Shear Forces from Flow Are Responsible for a Distinct Statistical Signature of Adherent Microbubbles in Large Vessels
Shear Forces from Flow Are Responsible for a Distinct Statistical Signature of Adherent Microbubbles in Large Vessels
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DOI：
10.2310/7290.2013.00057
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发表时间：
2013-09
影响因子：
2.8
通讯作者：
Shiying Wang;F. W. Mauldin;A. Klibanov;J. Hossack
中科院分区：
文献类型：
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作者：
Shiying Wang;F. W. Mauldin;A. Klibanov;J. Hossack
大血管中基于实时超声的靶向分子成像有望通过在斑块形成之前识别动脉粥样硬化的早期标志物来早期检测和诊断中风风险。基于奇异光谱的靶向分子 (SiSTM) 成像是最近提出的一种方法，它利用统计维度的变化（通过归一化奇异光谱面积 (NSSA) 量化）来对受体-配体结合的粘附微泡进行成像。然而，造成这种独特统计特征的精确物理机制此前尚不清楚。在这项研究中，进行了体外流动模型实验，以阐明大血管环境中的物理机制。在没有流动的情况下，随着微泡浓度或脉冲长度的增加，没有观察到粘附微泡相对于组织的 NSSA 增加 (p > .23; n = 5)，但随着流速的增加 (p < .97) 观察到了。此外，还证明了 NSSA 和去相关之间的单调关系。这些发现证实了这样的假设：粘附微泡的统计特征源自由流动剪切力引起的帧与帧去相关。
Real-time ultrasound-based targeted molecular imaging in large blood vessels holds promise for early detection and diagnosis of stroke risk by identifying early markers for atherosclerosis prior to plaque formation. Singular spectrum-based targeted molecular (SiSTM) imaging is a recently proposed method that uses changes in statistical dimensionality—quantified by a normalized singular spectrum area (NSSA)—to image receptor-ligand–bound adherent microbubbles. However, the precise physical mechanism responsible for the distinct statistical signature was previously unknown. In this study, in vitro flow phantom experiments were performed to elucidate the physical mechanism in large blood vessel environments. In the absence of flow, an increase in the NSSA of adherent microbubbles with respect to tissue was not observed with increased microbubble concentration or pulse length (p > .23; n = 5) but was observed with increased flow rate (p .97). In addition, a monotonic relationship between the NSSA and decorrelation was demonstrated. These findings confirm the hypothesis that the statistical signature of adherent microbubbles is derived from frame-to-frame decorrelation, which is induced by flow shear forces.