MRI Coil Sensitivity Map Phase Shift Artifact Reduction

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Solution Overview

Problem

Magnetic resonance imaging (MRI) apparatuses face artifacts in interpolated images due to non-smooth phase changes when reconstructing images from undersampled data, leading to poor image quality.

Innovation Solution

The MRI apparatus acquires multiple coil sensitivity maps with different phase shifts to generate images that reduce artifacts by interpolating and combining them statistically, resulting in a final image with improved resolution and reduced computational costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If image reconstruction is performed using estimated coil sensitivity map from undersampled data, then imaging time is shortened, but artifacts occur in largely phase changing portions of the interpolated image

Engineering Contradiction:

Improveimaging timeVSAvoidimage quality

Core Design Contradiction:

Loss of timeVSManufacturing precision

Solution Approach 1:

The image is divided into multiple regions based on phase change characteristics. Regions with large phase changes are identified and processed differently from regions with small phase changes, allowing artifact reduction in critical areas while maintaining overall imaging efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different interpolation methods or parameters are applied to different regions of the image based on local phase change characteristics. Regions with large phase changes receive specialized processing to minimize artifacts, while other regions use standard interpolation methods

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If multiple coil sensitivity maps with different phase shifts are acquired and combined, then artifacts from steep phase changes are reduced, but computational costs increase

Engineering Contradiction:

Improveimage qualityVSAvoidcomputational costs

Core Design Contradiction:

Manufacturing precisionVSPower

Solution Approach 1:

Instead of acquiring multiple full coil sensitivity maps, the method acquires additional phase-shifted sensitivity information only in regions where it is most needed (largely phase changing portions), reducing overall computational burden while still achieving artifact reduction where required

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

Phase shift compensation techniques are used as an intermediary method to reduce artifacts without requiring full acquisition and processing of multiple complete coil sensitivity maps, thereby lowering computational costs

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12019132B2Magnetic resonance imaging apparatus, image generation method, and computer-readable nonvolatile storage medium storing image generation program

Publication Date: 2024.06.25 CANON MEDICAL SYST CORP

AI summary

A magnetic resonance imaging apparatus includes processing circuitry. The processing circuitry is configured to acquire a first coil sensitivity map and a second coil sensitivity map for a plurality of coils, the second coil sensitivity map being different in phase from the first coil sensitivity map; generate a first image based on the first coil sensitivity map and magnetic resonance data related to the plurality of coils; generate a second image based on the first coil sensitivity map, the second coil sensitivity map, and the first image; and generate a final image from the first image and the second image.