Cerebrovascular Reactivity Detection via Stimulus Segmentation
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Solution Overview
Problem
Current methods lack sensitivity in detecting abnormal cerebrovascular reactivity and vascular pathology, as they fail to accurately assess changes in cerebral blood flow responses to vasoactive stimuli, particularly in identifying reductions in cerebrovascular reactivity.
Innovation Solution
A system that generates a series of vasoactive stimuli increments or decrements, combined with an imaging system providing sufficient spatial and time resolution, uses an algorithm to analyze the response signals, focusing on a specific sub-range of the stimulus to compute a quantitative measure of cerebrovascular reactivity, which is more sensitive to detecting reductions, and visually represents these findings on a CVR map.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the full range of vasoactive stimulus response is analyzed, then the overall cerebrovascular reactivity can be assessed, but the sensitivity to detect reductions in vascular reactivity is reduced
Solution Approach 1:
The patent segments the vasoactive stimulus response into a specific sub-range (upper portion) that is most sensitive to detecting reductions in cerebrovascular reactivity. By dividing the full stimulus range into segments and focusing analysis on the upper sub-range where vascular pathology is most detectable, the system achieves higher measurement precision without requiring complete analysis of the entire response curve, thus reducing computational complexity.
Solution Approach 2:
The patent applies local quality by concentrating the data analysis focus on a specific local portion (upper sub-range) of the vasoactive response curve where the sensitivity to detect vascular pathology is highest. This localized analysis approach allows the system to optimize detection precision in the critical region without processing the entire response profile, effectively resolving the contradiction between precision and complexity.
2Reliability
If a comprehensive conceptual model linking vascular pathology and blood flow changes is used, then the accuracy of detecting pathophysiological changes is improved, but the complexity of the imaging and analysis system increases
Solution Approach 1:
The patent extracts the essential elements of the comprehensive conceptual model by isolating the key relationship between vasoactive stimulus changes and cerebral blood flow responses. By taking out and focusing on the critical components of this model (the stimulus-response relationship in the upper sub-range), the system achieves reliable detection of pathophysiological changes without implementing the full complexity of a complete conceptual model, thus maintaining accuracy while reducing system complexity.
Data Source
AI summary
A system for detecting an abnormality in a subject's cerebrovascular response to a vasoactive stimulus in at least one region of interest (ROI) of the subject's brain The system comprises a system for generating the vasoactive stimulus (SVS), the SVS including a gas delivery device and a control system operable to deliver controlled amounts of carbon dioxide effective to attain at least one of a series of targeted increments or decrements in the subject's PetCO2, for a series of respective intervals; an imaging system comprising an MRI scanner for generating response signals corresponding to the subject's vasoactive response to the vasoactive stimulus; and a computer for analyzing the response signals, the computer including program code for computing at least one value representing a quantitative measure of the subject's cerebrovascular reactivity for the ROI, wherein the at least one value is obtained for a specific portion of the subject's vasoactive response in the ROI, the specific portion of the subject's vasoactive response corresponding to a sub-series of the at least one of a series of targeted increments or decrements in the subject's PetCO2, the sub-series characterized in that the specific portion of the subject's vasoactive response is the portion sensitive to quantifying a reduction in cerebrovascular reactivity.