MRI Reconstruction via Deep Subspace Learning

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Solution Overview

Problem

Current deep learning-based MRI image reconstruction methods face memory limitations, restricting their ability to handle high-dimensional data due to high memory and computational requirements, which prevents them from efficiently processing higher-dimensional MRI techniques.

Innovation Solution

Deep subspace learning reconstruction (DSLR) method that converts high-dimensional sensor data into a compressed representation, using simpler neural networks for reconstruction in the compressed domain, integrating MRI physics-based modeling for data consistency, and decompressing at the end for image visualization, allowing for memory-efficient training and inference across various dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If deep neural networks are used for MRI image reconstruction, then image quality and reconstruction speed are improved, but memory requirements increase significantly

Engineering Contradiction:
Improvereconstruction speedVSAvoidmemory requirements
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent segments the high-dimensional reconstruction problem into lower-dimensional subproblems by decomposing the data into a compressed representation with reduced dimensionality. This allows the neural network to process and reconstruct data in a simplified space, reducing memory requirements while maintaining reconstruction quality and speed benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the high-dimensional data into a compressed representation with lower dimensionality, effectively moving the problem to a different dimensional space. This dimensionality reduction enables the use of simpler neural networks with fewer parameters, thereby reducing memory requirements while preserving the ability to reconstruct high-quality images.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If deep neural networks are trained on high-dimensional data, then reconstruction accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improvereconstruction accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the computational task by decomposing the high-dimensional data into a compressed representation. This segmentation allows the neural network to operate on lower-dimensional data, reducing the computational complexity of each operation while maintaining overall reconstruction accuracy through the compressed representation that preserves essential information.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter space by transforming data from high-dimensional original space to low-dimensional compressed space. This parameter transformation reduces the number of parameters the neural network needs to process, thereby reducing computational complexity while maintaining reconstruction accuracy through the preserved data structure in compressed space.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If conventional iterative reconstruction methods are used, then memory requirements are reduced, but reconstruction time increases

Engineering Contradiction:
Improvememory requirementsVSAvoidreconstruction time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent performs preliminary compression of the data into a compressed representation before feeding it to the neural network. This preliminary action reduces the data dimensionality and memory requirements upfront, allowing the subsequent neural network reconstruction to operate more efficiently with less memory while maintaining fast reconstruction speeds.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11823307B2Method for high-dimensional image reconstruction using low-dimensional representations and deep learning
Publication Date: 2023.11.21 THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIV
  • US11823307B2 patent drawing
  • US11823307B2 patent drawing
  • US11823307B2 patent drawing

AI summary

A method for MR imaging includes acquiring with an MR imaging apparatus undersampled k-space imaging data having one or more temporal dimensions and two or more spatial dimensions; transforming the undersampled k-space imaging data to image space data using zero-filled or sliding window reconstruction and sensitivity maps; decomposing the image space data into a compressed representation comprising a product of spatial and temporal parts, where the spatial part comprises spatial basis functions and the temporal part comprises temporal basis functions; processing the spatial basis functions and temporal basis functions to produce reconstructed spatial basis functions and reconstructed temporal basis functions, wherein the processing iteratively applies conjugate gradient and convolutional neural network updates using 2D or 3D spatial and 1D temporal networks; and decompressing the reconstructed spatial basis functions and reconstructed temporal basis functions to produce a reconstructed MRI image having one or more temporal dimensions and two or more spatial dimensions.