Deep learning-based high precision 3D ultrasound imaging for large size organ.

Three-dimensional (3D) ultrasound imaging offers a larger field of view and enables volumetric measurements. Among the versatile methods, free-hand 3D ultrasound imaging utilizing deep learning networks for spatial coordinate prediction exhibits advantages in terms of simplified device configuration and user-friendliness. However, this imaging method is restricted to predicting the relative spatial transformation between two consecutive 2D ultrasound images, resulting in substantial cumulative errors. When imaging large organs, cumulative errors can severely distort the 3D images. In this study, we proposed a labeling strategy based on the ultrasound image coordinate system, enhancing the network prediction accuracy. Meanwhile, pre-planning the scanning trajectory and using it to guide the network prediction significantly reduced cumulative error. Spinal 3D ultrasound imaging was performed on both healthy volunteers and scoliosis patients. Comparison of reconstruction results across different methods demonstrated that the proposed method improved the prediction accuracy by approximately 40% and reduced the cumulative error by nearly 80%. This method shows promise for application in various deep learning networks and different tissues and is expected to facilitate the broader clinical adoption of 3D ultrasound imaging.