pMUT Ultrasonic Catheter Insulating Coating Acoustic Matching
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Solution Overview
Problem
Current intracardiac echocardiography (ICE) catheters lack flexibility during insertion, may cause patient discomfort, and pose electrical risks due to inadequate electrical insulation and acoustic mismatch with bodily fluids, limiting their effectiveness in imaging cardiac structures.
Innovation Solution
An ultrasonic catheter with a Piezoelectric Micromachined Ultrasonic Transducer (pMUT) array coated with an electrically insulating material, such as polyether block amide (PEBA) or thermoplastic elastomer (TPE), to provide electrical isolation and improve signal transmission, reducing electrical leakage and breakdown risks while allowing flexible insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an ultrasonic catheter is inserted inside the heart for imaging, then high-resolution real-time visualization of cardiac structures is achieved, but infection risk to the insertion passage increases and patient discomfort occurs
Solution Approach 1:
An acoustic matching layer is introduced as an intermediary between the ultrasonic transducer array and the bodily fluids (blood). This layer has acoustic impedance intermediate between the transducer material and blood, enabling efficient acoustic energy transmission while the transducer remains isolated from direct contact with blood, thereby reducing infection risk and patient discomfort
Solution Approach 2:
The catheter is designed as a single-use disposable device. After one patient use, the entire catheter is discarded, eliminating the risk of cross-contamination and infection transmission between patients. This approach prioritizes patient safety by ensuring the catheter never re-enters the bloodstream
2Measurement precision
If electrical impulses are supplied to the transducer array for ultrasonic transmission, then imaging function is achieved, but electrical leakage and breakdown risks occur due to inadequate insulation
Solution Approach 1:
An electrically insulating acoustic matching layer serves as a mediator between the electrically active transducer array and the conductive bodily fluids. This layer provides both acoustic impedance matching for efficient ultrasound transmission and electrical insulation to prevent current leakage and breakdown, thereby ensuring both imaging function and electrical safety
Solution Approach 2:
A thin film insulating coating is applied over the transducer array elements. This thin film provides sufficient electrical insulation against bodily fluids while being acoustically transparent enough to allow ultrasound transmission. The flexible nature of the thin film allows it to conform to the curved surface of the catheter tip
3Measurement precision
If the transducer array is inserted inside the heart, then cardiac structure imaging is achieved, but acoustic mismatch with bodily fluids reduces signal quality
Solution Approach 1:
An acoustic matching layer with intermediate acoustic impedance is positioned between the transducer array and the blood. This intermediary layer reduces the acoustic impedance mismatch, enabling more efficient transmission of ultrasonic energy into the bodily fluids and improving the strength and quality of returned echo signals for better imaging
Solution Approach 2:
The acoustic impedance parameter of the interface between transducer and bodily fluid is optimized by introducing a matching layer. The layer's acoustic impedance is specifically selected to be between that of the transducer material and blood, creating a gradual transition that minimizes acoustic reflection and maximizes energy transmission
4Stability of the object's composition
If the catheter structure is made rigid for structural stability, then transducer array positioning is maintained, but flexibility during insertion is reduced
Solution Approach 1:
The catheter is divided into segments with different mechanical properties: a flexible distal section containing the transducer array for easy navigation through vasculature, and a more rigid proximal section for stable handling and positioning. This segmentation allows the catheter to be both flexible during insertion and stable during operation
Solution Approach 2:
The catheter shaft is constructed with flexible materials and a hollow tubular structure that provides flexibility for navigation through the vascular system while maintaining sufficient structural integrity to support and position the transducer array accurately at the target location
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 solution enables stable and repeatable transmission of ultrasound signals, enhances patient comfort by reducing electrical risks, and improves imaging quality through better acoustic matching with bodily fluids, facilitating more precise cardiac procedures.
Implementation Method 1
A Piezoelectric Micromachined Ultrasonic Transducer (pMUT) array is disposed within the distal end of the ultrasonic catheter
Implementation Method 2
The insulating material is disposed at the distal end of the ultrasonic catheter over an imaging window, to provide electrical isolation and provide transmission of ultrasound signals
Data Source
AI summary
An ultrasonic catheter is disclosed. The ultrasonic catheter comprises a body having a longitudinal axis and a distal end. A Piezoelectric Micromachined Ultrasonic Transducer (pMUT) array is disposed within the distal end of the body. Further, the pMUT array comprises a plurality of pMUT array elements arranged on a substrate. Further, an insulating material is disposed at the distal end over an imaging window, to provide electrical isolation and transmission of ultrasound signals. The insulating material corresponds to a polyether block amide (PEBA) or Pebax, or thermoplastic elastomer (TPE).