Fluorescence Vessel Identification Using Oscillating Micro-Boluses
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Solution Overview
Problem
Existing fluorescence imaging methods require a 20-30 minute washout period after ICG administration, making it difficult to monitor blood vessels during bowel surgery due to peristaltic movements, and there is a need for a tool to distinguish blood vessels from connective tissue, especially in obese patients.
Innovation Solution
A novel administration regime using automated, time-separated micro-boluses of fluorescent agents creates a fluctuating fluorescent signal with a predetermined pattern, allowing continuous perfusion monitoring and identification of blood vessels by analyzing time differences and oscillating patterns in the fluorescent signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a single bolus of fluorescent agent is administered, then a snapshot of perfusion can be obtained, but continuous monitoring is not possible due to the 20-30 minute washout period required
Solution Approach 1:
The system administers periodic micro-boluses of fluorescent agent at intervals shorter than the washout period, creating a continuous train of oscillating signals. This periodic administration allows the fluorescent signal to be continuously present in the tissue without requiring long washout periods between measurements, thereby enabling continuous monitoring while reducing total agent exposure
Solution Approach 2:
The system pre-determines the oscillation pattern parameters (frequency, amplitude) based on expected hemodynamic characteristics before actual measurement begins. This preliminary characterization allows the system to recognize and interpret the oscillating fluorescent signals in real-time, enabling continuous monitoring from the start of micro-bolus administration without requiring extended calibration periods
2Difficulty of detecting and measuring
If traditional fluorescence imaging is used, then blood vessels can be visualized, but blood vessels hidden in connective tissue cannot be distinguished
Solution Approach 1:
The system analyzes local oscillation characteristics (frequency, amplitude, phase) of the fluorescent signal at each pixel or region of interest. By examining the specific oscillation pattern in each local area, the system can identify blood vessels even when they are hidden within connective tissue, as the oscillating signal from flowing blood differs from the static or differently-patterned signal from surrounding tissue
Solution Approach 2:
The system transitions from static snapshot imaging to dynamic continuous monitoring by analyzing the temporal oscillation patterns of the fluorescent signal. The oscillating micro-boluses create time-varying signals that reveal hemodynamic information, allowing the system to distinguish blood vessels based on their dynamic flow characteristics rather than just their static appearance, thereby revealing vessels hidden in connective tissue
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
Enables continuous identification and visualization of blood vessels, reducing surgical complications and time by providing real-time, augmented reality mapping of vessels during surgery, even in challenging anatomies like obese patients.
Implementation Method 1
Fluorescent imaging is one such tool wherein injection of fluorescence imaging agents, aka fluorescent contrast agents, aka fluorescent agents, such as indocyanine green (ICG), is provided to visualize blood flow and perfusion in tissue of anatomical structures
Data Source
Figure 1A~1B
Figure 2A~2D
Figure 3A~3B
AI summary
The present disclosure relates to a system and a method for continuously identifying blood vessels in tissue during fluorescence imaging. In particular the present disclosure relates to continuously measuring and assessing hemodynamics in tissue in medical procedures using fluorescence imaging wherein the administration of the fluorescent agent is controlled and automated and thereby identifying, mapping and visualizing blood vessels in the tissue. One embodiment relates a computer implemented method for identifying blood vessels in tissue of a subject, e.g. during a medical procedure, the method comprising the steps of continuously acquiring fluorescence images of the tissue wherein a fluorescent signal is oscillating with a predetermined pattern, and analysing the fluorescence images and the associated oscillating signal thereby continuously identifying blood vessels in the tissue.