ハーバード大学医学部/ブリガム・アンド・ウィメンズ病院心臓血管生理学コアラボラトリーのリソースに感謝しています。この研究は、国立衛生研究所の助成金HL088533、HL071775、HL093148、HL099073(RL)からの資金提供によって部分的に支援されました。MBは、米国心臓協会の創設者アフィリエイトポストドクターフェローシップ賞を受賞しました。KUは、米国心臓協会の創設者アフィリエイトポスドクフェローシップ賞を受賞しています。SCはエリソン財団の賞によって支えられました。

1. 分析のための画像の作成
<ol><li>寄星長軸図でマウスまたはヒト心エコーBモード画像を取得します。時間利得補正の設定と送信フォーカスの配置を調整して、通常の練習に従って、パラスターナルビューにおけるLVおよび他の心臓構造の可視化を最適化します。すべてのイメージが DICOM ファイル形式で保存されていることを確認します。標準化された画像ビューは、フレームの底部に下側左心室壁を配置します。フレームは左心室心筋および心膜の全体を表示しなければならない。解像度は、心膜の境界、心筋壁、および左心室の心筋境界を区切るのに十分な高さでなければなりません。余分なドロップアウトまたはイメージアーティファクトを含むイメージを破棄します。</li>
	<li>DICOMファイルとしてImageJソフトウェアプラットフォームv1.46に分析用の画像ファイルをインポートします。ファイルを 8 ビットイメージファイルに変換します。</li>
	<li>適切な品質のエンド拡張期フレームに達するまで、心臓サイクルの連続したフレームをスクロールします。または、心エコー表示プログラムでエンド拡張期フレームを選択し、ImageJ で使用するために高解像度.jpgファイル形式にエクスポートします。ECGトレースのR波を使用してエンド・ダイストールに最も近いフレームを特定し、最大内部次元でLVをキャプチャする単一の最良のフレームを特定します。この単一フレームをエンド拡張フレームと考えてください。</li>
	<li>関心のある地域を選択する際に、ユーザーがサブジェクト ID に目をつぶることをお勧めします。</li>
</ol>2. ROI サンプリング
<ol><li>心膜参照選択。関心のある心膜領域(ROI)を選択する際には、心膜組織の異質性を捉えることを目指す。画像の明るさとコントラストは、必要に応じて、解析結果に影響を与えることなく、ROIの選択に合わせて調整できます。<ol>
<li>ImageJ の矩形描画ツールを使用して、基底の内膜壁の 3 分の 1 に近い長さの長方形を選択します。</li>
		<li>ROI サイズ変更ツールを使用して、四角形の ROI を心膜の幅に合わせてサイズ変更します。</li>
		<li>ImageJ の回転ツールを使用して、心膜領域内に配置する ROI を回転させます。</li>
		<li>心膜 ROI のコーナーに必要な調整を行います。心膜壁の中央3分の1以内にあり、心筋領域または心外領域に伸びることなく心膜壁の幅を含む、関心のある最終的な心膜領域をキャプチャします。特定の研究で行われたすべての測定に対して、同じ相対位置と総心膜領域の割合をキャプチャすることを目指します。</li>
		<li>ImageJ 解析ツールを使用して選択にアルゴリズムを適用します(セクション3を参照)。</li>
	</ol>
</li>
	<li>心筋選択。もう一度、基底下心筋心筋壁の中央3分の1以内の心筋組織の不均一性を捕捉することを目指す。画像の明るさとコントラストは、必要に応じて、解析結果に影響を与えることなく、ROIの選択に合わせて調整できます。<ol>
<li>心内膜と心外膜を除いて、心筋壁の幅に及ぶ長方形を選択します。心筋選択が心膜選択に隣接し、同じθ角度にあることを確認してください。選択領域内に乳頭筋の領域を含めないでください。</li>
		<li>心筋ROIを心膜選択と平行になるように回転させます。</li>
		<li>心筋ROIのコーナーに必要な調整を行います。心筋壁の中央3分の1以内にある最終心筋領域を隔離し、心膜領域または内反領域に伸びることなく壁の幅を捉えます。</li>
		<li>アルゴリズムを ImageJ マクロを使用して選択に適用します。</li>
	</ol>
</li>
</ol>3. データ分析と処理
<ol><li>"取得のヒストグラム値.txt"と呼ばれる ImageJ マクロをインストールします。</li>
	<li>ImageJ ヒストグラム解析ツールを使用して、ROI 内の信号強度値の分布をプレビューします (心膜選択と心筋選択に対してこの手順を実行します)。</li>
	<li>ImageJ マクロを使用して、ROI のこれらの信号密度値を記録します (心膜選択と心筋選択に対してこのステップを実行します)。<ol>
<li>選択範囲内の各ピクセルに 0 (最も暗い) から 255 (最も明るい) 単位の強度値を割り当てます。</li>
		<li>強度値を階層的に並べ、強度を上げる順に、信号強度の分布を生成する。</li>
		<li>分布の百分位数の値として、20番目 の百分位数、50番目の 百分位数 (中央値)、および 80 パーセンタイルを選択してレポートします 。</li>
	</ol>
</li>
	<li>心膜参照を使用して心筋強度を正規化します。<ol>
<li>強度の心筋百分位数を、対応する心膜百分位値の強度12で割ることによって、または強度の心膜百分位値から強度の心筋百分位数値を差し引くことによって正規化する。</li>
		<li>4 つの分析方法のレポート値: 20パー センタイルの正規化された心筋対心筋値、50番目の 百分位数 (中央値)、および 80パー センタイル値。</li>
	</ol>
</li>
</ol>4. 周期的変動性の定量化
<ol><li>DICOMファイルの連続したフレームを介して心筋選択にアルゴリズムを適用し、心臓周期を移動する。フレーム間の強度分布の差を比較し、エンドシストリックフレームとエンド拡張期フレームに注意します。 上記の画像解析はすべて、以前に取得した非侵襲的な心エコー画像上でオフラインで行われ、DICOM形式でデジタル保存されます。すべての研究議定書は,ブリガム・アンド・ウィメンズ制度審査委員会とハーバード医療地域常設動物のケア・使用委員会によって承認されました。</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>

