Accurate ultrasound imaging based on range point migration method for the depiction of fetal surface

Purpose: The purpose of this study is to evaluate the performance of a modified range point migration (RPM) method using a semi-broad transmit beam for fetal surface imaging.

Methods: The conventional RPM method depicts accurate images of target surfaces by estimating the reflection point on a target surface from the path length of plural transmit-and-receive element combinations. However, the conventional RPM method depicts false images when echoes from different targets are received simultaneously. For the elimination of false images in the employment of the RPM method, we propose a modified RPM method with a semi-broad transmit beam to decrease the number of targets in each measurement region.

Results: The modified RPM method depicted two acrylic cylinders of 2 cm in diameter with a root-mean-square error (RMSE) of 0.062 mm, where the RMSE of the migration method was 0.145 mm. The modified RPM method also succeeded in depicting a 7-month fetal phantom with a RMSE of 0.058 mm relative to a 3D image acquired using optical measurement.

Conclusion: This study shows the potential of the modified RPM method in achieving accurate surface imaging of multiple targets using a semi-broad beam, indicating that the method is suitable for fetal surface imaging.