This paper presents an intraoperative MRI-guided, patient-mounted robotic system for
shoulder arthrography procedures in pediatric patients. The robot is designed to be
compact and lightweight and is constructed with nonmagnetic materials for MRI safety.
Our goal is to transform the current two-step arthrography procedure (CT/x-ray-guided
needle insertion followed by diagnostic MRI) into a streamlined single-step ionizing
radiation-free procedure under MRI guidance. The MR-conditional robot was evaluated
in a Thiel embalmed cadaver study and healthy volunteer studies. The robot was attached
to the shoulder using straps and ten locations in the shoulder joint space were selected as
targets. For the first target, contrast agent (saline) was injected to complete the clinical
workflow. After each targeting attempt, a confirmation scan was acquired to analyze the
needle placement accuracy. During the volunteer studies, a more comfortable and
ergonomic shoulder brace was used, and the complete clinical workflow was followed
to measure the total procedure time. In the cadaver study, the needle was successfully
placed in the shoulder joint space in all the targeting attempts with translational and
rotational accuracy of 2.07 ± 1.22mm and 1.46 ± 1.06 degrees, respectively. The total
time for the entire procedure was 94 min and the average time for each targeting attempt
was 20 min in the cadaver study, while the average time for the entire workflow for the
volunteer studies was 36 min. No image quality degradation due to the presence of the
robot was detected. This Thiel-embalmed cadaver study along with the clinical workflow
studies on human volunteers demonstrated the feasibility of using an MR-conditional,
patient-mounted robotic system for MRI-guided shoulder arthrography procedure. Future
work will be focused on moving the technology to clinical practice
