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Published on: September 19, 2018
A theory of aneurysm sounds
1Diagnostic Ultrasound Research Laboratory, University of Rochester Medical Center, NY 14642, USA.
Journal of Biomechanics
|September 1, 1995
Summary
This study proposes a nonlinear feedback model for intracranial aneurysm sounds, accurately predicting their narrow spectral widths. The theory explains observed frequencies and bandwidths, unlike linear resonance models.
Area of Science:
- Biomedical Engineering
- Acoustics
- Fluid Dynamics
Background:
- Narrow-band sounds are associated with intracranial aneurysms.
- Existing theories fail to explain the narrow spectral widths of these sounds.
Purpose of the Study:
- To propose a new theory for aneurysm sound generation.
- To explain the spectral characteristics of aneurysm sounds.
Main Methods:
- Modeling aneurysms using lumped mechanical elements.
- Analyzing aneurysm-blood flow interaction as a nonlinear feedback system.
- Applying describing function analysis from nonlinear control theory.
Main Results:
- The nonlinear model accurately predicts spectral widths and salient features of aneurysm sounds.
- Predicted center frequencies are around 400 Hz with quality factors of approximately 40.
- Linear resonance theories are insufficient to explain observed sound characteristics.
Conclusions:
- A nonlinear feedback mechanism is crucial for understanding aneurysm sounds.
- The proposed model provides a quantitatively accurate explanation for observed acoustic phenomena.
- This work challenges the adequacy of linear resonance theories in this context.
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