Dataset: Impact of pulsed-wave-Doppler velocity-envelope extraction techniques on classification of complete fetal cardiac cycles

The pulsed-wave Doppler (PWD) signal is used as a reference for the mechanical activity of the heart and several validated parameters are used in clinical practice, most of which are evaluated by cardiologists based on visual inspection alone. Specific datasets have also been established of the simultaneous recordings of Doppler ultrasound and fetal electrocardiography. These all require the development of software tools that can automatically identify complete and meaningful fetal cardiac cycles to enable measurements. Several works in the literature have reported investigations of the extraction of the PWD velocity envelopes. The work "Impact of pulsed-wave-Doppler velocity-envelope tracing techniques on classification of complete fetal cardiac cycles", by the same authors, focus on the selection and comparison of different steps in the signal processing chain that lead to the PWD envelopes, which are used as inputs for the detection of complete heartbeats.
Here, we presents the dataset that has been used for the validation of the methodology. The data were collected from the fetal echocardiographic examination of 25 low-risk pregnant volunteers at gestational weeks ranging from the 21st to the 27th, from which we obtained a total of 43 PWD traces. All images and data are anonymous. The PWD images were collected at the Division of Pediatric Cardiology, San Michele Hospital, Cagliari, Italy. The study was approved by the Independent Ethics Committee of the Cagliari University Hospital (AOU Cagliari) and performed following the principles outlined in the Helsinki Declaration of 1975, as revised in 2000. Each volunteer signed a form acknowledging their informed consent to the research protocol.
Based on the best clinical practice, we chose the five-chamber apical window. Using the apical five-chamber view, the four cardiac chambers and the first part of the aorta (assumed as a fifth chamber) can be investigated, and the diastolic and systolic functions have distinguishable morphologies in the PWD spectrum. Overall, the EA-wave indicates the mitral inflow and the V-wave the aortic outflow.
Here, the 43 images, named as imgXX.bmp. An expert pediatric cardiologist labeled all the complete and measurable fetal cardiac cycles using a custom MATLAB graphical interface, as described in "Automatic detection of complete and measurable cardiac cycles in antenatal pulsed-wave Doppler signals". The annotations are saved in the annotations.mat file, that that consists of 2 columns: the first lists the image indexes at which the cardiologist annotated the fetal cardiac cycle onset, the second specifies the image number at which the annotation is related to. A MATLAB function allows visualizing the cardiologiest's annotations on a selected PWD image or all the cardiologiest's annotations in every PWD images in the dataset.

脉冲多普勒（PWD）信号被用作心脏机械活动的参考，临床实践中使用的验证参数众多，其中大部分均由心脏病学家通过单纯的视觉检查进行评估。同时，针对多普勒超声和胎儿心电图同步记录的特定数据集亦已建立。这些数据集均需开发能够自动识别完整且具有意义的胎儿心脏周期的软件工具，以实现相关测量。文献中已有数篇关于PWD速度包络提取的研究报告。由同一作者撰写的《脉冲波多普勒速度包络追踪技术在完整胎儿心脏周期分类中的应用影响》一文，专注于信号处理链中导致PWD包络的不同步骤的选择与比较，这些包络被用作检测完整心跳的输入。在此，我们呈现了用于验证该方法的验证数据集。数据来自25名低风险孕妇的胎儿超声心动图检查，妊娠周数介于第21周到第27周之间，共获得43个PWD轨迹。所有图像和数据均保持匿名。PWD图像由意大利卡利亚里圣米歇尔医院儿科心脏病科收集。本研究已获得卡利亚里大学医院（AOU卡利亚里）独立伦理委员会的批准，并遵循1975年赫尔辛基宣言及其2000年的修订原则执行。每位志愿者均签署了知情同意书，认可研究方案。根据最佳临床实践，我们选择了五腔心尖窗。通过心尖五腔视图，可以研究四个心脏腔室和主动脉的第一部分（假定作为第五个腔室），在PWD频谱中，舒张期和收缩期的功能具有可区分的形态。总体而言，EA波表示二尖瓣流入，V波表示主动脉流出。在此，我们呈现了43幅图像，命名为imgXX.bmp。一位资深儿科心脏病学家使用定制的MATLAB图形界面，如“在产前脉冲波多普勒信号中自动检测完整和可测量的心脏周期”一文所述，对所有完整且可测量的胎儿心脏周期进行了标注。标注信息保存在annotations.mat文件中，该文件包含两列：第一列列出心脏病学家标注胎儿心脏周期起始处的图像索引，第二列指定与标注相关的图像编号。一个MATLAB函数允许在选定的PWD图像上或数据集中每幅PWD图像上可视化心脏病学家的标注。