MRI Receiver Signal Splitting for Dynamic Range Extension
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Solution Overview
Problem
Existing MRI technologies face challenges with the Dual Scan method, which requires multiple scans for extended dynamic range, leading to instability, potential artifacts, and increased imaging time. Additionally, current ADCs are inadequate for high-channel count MRI systems, resulting in complex apparatuses and high manufacturing costs.
Innovation Solution
The proposed solution involves dividing MR signals into two or more systems, using a first ADC to process one system as is, and a second ADC to process the other system after gain adjustment. This configuration allows for AD conversion with a virtually extended dynamic range using only two types of ADCs with different gains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Dual Scan method is used to extend dynamic range, then the dynamic range is improved, but the imaging time is prolonged and apparatus stability deteriorates
Solution Approach 1:
The patent applies dynamics by making the gain adjustment variable and time-dependent. The gain adjuster dynamically changes the gain of the MR signal based on the imaging time point, transitioning from a static gain setting to a dynamic one that adapts to different stages of the imaging process, thereby extending dynamic range without requiring multiple separate scans
Solution Approach 2:
The patent applies preliminary action by performing gain adjustment before A/D conversion. The gain adjuster pre-processes the MR signal by adjusting its gain according to the imaging time point, so that when the signal undergoes A/D conversion, the dynamic range is already optimized, eliminating the need for subsequent scan repetition
2Measurement precision
If the Dual Scan method is used to extend dynamic range, then the dynamic range is improved, but apparatus stability deteriorates
Solution Approach 1:
The patent applies dynamics by making the gain adjustment variable and time-dependent. The gain adjuster dynamically changes the gain of the MR signal based on the imaging time point, transitioning from a static gain setting to a dynamic one that adapts to different stages of the imaging process, thereby extending dynamic range without requiring multiple separate scans
Solution Approach 2:
The patent applies continuity of useful action by performing the imaging process continuously without interruption. The gain adjustment occurs continuously during the imaging process based on the imaging time point, eliminating the need to stop and restart imaging, thus maintaining apparatus stability and avoiding artifacts from repeated scans
3Adaptability or versatility
If multiple ADCs are used to process signals from multiple channels, then the signal processing capability is improved, but the apparatus complexity and manufacturing cost increase
Solution Approach 1:
The patent applies universality by making a single ADC process multiple channels of MR signals. The gain adjuster enables one ADC to handle multiple signal channels by dynamically adjusting gains, eliminating the need for separate ADCs for each channel, thus reducing apparatus complexity and manufacturing cost while maintaining signal processing capability
Solution Approach 2:
The patent applies merging by combining multiple signal processing functions into a single ADC system. Instead of having separate ADCs for each channel, the invention merges the functionality into one ADC with a gain adjuster that handles multiple channels, simplifying the overall apparatus structure
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 enables high-definition image data collection without increasing the apparatus size or manufacturing costs, while extending the dynamic range without prolonging imaging time.
Implementation Method 1
a magnetic field generator configured to generate nuclear magnetic resonance in a subject
Implementation Method 2
a receiver having a receive coil configured to receive a nuclear magnetic resonance signal emitted from the subject
Data Source
AI summary
In an MRI apparatus, a dynamic range of an MR signal is extended without increasing the time for imaging nor manufacturing cost. The MRI apparatus is provided with a receiver 200 configured to perform the A/D conversion on two-system nuclear magnetic resonance signals according to a direct sampling method. The receiver 200 comprises a distributor 201 configured to divide each of the nuclear magnetic resonance signals into two-system signals, an attenuator 202 configured to attenuate an overflowed signal outputted from the distributor, and a switch 203 configured to switch between the signals having the same gain to output the switched signal. Also provided is a digital processing means having ADCs of the same number as that of the nuclear magnetic resonance signals to perform the AD conversion respectively for the two types of signals, restore the attenuated signals, and recombine the signals. After switching, the signals outputted with different gains are combined to increase the number of bits of digital data with respect to all the sampling points, thereby extending the dynamic range.