Monitoring spinal curvature in adolescent kyphoscoliosis requires regular radiographic examinations; however, the applied ionizing radiation increases the risk of cancer. Ultrasound imaging is favorable over X-ray because it does not emit ionizing radiation. Therefore, we tested an ultrasound system for spinal curvature measurement, with the help of spatial tracking of the ultrasound transducer. Tracked ultrasound was used to localize vertebral transverse processes as landmarks along the spine to measure curvature angles. The method was tested in two scoliotic spine models by localizing the same landmarks using both ultrasound and X-ray imaging and comparing the obtained angles. Close correlation was found between tracked ultrasound and radiographic curvature measurement. Differences between results of the two methods were 1.27±0.84° (average ± SD) in an adult model and 0.96±0.87° in a pediatric model. Our results suggest that tracked ultrasound may become a safer and more accessible alternative to radiographic spine monitoring in adolescent kyphoscoliosis.
