Respiration-Dependent Heartbeat Model for ECG Triggering

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Solution Overview

Problem

Medical imaging with ECG triggering faces challenges due to the temporal irregularity of heartbeats, particularly caused by respiratory sinus arrhythmia, which affects the accuracy of predicting cardiac phases for optimal image capture.

Innovation Solution

A method that captures both respiration and ECG signals to determine a respiration-dependent heartbeat model, allowing for the specification of reliable trigger time-points for medical imaging, thereby minimizing cardiac movement interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If ECG triggering is used to capture image data at specific cardiac phases, then image quality can be improved by minimizing cardiac movement interference, but the temporal irregularity of heartbeats causes prediction errors in trigger time-points

Engineering Contradiction:
Improveimage qualityVSAvoidtrigger time-point prediction accuracy
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system continuously monitors the ECG signal and uses feedback from actual heartbeat intervals to update and refine the heartbeat model. This allows the trigger time-point predictions to be dynamically adjusted based on observed cardiac rhythm variations, improving both image quality and prediction reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the parameters used for trigger time-point calculation by incorporating multiple ECG intervals and analyzing heartbeat variability patterns. Instead of relying on a fixed or simple average heart rate, the system adapts its prediction parameters based on the actual temporal irregularities observed in the patient's heartbeat, thereby resolving the contradiction between maintaining image quality and achieving reliable triggering.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the heartbeat model assumes regular intervals between heartbeats, then the system complexity remains low, but the accuracy of cardiac phase prediction deteriorates due to respiratory sinus arrhythmia

Engineering Contradiction:
Improveheartbeat model complexityVSAvoidcardiac phase prediction accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The heartbeat model transitions from a static assumption of regular intervals to a dynamic model that adapts to actual heartbeat variability. The system continuously updates its predictions based on observed ECG intervals, allowing it to account for respiratory sinus arrhythmia and other sources of temporal irregularity without requiring overly complex structural changes to the system.

Inventive Principle:
Principle #15Dynamics

3Reliability

If multiple ECG intervals are analyzed to account for heartbeat irregularities, then trigger time-point accuracy improves, but the time required for model determination increases

Engineering Contradiction:
Improvetrigger time-point specification accuracyVSAvoidmodel determination time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary analysis of ECG intervals during a pre-scan or setup phase, establishing the heartbeat model before actual image acquisition begins. This preliminary action allows the system to characterize the patient's specific heartbeat patterns and respiratory influences in advance, so that during the actual imaging process, trigger time-points can be calculated quickly using the pre-established model parameters.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20220054021A1Medical imaging with ECG triggering
Publication Date: 2022.02.24 SIEMENS HEALTHINEERS AG
  • US20220054021A1 patent drawing
  • US20220054021A1 patent drawing
  • US20220054021A1 patent drawing

AI summary

A method is for medical imaging of a patient using a medical imaging system with ECG triggering. In an embodiment, the method includes capturing a respiration signal of the patient including n respiration cycles; concurrently capturing an ECG signal of the patient including m heartbeat intervals; determining a respiration-dependent heartbeat model based upon the n respiration cycles and the m heartbeat intervals; specifying at least one trigger time-point based upon the respiration-dependent heartbeat model; and starting the medical imaging at the specified trigger time-point.