Myocardial Perfusion Assessment via Segment Normalization
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Solution Overview
Problem
Current methods for quantitatively assessing myocardial perfusion using cardiac MRI are unreliable due to insufficient left ventricle input functions, often caused by patient breathing or non-linear scanner behavior, leading to inaccurate myocardial perfusion reserve index (MPRI) calculations.
Innovation Solution
The method involves dividing the myocardium into segments, determining time-intensity profiles, and using normally perfused segments as a reference for contrast agent uptake, calculating relative maximum upslopes, and deriving myocardial perfusion parameters independently of the left ventricle input function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If myocardial perfusion is calculated from first-pass myocardial perfusion images using LV input function, then perfusion parameters can be derived, but measurement reliability deteriorates due to insufficient LV input function caused by patient breathing or non-linear scanner behavior
Solution Approach 1:
The patent introduces an intermediary reference segment (a normally perfused myocardial segment) to mediate between the contrast agent injection and the perfusion measurement. Instead of directly using the LV input function which is unreliable, the method uses the reference segment's time-intensity profile as an intermediate reference to normalize and calculate perfusion parameters, thereby eliminating the direct dependency on the unreliable LV input function
Solution Approach 2:
The patent changes the reference parameter from LV input function maximum upslope to the maximum upslope of a normally perfused myocardial segment. This parameter change allows the system to bypass the unreliable LV input function and use a more stable reference that is less affected by breathing artifacts and scanner non-linearity
2Productivity
If LV input function maximum upslope is used for normalization, then perfusion parameters can be calculated, but measurement reliability deteriorates due to non-linear scanner behavior at high image intensity levels
Solution Approach 1:
The patent introduces an intermediary reference segment (a normally perfused myocardial segment) to mediate between the contrast agent injection and the perfusion measurement. Instead of directly using the LV input function which is unreliable, the method uses the reference segment's time-intensity profile as an intermediate reference to normalize and calculate perfusion parameters, thereby eliminating the direct dependency on the unreliable LV input function
Solution Approach 2:
The patent changes the reference parameter from LV input function maximum upslope to the maximum upslope of a normally perfused myocardial segment. This parameter change allows the system to bypass the unreliable LV input function and use a more stable reference that is less affected by breathing artifacts and scanner non-linearity
Data Source
AI summary
In a computer-readable medium, device and method for quantitative assessment of cardiac perfusion, a myocardium is depicted on a series of cardiac images and is divided into image segments. A cardiac perfusion parameter is determined for each of the image segments. At least one image segment with a normal perfusion parameter value is selected. The cardiac perfusion parameters of the remaining image segments are normalized based on the normal perfusion parameter value of said image segment with normal perfusion. The perfusion parameter can be a maximum upslope of a time-intensity profile for distribution of a contrast agent in said myocardium. A normal maximum upslope is derived for at least one image segment with normal perfusion and a relative maximum upslope is calculated for each other segment with relation to the normal maximum upslope.