Somos gratos pelos recursos fornecidos pela Harvard Medical School/Brigham e pelo Women's Hospital Cardiovascular Physiology Core Laboratory Laboratory. Este trabalho foi apoiado em parte por financiamento dos Institutos Nacionais de Saúde HL088533, HL071775, HL093148 e HL099073 (RL). MB recebeu um prêmio de pós-doutorado da American Heart Association. Ku é um beneficiário de um prêmio de bolsa de pós-doutorado da American Heart Association. SC foi apoiado por um prêmio da Fundação Ellison.

1. Elaboração de Imagens para Análises
<ol><li>Obtenha imagens do modo B ecocardiográficos murinos ou humanos na visão de longo eixo parasténal. Ajuste as configurações de compensação de ganho de tempo e a colocação do foco de transmissão para otimizar a visualização da LV e outras estruturas cardíacas na visão parasternal, por prática usual. Certifique-se de que todas as imagens sejam salvas em formato de arquivo DICOM. As visualizações padronizadas da imagem colocam a parede ventricular esquerda inferolateral na base do quadro. Os quadros devem exibir a totalidade do miocárdio ventricular esquerdo e pericárdio. A resolução deve ser alta o suficiente para demarcar a fronteira pericárdia, a parede do miocárdio e a borda endocardial do ventrículo esquerdo. Descarte imagens com excesso de abandono ou artefatos de imagem.</li>
	<li>Importe um arquivo de imagem para análise na plataforma de software ImageJ v1.46 como um arquivo DICOM. Converta o arquivo em um arquivo de imagem de 8 bits.</li>
	<li>Role por quadros consecutivos do ciclo cardíaco até atingir um quadro de qualidade adequada. Alternativamente, selecione o quadro de dia diastólica final em um programa de visualização ecocardiográfica e, em seguida, exporte para um formato de arquivo .jpg de alta resolução para uso no ImageJ. Identifique os quadros mais próximos da estatóstola final usando a onda R do rastreamento ECG e, em seguida, identifique o único melhor quadro que captura o LV com dimensão interna máxima. Considere este quadro único o quadro de dia diastólica final.</li>
	<li>Sugere-se que os usuários fiquem cegos à identidade do sujeito ao selecionar regiões de interesse.</li>
</ol>2. Amostragem de ROI
<ol><li>Seleção de referência pericárdio. Ao selecionar a região pericárvia de interesse (ROI), procure capturar a heterogeneidade do tecido pericárdico. Observe que o brilho e o contraste da imagem podem ser ajustados para a seleção do ROI, conforme necessário, sem qualquer efeito sobre os resultados da análise.<ol>
<li>Usando a ferramenta de desenho retângulo do ImageJ, selecione um retângulo com comprimento aproximando o terço médio da parede pericárdia inferolateral basal.</li>
		<li>Redimensione o ROI retangular para estender a largura do pericárdio usando a ferramenta de dimensionamento do ROI.</li>
		<li>Gire o ROI para ficar dentro da região pericárvia usando a ferramenta rotativa do ImageJ.</li>
		<li>Faça os ajustes necessários nos cantos do ROI pericárdica. Capture uma região pericárdia final de interesse que fica dentro do terço médio da parede pericárdia, e inclui a largura da parede pericárdia sem estender-se para as regiões miocáridas ou extra-cardíacas. Objetivo de capturar a mesma localização relativa e percentual da área pericárvia total para todas as medidas feitas em um determinado estudo.</li>
