Analysis of Energy Loss Mediated by an Alpha-1 Blocker in Patients with Benign Prostatic Hyperplasia Using a Virtual Urethra Processed from an Endoscopic Video Image

Sazuka, Tomokazu; Kambara, Yoichi; Ishii, Takuro; Nakamura, Kazuyoshi; Sakamoto, Shinichi; Naya, Yukio; Yamanishi, Tomonori; Ichikawa, Tomohiko; Igarashi, Tatsuo

doi:10.1089/end.2012.0078

Cited by 7 publications

(5 citation statements)

References 23 publications

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“…The presence of turbulent and vortex flow patterns visualized in this study aligns with previous expectations shown in previous studies using ultrasound decorrelation analyses, 28 color Doppler, 4 and CFD simulations 8 . CFD simulations have suggested that these flow patterns might result in increased hydraulic pressure loss in the urethra and could be associated with voiding symptoms, such as weak voiding 8,9,29 . In future studies, the hydrodynamic properties of urethral obstructions may be calculated using patient‐specific urinary flow vectors measured using a new ultrasound technique, such as CE‐UroVPI.…”

Section: Discussionsupporting

confidence: 88%

“…8 CFD simulations have suggested that these flow patterns might result in increased hydraulic pressure loss in the urethra and could be associated with voiding symptoms, such as weak voiding. 8,9,29 In future studies, the hydrodynamic properties of urethral obstructions may be calculated using patient-specific urinary flow vectors measured using a new ultrasound technique, such as CE-UroVPI. Furthermore, the high temporal resolvability of the CE-UroVPI framework can be used to observe various urinary tract deformations, including urethral wall shrinkage and external sphincter activity.…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, the flow direction in the urethra is non‐uniform because of the curved structure of the male urethra. Furthermore, especially for urethral obstruction, flow jet and vortex flow patterns have been expected in computational fluid dynamics studies 8,9 and experiments 10,11 . Therefore, quantitative flow measurement techniques should investigate the hydrodynamic interactions between the urinary tract and urinary flow.…”

Section: Introductionmentioning

confidence: 99%

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Transrectal ultrasound vector projectile imaging for time‐resolved visualization of flow dynamics in the male urethra: A clinical pilot study

Ishii,

Yamanishi,

Kamasako

et al. 2023

Medical Physics

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BackgroundQuantitative and comprehensive visualization of urinary flow dynamics in the urethra is crucial for investigating patient‐specific mechanisms of lower urinary tract symptoms (LUTS). Although some methods can evaluate the global properties of the urethra, it is critical to assess the local information, such as the location of the responsible lesion and its interactions with urinary flow in relation to LUTS. This approach is vital for enhancing personalized and focal treatments. However, there is a lack of such diagnostic tools that can directly observe how the urethral shape and motion impact urinary flow in the urethra.PurposeThis study aimed to develop a novel transrectal ultrasound imaging modality based on the contrast‐enhanced urodynamic vector projectile imaging (CE‐UroVPI) framework and validate its clinical applicability for visualizing time‐resolved flow dynamics in the urethra.MethodsA new CE‐UroVPI system was developed using a research‐purpose ultrasound platform and a custom transrectal linear probe, and an imaging protocol for acquiring urodynamic echo data in male patients was designed. Thirty‐four male patients with LUTS participated in this study. CE‐UroVPI was performed to acquire ultrasound echo signals from the participant's urethra and urinary flow at various voiding phases (initiation, maintenance, and terminal). The ultrasound datasets were processed with custom software to visualize urinary flow dynamics and urethra tissue deformation.ResultsThe transrectal CE‐UroVPI system successfully visualized the time‐resolved multidirectional urinary flow dynamics in the prostatic urethra during the initiation, maintenance, and terminal phases of voiding in 17 patients at a frame rate of 1250 fps. The maximum flow speed measured in this study was 2.5 m/s. In addition, when the urethra had an obstruction or an irregular partial deformation, the devised imaging modality visualized complex flow patterns, such as vortices and flow jets around the lesion.ConclusionsOur study findings demonstrate that the transrectal CE‐UroVPI system developed in this study can effectively image fluid‐structural interactions in the urethra. This new diagnostic technology has the potential to facilitate quantitative and precise assessments of urethral voiding functions and aid in the improvement of focal and effective treatments for patients with LUTS.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Transrectal ultrasound vector projectile imaging for time‐resolved visualization of flow dynamics in the male urethra: A clinical pilot study

Ishii,

Yamanishi,

Kamasako

et al. 2023

Medical Physics

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“…Sazuka et al reported that alpha-1 blocker therapy led to a decreased energy loss in the urine flow in the prostatic urethra in relation to the improvement of clinical symptoms. 21 Administration of an alpha-1 blocker enhances the dilation of the prostatic urethra under pressure of the urine stream. This dilation subsequently causes an improvement in the hydraulic energy loss during passage through the prostatic urethra.…”

