a fast gradient echo (GE) image with five slices per orientation and a 3 cm field of view (FOV)&#160;with ECG gating turned on.</li>
	<li>Run an ungated 3D scan centered on the heart for PET coregistration (see Table 1 for scan parameters). While this scan is running, plan the successive scans.</li>
	<li>Plan a four chamber (4 ch) view scan (see Table 1 for scan parameters). This should cut through the apex and the tricuspid and mitral valves, showing all 4 chambers.</li>
	<li>Plan a two chamber (2 ch) view (see Table 1 for scan parameters). It should cut through the apex and the tricuspid valve, showing the left atrium and ventricle.</li>
	<li>Crosscheck the geometry of the two long-axis views. If the slice planning is sub-optimal, repeat the scan.</li>
	<li>Plan a stack of short axis slices (see Table 1 for scan parameters) orthogonal to both the 4 ch and to the 2 ch view. Cover the whole heart, starting from the first apical slice without blood pool until the first basal slice without any RV. Slices should be equally spaced with no gaps.</li>
</ol>
4. Late Gadolinium Enhancement
<ol>
	<li>Increase blank time for gating to acquire every other heart beat (TR = 550-750 msec). A delay must be applied such that acquisition is performed at the end-diastolic phase of the ECG.</li>
	<li>Perform a low-resolution version of the LGE sequence (see Table 1 for scan parameters) before the injection in order to check that the gating is correct and no flow artifacts are present. If flow artifacts are present in the diastolic phase, increasing the delay slightly (i.e. imaging at the very early stage of systole) will get rid of them.</li>
	<li>Perform the injection of the Gadovist solution slowly and steadily over 15 sec.</li>
	<li>Initiate LGE imaging (see Table 1 for scan parameters) after the injection. Good contrast is achieved when imaging within the first 15 min.</li>
</ol>
5. PET Imaging
<ol>
	<li>Transfer the MRI bed to the PET scanner leaving the receiver in place and firmly anchor it to the PET bed support. Connect the anesthetic and monitoring equipment.</li>
	<li>Position the heart in the center of the PET field of view moving the bed only axially.</li>
	<li>Acquire a single-pass transmission scan with a germanium source.</li>
	<li>Extract 10-30 Mbq of radioactively labeled FDG from its container with a syringe. Take necessary care with radioactive material. Measure the activity with a well counter. A good injection volume for mice ranges between 50-100 &#181;l, if the volume is too small, dilute the solution with saline.</li>
	<li>Start the emission scan, set to acquire list-mode gated PET for 45 min. Contemporaneously, inject the tracer slowly and steadily over 15 sec. Flush the line with enough saline to deliver the whole of the radioactive tracer.</li>
	<li>For animal health, do not to exceed 300 &#181;l with the three injections (i.e. Gadovist, FDG, flush).</li>
	<li>Place the syringe back in the well counter to measure the residual activity.</li>
	<li>Follow local rules throughout for handling radioactive material.</li>
</ol>
6. MRI Segmentation
<ol>
	<li>Load the Cine-MRI images in Segment v1.9&#160;9.</li>
	<li>Run the automatic tools for segmentation. Starting from a point inside the ventricle, these will inflate the estimated ventricle walls until the best match is found.</li>
	<li>Delineate the LV and the RV manually at end systole (ES) and end diastole (ED), defined respectively as the frames with the maximal and with the minimal global LV volume. Exclude the papillary muscles and trabeculations throughout. Do not adjust image contrast, as inconsistency in the contrast leads to a different interpretation of partial volume effects.</li>
	<li>Delineate manually the epicardium at ES and ED for LV mass calculations, as shown in Figure 6. The cardiac muscle is incompressible, so the LV mass must be consistent in ES and ED. If the difference is more than 5% operator error is likely and these should be reviewed.</li>
	<li>At the base of the ventricles, use a straight line to discriminate ventricles from atria as shown in Figure 6, identifying the angle of the slice with the help of the long-axis views.</li>
	<li>Cross-check the segmentation on the long-axis views.</li>
	<li>Delineate the scar area on the LGE images. Divide the scar volume by the LV mass derived in the cine imaging to obtain the infarct as a percentage of the LV.</li>
</ol>
7. PET Analysis and Coregistration with MRI
<ol>
	<li>Reconstruct the PET images using a 3D filtered backprojection algorithm and export data to Nifti format (http://nifti.nimh.nih.gov/) showing standard uptake values.</li>
	<li>Transform all the PET images using the fixed transformation matrix between the PET and the MRI system. If the matrix is not known, fill a geometrical phantom with radioactive material and perform an MRI, then move the bed to the PET and perform an emission scan. The matrix obtained to transform the PET to the MRI image is the standard matrix to go from the PET to the MRI system.</li>
	<li>Register the average PET image to the 3D MRI using SPM-mouse bulk coregistration tool10.</li>
	<li>Stack the slices from Cine-MRI to obtain a 3D reconstruction, interpolate to obtain 0.3 mm isotropic resolution. Register the end-diastolic PET volume to the end-diastolic MRI volume using SPM-Mouse coregistration tools. Use the same matrix for all the other heart phases.</li>
	<li>To evaluate PET infarct size, choose 50% of the maximum intensity in the heart to discriminate between infarcted and noninfarcted voxels. Express infarcted voxels as a percentage of the LV.</li>
</ol>

