论文标题
胎儿循环的心血管流量建模的参数估计工具
Parameter estimation tools for cardiovascular flow modeling of fetal circulation
论文作者
论文摘要
通常,临床医生根据其专业知识来评估胎龄的正确血液动力学行为和胎儿健康,并在多普勒胎儿波形定义的某些指数的支持下。尽管这种方法在大多数情况下都表现出令人满意的,但它可以在更先进的技术(即数值分析和仿真)的帮助下得到很大的改进。限制分析的另一个关键方面是,临床医生依靠临床检查期间观察到的数量有限的多普勒波形。此外,使用简单的速度指标来推导胎儿心血管系统的可能故障可能会产生误导性,这是基于仅统计分析(与生理范围比较)的胎儿评估,而没有任何对观察到的血液动力学变化的深层生理病理学解释。在这种情况下,正确描述整个胎儿心血管系统的总体数学模型的使用将绝对有所帮助:通过针对临床浮雕上的生理模型参数,我们可以深入了解完整系统。模型参数的校准也可能有助于制定患者特定于胎儿病理的患者。在当前的工作中,我们基于使用合成数据的两种不同优化方法开发了可靠的参数估计算法。特别是,我们通过使用该模型获得的胎儿血流和压力的时间跟踪来处理识别集团胎儿循环模型最重要参数的反问题。这代表了基于胎儿循环的闭环数学模型识别算法的模型参数的准确性的第一项方法学工作,并为算法在临床数据中的应用开辟了道路。
Usually, clinicians assess the correct hemodynamic behavior and fetal well-being during the gestational age thanks to their professional expertise, with the support of some indices defined for Doppler fetal waveforms. Although this approach has demonstrated to be satisfactory in the most of the cases, it can be largely improved with the aid of more advanced techniques, i.e. numerical analysis and simulation. Another key aspect limiting the analysis is that clinicians rely on a limited number of Doppler waveforms observed during the clinical examination. Moreover, the use of simple velocimetric indicators for deriving possible malfunctions of the fetal cardiovascular system can be misleading, being the fetal assessment based on a mere statistical analysis (comparison with physiological ranges), without any deep physio-pathological interpretations of the observed hemodynamic changes. The use of a lumped mathematical model, properly describing the entire fetal cardiovascular system, would be absolutely helpful in this context: by targeting physiological model parameters on the clinical reliefs, we could gain deep insights of the full system. The calibration of model parameters may also help in formulating patient-specific early diagnosis of fetal pathologies. In the present work, we develop a robust parameter estimation algorithm based on two different optimization methods using synthetic data. In particular, we deal with the inverse problem of recognizing the most significant parameters of a lumped fetal circulation model by using time tracings of fetal blood flows and pressures obtained by the model. This represents a first methodological work for the assessment of the accuracy in the identification of model parameters of an algorithm based on closed-loop mathematical model of fetal circulation and opens the way to the application of the algorithm to clinical data.