Methods and apparatus for angiographic image selection
Inventors
Lavi, Guy • Lavi, Ifat • Juran, Michael E.
Assignees
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Publication Number
US-12079994-B2
Publication Date
2024-09-03
Expiration Date
Abstract
A method and apparatus for selecting (i) an imaging angle with minimized foreshortening and/or overlap of a target region from an existing angiographic image and/or (ii) selecting an imaging angle for new images so that foreshortening and/or overlap are minimized. A viewing angle cost function is determined that defines optimal viewing angles at least with respect to minimizing foreshortening of the target region. Using the cost function, an image may be selected from among a set of images, which potentially does not match the optimal imaging angle due to the optimal imaging angle having a high cost as a result of overlapping vascular features. The selected image may have an imaging angle that corresponds to a lower cost due to less overlap compared to the optimal imaging angle.
Core Innovation
The invention relates to automatic selection of an existing angiographic image by determining a viewing angle cost function for a vascular model and a target region. A plurality of angiographic images is received together with the vascular model and the selection of the target region, and the viewing angle cost function is determined for a plurality of viewing angles with respect to the target region. An angiographic image is selected by identifying an angiographic image corresponding to a viewing angle whose cost function value is on a first, lower-cost side of a cost function threshold, and the selected image is displayed.
The viewing angle cost function penalizes foreshortening due to offsets along a first angular axis less severely than foreshortening due to offsets along a second angular axis, where the second plane is perpendicular to the first plane. The cost function is also based on a direction perpendicular to the target region minimizing foreshortening, where angles offset from the perpendicular direction increase foreshortening. In addition, the cost function accounts for viewing overlap effects with other regions of the vascular model, including rules where increased view overlap leads to increased cost.
To support overlap mitigation and orientation for candidate viewing angles, the invention introduces a shell representing a surface across which the vasculature extends, where the shell comprises a substantially ovate surface. The shell and tangent-plane based orientation are used to choose near-perpendicular viewing directions and an overlap-mitigating angular offset, and overlap detection can be performed using simulated 2D projections of the 3D vascular model.
Claims Coverage
The document identifies three independent claims. Each independent claim centers on selecting an angiographic image using a viewing-angle cost function applied to a vascular model and a target region, with image selection based on whether the viewing angle cost value is on a lower-cost side of a cost function threshold.
Threshold-based viewing-angle cost selection from existing angiographic images
Receiving a plurality of angiographic images, receiving a vascular model of a vasculature, receiving a selection of a target region of the vascular model, determining a viewing angle cost function defining cost function values for a plurality of viewing angles with respect to the target region, the cost function values including a first set located on a first, lower-cost side of a cost function threshold and a second set located on a second, higher-cost side; selecting an angiographic image from among the plurality by identifying an angiographic image corresponding to a viewing angle having a cost function value located on the first, lower-cost side of the cost function threshold; and displaying the selected image.
Foreshortening-penalizing cost function using perpendicular angular axes
Determining the viewing angle cost function values wherein the viewing angle cost function penalizes foreshortening due to offsets along a first angular axis defining rotations within a first plane less severely than it penalizes foreshortening due to offsets along a second angular axis defining rotations within a second plane perpendicular to the first plane.
Perpendicular-direction foreshortening minimization with cost threshold
Determining the viewing angle cost function based on a direction perpendicular to the target region minimizing foreshortening of the target region, and angles offset from the perpendicular direction increasing foreshortening.
Shell-based ovate surface for viewing-angle cost calculation
Determining the viewing angle cost function comprises calculating a shell representing a surface across which the vasculature extends, wherein the shell comprises a substantially ovate surface.
Across the independent claims, the inventive approach is to compute viewing-angle cost values from a vascular model and target region, partition them by a cost function threshold into lower-cost and higher-cost sides, and select an existing angiographic image based on the viewing angle falling on the lower-cost side. Dependent limitations reflect different mechanisms for foreshortening penalties and introduce a shell with a substantially ovate surface for cost calculation.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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