Brain Atrophy Rate Estimation Using Reference Data Models

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Solution Overview

Problem

Current techniques for measuring brain atrophy rates are prone to high measurement noise and error, especially when using MRI, due to variations in imaging hardware and protocols, making it difficult to detect subtle changes in brain volume over short periods.

Innovation Solution

A method and system that use a reference data model based on long-term measurements from healthy subjects to reduce measurement noise, allowing for reliable estimation of brain volume change rates from a small number of scans taken over a short period, typically 12 months.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If measurements are taken over a short period to enable timely detection, then productivity is improved, but measurement precision deteriorates due to high noise levels

Engineering Contradiction:
Improvedetection speedVSAvoidatrophy rate measurement precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The method performs preliminary actions by collecting longitudinal measurements from healthy control subjects to establish a reference model before measuring the patient. This reference model, built from multiple time points, captures the natural variability and noise patterns, enabling subsequent short-term patient measurements to be interpreted more accurately by comparing against the established baseline of normal variation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The reference model derived from healthy control data acts as an intermediary between the noisy short-term patient measurements and the true atrophy rate. This intermediary model provides context by characterizing normal measurement variability, allowing the system to distinguish between noise and actual pathological change even when measurement intervals are short.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple measurements are taken over a long period to improve measurement precision, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improveatrophy rate measurement precisionVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The reference model is built in advance from longitudinal healthy control data, storing the characteristics of normal variation. When a patient is measured, this pre-established model allows accurate interpretation of short-term changes without requiring lengthy measurement periods, thus reducing time loss while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The reference model creates a copy or representation of normal healthy brain atrophy patterns from longitudinal healthy control data. This copied model can be repeatedly applied to patient data without requiring repeated long-term studies, enabling precise measurements in short timeframes by comparing patient deviations from the established normal pattern.

Inventive Principle:
Principle #26Copying

3Ease of operation

If a simple additive correction is applied to MRI protocols to improve ease of operation, then ease of operation is improved, but measurement precision deteriorates due to inability to capture complex protocol variations

Engineering Contradiction:
Improveprotocol correction simplicityVSAvoidatrophy rate measurement precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The method transforms the approach from correcting individual protocol parameters to changing the fundamental parameter being measured - instead of attempting to correct each acquisition parameter, the system measures the composite effect of all protocol variations through the reference model, which captures the net impact on atrophy rate estimation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The reference model serves as an intermediary that absorbs and accounts for complex protocol variations without requiring explicit correction of each parameter. By modeling normal variation including protocol effects in healthy controls, the system indirectly compensates for protocol differences when comparing to patient data, maintaining precision without simple additive corrections.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3725224B1Method and system for determining the rate of change of a quantitative parameter
Publication Date: 2025.05.28 SIEMENS HEALTHINEERS AG
  • EP3725224B1 patent drawingFigure 1
  • EP3725224B1 patent drawingFigure 2
  • EP3725224B1 patent drawing

AI summary

The present invention concerns a method (100) and a system (200) for determining a regularized estimate of a change rate of a quantitative parameter measured for a biological object of a new subject, the method comprising: - measuring (105) said quantitative parameter at a first time and at a second time within a short period of time; - determining (108) an approximative change rate r of the measured quantitative parameter; the method being characterized in that it automatically determines (109) the regularized estimate rreg from rreg=1−λr+λm wherein m is a mean value for said change rate of the quantitative parameter obtained by applying a reference data model to values of said quantitative parameters obtained by measurements of the latter for said biological object of healthy subjects, wherein for each healthy subject, values of the quantitative parameter have been obtained by making a series of said measurements over a long period of time with respect to said short period of time; and λ is computed analytically using an estimate of the variance of the values of the quantitative parameters measured for said healthy subjects.