Motion-Compensated Wavelet Angiography for Cardiac Pulse Waves
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Solution Overview
Problem
Existing angiographic techniques are poorly suited for spatiotemporal reconstruction of moving vascular pulse waves in vascular objects undergoing large-scale motion, such as those caused by a beating heart.
Innovation Solution
The method involves obtaining a series of angiographic image frames at a rate faster than cardiac frequency, applying optical flow techniques to track pixel displacement, and generating a spatiotemporal reconstruction of cardiac frequency angiographic phenomena to compensate for motion in vascular structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing angiographic techniques are used to capture vascular structures, then the imaging process is simple, but the techniques are ill-suited for spatiotemporal reconstruction in vascular objects undergoing large-scale motion
Solution Approach 1:
The patent applies dynamic motion compensation by tracking the movement of vascular structures across multiple angiographic frames. Optical flow algorithms calculate pixel displacement vectors to model the dynamic motion of vessels, enabling accurate spatiotemporal reconstruction despite large-scale cardiac motion. This transforms the static imaging approach into a dynamic one that adapts to moving targets.
Solution Approach 2:
The system performs preliminary motion estimation and compensation before final image reconstruction. By pre-calculating motion trajectories and applying motion correction transforms to the angiographic sequence, the system prepares the data in advance for accurate wavelet angiography reconstruction, separating motion effects from hemodynamic information.
2Measurement precision
If angiographic images are acquired at faster than cardiac frequency, then temporal resolution is improved, but measurement of hemodynamic pulse waves becomes more difficult due to large-scale motion
Solution Approach 1:
The patent replaces direct mechanical measurement of pulse wave propagation with an optical-based motion tracking system. Optical flow algorithms analyze pixel intensity variations across frames to infer vessel wall motion and blood flow patterns, substituting mechanical sensors with computational optics to measure hemodynamic parameters in moving vessels.
Solution Approach 2:
The system introduces optical flow field maps as an intermediary between the raw angiographic images and the final pulse wave measurements. These flow fields serve as a mediator that decouples the motion information from the hemodynamic information, allowing separate analysis of vessel motion and blood flow even at high temporal resolution.
3Reliability
If motion tracking is applied to vascular structures, then motion compensation is achieved, but computational complexity increases
Solution Approach 1:
The patent segments the vascular tree into distinct regions or segments for independent motion tracking. By dividing the complex vascular network into manageable segments, the optical flow computation is performed locally on smaller image regions, reducing overall computational complexity while maintaining accurate motion compensation for each vessel segment.
Solution Approach 2:
The system applies motion tracking selectively to only those vascular regions where large-scale motion is expected (e.g., near the heart), rather than uniformly across the entire field of view. This partial application of motion compensation reduces computational burden while still achieving reliable motion correction for the most affected areas.
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
This approach enables accurate spatiotemporal reconstruction of vascular pulse waves in moving vascular objects, improving angiographic imaging by effectively compensating for large-scale motion.
Implementation Method 1
applying an optical flow technique to the angiographic image frames to generate a plurality of paths corresponding to a displacement of respective pixels from image frame to image frame
Data Source
AI summary
Methods and systems are provided for extracting cardiac frequency angiographic phenomena for an unconstrained vascular object from an angiographic study. In one example, a computer may obtain a series of angiographic image frames obtained at a rate faster than cardiac frequency. Each image frame may comprise a plurality of pixels, and each pixel may have a corresponding intensity. The computer may apply an optical flow technique to the angiographic image frames to generate a plurality of paths corresponding to a displacement of respective pixels from image frame to image frame. The computer may further generate a spatiotemporal reconstruction of cardiac frequency angiographic phenomena based on the plurality of paths and the corresponding intensities associated with respective pixels of the paths, and output for display the spatiotemporal reconstruction of cardiac frequency angiographic phenomena in one or more images.