JPWO2020207883A5 - - Google Patents

Claims (13)

A computer-implemented method for determining an estimate of intracranial blood pressure, said method comprising:
obtaining , using transcranial Doppler ultrasound data, a first signal indicative of motion of a brain vessel wall as a function of time;
obtaining a second signal indicative of cerebral blood flow velocity as a function of time using transcranial Doppler ultrasound data ;
obtaining a third signal indicative of blood pressure at a location external to the brain as a function of time;
the first, second, and third signals correspond to measurements taken over the same time period;
The method further comprises detecting a phase offset of the second signal with respect to the first signal;
applying a phase shift to the third signal such that the phase-shifted third signal exhibits a phase offset relative to the second signal by an amount equal to the detected phase offset. , transforming the third signal to obtain a fourth signal indicative of an estimated intracranial blood pressure. 2. The method of claim 1, wherein the method further comprises determining an estimate of intracranial pressure based on the fourth signal and the second signal. 2. The method of claim 1 , wherein the first and second signals are obtained using spectral Doppler signals derived from intracranial Doppler ultrasound data, the spectral Doppler signals representing Doppler velocity as a function of time. . Obtaining the first signal includes extracting relatively low frequency signal components from the spectral Doppler signal, and/or obtaining the second signal compares from the spectral Doppler signal 4. The method of claim 3 , comprising the step of extracting high frequency signal components. The step of detecting the phase offset comprises:
detecting a first point in time of the first signal corresponding to the location of a first predetermined phase point within a cycle;
detecting a second point in time corresponding to the location of a second predetermined phase point within a corresponding cycle of the second signal;
and determining a time difference by subtracting said second time point value from said first time point value. applying a phase shift to the third signal such that the third signal exhibits a time offset relative to the second signal by an amount equal to the determined time difference; 6. The method of claim 5 , comprising shifting the waveform of in the time domain. 7. A method according to any preceding claim, wherein the method comprises receiving intracranial ultrasound data from a transcranial ultrasound transducer unit. The method further comprises applying beamforming to the received transcranial ultrasound data according to one or more beamforming settings and representing the quality of the data for deriving flow velocity and/or vessel wall motion. applying signal analysis processing to determine a quality metric of the beamformed data . 9. The method of claim 8 , further comprising adjusting the one or more beamforming settings based on the determined quality metric. A processing unit for obtaining an estimate of intracranial blood pressure, said processing unit being adapted in use to acquire transcranial Doppler ultrasound data from said transcranial ultrasound transducer unit. , said processing unit performing a method according to any one of claims 1 to 9 . A computer program product comprising instructions enabling a processing unit according to claim 10 to implement the method according to any one of claims 1 to 9. a processing unit according to claim 10 ;
a transcranial ultrasound transducer unit operatively coupled to said processing unit. 13. A patient monitor comprising the processing unit of claim 10 or the ultrasound system of claim 12 , said patient monitor being communicatively coupled to a blood pressure measuring device, and said patient monitor comprising said A patient monitor for obtaining said third signal from a blood pressure measuring device and transmitting said signal to said processing unit for use in deriving said fourth signal.