MRI Pulse Sequence Planning with Pre-calculated Stimulation Limits
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Solution Overview
Problem
Current magnetic resonance imaging (MRI) systems face challenges in efficiently planning and preparing MRI procedures due to complex physiological limitations and the need to avoid nerve stimulation, leading to increased computational effort and potential delays, especially in time-critical situations.
Innovation Solution
The method involves generating representative pulse sequence segments associated with reference gradient amplitudes and calculating maximum gradient slew rates to ensure compliance with stimulation limits. These segments are stored in a database for quick retrieval during the planning of MRI protocols, allowing for automatic adjustments to pulse sequence parameters to avoid exceeding stimulation limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex physiological limitation models are used to check pulse sequence compliance, then stimulation limit accuracy is improved, but computational time increases
Solution Approach 1:
The patent pre-calculates and stores compliance information for representative pulse sequence segments in a database before actual MRI planning. This preliminary action allows the system to retrieve pre-evaluated data during planning instead of performing complex real-time calculations, thus maintaining stimulation limit accuracy while dramatically reducing computational time required during actual procedure planning.
Solution Approach 2:
The patent creates representative pulse sequence segments that copy the essential characteristics of complex physiological limitation models. These simplified representations capture the key compliance requirements without requiring the full computational complexity of the original models, enabling fast retrieval and evaluation during MRI protocol planning while preserving the essential safety checks.
2Reliability
If gradient slew rates are limited to avoid nerve stimulation, then patient safety is improved, but measurement speed decreases
Solution Approach 1:
The patent dynamically adjusts gradient slew rate limits based on the specific pulse sequence characteristics and stimulation potential of each representative segment. Instead of applying uniform conservative limits to all gradients, the system retrieves pre-calculated optimal slew rates from the database that are tailored to each sequence type, thereby maximizing measurement speed while maintaining patient safety through sequence-specific optimization.
Solution Approach 2:
The patent changes the gradient slew rate parameters based on the retrieved compliance data from the database. By selecting appropriate slew rate values from pre-calculated ranges that satisfy stimulation limits for specific pulse sequence types, the system optimizes the balance between patient safety and measurement efficiency, allowing faster measurements without exceeding physiological thresholds.
3Measurement precision
If comprehensive pulse sequence checking is performed before MRI planning, then compliance accuracy is improved, but preparation time increases
Solution Approach 1:
The patent performs comprehensive compliance checking in advance by pre-calculating stimulation potentials and storing compliance information for representative pulse sequence segments in a database. This preliminary comprehensive evaluation eliminates the need for time-consuming checks during actual MRI planning, as the system simply retrieves pre-validated data, thus maintaining high compliance accuracy while minimizing preparation time.
Solution Approach 2:
The patent uses representative pulse sequence segments that copy the essential compliance characteristics of comprehensive pulse sequences. These representatives capture the key safety and compliance features without requiring full comprehensive analysis during planning, enabling fast retrieval of accurate compliance information from the database during MRI protocol preparation.
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 significantly reduces the computational effort required for planning MRI procedures, allowing for faster preparation and minimizing delays, even in emergency situations, while ensuring compliance with physiological limitations and avoiding nerve stimulation.
Implementation Method 1
a rapidly switched magnetic field known as the gradient field is usually superimposed on a static main magnetic field B0, that is used for initial alignment and homogenization of magnetic dipoles under examination, for the purpose of spatial resolution of the imaging signal
Implementation Method 2
The deflection is usually performed by a number of RF pulses (the abbreviation RF stands for radiofrequency), also known as excitation pulses
Implementation Method 3
The magnitude of the magnetization (for example of the transverse magnetization in a plane perpendicular to the aforementioned main magnetic field) at a specific position in the object under examination may be determined from the data at the readout point using a Fourier transform
Data Source
AI summary
A method for preparing magnetic resonance imaging of an object under examination is described. A plurality of representative pulse sequence segments are generated, each of which is associated with a reference gradient amplitude of the gradient pulse having the highest stimulation potential of the representative pulse sequence segment, and the stimulation potential of which is representative of a group of partially different pulse sequences. For each of the representative pulse sequence segments, a maximum gradient slew rate is determined for which a permitted maximum value of the stimulation potential is not exceeded. One of the representative pulse sequence segments is determined and selected, for a measurement protocol to be planned for a magnetic resonance imaging to be performed, according to the gradient amplitude of the gradient pulse having the highest stimulation potential of a pulse sequence segment of the pulse sequence on which the measurement protocol is based. The pulse sequence segment of the pulse sequence on which the measurement protocol is based is adjusted in such a way that a maximum gradient slew rate associated with the selected representative pulse sequence segment is also not exceeded by the pulse sequence segment of the pulse sequence on which the measurement protocol is based.