Intravascular OCT Flow Measurement for Mean Transit Time
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Solution Overview
Problem
Current methods for determining microvascular resistance, such as using pressure wires and angiography, are cumbersome and risky due to the need for multiple instruments, and they require additional steps that complicate the procedure.
Innovation Solution
Utilizing a single intravascular imaging probe, such as an OCT or IVUS probe, to collect data for determining mean transit time and microvascular resistance by analyzing cross-sectional areas of a bolus within the blood vessel, allowing for simultaneous diagnosis of microvascular disease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure wire and angiography are used to collect data for identifying microvascular disease, then measurement precision is improved, but device complexity and procedure time increase
Solution Approach 1:
The patent combines the intravascular imaging function with the flow measurement function into a single integrated catheter system. The OCT catheter includes both imaging capabilities and temperature sensors, allowing simultaneous acquisition of anatomical data and flow data without requiring separate pressure wires and angiography equipment, thus reducing device complexity while maintaining measurement precision
Solution Approach 2:
The intravascular imaging catheter is designed to perform multiple functions: it provides intravascular imaging for anatomical assessment and simultaneously measures flow rate through temperature sensor detection of chilled saline bolus. This multi-functional device eliminates the need for multiple specialized instruments, reducing overall procedure complexity
2Measurement precision
If pressure wire and angiography are used to collect data for identifying microvascular disease, then measurement precision is improved, but procedure time increases
Solution Approach 1:
By integrating flow measurement capability into the intravascular imaging catheter, the patent enables simultaneous collection of both anatomical and flow data during a single procedure. This eliminates the sequential steps of performing separate pressure wire measurements and angiography, significantly reducing procedure time while maintaining comprehensive diagnostic capability
Solution Approach 2:
The system performs flow measurement using chilled saline bolus injection while the catheter is positioned in the target location, allowing flow data to be collected during the imaging procedure itself rather than requiring separate preliminary or subsequent measurements. This preliminary integration of measurement functions reduces overall procedure time
3Measurement precision
If multiple instruments are used for data collection, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent merges multiple data collection functions into a single catheter system that can be inserted and operated as one unit. The integrated design with combined imaging and temperature sensing capabilities simplifies the operation workflow, reducing the complexity of coordinating multiple instruments while maintaining comprehensive measurement precision
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 reduces patient risk and procedure time by using a single probe to collect data, enabling efficient diagnosis of microvascular disease and providing indicators like CFR and IMR, thereby improving diagnostic efficiency and accuracy.
Implementation Method 1
an intravascular imaging probe may be an OCT probe, an intravascular ultrasound ('IVUS') probe, micro-OCT probe, near infrared spectroscopy (NIRS) sensor, or any other device that can be used to image a blood vessel
Implementation Method 2
The temperature of the bolus is measured as the bolus passes by a proximal and distal temperature sensor on a pressure wire, which is inserted separate from an imaging catheter, such as an optical coherence tomography ('OCT') catheter. A thermodilution curve is then plotted based on the temperature of the bolus as it passes the temperature sensors
Data Source
AI summary
The present disclosure provides systems and methods for determining a mean transit time of a bolus within the blood vessel by passing the bolus through the blood vessel while an intravascular imaging probe is held stationary. The probe may collect a plurality of image frames as the bolus passes the probe. The cross-sectional area of the bolus within the images frames may be determined by segmenting each image frame by thresholding, creating a vessel mask, and creating a contrast mask by applying an element-wise AND operator to the thresholded image and the vessel mask. The cross-sectional area of the bolus for the image frames may be plotted on an area dilution curve. Various fits may be applied to and various points may be identified on the area dilution curve. The various fits and points may be used to determine the mean transit time.