Electronic Information School, Wuhan University, Wuhan, P.R. China.
Department of Medical Ultrasound, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.
BMC Med Inform Decis Mak. 2020 Sep 25;20(1):243. doi: 10.1186/s12911-020-01255-2.
Clinically, doctors obtain the left ventricular posterior wall thickness (LVPWT) mainly by observing ultrasonic echocardiographic video stream to capture a single frame of images with diagnostic significance, and then mark two key points on both sides of the posterior wall of the left ventricle with their own experience for computer measurement. In the actual measurement, the doctor's selection point is subjective, and difficult to accurately locate the edge, which will bring errors to the measurement results.
In this paper, a convolutional neural network model of left ventricular posterior wall positioning was built under the TensorFlow framework, and the target region images were obtained after the positioning results were processed by non-local mean filtering and opening operation. Then the edge detection algorithm based on threshold segmentation is used. After the contour was extracted by adjusting the segmentation threshold through prior analysis and the OTSU algorithm, the design algorithm completed the computer selection point measurement of the thickness of the posterior wall of the left ventricle.
The proposed method can effectively extract the left ventricular posterior wall contour and measure its thickness. The experimental results show that the relative error between the measurement result and the hospital measurement value is less than 15%, which is less than 20% of the acceptable repeatability error in clinical practice.
Therefore, the measurement method proposed in this paper has the advantages of less manual intervention, and the processing method is reasonable and has practical value.
临床上,医生主要通过观察超声心动图视频流来获取左心室后壁厚度(LVPWT),以捕捉具有诊断意义的单帧图像,然后根据自己的经验在左心室后壁的两侧标记两个关键点,以便计算机进行测量。在实际测量中,医生的选择点是主观的,难以准确地定位边缘,这将给测量结果带来误差。
本文在 TensorFlow 框架下构建了左心室后壁定位的卷积神经网络模型,通过非局部均值滤波和开运算对定位结果进行处理后得到目标区域图像,然后采用基于阈值分割的边缘检测算法。通过先验分析和 OTSU 算法调整分割阈值提取轮廓后,设计算法完成了左心室后壁厚度的计算机选择点测量。
所提出的方法可以有效地提取左心室后壁轮廓并测量其厚度。实验结果表明,测量结果与医院测量值之间的相对误差小于 15%,小于临床实践中可接受的重复性误差的 20%。
因此,本文提出的测量方法具有人工干预少的优点,处理方法合理,具有实用价值。