MRI Center Frequency Correction Using Implant Region Exclusion
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Solution Overview
Problem
Existing MRI technologies face challenges in accurately detecting the resonance frequency of hydrogen atoms in water content tissues when implants like medical silicone are present, as signals from fat and silicone tissues interfere, making it difficult to set the center frequency of RF pulses effectively.
Innovation Solution
A magnetic resonance imaging apparatus and method that includes an image generating unit, a judging unit, and a correction unit to identify implant regions, correct the center frequency of RF pulses based on magnetic resonance frequency information from body regions, and use a smoothness evaluation value to differentiate between body and implant tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If saturation pulse and IR pulse are used to restrain MR signals from fat tissues and medical silicone, then resonance frequency detection is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the harmful frequency spectrum components corresponding to fat tissues and medical silicone implants from the MR signal spectrum. By identifying and eliminating these interfering components through spectral processing, the resonance frequency of water content tissues can be detected accurately without requiring complex saturation pulses or IR pulses, thus reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent replaces the mechanical/pulse-based approach (using saturation pulses and IR pulses to suppress signals) with a signal processing approach (frequency spectrum analysis and component removal). This substitution eliminates the need for complex pulse sequences while achieving the same goal of accurate resonance frequency detection, thereby reducing device complexity.
2Device complexity
If conventional frequency spectrum analysis is used, then processing simplicity is maintained, but measurement precision deteriorates due to signal mixing from implants
Solution Approach 1:
The patent converts the harmful interference from implant signals into a beneficial diagnostic tool. By analyzing the frequency spectrum and identifying characteristic frequency components corresponding to different tissues (fat, silicone, water), the system not only removes interfering signals but also provides information about tissue composition and implant presence, thereby improving measurement precision while maintaining relatively simple processing.
3Ease of operation
If automatic implant detection is implemented, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent implements a self-service detection system where the MRI apparatus automatically analyzes its own acquired signals to detect implants and adjust imaging parameters. The system uses the MR signal spectrum itself to identify the presence of implants and determine appropriate frequency corrections, eliminating the need for manual intervention or additional specialized detection hardware, thus improving ease of operation with minimal increase in device complexity.
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
Enables precise automatic detection of implants and accurate setting of the center frequency of RF pulses, improving image quality by distinguishing between body and implant regions, even when implants interfere with signal detection.
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 MR signals generated due to the excitation
Implementation Method 2
a resonance frequency is detected based on a peak frequency of a frequency spectrum of MR signals acquired under the resonance frequency measuring sequence
Data Source
AI summary
According to one embodiment, a magnetic resonance imaging apparatus includes an image generating unit, a judging unit and a correction unit. The image generating unit receives, from an object, a magnetic resonance signal caused by transmission of an RF pulse to cause a nuclear magnetic resonance, and generates image data of the object based on the magnetic resonance signal. The judging unit identifies an implant region where an implant part exists inside the object, based on the image data. The correction unit acquires magnetic resonance frequency information from a body region which is a region inside the object excluding the implant region, and corrects a center frequency of the RF pulse based on the magnetic resonance frequency information.