CT Table Deflection Compensation in Helical Scanning

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In computed tomography (CT) imaging systems, table deflection during helical scans causes artifacts in reconstructed images due to mechanical instability and imperfect alignment, affecting clinical diagnosis.

Innovation Solution

Estimating and compensating for table deflection by modeling it as a vertical movement using linear or quadratic displacement, and applying vertical offsets to the gantry position or reconstruction plane during image reconstruction, which can be done through various methods including half-scan reconstructions, direct measurement using sensors, or rebining projection data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If table deflection is not compensated during helical CT scanning, then the system operates with simple reconstruction procedures, but image quality deteriorates due to artifacts caused by table motion

Engineering Contradiction:

Improveimage qualityVSAvoidreconstruction procedure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by estimating table deflection parameters before performing the final image reconstruction. The system first estimates deflection parameters from the projection data, then uses these parameters to adjust the reconstruction process, thereby eliminating artifacts caused by table motion during helical scanning

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements parameter changes by modifying the reconstruction parameters based on estimated table deflection. The system adjusts the reconstruction process using deflection parameters (such as vertical offsets) to compensate for table motion, thereby improving image quality without requiring complex hardware modifications

Inventive Principle:

Principle #35Parameter changes

2Reliability

If table deflection compensation is applied during reconstruction, then image artifacts are reduced, but computational complexity increases

Engineering Contradiction:

Improvediagnostic accuracyVSAvoidreconstruction algorithm complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary estimation of table deflection parameters from the acquired projection data before executing the compensated reconstruction algorithm. This preliminary step enables the main reconstruction process to use pre-calculated correction parameters, reducing the computational burden during the actual reconstruction phase

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary step where table deflection parameters are estimated and serve as mediators between the raw projection data and the final reconstructed images. These intermediate parameters facilitate the compensation process by providing correction values that simplify the overall computational workflow

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9538974B2Methods and systems for correcting table deflection

Publication Date: 2017.01.10 GENERAL ELECTRIC CO

AI summary

Various methods and systems are provided for estimating and compensating for table deflection in reconstructed images. In one embodiment, a method for computed tomography (CT) imaging comprises reconstructing images from data acquired during a helical CT scan where table deflection parameters are estimated and the reconstruction is adjusted based on the table deflection parameters. In this way, images may be reconstructed without artifacts caused by table deflection.