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S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+isolated+working+mouse+heart:+methodological+considerations.">The isolated working mouse heart: methodological considerations.</a> Pfl&#252;gers Arch. 437, 979-985 (1999).</li><li>Epstein, F. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MR+in+mouse+models+of+cardiac+disease.">MR in mouse models of cardiac disease.</a> NMR Biomed. 20, 238-255 (2007).</li><li>Schneider, J. E., Wiesmann, F., Lygate, C. A., Neubauer, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+to+perform+an+accurate+assessment+of+cardiac+function+in+mice+using+high-resolution+magnetic+resonance+imaging.">How to perform an accurate assessment of cardiac function in mice using high-resolution magnetic resonance imaging.</a> J. Cardiov. Magn. Reson. 8, 693-701 (2006).</li><li>Buonincontri, G., Methner, C., Krieg, T., Carpenter, T. A., Sawiak, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+fast+protocol+for+infarct+quantification+in+mice.">A fast protocol for infarct quantification in mice.</a> J. Magn. Reson. Imaging. , (2013).</li><li>Methner, C., Schmidt, K., Cohen, M. V., Downey, J. 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There is nothing to disclose.

PET/MRI is a comprehensive measurement method for the noninvasive and longitudinal evaluation of systolic function, tissue viability and specific metabolic markers in mouse models of myocardial infarction. Here we have described a protocol for performing MRI and PET sequentially, where coregistration is simplified by the transfer of the same bed between systems. This strategy, also adopted by manufacturers of clinical systems11, does not require a combined PET/MRI scanner and can be performed with standard equ...

