Development of Noninvasive Velocity Flow Video Urodynamics Using Doppler Sonography. Part Ii

Ozawa, Hideo; Kumon, Hiromi; Yokoyama, Teruhiko; Watanabe, Toyohiko; Chancellor, Michael B.

doi:10.1097/00005392-199811000-00052

The Journal of Urology

1998

DOI: 10.1097/00005392-199811000-00052

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Development of Noninvasive Velocity Flow Video Urodynamics Using Doppler Sonography. Part Ii

Hideo Ozawa¹,

Hiromi Kumon²,

Teruhiko Yokoyama³

et al.

Abstract: The concept of noninvasive pressure flow-like urodynamic evaluation based on Doppler ultrasound is feasible. Parameters of flow velocity as well as functional cross-sectional area can be used in the diagnosis of bladder outlet obstruction and to localize the site of obstruction.

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Cited by 3 publications

References 12 publications

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Experimental and clinical trial of measuring urinary velocity with the pitot tube and a transrectal ultrasound guided video urodynamic system

Tsujimoto¹,

Nose²,

Ohba³

2003

Int J of Urology

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Background : The pitot tube is a common device to measure flow velocity. If the pitot tube is used as an urodynamic catheter, urinary velocity and urethral pressure may be measured simultaneously. However, to our knowledge, urodynamic studies with the pitot tube have not been reported. We experimentally and clinically evaluated the feasibility of the pitot tube to measure urinary velocity with a transrectal ultrasound guided video urodynamic system. Methods : We carried out a basal experiment measuring flow velocity in model urethras of 4.5-8.0 mm in inner diameter with a 12-Fr pitot tube. In a clinical trial, 79 patients underwent transrectal ultrasound guided video urodynamic studies with the 12-Fr pitot tube. Urinary velocity was calculated from dynamic pressure (P d ) with the pitot tube formula and the correcting equation according to the results of the basal experiment. Results : Velocity measured by the pitot tube was proportional to the average velocity in model urethras and the coefficients were determined by diameters of model urethras. We obtained a formula to calculate urinary velocity from the basal experiment. The urinary velocity could be obtained in 32 of 79 patients. Q max was 8.1 ± 4.3 mL/s (mean ± SD; range, 18.4-1.3 mL/s), urethral diameter was 7.3 ± 3.0 mm (mean ± SD; range, 18.7-4.3 mm) and urinary velocity was 69.4 ± 43.6 (mean ± SD; range, 181.3-0 cm/s) at maximum flow rate. The correlation coefficient of Q max measured by a flowmeter versus Q dv flow rate calculated with urethral diameter and velocity was 0.41 without significant difference. Conclusion : The use of the pitot tube as an urodynamic catheter to a transrectal ultrasound-guided video urodynamic system can measure urethral pressure, diameter and urinary velocity simultaneously. However, a thinner pitot tube and further clinical trials are needed to obtain more accurate results.

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Experimental and clinical trial of measuring urinary velocity with the pitot tube and a transrectal ultrasound guided video urodynamic system

Tsujimoto¹,

Nose²,

Ohba³

2003

Int J of Urology

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Basic study on velocity‐flow urodynamics using Doppler sonography: Simultaneous detection of cavitation and Doppler signals in an artificial urethral model

et al. 2004

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Background: We have developed velocity-flow urodynamics using Doppler sonography based on the hypothesis that microbubbles formed in the urethra are responsible for Doppler signals. In order to confirm this hypothesis derived from Bernoulli's principle, we investigated the simultaneous detection of cavitation noise and Doppler signals in an experimental system. Methods: An experimental circuit was built in which a stenosis was created using a glass or silicon tube with tap water used as the sample fluid. Doppler signals, pressure before and after the stenosis, flow rate, flow velocity and cavitation noise were measured. Direct detection of cavitation with a high-speed charged-coupled device (CCD) camera was conducted in the glass tube. The relationship between cross-sectional area and flow velocity in terms of the detection of Doppler signals was analyzed in the silicon tube study. Results:In the glass tube study, a high-speed CCD camera clearly detected masses of microbubbles associated with cavitation. The range of flow rates creating cavitation completely corresponded with those producing Doppler signals detected by ultrasonography. A similar correlation was observed in the silicon tube study, which showed that a low flow velocity of 41.5 cm/sec through a stenosis with a cross-sectional area of 20 mm 2 created Doppler signals at a flow rate of 8.3 mL/sec. Conclusion:The results of the present study confirmed that microbubbles created in flowing urine are responsible for Doppler signals. Measurement of velocity-flow urodynamics has great potential to become a non-invasive and reliable alternative to conventional pressure-flow urodynamic studies.

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Change in Parameters before and after Alpha-1-Blocker Therapy for Men with Lower Urinary Tract Symptoms Using Color Doppler Ultrasound Urodynamics: Possible Application for Prediction of Clinical Outcome

Watanabe¹,

Yokoyama²,

Ozawa³

et al. 2004

Urol Int

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Introduction: We previously developed a noninvasive video urodynamic study using color Doppler ultrasonography. We sought the best flow velocity-related parameter which would allow prediction of an improvement in lower urinary tract symptoms (LUTS) after α₁-blocker treatment. Methods: Twenty-two men with benign prostatic hyperplasia who were treated with a nonselective α₁-blocker (urapidil) were included. Subjective symptoms were evaluated using the International Prostate Symptom Score (IPSS) before and after α₁-blocker treatment. We measured the flow velocities using a transperineal ultrasound technique in the distal prostatic urethra just proximal to the external urethral sphincter (V₁) and in the sphincteric urethra (V₂), and used them to obtain the velocity ratio (VR = V₁/V₂). The corresponding functional cross-sectional areas of the urethra at these two sites (A₁ and A₂) were calculated as Q_max/V. All these parameters obtained by the velocity-flow urodynamics were compared before treatment and after 4 weeks. Results: After treatment, V₁ and VR were decreased, and A₁ was increased. V₂ correlated best with the change in IPSS before and after α₁-blocker therapy, with Spearman’s rho of 0.584. All men with V₂ exceeding 50 cm/s did not show an improvement in the LUTS. Conclusions: The maximum flow velocity at the sphincteric urethra (V₂) can predict the subjective outcome of α₁-blocker treatment. The velocity-flow parameters changed after α₁-blocker treatment. We confirmed that the transperineal ultrasound urodynamic study is not only noninvasive but also informative.

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Development of Noninvasive Velocity Flow Video Urodynamics Using Doppler Sonography. Part Ii

Abstract: The concept of noninvasive pressure flow-like urodynamic evaluation based on Doppler ultrasound is feasible. Parameters of flow velocity as well as functional cross-sectional area can be used in the diagnosis of bladder outlet obstruction and to localize the site of obstruction.

Cited by 3 publications

References 12 publications

Experimental and clinical trial of measuring urinary velocity with the pitot tube and a transrectal ultrasound guided video urodynamic system

Experimental and clinical trial of measuring urinary velocity with the pitot tube and a transrectal ultrasound guided video urodynamic system

Basic study on velocity‐flow urodynamics using Doppler sonography: Simultaneous detection of cavitation and Doppler signals in an artificial urethral model

Change in Parameters before and after Alpha-1-Blocker Therapy for Men with Lower Urinary Tract Symptoms Using Color Doppler Ultrasound Urodynamics: Possible Application for Prediction of Clinical Outcome

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