The Location and Distribution of Transurethral Bulking Agent: 3-Dimensional Ultrasound Study

Imaging the Female Urethra: US and MRI in Cystic and Solid Pathologic Conditions

The female urethra can be affected by numerous pathologic conditions, many of which are infrequent and often underdiagnosed, particularly before the introduction of MRI. Diagnosing urethral pathologic conditions is challenging due to ambiguous signs and symptoms, nonspecific physical examinations, atypical presentations (such as benign conditions mimicking malignant disorders), and large lesions. Various imaging techniques, including transperineal or transvaginal US and MRI, are essential for accurate anatomic and tissue characterization. Female urethral pathologic conditions can be categorized into cystic lesions (with urethral diverticulum as the most common), benign and malignant solid urethral lesions, and iatrogenic lesions. Defining the location of the pathologic finding is the first step in radiologic diagnosis. By analyzing tissue characteristics (cystic versus noncystic), shape, morphology, and location (including urethral dependence and relationship to the pubic symphysis), an accurate diagnosis can often be achieved. Identifying whether a lesion is urethral-dependent helps distinguish between urethral and other conditions, such as Bartholin gland and Gartner duct cysts. Radiologists must recognize these features to determine the most appropriate diagnostic and therapeutic strategies. ©RSNA, 2025 Supplemental material is available for this article.

Role of 3D ultrasound in the treatment of stress urinary incontinence with polyacrylamide hydrogel (Bulkamid®) - A pilot study

INTRODUCTION AND HYPOTHESIS

Polyacrylamide hydrogel (PAHG) is a bulking agent used in treatment of stress urinary incontinence (SUI) in women. Some women experience an improvement or cure in stress urinary incontinence (SUI) symptoms lasting only a few weeks after the injection of the bulking agent. The aim of this study was to use three-dimensional ultrasound (3DUS) to describe the changes in volume, number of deposits and echogenicity of the bulking agent 3 months after PAHG injection.

METHODS

Prospective cohort study of fourteen women with SUI or mixed primarily SUI, who underwent an injection of PAHG. The subjective outcome was evaluated with Patient Global Impression of Improvement questionnaire. 3DUS was performed in all patients immediately after injection of PAHG and again at 3 months follow-up.

RESULTS

The study found a mean 36.5 % loss in bulking agent volume during the study period. A total of 53 PAHG deposits were found by ultrasound immediately after injection. At 3 months follow-up 41 PAHG deposits were left. All deposits were hypoechogenic immediately after injection and only 24 % of demonstrated PAHG collections had a hypoechoic echogenicity at 3 months follow-up.

CONCLUSIONS

More than 1/3 of volume of injected PAHG and 23 % of deposits could not be found by 3DUS at 3 months follow-up. Only 24 % of PAHG injections in our patients had hypo-echoic echogenicity at 3 months follow-up. Larger 3DUS studies with longer follow-up and focus on exact location of the PAHG injections are important future studies.

Does aging affect the elastic properties of the bladder and the urethra in nulliparous women: An ultrasound shear-wave elastography study

OBJECTIVE

To investigate how aging and menopausal status in absence of pregnancy and childbirth affect the elasticity of the bladder and urethra.

STUDY DESIGN

A single-center prospective observational study including nulliparous 10 pre- and 12 postmenopausal women. Data collection included baseline characteristics, physical examination data, questionnaire scores, PDFI and the Pelvic Floor Impact Questionnaire, and pelvic floor sonographic measurements as well as elastography measurements. The shear wave elastography (SWE) of tissue was measured using Kilopascal (kPa). The elastography measurements were taken over the rhabdosphincter, the suburethra smooth muscle, and the trigonal areas.

RESULTS

A total of 22 nulliparous subjects were enrolled in the study. The cohort's mean age was 43.5 years, the mean body mass index (BMI) was 26.8, and 86% were of Caucasian ethnicity. The postmenopausal group was older and with higher BMI (p < 0.001 and p = 0.05). They also had higher scores in all the questionnaires (p < 0.05 for all) and did not demonstrate prolapse in any compartments. The SWE results for the whole group were 35.2 kPa in the rhabdosphincter measuring point, 40.2 kPa in the sub-urethra point, and 20.6 kPa in the trigone point. Comparing the premenopause and postmenopause groups, we found lower measurements in the rhabdosphincter area and equivocal measurements for the suburethral zone. No statistically significant differences were found between the groups CONCLUSIONS: The elastic properties of the different bladder components and the urethra change with age and menopause. Using elastic properties of the tissues, we can further explore both stress urinary incontinence and overactive bladder.

Ultrasonographic Imaging of the Pelvic Floor

This article discusses various pelvic floor ultrasonographic modalities and the clinical applications of ultrasonography of the pelvic floor. Ultrasonography provides a detailed anatomic assessment of the muscles and surrounding organs of the pelvic floor. Different anatomic variabilities and pathologic conditions, such as prolapse, fecal incontinence, urinary symptoms, vaginal wall cysts, synthetic implanted material, and pelvic pain, are assessed with pelvic floor ultrasonography. This imaging modality is an important adjunct to the evaluation and diagnosis of pelvic floor disorders.