In order to measure the efficacy of new treatment strategies for myocardial infarction (MI) in preclinical studies, the assessment of the acute stage as well as long-term outcome is required1. Methods such as histopathology, intracardiac catheters2, and ex vivo heart models3 are commonly used for preclinical studies in mice. It is impossible, however, to follow up treatment with ex vivo&#160;or highly invasive methods. Noninvasive measurement techniques as in vivo&#160;magnetic resonance imaging (MRI) and positron emission tomography (PET) allow longitudinal experimental designs for disease staging in single subjects. Cine-MRI is used to derive global functional parameters such as left ventricular mass (LVM), ejection fraction (EF) and cardiac output (CO). In addition, after the injection of a gadolinium contrast agent, due to impaired perfusion and washout in the infarction, tissue viability can be assessed with late gadolinium enhancement (LGE) MRI. Complementarily, PET offers a sensitive measure of radiolabeled molecules in order to assess tissue metabolism. The high accuracy of these techniques permits significant reductions in the number of animals required for testing new drugs targeting MI.
The PET and MRI procedures are involved, and without a carefully designed protocol reproducibility is hard to maintain. Procedures established in the clinic for patients require substantial modification for use in mice, due to their considerably faster heart rate and smaller dimensions of the heart4. There is wide variation between individual subjects, both at baseline and in response to induced injury, so a considerable number of mice are needed to establish treatment efficacy.
In this report, we describe our method for sequential PET/MRI imaging of the mouse heart. Both modalities use intravenous contrast agents, which are delivered through the tail vein. MRI consists of standard assessment with Cine-MRI5&#160;with an optimal protocol for LGE as described in our previous work6. The entire MRI procedure lasts 30 min. We have obtained consistent fittings for the beds of our instruments so it is possible to transfer the animal on a platform with the same monitoring and anesthetic delivery apparatus between the machines. The PET scan lasts 45 min with in situ injection once the scan is started. The final step is to measure the parameters from both MRI and PET images following coregistration.

<table><tbody><tr><td>Gadovist</td><td>Bayer Schering Pharma</td><td>PL 00010/0535</td><td></td></tr><tr><td>FDG</td><td>IBA Molecular</td><td></td><td></td></tr><tr><td>Equipment</td><td></td><td></td><td></td></tr><tr><td>Bruker BioSpec 47/40</td><td>Bruker</td><td></td><td></td></tr><tr><td>Bruker mouse bed</td><td>Bruker</td><td></td><td>This bed includes tubing for anesthesia delivery and scavenging.</td></tr><tr><td>12 cm diameter birdcage transmitter</td><td>Bruker</td><td>T5346</td><td></td></tr><tr><td>2 cm diameter surface coil receiver</td><td>Bruker</td><td>T7027</td><td></td></tr><tr><td>Red Dot Neonatal monitoring electrodes</td><td>3M</td><td>P/N: 2330</td><td></td></tr><tr><td>Monitoring equipment</td><td>SA Systems</td><td></td><td>The monitoring kit includes respiratory pillow and rectal probe for temperature measurements.</td></tr><tr><td>Anesthesia equipment</td><td>General Anesthetic Services</td><td></td><td></td></tr><tr><td>Induction box</td><td>Vet Tech Solutions LTD</td><td></td><td></td></tr><tr><td>Cambridge split-magnet PET/MRI scanner</td><td>University of Cambridge</td><td></td><td>A custom built PET/MRI scanner&lt;sup&gt;22&lt;/sup&gt; was used to perform the PET, its PET performance similar to an F120 micropet scanner&lt;sup&gt;23&lt;/sup&gt;</td></tr><tr><td>Segment software</td><td>Medviso, Lund University</td><td></td><td>Freely available</td></tr><tr><td>SPM-mouse</td><td>University of Cambridge</td><td></td><td>Freely available</td></tr></tbody></table>

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.

One of the advantages of using MRI is that a longitudinal design can be used in order to stage disease. This is especially important when evaluating novel compounds, as the time course of effect may not be known. Variations in heart volumes due to the disease progression in the same animal are shown in Figure 4. The figure clearly shows the effects of remodeling post myocardial infarction.
Correct slice geometry is crucial for the success of a cardiac MRI experiment. Represent...

Watch this Scientific Journal Video about MRI and PET in Mouse Models of Myocardial Infarction at JoVE.com

MRI and PET in Mouse Models of Myocardial Infarction

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.

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 ...

mri-and-pet-in-mouse-models-of-myocardial-infarction

Universidad de Cartagena UDEC

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JoVE Journal

Medicine

11.7K Views.  Unversity of Cambridge. 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.

