IVUS Transducer Array for Resolution and Penetration Tradeoff
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Solution Overview
Problem
Intravascular ultrasound (IVUS) devices face a tradeoff between spatial resolution and depth of penetration due to the use of ultrasound transducers operating at a single center frequency, and they are inadequate for Doppler color flow imaging when blood flow is perpendicular to the imaging plane.
Innovation Solution
An IVUS imaging device with a flexible elongate member featuring an imaging assembly that includes multiple ultrasound transducers operating at different center frequencies, allowing for improved spatial resolution and depth penetration, and enabling color-Doppler imaging by positioning and tilting transducers to generate non-zero Doppler shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an ultrasound transducer operates at a higher center frequency, then spatial resolution is improved, but depth of penetration deteriorates
Solution Approach 1:
The imaging assembly is segmented into multiple ultrasound transducers, each operating at different center frequencies. This allows the system to simultaneously perform high-resolution imaging with higher frequency transducers and deep penetration imaging with lower frequency transducers, resolving the contradiction between resolution and penetration depth.
Solution Approach 2:
The imaging assembly is designed with multi-functionality by incorporating transducers with different operating frequencies, enabling the single device to perform both high-resolution superficial imaging and deep tissue penetration imaging, thus universally addressing both requirements that were previously mutually exclusive.
2Measurement precision
If the ultrasound frequency is increased to improve resolution, then spatial resolution is improved, but contrast between blood echoes and vessel wall tissue echoes deteriorates
Solution Approach 1:
The system segments the imaging function across multiple transducers operating at different frequencies. Lower frequency transducers provide better blood-tissue contrast while higher frequency transducers provide higher spatial resolution, allowing the system to lose less information by combining complementary frequency data.
3Device complexity
If a single center frequency is used, then device complexity is reduced, but imaging versatility deteriorates
Solution Approach 1:
The imaging assembly achieves universality by integrating multiple transducers with different center frequencies (e.g., 20MHz, 40MHz, 60MHz) into a single device, enabling it to perform multiple imaging functions including high-resolution imaging, deep penetration imaging, and color-Doppler imaging, thereby greatly improving imaging versatility.
Solution Approach 2:
The system employs dynamic frequency selection where different transducers are activated based on the specific imaging requirements. The control system dynamically selects which transducer to use based on whether deep penetration, high resolution, or Doppler imaging is needed, making the device adaptable to various clinical scenarios.
4Measurement precision
If transducers are positioned perpendicular to blood flow for standard IVUS imaging, then spatial resolution is improved, but Doppler color flow imaging capability deteriorates
Solution Approach 1:
The imaging assembly applies local quality by having different transducers with different orientations and frequencies assigned to different functions. Some transducers are optimized for high-resolution cross-sectional imaging while others are positioned and tilted to generate non-zero Doppler shifts for color flow imaging, allowing each transducer to excel at its specific local 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
The device achieves enhanced imaging capabilities by combining high spatial resolution with sufficient depth penetration and enables effective color-Doppler imaging, overcoming limitations of existing IVUS devices in vascular imaging.
Implementation Method 1
Ultrasonic waves are partially reflected by discontinuities arising from tissue structures (such as the various layers of the vessel wall), red blood cells, and other features of interest. Echoes from the reflected waves are received by the transducer
Implementation Method 2
The transducers emit ultrasonic energy in order to create an image of the vessel of interest
Implementation Method 3
Because an ultrasound transducer operating at a higher center frequency has higher spatial resolution but less depth of penetration than an ultrasound transducer operating at a lower center frequency
Implementation Method 4
Doppler color flow imaging and other Doppler techniques do not function well when the velocity of interest (i.e., blood flow velocity) is perpendicular to the imaging plane and perpendicular to the direction of ultrasound propagation, resulting in near zero Doppler shift attributable to blood flow
Data Source
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AI summary
Intravascular ultrasound (IVUS) imaging devices, systems, and method are provided. In one embodiment, an IVUS imaging device includes a flexible elongate member configured to be positioned within a lumen of a patient, the flexible elongate member comprising a proximal portion and a distal portion; and an imaging assembly disposed at the distal portion of the flexible elongate member. The imaging assembly includes a first ultrasound transducer operating at a first center frequency; and a second ultrasound transducer operating at a second center frequency different from the first center frequency.