Dynamic Contrast Enhanced MRI with Compressed Sensing
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Solution Overview
Problem
Current dynamic contrast enhanced magnetic resonance imaging (DCE MRI) techniques face challenges in achieving fast and high-quality imaging due to limitations in fat suppression, specific absorption rate (SAR) concerns, and reduced temporal resolution caused by chemical shift encoding methods, which prolong scanning time and compromise diagnostic accuracy.
Innovation Solution
The method employs compressed sensing reconstruction techniques in combination with Dixon acquisition and chemical shift encoding in the k-space and dynamic time space, utilizing undersampling and a priori water-fat images to accelerate data acquisition and processing, while ensuring high image quality through integrated reconstruction and parallel imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chemical shift encoding approaches (Dixon methods) are used to separate water and fat signals, then fat suppression quality is improved, but scanning time is prolonged and temporal resolution is reduced
Solution Approach 1:
The patent applies partial sampling in k-space combined with compressed sensing reconstruction. Instead of acquiring complete k-space data for each Dixon encoding, only a subset of k-space lines is acquired, and the missing data is reconstructed using compressed sensing algorithms that exploit signal sparsity and temporal correlations. This reduces scanning time while maintaining water-fat separation quality.
Solution Approach 2:
The patent changes the sampling parameters by using variable density sampling patterns in k-space, where the center region is oversampled and peripheral regions are undersampled. This parameter optimization allows compressed sensing reconstruction to recover high-quality images with reduced data acquisition, thereby shortening scan time while preserving Dixon encoding effectiveness.
2Measurement precision
If multi-echo techniques are used for Dixon encoding, then water and fat signal separation is achieved, but sampling efficiency is insufficient and total scanning time is prolonged
Solution Approach 1:
The patent combines multi-echo Dixon encoding with partial k-space sampling. Instead of acquiring complete multi-echo data for all k-space lines, only selected k-space lines are acquired for each echo, reducing the total number of measurements. Compressed sensing reconstruction recovers the full water-fat separated images from this reduced dataset, improving sampling efficiency.
Solution Approach 2:
The patent performs preliminary undersampling of k-space data before reconstruction. By pre-planning the sampling pattern to prioritize central k-space regions and using compressed sensing priors, the system prepares the data in advance for efficient reconstruction, avoiding the need for complete data acquisition while maintaining separation accuracy.
3Measurement precision
If frequent B1-/B0-inhomogeneity correction is applied to maintain fat suppression quality, then imaging accuracy is improved, but specific absorption rate (SAR) limits are exceeded
Solution Approach 1:
The patent extracts and corrects B1-/B0-inhomogeneity effects during the compressed sensing reconstruction process rather than applying frequent pre-saturation pulses. By separating the inhomogeneity correction from the fat suppression RF pulses, the system achieves accurate water-fat separation without exceeding SAR limits, as the correction is performed computationally rather than through repeated RF irradiation.
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 enhances the quality of DCE MRI data, allowing for higher spatial or temporal resolution with reduced data acquisition and processing times, thereby improving diagnostic accuracy in tumor detection and breast cancer diagnosis.
Implementation Method 1
The magnetic field produces different energy levels for the individual nuclear spins in dependence on the applied magnetic field strength which spins can be excited (spin resonance) by application of an alternating electromagnetic field (RF field) of defined frequency, the so called Larmor frequency or MR frequency.
Implementation Method 2
In order to realize spatial resolution in the body, linear magnetic field gradients extending along the three main axes are superposed on the uniform magnetic field, leading to a linear spatial dependency of the spin resonance frequency.
Implementation Method 3
Dixon acquisition in a chemical shift encoding space
Data Source
AI summary
The present invention relates to a method of performing dynamic contrast enhanced magnetic resonance imaging of an object (10) with signal separation for water and fat, the method comprising acquiring magnetic resonance datasets in the k-space using Dixon acquisition in a chemical shift encoding space and dynamic time resolution in a dynamic time space, wherein the dataset acquisition is performed employing undersampling, wherein the method further comprises: applying a compressed sensing reconstruction technique in the k-space, the chemical shift encoding space and the dynamic time space, said compressed sensing reconstruction resulting in reconstructed datasets, —performing Dixon reconstruction on the reconstructed datasets and dynamic contrast analysis on the Dixon reconstructed datasets.