Intravascular Ultrasound Image Reconstruction via Coplanar Projection
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Solution Overview
Problem
Conventional intravascular ultrasound (IVUS) imaging methods produce images with discontinuities and inaccuracies due to non-coplanar radial A-scan lines, resulting in distorted images with visible seams, especially at higher catheter withdrawal speeds.
Innovation Solution
The method involves reconstructing coplanar IVUS images by obtaining data from proximal, middle, and distal frames during a pullback, selecting a position along the longitudinal axis, projecting A-scan lines onto a reconstruction plane perpendicular to the axis, and determining grayscale values through weighted averages of corresponding A-scan lines from different frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional IVUS imaging methods are used with radial A-scan lines collected during pullback, then imaging speed is improved, but image quality deteriorates due to visible seams and non-coplanar data
Solution Approach 1:
The patent introduces a longitudinal dimension to the image reconstruction by projecting A-scan lines onto a reconstruction plane at a specific longitudinal position. This transforms the helical data into a coplanar representation by adding the longitudinal coordinate as a new dimension, allowing seamless image construction without seams while maintaining the speed benefits of pullback imaging.
Solution Approach 2:
The patent uses an intermediate reconstruction plane as a mediator between the helical data and the final image display. This reconstruction plane acts as a temporary representation that converts non-coplanar A-scan lines into coplanar data, enabling seamless image construction without requiring changes to the acquisition process.
2Productivity
If catheter withdrawal speed is increased, then diagnostic efficiency is improved, but seam visibility increases due to greater longitudinal position differences
Solution Approach 1:
By adding the longitudinal dimension to the reconstruction process, the patent can compensate for larger longitudinal position differences caused by higher pullback speeds. The reconstruction plane allows proper alignment and interpolation of data points even when the longitudinal displacement between consecutive A-scan lines is significant, thus reducing seam visibility while maintaining diagnostic efficiency.
3Ease of operation
If A-scan lines are displayed as coplanar despite non-coplanar collection, then image display simplicity is improved, but measurement accuracy deteriorates
Solution Approach 1:
The reconstruction plane serves as an intermediary that maintains the simplicity of coplanar display while achieving accurate measurement. It properly transforms the helical data into a coplanar representation through projection and interpolation, ensuring that both the display remains simple and the measurements remain accurate by preserving the true spatial relationships of the vessel wall.
Data Source
AI summary
Methods, devices, and systems for providing seamless, co-planar intravascular ultrasound (IVUS) images are provided. In some embodiments, the methods include projecting a first A-scan line from a distal frame onto a reconstruction plane that extends perpendicular to an imaging axis, projecting a second A-scan line parallel to the first A-scan line from the proximal frame on the reconstruction plane; and determining a grayscale value of a point on the reconstruction plane by a weighted average of the first A-scan line and the second A-scan line.