EM Tracking Calibration Validation for TEE Probes
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Solution Overview
Problem
The accuracy of electromagnetic tracking of 3D trans-esophageal echo (TEE) probes can degrade due to unexpected EM field distortions, physical movement of sensors, and sensor breakdowns, leading to incorrect motion estimation and guidance during minimally invasive cardiac procedures.
Innovation Solution
An image-guided system continuously validates the calibration matrix between the 3D TEE probe and electromagnetic position sensors by comparing image-based and tracking-based volume motions, triggering a warning for invalid calibrations to ensure accurate navigation and guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If EM tracking is used to facilitate minimally invasive cardiac therapy, then the capability for intra-procedural beating heart surgery is improved, but the reliability of motion estimation deteriorates due to EM field distortions and sensor issues
Solution Approach 1:
The system continuously monitors the calibration matrix between the TEE probe and EM position sensors during the procedure. By comparing the known rigid spatial relationship with measured positions, the system provides feedback on calibration accuracy and alerts operators when distortion exceeds thresholds, enabling real-time quality control of EM tracking
Solution Approach 2:
The patent introduces an intermediary calibration monitoring system that acts as a mediator between the EM tracking system and the surgical guidance system. This intermediary layer validates the calibration matrix and detects field distortions without interfering with the primary EM tracking function, allowing continuous quality control
2Adaptability or versatility
If advanced interventional guidance systems with multiple modules are developed, then the functionality is improved, but the complexity of maintaining calibration accuracy increases
Solution Approach 1:
The calibration monitoring system performs self-validation by automatically comparing the known rigid spatial relationship of the calibration matrix with measured EM sensor positions. The system independently detects calibration drift and alerts operators without requiring external verification, enabling autonomous quality control in complex multi-module systems
3Reliability
If continuous monitoring of calibration accuracy is implemented, then the reliability of guidance system is improved, but the computational load and processing time increase
Solution Approach 1:
The system implements partial monitoring by continuously validating only the critical calibration matrix parameters rather than performing complete recalibration checks. This selective monitoring approach maintains reliability by focusing on key calibration indicators while reducing computational overhead and processing time
Data Source
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AI summary
A probe (20) generates a plurality of image volumes (13i, 13j) of an anatomical object (10) within a coordinate system (11) and an imaging device (21) generates imaging data (22) representative of the image volumes (13i, 13j) of the anatomical object (10). A position sensor (30) is attached to the probe (20), and a tracking device (31) generates tracking data (22) representative of a tracking of the position sensor (30) within the coordinate system (11). A registration device (40) executes a validation testing of a calibration matrix (51) associated with a spatial relationship between the image volumes (13i, 13j) and the position sensor (30). The validation testing includes a testing of an absolute differential between an image based volume motion (VMIB) and a tracking based volume motion (VMTB) relative to a calibration threshold (CT).