A real-time freehand 3D ultrasound imaging method for scoliosis assessment.

Real-time 3D ultrasound has gained popularity in many fields because it can provide interactive feedback to help acquire high-quality images or to conduct timely diagnosis. However, no comprehensive study has been reported on such an imaging method for scoliosis evaluation due to the complexity of this application. Meanwhile, the use of radiation-free assessment of scoliosis is becoming increasingly popular. This study developed a real-time 3D ultrasound imaging method for scoliosis assessment based on an incremental imaging method. In vivo experiments involving 36 patients with scoliosis were performed to test the performance of the proposed method. This new imaging method achieved a mean incremental frame rate of 82.7 ± 11.0 frames/s. The high repeatability of the intra-operator test (intraclass correlation coefficient [ICC] = 0.92) and inter-operator test (ICC = 0.91) demonstrated that the new method was very reliable. The result of spinous process angles obtained by the new method was linearly correlated (y = 0.97x, R2  = 0.88) with that obtained by conventional 3D reconstruction. These results suggested that the newly developed imaging method can provide real-time ultrasound imaging for scoliosis evaluation while preserving the comparative image quality of the conventional 3D reconstruction method.