4D MR Angiography Post-Processing for Simultaneous Arterial and Venous Imaging
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Solution Overview
Problem
Conventional MR imaging methods for cerebrovascular diseases are inefficient, requiring long examination times and often resulting in unsatisfactory images due to artifacts, particularly for venography, which can delay diagnosis and treatment in acute stroke situations.
Innovation Solution
A method for simultaneously implementing 3D subtraction MR arteriography and MR venography through post-processing of 4D MR angiography image data, using subtraction and color-coding techniques to separate and visualize arteries and veins, reducing scan time and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MR arteriography and MR venography are performed separately, then arterial and venous images can be obtained, but the examination time becomes long (7 to 10 minutes or more)
Solution Approach 1:
The patent combines arterial and venous imaging into a single 4D MR angiography examination. Multiple phases (arterial, capillary, venous) are acquired sequentially within one examination protocol, allowing both arterial and venous information to be obtained simultaneously from the same dataset, thereby reducing total examination time from 7-10 minutes to a single scan session.
Solution Approach 2:
The patent employs dynamic contrast-enhanced 4D MR angiography that captures temporal information throughout the contrast agent circulation. By acquiring images at multiple time points corresponding to different physiological phases (arterial, capillary, venous), the system dynamically separates arterial and venous structures based on their distinct temporal enhancement patterns rather than requiring separate static acquisitions.
2Measurement precision
If conventional MR venography is performed, then venous structures can be visualized, but image quality deteriorates due to artifacts and arterial signal contamination
Solution Approach 1:
The patent segments the contrast enhancement process into distinct temporal phases: arterial phase, capillary phase, and venous phase. By analyzing the time-intensity curves and separating images according to these phases, the method isolates venous structures from arterial signal contamination, achieving clean venous imaging without the need for separate venography protocols.
Solution Approach 2:
The patent uses time-intensity curves as an intermediary to objectively determine phase transition points. By measuring signal intensity changes over time at representative locations and identifying characteristic patterns (peak times, enhancement rates), the system automatically separates arterial and venous phases, eliminating subjective judgment and reducing artifacts.
3Loss of time
If 4D MR angiography is performed, then hemodynamic information can be obtained in short scan time, but arteries and veins cannot be displayed separately
Solution Approach 1:
The patent leverages the dynamic temporal information inherent in 4D MR angiography to separate arteries and veins post-acquisition. By analyzing the temporal evolution of signal intensity throughout the contrast agent circulation, the system extracts arterial phase images (early enhancement), capillary phase images (intermediate enhancement), and venous phase images (late enhancement), thereby obtaining separate arterial and venous visualizations from a single dynamic dataset acquired in short scan time.
Solution Approach 2:
The patent adds the temporal dimension to the spatial 3D imaging, creating 4D data that encompasses space and time. This temporal dimension provides the additional information needed to distinguish between arterial and venous structures based on their different enhancement kinetics, allowing separate visualization of both vessel types from a single 4D acquisition without requiring multiple separate scans.
Data Source
AI summary
A simultaneous implementation method of 3D subtraction magnetic resonance (MR) arteriography, 3D subtraction MR venography, and color-coded 4D MR angiography through post-processing of image information of 4D MR angiography according to an embodiment of the present disclosure may reduce scan time required to individually obtain an MR arteriography and an MR venography. In addition, not only anatomical information of arteries but also more accurate anatomical information of veins and more detailed hemodynamic information may be obtained.