Related Experiment Videos
Dynamic autoregulation testing in patients with middle cerebral artery stenosis
C Haubrich1, W Kruska, R R Diehl
1Department of Neurology, University Hospital Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany. Christina.Haubrich@t-online.de
Stroke
|July 5, 2003
Summary
Cross-spectral analysis (CSA) effectively assesses intracranial artery stenosis by analyzing cerebral blood flow velocity (CBFV) and blood pressure oscillations. This method reveals impaired arteriolar function with increasing stenosis severity.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Cardiovascular Physiology
Background:
- Dynamic autoregulation testing relies on cross-spectral analysis (CSA) of cerebral blood flow velocity (CBFV) and arterial blood pressure.
- The utility of CSA for assessing intracranial artery stenoses remained unclear.
Purpose of the Study:
- To investigate the application of CSA for evaluating stenoses in the middle cerebral artery (M1 segment).
- To determine if CSA can differentiate between varying degrees of M1 stenosis.
Main Methods:
- CSA was applied to 26 patients with low-, moderate-, and high-degree M1 stenoses and 14 controls.
- Spontaneous oscillations (M waves: 3-9 cpm; B waves: 0.5-3 cpm) in CBFV (transcranial Doppler) and beat-to-beat blood pressure were analyzed.
Main Results:
- Pulsatility indexes decreased with increasing stenosis severity, indicating hemodynamic relevance.
- M-wave phase shifts between CBFV and blood pressure reduced with higher stenosis degrees (controls: 44.6°, high-degree: 16.7°).
- B-wave phase relations shifted towards positive values with increasing stenosis (low-degree: -9.7°, high-degree: 50.9°).
Conclusions:
- Phase shifts in B and M waves indicate the degree of CBFV modulation autonomy.
- Increasing M1 stenosis impairs arteriolar function.
- CSA is a useful method for assessing intracranial artery stenosis.