Cannula Tip Localization Using Detachable Ultrasound Transmitters

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Solution Overview

Problem

Existing methods for determining the position of a cannula tip inside a body, such as the 'OnVision' system, require integration into the ultrasound imaging system, limiting their universality and potentially interfering with imaging procedures.

Innovation Solution

A method and system that utilize detachable ultrasound position transmitters attached to the ultrasound transducer, using signal propagation times to determine the cannula tip's position without integrating into the imaging system, allowing for precise position determination using geometric relationships and multiple sensors to avoid interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the ultrasound position transmitters are integrated into the ultrasound imaging system, then the position determination can be performed, but the universality is limited and interference with imaging procedures may occur

Engineering Contradiction:
ImproveuniversalityVSAvoidintegration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system is divided into separate functional modules: the ultrasound imaging system and the position determination system operate independently. The position transmitters are not integrated into the ultrasound transducer but function as separate components that can be used with any ultrasound system, thereby achieving universality without integration complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The position determination system uses ultrasound position signals at a different frequency than the imaging ultrasound signals, acting as an intermediary that does not interfere with the primary imaging function. This frequency separation allows both systems to operate simultaneously without mutual interference

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the sensor is placed as close as possible to the cannula tip, then the position determination accuracy is improved, but the cannula tip's function may be impaired

Engineering Contradiction:
Improveposition determination accuracyVSAvoidcannula tip function impairment
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The solution moves the sensor away from the cannula tip along the longitudinal axis, utilizing the known axial distance as an additional dimensional parameter. This allows the sensor to be positioned at a safe distance while the evaluation unit calculates the tip position by combining the sensor position with the known axial offset, thereby maintaining accuracy without impairing tip function

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If multiple sensors are used for position determination, then the accuracy and orientation determination are improved, but the device complexity increases

Engineering Contradiction:
Improveposition and orientation determination accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple sensors serve dual purposes: they determine both the position and orientation of the cannula, and they provide redundancy for improved measurement accuracy. The evaluation unit processes signals from all sensors to calculate both positional coordinates and angular orientation, maximizing the utility of each additional sensor while maintaining a relatively simple overall system architecture

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 universal applicability and precise, interference-free determination of cannula tip position, enhancing patient safety and versatility.

Implementation Method 1

coupling several ultrasound position signals into the body, wherein the ultrasound position signals are coupled in by means of the several ultrasound position transmitters

Methodology Applied
Scientific EffectUltrasound: Ultrasound

Implementation Method 2

receiving the ultrasound position signals, wherein the ultrasound position signals are received by means of a sensor attached to a cannula

Methodology Applied
Scientific EffectUltrasound detection: Ultrasound

Implementation Method 3

determining the signal transit times of the ultrasound position signals, wherein the signal transit times are determined by means of an evaluation unit connected to the sensor and the transmitter

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP4684737A1Method and system for determining a position of a cannula tip
Publication Date: 2026.01.28 B BRAUN MELSUNGEN AG
  • EP4684737A1 patent drawingFigure 1
  • EP4684737A1 patent drawingFigure 2
  • EP4684737A1 patent drawingFigure 3~4

AI summary

The invention relates to a method for determining the position of a cannula tip inside a body, comprising the steps of: providing an ultrasound transducer of an ultrasound imaging system; providing a transmitter comprising several ultrasound position transmitters and at least one mounting section; attaching the transmitter to the ultrasound transducer, wherein the transmitter is detachably attached to the ultrasound transducer by means of the mounting section and is fixed to the ultrasound transducer in a defined relative position to the ultrasound transducer; coupling several ultrasound position signals into the body, wherein the ultrasound position signals are coupled in by means of the several ultrasound position transmitters; receiving the ultrasound position signals, wherein the ultrasound position signals are received by means of a sensor attached to a cannula located in the body and arranged at a known axial distance from its cannula tip;Determining the signal transit times of the ultrasound position signals, wherein the signal transit times are determined by means of an evaluation unit connected to the sensor and the transmitter; determining the position of the cannula tip in relation to the ultrasound transducer, wherein the position is determined by means of the evaluation unit as a function of the signal transit times, the relative position of the transmitter to the ultrasound transducer and the axial distance of the sensor from the cannula tip. The invention also relates to a medical system for determining the position of a cannula tip.