MRI UTE Imaging Mask Processing for Artifact Removal
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Solution Overview
Problem
Ultrashort TE (UTE) imaging in MRI apparatuses struggles to isolate MR signals from human bodies while excluding signals from non-living substances like coil devices and beds, due to the short echo time setting which leads to undesired components being included in the images.
Innovation Solution
The MRI apparatus employs processing circuitry to generate UTE and non-UTE images, and uses a mask image processed from the non-UTE image to remove or reduce undesired signals from the UTE image, by applying binarization, closing, and boundary identification processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If echo time TE is set very short in UTE imaging to acquire MR signals from tissues with very short transverse relaxation time (bones, lungs), then the ability to depict bone region and lung region is improved, but undesired components such as coil device and bed are also included in the image
Solution Approach 1:
The patent segments the imaging process into two distinct phases: UTE imaging to capture signals from short-T2 tissues (bones, lungs) and non-UTE imaging to capture signals from longer-T2 tissues (soft tissues). By separating the acquisition of different tissue types into different imaging sequences, the method enables selective processing where mask images from non-UTE can suppress unwanted coil and bed signals while preserving desired anatomical structures.
Solution Approach 2:
The patent extracts and removes undesired components (coil device and bed signals) from the UTE image by using mask images generated from non-UTE imaging. The mask processing selectively identifies and eliminates signals from non-living substances while preserving signals from the human body, effectively extracting only the desired anatomical information from the mixed UTE signal.
2Object-affected harmful factors
If echo time TE is set to conventional values (several milliseconds) in conventional imaging methods, then undesired components from coil device and bed are reduced, but MR signals from tissues with very short transverse relaxation time decay before data acquisition
Solution Approach 1:
The patent segments the imaging task into two specialized sequences: UTE for capturing short-T2 tissue signals before decay, and non-UTE for capturing longer-T2 tissue signals and generating masks. This segmentation allows each sequence to be optimized for its specific purpose, with UTE using very short TE to capture bone and lung signals, while non-UTE uses conventional TE to generate clean mask images for suppressing unwanted artifacts.
Solution Approach 2:
The patent performs preliminary action by acquiring non-UTE images before or alongside UTE images to generate mask images that will be used for suppressing unwanted components. The mask images are prepared in advance from the non-UTE sequence, which has sufficient signal from both desired and undesired components, enabling subsequent selective suppression in the UTE image reconstruction process.
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 effectively removes or reduces undesired components from UTE images, ensuring that only the desired components of the human body are depicted, improving image clarity and accuracy.
Implementation Method 1
An MRI apparatus is an imaging apparatus that magnetically excites nuclear spin of an object placed in a static magnetic field by applying a radio frequency (RF) pulse having the Larmor frequency and reconstructs an image on the basis of magnetic resonance (MR) signals emitted from the object due to the excitation
Data Source
AI summary
In one embodiment, an MRI apparatus includes a memory storing a predetermined program and processing circuitry. The processing circuitry configured, by executing the predetermined program, to generate a first image based on first data acquired from an object with Ultrashort TE (UTE), generate a second image based on second data acquired from the object with non-UTE, generate a mask image from the second image, and perform mask processing, by using the mask image, to remove or reduce an undesired signal around the object depicted in the first image.