Robotic system for MRI-guided shoulder arthrography: Accuracy evaluation

This paper introduces a body mounted robotic system for MRI-guided shoulder arthrography in pediatric patients. This robotic manipulator is optimized for being accurate yet light enough to perform the contrast agent injection and joint examination imaging inside the MRI bore. The robotic manipulator has 4 degrees of freedom (DOF) providing accurate insertion trajectory of the injection needle. In shoulder arthrography procedures, contrast agent is injected under fluoroscope guidance resulting in radiation exposure which should be avoided for pediatric patients. Also after contrast agent injection typically MRI images are acquired for examination resulting in two stage procedure. The presented system allows clinicians to perform both contrast agent injection and joint examination under MRI guidance, hence completely eliminating radiation exposure from fluoroscope guidance and patient movement from X-Ray/CT room to MRI suite. The presented system contains no ferrous components and is considered MR-Conditional. The bench-top accuracy evaluation of the robotic manipulator shows average pose error of 1.22 mm in position and 1 degree in orientation at the needle tip.