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Modification of low-frequency spontaneous oscillations in blood flow velocity in large- and small-artery disease
H Bäzner1, M Daffertshofer, M Konietzko
1Department of Neurology, University of Heidelberg, Klinikum Mannheim, Germany.
Insights
Patients with obstructive carotid disease show reduced low-frequency spontaneous oscillations (LFSOs) in middle cerebral arteries (MCAs), indicating altered cerebral blood flow dynamics. This desynchronization is more pronounced in large-artery disease compared to small-artery disease.
Area of Science:
- Neuroscience
- Cerebrovascular Physiology
- Medical Imaging
Background:
- Cerebral blood flow dynamics are crucial for brain health.
- Obstructive carotid disease and vascular encephalopathy can impair cerebral circulation.
- Low-frequency spontaneous oscillations (LFSOs) in middle cerebral arteries (MCAs) reflect cerebrovascular regulation.
Purpose of the Study:
- To investigate LFSOs in patients with obstructive carotid disease (large-artery disease) and subcortical vascular encephalopathy (small-artery disease).
- To compare LFSO characteristics between patient groups and healthy controls.
- To assess the impact of carotid disease on MCA blood flow velocity oscillations and synchronicity.
Main Methods:
- Bilateral MCA blood flow velocity was measured in 27 patients and 14 controls.
- Fourier transformation of MCA envelope curves identified LFSOs (0.01-0.50 Hz).
- Coefficient of variation (CoV) measured LFSO amplitude; coefficient of correlation (CoC) measured bilateral synchronicity.
Main Results:
- Control subjects exhibited normal CoV (5.38±1.82%) and CoC (0.91±0.06).
- Large-artery disease patients showed reduced ipsilateral CoV (3.91±1.10%) and impaired CoC (0.39±0.35), indicating desynchronization.
- Small-artery disease patients displayed bilateral CoV reduction (3.60±0.71%) and decreased CoC.
Conclusions:
- Obstructive carotid disease significantly alters MCA LFSO patterns, with reduced amplitude and desynchronization.
- Large-artery disease is associated with ipsilateral LFSO reduction and bilateral desynchronization.
- Small-artery disease demonstrates a more generalized reduction in LFSO activity and synchronicity.
Abstract:
During a 30-minute period, the blood flow velocity of both middle cerebral arteries (MCAs) was measured bilaterally in 27 patients with obstructive carotid disease (n = 18, large-artery disease) or subcortical vascular encephalopathy (n = 9, small-artery disease) and in control subjects of similar age and sex distribution (n = 14). To identify low-frequency spontaneous oscillations (LFSOs), MCA envelope curves were Fourier transformed with filter application to select low-frequency spectra (0.01-0.05, 0.05-0.15, 0.15-0.50 Hz). To measure the extent of LFSO amplitudes, a coefficient of variation (CoV) was calculated. In addition, a coefficient of correlation (CoC) was calculated to assess LFSO bilateral synchronicity. Normal ranges for CoV (mean = 5.38 +/- 1.82%) and CoC (mean = 0.91 +/- 0.06) were established in control subjects. In patients with large-artery disease, a significant CoV reduction was observed ipsilateral to the carotid lesion (CoV mean = 3.91 +/- 1.10%; p < 0.05, Wilcoxon's test) with a contralateral compensatory increase (CoV mean = 5.68 +/- 1.79%). In addition, a significant desynchronization of LFSOs was found in patients with large-artery disease (CoC = 0.39 +/- 0.35, p < 0.05). This was less obvious in patients with small-artery disease, who demonstrated a marked bilateral reduction of LFSO activity (CoV mean = 3.60 +/- 0.71%, p < 0.05) and CoC values.(ABSTRACT TRUNCATED AT 250 WORDS)