Respiratory-State MRI Binning for Motion-Resolved Organ Imaging
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Solution Overview
Problem
Existing magnetic resonance imaging (MRI) techniques struggle to accurately capture respiratory motion, particularly in regions like the thoracic, lung, abdomen, liver, pancreas, and kidney, due to variations in organ position during inhalation and exhalation, which complicates radiotherapy planning and patient comfort.
Innovation Solution
A medical system and method that utilizes respiratory-state resolved magnetic resonance imaging by binning k-space data based on both respiratory position and inhalation/exhalation state, employing a multi-dimensional k-space sampling pattern that varies with each acquisition and incorporates respiratory signals to improve image resolution and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI techniques are used to capture respiratory motion, then the scanning process can be completed, but motion artifacts and blurred images occur due to organ position variations during inhalation and exhalation
Solution Approach 1:
The patent divides the continuous respiratory cycle into discrete respiratory states (e.g., inhalation and exhalation phases) and sorts k-space data into separate bins corresponding to each state. This segmentation allows images to be reconstructed from data acquired at specific respiratory moments, eliminating motion blur caused by continuous organ movement during scanning.
Solution Approach 2:
The patent changes the sorting parameter from simple temporal ordering to respiratory-state-based categorization. By using respiratory signals (from external sensors or internal navigators) to determine the respiratory state at the time of each k-space line acquisition, the system dynamically assigns data to appropriate bins, improving image sharpness and reducing artifacts.
2Measurement precision
If respiratory gating is implemented to improve image quality, then motion artifacts are reduced, but the scanning time and complexity increase
Solution Approach 1:
The patent employs self-gating techniques where the MRI sequence itself generates navigators or uses intrinsic k-space data to determine respiratory state, eliminating the need for separate external gating systems. The same k-space data used for image reconstruction is also used to determine respiratory phase, reducing overall scan time while maintaining image quality.
Solution Approach 2:
The patent maintains continuous data acquisition throughout the scan without pausing for breath-holds or gating delays. All k-space lines are acquired continuously and then sorted into respiratory-state bins after acquisition, ensuring that the useful imaging action continues uninterrupted while still achieving motion-resolved images.
3Productivity
If k-space data is acquired continuously without respiratory sorting, then the scanning process is simple and fast, but the resulting images contain motion blur and reduced diagnostic quality
Solution Approach 1:
The patent performs preliminary sorting of k-space data into respiratory-state bins during or immediately after the acquisition process. By organizing data into state-specific bins before reconstruction, the system prepares motion-resolved datasets without requiring additional scanning time, maintaining scanning efficiency while enabling high-quality image reconstruction.
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
Enables sharper magnetic resonance images that distinguish tumors and organs at risk throughout the breathing cycle, enhancing radiotherapy planning by accurately capturing hysteresis effects and reducing motion artifacts.
Implementation Method 1
A large static magnetic field is used by Magnetic Resonance Imaging (MRI) scanners to align the nuclear spins of atoms
Implementation Method 2
Radio Frequency (RF) pulses generated by one or more transmitter coils cause a called B1 field
Implementation Method 3
RF signals are then emitted by the nuclear spins and detected by one or more receiver coils
Implementation Method 4
Additionally applied gradient fields and the B1 field cause perturbations to the effective local magnetic field
Data Source
AI summary
Disclosed herein is a medical system (100, 400) comprising: a magnetic resonance imaging system (102) configured for providing a respiratory signal. The respiratory signal is descriptive of a respiratory position as well as of inhalation and exhalation of the subject. The execution of machine executable instructions (140) causes the computational system to repeatedly: perform (200) the individual acquisition of k-space data using the magnetic resonance imaging system; receive (202) the respiratory signal; bin (204) the individually acquired k-space data into one of a predetermined number of k-space bins (148) using the respiratory signal and perform outlier rejection. Execution of the machine executable instructions further causes the computational system to reconstruct (208) a magnetic resonance image for each of the predetermined number of k-space bins to provide a respiratory-state resolved magnetic resonance image (150).