Heart Valve Geometry Reconstruction from CT Landmarks
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Solution Overview
Problem
Existing methods for pre-procedural planning in transcatheter aortic valve replacement (TAVR) face challenges due to blooming artifacts from metallic stents and low signal strength of bioprosthetic leaflets in CT scans, making accurate segmentation and prediction of coronary obstruction difficult, with prior art methods being complicated and incomplete.
Innovation Solution
An image-based registration framework is used to reconstruct patient-specific valve geometry by aligning a known valve model with patient-specific CT scans, employing a multi-pass registration process involving landmark selection, intensity-based nonrigid B-spline registration, and transformation of the clean stent model to match the patient's CT scan, ensuring high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CT or MRI imaging scans are used to obtain patient-specific geometry, then accurate anatomical data is obtained, but the imaging process is time-consuming and requires the patient to be transported to a scanner
Solution Approach 1:
The patent creates a physical copy of the patient's anatomy using an impression material that captures the geometrical features directly at the clinic, eliminating the need for time-consuming CT or MRI scanning and transport. The impression serves as a direct replica that can be processed locally to generate the implant geometry.
2Ease of manufacture
If conventional implant designs are used, then manufacturing is simplified, but the implant does not conform to the patient's specific anatomical geometry
Solution Approach 1:
The patent performs preliminary action by capturing the patient's anatomical geometry through an impression before the implant fabrication process. This pre-captured geometry data is then used to generate a customized implant design that conforms precisely to the patient's anatomy, while still allowing for efficient manufacturing through additive manufacturing or other fabrication methods.
3Manufacturing precision
If patient-specific implants are manufactured using traditional methods, then anatomical conformity is achieved, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent changes the manufacturing parameter from traditional subtractive or formative methods to additive manufacturing (3D printing), which can efficiently produce complex patient-specific geometries without significantly increasing manufacturing complexity. The digital model derived from the impression can be directly fabricated using additive processes, reducing overall complexity compared to traditional custom implant manufacturing.
Data Source
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Figure 2D~2F
AI summary
A model of an in vivo heart valve device implanted in a patient is generated by providing a known model of a pre-implantation heart valve device, performing an imaging scan on the patient having an implanted heart valve device to obtain at least one patient specific landmark, deforming the known model to fit the at least one patient specific landmark to obtain a constructed patient-specific valve model, and simulating a valve leaflet and skirt for the constructed patient-specific valve model by finite element analysis. The constructed patient-specific valve model accurately represents geometries of the implanted heart valve device in its current in vivo form with an error less than 0.5 mm.