CEST Data Fitting Using MT Reference Extrapolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing CEST imaging methods struggle to accurately eliminate interference effects such as Magnetization transfer (MT) and other non-Lorenzian curves, as they rely on approximations that are not valid under various experimental conditions.
Innovation Solution
A CEST data fitting method using a two-pool model based on an extrapolated semisolid magnetization transfer reference signal, which integrates the MT effect into the Bloch-McConnell equation, allowing for accurate fitting and removal of interference by calculating the difference between a fitted curve and an experimental curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If MTRasym method is used to calculate CEST signals by subtracting reference signal from labeling signal, then the calculation process is simple, but other interference effects such as MT effect of macromolecules cannot be completely eliminated
Solution Approach 1:
The patent segments the interference effects into different components (MT effect, NOE effect, direct saturation) and models each separately using a multi-pool system. This allows selective elimination of specific interference effects while preserving the CEST signal, resolving the contradiction between simple calculation and accurate interference elimination.
Solution Approach 2:
The patent introduces a multi-pool model as an intermediary framework that includes both the CEST pool and interference effect pools (MT, NOE, DS). By fitting experimental data to this comprehensive model, the method accurately separates and eliminates interference effects while maintaining calculation feasibility, thus resolving the contradiction between simplicity and precision.
2Ease of manufacture
If Multi-pool Lorenzian fitting is used to fit each effect curve as a Lorenzian curve, then the fitting process is straightforward, but the MT effect curve which is super Lorenzian cannot be accurately represented
Solution Approach 1:
The patent changes the lineshape function parameters from fixed Lorenzian form to a more flexible functional form that can accommodate super Lorenzian MT effect curves. This allows accurate representation of the MT effect while maintaining a relatively simple fitting process through the use of modified parameter definitions in the multi-pool model.
3Measurement precision
If EMR method is used to fit the curve representing other effects except CEST effect, then the interference effects can be eliminated, but the method assumes saturation pulse is square wave and system is in steady state which are not always met
Solution Approach 1:
The patent transitions from static assumptions (square wave saturation pulse, steady state) to a dynamic framework using time-dependent differential equations in the multi-pool model. This allows the system to accurately represent and eliminate interference effects under various dynamic experimental conditions, resolving the contradiction between precision and adaptability.
4Ease of manufacture
If approximation methods are used to model experimental conditions, then the calculation is simplified, but the approximation is not valid under many experimental conditions
Solution Approach 1:
The patent extracts and explicitly models the key experimental parameters (saturation pulse waveform, relaxation times, exchange rates) in the multi-pool differential equations rather than using approximations. This removes the invalid approximations while maintaining calculation feasibility through systematic solution methods, resolving the contradiction between simplicity and validity.
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
The method effectively removes interference effects, enabling precise CEST effect values to be obtained, even when the system is not in steady state, and improves the visibility of lesions in CEST imaging.
Implementation Method 1
Chemical exchange saturation transfer (CEST) imaging is a kind of magnetic resonance molecular imaging technology, which can detect free protein and polypeptide in a living body
Implementation Method 2
other interference effects are not all equal in the reference signal and the labeling signal, such as the Magnetization transfer (MT) effect of macromolecules
Implementation Method 3
A CEST data fitting method using a two-pool model based on an extrapolated semisolid magnetization transfer reference signal, which integrates the MT effect into the Bloch-McConnell equation
Data Source
AI summary
A CEST data fitting method and apparatus based on an extrapolated semisolid magnetization transfer reference signal, and a medium, which belong to the field of magnetic resonance imaging. According to the CEST data fitting method based on an extrapolated semisolid magnetization transfer reference signal, a lineshape of an MT effect is fused into a Bloch-McConnell equation, the MT effect can be obtained by means of fitting a model that is represented by the equation, and an interference effect can be eliminated by calculating the difference between a curve that is obtained via fitting and a curve that is collected from an experiment. The Bloch-McConnell-based fitting method can take into consideration a radio frequency pulse waveform that is actually used in an experiment, and can also be used when a system is not in steady state.