Information-Encoded Fiducial Design for Intraprocedural Detection and Registration of Medical Devices

The design philosophy of leading interventional devices and software typically employs point- or line-like fiducial markers that are detected via multiple external optical cameras and/or the primary medical imaging system employed in the procedure (MRI, CT, fluoroscopy, etc.). Fiducial markers with characteristic geometric signals encoded into their physical design can provide more robust information on device location and orientation than point or line signals at lower imaging resolutions while leveraging the volumetric imaging capabilities of MRI and CT to circumvent the need for additional external camera hardware in the operating room. This work describes efforts to develop unique geometric fiducial designs and software methods to detect and determine their orientation based on volumetric MR-imaging. Using these methods, a single MR scan can be used to localize and orient specific medical devices autonomously, rather than relying on multimodal imaging or semi-manual detection methods. These results have been validated in a series of MRI scans using human cadaver heads and fruit-based phantoms, successfully detecting and isolating the device fiducial in 8/8 T2w MRI scans, and coregistering the signal to an orthonormal template with a Dice-based evaluation metric of 0.819. These methods have the potential to accelerate imageguided surgeries by improving automated detection and registration methods to reduce the number and/or duration of required scans while minimizing the amount of supplemental hardware (external optical cameras).