Clay modeling as a learning tool for medical trainees in urology: a narrative review and pilot study.

Background and Objective: Coronavirus disease 2019 (COVID-19) necessitated a transition to virtual education which limits hands-on opportunities and student engagement. To adapt, a pilot study investigating clay modeling as an alternative educational tool for medical students was incorporated in a virtual and in-person sub-internship for prospective urology applicants. We aim to review the literature supporting the use of clay modeling in medical education as well as describe our experience with the activity as a way to engage trainees and evaluate early surgical skills. Methods: The current literature on clay modeling in medical and early surgical education was reviewed using multiple search queries in PubMed. A total of thirteen publications were identified and analyzed, with zero articles specifically discussing urological anatomy or surgery. The pilot study was conducted through the traditional in-person sub-internship as well as through a novel virtual sub-internship at a single academic U.S. Urology residency program. Students were instructed to create a three-dimensional model of a genitourinary organ using modeling clay. Anonymized surveys were collected. Responses of virtual and in-person students were compared. Key Content and Findings: Clay modeling has been shown in the literature to be beneficial in medical and early surgical education through the use of active learning. Twenty-five total virtual (N=6) and in-person (N=19) students participated in the clay modeling activity. Survey ratings were mixed, with 100% positive responses amongst the virtual group in the areas of "relevance" and "creatively challenging" compared to the in-person cohort, 31.6% of whom responded positively to "relevance" and 47.4% for "creatively challenging" respectively. Overall, students responded positively for the exercise being "creatively challenging" (n=15, 60%) and "enjoyable" (n=16, 64%). Positive results echoed the student perspectives described in the current literature on clay modeling. Conclusions: Clay modeling has previously been used in the in-person classroom setting as a learning supplement or replacement for dissection classes but has not been previously described for use in the virtual learning environment or within the field of Urology. With ongoing need to develop novel teaching modalities, clay modeling may be a unique tool to enhance learning, and evaluate technical skill, and boost engagement for medical trainees.

Gender-based Disparity Exists in the Surgical Experience of Female and Male Urology Residents.

OBJECTIVE: To determine if a discrepancy exists in the number and type of cases logged between female and male urology residents. MATERIALS AND METHODS: ACGME case log data from 13 urology residency programs was collected from 2007 to 2020. The number and type of cases for each resident were recorded and correlated with resident gender and year of graduation. The median, 25th and 75th percentiles number of cases were calculated by gender, and then compared between female and male residents using Wilcoxon rank sum test. RESULTS: A total of 473 residents were included in the study, 100 (21%) were female. Female residents completed significantly fewer cases, 2174, compared to male residents, 2273 (P = .038). Analysis by case type revealed male residents completed significantly more general urology (526 vs 571, P = .011) and oncology cases (261 vs 280, P = .026). Additionally, female residents had a 1.3-fold increased odds of logging a case in the assistant role than male residents (95% confidence interval: 1.27-1.34, P < .001). CONCLUSION: Gender-based disparity exists within the urology training of female and male residents. Male residents logged nearly 100 more cases than female residents over 4years, with significant differences in certain case subtypes and resident roles. The ACGME works to provide an equal training environment for all residents. Addressing this finding within individual training programs is critical.

Practice Readiness? Trends in Chief Resident Year Training Experience Across 13 Residency Programs.

