15O-Water PET Quantification of Cerebrovascular Reserve Without Cannulation

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Solution Overview

Problem

The invasive and painful procedure of arterial cannulation for measuring cerebral blood flow (CBF) and cerebrovascular reserve (CVR) using 15O-water PET hampers its clinical application, necessitating a safe, non-invasive method for accurate quantification.

Innovation Solution

A method involving two 15O-water PET scans with controlled bolus injections and acetazolamide administration, eliminating the need for arterial cannulation by describing vasodilation data as a function of baseline data, using a tracer kinetic model to estimate CBF and CVR without an arterial input function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If arterial cannulation is used to obtain arterial input function for quantitative CBF measurement with 15O-water PET, then measurement precision is improved, but patient comfort and ease of operation deteriorate due to invasive and painful procedure

Engineering Contradiction:

Improvequantitative CBF measurement accuracyVSAvoidpatient comfort

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts and removes the arterial cannulation step from the measurement protocol. By using image-derived arterial input function from PET imaging itself rather than invasive arterial sampling, the method eliminates the painful invasive procedure while maintaining quantitative measurement capability through mathematical modeling of the tracer kinetics.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary approach by using the PET imaging data itself as a proxy for the arterial input function. Instead of directly measuring arterial blood radioactivity through cannulation, the method uses the observed tracer distribution in brain tissue and applies kinetic modeling to derive the arterial input function indirectly, serving as a non-invasive mediator between the tracer injection and the CBF quantification.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If arterial cannulation is performed for accurate arterial input function measurement, then measurement precision is improved, but device complexity and procedural complexity increase

Engineering Contradiction:

Improvearterial input function accuracyVSAvoidprocedural complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent removes the complex arterial cannulation procedure and associated monitoring equipment from the measurement system. The arterial input function is derived entirely from the PET imaging data and kinetic modeling, eliminating the need for invasive catheters, blood sampling systems, and related complex apparatus.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical invasive system of arterial cannulation and physical blood sampling with a computational approach. Kinetic modeling algorithms process the PET imaging data to mathematically derive the arterial input function, substituting mechanical intrusion with information processing and mathematical analysis.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If standard acetazolamide challenge test with single 1000 mg dose is used, then diagnostic purpose is fulfilled, but therapeutic flexibility is reduced for patients requiring repeated dosing

Engineering Contradiction:

ImproveCVR assessment accuracyVSAvoiddosing flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static single-dose protocol into a dynamic, adaptable dosing regimen. The acetazolamide administration is customized based on individual patient needs, allowing adjustment of dose amount and frequency. This dynamic approach enables the same diagnostic methodology to serve both diagnostic CVR assessment and therapeutic purposes with flexible dosing schedules.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent makes the acetazolamide challenge methodology universally applicable for multiple purposes. By establishing a standardized yet flexible protocol framework, the same PET measurement approach can be used for both diagnostic CVR evaluation and monitoring therapeutic response, accommodating various dosing scenarios from single diagnostic doses to repeated therapeutic administrations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables non-invasive, quantitative measurement of CBF and CVR, overcoming the limitations of invasive methods and allowing widespread clinical use of 15O-water PET.

Implementation Method 1

15O-water positron emission tomography (PET)

Methodology Applied

Scientific EffectRadioactive decay: Radioactive Decay

Implementation Method 2

15O-water positron emission tomography (PET)

Methodology Applied

Scientific EffectPositron emission: Radioactive Decay

Implementation Method 3

Acetazolamide (an inhibitor of carbonic anhydrase), which causes an acidosis and a significant increase in brain perfusion due to dilatation of intracranial arteries

Methodology Applied

Scientific EffectVasodilation:

Data Source

PatentUS20250366801A1Estimation of cerebrovascular reserve

Publication Date: 2025.12.04 MEDTRACE AS

AI summary

A method for non-invasive quantitative measurement of cerebrovascular reserve (CVR) and cerebral blood flow (CBF) with 15O-water positron emission tomography (PET) in a human.