		<li>Aplique o algoritmo à seleção através de ferramentas de análise ImageJ (ver seção 3).</li>
	</ol>
</li>
	<li>Seleção do miocárdio. Mais uma vez, procure capturar a heterogeneidade do tecido miocárdio dentro do terço médio da parede do miocárdio basal inferolateral. Observe que o brilho e o contraste da imagem podem ser ajustados para a seleção do ROI, conforme necessário, sem qualquer efeito sobre os resultados da análise.<ol>
<li>Selecione um retângulo que abrange a largura da parede do miocárdio, excluindo o endoárdio e o epicárdio. Certifique-se de que a seleção do miocárdio está adjacente à seleção pericárvia e no mesmo ângulo. Não inclua áreas de músculo papilar dentro da área de seleção.</li>
		<li>Gire o ROI miocárdico de tal forma que ele esteja paralelo à seleção pericárvia.</li>
		<li>Faça os ajustes necessários nos cantos do ROI miocárdio. Isole uma região final do miocárdio de interesse que fica dentro do terço médio da parede do miocárdio, e captura a largura da parede sem se estender para as regiões pericáridas ou intraluminais.</li>
		<li>Aplique o algoritmo à seleção através de uma macro ImageJ.</li>
	</ol>
</li>
</ol>3. Análise e Processamento de Dados
<ol><li>Instale a macro ImageJ chamada "getHistogramValues.txt".</li>
	<li>Use a ferramenta de análise histograma ImageJ para visualizar a distribuição dos valores de intensidade do sinal dentro do ROI (realize esta etapa para a seleção pericárvia e para a seleção do miocárdio).</li>
	<li>Use a macro ImageJ para registrar esses valores de densidade de sinal para o ROI (realize esta etapa para a seleção pericárcial e para a seleção do miocárdio).<ol>
<li>Atribua um valor de intensidade de 0 (mais escuro) a 255 (mais brilhantes) unidades a cada pixel dentro da seleção.</li>
		<li>Organizar os valores de intensidade hierarquicamente, em ordem de aumento de intensidade, para produzir uma distribuição da intensidade do sinal.</li>
		<li>Selecione e reporte os seguintes valores percentil para a distribuição: percentil 20, percentil de 50º (mediano) e 80percentil.</li>
	</ol>
</li>
	<li>Normalize as intensidades do miocárdio usando a referência pericárvia.<ol>
<li>Normalizar dividindo os valores percentil de intensidade do miocárdio pelos valores percentil pericárdico correspondentes de intensidade12, ou subtraindo o valor percentil do miocárdio de intensidade do valor percentil pericárdico da intensidade13.</li>
		<li>Valores do relatório para os quatro métodos analíticos: valores normalizados do miocárdio para pericárdio para os valores de 20percentil, percentil de 50º percentil (mediano) e 80º percentil.</li>
	</ol>
</li>
</ol>4. Quantificando a Variabilidade Cíclica
<ol><li>Aplique algoritmo às seleções do miocárdio através de quadros consecutivos do arquivo DICOM, movendo-se através do ciclo cardíaco. Compare diferenças nas distribuições de intensidade entre os quadros, com atenção aos quadros sistólicos e terminais. Todas as análises de imagem descritas acima são realizadas offline em imagens ecocardiográficas não invasivas previamente adquiridas e armazenadas digitalmente em formato DICOM. Todos os protocolos de estudo foram aprovados pelo conselho de revisão institucional da Brigham and Women's e pelo Comitê de Cuidados e Uso Institucional da Área Médica de Harvard.</li>
</ol>

