MR Scanner SAR Control via Posture Detection

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Solution Overview

Problem

Magnetic resonance (MR) imaging technologies face challenges in safely scanning infants and young children due to higher risks of side effects such as body burns, vision loss, and nerve function loss, necessitating improved methods to manage specific-absorption rate (SAR) and noise thresholds during MR scans.

Innovation Solution

A system and method that determine the posture of an object, calculate and adjust a pulse sequence's SAR distribution model, and ensure it meets safety conditions, while also managing noise levels by adjusting pulse sequence parameters, using a combination of SAR and noise models to optimize scanning parameters for safe MR imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If MR imaging is performed on infants and young children, then medical diagnosis capability is improved, but the risk of side effects such as body burns, vision loss, and nerve function loss increases due to higher SAR absorption

Engineering Contradiction:

Improvemedical diagnosis capabilityVSAvoidside effects (body burns, vision loss, nerve function loss)

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary determination of the object's posture and preliminary calculation of SAR distribution before executing the actual MR scan. This allows the system to predict potential safety issues in advance and adjust scanning parameters preemptively to avoid harmful effects during the actual imaging process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors and adjusts SAR distribution by comparing calculated SAR values against safety thresholds. When SAR exceeds acceptable levels, the system automatically modifies pulse sequence parameters and re-evaluates, creating a closed-loop control system that ensures safety while maintaining diagnostic quality.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If pulse sequence parameters are adjusted to reduce SAR distribution, then safety is improved, but imaging quality and scan efficiency may deteriorate

Engineering Contradiction:

ImproveSAR distributionVSAvoidscan efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system dynamically adjusts pulse sequence parameters based on real-time SAR calculations and object posture detection. Rather than using fixed conservative parameters, the system adapts scanning parameters optimally for each specific situation, maintaining scan efficiency while ensuring SAR remains within safe limits.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system modifies multiple pulse sequence parameters (such as flip angle, repetition time, echo time) in a coordinated manner to reduce SAR distribution. By changing parameters strategically rather than simply reducing overall scan power, the system maintains imaging quality while lowering SAR exposure.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If posture determination and SAR calculation are performed before scanning, then safety control is improved, but system complexity and processing time increase

Engineering Contradiction:

Improvesafety controlVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system uses the MR scanner's own hardware and processing capabilities to perform posture determination and SAR calculations, rather than requiring separate external devices. The scanner leverages its existing sensors and computational resources to autonomously assess safety conditions and adjust parameters, avoiding the need for additional complex external systems.

Inventive Principle:

Principle #25Self-service

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 system ensures safe MR scans by adjusting pulse sequences to meet SAR and noise thresholds, reducing the risk of adverse effects on infants and young children, thereby extending safe medical imaging capabilities for this age group.

Implementation Method 1

During MR imaging, the object can absorb a portion of the radio frequency (RF) energy emitted from the MR imaging device. This may cause body tissue to heating

Methodology Applied

Scientific EffectRadio frequency energy absorption: Absorption (EM radiation)

Data Source

PatentEP3415939B1Systems and methods for magnetic resonance scanning

Publication Date: 2024.12.18 SHANGHAI UNITED IMAGING HEALTHCARE

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AI summary

A method for medical imaging may include determining a posture of an object and obtaining a first parameter of a pulse sequence to be applied to the object. The method may also include determining, based on the posture and the first parameter, a SAR distribution model and estimating, based on the SAR distribution model and a second parameter of the pulse sequence to be applied, a SAR distribution associated with the object under the pulse sequence to be applied. The second parameter is associated with calibration of the pulse sequence to be applied. The method may further include determining whether the estimated SAR distribution meets a condition and causing, in response to a result of the determination that the estimated SAR distribution associated with the object meets the condition, a scanner to perform an MR scan on the object according to the pulse sequence.