Myocardial Mass Normalization for Nuclear Medicine Ischemia Detection
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Solution Overview
Problem
Existing methods for detecting myocardial ischemia using nuclear medicine imaging underestimate conditions with diffusely lowered myocardial blood flow, particularly in patients with multivessel ischemic cardiomyopathy, due to inappropriate assumptions about tracer distribution.
Innovation Solution
A method that normalizes myocardial nuclear medicine image data using a value related to the size of the heart, such as heart weight, to accurately reflect cardiac function and correct for tracer accumulation, allowing for more precise evaluation of blood flow changes under stress and at rest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing SUV normalization using body mass is used, then general quantitative evaluation is enabled, but tracer accumulation in myocardia is not accurately reflected
Solution Approach 1:
The patent changes the normalization parameter from body mass to myocardial mass. This is achieved by calculating myocardial volume from segmented myocardial images and converting it to myocardial mass using a density coefficient (1.05 g/cm³). The SUV is then recalculated using myocardial mass instead of body mass, which accurately reflects the actual tracer distribution in myocardial tissue and improves both measurement precision and detection reliability.
2Ease of manufacture
If simple body mass normalization is applied, then calculation is simplified, but patients with diffusely lowered myocardial blood flow are underestimated
Solution Approach 1:
The patent replaces the simple body mass parameter with a more accurate myocardial mass parameter. The myocardial mass is obtained by segmenting the myocardium from the image, calculating its volume, and multiplying by the density coefficient. This parameter change maintains computational feasibility while significantly improving the accuracy of ischemic condition evaluation, particularly for patients with diffuse blood flow reduction.
3Adaptability or versatility
If existing normalization methods are used, then general applicability is maintained, but multivessel ischemic cardiomyopathy is not properly detected
Solution Approach 1:
The patent modifies the normalization parameter from body mass to myocardial mass, which is calculated by segmenting the myocardium and applying density conversion. This parameter change maintains the SUV framework's versatility while specifically improving detection reliability for multivessel ischemic cardiomyopathy, as the myocardial-specific normalization accurately captures regional perfusion deficits characteristic of this condition.
Data Source
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AI summary
Provided is a highly reliable technique for the evaluation of ischemic conditions. A preferred embodiment is a nuclear medicine measurement protocol in which the administration of a radiopharmaceutical agent and radiation measurement are performed twice at rest and under stress. In the nuclear medicine measurement protocol, radiation collection is performed without radiopharmaceutical agent administration before the second radiopharmaceutical agent administration, and the result is used to correct the nuclear medicine measurement result after the second radiopharmaceutical agent administration.