Video: MRI and PET in Mouse Models of Myocardial Infarction

A Murine Model of Myocardial Ischemia-reperfusion Injury through Ligation of the Left Anterior Descending Artery

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms at work during MI and developing effective therapeutic approaches requires methodology to reproducibly simulate the clinical incidence and reflect the pathophysiological changes associated with MI. Here, we describe a surgical method to induce MI in mouse models that can be used for short-term ischemia-reperfusion (I/R) injury as well as permanent ligation. The major advantage of this method is to facilitate location of the left anterior descending artery (LAD) to allow for accurate ligation of this artery to induce ischemia in the left ventricle of the mouse heart. Accurate positioning of the ligature on the LAD increases reproducibility of infarct size and thus produces more reliable results. Greater precision in placement of the ligature will improve the standard surgical approaches to simulate MI in mice, thus reducing the number of experimental animals necessary for statistically relevant studies and improving our understanding of the mechanisms producing cardiac dysfunction following MI. This mouse model of MI is also useful for the preclinical testing of treatments targeting myocardial damage following MI.

We introduce a surgical method to induce experimental ischemia/reperfusion (I/R) injury to simulate myocardial infarction (MI) in mouse models that allows for more clarity in positioning of the ligation on the left anterior descending artery (LAD) to increase the reproducibility of MI experiments in mice.

Un modello murino di ischemia miocardica e riperfusione lesioni da legatura della arteria discendente anteriore sinistra

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms ...

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Medicina

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD).

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

This method outlines the use of Quantum Micro-Computed Tomography (MicroCT) to assess cardiac morphology, function, perfusion, metabolism and viability with iodinated contrast agent in mice with experimentally-induced myocardial ischemia. The technique can be applied for non-destructive high-throughput longitudinal in vivo imaging of various animal models of human heart disease.

In Vivo quantitativa valutazione della struttura del miocardio, la funzione, la perfusione e sostenibilità Utilizzando cardiaca micro-tomografia computerizzata

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that ...

Bioingegneria

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.

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.

La valutazione non invasiva della Cardiac Anomalie in Experimental Autoimmune miocardite da Risonanza Magnetica Imaging Microscopy nel 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 ...

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.

Simultanea Imaging PET / MRI Durante mouse cerebrale ipossia-ischemia

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

PET Imaging of Neuroinflammation Using [11C]DPA-713 in a Mouse Model of Ischemic Stroke

Neuroinflammation is central to the pathological cascade following ischemic stroke. Non-invasive molecular imaging methods have the potential to provide critical insights into the temporal dynamics and role of certain neuroimmune interactions in stroke. Specifically, Positron Emission Tomography (PET) imaging of translocator protein 18 kDa (TSPO), a marker of activated microglia and peripheral myeloid-lineage cells, provides a means to detect and track neuroinflammation in vivo. Here, we present a method to accurately quantify neuroinflammation using [11C]N,N-Diethyl-2-[2-(4-methoxyphenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl]acetamide ([11C]DPA-713), a promising second generation TSPO-PET radiotracer, in distal middle cerebral artery occlusion (dMCAO) compared to sham-operated mice. MRI was performed 2 days post-dMCAO surgery to confirm stroke and define the infarct location and volume. PET/Computed Tomography (CT) imaging was carried out 6 days post-dMCAO to capture the peak increase in TSPO levels following stroke. Quantitation of PET images was conducted to assess the uptake of [11C]DPA-713 in the brain and spleen of dMCAO and sham mice to assess central and peripheral levels of inflammation. In vivo [11C]DPA-713 brain uptake was confirmed using ex vivo autoradiography.

PET Imaging of Neuroinflammation Using [11C]DPA-713 in a Mouse Model of Ischemic Stroke

Positron Emission Tomography (PET) imaging of translocator protein 18 kDa (TSPO) provides a non-invasive means to visualize the dynamic role of neuroinflammation in the development and progression of brain diseases. This protocol describes TSPO-PET and ex vivo autoradiography to detect neuroinflammation in a mouse model of ischemic stroke.

