1. Preparation
1.1. Anesthesia of the rats
<ol>
	<li>Place the rat into a chamber prefilled with isoflurane (depending on the size of the chamber about 3 minutes of 5%) to anesthetize the rat.</li>
	<li>Once anesthetized, remove the rat and weigh it.</li>
	<li>Place the nose of the rat into the anesthesia mask (isoflurane 2-3% in oxygen 1 L/min) to maintain anesthesia. During anesthesia with isoflurane, the heart rates of rats decrease to 300-340 bpm (380-420 bpm in mice).</li>
</ol>
<p class="...

<ol>
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Here we present a method to generate multi-modality (cine MR, inversion-recovery and T1 maps) MR images in small animals. Small animal research plays an increasingly important role in cardiovascular disease research, and CMR is a powerful tool allowing us to study the function, structure and tissue composition of the myocardium. However, small animal CMR has a number of unique challenges owing to the high heart rates and small heart size. Improved methods of imaging, including more time efficient methods will play a furt...

Myocarditis is a major cause of acute heart failure, sudden death, and chronic dilated cardiomyopathy 7. CMR has been established as the gold standard technique for measurement of function and for in vivo tissue analysis. Novel imaging techniques and improvements in imaging could not only improve the diagnosis of myocarditis, but also aid the study of the pathophysiology and speed identification of therapeutic targets 8-10. Small animal imaging is an important tool for the study of cardiovascular diseases. Techniques routinely used in clinical CMR, such as late gadolinium enhancement (LGE) cannot easily be transferred to small animal CMR due to the animals' high heart rates; but could already be shown 11. The small animal Look-Locker inversion recovery (SALLI) approach generates multi-modal image data sets allowing for the comprehensive assessment of both cardiac function and morphology (Figures 1 and 3). Here we show, in detail, the procedure and setup for small animal imaging with a typical SALLI protocol. In particular we show the reconstruction and analysis of the T1 imaging data sets.

<table border="1">
		<tbody>
		 <tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		 </tr>
		 <tr>
			<td>Adhesive Tape (Silkafix)</td>
			<td>Lohmann und Rauscher</td>
			<td>34327</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Gadopentetat-Dimeglumin (Magnevist)</td>
			<td>Bayer</td>
			<td>G-00012163</td>
			<td>2mmol/Kg</td>
		 </tr>
		 <tr>
			<td>Introcan Safety-W (G24)</td>
			<td>B. Braun</td>
			<td>4254503-01</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Red Dot, Neonatal Monitoring Electrode with Pre-Attached Lead Wire</td>
			<td>3M</td>
			<td>2269T</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Skin glue (Histoacryl)</td>
			<td>B. Braun</td>
			<td>1050052</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Scales (Typ 440)</td>
			<td>Kern</td>
			<td>95088</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Skin desinfection (Softasept N)</td>
			<td>B. Braun Petzold</td>
			<td>360250</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Thermometer </td>
			<td>LumaSense Technologies</td>
			<td>Luxtron 812</td>
			<td></td>
		 </tr>
		</tbody>
 </table>

assessment of cardiac function and myocardial morphology using small animal look-locker inversion recovery (salli) mri in rats

Small animal magnetic resonance imaging is an important tool to study cardiac function and changes in myocardial tissue. The high heart rates of small animals (200 to 600 beats/min) have previously limited the role of CMR imaging. Small animal Look-Locker inversion recovery (SALLI) is a T1 mapping sequence for small animals to overcome this problem 1. T1 maps provide quantitative information about tissue alterations and contrast agent kinetics. It is also possible to detect diffuse myocardial processes such as interstitial fibrosis or edema 1-6. Furthermore, from a single set of image data, it is possible to examine heart function and myocardial scarring by generating cine and inversion recovery-prepared late gadolinium enhancement-type MR images 1.
	The presented video shows step-by-step the procedures to perform small animal CMR imaging. Here it is presented with a healthy Sprague-Dawley rat, however naturally it can be extended to different cardiac small animal models.

Here we demonstrate the findings from a healthy Sprague Dawley Rat. With a well-prepared animal setup we described before, it is possible to get a stable ECG signal. Similar to human cardiac MRI protocols, we start with a survey to locate the heart. If the position of the rat in the coil is correct, we continue with a two-chamber view and a four-chamber view to detect the geometry for the SALLI stack.
The SALLI technique produces three types of images acquired at the same time. These are, firs...

Watch this Scientific Journal Video about Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats at JoVE.com

Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats

Contrast enhanced cardiac magnetic resonance (CMR) imaging allows comprehensive in vivo assessment of the heart in small animal models of cardiovascular disease. Here we detail the procedures to perform CMR imaging, reconstruction and analysis using Small Animal Lock-Locker Inversion Recovery (SALLI) in rats.

Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery (SALLI) MRI in Rats

Small animal magnetic resonance  imaging is an important tool to study cardiac function and changes in myocardial  tissue. The high heart rates of small ...

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Research

JoVE Journal

Medicine

12.6K visualizações.  German Heart Institute Berlin. A ressonância magnética cardíaca maior contraste (CMR) permite abrangente In vivo Avaliação do coração em pequenos modelos animais de doença cardiovascular. Aqui detalhamos os procedimentos para realizar CMR imagem, reconstrução e análise usando Pequenos Animais Inversion Recovery Lock-Locker (SALLI) em ratos.