<ol>
	<li>Yamada, S., Komuro, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrated+backscatter+for+the+assessment+of+myocardial+viability.">Integrated backscatter for the assessment of myocardial viability.</a> Curr. Opin. Cardiol. 21, 433-437 (2006).</li><li>Mimbs, J. W., O'Donnell, M., Bauwens, D., Miller, J. W., Sobel, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dependence+of+ultrasonic+attenuation+and+backscatter+on+collagen+content+in+dog+and+rabbit+hearts.">The dependence of ultrasonic attenuation and backscatter on collagen content in dog and rabbit hearts.</a> Circ. Res. 47, 49-58 (1980).</li><li>Picano, E., 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=In+vivo+quantitative+ultrasonic+evaluation+of+myocardial+fibrosis+in+humans.">In vivo quantitative ultrasonic evaluation of myocardial fibrosis in humans.</a> Circulation. 81, 58-64 (1990).</li><li>Mizuno, R., 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=Myocardial+ultrasonic+tissue+characterization+for+estimating+histological+abnormalities+in+hypertrophic+cardiomyopathy:+comparison+with+endomyocardial+biopsy+findings.">Myocardial ultrasonic tissue characterization for estimating histological abnormalities in hypertrophic cardiomyopathy: comparison with endomyocardial biopsy findings.</a> Cardiology. 96, 16-23 (2001).</li><li>Mizuno, R., Fujimoto, S., Saito, Y., Nakamura, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-invasive+quantitation+of+myocardial+fibrosis+using+combined+tissue+harmonic+imaging+and+integrated+backscatter+analysis+in+dilated+cardiomyopathy.">Non-invasive quantitation of myocardial fibrosis using combined tissue harmonic imaging and integrated backscatter analysis in dilated cardiomyopathy.</a> Cardiology. 108, 11-17 (2007).</li><li>Marini, C., 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=Cyclic+variation+in+myocardial+gray+level+as+a+marker+of+viability+in+man.+A+videodensitometric+study.">Cyclic variation in myocardial gray level as a marker of viability in man. A videodensitometric study.</a> Eur. Heart. J. 17, 472-479 (1996).</li><li>Komuro, K., 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=Sensitive+detection+of+myocardial+viability+in+chronic+coronary+artery+disease+by+ultrasonic+integrated+backscatter+analysis.">Sensitive detection of myocardial viability in chronic coronary artery disease by ultrasonic integrated backscatter analysis.</a> J. Am. Soc. Echocardiogr. 18, 26-31 (2005).</li><li>Ciulla, M., 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=Echocardiographic+patterns+of+myocardial+fibrosis+in+hypertensive+patients:+endomyocardial+biopsy+versus+ultrasonic+tissue+characterization.">Echocardiographic patterns of myocardial fibrosis in hypertensive patients: endomyocardial biopsy versus ultrasonic tissue characterization.</a> J. Am. Soc. Echocardiogr. 10, 657-664 (1997).</li><li>Maceira, A. M., Barba, J., Varo, N., Beloqui, O., Diez, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasonic+backscatter+and+serum+marker+of+cardiac+fibrosis+in+hypertensives.">Ultrasonic backscatter and serum marker of cardiac fibrosis in hypertensives.</a> Hypertension. 39, 923-928 (2002).</li><li>D'Hooge, J., 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=High+frame+rate+myocardial+integrated+backscatter.+Does+this+change+our+understanding+of+this+acoustic+parameter.">High frame rate myocardial integrated backscatter. Does this change our understanding of this acoustic parameter.</a> Eur. J. Echocardiogr. 1, 32-41 (2000).</li><li>Finch-Johnston, A. E., 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=Cyclic+variation+of+integrated+backscatter:+dependence+of+time+delay+on+the+echocardiographic+view+used+and+the+myocardial+segment+analyzed.">Cyclic variation of integrated backscatter: dependence of time delay on the echocardiographic view used and the myocardial segment analyzed.</a> J. Am. Soc. Echocardiogr. 13, 9-17 (2000).</li><li>Di Bello, V., 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=Increased+echodensity+of+myocardial+wall+in+the+diabetic+heart:+an+ultrasound+tissue+characterization+study.">Increased echodensity of myocardial wall in the diabetic heart: an ultrasound tissue characterization study.</a> J. Am. Coll. Cardiol. 25, 1408-1415 (1995).</li><li>Takiuchi, 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=Quantitative+ultrasonic+tissue+characterization+can+identify+high-risk+atherosclerotic+alteration+in+human+carotid+arteries.">Quantitative ultrasonic tissue characterization can identify high-risk atherosclerotic alteration in human carotid arteries.</a> Circulation. 102, 766-770 (2000).</li><li>Querejeta, R., 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=Serum+carboxy-terminal+propeptide+of+procollagen+type+I+is+a+marker+of+myocardial+fibrosis+in+hypertensive+heart+disease.">Serum carboxy-terminal propeptide of procollagen type I is a marker of myocardial fibrosis in hypertensive heart disease.</a> Circulation. 101, 1729-1735 (2000).</li></ol>

