Magnetic Resonance Fingerprinting Abdominal Quantification
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Solution Overview
Problem
Quantitative parameter measurement in abdominal MRI is challenging due to large organs, field inhomogeneities, and physiological motion, which complicates the characterization of tissue species using nuclear magnetic resonance (NMR) signals.
Innovation Solution
The method employs a magnetic resonance fingerprinting (MRF) technique that uses a series of varied pulse sequence blocks to simultaneously produce different signal evolutions in resonant species within the abdomen, allowing for the acquisition of NMR data during free breathing and comparison to a dictionary of known signal evolutions to determine quantitative values for parameters like T1, T2, and proton density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI pulse sequences are used to acquire images with various weightings, then qualitative images can be produced for radiologist interpretation, but the measurement of quantitative parameters is extremely challenging and time-consuming
Solution Approach 1:
The patent combines multiple pulse sequence blocks with different preparation phases into a single MRF acquisition sequence. Instead of acquiring separate T1-weighted, T2-weighted, and other contrast images in multiple serial scans, all signal evolutions are captured simultaneously in one breath-hold, merging what would traditionally require multiple time-consuming scans into a single efficient acquisition
Solution Approach 2:
The MRF sequence varies multiple parameters including flip angles, echo times, and inversion times across different sequence blocks. This systematic parameter variation creates distinctive signal evolutions for different tissue types, enabling quantitative parameter measurement through pattern recognition against a dictionary of known evolutions
2Loss of information
If multiple imaging planes and image types are acquired to enable radiologist diagnosis, then comprehensive disease signature assessment is possible, but the complexity of interpretation and skill requirements increase
Solution Approach 1:
The patent replaces the manual interpretation process with automated computational analysis. Instead of relying on radiologists to visually assess multiple qualitative images with varying contrasts, the MRF sequence captures signal evolutions that are automatically compared against a dictionary using pattern recognition algorithms, substituting human interpretation with machine-based quantitative analysis
Solution Approach 2:
The patent creates a digital copy or model of tissue properties through the MRF dictionary. The dictionary contains pre-calculated signal evolutions that represent different tissue types and their characteristic relaxation behaviors. By matching acquired signals against these digital models, the system objectively identifies tissue characteristics without requiring human interpretation of multiple image contrasts
3Reliability
If navigator data is acquired during free breathing to monitor physiological motion, then motion artifacts can be detected and affected partitions can be re-acquired, but the overall acquisition time and sequence complexity increase
Solution Approach 1:
The patent implements a feedback mechanism where navigator data is continuously monitored during the MRF acquisition to detect respiratory motion. When motion exceeds predetermined thresholds, the system triggers re-acquisition of affected partitions. This closed-loop feedback ensures data quality while maintaining efficiency by only re-acquiring specifically affected regions rather than the entire volume
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 rapid and accurate quantification of tissue properties in the abdomen, providing simultaneous T1 and T2 mapping in a single breath-hold, improving lesion detection and characterization while minimizing the effects of field inhomogeneities and motion artifacts.
Implementation Method 1
employing a magnetic resonance fingerprinting (MRF) technique that uses a series of varied pulse sequence blocks to simultaneously produce different signal evolutions in resonant species within the abdomen
Data Source
AI summary
A system and method for generating quantitative images of a subject using a nuclear magnetic resonance system. The method includes performing a navigator module to acquire navigator data, and performing an acquisition module during free breathing of the subject to acquire NMR data from the subject that contains one or more resonant species that simultaneously produce individual NMR signals in response to the acquisition module. The above steps are repeated to acquire data from a plurality of partitions across the volume. The navigator data is analyzed to determine if the NMR data meets a predetermined condition and if not, the above steps are repeated for at least an affected partition corresponding to NMR data that did not meet the predetermined condition. The NMR data is compared to a dictionary of signal evolutions to determine quantitative values for two or more parameters of the resonant species in the volume.