A fast co-registration scheme between camera and MRI for MRI-guided surgery.

The co-registration between an optical tracker and Magnetic Resonance Imaging (MRI) space is an indispensable step for MRI-guided surgery. In this study, with a focus on RGB cameras as the tracker, we introduce an innovative co-registration scheme for tracker-to-MRI integration. Firstly, we design a cube-shaped registration model that is equipped with an ArUco marker on its exterior for RGB camera detection and houses four water blobs inside for MRI calibration. Secondly, we employ a line scan pulse sequence for the localization and reconstruction of the water blobs. Lastly, we establish the transformation relationship between the camera and MRI coordinate systems. Our registration scheme was implemented on a 0.35T MRI system, accompanied by a magnetically shielded RGB camera. In comparison to conventional image domain-based phantom blob reconstruction techniques, the line scanning method showcased lower registration errors and achieved scanning speeds over ten times faster. In needle localization accuracy experiments, the needle tip position, as determined by the ArUco marker on the handle, deviated by a mere 1.008 mm from its actual MRI scan position. Our results highlight the considerable potential for cost-effective RGB cameras in MRI-guided surgeries. Moreover, our registration scheme is not confined to RGB cameras and can be generalized to other optical trackers by simply substituting the corresponding marker. The proposed scheme promises to streamline and automate the co-registration process, thereby reducing surgery preparation time and bolstering the clinical applicability of MRI-guided surgeries.