Non-imaging tFUS Probe Targeting via MRI Overlay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current transcranial focused ultrasound (tFUS) systems face challenges in accurately delivering ultrasound stimulation to deep and small anatomical targets within the brain, such as the amygdala, due to the skull's curvature and thickness variations, leading to inefficiencies and potential side effects.
Innovation Solution
The use of simple, low-frequency probe designs, such as annular arrays and low-element-count non-imaging matrix arrays, in conjunction with infrared or optical systems for positional guidance, allows for reliable delivery of ultrasound stimulation. These systems simulate the spatial distribution of the ultrasound field and overlay it with pre-procedure MRI data to ensure accurate targeting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high channel count array systems are used to image brain anatomy and guide stimulation, then targeting accuracy is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The system divides the transducer into multiple independent channels (e.g., 192 channels) that can be individually controlled. Each channel acts as an independent element that can be selectively activated to achieve precise focal point control without requiring a fully dense array, thereby reducing overall system complexity while maintaining targeting accuracy.
Solution Approach 2:
The patent introduces an acoustic hologram as an intermediary computational model that maps the desired acoustic field distribution to the transducer element activations. This intermediary layer simplifies the control problem by providing a direct computational pathway from target geometry to element firing patterns, reducing the complexity of real-time control algorithms.
2Measurement precision
If high-frequency ultrasound is used to resolve brain structures for imaging guidance, then measurement precision is improved, but skull aberration control becomes more difficult
Solution Approach 1:
The system performs preliminary skull mapping and acoustic property characterization before the actual stimulation procedure. By measuring skull thickness, density, and acoustic properties in advance using the same transducer array, the system pre-compensates for skull aberrations, making the subsequent high-frequency stimulation more effective and reducing the complexity of real-time aberration correction.
Solution Approach 2:
The patent dynamically adjusts multiple parameters including frequency, amplitude, phase, and focal depth for each transducer channel based on the measured skull properties and desired target geometry. This multi-parameter optimization allows the system to compensate for skull aberrations effectively while maintaining the high-frequency resolution needed for precise brain structure targeting.
3Device complexity
If simple low-frequency probe designs are used for tFUS, then device complexity is reduced, but the ability to accurately target deep and small brain structures deteriorates
Solution Approach 1:
The system employs dynamic focusing and beam steering capabilities that allow the focal point to be moved precisely to any depth and lateral position within the brain by adjusting the phase and timing of each transducer channel. This dynamic control compensates for the lower frequency of the probe, maintaining targeting precision for deep and small structures while keeping the probe design simpler than high-frequency imaging systems.
Solution Approach 2:
The patent utilizes the temporal dimension by employing pulsed ultrasound sequences with precisely controlled timing across multiple channels. This temporal coding, combined with spatial phase control, creates an additional degree of freedom for focusing energy at specific deep brain locations, effectively compensating for the reduced spatial resolution inherent in low-frequency probes.
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 enables high-efficacy tFUS treatment by ensuring accurate and reliable delivery of ultrasound stimulation to targeted brain anatomy, reducing the risk of side effects and improving treatment outcomes.
Implementation Method 1
transcranial focused ultrasound (tFUS) systems
Implementation Method 2
deliver US stimulation to the targeted brain anatomy
Implementation Method 3
Substantial losses of efficacy in tFUS derive from the acoustic beam partly or entirely missing the target
Implementation Method 4
the skull's curvature or variation in its thickness complicates the ultrasound (US) delivery
Implementation Method 5
simulate the spatial distribution of the ultrasound field of the ultrasound probes
Data Source
AI summary
Systems and methods using non-imaging transcranial focused ultrasound (tFUS) systems are described. Non-imaging annular and matrix probes with low element counts are used in the systems. In an embodiment, an infrared-based system is used to gather the ultrasound's position information on the scalp. The position information is used to simulate the spatial distribution of the ultrasound field of the ultrasound probes. The simulation output is overlaid with pre-procedure MRI data and displayed to a clinician. Measurements on the MRI data are used to compensate the beam formation for the acoustic behavior of the skull so that a desirable tFUS focal region is achieved. In a different embodiment, an optical system is used for gathering positional information.