MRI Scan Order Optimization for SAR Reduction
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Solution Overview
Problem
Conventional MRI techniques face challenges in reducing the Specific Absorption Rate (SAR) to ensure safe imaging conditions, often requiring modifications that reduce the number of slices or delay imaging, leading to inefficiencies and suboptimal imaging conditions.
Innovation Solution
An MRI apparatus and method that calculates and optimizes the scan order for multiple scans to minimize SAR values by varying the sequence of SAR-intensive scans, allowing for optimal imaging without exceeding safety criteria, thereby reducing SAR without altering individual scan conditions or introducing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pulse sequence is modified to reduce SAR value, then safety standard compliance is improved, but the number of slices is reduced leading to degraded imaging quality
Solution Approach 1:
The patent dynamically adjusts the scan order of multiple slices based on real-time SAR accumulation. Instead of using a fixed scan order, the system calculates SAR values for different scan order patterns and selects the optimal pattern that minimizes SAR while maintaining all slices. This dynamic adaptation resolves the contradiction by allowing full slice imaging (maintaining quality) while actively managing SAR through flexible reordering.
Solution Approach 2:
The patent changes the parameter of scan order arrangement to optimize SAR distribution. By varying the sequence in which slices are scanned and comparing different permutation patterns, the system finds arrangements that distribute RF energy more evenly over time, preventing SAR accumulation while preserving all imaging slices and their diagnostic quality.
2Object-affected harmful factors
If the pulse sequence is modified to reduce SAR value, then safety standard compliance is improved, but imaging time is increased leading to reduced productivity
Solution Approach 1:
The patent performs preliminary calculation of SAR values for multiple possible scan order patterns before actual imaging. By pre-evaluating different scan order permutations and selecting the optimal one in advance, the system avoids trial-and-error adjustments during scanning. This preliminary optimization ensures that the chosen scan order achieves minimum SAR without requiring additional imaging time or repeated scans.
Solution Approach 2:
The system dynamically determines the optimal scan order based on calculated SAR characteristics of different slice combinations. This dynamic optimization allows the system to adapt the scan sequence to the specific imaging scenario, achieving SAR reduction without compromising imaging speed or requiring extended scan times.
3Object-affected harmful factors
If conventional SAR reduction techniques are used, then SAR value is reduced, but the scan order is fixed leading to suboptimal imaging conditions
Solution Approach 1:
The patent implements a dynamic scan order selection system that evaluates multiple permutation patterns and adapts the scan sequence to optimize SAR distribution. Unlike fixed conventional approaches, this system can adaptively choose the best scan order pattern based on the specific imaging scenario, slice characteristics, and SAR accumulation patterns, thereby achieving both SAR reduction and optimal imaging conditions simultaneously.
Solution Approach 2:
The system changes the scan order parameter dynamically by comparing different permutation patterns and selecting the one that minimizes SAR while maintaining imaging quality. This parameter optimization allows flexible adaptation to various imaging scenarios without being constrained by fixed scan sequences, resolving the contradiction between SAR reduction and imaging condition optimization.
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 effectively reduces SAR by up to 25% by optimizing scan order, ensuring compliance with safety standards while maintaining imaging efficiency and quality, without reducing the number of slices or degrading image quality.
Implementation Method 1
MRI is an imaging method which magnetically excites nuclear spin of an object (a patient) set in a static magnetic field with an RF pulse having the Larmor frequency and reconstructs an image based on nuclear magnetic resonance signals (hereinafter referred to as MR signals) generated due to the excitation
Implementation Method 2
nuclear spin of an object (a patient) set in a static magnetic field with an RF pulse having the Larmor frequency
Data Source
AI summary
According to one embodiment, an MRI apparatus includes a calculation unit and an imaging unit. The calculation unit calculates “a value of a parameter having an upper limit” for “a plurality of patterns of scan orders for a plurality of scan operations for an object” respectively. The imaging unit generates image data for each of the scan operations by performing the plurality of scan operations based on a result of the calculation.