INTRODUCTION: Urology residency prepares trainees for independent practice. The optimal operative chief resident year experience to prepare for practice is undefined. We analyzed the temporal arc of cases residents complete during their residency compared to their chief year in a multi-institutional cohort. METHODS: Accreditation Council for Graduate Medical Education case logs of graduating residents from 2010 to 2022 from participating urology residency programs were aggregated. Resident data for 5 categorized index procedures were recorded: (1) general urology, (2) endourology, (3) reconstructive urology, (4) urologic oncology, and (5) pediatric urology. Interactions were tested between the trends for total case exposure in residency training relative to the chief resident year. RESULTS: From a sample of 479 resident graduates, a total of 1,287,433 total cases were logged, including 375,703 during the chief year (29%). Urologic oncology cases had the highest median percentage completed during chief year (56%) followed by reconstructive urology (27%), general urology (24%), endourology (17%), and pediatric urology (2%). Across the study period, all categories of cases had a downward trend in median percentage completed during chief year except for urologic oncology. However, only trends in general urology (slope of -0.68, P = .013) and endourology (slope of -1.71, P ≤ .001) were significant. CONCLUSIONS: Over 50% of cases completed by chief residents are urologic oncology procedures. Current declining trends indicate that residents are being exposed to proportionally fewer general urology and endourology cases during their chief year prior to entering independent practice.

A stepwise approach for functional near infrared spectroscopy measurement during natural bladder filling.

Background: Functional near infrared spectroscopy (fNIRS) is a versatile, noninvasive, and inexpensive tool that can be used to measure oxyhemoglobin (O2Hb) changes in the cortical brain caused by increasing bladder sensation during filling in upright posture. This study's purpose is to provide a rigorous methodologic template that can be implemented for comparative studies of fNIRS in the diagnosis and management of lower urinary tract symptoms including overactive bladder (OAB) and other forms of lower urinary tract dysfunction. Methods: Participants without any urologic conditions completed a validated oral hydration protocol facilitating and equilibrating natural bladder filling. First desire to void and real time bladder sensation (0-100%) were recorded using a Sensation Meter. A 24-channel fNIRS template simultaneously recorded prefrontal cortical O2Hb. Each channel was analyzed between "first desire" to void and 100% sensation, defined in this study as the period of "high sensation". Channels were sub-divided by cortical regions: right (nine channels), left (nine channels), middle (six channels). Results: A total of eight participants (male: n=4, female: n=4) were enrolled with mean age 39±19.9 years and body mass index (BMI) of 25±3.93 kg/m2. There were no differences in age, BMI, race, or OAB survey scores based on biological sex. Signal acquisition improved with power bank use, postural head support for motion reduction, and head cap optimization. Acceleration-based concurrent motion measurement was effectively utilized to remove motion artifacts. O2Hb concentration patterns appeared irregular during low sensation and increased during high sensation after first desire across the frontal cortex. Conclusions: Employing a stepwise approach, this study defined a methodological guide for improved prefrontal fNIRS signal acquisition and analysis during bladder filling. The technique demonstrated that prefrontal fNIRS cortical O2Hb increases with elevated bladder sensation in normal subjects and sets the stage for comparative studies in individuals with OAB and other forms of lower urinary tract dysfunction.

Race and Age-Related PSA Testing Disparities in Spinal Cord Injured Men: Analysis of National Veterans Health Administration Data.

Background: Prostate-specific antigen (PSA) testing remains controversial due to the debate about overdetection and overtreatment. Given the lack of published data regarding PSA testing rates in the population with spinal cord injury (SCI) within the US Department of Veterans Affairs (VA), there is concern for potential disparities and overtesting in this patient population. In this study, we sought to identify and evaluate national PSA testing rates in veterans with SCI. Methods: Using the VA Informatics and Computing Infrastructure Corporate Data Warehouse, we extracted PSA testing data for all individuals with a diagnosis of SCI. Testing rates were calculated, analyzed by race and age, and stratified according to published American Urological Association guideline groupings for PSA testing. Results: We identified 45,274 veterans at 129 VA medical centers with a diagnosis of SCI who had records of PSA testing in 2000 through 2017. Veterans who were only tested prior to SCI diagnosis were excluded. Final cohort data analysis included 37,243 veterans who cumulatively underwent 261,125 post-SCI PSA tests during the given time frame. Significant differences were found between African American veterans and other races veterans for all age groups (0.47 vs 0.46 tests per year, respectively, aged ≤ 39 years; 0.83 vs 0.77 tests per year, respectively, aged 40-54 years; 1.04 vs 1.00 tests per year, respectively, aged 55-69 years; and 1.08 vs 0.90 tests per year, respectively, aged ≥ 70 years; P < .001). Conclusions: Significant differences exist in rates of PSA testing in persons with SCI based on age and race. High rates of testing were found in all age groups, especially for African American veterans aged ≥ 70 years.