Imaging del Neuroinflammation utilizzando [11C] DPA-713 in un modello murino di ictus ischemico per animali

Neuroinflammation is central to the pathological cascade following ischemic stroke. Non-invasive molecular imaging methods have the potential to provide ...

Murine Myocardial Infarction Model using Permanent Ligation of Left Anterior Descending Coronary Artery

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine models of MI with permanent ligation of left-anterior descending (LAD) coronary artery closely mimics MI in humans. Murine models benefit from the extensive genetic engineering available nowadays. Here we propose a reproducible murine surgical model of myocardial infarction by permanent LAD coronary ligation. Our technique comprises anesthesia with ketamine/xylazine that can be rapidly reversed by administration of an antagonist, intubation without tracheotomy for mechanical-assisted ventilation, ventilation with application of extrinsic positive end-expiratory pressure (PEEP) to avoid alveolar collapse, a thoracotomy method limiting to the minimum surgical lesions made to skeletal muscles, and lung inflation without thoracentesis. This method is sparsely invasive, reproducible and reduces post-surgery mortality and complications.

Herein we describe a surgical procedure showing how to achieve permanent ligation of the left-anterior descending coronary artery in mice. This model is of high relevance to investigate the pathophysiology of myocardial infarction and the concomitant biological processes.

Modello di infarto miocardico Murine utilizzando la legatura permanente dell'arteria coronaria discendente anteriore sinistra

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine ...

A Cryoinjury Model to Study Myocardial Infarction in the Mouse

The use of animal models is essential for developing new therapeutic strategies for acute coronary syndrome and its complications. In this article, we demonstrate a murine cryoinjury infarct model that generates precise infarct sizes with high reproducibility and replicability. In brief, after intubation and sternotomy of the animal, the heart is lifted from the thorax. The probe of a handheld liquid nitrogen delivery system is applied onto the myocardial wall to induce cryoinjury. Impaired ventricular function and electrical conduction can be monitored with echocardiography or optical mapping. Transmural myocardial remodeling of the infarcted area is characterized by collagen deposition and loss of cardiomyocytes. Compared to other models (e.g., LAD-ligation), this model utilizes a handheld liquid nitrogen delivery system to generate more uniform infarct sizes.

This article demonstrates a model to study cardiac remodeling after myocardial cryoinjury in mice.

Un modello di criolesionismo per studiare l'infarto miocardico nel mouse

The use of animal models is essential for developing new therapeutic strategies for acute coronary syndrome and its complications. In this article, we ...

Induction of Myocardial Infarction and Myocardial Ischemia-Reperfusion Injury in Mice

Acute myocardial infarction is a common cardiovascular disease with high mortality. Myocardial reperfusion injury can counteract the beneficial effects of heart reflow and induce secondary myocardial injury. A simple and reproducible model of myocardial infarction and myocardial ischemia-reperfusion injury is a good tool for researchers. Here, a customizable method to create a myocardial infarction (MI) model and MIRI by precision ligation of the left anterior descending coronary artery (LAD) through micromanipulation is described. Accurate and reproducible ligature positioning of the LAD helps obtain consistent results for heart injury. ST-segment changes can help to identify model accuracy. The serum level of cardiac troponin T (cTnT) is used to assess the myocardial injury, cardiac ultrasound is employed to evaluate the myocardial systolic function, and Evans-Blue/triphenyl tetrazolium chloride staining is used to measure infarct size. In general, this protocol reduces procedure duration, ensures controllable infarct size, and improves mouse survival.

Here we describe a simple and reproducible method that can induce myocardial infarction or myocardial ischemia-reperfusion injury in mice by precision ligation of the left anterior descending coronary artery through micromanipulation.

Induzione di infarto miocardico e danno da ischemia-riperfusione miocardica nei topi

Acute myocardial infarction is a common cardiovascular disease with high mortality. Myocardial reperfusion injury can counteract the beneficial effects of ...

