title: Study of the effects of age and body mass index on the carotid wall vibration: extraction methodology and analysis.
abstract: This study aims to non-invasively extract the vibrations of the carotid wall and evaluate the changes in the carotid artery wall caused by age and obesity. Such evaluation can increase the possibility of detecting wall stiffness and atherosclerosis in its early stage. In this study, a novel method that uses a phase-tracking method based on the continuous wavelet transform calculates the carotid wall motion from the ultrasound radio frequency signals. To extract the high-frequency components of the wall motion, wall vibration, the empirical mode decomposition was then used. The posterior wall (intima-media) motion and vibration were extracted for 54 healthy volunteers (mean age: 33.87 ± 14.73 years), including 13 overweight subjects (body mass index > 25) and 14 female participants using their radio frequency signals. The results showed that the dominant frequency of the wall vibration correlates with age (r = -0.5887, p < 0.001) and body mass index (r = -0.4838, p < 0.001). The quantitative analysis further demonstrated that the dominant frequency of the vibration in the radial direction of the carotid wall decreases by age and is lower in overweight subjects. Besides, the peak-to-peak amplitude of the wall vibration showed significant correlations with age (r = -0.5456, p < 0.001) and body mass index (r = -0.5821, p < 0.001). The peak-to-peak amplitude also decreases by age and is lower in overweight subjects. However, there were no significant correlations between these features of the wall vibrations and systolic/diastolic blood pressure and sex. Our proposed measures were certified using the calculated arterial stiffness indices. The average power spectrum of the elderly subjects'wall motion in the frequency range of the wall vibration (>100 Hz) is decreased more in comparison with the young subjects. Our results revealed that the proposed method may be useful for detecting the stiffness and distortion in the carotid wall that occur prior to wall thickening caused by age as an early-stage atherosclerotic sign.
authors: Control and Intelligent Processing Center of Excellence, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran.
authors: Fereshteh
authors: F
authors: Yousefi Rizi
authors: Control and Intelligent Processing Center of Excellence, School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran ksetareh@ut.ac.ir.
authors: Seyed Kamaledin
authors: SK
authors: Setarehdan
authors: School of Electrical Engineering, Iran University of Science and Technology, Tehran, Iran.
authors: Hamid
authors: H
authors: Behnam
authors: Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Science, Tehran, Iran.
authors: Zahra
authors: Z
authors: Alizadeh Sani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000502:physiology*; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009991:Oscillometry / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012727:Sex Characteristics; D013314:Stress, Mechanical; D059289:Vascular Stiffness / Q000502:physiology*; D014732:Vibration; D055815:Young Adult
keywords: Carotid wall; age; body mass; empirical mode decomposition; phase tracking; wavelet transform