Free-Breathing BOLD CMR for Myocardial Perfusion Imaging
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Solution Overview
Problem
Current cardiovascular imaging methods, such as BOLD CMR, are limited by slow temporal resolution and sensitivity to breathing motion and heart rate variability, making it difficult to accurately assess myocardial perfusion dynamics during cardiac stress tests.
Innovation Solution
A non-ECG-gated, free-breathing, beat-to-beat, respiratory and cardiac phase-resolved, T2-based BOLD CMR sequence using a low rank tensor (LRT) framework is developed, allowing for continuous monitoring of BOLD changes during cardiac stress exams and reducing patient discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional BOLD CMR imaging is used to monitor myocardial perfusion, then contrast accumulation can be detected, but the temporal resolution is insufficient to accurately evaluate dynamic perfusion processes
Solution Approach 1:
The imaging process is segmented into multiple cardiac phases (e.g., end-diastole, end-systole) acquired sequentially. Each phase is imaged separately with optimized parameters, allowing high temporal resolution within each phase while maintaining overall imaging efficiency through the segmented acquisition approach.
Solution Approach 2:
The imaging protocol uses periodic acquisition patterns synchronized with the cardiac cycle. By acquiring images at specific periodic intervals corresponding to cardiac phases and using ECG gating, the method achieves high temporal resolution for dynamic perfusion evaluation while maintaining productivity through efficient periodic sampling.
2Reliability
If ECG-gated imaging is used to reduce heart rate variability effects, then image quality improves, but patient discomfort increases and scanning time extends
Solution Approach 1:
The imaging protocol dynamically adapts to the patient's natural breathing pattern rather than requiring rigid breath-holding. By using free-breathing acquisition with respiratory compensation techniques and retrospective gating, the system maintains image quality while allowing patients to breathe naturally, thereby improving comfort and reducing scanning time.
Solution Approach 2:
The system incorporates real-time feedback from respiratory sensors and ECG signals to dynamically adjust acquisition timing and parameters. This feedback mechanism allows the imaging protocol to compensate for breathing motion and heart rate variability without requiring strict patient compliance with breath-holding instructions, thus improving both comfort and image quality.
3Ease of operation
If free-breathing imaging is used to improve patient comfort, then breathing motion artifacts increase and image quality deteriorates
Solution Approach 1:
Respiratory compensation techniques serve as intermediaries between free-breathing acquisition and image reconstruction. By using external respiratory sensors to monitor breathing patterns and applying retrospective gating or motion correction algorithms, the system eliminates breathing motion artifacts while maintaining the benefits of free-breathing acquisition, thus preserving both comfort and image quality.
Solution Approach 2:
The protocol replaces mechanical breath-holding requirements with software-based motion compensation. By substituting the mechanical constraint of breath-holding with computational methods (retrospective gating, motion correction algorithms), the system achieves high-quality images from free-breathing data, improving patient comfort without sacrificing image quality.
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 enables rapid time-resolved assessment of myocardial perfusion, improving image quality and reducing artifacts, thus providing more accurate diagnostics of cardiovascular diseases.
Implementation Method 1
Blood Oxygen Level Dependent Cardiovascular Magnetic Resonance (BOLD CMR) imaging is an emerging method for monitoring myocardial perfusion without contrast agents
Data Source
AI summary
The invention provides various methods for imaging a subject's cardiovascular system. The imaging methods may be used to diagnose or prognose various cardiovascular diseases in the subject, without contrast agents or radioactive tracers.