Ultrasound Transducer Array Aberration Correction via Angular Spectrum
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Solution Overview
Problem
Current ultrasound systems face limitations in imaging and targeting due to aberrations in heterogeneous surfaces, low diffraction limits, and the inability to adjust pressure and frequency effectively for precise therapeutic interventions, particularly in treating brain disorders where cavitation events are undesirable and invasive placement is required.
Innovation Solution
The implementation of a feedback-controlled system that uses a transducing platform with multiple transducers to provide ultrasound waves through different sections of a surface with varying sound speeds, calculating angular spectra, and phase correcting signals to determine desired pressure levels and delay settings for precise targeting and imaging, while also employing morphological reconstruction and Euclidean minimum spanning tree methods for super-resolution imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasound waves are passed through heterogeneous surfaces like the skull for brain imaging, then imaging capability is achieved, but aberrations occur that degrade image quality and localization accuracy
Solution Approach 1:
The system dynamically adjusts ultrasound wave parameters including frequency, amplitude, and phase to compensate for aberrations introduced by heterogeneous surfaces. By changing these parameters in real-time based on feedback from detected signals, the system maintains both imaging quality and localization accuracy despite variations in the propagation medium.
Solution Approach 2:
The patent implements a feedback-controlled system that detects signals from microbubbles or scatterers and uses this information to adjust subsequent ultrasound wave transmission. This closed-loop approach allows the system to correct for aberrations caused by heterogeneous surfaces, improving both image quality and localization precision iteratively.
2Manufacturing precision
If conventional ultrasound imaging is used, then imaging is achieved, but resolution is limited by diffraction to about a millimeter
Solution Approach 1:
The system segments the imaging process into multiple sequential localizations of individual microbubbles rather than attempting to image all sources simultaneously. By localizing one bubble at a time and accumulating positions over multiple frames, the system achieves super-resolution imaging that overcomes the diffraction limit, resolving structures at the sub-millimeter scale.
Solution Approach 2:
The patent transitions from spatial resolution alone to temporal dimension by using successive localizations over time. By tracking microbubbles across multiple frames and using their temporal trajectories, the system achieves resolution beyond the conventional diffraction limit, effectively adding a temporal dimension to the imaging process.
3Measurement precision
If high power arrays are used to overcome cavitation threshold for aberration correction, then imaging capability is improved, but risk of unwanted cavitation events increases
Solution Approach 1:
The system uses feedback control to monitor the acoustic field and adjust transmission power dynamically. By detecting the presence and response of microbubbles in real-time, the system can achieve aberration correction at lower power levels than traditional methods, maintaining imaging quality while significantly reducing the risk of unwanted cavitation events.
Solution Approach 2:
The patent implements dynamic adjustment of ultrasound wave parameters including frequency, amplitude, and duration based on real-time feedback. This dynamic approach allows the system to optimize the balance between achieving sufficient aberration correction and minimizing cavitation risk, adapting parameters moment-by-moment rather than using fixed high-power settings.
4Reliability
If invasive placement of point source within skull is performed, then effective trans-skull therapy is achieved, but procedural complexity and risk increase
Solution Approach 1:
The system uses microbubbles as intermediary targets that can be introduced systemically into the bloodstream rather than requiring invasive placement. These microbubbles serve as effective mediators for trans-skull therapy, allowing the system to achieve therapeutic effectiveness through non-invasive ultrasound delivery while the microbubbles concentrate the acoustic energy at the desired brain targets.
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
This approach enhances focal accuracy, reduces localization errors, and improves imaging resolution beyond the diffraction limit, enabling fast and adjustable feedback mechanisms for effective ultrasound wave control, thereby improving therapeutic interventions and diagnostic imaging capabilities.
Implementation Method 1
providing a first set of ultrasound waves through a first section of the surface, the first set of ultrasound waves propagating through the first section of the surface at a first sound speed; providing a second set of ultrasound waves through a second section of the surface, the second set of ultrasound waves propagating through the second section of the surface at a second sound speed
Implementation Method 2
receiving a first set of signals emanating from the region of interest; receiving a second set of signals emanating from the region of interest; calculating an angular spectrum of the first set of signals and the second set of signals
Implementation Method 3
The angular spectrum can be calculated at least in part based on the first sound speed and the second sound speed
Data Source
AI summary
Systems and methods for ultrasound imaging and targeting. The systems and methods can improve targeting and imaging through a heterogenous medium by using the angular spectrum approach (ASA) alone or in combination with passive acoustic mapping (PAM). The systems and methods can improve the ultrasound imaging of vessels using microbubbles. The imaging of the vessels is also aided by the ASA and PAM. A closed loop controller is described that adjusts the ultrasound pressure provided to a region of interest to a desired pressure based at least in part on the harmonic, ultra-harmonic, sub-harmonic, or broadband frequency ranges for the microbubbles.