MRI Gradient Echo Train for Silicone-Fat Separation
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Solution Overview
Problem
Current MRI techniques face difficulty in distinguishing silicone implants from surrounding body fat due to their similar chemical shifts, making it challenging to obtain clear images in medical imaging.
Innovation Solution
The method involves obtaining an MRI gradient echo train of at least three echo data sets, producing phase error maps through 2-point Dixon separation, and modifying echo data sets to image distinct chemical species such as fat, water, and silicone without using inversion or suppression pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI techniques are used to image silicone implants, then the imaging process is simple and fast, but the ability to distinguish silicone from surrounding fat is poor due to similar chemical shifts
Solution Approach 1:
The patent segments the imaging process into multiple echo acquisitions with different timing parameters. By acquiring at least three echo data sets with specifically designed echo spacings, the method divides the complex task of distinguishing three chemical species (fat, water, silicone) into manageable sequential steps, where each echo contributes specific information that becomes separable through subsequent processing.
Solution Approach 2:
The patent adds the time dimension to the imaging process by utilizing multiple echo times in the gradient echo train. Instead of relying solely on spatial or spectral dimensions, the method exploits the temporal evolution of phase differences between chemical species at different echo spacings. This temporal dimension provides additional discrimination capability that enables separation of silicone from fat despite their similar chemical shifts.
2Measurement precision
If multiple echo data sets are acquired to separate chemical species, then the ability to image distinct species improves, but the imaging time increases
Solution Approach 1:
The patent maintains continuous useful action by acquiring multiple echo data sets within a single gradient echo train without requiring separate scans or repeated excitations. The continuous acquisition of echoes at different spacings from one excitation pulse maximizes the utilization of the available signal, allowing precise chemical species separation while minimizing the loss of time that would occur with multiple separate acquisitions.
3Measurement precision
If phase error maps are produced through 2-point Dixon separation, then the accuracy of chemical species imaging improves, but the processing complexity increases
Solution Approach 1:
The patent performs preliminary action by generating phase error maps through 2-point Dixon separation as an intermediate step before final chemical species imaging. This preliminary processing establishes accurate phase reference information that simplifies subsequent separation operations. By preparing the phase error correction in advance, the method reduces the overall computational burden compared to attempting direct three-way separation without intermediate phase mapping.
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 allows for separate imaging of silicone and fat, excluding water, by generating accurate phase error maps, enabling clearer differentiation and improved image resolution in MRI scans.
Implementation Method 1
In magnetic resonance imaging (MRI), human or other animal tissue is subjected to a uniform magnetic field, i.e., a polarizing field B0, so that the individual magnetic moments of particle spins in the tissue attempt to align with the polarizing field, but precess about the field in random order at their characteristic Larmor frequency
Implementation Method 2
the individual magnetic moments of particle spins in the tissue attempt to align with the polarizing field, but precess about the field in random order at their characteristic Larmor frequency
Implementation Method 3
In order to form a pixelated image for human interpretation, gradient magnetic fields, Gx, Gy, Gz, are applied to localize the tissue response to B1
Implementation Method 4
If the tissue is subjected to an RF magnetic field, i.e., excitation field B1, which defines an x-y plane and varies at a frequency near a Larmor frequency of selected particles, the net aligned moment, or 'longitudinal magnetization' of those selected particles, may be rotated, or 'tipped', into the x-y plane to produce a net transverse magnetic moment
Implementation Method 5
After B1 is terminated, the tipped spins 'relax' back into the precession defined by B0, and, as a result, produce RF signals
Implementation Method 6
The phase shift of a particular material's TE from the TE of water, at a given intensity of B0, is known as that material's 'chemical shift.'
Implementation Method 7
obtain an MRI gradient echo train of at least three echo data sets at differing phase angles
Data Source
AI summary
A method that includes obtaining an MRI gradient echo train of at least three echo data sets at differing phase angles; producing a plurality of phase error maps among the at least three echo data sets; and imaging at least three distinct chemical species based on the plurality of phase error maps.