Relaxation Time Determination Using Forward Model Lookup Tables
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetic resonance imaging (MRI) techniques are time-consuming, expensive, and confining for patients, with long scan times required for high-spatial resolution images, which degrades the user experience and increases costs.
Innovation Solution
A system that rapidly determines relaxation times by applying a polarizing field and excitation sequence to a sample, measuring signals, and calculating relaxation times using a forward model, allowing for modified sequences and continuous calculation without Fourier transforms, enabling faster and more accurate MR imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI techniques are used to achieve high-spatial resolution images, then image quality is improved, but scan time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing lookup tables of predicted signals for various relaxation times and excitation sequences before actual imaging. During scanning, the system rapidly compares measured signals against these pre-computed tables to determine relaxation times, eliminating the need for time-consuming iterative calculations during the scan itself. This allows high-spatial resolution imaging with significantly reduced scan times.
Solution Approach 2:
The patent uses copying by creating synthetic signal models that replicate the expected MRI signal behavior for different tissue types and parameters. Instead of performing complex forward models during scanning, the system copies pre-computed signal characteristics into lookup tables, enabling rapid comparison and parameter determination while maintaining image quality.
2Measurement precision
If conventional MRI techniques are used for detailed tissue characterization, then diagnostic accuracy is improved, but cost increases
Solution Approach 1:
By pre-computing signal models and storing them in lookup tables, the system eliminates time-consuming calculations during patient scanning. This reduces scan time and operational costs while maintaining diagnostic accuracy through the use of physics-based forward models that accurately predict tissue signal behavior.
Solution Approach 2:
The patent changes parameters by using variable flip angles and multiple echo times in the excitation sequences, then rapidly determining relaxation times through comparison with pre-computed lookup tables. This approach provides accurate tissue characterization at reduced scan times and lower costs compared to conventional multi-sequence MRI protocols.
3Measurement precision
If iterative convergence methods are used to determine physical parameters, then measurement precision is improved, but computational complexity increases
Solution Approach 1:
The patent copies pre-computed signal models into lookup tables, replacing complex iterative convergence calculations with simple table lookups and comparisons. This maintains measurement precision by using accurate physics-based forward models while dramatically reducing computational complexity during the actual parameter determination process.
Solution Approach 2:
The system performs the computationally intensive forward model calculations in advance, storing results in lookup tables. During scanning, only simple comparisons are needed to determine physical parameters, reducing real-time computational complexity while maintaining the precision benefits of iterative convergence methods.
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 reduces scan times, improves user experience, and increases throughput, providing more accurate and cost-effective MRI characterization by leveraging predictive models and iterative processes.
Implementation Method 1
In MR magnetic nuclear spins may be partially aligned (or polarized) in an applied external DC magnetic field
Implementation Method 2
magnetic resonance or MR (which is often referred to as 'nuclear magnetic resonance' or NMR), a physical phenomenon in which nuclei in a magnetic field absorb and re-emit electromagnetic radiation
Implementation Method 3
nuclei in a magnetic field absorb and re-emit electromagnetic radiation
Implementation Method 4
The resulting dynamic response of the nuclear spins (such as the time-varying total magnetization) can provide information about the physical and material properties of a sample, such as one or more physical parameters associated with the sample
Data Source
AI summary
During operation, a system may apply a polarizing field and an excitation sequence to a sample. Then, the system may measure a signal associated with the sample for a time duration that is less than a magnitude of a relaxation time associated with the sample. Next, the system may calculate the relaxation time based on a difference between the measured signal and a predicted signal of the sample, where the predicted signal is based on a forward model, the polarizing field and the excitation sequence. After modifying at least one of the polarizing field and the excitation sequence, the aforementioned operations may be repeated until a magnitude of the difference is less than a convergence criterion. Note that the calculations may be performed concurrently with the measurements and may not involve performing a Fourier transform on the measured signal.