Nenhum conflito de interesses declarado.

Descrevemos o protocolo para um algoritmo de análise de imagem que quantifica a distribuição da intensidade do sinal sonográfico e, por sua vez, oferece uma medida substituta da microestrutura miocárdia. As características padronizadas do protocolo, incluindo seleção, dimensionamento e posicionamento do ROI e região de referência, servem para minimizar a variabilidade do usuário e do assunto. Demonstramos que quando aplicado a imagens ecocardiográficas de um quadro único de fim, o algoritmo pode distinguir a...

A ecocardiografia é uma modalidade de imagem amplamente acessível que é comumente usada para caracterizar e quantificar alterações na estrutura e função cardíaca. Avaliações ultrassônicas do tecido cardíaco podem incluir análises da intensidade do sinal de backscatter dentro de uma determinada região de interesse em um único ponto no tempo, bem como ao longo do ciclo cardíaco. Estudos anteriores sugerem que medidas de intensidade de sinal sonográfico podem identificar a presença subjacente da desordem da fibra miocárdia, tecido miocárdio viável versus inviável e fibrose interstícia1-3. Referimo-nos à "microestrutura" do miocárdio como a arquitetura tecidual que pode ser caracterizada, utilizando análise sonográfica, além de medições lineares de tamanho bruto e morfologia. Assim, foram utilizadas análises de intensidade de sinal sonográfico para avaliar alterações microestruturais do tecido miocárdio no cenário de cardiomiopatia hipertrófica e dilatada4,5, doença arterial coronariana crônica6,7e doença cardíaca hipertensiva8,9. No entanto, técnicas previamente estabelecidas têm se apoiado predominantemente no valor integrado ou médio das intensidades de sinal de backscatter, que podem ser suscetíveis à variabilidade do ruído aleatório5, dados aliased de baixas taxas dequadros 10, e atrasos de tempo para algoritmos baseados na variação cíclica11.
Aqui, descrevemos o método de usar um algoritmo de análise de imagem baseado em ultrassom que se estende a partir de métodos anteriores; este algoritmo se concentra em um único quadro de dia diastólica final para análise de imagem e explica a distribuição completa dos valores de intensidade de sinal derivados de uma determinada amostra do miocárdio. Usando o pericárdio como referência in-frame12,13,o algoritmo quantifica a variação nas distribuições de intensidade de sinal sonográfico e oferece uma medida de substituto aprimorada da microestrutura miocárdia. Em um protocolo passo a passo, descrevemos métodos para preparar imagens para uso, amostragem de regiões de interesse e processamento de dados dentro de regiões de interesse selecionadas. Também mostramos resultados representativos da aplicação do algoritmo a imagens ecocardiográficas adquiridas de camundongos e humanos com exposição variável ao estresse pós-carga no ventrículo esquerdo.

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">ImageJ v 1.46</td>
			<td style="width:268px;">NIH (Bethesda, MD)</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">open access software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Power ShowCase</td>
			<td style="width:268px;">Trillium Technology (Ann Arbor, MI)</td>
			<td style="width:119px;"></td>
			<td>commercial software</td>
		</tr>
	</tbody>
</table>

ultrasonic assessment of myocardial microstructure

A ecocardiografia é uma modalidade de imagem amplamente acessível que é comumente usada para caracterizar e quantificar alterações na estrutura e função cardíaca. Avaliações ultrassônicas do tecido cardíaco podem incluir análises da intensidade do sinal de backscatter dentro de uma determinada região de interesse. Técnicas previamente estabelecidas têm se apoiado predominantemente no valor integrado ou médio das intensidades de sinal de backscatter, que podem ser suscetíveis à variabilidade a partir de dados aliased de baixas taxas de quadros e atrasos de tempo para algoritmos baseados na variação cíclica. Aqui, descrevemos um algoritmo de imagem baseado em ultrassom que se estende a partir de métodos anteriores, pode ser aplicado a um único quadro de imagem e explica a distribuição completa dos valores de intensidade de sinal derivados de uma dada amostra de miocárdio. Quando aplicado a dados representativos de camundongos e imagens humanas, o algoritmo distingue entre sujeitos com e sem exposição à resistência crônica pós-carga. O algoritmo oferece uma medida de substituto aprimorada da microestrutura miocárdio e pode ser realizado usando software de análise de imagem de acesso aberto.

A análise da intensidade do sinal é realizada em 4 etapas principais(Figura 1), incluindo: 1) seleção e formatação de imagens, 2) roi amostral e áreas de referência, aplicação de algoritmos 3 e 4) processamento de valores finais para produzir relações de intensidade miocárdio-pericárcial. A seleção e o tamanho do ROI são padronizados para limitar o interusário, bem como a variabilidade intrausuária(Figura 2). O posicionamento de cada ROI também é padronizado em rela?...

Watch this Scientific Journal Video about Ultrasonic Assessment of Myocardial Microstructure at JoVE.com

Ultrasonic Assessment of Myocardial Microstructure

A ecocardiografia é comumente usada para caracterizar e quantificar alterações na estrutura e função cardíaca. Descrevemos um algoritmo de imagem baseado em ultrassom que oferece uma medida de substituto aprimorada da microestrutura do miocárdio e pode ser realizado usando software de análise de imagem de acesso aberto.

