超声平面波经颅成像相位校正方法*

超声平面波经颅成像时,由于颅骨对超声传播的影响引起图像质量下降,需要对颅骨造成的超声相位畸变进行校正。为此,该文研究了两种相位补偿方法:基于近似射线声学的理论方法和基于时间反转的数值计算方法,并利用数值仿真对比了两种方法的补偿和成像效果。结果表明:无论使用近似射线法还是时间反转法,都能够有效地校正因颅骨造成的相位畸变;时间反转法成像的精度和结果要好于近似射线法,但所需的计算资源和时间都要远远大于近似射线法;两种方法与平面波相干复合方法结合都能够一定程度上提高成像的对比度和分辨率。该研究结果为超声经颅脑成像方法研究和设备研发提供了理论指导和技术支持。

A study on the phase correction method in transcranial ultrasound plane-wave imaging

In the process of transcranial ultrasonic plane wave imaging, the image quality is decreased due to the influence of skull on ultrasonic propagation, so it is necessary to correct the ultrasonic phase distortion caused by skull. For this reason, two methods of phase compensation are studied in this paper: the theoretical method based on ray acoustics and the numerical simulation method based on time reversal. The results show that both the ray-theory method and the time reversal method can effectively correct the phase distortion caused by the skull; the imaging accuracy of the time reversal method is better than that of the ray method, but the computing resources and time required are far greater than that of the ray method; both methods can improve the imaging resolution and contrast to a certain extent combined with the coherent plane-wave compounding method. The results of this study provide theoretical guidance and technical support for the research of the method and equipment of ultrasound brain imaging.