Perfusion Imaging With Remote PPG Cardiac Phase Tagging
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Solution Overview
Problem
ECG gated CT perfusion imaging is flawed due to reliance on electrical signals rather than mechanical motion, leading to inconsistent heart motion states and potential radiation artifacts, which affect data reliability.
Innovation Solution
A contactless blood pulsation parameter determiner, such as an optical camera using remote photoplethysmography, is used to determine cardiac phase without physical contact, allowing for consistent perfusion data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ECG gated CT is used for perfusion imaging, then cardiac phase consistency is improved, but data reliability deteriorates due to radiation artifacts and electrical signal limitations
Solution Approach 1:
The patent replaces the electrical ECG signal-based gating system with a mechanical motion-based gating system. Optical sensors detect actual mechanical heart wall motion to determine cardiac phase, substituting the electrical signal detection method with direct mechanical motion detection, thereby eliminating radiation artifacts affecting ECG probes while maintaining cardiac phase consistency
Solution Approach 2:
The patent introduces optical sensors as an intermediary between the heart and the imaging system. These sensors detect mechanical heart wall motion indirectly through skin surface movement or other mechanical couplings, serving as a mediator that provides accurate cardiac phase information without being exposed to x-ray radiation
2Measurement precision
If ECG probe is placed close to tissue of interest, then cardiac phase detection precision is improved, but harmful radiation effects increase
Solution Approach 1:
The patent replaces electrical signal detection with mechanical motion detection using optical sensors. These sensors measure actual mechanical heart wall motion through skin surface displacement or other mechanical indicators, eliminating the need to place electrical probes in the radiation field while maintaining or improving measurement precision
Solution Approach 2:
The patent uses optical sensors to detect and copy the mechanical motion pattern of the heart wall. By measuring skin surface movement or other external mechanical indicators that correlate with heart wall motion, the system creates a proxy measurement that accurately reflects cardiac phase without requiring direct contact with the heart in the radiation field
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
This method provides accurate and reliable perfusion data by correlating skin color variations with blood flow, eliminating interference from ECG probes and enhancing data consistency.
Implementation Method 1
a contactless blood pulsation parameter determiner configured to determine blood pulsation parameters on or near the tissue of interest without physical contact to the patient
Data Source
AI summary
Perfusion data is generated from imaging a tissue of interest. The perfusion data includes image data of a contrast agent passing through the tissue of interest. A remote photoplethysmography (PPG) device is configured to focus on a patient's area at or near the tissue of interest. The PPG device is located on a gantry and remains stationary when an X-ray source rotates during a scanning operation. The PPG device is coupled to at least one processor and a memory for storing a remote PPG software. The at least one processor is configured to execute the remote PPG software to determine, based on skin color variations due to changing blood flow conditions, at least one blood pulsation parameter within a beam projecting on the tissue of interest. The blood pulsation parameter includes a phase of a cardiac cycle. The at least one processor is further configured to execute the remote PPG software to determine at least one perfusion-pulsation parameter based on the perfusion data and the blood pulsation parameter. The perfusion-pulsation parameter includes the perfusion data tagged with the phase of the cardiac cycle in which the perfusion data is acquired.