The Other Pandemic, Racism, in Urology.

Racism is deeply ingrained in our society with lasting effects within medicine. The COVID-19 pandemic further highlighted racial disparities in the medical field, including in the field of Urology. This has led to investigation regarding the effects of racism on education, patient care, and research within Urology. This article aims to review current literature on the "other pandemic," structural racism, within medicine and specifically urology and provide ways to combat its impact.

Longitudinal Changes in the Operative Experience for Junior Urology Residents.

OBJECTIVE: To evaluate longitudinal trends in surgical case volume among junior urology residents. There is growing perception that urology residents are not prepared for independent practice, which may be linked to decreased exposure to major cases early in residency. METHODS: Retrospective review of deidentified case logs from urology residency graduates from 12 academic medical centers in the United States from 2010 to 2017. The primary outcome was the change in major case volume for first-year urology (URO1) residents (after surgery internship), measured using negative binomial regression. RESULTS: A total of 391,399 total cases were logged by 244 residency graduates. Residents performed a median of 509 major cases, 487 minor cases, and 503 endoscopic cases. From 2010 to 2017, the median number of major cases performed by URO1 residents decreased from 64 to 49 (annual incidence rate ratio 0.90, P < .001). This trend was limited to oncology cases, with no change in reconstructive or pediatric cases. The number of major cases decreased more for URO1 residents than for residents at other levels (P-values for interaction <.05). The median number of endoscopic cases performed by URO1 residents increased from 85 to 194 (annual incidence rate ratio 1.09, P < .001), which was also disproportionate to other levels of residency (P-values for interaction <.05). CONCLUSION: There has been a shift in case distribution among URO1 residents, with progressively less exposure to major cases and an increased focus on endoscopic surgery. Further investigation is needed to determine if this trend has implications on the surgical proficiency of residency graduates.

A porcine bladder model of pre-clinical urodynamics demonstrates increased afferent nerve activity during filling.

INTRODUCTION AND OBJECTIVES: Urodynamics are the accepted gold standard for the evaluation of multiple forms of voiding dysfunction. However, the tests are expensive, invasive, poorly reproducible, and often prone to artifacts. Therefore, there is a pressing need to develop next-generation urodynamics. The purpose of this study was to develop a novel ex vivo porcine bladder urodynamics model with afferent pelvic nerve signaling that can be used as a preclinical surrogate for bladder sensation. METHODS: Porcine bladders including the ureters and vascular supply were harvested from local abattoirs using an established protocol in both male and female animals. Ex vivo bladder perfusion was performed using physiologic MOPS (3-(N-morpholino) propanesulfonic acid) buffer solution. The pelvic nerve adjacent to the bladder was grasped with micro-hook electrodes and electroneurogram (ENG) signals recorded at 20 kHz. Bladders were filled with saline at a nonphysiologic rate (100 mL/min) to a volume of 1 L using standard urodynamics equipment to simultaneously record intravesical pressure. ENG amplitude was calculated as the area under the curve for each minute, and ENG firing rate was calculated as number of spikes (above baseline threshold) per minute. At the conclusion of the experiment, representative nerve samples were removed and processed for nerve histology by a pathologist (hematoxylin and eosin and S100 stains). RESULTS: A total of 10 pig bladders were used, and nerve histology confirmed the presence of nerve in all adequately processed samples. Vesical pressure, ENG firing rate, and ENG amplitude all increased as a function of filling. During filling tertiles (low fill: min 1-3, med fill: min 4-6, and high fill: min 7-10), normalized pressures were 0.22 ± 0.04, 0.38 ± 0.05, and 0.72 ± 0.07 (cmH2O). Similarly, normalized ENG firing rates were 0.08 ± 0.03, 0.31 ± 0.06, and 0.43 ± 0.04 spikes/minute, respectively, and normalized nerve amplitudes were 0.11 ± 0.06, 0.39 ± 0.06, and 0.56 ± 0.14) µV, respectively. Strong relationships between average normalized pressure values and averaged normalized ENG firing rate (r2 = 0.66) and average normalized ENG amplitude (r2 = 0.8) were identified. CONCLUSIONS: The ex vivo perfused porcine bladder can be used as a preclinical model for the development of next-generation urodynamics technologies. Importantly, the model includes a reproducible method to measure afferent nerve activity that directly correlates with intravesical pressure during filling and could potentially be used as a surrogate measure of bladder sensation.

