| 1. |
- Ask, Per, et al.
(author)
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Bio-acoustic signals from stenotic tube flow : state of the art and perspectives for future methodological development.
- 1995
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In: Medical and Biological Engineering and Computing. - 0140-0118 .- 1741-0444. ; 33:5, s. 669-675
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Journal article (peer-reviewed)abstract
- To study the degree of stenosis from the acoustic signal generated by the turbulent flow in a stenotic vessel, so-called phonoangiography was first suggested over 20 years ago. A reason for the limited use of the technique today may be that, in the early work, the theory of how to relate the spectrum of the acoustic signal to the degree of the stenosis was not clear. However, during the last decade, the theoretical basis for this and other biological tube flow applications has been clarified. Now there is also easy access to computers for frequency analysis. A further explanation for the limited diagnostic use of bio-acoustic techniques for tube flow is the strong competition from ultrasound Doppler techniques. In the future, however, applications may be expected in biological tube flow where the non-invasive, simple and inexpensive bio-acoustic techniques will have a definite role as a diagnostic method.
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| 2. |
- Teriö, H, et al.
(author)
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Estimation of elastic properties in the urethral flow controlling zone by signal analysis of urodynamic pressure/flow data.
- 1989
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In: Medical and Biological Engineering and Computing. - 0140-0118 .- 1741-0444. ; 27:3, s. 314-321
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Journal article (peer-reviewed)abstract
- When urethral flow is treated as a lossless flow through an elastic tube, the relationship between the detrusor pressure and the urinary flow can be related to the elasticity of the flow-controlling zone of the urethra. A recent analytical method of describing urethral elasticity is implemented on a computer. The function p(Q) = pmo + LmQm is fitted to the recorded pressure/flow data. p(Q) is the detrusor pressure, Q the flow and pmo, m and Lm parameters. The elastic properties are then obtained as p(A) = pmo + KnAn, where p(A) is the static pressure, A the cross-sectional area of the flow-controlling zone and n and Kn calculated parameters. The urodynamic methods used and the computer implementation of the analytical method are described. In obstructed and unobstructed men without neurological symptoms, the elastic properties could be estimated in 94 per cent of the micturitions. The method makes it possible to describe urethral flow properties with Griffiths' model in a standardised way and compare results obtained by different investigators. It is recommended for quantification of urethral obstruction in research and for assessment of borderline cases of obstruction in clinical practice.
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