Ultrasound Localization Transducer Array for Needle Positioning
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Solution Overview
Problem
Current methods for accurately and consistently locating medical instruments during ultrasound imaging are inadequate, leading to increased patient discomfort, procedure duration, and risks due to uncertainty in instrument tip position, especially when the instrument is outside the ultrasound scan plane or has low echogenicity.
Innovation Solution
An ultrasound system with a distinct set of imaging and localization transducer elements, where the localization transmissions extend beyond the image scan plane, and a medical instrument with an optical fiber and transducer at the tip to detect ultrasound and optical signals, allowing for real-time determination of the instrument's position relative to the ultrasound probe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If echogenic needles with surface modifications are used to increase visibility in ultrasound images, then the needle becomes more prominent in the ultrasound image, but the needle may still be invisible when outside the ultrasound imaging plane and large artifacts are introduced that risk obscuring anatomical detail
Solution Approach 1:
The patent introduces an intermediary localization system consisting of separate localization transducer elements and a localization console that processes time-of-flight measurements. This intermediary system mediates between the ultrasound imaging system and the needle, providing accurate positional information without requiring the needle to be visible in the ultrasound image, thereby avoiding the artifact problem while maintaining visibility.
Solution Approach 2:
The patent replaces the mechanical/physical modification approach (echogenic coatings and surface indentations) with an acoustic field-based localization approach using time-of-flight measurements. Instead of modifying the needle's physical properties to reflect ultrasound, the system uses acoustic wave propagation timing to determine position, eliminating the need for echogenic modifications and their associated artifact problems.
2Reliability
If the needle is secured in a mechanical needle guide to maintain trajectory, then the needle is maintained close to the scan plane, but approaches to the target cannot be changed without complete withdrawal and reinsertion of the needle
Solution Approach 1:
The patent implements a dynamic localization system that continuously tracks needle position in real-time using time-of-flight measurements from multiple localization transducer elements. This dynamic feedback enables the operator to adjust the needle trajectory flexibly during the procedure while maintaining reliable positional awareness, eliminating the need for rigid mechanical guides that prevent mid-procedure adjustments.
Solution Approach 2:
The patent incorporates a feedback mechanism where the localization console processes time-of-flight measurements and provides real-time positional information to the operator. This feedback loop enables continuous monitoring and adjustment of needle trajectory, allowing versatility in approach changes while maintaining reliability through constant positional awareness, without requiring mechanical constraints.
3Measurement precision
If ultrasound imaging transmissions are focused into an image scan plane, then a two-dimensional anatomical image is generated, but the medical instrument cannot be located when it is outside the scan plane
Solution Approach 1:
The patent segments the ultrasound transducer array into two distinct functional sets: imaging transducer elements that focus transmissions into the scan plane for high-resolution anatomical imaging, and separate localization transducer elements that detect transmissions extending beyond the scan plane. This segmentation allows simultaneous optimization of image resolution and three-dimensional instrument localization without compromise.
Solution Approach 2:
The patent extends the localization function into a third dimension by using localization transducer elements spaced in a direction perpendicular to the scan plane. This dimensional extension enables detection of instrument positions outside the two-dimensional scan plane through time-of-flight measurements, providing three-dimensional localization capability while maintaining the integrity of the two-dimensional anatomical imaging function.
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 accurate and real-time localization of medical instruments within the body, reducing procedure time and patient discomfort by providing precise positioning of instruments, even when they are outside the ultrasound scan plane, and improving visibility and safety by integrating optical and ultrasound detection.
Implementation Method 1
A typical ultrasound system can utilize a transducer array to deliver acoustic pulses into the body and to temporally resolve reflected acoustic pulses
Implementation Method 2
at least one optical fiber, running along the elongated structure, for transmitting an interrogation light signal to the distal tip and for transmitting a data signal back from the distal tip or side aperture
Implementation Method 3
a transducer located at the distal tip for detecting ultrasound transmissions incident upon the distal tip. The transducer includes at least one surface to reflect the interrogation light signal from the optical fiber with an intensity and/or phase that varies according to the incident ultrasound transmissions
Data Source
AI summary
An ultrasound system comprises an ultrasound unit including: an ultrasound probe including a first set of imaging transducer elements and a second set of localisation transducer elements. The first set of imaging transducer elements are configured to: (i) produce ultrasound imaging transmissions into the human body, wherein the ultrasound imaging transmissions are focussed into an image scan plane, and (ii) receive reflections of the ultrasound imaging transmissions for generating a two-dimensional anatomical image corresponding to the image scan plane. The second set of localisation transducer elements are configured to produce ultrasound localisation transmissions into the human body for locating the medical instrument with respect to the anatomical image, wherein the ultrasound localisation transmissions extend outside the image scan plane.