Sliding Window Reconstruction for Dynamic MRI Fat Suppression
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Solution Overview
Problem
Current fat suppression techniques in MRI, such as conventional fat saturation and Short-TI inversion recovery (STIR), are inadequate for dynamic imaging due to sensitivity to magnetic field heterogeneities and reduced signal-to-noise ratio, limiting their applicability, especially in areas like extremity and large field of view imaging.
Innovation Solution
A cyclical magnetic resonance imaging method is applied with a plurality of cycles and echoes, generating frames at a frame rate at least twice the cycle rate, using a sliding window reconstruction to maintain high temporal resolution and achieve reliable fat suppression by combining echoes from adjacent cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fat saturation or STIR imaging is used, then fat suppression is achieved, but reliability deteriorates in the presence of magnetic field heterogeneities
Solution Approach 1:
The patent applies periodic action by using cyclical magnetic resonance imaging excitation with multiple echoes acquired at different time points within each cycle. This periodic sampling at different echo times allows the system to capture phase information that can be used to correct for magnetic field heterogeneities, thereby maintaining reliable fat suppression despite field inhomogeneities.
Solution Approach 2:
The patent implements feedback by using the phase information derived from multiple echoes to dynamically adjust and correct the fat suppression process. The phase maps calculated from the echo data provide feedback that compensates for magnetic field heterogeneities, enabling reliable fat suppression even in challenging imaging conditions.
2Speed
If dynamic imaging is performed with high temporal resolution, then temporal resolution is improved, but scan time increases
Solution Approach 1:
The patent merges multiple echoes from adjacent cycles to generate frames at a frame rate at least twice the cycle rate. By combining information from multiple echoes acquired in adjacent cycles, the system achieves high temporal resolution without proportionally increasing scan time, as the echoes are acquired within the existing cyclical framework.
Solution Approach 2:
The patent uses partial action by generating frames from a subset of available echo data. Frames are constructed using echoes from adjacent cycles, which provides sufficient information for high temporal resolution imaging without requiring complete acquisition of all possible echo data, thereby optimizing the balance between temporal resolution and scan time.
3Speed
If multiple frames are generated from adjacent cycles, then temporal resolution is improved, but processing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the reconstruction process into distinct stages: acquiring multiple echoes in cyclical cycles, calculating phase maps from these echoes, and then generating frames by combining echoes from adjacent cycles. This segmented approach manages processing complexity by breaking down the overall reconstruction task into manageable, sequential steps.
Solution Approach 2:
The patent performs preliminary action by calculating phase maps from the acquired echoes before generating the final frames. This preliminary calculation of phase information simplifies the subsequent frame generation process, as the phase correction is already performed, reducing the complexity of the final reconstruction step.
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 approach provides dynamic MRI with effective fat suppression, maintaining high temporal resolution and minimizing scan time, suitable for applications like contrast-enhanced liver and breast imaging, while compensating for phase drifts and field inhomogeneities.
Implementation Method 1
exploit the difference in chemical shifts between water and fat and in order to separate water and fat into separate images
Implementation Method 2
compensating for phase drifts and field inhomogeneities
Data Source
AI summary
A method for generating dynamic magnetic resonance images is provided. A cyclical magnetic resonance imaging excitation is applied for a plurality of cycles at a cycle rate. A plurality of magnetic resonance image echoes is acquired for each cycle. A plurality of frames of images is generated from the acquired plurality of magnetic resonance echoes at a frame rate that is at least twice the cycle rate, wherein each frame of the plurality of frames is generated from a plurality of echoes and wherein some of the plurality of frames are generated from magnetic resonance image echoes of adjacent cycles.