Non-Invasive ICP Measurement via Retinal Venous Pulsations
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Solution Overview
Problem
Current methods for measuring intracranial pressure (ICP) are invasive, risky, and not suitable for continuous monitoring outside a hospital setting, limiting their availability and accuracy, especially for patients recovering from conditions like stroke or traumatic brain injury.
Innovation Solution
A non-invasive method that detects spontaneous retinal venous pulsations (SRVPs) by tilting the head to create a hydrostatic pressure difference between intracranial and intraocular pressure, using sensors to determine the angle at which SRVPs appear or disappear, allowing for the estimation of ICP without the need for invasive procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive ICP measurement methods (intraventricular drain or intraparenchymal probes) are used, then measurement precision is improved, but device complexity and patient risk increase
Solution Approach 1:
The patent uses retinal vein as an intermediary structure to indirectly measure ICP. By observing SRVPs in the retinal vein, which is connected to both the intracranial space and the eye, the system obtains ICP information without direct intracranial access, thus avoiding the complexity and risks of invasive procedures while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical invasive measurement system (catheters, probes, surgical drains) with an optical observation system. Using imaging technology to detect retinal vein pulsations substitutes the need for physical intrusion into the cranial cavity, eliminating surgical complexity while preserving ICP measurement function
2Measurement precision
If invasive ICP measurement methods are used, then measurement precision is improved, but patient safety deteriorates
Solution Approach 1:
The retinal vein serves as a safe intermediary that provides access to ICP information without breaching the blood-brain barrier or requiring intracranial foreign bodies. This eliminates the primary sources of infection and complications associated with invasive catheters and probes
Solution Approach 2:
The patent converts the previously harmful effect of elevated ICP on retinal vein pulsations into a beneficial diagnostic signal. The suppression or alteration of SRVPs in elevated ICP conditions becomes the measurement mechanism itself, transforming a pathological effect into a useful indicator without exposing the patient to invasive risks
3Object-affected harmful factors
If non-invasive ICP assessment techniques are used, then patient safety is improved, but measurement precision deteriorates
Solution Approach 1:
The system continuously monitors SRVPs in the retinal vein and uses this feedback to determine ICP status. By establishing the relationship between SRVP characteristics and ICP levels, the system achieves accurate non-invasive measurement through ongoing observation of physiological responses to pressure changes
Solution Approach 2:
The patent measures changes in retinal vein pulsation parameters (presence, amplitude, frequency of SRVPs) in response to head position changes that alter the hydrostatic pressure gradient between intracranial and intraocular spaces. These parameter changes provide precise ICP information without invasive measurement
4Ease of operation
If current non-invasive ICP techniques are used, then ease of operation is improved, but reliability deteriorates
Solution Approach 1:
The system enables continuous monitoring of ICP by continuously detecting SRVPs in the retinal vein. Unlike intermittent invasive measurements or limited non-invasive techniques, this approach provides ongoing reliable data for clinical decision-making, maintaining both ease of operation and clinical reliability
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 minimally intrusive and continuous ICP monitoring, potentially allowing patients to monitor their pressure at home, reducing the risks associated with invasive methods and improving accessibility for ongoing ICP management.
Implementation Method 1
tilting the head to create a hydrostatic pressure difference between intracranial and intraocular pressure
Data Source
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Figure 3(a)~3(c)
AI summary
According to an aspect, there is provided a method for measuring the intracranial pressure, ICP, in a subject, the method comprising detecting whether spontaneous retinal venous pulsations, SRVPs, are occurring in an eye of the subject as the orientation of the head of the subject changes; identifying the orientation of the head of the subject at which SRVPs start to occur or stop occurring; and using the identified orientation of the head of the subject at which SRVPs start to occur or stop occurring to determine the ICP in the subject.