T1 Mapping Signal Selection for MRI Precision
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Solution Overview
Problem
Current T1 mapping methods, such as the MP2RAGE method, face challenges in accurately measuring a range of T1 values without folding, especially at higher values, due to spatial non-uniformity of RF transmission pulses, which affects the precision of T1 maps generated by MRI apparatuses, particularly at higher magnetic field strengths.
Innovation Solution
The proposed solution involves an image processing apparatus that uses complex product and ratio signal values calculated from data acquired using the MP2RAGE method, with different TI periods, to derive T1 values by selecting appropriate complex product signal values based on complex ratio signal values, thereby avoiding folding of T1 values without altering image taking conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If MP2RAGE method is used to reduce spatial non-uniformity influence, then measurement precision is improved, but T1 value folding occurs at higher T1 values
Solution Approach 1:
The patent divides the T1 value range into multiple segments (first T1 value range and second T1 value range) and selects different complex product signal values for each segment based on complex ratio signal values. This segmentation allows accurate T1 measurement across the full range without folding by choosing appropriate signal values for each T1 segment.
Solution Approach 2:
The patent changes the selection criterion for complex product signal values based on complex ratio signal values. By dynamically selecting which complex product signal value to use based on the complex ratio signal value magnitude, the system adapts to different T1 ranges and avoids folding while maintaining measurement precision.
2Measurement precision
If higher magnetic field strength is used, then image quality is improved, but spatial non-uniformity of RF transmission pulses increases
Solution Approach 1:
The patent introduces complex ratio signal values as an intermediary to select appropriate complex product signal values. This intermediary mechanism allows the system to compensate for spatial non-uniformity effects at higher magnetic field strengths by adapting the signal selection based on the ratio of different signal components.
Solution Approach 2:
The patent changes the parameter selection strategy by using complex ratio signal values to determine which complex product signal values to use. This adaptive parameter change allows accurate T1 measurement at higher magnetic field strengths where spatial non-uniformity is more significant.
3Ease of operation
If fixed T1 value range is used for analysis, then processing is simplified, but T1 values outside this range cannot be accurately measured
Solution Approach 1:
The patent segments the T1 value measurement into multiple ranges (first and second T1 value ranges) with different complex product signal values. This segmentation enables accurate measurement across the full T1 spectrum while maintaining a systematic processing approach that is not overly complex.
Solution Approach 2:
The patent makes the signal value selection dynamic based on complex ratio signal values rather than using a fixed range. This dynamic adaptation allows the system to automatically adjust to different T1 values without requiring manual configuration, balancing simplicity with versatility.
Data Source
AI summary
An image processing apparatus according to an embodiment includes processing circuitry. The processing circuitry is configured to obtain one or more complex product signal values each indicating a signal value of a complex product and a complex ratio signal value indicating a signal value of a complex ratio calculated in units of pixels by using first data and second data successively acquired by implementing a gradient echo method after an Inversion Recovery (IR) pulse is applied and to derive a T1 value of each of the pixels from one of the complex product signal values selected on the basis of the obtained complex ratio signal value.