Dual-Echo T2-Weighted MRI with Dixon Reconstruction for Fat and Fluid Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current whole-body magnetic resonance imaging (MRI) techniques for cancer detection face challenges such as exposure to ionizing radiation, limited spatial resolution, and increased radiation exposure in younger patients, as well as geometric distortions and signal-to-noise ratio limitations, particularly at 3 T field strength.
Innovation Solution
A dual-echo T2-weighted imaging technique using single-shot turbo spin echo with Dixon reconstruction and shared-field-map processing for simultaneous fat and fluid suppression, achieving robust fat/water separation and improved signal-to-noise ratio, allowing for high-resolution, fast imaging with minimal geometric distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If diffusion-weighted imaging with background suppression (DWIBS) is used for whole-body cancer detection, then lesion conspicuity is improved, but geometric distortions increase due to large B0 inhomogeneities
Solution Approach 1:
The patent changes the echo time parameter by acquiring images at both short and long TE values, then uses subtraction to eliminate fat signal while preserving lesion information. This parameter-based approach avoids the geometric distortion problem of DWIBS while maintaining lesion conspicuity
Solution Approach 2:
The patent segments the signal into fat and non-fat components by acquiring in-phase and out-of-phase images at different echo times. This segmentation allows selective suppression of fat signal while preserving lesion signal, resolving the contradiction between lesion conspicuity and geometric distortion
2Measurement precision
If short tau inversion recovery (STIR) is used for fat suppression, then tumor conspicuity is improved, but signal-to-noise ratio decreases requiring multiple signal averages
Solution Approach 1:
The patent uses periodic acquisition of in-phase and out-of-phase images at different echo times, leveraging the periodic nature of magnetic resonance signal evolution. This allows fat suppression through subtraction while maintaining adequate signal-to-noise ratio without requiring multiple signal averages
Solution Approach 2:
The patent performs preliminary fat suppression by acquiring and processing in-phase and out-of-phase images before the actual tumor detection imaging. This preliminary action removes fat signal interference, improving tumor conspicuity without degrading the signal-to-noise ratio of the tumor signal
3Reliability
If spectral pre-saturation using inversion recovery (SPIR/SPAIR) is used for fat suppression, then signal-to-noise ratio is improved, but inhomogeneous fat suppression occurs at 3 T due to increased B0 inhomogeneities
Solution Approach 1:
The patent changes from frequency-selective fat suppression (SPIR/SPAIR) to echo-time-based fat suppression. By acquiring images at different echo times and subtracting them, the patent achieves uniform fat suppression that is insensitive to B0 inhomogeneities, resolving the contradiction between signal-to-noise ratio and fat suppression uniformity at 3 T
4Reliability
If conventional T2-weighted imaging is used, then fluid signal is preserved, but fluid signal mimics lesions reducing detection accuracy
Solution Approach 1:
The patent extracts and removes fluid signal by acquiring images at short and long echo times and subtracting them. This extraction approach eliminates fluid signal that mimics lesions while preserving lesions with restricted diffusion, improving lesion detection accuracy without completely eliminating fluid signal
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 method enables efficient and reliable metastatic cancer detection with improved lesion conspicuity and quantitative fat-fraction mapping in less than 7 minutes, outperforming diffusion-weighted imaging with background suppression in terms of detection and localization of lesions.
Implementation Method 1
placing a subject into a substantially homogeneous magnetic field in the imaging space of a magnetic resonance imager
Implementation Method 2
acquiring four images, in-phase (IP) and out-of-phase (OP) at a short and a long echo time (TE) using a single-shot turbo spin echo
Implementation Method 3
processing at least a pair of in-phase (IP) and out-of-phase (OP) images at a short and a long echo time (TE) using single-shot turbo spin echo using a Dixon reconstruction
Implementation Method 4
processing at least a pair of in-phase (IP) and out-of-phase (OP) images at a short and a long echo time (TE) using single-shot turbo spin echo using a shared-field-map Dixon reconstruction
Implementation Method 5
subtracting the long TE water-only image from the shared-field-map Dixon reconstruction from the short TE water-only image from the Dixon reconstruction to provide a fluid attenuation
Data Source
AI summary
The present invention includes a method and apparatus for improved magnetic resonance imaging with simultaneous fat and fluid suppression of a subject comprising: acquiring four images, in-phase (IP) and out-of-phase (OP) at a short and a long echo time (TE) using a single-shot turbo spin echo from one or more magnetic resonance imager excitations: processing at least a pair of IP and OP images at a short and a long TE using single-shot turbo spin echo using a Dixon reconstruction; processing the pair of IP and OP images; subtracting the long TE water-only image from the shared-field-map Dixon reconstruction from the short TE water-only image to provide a fluid attenuation; processing water-only and fat-only images at the short and long TE to generate quantitative fat-fraction map; and reconstructing one or more 3D magnetic resonance images.