Corpus spongiosum flap: a unique technique in the management of urosymphyseal fistula.

Urosymphseal fistulas are a debilitating but treatable consequence of the combination of radiotherapy and endoscopic interventions in prostate cancer patients. Treatment includes fistula excision with a tissue flap to prevent communication of involved structures and provide structural and vascular support. We introduce a unique surgical approach of mobilizing and utilizing a corpus spongiosum flap in urosymphyseal fistula repair. A retrospective study identified two patients who underwent repair with a pedicled corpus spongiosum flap at our institution. The corpus spongiosum had adequate length and vascularization and limited the need for extra-pelvic muscle flaps, thus maintaining muscle integrity in the abdomen and thighs. Following extirpative surgery, both patients had durable fistula closure, decreased pelvic pain, and resolution of lower urinary tract symptoms and osteomyelitis. These cases highlight the potential of the corpus spongiosum to be a reasonable alternative interpositional flap in genitourinary reconstruction.

The Utility of Social Media on Urology Residency Doximity Rankings.

Background Social media has been more widely used by urology residency programs since the COVID-19 pandemic. There are no studies on the relationship between Doximity residency ranking and social media usage in urology. Objectives In this study, we aim to investigate the relationship between social media usage and the academic prestige of urology residency programs. Methods Residency reputation data was acquired from the Doximity Residency Navigator website. Twitter and Instagram activity in 2019 and 2021 was analyzed by collecting data on the total number of posts and followers. Data on residency virtual recruitment was obtained from Twitter and UroResidency website. Results By the end of 2021, 122/139 (87.8%) urology residency programs had a Twitter account and 61/139 (43.9%) had an Instagram account. A significant linear regression was found between Doximity ranking and the number of Twitter followers (p<0.001), Twitter posts (p=0.005), and Instagram followers (p=0.026). Virtual recruitment events were held by 107/139 (77%) programs in 2021. There was a significant linear regression between Doximity rankings and the number of virtual events (p<0.006). Conclusions Social media use by urology residency programs has increased since the COVID-19 pandemic. A program's higher Doximity ranking was correlated with the presence of Twitter and Instagram accounts as well as the number of Twitter followers, Twitter posts, and Instagram followers. There was a significant relationship between Doximity rankings and the number of hosted virtual events. Programs should consider increasing social media visibility to potentially improve their Doximity rankings.

Repeatability of Ultrasound-Defined Bladder Shape Metrics in Healthy Volunteers.

