Recently, in the United States as well as other countries, a shortage of obstetrician and gynecologist (ob-gyns) has grown seriously. The obstetrics and gynecology have a high burnout rate compared to other medical specialties because of increased workloads and competing for administrative demands. Then, there is a demand for assisting the procedure of prenatal care, especially ultrasonography. Although several robotic-assisted ultrasound imaging platforms have been developed, there were few platforms focusing on prenatal care. In this paper, we proposed an ultrasonography assistance robot for prenatal care to improve the workload of obstetricians and gynecologists. In prenatal care, it is crucially important to satisfy the safety for the pregnant women and fetus compared to other regions of ultrasonography. This paper serves as the proof of concept of the ultrasonography assistance robot for prenatal care by demonstrating the scan of uterus and estimating amniotic fluid volume for assessing fetus health with the fetal US imaging phantom, and clinical feasibility to one pregnant woman. As the key technology to satisfy the safety and acquired image quality, the mechanism with constant springs that the US probe can be shifted flexibly depending on the abdominal height was proposed. The proposed robot system enabled to scan the entire uterus area keeping the contact force under the force applied in clinical procedures (about 15 N) to the fetus phantom. Additionally, as the first application for evaluating fetus health automatically, the system to estimate the amniotic fluid volume (AFV) based on the acquired US images with the robot system was developed and evaluated with the fetus phantom. The result shows estimation errors within 10%. Finally, we demonstrated the robotic US scan to one pregnant woman and successfully observed the body parts of fetus.
Current standard workflows of ultrasound (US)-guided needle insertion require physicians to use their both hands: holding the US probe to locate interested areas with the non-dominant hand and the needle with the dominant hand. This is due to the separation of functionalities for localization and needle insertion. This requirement does not only make the procedure cumbersome, but also limits the reliability of guidance given that the positional relationship between the needle and US images is interpreted with their experience and assumption. Although the US-guided needle insertion may be assisted through navigation systems, the recovery of the positional relationship between the needle and US images requires the usage of external tracking systems and image-based tracking algorisms that may involve the registration inaccuracy. Therefore, there is an unmet need for the solution that provides a simple and intuitive needle localization and insertion to improve the conventional US-guided procedure. In this work, we propose a new device concept based on the ring-arrayed forward-viewing (RAF) ultrasound imaging system. The proposed system is comprised with ring-arrayed transducers and an open whole inside the ring where the needle can be inserted. The ring array provides forward-viewing US images, where the needle can be visualized at the center of the reconstructed image without any registration. As the proof of concept, we designed several ring-arrayed configurations and visualized point targets using the forward-viewing US imaging through simulations and phantom experiments. The results demonstrated the successful target visualization and indicates the ring-arrayed US imaging has a potential to improve the US-guided needle insertion procedure to be simpler and more intuitive.