Blood Volume Flow Measurement Using Fluorescent Transit Time
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Solution Overview
Problem
Current methods for determining blood volume flow through a blood vessel during surgical operations lack accuracy due to dependencies on vessel diameter and spatial environment, with no clear calculation rules for correcting deviations in measured values.
Innovation Solution
A computer-implemented method using a blood vessel model, fluid flow model, and fluorescent light model to calculate blood volume flow by processing images of fluorescent light, adapting a blood vessel model, and applying fluid flow and light models to determine flow velocities and light intensity, thereby correcting for errors and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fluorescence angiography methods are used to determine blood volume flow, then the measurement process is simple and quick, but the measurement precision deteriorates due to dependencies on vessel diameter and spatial environment
Solution Approach 1:
The patent applies preliminary action by pre-defining the blood vessel model, fluid flow model, and fluorescent light model before performing the measurement. These models are prepared in advance with all necessary parameters and relationships established, so that during the actual measurement process, the system only needs to input basic parameters (vessel length, diameter, transit time) to automatically calculate the blood volume flow using the pre-established models, thereby achieving high precision without complex real-time calculations
Solution Approach 2:
The patent introduces computational models as intermediaries between the raw fluorescence measurements and the final blood volume flow calculation. The blood vessel model, fluid flow model, and fluorescent light model serve as intermediary layers that translate simple measurable parameters into accurate blood flow values, compensating for various influencing factors without requiring complex direct measurements
2Reliability
If simple intensity-based flow determination is used, then the ease of operation is high, but the reliability deteriorates due to uncorrected deviations dependent on vessel diameter
Solution Approach 1:
The patent applies parameter changes by transforming the measurement from simple intensity-based determination to a multi-parameter calculation approach. Instead of relying solely on fluorescence intensity, the system incorporates vessel length, vessel diameter, and transit time as key parameters, along with correction factors from the models, to reliably determine blood volume flow across different vessel sizes and conditions
Solution Approach 2:
The patent replaces manual intensity-based estimation with an automated computational system. The computer-implemented method automatically processes the fluorescence images, extracts parameters, applies the models, and calculates the blood volume flow, eliminating the need for manual correction and ensuring consistent reliable results while maintaining ease of operation through automation
3Measurement precision
If detailed modeling approaches are applied to correct for spatial environment dependencies, then the measurement precision improves, but the loss of time increases due to complex calculations
Solution Approach 1:
The patent resolves the time-precision contradiction by performing preliminary action: the complex models are pre-configured with all necessary relationships and correction factors before measurement. During the actual blood flow determination, the system only needs to input basic parameters and the pre-established models automatically perform the complex calculations, achieving both high precision and fast results
Solution Approach 2:
The patent uses copying by creating simplified computational representations (models) of the complex physical processes. The blood vessel model, fluid flow model, and fluorescent light model are computational copies that replicate the essential physics and relationships, allowing fast calculation while maintaining measurement precision through the accurate representation of underlying physical principles
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 method provides an accurate determination of blood volume flow by accounting for vessel geometry and light propagation, reducing errors and enhancing precision in surgical operations.
Implementation Method 1
a plurality of images are provided which are based on fluorescent light in the form of light having wavelengths lying within a fluorescence spectrum of the fluorophore
Data Source
AI summary
The invention relates to a computer-implemented method (10) for determining the blood volume flow (IBI) through a portion (90i, i=1, 2, 3, . . . ) of a blood vessel (88) in an operating region (36) using a fluorophore. A plurality of images (801, 802, 803, 804, . . . ) are provided, which are based on fluorescent light in the form of light having wavelengths lying within a fluorescence spectrum of the fluorophore, and which show the portion (90i) of the blood vessel (88) at different recording times (t1, t2, t3, t4, . . . ). By processing at least one of the provided images (801, 802, 803, 804, . . . ), a diameter (D) and a length (L) of the portion (90i) of the blood vessel (88) and also a time interval for a propagation of the fluorophore through the portion (90i) of the blood vessel (88) are determined, which time interval describes a characteristic transit time (τ) for the fluorophore in the portion (90i) of the blood vessel (88), in which a blood vessel model (MBQ) for the portion (90i) of the blood vessel (88) is specified, which blood vessel model describes the portion (90i) of the blood vessel (88) as a flow channel (94) having a length (L), having a wall (95) with a wall thickness (d), and having a free cross section Q. A fluid flow model MFQ for the blood vessel model (MBQ) is assumed, which fluid flow model describes a local flow velocity (122) at different positions over the free cross section Q of the flow channel (94) in the blood vessel model (MBQ), and a fluorescent light model MLQ is assumed, which describes a spatial probability density for the intensity of the remitted light at different positions over the free cross section Q of the flow channel (94) in the blood vessel model (MBQ), which light is emitted by a fluid, which is mixed with fluorophore and flows through the free cross section Q of the flow channel (94) in the blood vessel model (MBQ), when said fluid is irradiated with fluorescence excitation light. The blood volume flow (IBI) is determined as a fluid flow guided through the flow channel (94) in the blood vessel model (MBQ), which fluid flow is calculated from the length (L) and the diameter (D) of the portion (90i) of the blood vessel (88) and from the characteristic transit time (τ) for the fluorophore in the portion (90i) of the blood vessel (88), using the fluid flow model MFQ and the fluorescent light model MLQ.