Ultrasound imaging of extracellular matrix remodeling for assessing congestive heart failure

我们已经开发了一个系统，分析超声射频信号的基础上混沌理论。该系统被用于分析来自人类心肌的超声信号，以显示（1）在心肌病患者的心肌中超声信号显示准周期性而不是混沌性质，以及（2）在心脏肥大患者中长期施用醛固酮阻滞剂之后准周期性质改变为混沌性质。由于醛固酮受体阻滞剂可以减轻心肌纤维化，我们的数据可以解释为基于混沌研究的超声射频信号分析提供了一个有用的心肌纤维化指标。为了建立心肌纤维化在高血压衰竭心脏中的评估价值，我们建立了一个心肌纤维化导致左心室收缩和舒张功能障碍的模型。在该模型中，心肌纤维化与心肌炎性变化和活性氧增加相关。这些变化受到长期血管紧张素II阻断剂通过激活促进细胞外基质降解的酶的阻碍。这在左心室重构（扩张）的患者中尤为重要。因此，心肌纤维化似乎是心脏功能以及心脏几何形状的重要决定因素，表明心肌纤维化的评估在高血压性心力衰竭中尤为重要。目前，由于感兴趣区域的大小限制，我们的系统不适用于小动物，因此，我们正在尝试从技术方面改进该系统。

We have developed a system that analyzes ultrasound radiofrequency signals on the basis of chaos theory. This system was used to analyze the ultrasound signals derived from the human myocardium to show (1)that ultrasound signals show quasiperiodic rather than chaotic nature in the myocardium in patients with cardiomyopathy, and that (2)the quasiperiodic nature changes to chaotic nature following long-term administration of aldosterone blocker in patients with cardiac hypertrophy. Because aldosterone blocker is well known to reduce myocardial fibrosis, our data were may be interpreted that the analysis of ultrasound radiofrequency signals on the basis of chaos study provides a useful index of myocardial fibrosis.In order to establish the value of the assessment of myocardial fibrosis in the hypertensive failing hearts, we developed a model in which myocardial fibrosis causes in left ventricular systolic and diastolic dysfunction. In this model, myocardial fibrosis was associated with inflammatory changes in the myocardium and with the increase in reactive oxygen species. These changes were hampered by long-term angiotensin II blockade through the activation of the enzymes that facilitate the degradation of extracellular matrix. This was particularly important in those with left ventricular remodeling (dilatation). Thus, myocardial fibrosis appeared to be an important determinant of cardiac function as well as of cardiac geometry, indicating that assessment of myocardial fibrosis is particularly important in hypertensive heart failure.Currently, our system is not applicable to small animals because of the limitation of the size of region of interest, and therefore, we are attempting to improve the system from the technical aspect.