Section: Discussionmentioning

confidence: 99%

Early effect of dutasteride added to alpha‐1 blocker therapy for patients with lower urinary tract symptoms associated with benign prostatic hyperplasia

et al. 2014

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Abbreviations & Acronyms 5ARI = 5-alpha-reductase inhibitors AUR = acute urinary retention BPE = benign prostatic enlargement BPH = benign prostatic hyperplasia CombAT = Combination of Avodart and Tamulosin DHT = dihydrotestosterone IPSS = International Prostate Symptom Score LUTS = lower urinary tract symptoms OAB = overactive bladder PRV = post-residual urine volume PSA = prostate-specific antigen PV = prostatic volume QOL = quality of life Objective: To investigate the hypothesis that 5-alpha-reductase inhibitors exert early ameliorative effects on voiding and storage symptoms in men with lower urinary tract symptomassociated benign prostatic hyperplasia. Methods: This was a prospective study involving the participation of eight outpatient clinics in Chiba Prefecture, Japan. The patients received dutasteride (0.5 mg) once daily orally for 24 weeks as an add-on to their ongoing therapy with an alpha-1 blocker. The study patients recorded their urinary symptoms every day for 14 days after starting dutasteride. The International Prostate Symptom Score, prostate volume, uroflowmetry results, and residual urine volume were checked at 3 and 6 months after starting dutasteride. Results: A total of eighty-eight patients participated in the present study; 74 were eligible for analysis of the early effects of dutasteride. The median age was 69.6 years (range 54-89), the median prostate volume was 50.3 mL (range 24.7-103.3) and the median International Prostate Symptom Score was 17.6 (range 8-35). The proportion of patients with International Prostate Symptom Score improvements (≥3 points, or ≥25%) or 3 points or more decreased International Prostate Symptom Score were defined effective, 37 (50.0%) and 47 (63.5%) experienced improvement at 1 month after administration, respectively. Conclusion: This is the first prospective clinical study to show the early beneficial effects of 5-alpha-reductase inhibitors for lower urinary tract symptom-associated benign prostatic hyperplasia. Patients with severe symptoms were found to be responsive to dutasteride. The influence of the placebo effect was not denied. Further study is necessary.

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“…7 In addition, we previously published video images of the prostatic urethra that had been recorded during cystourethroscopy at the time of the maximum desire to void. 11 Fluid dynamic analysis was carried out using the reproduced three-dimensional urethral images, and the hydraulic energy was calculated. Energy loss was related to the residual urine volume, but not to any other subjective or objective symptoms.…”

Section: Discussionmentioning

confidence: 99%

Impact of post‐void residual urine volume on intravesical recurrence after nephroureterectomy for upper urinary tract urothelial carcinoma

et al. 2019

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Abbreviations & Acronyms BPH = benign prostatic hyperplasia CI = confidence interval GC = gemcitabine, cisplatin HR = hazard ratio LUTS = lower urinary tract symptoms PSM = propensity scorematching RFS = recurrence-free survival TUR-P = transurethral resection of the prostate UC = urothelial carcinoma UUT-UC = upper urinary tract urothelial carcinoma Objective: To examine the impact of post-void residual urine volume on the risk of postoperative recurrence of intravesical carcinoma in patients with upper urinary tract urothelial carcinoma undergoing nephroureterectomy. Methods: We retrospectively reviewed the data of 81 patients who were admitted to Chiba University Graduate School of Medicine Hospital and underwent nephroureterectomy for upper urinary tract urothelial carcinoma without bladder carcinoma. We assessed the predictive factors for intravesical recurrence after nephroureterectomy in all patients. Next, we compared patients with and without a residual urine volume using propensity score-matching analysis. The presence of a residual urine volume was defined as ≥30 mL. Results: The median follow-up period among all patients was 48 months. The presence of pyuria and a residual urine volume were associated with bladder recurrence in the multivariate analysis. A total of 19 patients each were selected after matching, and we confirmed a significant difference between the presence and absence of a residual urine volume (P = 0.0291). The 2-year postoperative recurrence-free rate of patients with and without a residual urine volume was 32% and 82%, respectively. Conclusions: This is the first study to evaluate the post-void residual urine volume and intravesical recurrence rate after nephroureterectomy for upper urinary tract urothelial carcinoma. The presence of residual urine might be a risk factor for postoperative recurrence of intravesical carcinoma.

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Analysis of Energy Loss Mediated by an Alpha-1 Blocker in Patients with Benign Prostatic Hyperplasia Using a Virtual Urethra Processed from an Endoscopic Video Image

Abstract: Alpha-1 blocker therapy led to a decreased energy loss in the urine flow in the prostatic urethra in relation to the improvement of clinical symptoms. The cystourethroscopy could be a tool to assess the urethral resistance in patients with BPH using image processing methodology.

Cited by 7 publications

References 23 publications

Transrectal ultrasound vector projectile imaging for time‐resolved visualization of flow dynamics in the male urethra: A clinical pilot study

Transrectal ultrasound vector projectile imaging for time‐resolved visualization of flow dynamics in the male urethra: A clinical pilot study

Early effect of dutasteride added to alpha‐1 blocker therapy for patients with lower urinary tract symptoms associated with benign prostatic hyperplasia

Impact of post‐void residual urine volume on intravesical recurrence after nephroureterectomy for upper urinary tract urothelial carcinoma

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