Purpose: Recent studies demonstrate the potential value of using non-invasive abdominal ultrasound to quantify bladder shape and its association with disorders of bladder filling and voiding. The aim of the present study was to assess the repeatability of ultrasound-defined bladder shape metrics within the same individual from multiple bladder fills and study visits. Patients and Methods: Healthy volunteers completed an oral hydration protocol with two weekly visits, each with two consecutive bladder fill-void cycles, providing four total fills per participant. Throughout filling, 3-dimensional (3-D) ultrasound images were recorded at 5-minute intervals. Perimeters were manually traced in six cross-sectional planes 30° apart using GE 4D-View software. Diameters, perimeters and cross-sectional areas for the transverse, sagittal and coronal planes were interpolated at three standard bladder volumes of 200, 300, and 400mL. To quantify repeatability, intraclass correlation coefficients (ICCs) and normalized mean absolute differences were calculated for each metric at each standard volume. Moderate and good repeatability were defined as ICC ≥0.5 and ICC ≥0.75, respectively. Results: Data from 16 healthy volunteers (9 females, 7 males) were analyzed. ICCs for the transverse vertical and horizontal diameters showed good repeatability, and five of nine perimeter ICCs showed moderate or good repeatability. The mean absolute difference/mean ratio was ≤4% for all perimeter measurements, indicating repeatability was consistent for multiple fills and visits. Conclusion: Initial evidence indicates that bladder shape metrics are relatively repeatable and therefore feasible to pursue as a non-invasive tool for potential evaluation of bladder function.

The impact the COVID-19 pandemic on urology literature: a bibliometric analysis.

Introduction: The COVID-19 pandemic has caused wide-reaching change to many aspects of life on a worldwide scale. The impact of these changes on peer-reviewed research journals, including those dedicated to urology, is still unknown. Material and methods: The Web of Science database was queried to retrieve all COVID-19 urological articles written in English language and published between January 1st, 2020 and December 10th, 2021. Only original and review articles were considered. A bibliometric analysis of the total number of papers, citations, institutions and publishing journals was performed. Non-COVID-19 publications were also retrieved to compare the duration of publication stages. Results: A total of 428 COVID-19 articles and 14,874 non-COVID-19 articles were collected. Significant differences in the duration of all the publication stages were found between COVID-19 and non-COVID-19 articles (all p <0.001). The most productive countries were the USA (100 articles), Italy (59 articles) and the United Kingdom (55 articles). The published literature has focused on four topics: COVID-19 genitourinary manifestations, management of urological diseases during the pandemic, repercussions on quality of life and impact on healthcare providers. Conclusions: A significant reduction in peer review time for COVID-19 articles might raise concerns regarding the quality of peer review itself. USA, Italy and UK published the highest number of COVID-19 related articles. Restrictive measures taken by governments to reduce the spread of infection had a strong impact on mental stress and anxiety of patients and healthcare professionals. A coerced deferral of diagnosis and treatment of emergencies and uro-oncological cases represented the most challenging task from a clinical standpoint.

Influence of visual and auditory cues about bladder volume on real-time filling sensation in healthy volunteers.

Auditory/visual (A/V) cues can trigger urgency in some individuals with overactive bladder (OAB), and patient-reported bladder sensation can be characterized during non-invasive oral hydration studies. The aim of this investigation was to test the hypothesis that A/V cues of bladder volume can alter patient-perceived bladder sensation during hydration studies. Healthy volunteers without urinary symptoms based on ICIq-OAB survey scores were recruited for an oral hydration study where they completed two fill/void cycles. The study was repeated twice, one week apart. Throughout bladder filling, participants reported real-time sensation (0-100%) using a Sensation Meter, and bladder volumes were measured at 5 min intervals with both 3D ultrasound and BladderScan®. Participants were divided into a Cues(+) group that was allowed to view their ultrasound images and hear volume measurements of the BladderScan® every 5 min and a Cues(-) group that was not exposed to these A/V cues. The A/V Cues(+) group had 10 participants (5 women and 5 men) and the Cues(-) group had 10 participants (7 women and 3 men). During the second visit, the Cues(+) group demonstrated decreased sensation compared to the Cues(-) group in the slower first fill, but not the faster second fill. The results of this study demonstrate that A/V cues about bladder volume can acutely alter sensation during hydration studies in healthy individuals with normal bladder function.

Management of Bladder Neck Contracture in the Age of Robotic Prostatectomy: An Evidence-based Guide.

