Is ultrasound estimation of bladder weight a useful tool in the assessment of patients with lower urinary tract symptoms?

An International Urogynecological Association (IUGA) / International Continence Society (ICS) joint report on the terminology for female pelvic organ prolapse (POP)

INTRODUCTION

The terminology for female pelvic floor prolapse (POP) should be defined and organized in a clinically-based consensus Report.

METHODS

This Report combines the input of members of two International Organizations, the International Urogynecological Association (IUGA) and the International Continence Society (ICS), assisted at intervals by external referees. Appropriate core clinical categories and a sub-classification were developed to give a coding to definitions. An extensive process of fourteen rounds of internal and external review was involved to exhaustively examine each definition, with decision-making by collective opinion (consensus).

RESULTS

A Terminology Report for female POP, encompassing over 230 separate definitions, has been developed. It is clinically-based with the most common diagnoses defined. Clarity and user-friendliness have been key aims to make it interpretable by practitioners and trainees in all the different specialty groups involved in female pelvic floor dysfunction and POP. Female-specific imaging (ultrasound, radiology and MRI) and conservative and surgical managements are major additions and appropriate figures have been included to supplement and clarify the text. Emerging concepts and measurements, in use in the literature and offering further research potential, but requiring further validation, have been included as an appendix. Interval (5-10 year) review is anticipated to keep the document updated and as widely acceptable as possible.

CONCLUSION

A consensus-based Terminology Report for female POP has been produced to aid clinical practice and research.

An International Urogynecological Association (IUGA) / International Continence Society (ICS) Joint Report on the Terminology for Female Pelvic Organ Prolapse (POP)

INTRODUCTION

The terminology for female pelvic floor prolapse (POP) should be defined and organized in a clinically-based consensus Report.

METHODS

This Report combines the input of members of two International Organizations, the International Urogynecological Association (IUGA) and the International Continence Society (ICS), assisted at intervals by external referees. Appropriate core clinical categories and a sub-classification were developed to give a coding to definitions. An extensive process of fourteen rounds of internal and external review was involved to exhaustively examine each definition, with decision-making by collective opinion (consensus).

RESULTS

A Terminology Report for female POP, encompassing over 230 separate definitions, has been developed. It is clinically-based with the most common diagnoses defined. Clarity and user-friendliness have been key aims to make it interpretable by practitioners and trainees in all the different specialty groups involved in female pelvic floor dysfunction and POP. Female-specific imaging (ultrasound, radiology and MRI) and conservative and surgical managements are major additions and appropriate figures have been included to supplement and clarify the text. Emerging concepts and measurements, in use in the literature and offering further research potential, but requiring further validation, have been included as an appendix. Interval (5-10 year) review is anticipated to keep the document updated and as widely acceptable as possible.

CONCLUSION

A consensus-based Terminology Report for female POP has been produced to aid clinical practice and research.

Imaging assessments of lower urinary tract dysfunctions: Future steps

Urodynamic tests are the standard diagnostic method for lower urinary tract dysfunctions (LUTD). However, these tests are invasive. The current review describes the noninvasive imaging techniques that have been used to monitor LUTD. The main imaging technologies that have been applied in diagnosing LUTD were 2D ultrasonography, Doppler ultrasonography, and near-infrared spectroscopy (NIRS). Ultrasonographic parameters, such as bladder wall thickness (BWT), detrusor wall thickness (DWT), and ultrasound-estimated bladder weight (UEBW), have been proposed as surrogates for bladder outlet obstruction (BOO) or detrusor overactivity (DO). Few studies have reported diagnostic cut-offs in diagnosing BOO or DO; thus, there is still a need to standardize the measurement method. NIRS can detect the hemodynamic changes related to DO and BOO in real-time, which could be advantageous in clinical practice, but the liability of NIRS to motion artefacts is a limitation. Bladder strain imaging in real-time using 2D ultrasound enables noninvasive estimation of the dynamic changes in the bladder wall during voiding. Many imaging techniques have been used to monitor the urinary bladder during the storage and voiding phases of the micturition cycle. These techniques were either static [i.e., measuring fixed parameters, such as BWT, DWT, UEBW, and intravesical prostatic protrusion (IVPP)] or dynamic (monitoring the structural and hemodynamic changes in the bladder wall in real-time). These techniques are currently being developed and standardized for potential use in diagnosing LUTD in clinical practice.

Correlation of ultrasound-estimated bladder weight to urodynamic diagnoses in women with lower urinary tract symptoms

OBJECTIVE

To test the hypothesis that the ultrasound-estimated bladder weight (UEBW) will correlate with the urodynamic diagnoses in women with lower urinary tract symptoms, in particular, detrusor underactivity and bladder outflow obstruction. Ultrasonography has been increasingly used in the assessment of lower urinary tract conditions.

METHODS

Adult women referred to the urodynamics suite for investigation of lower urinary tract symptoms were enrolled. After urodynamic evaluation, the portable BladderScan BVM 6500 device was used to calculate the bladder wall thickness and UEBW according to a standardized protocol. The patients were categorized according to the urodynamic findings. Women with normal findings, despite the symptoms for which they were referred, were used as the control group. The UEBW and bladder wall thickness measurements were compared between the groups and controls, using the Mann-Whitney and Kolmogorov-Smirnov tests. P <.05 was considered statistically significant.