High-Resolution Cardiac Positron Emission Tomography/Computed Tomography for Small Animals

Positron emission tomography (PET) and computed tomography (CT) are among the most employed diagnostic imaging techniques, and both serve in understanding cardiac function and metabolism. In preclinical research, dedicated scanners with high sensitivity and high spatio-temporal resolution are employed, designed to cope with the demanding technological requirements posed by the small heart size and very high heart rates of mice and rats. In this paper, a bimodal cardiac PET/CT imaging protocol for experimental mouse and/or rat models of cardiac diseases is described, from animal preparation and image acquisition and reconstruction to image processing and visualization.
In particular, the 18F-labeled fluorodeoxyglucose ([18F]FDG)-PET scan allows for the measurement and visualization of glucose metabolism in the different segments of the left ventricle (LV). Polar maps are convenient tools to display this information. The CT part consists of a time-resolved 3D reconstruction of the entire heart (4D-CT) using retrospective gating without electrocardiography (ECG) leads, allowing the morphofunctional evaluation of the LV and the subsequent quantification of the most important cardiac function parameters, such as ejection fraction (EF) and stroke volume (SV). Using an integrated PET/CT scanner, this protocol can be executed within the same anesthesia induction without the need to reposition the animal between different scanners. Hence, PET/CT can be seen as a comprehensive tool for the morphofunctional and metabolic evaluation of the heart in several small animal models of cardiac diseases.

Here, we present an experimental imaging protocol for the quantification of cardiac function and morphology using high-resolution positron emission tomography/computed tomography for small animals. Both mice and rats are considered, discussing the different requirements of computed tomography contrast agents for the two species.

Tomografia cardiaca ad emissione di positroni ad alta risoluzione/tomografia computerizzata per piccoli animali

Positron emission tomography (PET) and computed tomography (CT) are among the most employed diagnostic imaging techniques, and both serve in understanding ...

An Experimental Model of Myocardial Infarction for Studying Cardiac Repair and Remodeling in Knockout Mice

Cardiovascular disease is the most prevalent cause of death in Western countries, with acute myocardial infarction (MI) being the most prevalent form. This paper describes a protocol for studying the role of galectin 3 (Gal-3) in the temporal evolution of cardiac healing and remodeling in an experimental animal model of MI. 
The procedures described include an experimental model of MI with a permanent coronary ligature in male C57BL/6J (control) and Gal-3 knockout (KO) mice, an echocardiography procedure to study cardiac remodeling and systolic function in vivo, a histological evaluation of interstitial myocardial fibrosis with picrosirius red-stained and rhodamine-conjugated lectin-stained sections for studying myocyte hypertrophy by the cross-sectional area (MCSA), and the quantification of infarct size and cardiac remodeling (scar thinning, septum thickness, and expansion index) by planimetry in slices stained with Masson's trichrome and triphenyl tetrazolium chloride. Gal-3 KO mice with MI showed disrupted cardiac remodeling and an increase in the scar thinning ratio and the expansion index. At the onset of MI, myocardial function and cardiac remodeling were also severely affected. At 4 weeks post MI, the natural evolution of fibrosis in infarcted Gal-3 KO mice was also affected. 
In summary, the experimental model of MI is a suitable model for studying the temporal evolution of cardiac repair and remodeling in mice with the genetic deletion of Gal-3 and other animal models. The lack of Gal-3 affects the dynamics of cardiac repair and disrupts the evolution of cardiac remodeling and function after MI.

Here, we describe an experimental model of myocardial infarction, an echocardiography procedure to study cardiac remodeling and function, and procedures for quantifying fibrosis and hypertrophy in picrosirius red-stained and rhodamine-stained sections, as well as the infarct size and expansion index in slices stained with Masson's trichrome.

Cardiovascular disease is the most prevalent cause of death in Western countries, with acute myocardial infarction (MI) being the most prevalent form. ...