Dynamic CT Perfusion Phase Selection via Projection Intensity Comparison

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Solution Overview

Problem

Conventional CT perfusion studies require a large number of scans, leading to high X-ray doses for patients, and existing methods for estimating perfusion phases are often inaccurate due to patient variability.

Innovation Solution

An imaging system and method that uses a CT acquisition unit and processing unit to collect and compare sample projections to reference projections, dynamically triggering imaging scans based on intensity changes to reduce the number of scans and improve phase estimation accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large number of scans are acquired to capture perfusion phases, then the accuracy of perfusion imaging is improved, but the X-ray radiation dose to the patient increases significantly

Engineering Contradiction:

Improveperfusion imaging accuracyVSAvoidX-ray radiation dose

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary actions by acquiring reference projections and sample projections at specific time points before the actual imaging scans. These preliminary projections are used to estimate contrast uptake and washout phases, allowing the system to trigger full imaging scans only when needed, thereby reducing the total number of scans and radiation dose while maintaining perfusion imaging accuracy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the sample projections and intensity comparisons to dynamically adjust and trigger full imaging scans. By continuously monitoring contrast enhancement and comparing sample projections against reference projections, the system receives feedback about the current perfusion phase and only initiates full scans when the contrast phases are appropriately captured, optimizing the balance between imaging accuracy and radiation dose reduction

Inventive Principle:

Principle #23Feedback

2Device complexity

If fixed sampling intervals are used for perfusion studies, then the imaging protocol is simplified, but the phase estimation accuracy deteriorates due to patient variability

Engineering Contradiction:

Improveimaging protocol complexityVSAvoidphase estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system transitions from fixed sampling intervals to dynamic sampling by continuously monitoring contrast enhancement in real-time. The sampling frequency and scan triggering are dynamically adjusted based on the actual perfusion phase detected through sample projection comparisons, allowing the system to adapt to individual patient variability while maintaining protocol simplicity through automated phase detection

Inventive Principle:

Principle #15Dynamics

3Loss of information

If traditional CT perfusion protocols with multiple sequential scans are used, then comprehensive perfusion information is obtained, but the examination time and radiation dose increase

Engineering Contradiction:

Improveperfusion information completenessVSAvoidexamination time

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The system extracts essential perfusion information from the time-domain signal by identifying and isolating the critical contrast uptake and washout phases. Instead of acquiring data at all times, the system extracts only the meaningful perfusion information by triggering scans at specific phases detected through sample projection analysis, thereby reducing examination time and radiation dose while maintaining information completeness

Inventive Principle:

Principle #2Taking out (Extraction)

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 reduces the number of scans and radiation dose in perfusion studies while providing more accurate timing for imaging scans and enabling the determination of cardiac output during CT perfusion studies.

Implementation Method 1

an X-ray source may be rotated around an object to obtain imaging information. X-rays from the source attenuated by the object may be collected or detected by a detector

Methodology Applied

Scientific EffectX-ray attenuation: Absorption (EM radiation)

Data Source

PatentUS9517042B2Systems and methods for imaging phase selection for computed tomography imaging

Publication Date: 2016.12.13 GE PRECISION HEALTHCARE LLC

AI summary

An imaging system includes a computed tomography (CT) acquisition unit and a processing unit. The CT acquisition unit includes an X-ray source and a CT detector configured to collect CT imaging data of an object to be imaged. The processing unit includes at least one processor operably coupled to the CT acquisition unit. The processing unit is configured to control the CT acquisition unit to collect at least one sample projection during rotation of the CT acquisition unit about the object to be imaged, compare an intensity of the at least one sample projection to an intensity of a reference projection, select a time to perform an imaging scan based on the comparison of the intensity of the at least one sample projection to the intensity of the reference projection, and control the CT acquisition unit to perform the imaging scan.