RESULTS

A total of 187 women were enrolled. The UEBW was significantly lower in the patients with detrusor underactivity than in the controls (39.3 ± 3.0 g vs 45.7 ± 3.1 g, P <.001). Significant differences were also noted between the controls and patients with bladder outflow obstruction, with or without detrusor overactivity (45.7 ± 3.1 g vs 52.1 ± 3.9 g and 52.3 ± 6.2 g, respectively; P <.001 for both). The difference, in terms of the UEBW, between controls and patients with detrusor overactivity was not statistically significant (45.7 ± 3.1 g vs 45.3 ± 3.0, P > .05).

CONCLUSION

A significantly reduced UEBW in female patients with detrusor underactivity and a significantly increased UEBW in patients with bladder outflow obstruction were found. However, the finding of a significantly increased bladder weight in patients with detrusor overactivity was not confirmed in the present study.

Predictive value of resistive index, detrusor wall thickness and ultrasound estimated bladder weight regarding the outcome after transurethral prostatectomy for patients with lower urinary tract symptoms suggestive of benign prostatic obstruction

OBJECTIVES

To evaluate the value of three parameters from preoperative ultrasonography in predicting the outcome of transurethral prostatectomy in patients with lower urinary tract symptoms suggestive of benign prostatic obstruction.

METHODS

A total of 239 patients with lower urinary tract symptoms suggestive of benign prostatic obstruction entering our department for surgical therapy were prospectively recruited. All of them underwent both ultrasound and urodynamics before receiving standard transurethral prostatectomy by the same team of surgeons. For 202 patients, 6-month follow-up data were available after the surgery, including the International Prostate Symptom Score, the Quality of Life score and the maximum flow rate. Preoperative data stratified by different degree of recovery were compared and the influence of ultrasound parameters on the surgical outcome was analyzed by using logistic regression and receiver-operator characteristic curve analyses.

RESULTS

Baseline transitional zone index, intravesical prostatic protrusion, resistive index, detrusor wall thickness and ultrasonic estimation of bladder weight were significantly different between patients with an effective outcome and those with an ineffective outcome (P < 0.05). Resistive index, detrusor wall thickness and ultrasonic estimation of bladder weight were selected as independent factors correlated with the efficacy of transurethral prostatectomy by logistic regression (P < 0.05). All three factors had adequate area under receiver-operator characteristic curve with resistive index having the largest area (0.816, 95% CI 0.759-0.874). The combined positive predictive value in effective surgical outcome of resistive index, detrusor wall thickness and ultrasonic estimation was 96.3%.

CONCLUSIONS

Resistive index, detrusor wall thickness and ultrasonic estimation adequately predict the outcome of transurethral prostatectomy. Measuring these parameters by preoperative ultrasound might aid in determining the need for surgical intervention.

Non-invasive techniques in the diagnosis of bladder storage disorders

AIMS

To review clinical studies thus have been conducted to develop non-invasive diagnostic tools in the storage phase of the micturition cycle.

METHODS

Pub Med and Web of Science searches were carried out. The search covered the published data of non-invasive diagnostic techniques for detrusor overactivity (DO) and/or low compliance bladder in patients with urinary storage symptoms. The patho-physiological and clinical relevance of these methods were addressed. Diagnostic accuracy of these techniques was scrutinized.

RESULTS

Eighteen studies were included in the review. Ultrasonography and biomarkers were the most investigated techniques in the diagnosis of storage disorders. Assessment of diagnostic accuracy was possible in four studies. The heterogeneity in data reporting was too high to conduct a meta-analysis. Ultrasonographic parameters and cut-off values have been developed to define DO; such as bladder wall thickness (BWT), detrusor wall thickness and bladder weight. The likelihood ratio of vaginal ultrasonography in measurement of BWT was good. Guidelines are currently developing to standardize the methodologies applied in these techniques. Laboratory biomarkers of DO are gaining more attention recently, but their specificity for DO should be carefully defined. Near infrared spectroscopy (NIRS) is potential non-invasive diagnostic method that is able to detect the DO episodes in real time. However, a solution needs to be found for motion artifacts in this technique.

CONCLUSION

Non-invasive diagnostic techniques for storage disorders show limited progress with some limitations. Yet these techniques still cannot replace the standard filling cystometry in standard clinical practice.

Novel biomarkers for overactive bladder

Biomarkers constitute any objectively measurable indicator of a biological process. The classic biomarker used in the diagnosis of overactive bladder (OAB) has been detrusor overactivity, which is assessed urodynamically. In the search for a reliable, noninvasive alternative to urodynamics, interest has focused on genetic, imaging, and urinary factors. Along with other cytokines detectable in urine, prostaglandin E2 and nerve growth factor are indicators of low-grade inflammation. Although they correlate with OAB symptom severity, they have not been shown to have independent prognostic benefit. Imaging biomarkers have been investigated since the earliest days of video urodynamics. Despite extensive research on the ultrasonographic estimation of bladder wall thickness, further standardization of the technique is required before conclusions can be reached regarding diagnostic accuracy. Genetic factors contribute approximately half of the total risk for urgency incontinence. Functional polymorphisms of the cytochrome P450 IID6 gene significantly alter the metabolism of some commonly used anticholinergic drugs, but no genetic loci that influence risk of OAB have been definitively identified. The first genome-wide association studies for OAB are in progress, and should identify new susceptibility genes. Although current putative biomarkers correlate with OAB severity, much future work is required to assess their prognostic value, and establish their role in clinical practice.