CT-Free Spinal Imaging via 3D Target Registration
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Solution Overview
Problem
Conventional C-arm fluoroscopic systems in operating rooms are limited to acquiring only anteroposterior (AP) and lateral (LT) images, making it difficult to generate accurate axial views necessary for preoperative planning in spinal surgery, especially for procedures like pedicle screw insertion, without the availability of expensive CT scans.
Innovation Solution
A method and system that use a 3D target with X-ray opaque markers to determine the angular orientation and position of the C-arm, allowing for the reconstruction of virtual axial images from a small number of fluoroscopic images, augmented by surgeon input or image processing to define anatomical features, enabling the generation of CT-type information without a preoperative CT scan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If preoperative CT scan is used for surgical planning, then axial views and accurate 3D information are obtained, but expensive resources and extended procedural time are required
Solution Approach 1:
The system creates a virtual copy of the CT axial view by mathematically reconstructing it from multiple fluoroscopic images taken at different angles. The 3D target with markers enables registration of the fluoroscopic images to patient anatomy, allowing generation of virtual axial images that replicate CT information without requiring actual CT scanning during the procedure
Solution Approach 2:
The mobile C-arm fluoroscope, originally designed only for 2D AP and lateral imaging, is enhanced to perform multiple functions including acquiring images at various angles, tracking 3D target markers, and generating virtual axial views through software processing, replacing the need for dedicated CT equipment in the operating room
2Productivity
If mobile C-arm fluoroscope is used for imaging, then procedural time and resource requirements are reduced, but axial views necessary for accurate surgical planning cannot be acquired
Solution Approach 1:
The system acquires fluoroscopic images at multiple angular dimensions around the patient's anatomy. By collecting 2D projection data from various angles and using 3D reconstruction algorithms, the system generates virtual axial views that provide the missing dimensional information needed for accurate surgical planning without requiring physical movement to a CT scanner
3Measurement precision
If CT imager is located in operating room, then immediate axial imaging is possible, but equipment size and cost are prohibitive
Solution Approach 1:
The system extracts only the essential imaging function needed for axial view generation from the complex CT scanner. Instead of bringing the entire CT system into the operating room, the solution uses a simplified mobile C-arm fluoroscope combined with software-based 3D reconstruction algorithms to produce the necessary axial imaging information
Solution Approach 2:
The system uses multiple low-cost fluoroscopic images taken at different angles as substitutes for a single expensive CT scan. These individual fluoroscopic images are inexpensive to acquire and can be rapidly captured, with their combined information processed to create virtual axial views that replace the need for costly CT equipment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and safe surgical procedures by providing CT-type information of adequate quality, allowing for precise positioning of surgical tools like pedicle screws without the need for extensive imaging, reducing procedural time and resource requirements.
Implementation Method 1
providing an X-ray source to generate fluoroscopic images of the region of the anatomical feature of the subject
Implementation Method 2
disposing a target having an array of X-ray opaque markers in a three dimensional pattern in the region of the anatomical feature of the subject
Data Source
AI summary
A system and method for generating three dimensional CT-type information from a conventional C-arm fluoroscope imaging system. A small number of fluoroscope images are used, taken from angles whose pose is determined by means of a three-dimensional target attached to the region of interest, aided by the participation of the surgeon or an image processing routine to pinpoint known anatomical features in the region of interest of the patient. This procedure enables the reconstruction of virtual images in any desired plane, even in planes other than those accessible by the C-arm imaging process, such as the axial plane of a vertebra. Use of this system and method of marking of the feature to be treated in a small number of angularly dissimilar images, enables the generation of CT-type information which can be used to accurately align a robotically guided surgical tool with the anatomical feature.