Patient-Mounted Needle Guide Motion Compensation
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Solution Overview
Problem
Current patient-mounted needle guide devices face accuracy issues due to patient motion and internal organ displacement during image-guided percutaneous procedures, as they do not effectively account for constant and periodic motion or tissue displacement caused by needle insertion, leading to potential misalignment and reduced targeting accuracy.
Innovation Solution
An MRI-compatible patient-mounted needle guide system with a fully-automated image-based device-to-image registration algorithm that continuously adjusts the needle trajectory to compensate for patient motion and internal organ displacement, using fiducial markers for real-time tracking and re-registration, ensuring accurate needle placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a patient-mounted needle guide device is used, then the device is less vulnerable to patient motion compared to room-mounted systems, but the device still experiences displacement due to body surface motion and internal organ movement
Solution Approach 1:
The system continuously tracks the position of fiducial markers attached to the needle guide device and compares them with the planned trajectory. When displacement is detected due to patient motion, the system automatically calculates correction vectors and adjusts the needle insertion path in real-time, creating a closed-loop feedback system that maintains accuracy despite motion
Solution Approach 2:
The system dynamically changes the parameters of the needle trajectory (position, angle, depth) based on real-time detection of device displacement. By adjusting these parameters in response to measured motion, the system compensates for the harmful effects of patient movement and maintains accurate targeting
2Measurement precision
If automated image-based registration with fiducial markers is implemented, then device-to-image registration accuracy is improved, but the system complexity increases
Solution Approach 1:
Fiducial markers serve as intermediary objects that bridge the physical needle guide device and the digital image space. These markers are easily detectable in images and provide a common reference framework, simplifying the registration process by reducing it to marker detection and coordinate transformation rather than complex feature matching
Solution Approach 2:
The system creates a digital copy of the fiducial marker positions from images and uses this copy to calculate the transformation between device and image coordinate systems. This copying approach simplifies registration by working with easily measurable marker positions rather than complex anatomical feature correspondence
3Reliability
If motion compensation through continuous re-registration is performed, then targeting accuracy is maintained throughout the procedure, but the procedure time increases
Solution Approach 1:
The system performs re-registration at periodic intervals rather than continuously, balancing the need for accuracy with procedural efficiency. By updating the registration at regular time intervals or after detecting significant motion events, the system maintains accuracy while minimizing the time overhead compared to continuous re-registration
4Device complexity
If the needle trajectory is mechanically fixed by the patient-mounted guide, then the insertion mechanism is simplified, but the system cannot adapt to internal organ displacement caused by needle insertion
Solution Approach 1:
The system transitions from a static, mechanically fixed trajectory to a dynamic, software-adjustable trajectory. The needle guide maintains its simple mechanical structure for insertion, but the targeting system dynamically recalculates the trajectory based on detected organ displacement, separating the mechanical simplicity from the computational adaptability
Data Source
AI summary
Exemplary methods, apparatus, and systems are disclosed for automated registration and motion compensation of patient-mounted needle guide medical devices using fiducial markers, and processing algorithms where a re-registration step is provided. These methods, apparati, and systems adaptively compensate for the displacement of the medical device and/or target location due to the patient movement or internal organ motion.