Dynamic Scan Interval Control for OCT Blood Flow Detection
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Solution Overview
Problem
Current surface scanning technologies face limitations in achieving a wide and dynamic time interval between scans, particularly in medical imaging applications like OCT angiography and Doppler-OCT, which restricts the detection and measurement of blood flow rates across vessels of varying diameters and velocities, leading to reduced sensitivity for slow blood flow and increased complexity in imaging speed and accuracy.
Innovation Solution
Configurable surface scan patterns and protocols using modified waveforms such as sinusoidal, sawtooth, and frequency-modulated waveforms that allow for variable scan rates on both fast and slow axes, enabling a wide and dynamic time interval between scans, thereby improving the scanning mirror's operation and reducing mechanical inertia dependencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed scanning time interval is used, then the imaging system can operate with simple timing control, but the sensitivity to detect blood flow at different velocities is reduced
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed scanning time interval to a dynamic, variable scanning time interval that adapts to different blood flow velocities. The scanning system adjusts the time interval between B-scans based on the detected motion magnitude, allowing optimal detection sensitivity for both slow and fast blood flow without requiring multiple fixed-rate scans.
Solution Approach 2:
The patent changes the timing parameter (scanning time interval) dynamically based on detected signal characteristics. By modifying the scanning time interval according to the magnitude of motion detected in previous scans, the system optimizes its measurement parameters adaptively, improving blood flow detection sensitivity across varying velocities.
2Adaptability or versatility
If multiple time intervals are used to detect different blood flow velocities, then the detection range is improved, but the system complexity increases
Solution Approach 1:
The patent implements a dynamic scanning protocol where the scanning time interval automatically adjusts based on real-time detection of blood flow characteristics. This single adaptive protocol replaces the need for multiple fixed-rate scanning sequences, simplifying the overall system control while maintaining the ability to detect a wide range of blood flow velocities.
Solution Approach 2:
The system uses feedback from previous scan results to control future scanning parameters. The magnitude of motion detected in earlier B-scans feeds back into the timing control mechanism, automatically adjusting subsequent scanning intervals to match the detected blood flow velocity, thereby simplifying multi-velocity detection through intelligent feedback control.
3Speed
If a short scan time interval is used, then fast blood flow can be detected, but the sensitivity to slow blood flow is reduced
Solution Approach 1:
The patent employs dynamic adjustment of the scanning time interval that responds to the detected blood flow characteristics. When fast blood flow is detected, the system uses shorter intervals to capture rapid motion; when slow blood flow is present, the system automatically extends the interval to improve sensitivity, thereby resolving the trade-off between detecting fast and slow flow.
Solution Approach 2:
The system changes the scanning time interval parameter dynamically based on the magnitude of motion detected in previous scans. This adaptive parameter adjustment allows the system to optimize its temporal resolution for the current blood flow conditions, maintaining both speed for fast flow detection and sensitivity for slow flow detection.
4Measurement precision
If a long scan time interval is used, then slow blood flow sensitivity is improved, but the imaging speed decreases
Solution Approach 1:
The patent implements dynamic scanning interval adjustment that extends the time interval only when slow blood flow is detected, rather than using a consistently long interval. This allows the system to maintain high imaging speed for fast-flow scenarios while achieving improved sensitivity for slow-flow detection when needed.
Solution Approach 2:
The scanning time interval parameter is adjusted dynamically based on detected blood flow velocity characteristics. The system extends the interval selectively to improve slow flow sensitivity only when required, thereby maintaining overall high imaging productivity while enabling sensitive detection of slow blood flow when present.
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 allows for enhanced detection and measurement of blood flow rates across a wide range of velocities, improving imaging speed and accuracy by dynamically adjusting the time interval between scans, thus overcoming the limitations of fixed time intervals and mechanical dependencies in existing technologies.
Implementation Method 1
a light beam is directed to a scanning mirror to deflect the light beam across a surface
Data Source
AI summary
A method of data acquisition and image generation over a wide and dynamic time interval between surface scans using modified electrical waves is disclosed. It is also disclosed that generating altered electrical waveforms that drive a scanner using conventional waves such as sinusoidal or triangle or sawtooth can enhance the method. Systems for A-scan, B-scan, and C-scan imaging pp include surface scan setups using a one-dimensional and a two-dimensional scanner, respectively. Three different arrangements of conventional waves enable modified waveforms that drive scanners to produce a wide and dynamic interscans time interval on both the fast and slow scan axes. (i) At a constant peak-to-peak voltage, the instantaneous voltage of the electrical sinusoidal wave shifts in time with the amplitude of the electrical signal in the ramp waveform within a range. (ii) The frequency of a waveform continuously increases (up-chirp) as a function of time in the form of a positive ramp sawtooth or continuously decreases as a function of time in the form of a negative ramp sawtooth. (iii) The frequency of a waveform is modulated as a function of time in a 90-degree phase retarded sinusoidal form within a deviation range of the +/â peak frequency.