Avaliação ultrassônica da microestrutura miocárdio

Echocardiography is a widely accessible imaging modality that is commonly used to noninvasively characterize and quantify changes in cardiac structure and ...

ultrasonic-assessment-of-myocardial-microstructure

Research

JoVE Journal

Medicine

5.3K visualizações.  Harvard Medical School. A ecocardiografia é comumente usada para caracterizar e quantificar alterações na estrutura e função cardíaca. Descrevemos um algoritmo de imagem baseado em ultrassom que oferece uma medida de substituto aprimorada da microestrutura do miocárdio e pode ser realizado usando software de análise de imagem de acesso aberto.

Vídeo: Ultrasonic Assessment of Myocardial Microstructure

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.

Avaliação Strain Ressonância Magnética Derivado do Miocárdio Usando o controle de recursos

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 ...

Medicina

Acute Myocardial Infarction in Rats

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular diseases. Animal models that mimic human cardiac disease, such as myocardial infarction (MI) and ischemia-reperfusion (IR) that induces heart failure as well as pressure-overload (transverse aortic constriction) that induces cardiac hypertrophy and heart failure (Goldman and Tarnavski), are useful models to study cardiovascular disease. In particular, myocardial ischemia (MI) is a leading cause for cardiovascular morbidity and mortality despite controlling certain risk factors such as arteriosclerosis and treatments via surgical intervention (Thygesen). Furthermore, an acute loss of the myocardium following myocardial ischemia (MI) results in increased loading conditions that induces ventricular remodeling of the infarcted border zone and the remote non-infarcted myocardium. Myocyte apoptosis, necrosis and the resultant increased hemodynamic load activate multiple biochemical intracellular signaling that initiates LV dilatation, hypertrophy, ventricular shape distortion, and collagen scar formation. This pathological remodeling and failure to normalize the increased wall stresses results in progressive dilatation, recruitment of the border zone myocardium into the scar, and eventually deterioration in myocardial contractile function (i.e. heart failure). The progression of LV dysfunction and heart failure in rats is similar to that observed in patients who sustain a large myocardial infarction, survive and subsequently develops heart failure (Goldman). The acute myocardial infarction (AMI) model in rats has been used to mimic human cardiovascular disease; specifically used to study cardiac signaling mechanisms associated with heart failure as well as to assess the contribution of therapeutic strategies for the treatment of heart failure. The method described in this report is the rat model of acute myocardial infarction (AMI). This model is also referred to as an acute ischemic cardiomyopathy or ischemia followed by reperfusion (IR); which is induced by an acute 30-minute period of ischemia by ligation of the left anterior descending artery (LAD) followed by reperfusion of the tissue by releasing the LAD ligation (Vasilyev and McConnell). This protocol will focus on assessment of the infarct size and the area-at-risk (AAR) by Evan's blue dye and triphenyl tetrazolium chloride (TTC) following 4-hours of reperfusion; additional comments toward the evaluation of cardiac function and remodeling by modifying the duration of reperfusion, is also presented. Overall, this AMI rat animal model is useful for studying the consequence of a myocardial infarction on cardiac pathophysiological and physiological function.

The rat model of acute myocardial infarction (AMI) is useful to study the consequence of a MI on cardiac pathophysiological and physiological function.

Infarto Agudo do Miocárdio em Ratos

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular ...

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.

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.

Avaliação da função cardíaca e Morfologia do miocárdio Usando Pequenos Animais Inversion Recovery Olha-locker (SALLI) MRI em ratos

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

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.

Ressonância magnética e PET no rato modelos de Infarto do Miocárdio

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 ...

Myocardial Infarction and Functional Outcome Assessment in Pigs

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One important prerequisite is a good understanding of all safety and efficacy aspects obtained in a large animal model that validly reflect the human scenario of myocardial infarction (MI). Pigs are widely used in this regard since their cardiac size, hemodynamics, and coronary anatomy are close to that of humans. Here, we present an effective protocol for using the porcine MI model using a closed-chest coronary balloon occlusion of the left anterior descending artery (LAD), followed by reperfusion. This approach is based on 90 min of myocardial ischemia, inducing large left ventricle infarction of the anterior, septal and inferoseptal walls. Furthermore, we present protocols for various measures of outcome that provide a wide range of information on the heart, such as cardiac systolic and diastolic function, hemodynamics, coronary flow velocity, microvascular resistance, and infarct size. This protocol can be easily tailored to meet study specific requirements for the validation of novel cardioregenerative biologics at different stages (i.e. directly after the acute ischemic insult, in the subacute setting or even in the chronic MI once scar formation has been completed). This model therefore provides a useful translational tool to study MI, subsequent adverse remodeling, and the potential of novel cardioregenerative agents.

