X-ray CT Image Deterioration Area Discrimination and Masking

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Solution Overview

Problem

In X-ray CT systems with 64 or more segments, the cone angle leads to insufficient projection data, resulting in deteriorating areas on CT images that are difficult to distinguish from non-deteriorating areas, making it challenging for operators to determine the scan area coverage during inspections.

Innovation Solution

An image display apparatus and X-ray CT apparatus that utilize a mechanism to generate and display maps of deteriorating and non-deteriorating areas, allowing for the discrimination and masking of deteriorating areas through image processing, enabling accurate scan area determination and improved image interpretation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multi-arrayed detecting elements (64 or more segments) are used along the body axis direction, then the field of view and coverage are improved, but deteriorating areas appear on CT images due to insufficient projection data from the cone angle

Engineering Contradiction:
Improvefield of viewVSAvoidimage quality
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The image is segmented into deteriorating areas and non-deteriorating areas based on projection data sufficiency. This allows differential processing where only the reliable non-deteriorating areas are used for diagnostic purposes, while deteriorating areas are excluded or masked.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A map indicating the distribution of deteriorating and non-deteriorating areas is introduced as an intermediary tool. This map guides the masking process and helps operators understand which areas are reliable for diagnosis, bridging the gap between the raw image data and diagnostic interpretation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the deteriorating area is masked on CT images, then image interpretation is improved, but operators cannot identify the range to be masked

Engineering Contradiction:
Improveimage interpretationVSAvoidmasking operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system provides visual feedback by displaying a map that shows where deteriorating areas are located before masking is applied. This feedback mechanism guides operators in setting the masking range accurately, ensuring they mask the correct areas without guessing or trial-and-error.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The map of deteriorating and non-deteriorating areas is generated and displayed before the masking operation. This preliminary visualization allows operators to plan and set the masking range in advance, making the subsequent masking operation straightforward and accurate.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If the deteriorating area is not distinguished on displaying, then the CT image appears uniform, but operators fail to determine whether the scan area covers the predetermined site

Engineering Contradiction:
Improvedisplay simplicityVSAvoidscan area coverage information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The information about area quality is added in a new dimension through a separate map overlay, rather than trying to encode it in the grayscale of the CT image itself. This allows the CT image to remain visually simple while the map provides additional dimensional information about reliability and coverage.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The map uses different visual representations (such as shading or coloring) to distinguish between deteriorating and non-deteriorating areas. This visual differentiation allows operators to quickly assess scan coverage and image reliability without complicating the underlying CT image display.

Inventive Principle:
Principle #32Color changes

Data Source

PatentEP1825811B1Image display apparatus and x-ray computed tomography apparatus
Publication Date: 2015.08.26 KK TOSHIBA
  • EP1825811B1 patent drawingFigure 1
  • EP1825811B1 patent drawingFigure 2
  • EP1825811B1 patent drawingFigure 3

AI summary

An X-ray computed tomography apparatus has an area arithmetic unit and an image processing unit. The area arithmetic unit obtains information with respect to a position of a deteriorating area appeared around an end on an acquisition range of a projection data under an influence of a cone angle. The image processing unit performs an image processing for a CT image to be discriminable the deteriorating area from an area other than the deteriorating area.