利益相反は宣言されていません。

我々は、ソノグラフィ信号強度分布を定量化し、ひいては心筋微細構造の代理尺度を提供する画像解析アルゴリズムのプロトコルを記述する。ROIと参照領域の選択、サイジング、位置決めなど、プロトコルの標準化された機能は、ユーザおよびサブジェクトベースの変動を最小限に抑えるのに役立ちます。我々は、エンド拡張期単一フレーム心エコー画像に適用すると、アルゴリズムが通常?...

心エコー検査は、心臓の構造および機能の変化を非侵襲的に特徴付け、定量化するために一般的に使用される広くアクセス可能な画像化モダリティである。心臓組織の超音波評価には、特定の時間内の特定の領域内の後方散乱信号強度の分析を含めることができ、また、心周期の過程で同様に。以前の研究では、ソノマの信号強度の尺度は、心筋線維の崩壊、生存可能対非生存性心筋組織、および間質線維症1-3の基礎的存在を特定できることを示唆している。我々は、心筋の「微細構造」を、総サイズおよび形態の線形測定を超えて、ソノグラフ解析を用いて特徴付けることができる組織アーキテクチャと呼ぶ。従って、ソノグラフィシグナル強度の解析は、肥大性および拡張型心筋症4,5、慢性冠動脈疾患6,7、および高血圧性心疾患8,9の設定における心筋組織の微細構造変化を評価するために用いられている。しかしながら、以前に確立された技術は、主に後方散乱信号強度の積分または平均値に依存しており、ランダムノイズ5、低フレームレート10からの別名データ、および周期変動11に基づくアルゴリズムの時間遅延による変動の影響を受けやすい可能性がある。
本明細書では、我々は、以前の方法から拡張超音波ベースの画像解析アルゴリズムを使用する方法を説明します。このアルゴリズムは、画像解析のための単一のエンド拡張フレームに焦点を当て、特定の心筋サンプルから導き出された信号強度値の完全分布を説明します。このアルゴリズムは、フレーム内基準12,13として心膜を用いることで、ソノグラフィ信号強度分布の変動を再現的に定量化し、心筋微細構造の強化された代理尺度を提供する。詳細なプロトコルでは、使用する画像の準備、対象領域のサンプリング、および対象領域内のデータの処理を行う方法について説明します。また、左心室の後負荷ストレスに対する可変暴露を有するマウスおよびヒトから取得した心エコー画像にアルゴリズムを適用した代表的な結果を示す。

<table border="0" cellpadding="0" cellspacing="0" width="770">
	<colgroup>
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		<col />
		<col />
		<col />
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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