This protocol describes the porcine myocardial infarction (MI) model using a 90 min closed-chest coronary balloon occlusion of the left anterior descending artery (LAD), followed by reperfusion. Furthermore, the protocol for several outcome parameters, such as cardiac function, hemodynamics, microvascular resistance, and infarct size, are also presented.

Infarto do Miocárdio e Avaliação de Resultados Funcional em porcos

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One ...

Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction

Mortality after acute myocardial infarction remains substantial and is associated with significant morbidity, like heart failure. Novel therapeutics are therefore required to confine cardiac damage, promote survival and reduce the disease burden of heart failure. Large animal experiments are an essential part in the translational process from experimental to clinical therapies. To optimize clinical translation, robust and representative outcome measures are mandatory. The present manuscript aims to address this need by describing the assessment of three clinically relevant outcome modalities in a pig acute myocardial infarction (AMI) model: infarct size in relation to area at risk (IS/AAR) staining, 3-dimensional transesophageal echocardiography (TEE) and admittance-based pressure-volume (PV) loops. Infarct size is the main determinant driving the transition from AMI to heart failure and can be quantified by IS/AAR staining. Echocardiography is a reliable and robust tool in the assessment of global and regional cardiac function in clinical cardiology. Here, a method for three-dimensional transesophageal echocardiography (3D-TEE) in pigs is provided. Extensive insight into cardiac performance can be obtained by admittance-based pressure-volume (PV) loops, including intrinsic parameters of myocardial function that are pre- and afterload independent. Combined with a clinically feasible experimental study protocol, these outcome measures provide researchers with essential information to determine whether novel therapeutic strategies could yield promising targets for future testing in clinical studies.

Reliable and accurate outcome assessment is the key for translation of preclinical therapies into clinical treatment. The current paper describes how to assess three clinically relevant primary outcome parameters of cardiac performance and damage in a pig acute myocardial infarction model.

Avaliação do resultado principal em um modelo suíno de Infarto Agudo do Miocárdio

Mortality after acute myocardial infarction remains substantial and is associated with significant morbidity, like heart failure. Novel therapeutics are ...

Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation

The value of conventional echocardiography is limited by differences in inter-individual image interpretation and therefore largely dependent on the examiners&#39; expertise. Speckle tracking Echocardiography (STE) is a promising but technically challenging method that can be used to quantitatively assess regional and global systolic and diastolic myocardial performance. Myocardial strain and strain rate can be measured in all three dimensions&#160;&#8212; radial, circumferential, longitudinal &#8212; of myocardial deformation. Standard cross-sectional two-dimensional B-mode images are recorded and subsequently postprocessed by automated continuous frame-by-frame tracking and motion analysis of speckles within the myocardium. Images are recorded as digital loops and synchronized to a 3-lead EKG for timing purposes. Longitudinal deformation is assessed in the apical 4-, 3-, and 2-chamber views. Circumferential and radial deformation are measured in the parasternal short axis plane.
Optimal image quality and accurate tissue tracking are paramount for the correct determination of myocardial performance parameters. Utilizing transthoracic STE in a healthy volunteer, the present article is a detailed outline of the essential steps and potential pitfalls of quantitative echocardiographic myocardial deformation analysis.

Speckle tracking echocardiography is an emerging diagnostic imaging technique for the quantitative assessment of global and regional myocardial performance. Standard view echocardiographic motion images are recorded and deformation parameters are subsequently measured by automated continuous frame-by-frame tracking and motion analysis of speckles within the B-mode images of the myocardium.

Transtorácica salpico de rastreamento A ecocardiografia para a avaliação quantitativa do Ventrículo Esquerdo do miocárdio Deformação

The value of conventional echocardiography is limited by differences in inter-individual image interpretation and therefore largely dependent on the ...

