Myocardial Blush Evaluation Using Static ROI and Fluorescence Intensity

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Solution Overview

Problem

Conventional methods for evaluating myocardial blush in tissue are time-consuming and unreliable, especially when the heart is beating, as they require tracking moving anatomy and are sensitive to intensity outliers and blood vessel contributions.

Innovation Solution

A method using a static Region-of-Interest (ROI) with statistical techniques to eliminate intensity outliers and measure fluorescence intensity within a defined range, allowing for robust perfusion evaluation independent of ROI size and position, and tracking blood vessels through spline functions and edge-detection algorithms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional digital subtraction angiography (DSA) methods are used to quantitatively characterize kinetics of dye entering the myocardium, then measurement precision can be achieved, but the evaluation process becomes extremely time-consuming and difficult to perform on a beating heart

Engineering Contradiction:

Improvequantitative characterization of dye kineticsVSAvoidevaluation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts and isolates the myocardial tissue signal from the complex angiographic image by defining a specific region of interest (ROI) that excludes blood vessels and other structures. This allows direct measurement of myocardial blush without the time-consuming subtraction process, achieving both precision and speed.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of subtracting background structures from the image as in conventional DSA, the patent inverts the approach by directly analyzing the myocardial tissue signal within a defined ROI, measuring the fluorescence intensity changes without requiring complex image processing steps.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If conventional methods track moving anatomy to evaluate myocardial blush, then measurement can be performed on a beating heart, but reliability decreases due to sensitivity to intensity outliers and blood vessel contributions

Engineering Contradiction:

Improveability to evaluate on beating heartVSAvoidrobustness against intensity outliers

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by defining a specific region of interest (ROI) with particular characteristics - excluding blood vessels and selecting only myocardial tissue. This localized approach ensures that measurements are taken from the correct tissue type, improving reliability by eliminating contamination from blood vessel signals and intensity outliers.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent performs preliminary action by pre-defining the ROI boundaries and characteristics before analyzing the fluorescence kinetics. This preliminary setup ensures that only appropriate myocardial tissue is included in the measurement, making the method robust against intensity outliers and blood vessel contributions from the start of the analysis.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a static Region-of-Interest (ROI) is used with statistical techniques to eliminate intensity outliers, then reliability of perfusion evaluation is improved, but the complexity of the measurement process increases

Engineering Contradiction:

Improverobustness of perfusion evaluationVSAvoidcomplexity of statistical processing

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by using statistical thresholds and criteria to identify and exclude intensity outliers from the measurement. By changing the parameter selection criteria (e.g., excluding pixels above or below certain intensity percentiles), the method achieves robustness against outliers while maintaining a relatively simple implementation through standard statistical operations.

Inventive Principle:

Principle #35Parameter changes

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 efficient and accurate determination of myocardial perfusion and blood vessel perfusion changes over time, providing reliable data for assessing cardiac function improvement during medical procedures without requiring real-time tracking of moving anatomy.

Implementation Method 1

images recorded following injection of fluorescent dyes

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentUS11564583B2Method for evaluating blush in myocardial tissue

Publication Date: 2023.01.31 STRYKER CORP

AI summary

Vessel perfusion and myocardial blush are determined by analyzing fluorescence signals obtained in a static region-of-interest (ROI) in a collection of fluorescence images of myocardial tissue. The blush value is determined from the total intensity of the intensity values of image elements located within the smallest contiguous range of image intensity values containing a predefined fraction of a total measured image intensity of all image elements within the ROI. Vessel (arterial) peak intensity is determined from image elements located within the ROI that have the smallest contiguous range of highest measured image intensity values and contain a predefined fraction of a total measured image intensity of all image elements within the ROI. Cardiac function can be established by comparing the time differential between the time of peak intensity in a blood vessel and that in a region of neighboring myocardial tissue both pre and post procedure.