Association between 3D endovaginal and 2D perineal pelvic floor ultrasound findings and symptoms in women presenting with mid-urethral sling complications

OBJECTIVES

To present the characteristics of women attending a tertiary urogynecology pelvic floor scan clinic with mid-urethral sling (MUS) complications and examine the association between patient symptoms and findings on two-dimensional (2D) perineal and three-dimensional (3D) endovaginal ultrasound.

METHODS

This was a cross-sectional study of all women with MUS complications referred to a specialist pelvic floor ultrasound clinic between October 2016 and October 2018. Detailed history was obtained regarding their symptoms and time of onset. All patients underwent 2D perineal and 3D endovaginal ultrasound assessment. The association between patient symptoms and ultrasound findings was evaluated using logistic regression analysis. Only symptomatic women with a single MUS, without other pelvic floor mesh, prior mesh excision or bulking agents, were included in the regression analysis.

RESULTS

A total of 311 women with a history of MUS surgery were seen during the study period. Vaginal and/or non-vaginal pain was reported by 80% of patients and this was the primary presenting complaint in 59% of the patients. One-third of the patients reported symptoms starting within 4 weeks after surgery. The data of 172 patients were included in the regression analysis. MUS position within the rhabdosphincter was significantly associated with voiding dysfunction (odds ratio (OR), 10.6 (95% CI, 2.2-50.9); P = 0.003). Voiding dysfunction was highest in those with C-shaped MUS both at rest and on Valsalva maneuver (OR, 3.2 (95% CI, 1.3-7.6); P < 0.001). MUS position in the distal third of the urethra was significantly associated with a higher rate of recurrent urinary tract infection (OR, 2.9 (95% CI, 1.3-6.3); P = 0.01).

CONCLUSIONS

Pelvic floor ultrasound can provide insight into the position and shape of the MUS, which could explain some patient symptoms and guide management or surgical planning. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Feasibility, technique and accuracy of ultrasound-guided transurethral injections into the urinary sphincter of female cadavers: proof of concept

BACKGROUND

The injection of muscle precursor cells (MPC) into the external urinary sphincter muscle (EUS) is a promising therapeutic option for regenerative treatment of stress urinary incontinence (SUI). The objective of the present project was to conduct a pre-clinical trial to investigate the feasibility and accuracy of ultrasound (US) guided, transurethral injections into the EUS of female cadavers.

METHODS

This is a prospective, anatomical, interventional and radiological cadaveric laboratory investigation. Two urologists performed transurethral US-guided injections to deliver nano-iron particles into the EUS. The intervention was performed in three unfixed, fresh female cadavers. Each cadaver received MRI before and CT as well as MRI of the pelvis after the injections.

RESULTS

The precision and accumulation of nano-iron particles in the EUS was compared using a rating scale to evaluate left versus right and anterior versus posterior distribution in axial and sagittal orientation with US, MRI and CT. The accuracy of our US-guided injections into the anterior target region yielded 4 points on the rating scale. Adequate precision and accumulation of particles in the left versus right EUS were also demonstrated (3 vs. 3.33 points, respectively). Signal intensity in MRI revealed a mean ratio of 0.33 before and after injection. CT scans showed no relevant artefacts impairing the assessment.

CONCLUSION

US-guided, transurethral injection into the EUS is feasible and imaging reveals a precise accumulation in the target region. Our method provides an appropriate approach to deliver MPC in the EUS muscle for a regenerative treatment of SUI in the near future.

Injection of Urethral Bulking Agents

Urethral injection is a safe and minimally invasive method of treating female stress urinary incontinence with multiple bulking agents currently commercially available. Although there are numerous studies that demonstrate efficacy, long-term success is not yet proven. This article aims to describe the mechanism of action and properties of various agents, patient selection factors, available techniques for injection, outcomes of urethral injections, and complications associated with the procedure.

Agreement between simple catheter method and 3D transperineal ultrasound for assessing urethral length measurement before stress urinary incontinence treatment

AIMS

Optimal placement of periurethral material has an important role in treatment efficacy with stress urinary incontinence (SUI). The validity of methods for determining urethral length and the precise location of the mid-urethral complex for SUI treatment have been sparsely studied. The aim of this study was to investigate the agreement between urethral lengths measured with a catheter and by transperineal ultrasound.

METHODS

Fifty-seven women with SUI or mixed urinary incontinence (MUI) with predominant stress symptoms were recruited. The urethral length was assessed with 3D transperineal ultrasound and measurements were taken offline from the postero-inferior margin of the pubic symphysis to the bladder neck. Then, it was measured with a foley catheter by another evaluator, blinded to the ultrasound data. The distance between the inflated balloon and the urethral meatus was considered.

RESULTS

Thirty-three women (58%) had SUI and 24 (42%) had MUI. The mean urethral length evaluated with ultrasound and the catheter were 3.03 ± 0.34 cm and 3.02 ± 0.41 cm (P = 0.857), respectively. Agreement between the two methods as assessed by the intra-class correlation coefficient was 0.90 (CI0.82-0.94, P ≤ 0.001). Limits of agreement (Bland-Altman) were +0.46 to -0.45 cm, with a mean difference of -0.01 ± 0.23 cm.

CONCLUSIONS

Findings of this study, reveal an excellent agreement between a simple catheter technique and ultrasound assessment for measuring urethral length, with a small mean bias and clinically acceptable limits of agreement. This provides relevant information in clinical practice for determining optimal placement of periurethral material or mid-urethral tape for SUI treatment.