Histological Quantification of Chronic Myocardial Infarct in Rats

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ischemic injury. Following the initial acute phase, chronic remodeling of the left ventricle (LV) modifies the structure and function of the heart. Permanent coronary ligation in small animals has been widely used as a reference model for a chronic model of MI. Thinning of the infarcted wall progressively develops to transmural fibrosis. Histological assessment of infarct size is commonly performed; nevertheless, a standardization of the methods for quantification is missing. Indeed, important methodological aspects, such as the number of sections analyzed and the sampling and quantification methods, are usually not described and therefore preclude comparison across investigations. Too often, quantification is performed on a single section obtained at the level of the papillary muscles. Because novel strategies aimed at reducing infarct expansion and remodeling are under investigation, there is an important need for the standardization of accurate heart sampling protocols. We describe an accurate method to quantify the infarct size using a systematic sampling of harvested rat heart and image analyses of trichromatic stained histological sections obtained from base to apex. We also provide evidence that calculating the expansion index (EI) allowed for infarct size assessment, taking into account changes of the left ventricle throughout the remodeling.

The post-mortem assessment of myocardial infarction (MI) in rodents is based on quantification of the infarct on stained heart sections. We describe an accurate method to quantify the infarct size using systematic sampling of harvested rat hearts from base to apex and image analyses of trichrome-stained histological sections.

Quantificação histológico de miocárdio crônico infarto em ratos

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ...

3D Whole-heart Myocardial Tissue Analysis

Cardiac regenerative therapies aim to protect and repair the injured heart in patients with ischemic heart disease. By injecting stem cells or other biologicals that enhance angio- or vasculogenesis into the infarct border zone (IBZ), tissue perfusion is improved, and the myocardium can be protected from further damage. For maximum therapeutic effect, it is hypothesized that the regenerative substance is best delivered to the IBZ. This requires accurate injections and has led to the development of new injection techniques. To validate these new techniques, we have designed a validation protocol based on myocardial tissue analysis. This protocol includes whole-heart myocardial tissue processing that enables detailed two-dimensional (2D) and three-dimensional (3D) analysis of the cardiac anatomy and intramyocardial injections. In a pig, myocardial infarction was created by a 90-min occlusion of the left anterior descending coronary artery. Four weeks later, a mixture of a hydrogel with superparamagnetic iron oxide particles (SPIOs) and fluorescent beads was injected in the IBZ using a minimally-invasive endocardial approach. 1 h after the injection procedure, the pig was euthanized, and the heart was excised and embedded in agarose (agar). After the solidification of the agar, magnetic resonance imaging (MRI), slicing of the heart, and fluorescence imaging were performed. After image post-processing, 3D analysis was performed to assess the IBZ targeting accuracy. This protocol provides a structured and reproducible method for the assessment of the targeting accuracy of intramyocardial injections into the IBZ. The protocol can be easily used when the processing of scar tissue and/or validation of the injection accuracy of the whole heart is desired.

This protocol describes a novel method for the 3D comparison of whole-heart myocardial tissue with MRI. This is designed for the accurate assessment of intramyocardial injections in the infarct border zone of a chronic porcine model of myocardial infarction.

Análise Tecidos do Miocárdio Whole-coração 3D

Cardiac regenerative therapies aim to protect and repair the injured heart in patients with ischemic heart disease. By injecting stem cells or other ...

Ultrasonic-augmented Primary Adult Fibroblast Isolation

Primary adult fibroblasts have become an important tool to study fibrosis, fibroblast interactions and inflammation in all body tissues. Since primary fibroblasts cannot divide indefinitely due to myofibroblast differentiation or senescence induction, new cultures must be established regularly. However, there are several obstacles to overcome during the processes of developing a reliable isolation protocol and primary fibroblast isolation itself: the method&#8217;s degree of difficulty (especially for beginners), the risk of bacterial contamination, the required time until primary fibroblasts can be used for experiments, and subsequent cell quality and viability. In this study, a fast, reliable and easy-to-learn protocol to isolate and culture primary adult fibroblasts from mouse heart, lung, liver and kidney combining enzymatic digestion and ultrasonic agitation is provided.

We present a protocol to isolate primary adult fibroblasts in an easy, fast and reliable way, performable by beginners (e.g., students). The procedure combines enzymatic tissue digestion and mechanical agitation with ultrasonic waves to obtain primary fibroblasts. The protocol can easily be adapted to specific experimental requirements (e.g., human tissue).

Isolação adulta preliminar ultra-som-aumentada do fibroblasto

Primary adult fibroblasts have become an important tool to study fibrosis, fibroblast interactions and inflammation in all body tissues. Since primary ...