心エコー検査は、心臓の構造および機能の変化を非侵襲的に特徴付け、定量化するために一般的に使用される広くアクセス可能な画像化モダリティである。心臓組織の超音波評価には、関心のある特定の領域内の後方散乱信号強度の解析が含まれる。以前に確立された技術は、主に後方散乱信号強度の統合値または平均値に依存しており、周期変動に基づくアルゴリズムの低フレームレートおよび時間遅延からの別名データによる変動の影響を受けやすい可能性があります。本明細書において、我々は、以前の方法から及ぶ超音波ベースの画像化アルゴリズムを記述し、単一の画像フレームに適用することができ、与えられた心筋サンプルから導出される信号強度値の全分布を占める。代表的なマウスおよびヒトイメージングデータに適用すると、このアルゴリズムは、慢性の後負荷抵抗の有無に関する被写体を区別します。このアルゴリズムは、心筋微細構造の拡張された代理尺度を提供し、オープンアクセス画像解析ソフトウェアを使用して実行することができる。

信号強度解析は、4つの主要なステップ(図1)を含む:画像選択とフォーマット、2)サンプリングROIおよび基準領域、3)アルゴリズムアプリケーション、および4)心筋対心筋強度比を得るための最終的な値を処理する。ROIの選択とサイズは、ユーザー間とユーザー内変動を制限するために標準化されています(図2)。各ROIの位置づけは、各被験者の解剖学的構造に関しても標?...

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

Ultrasonic Assessment of Myocardial Microstructure

心エコー検査は、心臓の構造および機能の変化を非侵襲的に特徴付け、定量化するために一般的に使用される。心筋微細構造の強化された代理尺度を提供し、オープンアクセス画像解析ソフトウェアを用いて実行できる超音波ベースの画像アルゴリズムについて述べる。

心筋微細構造の超音波評価

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

5.4K ビュー.  Harvard Medical School. 心エコー検査は、心臓の構造および機能の変化を非侵襲的に特徴付け、定量化するために一般的に使用される。心筋微細構造の強化された代理尺度を提供し、オープンアクセス画像解析ソフトウェアを用いて実行できる超音波ベースの画像アルゴリズムについて述べる。

ビデオ: 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.

特徴追跡を用いた磁気共鳴が派生心筋ストレインの評価

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 ...

医学

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.

ラットにおける急性心筋梗塞

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.

小動物ルックロッカー反転回復（サリー）ラットにおけるMRIを用いた心機能と心筋形態の評価

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

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.

豚における心筋梗塞および機能的結果の評価

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.

急性心筋梗塞の豚モデルにおける主要アウトカム評価

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.

左心室心筋変形の定量的評価のための経胸壁スペックル追跡心エコー検査

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.

ラットにおける慢性心筋梗塞の組織学的定量

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.

3Dホール・ハート心筋組織の分析

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).

超音波増強原発性成人線維芽細胞分離

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

Semi-Minimal Invasive Method to Induce Myocardial Infarction in Rats and the Assessment of Cardiac Function by an Isolated Working Heart System

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily and highly reproducible MI induction procedure is required to obtain further insight and better understanding of the underlying pathological changes. This procedure can also be used to evaluate the effects or potency of new and promising treatments (as drugs or interventions) in acute MI, subsequent remodeling and heart failure (HF). After intubation and pre-operative preparation of the animal, an anesthetic protocol with isoflurane was performed, and the surgical procedure was conducted&#160;quickly. Using a minimally invasive approach, the left anterior descending artery (LAD) was located and occluded by a ligature. The occlusion can be performed acutely for subsequent reperfusion (ischemia/reperfusion injury). Alternatively, the vessel can be ligated permanently to investigate the development of chronic MI, remodeling or HF. Despite common pitfalls, the drop-out rates are minimal. Various treatments such as remote ischemic conditioning can be examined for their cardioprotective potential pre-, peri- and post-operatively. The post-operative recovery was quick as the anesthesia was precisely controlled and the duration of the operation was short. Post-operative analgesia was administered for three days. The minimally invasive procedure reduces the risk of infection and inflammation. Furthermore, it facilitates rapid recovery. The &#8220;working heart&#8221; measurements were performed ex vivo and enabled precise control of preload, afterload and flow. This procedure requires specific equipment and training for adequate performance. This manuscript provides a detailed step-by-step introduction for conducting these measurements.

This article presents an efficient method to perform myocardial ischemia and subsequent chronic reperfusion in rats using a minimally invasive approach. In addition, left ventricular hemodynamic function of rats is assessed by echocardiography and isolated working heart methods.&#160;

ラットの心筋梗塞を誘導する半最小侵襲法と、単離した働く心臓システムによる心機能の評価

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily ...