基于宽频异构超声探测阵列的胎儿心动检测技术研究

Monitoring to the heart of the fetus and establishing cardiogram database in pregnancy have great significance on diagnosis of a baby’s congenital heart disease at an early date. There exists some problems like the high transmitted power and poor detectivity of weak signal in the current medical ultrasonic detecting technology , so the technology cannot be used to monitor the fetuses’ cardiogram persistently. In this project, we propose to study the wideband heterogeneous active ultrasonic transducer based on the basic principle of the Shannon information theory and the characteristics of ultrasonic transducers : ① The joint of piezoelectric ultrasonic transducers with different center frequency to build broadband transmitting transducer and study the drive circuit of specialized miniaturization. ② With the acoustic pressure information transferred into frequency information, we can use the parameter estimation which can approach the theoretical bound to extract information and realize the active CMUT receiving sensor in digital frequency . ③ CMUT transducer build receiving array and design dedicated low noise preamplifier for each transducer , thus getting integrated active receiving sensor array. ④ Cardiogram retrieval algorithm based on wideband heterogeneous active ultrasonic transducer. The proposed project will rely on the national mobile ultrasonic detection engineering technology center, which has very good experiment conditions.Our preliminary research includes the circuit system design, acoustic signal processing and detection, which provides a solid foundation for this project. Heterogeneous broadband active ultrasonic sensor has the features of sending and receiving probe separated, transmitting in wide frequency band, receiving with high sensitivity. It can be used in cardiogram ultrasonoic monitoring in early pregnancy .

在孕期对胎儿心脏进行监测，建立心动图数据库对及早诊断胎儿先心病具有重要意义。现有医学超声探测技术发射功率较大、微弱信号检测能力弱，不能用于持续的胎儿心动监测。本项目以香农信息论和超声换能器特性为依据，研发基于宽频异构超声探测阵列的胎儿心动检测：①将不同中心频率的压电超声换能器拼接，构建宽频发射换能器，并研发专门的小型化驱动电路。②将CMUT的声压信息转换为频率信息，以逼近理论界的参数估计算法提取该信息，实现基于数字频率的有源CMUT接收传感器。③CMUT换能器组建接收阵列，为每一个换能器研制专用低噪声前置放大器，实现集成有源接收传感阵列。④基于异构宽频超声传感器的心动图反演。项目依托国家移动超声探测工程技术研究中心，具有良好实验条件。申请人及项目组成员长期从事电路系统设计、超声探测研究，基础扎实。异构宽频有源超声传感器收发探头分离、信号频带宽、接收灵敏度高，可用于胎儿心脏形成初期心动监测。

在孕期对胎儿心脏进行监测，建立心动图数据库对及早诊断胎儿先心病具有重要意义。现有医学超声探测技术在发射功率、接收灵敏度、检测精度等方面不适合用于持续的胎儿心动监测。本项目以香农信息论和超声换能器特性为依据，研发了基于宽频异构超声探测阵列的关键技术及检测系统，主要研究成果包括：1、通过大量实验，基于不同中心频率的压电超声换能器，组建了宽频异构超声换能器；2、研制了多子频带的专用发射驱动电路；3、基于CMUT换能器，组建了接收检测阵列，研制了专用低噪声前置放大器，实现了“背贴式”集成有源CMUT 接收阵列。4、提出了将CMUT输出的声压检测信息转换为数字频率检测信息以逼近理论界的参数估计信息提取技术，基于此项技术实现了宽频超声数字频率式CMUT阵列检测电路系统；5、研制了用于阵列检测电路系统的专用低功耗无线收发关键电路；6、提出了可用于超声阵列心动图反演的频率估计算法，满足微弱信号检测要求。项目依托国家移动超声探测工程技术研究中心开展。发表论文7篇，并参加了相关方面的国际会议。将上述理论成果与实际应用相结合，提出了超声检测、信号采集、信号调理、频率估计等方面的发明专利共21件，其中15件已授权，6件发明专利已申请。依托取得的授权专利，主持开展一项专利成果转化项目，金额80万元。项目成果可提高低信噪比下回波检测精度，后续开展工程实现，完成整机试制，进一步开展用于胎儿心脏形成初期心动监测实验。