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05:57
Blood Flow Imaging with Ultrafast Doppler
Published on: October 14, 2020
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Non-Invasive Pressure Reactivity Index Using Doppler Systolic Flow Parameters: A Pilot Analysis.
Frederick A Zeiler1,2,3, Peter Smielewski4, Andrew Stevens1
11 Divisions of Anaesthesia, Addenbrooke's Hospital, University of Cambridge , Cambridge, United Kingdom .
Journal of Neurotrauma
|August 10, 2018
Summary
This study shows that pressure reactivity index (PRx) can be predicted using non-invasive transcranial Doppler (TCD) measures. These findings suggest a potential for non-invasive monitoring of cerebrovascular reactivity.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Medical Physics
Background:
- Intracranial pressure (ICP) monitoring is crucial for managing severe brain injuries.
- Non-invasive methods for assessing cerebrovascular reactivity are highly desirable.
- Pressure reactivity index (PRx) is a key indicator of cerebrovascular autoregulation.
Purpose of the Study:
- To predict the pressure reactivity index (PRx) using non-invasive transcranial Doppler (TCD) derived indices.
- To evaluate the feasibility of using systolic flow index (Sx_a) and mean flow index (Mx_a) for PRx prediction.
- To develop and validate models for non-invasive PRx estimation.
Main Methods:
- Collected continuous middle cerebral artery cerebral blood flow velocity (CBFV) using robotic TCD alongside direct ICP.
- Derived PRx, Sx_a, and Mx_a from high-frequency signals.
- Employed autoregressive integrative moving average (ARIMA) and linear mixed effects (LME) models to predict PRx from TCD indices.
- Trained models on 80% of data and validated on the remaining 20% using correlation and Bland-Altman analysis.
Main Results:
- Optimal ARIMA structure for PRx was determined as (2,0,2).
- LME models PRx ∼ Sx_a and PRx ∼ Sx_a + Mx_a were identified as superior.
- Estimated and observed PRx showed strong correlation (r > 0.9) and acceptable agreement.
- Predicted PRx moderately correlated with observed PRx (r = 0.797 and r = 0.763).
Conclusions:
- It is possible to predict PRx using non-invasive TCD measures with ARIMA and LME modeling.
- This study presents preliminary findings on non-invasive PRx prediction.
- Further research is needed to refine and validate these non-invasive techniques.
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