Sub-millisecond MRI Temporal Resolution via Phase Encoding
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Solution Overview
Problem
Current magnetic resonance imaging (MRI) technologies are unable to capture dynamic processes with sub-millisecond temporal resolution, limiting access to important physical and biological processes occurring on this timescale.
Innovation Solution
The method involves phase-encoding of MRI signals within an MRI system, digitizing multiple time points, and reconstructing time-resolved images using phase-encoded data, allowing for sub-millisecond temporal resolution through advanced image reconstruction techniques and synchronized data acquisition with cyclic events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI time-efficient strategies are used, then temporal resolution can be improved to tens of milliseconds, but sub-millisecond temporal resolution remains inaccessible
Solution Approach 1:
The patent segments the image reconstruction process by acquiring data at multiple discrete time points within a single TR period. Instead of acquiring complete k-space data for each time frame, the method divides the acquisition into N time points per TR cycle, with each time point capturing a portion of the dynamic process. This segmentation enables sub-millisecond temporal resolution by reconstructing images from these divided time point measurements.
Solution Approach 2:
The patent employs periodic action by repeating the phase-encoded signal acquisition at multiple time points within each TR cycle. The method acquires phase-encoded signals at N different time points (t1, t2, ..., tN) within a single TR period, and repeats this process across M cycles. This periodic sampling at sub-millisecond intervals enables capture of rapid dynamic processes while maintaining the periodic nature of MRI signal acquisition.
2Measurement precision
If phase-encoded signals are acquired at multiple time points, then sub-millisecond temporal resolution is achieved, but the number of signals required increases
Solution Approach 1:
The patent applies universality by making each phase-encoded signal serve multiple functions. A single phase-encoded signal acquired at a specific time point contributes to multiple image reconstructions across different cycles. The method reuses the same phase-encoded signal template across M cycles, with each cycle providing temporal sampling at N time points. This multi-functional use of signals reduces the total number of acquisitions needed compared to conventional methods.
Solution Approach 2:
The patent changes the temporal sampling parameters by acquiring data at N discrete time points within each TR cycle instead of continuous acquisition. The method varies the sampling density and timing parameters (N time points per TR, M cycles) to optimize between temporal resolution and total acquisition time. This parameter optimization enables efficient sampling of rapid dynamics without requiring excessive signals.
3Measurement precision
If advanced image reconstruction techniques are used, then sub-millisecond temporal resolution is achieved, but computational complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the phase-encoded signal templates before the actual dynamic process acquisition. The method prepares the phase-encoding gradients and signal acquisition parameters in advance, so that during the actual experiment, only temporal sampling is needed without real-time complex gradient calculations. This preliminary preparation reduces the computational burden during the reconstruction phase.
Solution Approach 2:
The patent uses copying by creating and storing reference phase-encoded signal templates that are reused across multiple cycles. Instead of performing full reconstruction calculations for each individual signal, the method copies the phase-encoding pattern and applies it systematically across M cycles with N time points each. This copying approach simplifies the reconstruction process by reducing redundant calculations.
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 enables the capture of cyclic dynamic events with sub-millisecond resolution, improving the ability to visualize rapid biological processes such as cardiac motion and neuronal currents, which were previously inaccessible due to limitations in temporal resolution.
Implementation Method 1
encoding spatial information into an MRI signal by manipulating a phase of the MRI signal within an MRI system
Implementation Method 2
Manipulation of the MRI signal phase can be performed by a phase-encoding gradient pulse or a non-linear gradient applied prior to the acquisition of the MRI signal
Data Source
AI summary
A system and method for producing a series of time-resolved magnetic resonance (MR) images is set forth. The system can perform method steps of encoding spatial information into an MRI signal by manipulating a phase of the MRI signal within an MRI system, generating and outputting a phase-encoded MRI signal over time by digitizing a plurality of time points in the MRI signal, repeating the generating and outputting step for a plurality of phase-encoded signals, each phase-encoded signal in synchrony with a trigger, producing a plurality of digitized time points, and reconstructing a series of time resolved MR images, each image of the series of MR images at one specific time point selected from the plurality of digitized time points for each phase-encoded step. Each image in the series of time-resolved MR images corresponding to a specific time point in a cyclic event.