Intracranial Pressure Estimation via Phase-Shifted Blood Pressure Signals
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Solution Overview
Problem
Current methods for measuring intracranial pressure (ICP) are invasive and cannot be performed outside a hospital setting, limiting their availability for early detection of traumatic brain injuries, and non-invasive methods struggle to accurately estimate ICP due to phase variations in blood pressure waveforms across different body locations.
Innovation Solution
A method that involves obtaining signals for cerebral blood vessel wall movement and blood flow velocity, detecting a phase offset, and applying a phase shift to blood pressure signals measured outside the brain to align them with the intracranial signals, allowing for accurate estimation of intracranial pressure using transcranial Doppler ultrasound data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive methods are used to measure intracranial pressure, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent uses transcranial Doppler ultrasound as an intermediary to measure cerebral blood flow velocity, which serves as a surrogate marker for intracranial pressure. This indirect measurement approach avoids the need for invasive skull penetration while still providing clinically useful ICP estimation, resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent replaces the mechanical invasive pressure sensing system with a non-invasive ultrasound-based blood flow velocity measurement system. By substituting the direct pressure measurement mechanism with a blood flow velocity measurement that correlates with ICP, the system achieves comparable measurement precision without the complexity and invasiveness of traditional methods
2Ease of operation
If non-invasive blood pressure devices are used, then ease of operation is improved, but measurement precision deteriorates due to phase variations
Solution Approach 1:
The patent employs feedback by detecting the phase offset between the measured blood pressure waveform and the cerebral blood flow velocity waveform, then using this detected phase offset to correct the blood pressure signal. This feedback mechanism ensures that the transformed blood pressure signal accurately reflects intracranial conditions, resolving the precision issue while maintaining ease of operation
Solution Approach 2:
The patent changes the parameters of the blood pressure signal by applying a phase shift transformation based on the detected phase offset. This parameter modification aligns the external blood pressure signal with the intracranial blood flow velocity signal, thereby improving measurement precision without compromising the non-invasive ease of operation
3Ease of operation
If blood pressure signals from outside the brain are used, then ease of operation is improved, but reliability deteriorates due to phase offset
Solution Approach 1:
The system uses feedback by continuously monitoring the phase relationship between external blood pressure signals and intracranial blood flow velocity, detecting the phase offset, and applying corrective phase shifts to ensure the external signal accurately represents intracranial conditions, thereby maintaining reliability
Solution Approach 2:
The patent creates a corrected copy of the external blood pressure signal that has been phase-shifted to match the intracranial blood flow velocity waveform. This copied and transformed signal reliably represents intracranial pressure conditions while maintaining the ease of using external measurement devices
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 non-invasive and accurate estimation of intracranial pressure, improving the ability to detect traumatic brain injuries in non-hospital settings by synchronizing blood pressure signals with intracranial blood flow velocity, thus providing a reliable and safer monitoring solution.
Implementation Method 1
transcranial Doppler (TCD) ultrasound and arterial blood pressure measurements
Data Source
AI summary
A method (20) and device for deriving an estimate of intracranial blood pressure based on motion data for a wall of an intracranial blood vessel, intracranial blood flow velocity, and a blood pressure signal measured at a location outside the brain. The method is based on identifying (28) a time offset between the two intracranial signals (vessel wall movement and vessel blood flow), and then applying (30) this offset to the blood pressure signal acquired from outside the brain to obtain a fourth signal, indicative of estimated intracranial blood pressure.