The incidence of bladder neck contracture (BNC), or postprostatectomy vesicourethral anastomosis, has declined since the advent of robotic surgery. However, men with peripheral vascular comorbidities, among other factors, still have a high risk of developing this complication after any surgery that involves manipulation of the prostate. The best strategy for BNC management remains uncertain because of inconsistency in success for different approaches across studies. We reviewed the available evidence on BNC, including the results for endoscopic treatments, scar modulation therapies, and open and robotic bladder neck reconstruction. On the basis of these data, we propose a management flowchart. Patient baseline status and subjective goals and preferences remain crucial in management choices. PATIENT SUMMARY: Contracture of the bladder neck can occur as a complication after surgery to the prostate. We reviewed the evidence for various treatment approaches and propose a flowchart for management of this condition.

Irregular bladder shapes identified in women with overactive bladder: an ultrasound nomogram.

In this study, an ultrasound-based bladder shape nomogram was developed using data from women without overactive bladder (OAB) and tested in women with OAB to identify irregular bladder shapes. The goal was development of a nomogram that can ultimately be used for non-invasive identification of a bladder shape-associated OAB phenotype. Transabdominal 3-dimensional (3D) bladder ultrasound images were collected at 1-minute intervals during urodynamics studies and at 5-10-minute intervals during oral hydration studies. These prospective studies enrolled women with and without OAB based on International Consultation on Incontinence questionnaire on OAB (ICIq-OAB) question 5a (OAB 5a≥2, without OAB 5a<2). Bladder perimeters were manually traced and refined using GE 4D-View software. Nomograms for the transverse, sagittal and coronal perimeter-volume relationships were developed for women without OAB. A power model was used to approximate upper and lower nomogram bounds with 95% confidence intervals. Nomograms were tested using data from women with OAB, and each participant was classified as having an irregular bladder shape based on the number of perimeter values outside the nomogram bounds. Nomograms were developed using 533 images from 27 women without OAB (14 from urodynamics and 13 from hydration studies) and were tested using 264 images from 24 women with OAB (16 urodynamics and 8 hydration). The sagittal perimeter nomogram provided the best results, with irregular sagittal perimeters identified in 6/24 (25%) women with OAB and 0/27 (0%) without OAB. An irregular sagittal perimeter was significantly associated with OAB (P<0.05). Ultrasound-based nomograms may enable feasible, non-invasive identification of a subgroup of women with bladder shape-associated OAB.

Metastatic melanoma to the bladder presenting as autonomic dysreflexia in a patient with paraplegia.

We report a case of a 66-year-old male with T2 American Spinal Injury Association Impairment Scale (AIS) A paraplegia who presented to Urology with worsening autonomic dysreflexia. Work-up identified a bladder mass treated by transurethral resection and pathologically confirmed as melanoma. Additional work-up revealed metastatic melanoma to the back and brain. The patient completely recovered with no evidence of disease more than two years after completing therapy. In this report, we review the presentation of metastatic bladder melanoma presenting with autonomic dysreflexia, which has never been previously described, and discuss the prognosis of metastatic melanoma to the bladder.

Regulation of bladder dynamic elasticity: a novel method to increase bladder capacity and reduce pressure using pulsatile external compressive exercises in a porcine model.

PURPOSE: Dynamic elasticity is a biomechanical property of the bladder in which muscle compliance can be acutely adjusted through passive stretches and reversed with active contractions. The aim of this study was to determine if manipulating dynamic elasticity using external compression could be used as a novel method to acutely increase bladder capacity and reduce bladder pressure in a porcine model. METHODS: Ex vivo experiment: bladders underwent continuous or pulsatile compression after establishing a reference pressure at bladder capacity. Bladders were then filled back to the reference pressure to determine if capacity could be acutely increased. In-vivo experiments: bladders underwent five cycles of pulsatile external compression with ultrasound confirmation. Pre and post-compression pressures were measured, and pressure was measured again 10 min post-compression. RESULTS: Ex vivo experiment: pulsatile compression demonstrated increased bladder capacity by 16% (p = 0.01). Continuous compression demonstrated increased capacity by 9% (p < 0.03). Comparison of pulsatile to continuous compression showed that the pulsatile method was superior (p = 0.03). In-vivo experiments: pulsatile external compression reduced bladder pressure by 19% (p < 0.00001) with a return to baseline 10 min post-compression. CONCLUSIONS: These results suggest that regulation of bladder dynamic elasticity achieved with external compression can acutely decrease bladder pressure and increase bladder capacity. Pulsatile compression was found to be more effective as compared to continuous compression. These results highlight the clinical potential for use of non-invasive pulsatile compression as a therapeutic technique to increase bladder capacity, decrease bladder pressure, and reduce the symptoms of urinary urgency.

