title: Wavelet transform analysis to assess oscillations in pial artery pulsation at the human cardiac frequency.
abstract: Pial artery adjustments to changes in blood pressure (BP) may last only seconds in humans. Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) in humans, we aimed to assess the relationship between spontaneous oscillations in BP and cc-TQ at frequencies between 0.5 Hz and 5 Hz. We hypothesized that analysis of very short data segments would enable the estimation of changes in the cardiac contribution to the BP vs. cc-TQ relationship during very rapid pial artery adjustments to external stimuli. BP and pial artery oscillations during baseline (70s and 10s signals) and the response to maximal breath-hold apnea were studied in eighteen healthy subjects. The cc-TQ was measured using NIR-T/BSS; cerebral blood flow velocity, the pulsatility index and the resistive index were measured using Doppler ultrasound of the left internal carotid artery; heart rate and beat-to-beat systolic and diastolic blood pressure were recorded using a Finometer; end-tidal CO2 was measured using a medical gas analyzer. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations. The recordings lasting 10s and representing 10 cycles with a frequency of ~1 Hz provided sufficient accuracy with respect to wavelet coherence and wavelet phase coherence values and yielded similar results to those obtained from approximately 70cycles (70s). A slight but significant decrease in wavelet coherence between augmented BP and cc-TQ oscillations was observed by the end of apnea. Wavelet transform analysis can be used to assess the relationship between BP and cc-TQ oscillations at cardiac frequency using signals intervals as short as 10s. Apnea slightly decreases the contribution of cardiac activity to BP and cc-TQ oscillations.
authors: Institute of Human Physiology, Medical University of Gdansk, Gdansk, Poland. Electronic address: pawelwinklewski@wp.pl.
authors: P J
authors: PJ
authors: Winklewski
authors: Department of Radiology Informatics and Statistics, Medical University of Gdansk, Gdansk, Poland.
authors: M
authors: M
authors: Gruszecki
authors: Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland; International Clinical Research Center, St. Anne's University Hospital in Brno (FNUSA), Brno, Czech Republic.
authors: J
authors: J
authors: Wolf
authors: Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland.
authors: E
authors: E
authors: Swierblewska
authors: Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland.
authors: K
authors: K
authors: Kunicka
authors: Institute of Human Physiology, Medical University of Gdansk, Gdansk, Poland.
authors: M
authors: M
authors: Wszedybyl-Winklewska
authors: Department of Computer Communications, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland.
authors: W
authors: W
authors: Guminski
authors: Institute of Human Physiology, Medical University of Gdansk, Gdansk, Poland.
authors: J
authors: J
authors: Zabulewicz
authors: Institute of Human Physiology, Medical University of Gdansk, Gdansk, Poland.
authors: A F
authors: AF
authors: Frydrychowski
authors: Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland.
authors: L
authors: L
authors: Bieniaszewski
authors: Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland; International Clinical Research Center, St. Anne's University Hospital in Brno (FNUSA), Brno, Czech Republic.
authors: K
authors: K
authors: Narkiewicz
mesh_terms: D000328:Adult; D001049:Apnea / Q000473:pathology; D001158:Arteries / Q000473:pathology*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure; D062485:Breath Holding; D002343:Carotid Artery, Internal / Q000473:pathology; D002560:Cerebrovascular Circulation; D004562:Electrocardiography; D005260:Female; D064368:Healthy Volunteers; D006339:Heart Rate; D006801:Humans; D008297:Male; D009991:Oscillometry / Q000379:methods*; D010841:Pia Mater / Q000098:blood supply*; D014172:Transillumination / Q000379:methods; D017585:Ultrasonography, Doppler, Transcranial; D058067:Wavelet Analysis; D055815:Young Adult
keywords: Cardiac frequency; Cerebral blood flow; NIR-T/BSS; Pial artery; Wavelet transform analysis