MRI Parallel Imaging Hybrid Sampling SNR

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Solution Overview

Problem

Parallel imaging in MRI technologies faces challenges in maintaining image quality due to reduced signal-to-noise ratio (SNR) caused by under-sampling in the K-space, leading to artifacts and decreased resolution.

Innovation Solution

A method and apparatus that combine uniformly under-sampled data with low-frequency fully-sampled data in a hybrid sampling mode to reconstruct images, utilizing a hybrid sampling matrix and sensitivity distribution calculations to improve SNR, by integrating more informative data from the central K-space regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If under-sampling is used in K-space to increase imaging speed, then productivity is improved, but measurement precision deteriorates due to artifacts and reduced SNR

Engineering Contradiction:
Improveimaging speedVSAvoidimage quality and SNR
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the K-space sampling into two distinct parts: low-frequency fully-sampled data and high-frequency uniformly under-sampled data. This segmentation allows the critical low-frequency information (which determines image contrast and SNR) to be fully captured while accepting under-sampling in the high-frequency regions (which contribute less to overall image quality). The segmentation resolves the contradiction by strategically allocating sampling resources.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different sampling strategies to different regions of the K-space based on their local importance. The low-frequency central region receives full sampling to preserve image quality and SNR, while the high-frequency peripheral regions accept under-sampling to increase imaging speed. This local differentiation of sampling quality resolves the contradiction between speed and image quality.

Inventive Principle:
Principle #3Local quality

2Productivity

If under-sampling is used in K-space, then imaging speed is improved, but reliability deteriorates due to image artifacts

Engineering Contradiction:
Improveimaging speedVSAvoidimage accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By segmenting the sampling strategy, the patent ensures that the low-frequency data (which contains reliable structural information) is fully sampled, maintaining image reliability. The high-frequency data is under-sampled but reconstructed using the segmented approach, minimizing artifact introduction while maintaining speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent converts the potential harm of under-sampling artifacts into a benefit by strategically applying under-sampling only where it matters less (high-frequency regions) while maintaining full sampling where it matters most (low-frequency regions). The hybrid approach transforms what would be a harmful uniform under-sampling into a beneficial selective sampling strategy.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS7576539B2Method and apparatus for reconstructing parallel-acquired image
Publication Date: 2009.08.18 SIEMENS HEALTHINEERS AG
  • US7576539B2 patent drawing
  • US7576539B2 patent drawing
  • US7576539B2 patent drawing

AI summary

The invention discloses a method and an apparatus for reconstructing a parallel-acquired image, comprising: generating reconstruction data by combining uniformly under-sampled data and low-frequency fully-sampled data in MRI K-space according to a hybrid sampling mode; calculating the sensitivity distribution of a coil according to said low-frequency fully-sampled data; and reconstructing an image according to the reconstruction data, the coil's sensitivity distribution and the hybrid sampling mode. The signal to noise ratio of the reconstructed image is effectively improved by using the reconstruction data combined with the low-frequency fully-sampled data in reconstructing the image since the low-frequency fully-sampled data contains more useful information.