A preliminary study of bilateral color mapping of pig bladder vasculature demonstrates potential for acute hemi-ischemic events.

BACKGROUND: Chronic ischemia is a known risk factor for the development of lower urinary tract symptoms (LUTS) and bladder hypocontractility. Less is known, however, about the impact of acute ischemia. Classic teaching suggests that collateral circulation is robust in the bladder and, therefore, loss of a single source of blood flow should have no deleterious effect. This study aims to provide visual evidence that segmental vascular supply is critical for maintaining adequate perfusion to the bladder. METHODS: Ex vivo pig bladders were cannulated bilaterally in the superior vesical arteries and perfused using contrasting red and green dye. Images were collected at each step of the perfusion dyeing process and these images were analyzed using a custom program to calculate the average hue of each side. Statistical analysis was performed using Student's t-test. RESULTS: The two halves being perfused by separate arteries showed a statistically significant difference when compared (P<0.05) on both the outer wall (n=9) and in the mucosal layer (n=4). On the outside wall, the average normalized hue of the green halves was 27.5°±14.3°, while the average normalized hue of the red halves was -58.7°±3.1°. In the mucosa, the average normalized hue of the green halves was 34.5°±17.4°, while the average normalized hue of the red halves was -51.5°±3.5°. CONCLUSIONS: This study identified a novel color mapping method to study pig bladder vascular supply. The results demonstrated a lack of collateral blood flow, highlighting the possibly of acute hemi-ischemic event. However, further research in the effect of acute ischemia on bladder function is necessary.

Bladder wall micromotion measured by non-invasive ultrasound: initial results in women with and without overactive bladder.

OBJECTIVE: Rhythmic contractions of the bladder wall during filling result from the synchronization of bladder wall micromotion and are often observed in the urodynamic tracings of individuals with urinary overactive bladder (OAB). This study's objective was to develop a novel, non-invasive method to measure bladder wall micromotion and to conduct an initial study to test the hypothesis that elevated micromotion is associated with OAB. METHODS: This prospective study enrolled women with OAB and asymptomatic volunteers as measured by the ICIQ-OAB survey. After filling the bladder to 40% cystometric capacity, 85 second cine-loops were obtained using a GE Voluson E8 ultrasound system with an 8 MHz curved, abdominal probe. A custom correlation-based texture tracking MATLAB algorithm was used to measure changes in the bladder wall thickness over time and correlate with changes in vesical pressure. Significant bladder wall micromotion was defined as changes in wall thickness with amplitudes higher than 0.1 mm in the frequency range of 1.75-6 cycles/minute as calculated from Fast Fourier Transform (FFT) analysis. The micromotion algorithm was tested on 30 women including 17 with OAB and 13 asymptomatic volunteers. RESULTS: Micromotion was identified in 41% of subjects with OAB and 0% of asymptomatic volunteers, indicating a significant association of micromotion with OAB (Fisher's exact test, P=0.010). Micromotion was also found to have a significant association with a clinical diagnosis of detrusor overactivity (Fisher's exact test, P=0.031). Frequencies with elevated micromotion correlated with frequencies of vesical pressure fluctuations. CONCLUSIONS: The feasibility of a non-invasive method to measure bladder wall micromotion was demonstrated using transabdominal anatomical motion mode (M-mode) ultrasound. Presence of micromotion was significantly associated with OAB and with urodynamic-identified rhythm.