Characterization of Cardiac Dynamics in an Acute Myocardial Infarction Model by Four-Dimensional Optoacoustic and Magnetic Resonance Imaging.
Characterization of Cardiac Dynamics in an Acute Myocardial Infarction Model by Four-Dimensional Optoacoustic and Magnetic Resonance Imaging.
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通过四维光声成像和磁共振成像对急性心肌梗死模型中心脏动力学的特征描述
DOI：
10.7150/thno.20616
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发表时间：
2017
期刊：
影响因子：
12.4
通讯作者：
Razansky D
中科院分区：
文献类型：
--
作者：
Lin HA;Déan-Ben XL;Ivankovic I;Kimm MA;Kosanke K;Haas H;Meier R;Lohöfer F;Wildgruber M;Razansky D
由于三维时间分辨率不足，现有的成像方式限制了在逐搏基础上提取小鼠心脏功能参数。更快的体积成像方法，使在体内表征的功能参数，准备推进心血管研究，并提供了一个更好的了解心脏疾病的机制。我们提出了一种新的方法，基于分析对比度增强的光声（OA）图像采集在高体积帧速率，而不使用心脏门控或其他方法进行运动校正。我们应用一个急性小鼠心肌梗死模型，优化采集无伪影的光声成像数据，研究心血管血流动力学。基于显著更高的肺通过时间（PTT），可以清楚地将心脏起搏（n = 21）与健康对照（n = 9）区分开来。（2.25 [2.00 - 2.41] s vs 1.34 [1.25 - 1.67] s，p = 0.0235），而心率无统计学显著差异（318 [252 - 361] bpm vs 264 [252 - 320] bpm，p = 0.3129）。然而，非线性心跳动力学在健康心脏中更强，如心跳频谱中的第三谐波分量所证明的。从相同小鼠获得的MRI数据进一步揭示了PTT随着梗塞的大小而增加，并且类似地随着射血分数的降低而增加。此外，发现梗死PTT与术后时间之间呈负相关，这表明心脏愈合的发生。结合经证实的光声追踪受损心肌内靶向探针的能力，我们的方法可以描绘心脏解剖结构、功能和分子特征，具有高空间和时间分辨率。具有最高时间分辨率的心脏动力学的体积四维光声表征可以在心肌缺血的小鼠模型中逐搏地捕获心血管动力学。
Extraction of murine cardiac functional parameters on a beat-by-beat basis is limited with the existing imaging modalities due to insufficient three-dimensional temporal resolution. Faster volumetric imaging methods enabling in vivo characterization of functional parameters are poised to advance cardiovascular research and provide a better understanding of the mechanisms underlying cardiac diseases. We present a new approach based on analyzing contrast-enhanced optoacoustic (OA) images acquired at high volumetric frame rate without using cardiac gating or other approaches for motion correction. We apply an acute murine myocardial infarction model optimized for acquisition of artifact-free optoacoustic imaging data to study cardiovascular hemodynamics. Infarcted hearts (n = 21) could be clearly differentiated from healthy controls (n = 9) based on a significantly higher pulmonary transit time (PTT) (2.25 [2.00-2.41] s versus 1.34 [1.25-1.67] s, p = 0.0235), while no statistically significant difference was observed in the heart rate (318 [252-361] bpm versus 264 [252-320] bpm, p = 0.3129). Nevertheless, nonlinear heartbeat dynamics was stronger in the healthy hearts, as evidenced by the third harmonic component in the heartbeat spectra. MRI data acquired from the same mice further revealed that the PTT increases with the size of infarction and similarly increases with reduced ejection fraction. Moreover, an inverse relationship between infarct PTT and time post-surgery was found, which suggests the occurrence of cardiac healing. In combination with the proven ability of optoacoustics to track targeted probes within the injured myocardium, our method can depict cardiac anatomy, function, and molecular signatures, with both high spatial and temporal resolution. Volumetric four-dimensional optoacoustic characterization of cardiac dynamics with supreme temporal resolution can capture cardiovascular dynamics on a beat-by-beat basis in mouse models of myocardial ischemia.