MRI Noise Suppression via Direct Sampling AD Conversion

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Solution Overview

Problem

In MRI apparatuses, the installation of the reception system for MR signals by direct sampling poses challenges due to space constraints in imaging and machine rooms, particularly when upgrading from low to high magnetic field types, necessitating the placement of at least part of the reception system within the imaging room while managing digital noise generation.

Innovation Solution

The MRI apparatus incorporates a data acquisition unit with an AD converter that converts analog MR signals into digital signals inside the imaging room, accompanied by a noise suppression part that includes an encoding and decoding circuit to mitigate digital noise through bit inversion and randomization, ensuring effective noise suppression before down conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the reception system is placed in the machine room magnetically shielded from the imaging room, then magnetic field interference is avoided, but space constraints in the imaging room prevent this placement when upgrading from low to high magnetic field types

Engineering Contradiction:

Improvemagnetic field interferenceVSAvoidimaging room space

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The reception system is divided into two parts: the AD converter is placed in the imaging room for space-efficient direct sampling, while the down conversion and other signal processing functions are separated and placed in the machine room. This segmentation allows the system to leverage the advantages of both locations without requiring the entire reception system to be in one location.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a signal transmission mechanism as an intermediary to connect the AD converter in the imaging room with the down conversion system in the machine room. This intermediary allows the analog signal to be transmitted from the imaging room to the machine room for further processing, resolving the space constraint issue while maintaining magnetic shielding benefits.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If direct sampling with AD conversion is performed inside the imaging room, then space is saved and system flexibility is improved, but digital noise is generated during the conversion process

Engineering Contradiction:

Improveimaging room spaceVSAvoiddigital noise

Core Design Contradiction:

Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the noise suppression function from the main signal processing chain by introducing a dedicated noise suppression part that operates independently. This noise suppression part processes the digital signal generated during AD conversion to remove unwanted noise, allowing the AD converter to be placed in the imaging room while mitigating the digital noise issue through separate processing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful digital noise generated during AD conversion into a manageable signal by applying noise suppression techniques. The noise suppression part processes the digital signal to eliminate artifacts, effectively transforming the harmful noise into a controlled parameter that can be removed through signal processing.

Inventive Principle:

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

3Adaptability or versatility

If the reception system is placed in the imaging room to accommodate space constraints, then installation flexibility is improved, but noise arising from AD conversion contaminates the MR signals

Engineering Contradiction:

Improveinstallation flexibilityVSAvoidsignal quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The reception system is segmented into an AD converter placed in the imaging room for installation flexibility and a noise suppression part placed to process the digital signal. This segmentation allows the system to be installed in space-constrained imaging rooms while maintaining signal quality through separate noise suppression processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The noise suppression part acts as an intermediary between the AD converter and the final signal processing stages. It receives the digital signal from the AD converter, suppresses noise artifacts, and provides cleaned signal data to subsequent processing stages, thereby maintaining signal quality despite the constrained installation environment.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9910112B2Noise suppression for MRI signals directly sampled and digitized in imaging room

Publication Date: 2018.03.06 TOSHIBA MEDICAL SYST CORP

AI summary

According to one embodiment, an MRI apparatus includes a data acquisition unit and an image generation unit. The data acquisition unit acquires an analog MR signal from an object and converts the analog MR signal into a digital MR signal. The image generation unit generates MR image data based on the digital MR signal. The data acquisition unit includes an AD converter, a signal processing part and a noise suppression part. The AD converter converts the analog MR signal, before a down conversion, into the digital MR signal, inside an imaging room. The signal processing part performs signal processing of the digital MR signal, inside the imaging room or outside the imaging room. The noise suppression part suppresses a noise arising caused by a conversion from the analog MR signal, before the down conversion, into the digital MR signal.