Dynamic MR Image Reconstruction Using Static Region Segmentation
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Solution Overview
Problem
Dynamic magnetic resonance imaging faces challenges in achieving high temporal resolution while minimizing streaking artifacts, particularly in rapidly varying procedures, due to the need for underscanning which results in artifacts from non-dynamic regions like patient arms.
Innovation Solution
The method involves dividing the examination region into dynamic and non-dynamic areas, reconstructing a static image data record from all magnetic resonance data, identifying and eliminating image data from non-dynamic regions through inverse transformation, and using this corrected data for artifact-reduced reconstruction of dynamic image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the number of radial k-space lines is reduced to achieve high temporal resolution, then temporal resolution is improved, but streaking artifacts increase in magnitude
Solution Approach 1:
The examination region is segmented into a dynamic region (where the dynamic procedure occurs) and a non-dynamic region (peripheral regions causing artifacts). By separately processing these regions and applying artifact correction only to the dynamic region, the method maintains high temporal resolution while reducing streaking artifacts in the diagnostically relevant area.
Solution Approach 2:
The artifact correction is applied locally to the dynamic region rather than uniformly across the entire image. This allows temporal resolution to be maintained in the dynamic region while using additional k-space lines only where needed for artifact suppression in peripheral non-dynamic regions.
2Object-affected harmful factors
If more radial k-space lines are used for reconstruction, then streaking artifacts are reduced, but temporal resolution deteriorates
Solution Approach 1:
The image reconstruction process is segmented into two passes: first reconstructing a static image using all available k-space lines for comprehensive artifact suppression, then using this static image to guide selective artifact correction in the dynamic region. This allows artifact reduction without requiring all k-space lines for every dynamic frame.
Solution Approach 2:
A static image is reconstructed preliminarily from all k-space lines before dynamic image reconstruction. This preliminary static image contains minimal artifacts and is used to identify and correct artifacts in the dynamic region, enabling subsequent dynamic reconstructions to use fewer k-space lines while maintaining artifact suppression.
3Productivity
If radial scanning is used to enable continuous recording, then temporal resolution is improved, but underscanning artifacts occur in rapidly variable portions
Solution Approach 1:
A complete static reconstruction is performed preliminarily using all radially scanned k-space lines. This preliminary reconstruction provides a reference image with minimal underscanning artifacts, which is then used to guide artifact correction in the dynamic region, allowing rapid continuous recording while maintaining image quality.
Solution Approach 2:
The static image reconstruction serves as an intermediary between the radially scanned k-space data and the final dynamic images. It mediates the underscanning artifacts by providing a reference for artifact identification and correction, enabling the dynamic images to achieve both high temporal resolution and acceptable image quality.
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 significantly reduces artifacts and stabilizes measurement results by removing data from non-dynamic regions, allowing for high-quality, artifact-free dynamic image reconstruction with improved temporal resolution.
Implementation Method 1
magnetic resonance data of the examination region are continuously recorded by radial scanning along radial k-space lines
Implementation Method 2
magnetic resonance images are reconstructed from at least some of the magnetic resonance data allocated to k-space lines recorded during the time segment
Data Source
AI summary
In a method and apparatus for acquiring and reconstructing a four-dimensional dynamic magnetic resonance (MR) image data record, MR data are continuously acquired by radial scanning of an examination region along radial k-space lines, and a dynamic region of the examination region, in which said dynamic procedure is relevant, is determined, as well as a non-dynamic region, which is not relevant to the dynamic procedure. Static image data are reconstructed from all of the acquired MR data, and image data therein originating from the non-dynamic region are marked and are then not used for reconstructing a dynamic image data record for the dynamic region.